heat in' history
Artwork-A Review ofResearch Work Done byProfessor Arthur (Art) E. Bergles

Professor Arthur E Bergles has made major contributions in a number ofareas in heat transfer.
This article presents a review of300 papers published by him, and with his students and co-workers.
through December 1996. Professor Bergles' research work can be broadlv categorized into sevenareas: (I) enhanced heat transfer. (2) two-phase flow and heat transfer. (3) heat transfer 10
refrigerants (boiling and condensation). (4) cooling of electronic components, (5) laminar internal
flow, (6) review and general articles, and (7) history of heat transfer. This research. conducted overmore than 30 years, has produced a wealth of high-quality experimental data, theoretical models,and practical applications. One of the major objectives of this article is 10 highlight thesecontributions and identify their sources, to facilitate future researchers and designers in developing
new theoretical models and in designing industrial equipment. The present article presents acomprehensive survey of his research work.

The research work of Professor Bergles has been
conducted during a span of over 30 years. Professor
Bergles, through his extensive reports and publications,has played a major role in heat transfer research over
several decades. He defined research needs through visionary review papers. Further, he identified the potential benefits of conducting fundamental and appliedresearch work for industrial applications, especially inenhanced heat transfer. And finally, as a true researcher
in his soul, he set out to obtain invaluable experimental
data as well as insight into the underlying mechanisms
governing related phenomena in numerous fundamental
heat transfer problems.
The experiments conducted by Professor Bergles
not only provide valuable data, they also bring out theI am deeply indebted to Professor Bergles. who extended untiring supportin preparing this article. He made his research articles available to me inwell-organized form and helped me through his illuminating discussions
and prompt responses. I would like to extend special thanks to Professor
Bora B. Mikic at the Massachusetts Institute of Technology for his constantencouragement and many constructive comments. I sincerely appreciate his
generous help.
This article is essentially similar to one published under the same title
in Proces s, Enhanced. and Muuiphase Heat Transjer, A Festschrift for A. E.
Bergtes. R. M. Manglik and A. D. Kraus (eds.), Begell House, New York.
1996.

heattransfer engineering

importance of properly designing an experimental setup
to obtain the desired data by carefully controlling andlimiting the influence of extraneous variables. The approach taken by Professor Bergles shows the thoroughness he applies in the design of the entire study covering a specific topic. As seen from his studies on twisted
tapes, turbulators, microfins, and porous coatings, toname a few, he first considered a list of alternatives,
and then narrowed it down to specific configurations
through broad experimental investigations. This wasfollowed by well-thought-out experiments to reveal themost important parametric trends for the targeted configuration, an art he has displayed time and again. Fromthese parametric studies, he has provided specific directions to researchers in academia as well as in industry.
A list of research publications by Professor Bergles
published through December 1996 is included under
the list of references.' The articles are classified into
10 categories as shown in Table 1. The numbers in frontof a category indicate the article reference numbers.

"The list of references is in a slightly different format. Since there aremany articles with the same authors in a given year of publication, thearticles are numbered and are listed in chronological order. The articles arc
referenced by these numbers in the table and the text (within square brackets).

vol. 19 no.3 1998

13

Table 1

Publications by Professor Arthur. E. Bergles in Different Research areas

Research area

References

Subcooled boiling with special emphasison cooling of high-nux components
Fundamental studies in enhanced
heat transfer

4, 5, 18, 25, 33, 43

Fundamental studies and reviewsof two-phase flow and heat transfer
Instability of two-phase flows
Heat transfer to laminar internal flows
Flow and heal transfer of refrigerants(including evaporation and condensation, pure and oil-refrigerant mixtures)
Reviews of enhanced heal transfer

Studies and reviews of coolingof electronic components
General heal transfer
History of heat transfer

6, 8, 10, 16, 17,24,30,36,40,45,47,51,53,56,59,62,64,67,76,80,85, 90, 91, 93, 99,
103, 104, 114, 115, 116, 117, 123,127,128,130,136,138,139,145,147,148,152,155,
156,157,160, 161, 164,165, 171,172,180,181,182,191.192,193,194,196,199,205.
209, 212, 213, 214, 215, 222, 224, 225, 226, 228, 230, 231, 232. 233, 235, 236, 237, 238,
239,246,249,250.251,252,258,261,264,265,267,268, 270, 273, 275, 277, 278, 279,
281,282,287,288,289,290,292
9, II, 12, 15,20,21,22,26,27,28,32,39,50,60,70,72,73,79,96, 97.100,107,112, 126,
131,135,143,144,146,166, 188,195,241,248,253,254,257,259,260,263.266,269,
280,283,293,294,295
7, 13,29,31,37,38,42,44,46,48,54,71,98
23,34,41,57,61,65,69,83,106,108,118,119,120,125, 129, 198,286.298
158,159,170,175,183,185,187,192,204.206,207,208, 210, 242. 243, 271, 284(Papers on enhanced lubes covered under fundamental studies in enhanced
heat transfer)19, 35, 49, 52, 66, 74, 78, 84, 86, 88, 89, 92, 94, 95, 101, 102. 105. 109, 110, III, 113, 121,
122, 132, 133, 134. 137. 141, 142,149,151,153,154,173,189,223,229,255,276,291,
296, 300
68,81,82,140,150.162.163,166,167,168,174,176,177, 178,200,201,202,203,218,
219,220,234,245,256.262.272,274,299
1,2,3,14,55,58,63.75.87. 169, 184,190,197,216,217,221,227,240,244,247,285.297
77.124,179,186,211

REVIEW OF RESEARCH IN SPECIFIC AREAS
Table I covers all 300 articles published by Professor
Bergles until the end of 1996. The following review
presents the highlights and some important details andrelevance of his work. Due to space constraints, all thearticles listed in Table I could not be discussed. Although figures and tables are not included here, thereaders can identify the relevant articles from the information presented here, and then refer to those articles'for additional detai Is.

cost, and performance evaluation criteria for their selection. He undertook the task of identifying the underlying heat transfer and pressure drop mechanisms (for internal enhancement techniques) for these enhancement
devices, and provided insight that led to further improvements. Vibration, ultrasonics, twisted tapes, bentstrip inserts, finned tubes, microfin tubes, microporous
surfaces, microstructured surfaces, and stepped andwavy surfaces are among the enhancement techniques
he investigated, providing a rich wealth of experimental
data and a better understanding of the heat transfer
mechanisms associated with these devices.

Enhanced Heat Transfer

Single-Phase Enhancement

Professor Bergles has been one of the most active
proponents of enhanced surfaces in heat transfer applications. He has displayed vision in recognizing theimportance ofenhancement in refrigeration, power, process, and microelectronic cooling applications. In his
1979 article on energy conservation via enhancement(Bergles et al. [93]), he outlined the steps needed fordeveloping enhanced surfaces for commercial applications. As stated in his article, "Commercialization
represents the ultimate stage of development; however,even commercial products require additional development work." He was among the first to address comprehensively issues related to the application of enhanced
surfaces-fouling, manufacturing and development

Vibration and Additives. Mechanical vibrations effectively cause localized pressure fluctuations in the liquid adjacent to a heat transfer surface. When the liquid
is close to its saturation temperature, enhancement ispossible due to nucleation and collapse of bubbles. Professor Bergles became interested in this technique whileworking on the cooling of high-field electromagnets at
the National Magnet Laboratory at MIT (Bergles [6]).
To enhance the heat transfer to water flowing in the cooling channels, the channel walls were subjected to vibrations. The localized instantaneous reduction in pressure during a cycle resulted in cavitation in the water at
the channel walls. For wall temperatures of about 30°C
below the saturation temperature, the single-phase heat

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vol. 19 no. 3 1998

transfer coefficient remained unaffected. However, as
the wall temperature approached the saturation temperature, the heat transfer coefficient gradually increased,yielding up to 100% increase. The enhancement was
reduced as fully developed boiling conditions were established at higher wall temperatures. The effect ofultrasonic vibrations was tested further (Bergles andNewell [8]) with water flowing in annuli. The authors
provided experimental results in parametric form toshow the effect of system pressure, annulus dimensions,vibrational intensity, and wall superheat. The presenceof vapor in the flow channel drastically reduced theenhancement, indicating the applicability of this technique only to the subcooled region. The tubes were direct electrically heated in the experiments, a techniquethat Professor Bergles used extensively later with his
in-tube research work to obtain local heat transfer data.
Twisted- Tape and Other Inserts, and Internally Finned Tubes. Mechanical inserts and internal fins affectthe fluid flow field and the associated heat transfer process directly. Twisted tapes and other in-tube inserts
have been a major topic of Professor Bergles' researchon enhanced heat transfer since 1969. In his first article
on this topic, he reported a detailed experimental study(Lopina and Bergles [16]) on heat transfer and pressure drop with twisted-tape inserts with water in fully
developed turbulent flow. The enhancement, as muchas 100%, was attributed primarily to the increased flow
path, the increased circulation, and the tape fin effect.
An additive model was proposed to predict the heattransfer coefficient from these mechanisms. The contribution to heat transfer due to fin conduction was shown
to be small, about 8-17%, for perfect contact between
the tape and the wall. For a constant pumping power,
twisted-tape inserts provided a 20% improvement inheat transfer over an empty plain tube.
Surface roughness and twisted tapes both provide enhancement, although the mechanisms in the two cases
are different. The effect of combining these two techniques was investigated (Bergles et al. [24]) in the turbulent region. Since the two mechanisms do not overlap,
the combination was expected to provide further improvements, as was indeed the case. The superposition
technique worked well for correlating the heat transfer data in spite of the highly nonlinear nature of themechanisms. This helped to clarify the discrepancies
between two twisted-tape data sets obtained with thesame geometry-attributable to the differences in thesurface roughness of the tubes.
The effect of brush and mesh-type inserts was alsostudied experimentally (Megerlin et al. [53]) for highheat-flux applications. Both inserts yielded dramatic
improvements in heat transfer coefficient, up to 1,000%
heattransfer engineering

increase, as compared to plain empty tubes. However,the pressure drop penalty was extremely high, up to
20 times higher in certain cases.
Internally finned tubes are another form of enhancement technique tested extensively by Professor Bergles(Bergles et al. [36]). The heat transfer performanceof eight internally finned tubes was obtained experimentally under turbulent flow conditions. The effect ofroughness was found to be insignificant for the internally finned tubes tested. These tubes showed promise
for a heat transfer performance improvement of 25170% for a given pumping power.
The twisted tapes were tested for augmentation in thelaminar flow region (Hong and Bergles [64]), where a
1,000% enhancement in Nusselt number was confirmedwith water and ethylene glycol, covering Prandtl number ranges of3-7 and 84-192, respectively, with the two
fluids. The experiments were conducted for uniformheat-flux boundary conditions in a 10.2-mm electrically heated stainless steel tube employing twisted tapeswith twist ratios of 2.45 and 5.08. Hong and Bergles[64] developed a correlation scheme for heat transfer and pressure drop that was later extended to nonNewtonian fluids (Manglik et al. [222]). The work ofHong and Bergles [64] was extended to include static
mixer inserts and internally finned tubes (10 longitudinal fins, 1.57 mm height, in a 14.2-mm tube) for processindustry applications (Marner and Bergles [90]). These
devices were found to provide a higher heat transfer enhancement ratio compared to the pressure drop penalty
in the laminar region as compared to the turbulent region,
where increases in pressure drop were significant. The
study was extended to laminar flow with Polybutene 20(a liquid polymer manufactured by Chevron ChemicalCo., Prandtl number range 1,260-8,130) by Marnerand Bergles [147]. It was found that the internally finned tubes yielded a 400% increase in heat transfer
coefficient for heating, while the twisted-tape inserts
were more effective for the cooling applications, yielding 150-225% improvements over plain tubes. The internally finned tubes yielded only marginal improvements during cooling.
The twisted-tape insert results were analyzed(Manglik and Bergles [182]) in an effort to develop
a correlation to predict their performance with laminarflow under uniform-wall-temperature conditions. The
experimental data on heat transfer indicated a strong
influence of five parameters: entrance effect, fluid viscosity ratio (bulk to wall conditions), Prandtl number,tape twist ratio, and swirl-flow Reynolds number. The
augmentation of highly viscous laminar flow under constant-wall-temperature conditions was investigated insubsequent articles (Marner and Bergles [231]; Manglik

vol. 19 no.3 1998

15

and Bergles [261 D, in which extensive experimental
data on heat transfer and pressure drop were reported.
The available experimental data for water, ethylene
glycol, and Polybutene 20 obtained in earlier studies
were correlated within ±25'70 (Manglik and Bergles[182]). However, this correlation covered a limited
range of parameters. In subsequent articles, Manglik
and Bergles [264, 265, 277] presented mechanistic parameters to identify the effect of swirl on the flow field.
The balance of viscous, convective inertia, and centrifugal forces is used to predict the onset and intensityof swirl, as determined by the swirl parameter. Basedon this mechanistic description, four regions are identified: viscous flow, thermally developed swirl flow,
swirl-turbulent transition, and fully developed turbulent swirl flow. A continuous correlation covering theseregions for uniform-wall-temperature conditions wasdeveloped. The correlation accurately represents theparametric trends, as well as the asymptotic values fordifferent variables.
Spirally Grooved (Rope) Tubes. With the large amount of heat transferred in power plant surface condensers, tube-side enhancement of the heat transfer coefficient could result in considerable savings in overallplant operation. Spirally grooved tubes hold the promiseof enhancing the heat transfer coefficients on both sides;
they are one of the most cost-effective enhancement
devices. Professor Bergles saw the need to develop agood correlation scheme for these tubes for design purposes. Rabas et al. [212] compiled a data bank of 458
data points from five di fferent sources. They proposeda new correlation scheme to predict the heat transfer coefficient and friction factor for spirally grooved
tubes with an overall average error of less than 10%
with the existing data. This represents one of the mostcomprehensive correlation schemes that accounts forthe geometric factors and fluid characteristics. One of
the benefits of this correlation is that it is possible to see
clearly the parametric influences of different geometricparameters on the performance. It also serves as a valuable tool to the designer who is faced with the selectionof an optimum geometry based on not only the thermal,
but also economic and manufacturing constraints.
Turbulators for Fire-TIthe Boilers. Fire-tube boilers
employ high-temperature gases flowing inside tubes.
Since the heat transfer coefficient on the outside is very
high with boiling water, it is desirable to increase theheat transfer coefficient on the gas side. The overall
objective in this application is to improve the boiler
efficiency. Other factors, such as pressure drop, airfuel ratio, changes in the water-side heat transfer coefficient, fouling, and manufacturing cost are also important. In an experimental study program, Junkhan et al.
16heat transfer engineering[138] and Bergles et al. [145] investigated three commonly employed turbulators in fire-tube boilers (twobent strips and one twisted tape). The heat transfer enhancements for these three inserts were measured tobe J25%, 157%, and 65% over a plain empty tube,
while the corresponding increases in pressure drop were1,100%, 1,000%, and 160% at a Reynolds number of
10,700. The width of the twisted tape was less than the
tube diameter, and this contributed to the lowering of its
heat transfer enhancement to about 50% of the next best
tube, but the corresponding pressure drop was reduced
dramatically.
In order to identify the effect of the inserts on theflow characteristics in a fire-tube boiler application,
Nirmalan et al. [161] conducted visual studies on sevendifferent bent-strip types of inserts. The heat transfer
enhancement was measured to be between 175% and285% at a Reynolds number of 10,000, with corresponding pressure drop increases of 400% to 1,800%. The
visual observations indicate that the flow disturbance ismost severe in the region where the bent strip comes incontact with the tube wall. The flow remains relatively
intact in the region where the bent strip does not touch
the wall. Increasing the number of contacting points appears to increase the heat transfer coefficient, but with afurther penalty in pressure drop. The perforated-strip insert indicates that the core region also plays an importantrole in the heat transfer mechanism. The effect of radiation between the strip in the core region and the wall was
also seen to play an important role, warranting further
studies on this aspect. In a subsequent study, Nirmalan
et al. [164] tested three additional inserts. They also addressed the issues raised in their earl ier investigation(Nirmalan et al. [161]) by constructing separate inserts
representing the core region and the wall region of thebent-strip insert. The results indicate that inserts withmore rounded bends have a higher heat transfer coefficient as well as a higher pressure drop penalty. The pitch
was seen to play an important role in the entrance region.
The core-region insert was shown to enhance the heattransfer much more than the wall-region insert, contrary
to the earlier assumption that the core may not playas
important a role. However, the combined effect of the'two regions could be different from the individual influence of each region. Nirmalan et al. [180] presented
a theoretical model using a surface renewal/penetration
concept to develop a correlation scheme for bent-strip
inserts. In this model, they assumed that a packet of
fluid is thrown toward the wall by the insert in the coreregion. This fluid is heated at the wall during a transient
conduction process. The correlation scheme incorporates a constant that is characteristic of the individual
insert.
vol. 19 no. 3 1998

Ravigururajan and Bergles [251] also visually investigated the flow phenomenon near the wall of ribbed
tubes. Flow visualization was seen as a useful tool in
optimizing ribbed geometries.
Twisted-Tape Inserts with NOll-Newtonian Fluids.
Non-Newtonian fluids are often encountered in the chemical, petroleum, food, biochemical, and pharmaceutical industries. Typical fluids in these applications are
paints, inks, soap and detergent slurries, polymer solutions, greases, bitumen, paper pulp, corn syrup, mayonnaise, and starch suspensions, which are pseudo-plastics.
The three basic mechanisms of augmentation, (1) secondary flow effects, (2) an increased flow path, and(3) fin effects, are still responsible for enhancement in
non-Newtonian fluids. Manglik et al. [222] conducted
an extensive study to investigate the heat transfer andpressure drop for laminar flow of non-Newtonian fluids in uniformly heated tubes with twisted-tape inserts.
The experiments were conducted with two concentrations, 1.0% and 1.3% of HEMe solution in a 12.85rnm-diarneter stainless steel tube. They attributed theincrease in heat transfer coefficient with pseudo-plastics
in single-phase flow to (1) the non-Newtonian effects,and (2) the variable consistency effects. Using the same
correction factors, the Hong and Bergles [64] correlation for the uniform-heat-flux boundary condition was
modified to predict the heat transfer results within±30%. This is quite remarkable, considering that Hongand Bergles [64] could predict their own water andethylene glycol data only to within ±25%. Similar treatment resulted in a reasonable agreement with pressure
drop data as well (+25% to -30%.)Natural Convection. Natural-convection heat transfer is an important mode of heat transfer employed inmany applications including cooling of microelectronic
devices. It is desirable to extend the applicability ofnatural convection to avoid the need for an active device
such as a fan or a blower in the cooling system. Augmentation of natural-convection heat transfer, therefore,
has received renewed interest in the last decade.
A systematic study was undertaken by Professor
Bergles to investigate augmentation of natural-convection heat transfer. Bhavnani and Bergles [157, 239]
conducted an interferometric study of the laminar-convection heat transfer process from an isothermal verticalplate with two types of transverse elements, transverse
ribs and transverse steps, placed horizontally across a
127-1010 x 178-1010 aluminum plate. A Mach-Zehnderinterferometer was used for taking local measurements.
The effects of pitch, height, and width (in the case ofribs) were investigated. It was found that the transverse ribs, in fact, decrease the overall heat transfer
rate by creating stagnation zones on both the upstream
heat transfer engineeringand downstream sides of the ribs. The stepped surfaces helped to improve the performance. Bhavnani
and Bergles [213, 252] studied the effect of a sinusoidal wavy surface on heat transfer. This geometry
resulted in average heat transfer rates very close to plainsurface values. An effect of wave amplitude was seen in
the results. Smaller amplitudes caused the transition toturbulence at lower Grashof number values of around2 x 107 as compared to a plain vertical surface. It was
found that if the lower edge of the plate was curved
inside, this resulted in a better performance; however,this effect was not significant when two or more cycles of the wavy surface were present along the plate
length.
Fouling in Enhanced Surfaces. Fouling in heat exchanger tubes is a major issue that needs to be addressed
before enhanced tubes can be employed, especially in
critical applications such as utility condensers. With
this objective, Somerscales et al. [250] and Bergles
and Somerscales [290] carried out an extensive testing
program on tubes employing four types of enhancement techniques, namely, roped or corrugated, helicalfins, axial fins, and helical rib roughness. They conducted the tests with magnesium oxide (approximately
3 /Lm diameter) as the foulant suspended in distilledwater. The tests showed that tubes with axial fins, helical fins, and rib roughness exhibited a higher fouling rate than a smooth tube under both high-velocity
and low-velocity tests, whereas roped or corrugatedtubes showed a remarkably lower fouling rate. However, Bergles [273,278] reported a review of other workin which the field testing of roped or corrugated tubes
showed considerably higher fouling rates with river andsea water. They attributed the main reasons for this discrepancy to the differences in the nature of the fouling elements present in the laboratory testing and thefield testing. The water in the field tests contained dissolved salts, biological substances, finely divided sandor silt, and other products of chemical reactions, while
the laboratory tests were conducted with a single
foulant.
Performance Evaluation Criteria for Single-Phase
Enhancement. Thermal equipment designers are often
faced with the task of selecting an appropriate enhancement device for a given application. Many researchers were working on developing guidelines to help
in this selection process during the 1960s and 1970s.
Bergles [19] presented a comprehensive survey of different augmentation techniques, and identified the needto establish generally applicable selection criteria foraugmentative techniques. Factors such as development
cost, initial cost, operating cost, maintenance cost, reliability, and safety are important in this selection process,vol. 19 no.3 199817

but are too difficult to evaluate for general application. The enhancement ratio in heat transfer coefficient,at constant pumping power, length, and diameter, wasused to compare different single-phase enhancement
techniques. In a subsequent article, Bergles et al. [45]proposed eight performance evaluation criteria for augmentation devices. The parameters used in these criteria
are basic geometry, flow rate, pressure drop, pumping
power, and heat duty, while the three possible objectives
considered are increased heat transfer, reduced pumping
power, and reduced heat exchanger size. With these parameters, the following eight criteria were proposed: (1)for fixed geometry and flow rate, increased heat transfer;(2) for fixed geometry and pressure drop, increased heattransfer; (3) for fixed geometry and pumping power, increased heat transfer; (4) for fixed geometry and heat
duty, reduced pumping power; (5) for fixed heat duty
and pumping power, reduced exchanger size; (6) for
fixed heat duty and pressure drop, reduced exchanger
size; (7) for fixed heat duty and flow rate, reduced exchanger size; and (8) for fixed heat duty, flow rate, andpressure drop, reduced exchanger size. Bergles et al. derived specific ratios for each criterion. To include economics, a ninth criterion was introduced by comparing
the total annual cost with, and without, augmentation.
These criteria have been extremely helpful in convincing the heat exchanger industry of the potential benefitsof switching to enhanced geometries.
Bergles et al. [59] further modified the performance
evaluation criteria to remove the assumption of constant temperature difference between the hot and cold
streams, and to include the effect of the thermal resistances external to the enhanced surfaces. Bergles et al.
[62] applied these criteria in the selection of compact
heat exchanger surfaces. Webb and Bergles [123] presented algebraic formulations of these criteria for lowReynolds-number flows. These criteria are now widelyused in the development and selection of compact heatexchanger surface geometries in automotive, air separation, and many other industrial applications. Applying these criteria to the bent-strip inserts in fire-tube
boilers, Webb and Bergles showed that a favorable enhancement is achieved in the Reynolds number range of
5,000 to 30,000 under a constant-pumping-power constraint, while the range drops to between 3,000 to 5,000
under the constant-pressure-drop constraint.

Enhancement in Pool Boiling
Vibration and Ultrasonic Techniques. The instantaneous reduction in pressure in the liquid adjacent to aheated surface leads to rapid growth and collapse ofvapor bubbles, resulting in enhancement in subcooled
18

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pool boiling. Such effects of vibration on subcooledpool boiling heat transfer were studied by Bergles [17]with water as the working substance. An increase invibrational energy markedly increases the pool boilingheat transfer rates. Also noted was the effect of vibrationon the CHF.
Park and Bergles [199] studied the effects of ultrasonics on the heat transfer performance of a smooth poolboiling surface for possible microelectronic cooling applications. They used refrigerant R-l 13 as the test fluid.
The results obtained were similar to those obtained by
Bergles [17] in that little enhancement was observed
for saturated conditions. Enhancement improved with
subcooling. Burn-out heat fluxes were not significantly
altered with ultrasonics.
Low-Finned and Modified Structured Surfaces. The
meticulous work by Professor Bergles in revealing thenature and mechanism of nucleate boiling in enhanced
surfaces has been outstanding. He combined experimental measurements with visual techniques in revealing the flow of liquid in rnicropores and channels ofenhanced boiling surfaces. His work provided a clear
direction for industry in improving the performance ofenhanced pool boiling surfaces.
Low-finned tubes were used in pool boiling applications from the I940s. New surfaces with porous coatings and modified low-finned tubes were manufactured
commercially under names such as High Flux, ECR40,
Therrnoexcel-E, and GEWA-T. The standard GEWA-K
profile is a low-finned surface, while GEWA-T is a modified surface in which the GEWA-T fins are formed
into a T-shape by indenting a notch in the tip of the
fin and then press-rolling the tip. To understand themechanisms responsible for the higher performance of
the GEWA- T surfaces, Ayub and Bergles [156, 181]
conducted an experimental study to compare the poolboiling heat transfer rates for GEWA-T and GEWA-K
surfaces. Both surfaces showed more enhancement with
R-113 than with water, (maximum enhancement of
100% and 60%, respectively, with R-113 and water).
One of the highlights of the performance of these tubes
was the lack of a temperature overshoot at the onset of
nucleate boiling. Comparing the performance of various geometries, Ayub and Bergles observed that the gap
width between the fins was an important parameter inthe thermal performance. The performance of a particular geometry was dependent on the fluid employed-so
the idea that each geometry needs to be optimized forspecific refrigerant was proposed. The study of the flow
pattern near the boiling surface revealed that a predominant pattern of liquid inflow was present at different
locations. Liquid entered the finned surfaces at specificlocations, while bubbles were generated at both sides
vol.19 no.3 1998

of these locations. A continuous liquid-vapor exchangemechanism, different than the ones reported before forpool boiling, was observed for these surfaces. Ayub andBergles proposed a heat transfer model which suggested
that the heat transfer in this geometry is controlled by latent heat transport and agitated natural convection. Professor Bergles recommended that this study should be
extended to CHF, and the performance of this geometry
studied in tube bundles. This study represents a major
step in the understanding and subsequent developmentof enhanced surfaces in pool boiling applications.
To enhance the performance of a GEWA- T surface
further, Ayub and Bergles [196] proposed filling the gap
between the fins with a sponge material, polystyrene
di-vinyl benzene polymer. The presence of the sponge
was expected to increase the bubble activity in the gap.
The pool boiling experiments were conducted on thesefilled surfaces with distilled water. Experimental results
showed that the heat transfer rates increased by a factorof 1.5 to 2.3 relative to GEWA-T tubes with unfilledgaps.
Boiling hysteresis is caused by the fact that the superheat needed to activate a cavity is higher than that
required to keep it active after it has been activated.
Its effect is pronounced at the onset of nucleate boiling, when the higher superheat requirement may cause
the surface to overheat considerably before the poolboiling is established. Also, a vigorous explosion on
the heating surface accompanies the onset of nucleateboiling in certain cases. The effects of hysteresis wereseen to be a major problem in utilizing pool boiling inelectronic cooling applications. Ayub and Bergles [214,237] conducted an experimental study to characterize
the hysteresis for GEWA- T surfaces. These surfaces exhibited a small but different kind of hysteresis in which
multiple smaller excursions in wall temperature wereobserved during the transition from natural convection
to nucleate boiling. They attributed this to improved
natural convection in the low-finned surfaces prior to
nucleation. The multiple excursions were believed tobe due to the isolation of nucleation sites from one another in the helical grooves.
Bergles and Chyu [104, 117, 127] presented a study
focusing on the hysteresis effect of structured surfaces
in pool boiling. They showed that tubes coated externally with porous metallic coatings showed considerable nucleate boiling enhancement once nucleate boiling was initiated. However, similar to smooth tubes. theenhanced tubes tested showed a hysteresis effect thatwas not reported in any earlier literature. The hysteresis
was attributed to the wetting and flooding of the cavities by the liquid, particularly for refrigerants. Bergles
and Chyu [127] discussed the problems encounteredheattransfer engineeringby temperature overshoot in different industrial applications. The effect of pore size and the heat transfer
mechanism in tunnels formed by the microstructures
were discussed by Bergles [215] in a comprehensive
article on this subject.
Professor Bergles extended the study of nucleate boi ling with water on enhanced surfaces to pure refrigerants
R-113 and R-l1 and their binary mixtures as reported by
Trewin et al. [282]. The tubes tested included smooth,knurled (Turbo-B), and sintered (High Flux) surfaces.
Nucleation on these surfaces was initiated in some caseswith a wall superheat of less than 0.1 "C. They hysteresis effect was most pronounced for small-porosity High
Flux surfaces, resulting in an overshoot of 10°e. The
porosity of the High Flux surface played a major rolein the heat transfer process. Smaller-porosity tubes performed the best (after nucleate boiling was initiated following the hysteresis effect) among all the tubes tested.
Another major conclusion of the study was that the sizesof the channel openings in Turbo-B tubes had very little influence on the heat transfer rate, indicating that thesubsurface channel itself plays an important role. Theseauthors identified thin-film evaporation inside the channels as the main heat transfer mechanism in the Turbo-B
tubes. The pool boiling heat transfer coefficients with
mixtures showed a degradation for all three surfaces,
although the enhanced surfaces consistently performed
better than the smooth tube. A need to develop better
correlating schemes for mixtures with enhanced surfaces was identified.

Enhancement in Two-Phase Flow,
Boiling, and Condensation
There is a need to improve the performance of heattransfer equipment incorporating boiling and condensation processes from an energy conservation viewpoint.
The benefits to the refrigeration, power, and processindustries would result directly from the overall conservation of energy resources. With the rapid advancements in enhancement techniques for single-phase heattransfer, it was only a matter of time before it was realized that further improvements in flow boiling andcondensation heat transfer rates are warranted to improve the overall efficiency of thermal systems. Professor Bergles addressed this need by conducting extensive
research on enhancement in flow boiling and condensation.
Doubly Rippled Surface for External Condensation.
One of the most important factors in determining theexternal condensation heat transfer is the existing film
thickness on the condensing surface. This layer presents
a thermal barrier to heat transfer. In applying the pool

vol. 19 no.3 1998

19

boiling mode to electronic cooling, efficient condenser
surfaces were needed to transfer the heat from the condensing refrigerant to the cooling water. In 1972,
Markowitz et al. [47] developed a doubly rippled surface, the main ripples help to drain the condensate film
effectively from the downward-facing condenser surface; while the secondary ripples reduce the film thickness on the condenser surface between the main ripples. An analytical formulation was presented to predict
the thermal performance by extending the laminar film
condensation theory. Although the experiments yielded
lower heat transfer rates than predicted by the theory, anumber of practical problems arising in such research
work were pointed out. These include proper degassing
procedure the effect of noncondensables, and the assumption of nonuniform heat flux over the condensing
surface.
Twisted Tapes. Internally Finned Tubes, Wall Roughness Elements, and Microfins for In-Tube Evaporation
and Condensation. The work of Professor Bergles on
twisted tapes in single-phase flow has provided an insight into the heat transfer mechanism, and a powerfulcorrelation technique along with invaluable experimental data for this geometry. Professor Bergles saw thepotential of twisted tapes in in-tube condensation application, and undertook a detailed study to explore
this field. Although many investigators studied condensation enhancement techniques, Professor Bergles
pointed out that very few efforts were directed toward
in-tube enhancement.
Royal and Bergles [67, 85] conducted a detailed experimental study on the augmentation of in-tube condensation of low-pressure steam in horizontal tubes
by means of twisted tapes and internally finned tubes.
Twisted tapes showed an improvement of 50%, while
the internally finned tubes showed an improvement of
300%, in heattransfer rates over empty smooth tubes. To
make the data useful to practitioners, Royal and Bergles
presented correlations for both geometries, using theirown data as well as other data available in literature.
The work on in-tube condensation with water was
extended to refrigerants by Luu and Bergles [99] for application in refrigeration and air-conditioning. Twisted
tape inserts and three different internally finned tubes
were tested. Internally finned tubes performed better
than twisted tapes. Using performance criteria with aconstant pressure drop, internally finned tubes were by
far superior, and held promise in commercial applications. Professor Bergles, however, pointed out that thefin geometries resulting in optimum performance forrefrigerants are different than those for water. Luu andBergles [103] presented qualitative reasons for the differences in condensation characteristics of water and20

heat transfer engineering

R-113. The important parameter is the condensate film
thickness, which depends on the surface tension, thedensity ratio of the two phase, and the wall shear stress.
Twisted tapes were seen as possible retrofit devices inexisting condensers.
Wall roughness elements, such as helical repeatedribs and spirally fluted tubes, were found to be effective in enhancing single-phase heat transfer. Professor
Bergles investigated their performance for in-tube condensation. Luu and Bergles [114] and Bergles [139] reported that their experimental study of helical repeatedribs and spirally fluted elements yielded 80% and 50%
enhancement in heat transfer coefficient over a smoothtube. Correlations for these geometries were proposed.
The use of microfin tubes for condensation applications was studied extensively by Professor Bergles.
Khanpara et al. [171] compared the performance of one
plain and eight microfin tubes for in-tube condensationof R-113. The heat transfer coefficients were improved
considerably over those for smooth tube values. The
main reasons for the enhancement during condensation
were identified as the area increase due to fin effect,thinning of the condensate film, and the disturbances
caused by the presence of fins. The effects of fin shape,
fin height, number of fins, and spiral angle were discussed. This information proved useful to manufacturers in the design of new and more efficient microfin
geometries.
Microfin tubes were at that time being introducedin the refrigeration industry, and with relatively little
flow modification in the bulk flow, they offered a highheat transfer coefficient coupled with a low pressuredrop penalty for evaporators as well. Khanpara et al.
[165] conducted an extensive study on one plain andeight microfin tubes of different geometry to arrive at
the optimum-performing tube. They conducted experiments in electrically heated test sections over a rangeof quality, mass flux, and heat flux. The results clearly
identified the tube that performed best for refrigerant R113 over the given range, and changes in the microfin
geometry were proposed based on the observed trends.
Khanpara et al. [183] also conducted a study comparing electrically heated and fluid heated test sections
during evaporation of refrigerant R-113 in smooth andmicrofin tubes. The heat transfer coefficient was thesame for the two cases at low and medium mass flow
rates; however, the high mass flux rates, the electricallyheated long test section gave 20---40% higher heat transfer coefficients. Further investigation is needed in thisarea.
Comparing various enhancement techniques proposed in the literature, Professor Bergles conducted asystematic study to evaluate their performance withvol. 19 no.3 1998

refrigerants. Reid et al. [191,249] compared the performance of five microfin tubes, and a smooth tube
with a twisted-tape insert, with the performance of two
different-diameter smooth tubes. The heat transfer coefficients and pressure drops were obtained for thesegeometries over a wide range of quality, mass flux, andheat flux. This work showed that microfin tubes with ahelix angle around 16-18° performed well, with a low
increase in pressure drop.
The effect of fluid properties on the performance of
microfin tubes of different geometries is an importantarea in refrigeration applications. Khanpara et al. [192]compared the performance of different microfin tubes
with R-113 and R-22 refrigerants over the range of operating conditions commonly encountered in refrigeration
practice. The enhancement in heat transfer was similar
with the two refrigerants in the high-mass-flow region.
In the low-mass-flow region, enhancement was higher
with R-113. Khanpara et al. emphasized the need to develop a correlation scheme for microfin tubes. Schlager
et al. [230] present a detailed study on evaporation andcondensation heat transfer in microfin tubes with R22. The microfins showed considerable enhancements(factors of 2.3 to 1.6 for evaporation, and 2.0 to 1.5 forcondensation). Corresponding pressure drop increases
were only 20-40%. The effect of tube diameter on
the performance was insignificant. This work showedthat a microfin geometry could be applied to differentdiameter tubes without any modifications. These studies
clearly indicated the superior performance of microfin
tubes in boiling and condensation. It is therefore no surprise to see their widespread use in the refrigeration andair-conditioning industries.
The performance of several microfin tubes in a fluidheated test setup was tested with refrigerant R-22 bySchlager et al. [225]. The tests indicated that the performance of all microfin tubes appeared to be close
together. An increase in mass flow rate decreased evaporative performance. The pressure drop penalty was lessthan the heat transfer increase, but it increased with increasing mass flow rate.
In practical applications, a small amount of oil isgenerally present in the evaporators and condensers ofa refrigeration system. Schlager et al. [204] present a
detailed study of the effect of oil on the evaporation andcondensation heat transfer in a low-fin tube. Refrigerant
R-22 was used with a ISO-SUS naphthenic mineraloil. Small amounts of oil, below 1.5% led to an improvement in the evaporative heat transfer coefficientfor smooth tubes, but the low-fin tube showed very little enhancement. Larger quantities of oil degraded theevaporator performance for the low-fin tube below thesmooth-tube level. The condensation performance washeattransfer engineering

degraded with the presence of oil, but it was less adversely affected compared to smooth tubes. The work
showed clearly that the presence of oil in refrigeration
systems affects the thermal performance of augmented
tube evaporators and condensers.
A similar study was conducted by Schlager et al.
[209] to investigate the effect of oil on the evaporationand codensation heat transfer for smooth and microfin
tubes. As found in earlier studies, the presence of oil
improved the evaporation heat transfer coefficient ofsmooth tubes. Microfin tubes exhibited similar trends,
although the enhancement was less. The condensation
heat transfer coefficient decreased with an increase in oi I
concentration for both tubes. Schlager et al. [209] also
discussed specific effects of oil concentration and massflux. Subsequently, Schlageret al. [224,233] found thatthe effects of 300-SUS oil were similar to those with
ISO-SUS oil.
Schlager et al. [228, 238] presented results showing the effect of oil on the heat transfer and pressure
drop performance of smooth and internally finned tubes
with R-22. The performance trends for the finned tubes
were similar to those for the microfin tubes, but wereconsistently below those for the microfin tubes. Duringcondensation, both enhancement techniques resulted inlower heat transfer rates, as compared with the smoothtubes with the addition of oil.
Schlager et al. [235,236] conducted a detailed literature survey and presented design correlations for predicting the heat transfer coefficients with refrigerant-oi I
mixtures during evaporation and condensation insidesmooth and microfin tubes. These correlations are extremely useful to designers of heat transfer equipment.
The mechanisms responsible for degradation of heattransfer performance in microfin tubes with oil were notclearly understood, so Ha and Bergles [270] conducteda careful study to investigate the effect of oil using visualobservations and careful mass fraction measurements inthe liquid film near the wall. They found that an oil-richlayer adhered to the wall, and its thickness increased
with oil concentration and mass flow rate. They identified the thermal resistance of this layer as the primaryreason for the performance degradation.
Twisted Tapes in Dispersed-Flow Film Boiling. The
swirl flow generated by twisted tapes could be effective
in modifying the film flow and heat transfer behavior
in the dispersed-flow film boiling region. Bergles et al.
[30, 40] conducted an experimental study to validate
these findings experimentally. Their results show thatup to 200% enhancement is possible with the introduction of a swirl generator in the flow. In this work,
Professor Bergles also considered the practicality ofthe enhancement device by studying its performance

vol. 19 no.3 199821

under a given pressure drop or pumping power condition. Assuming that swirl flow promotes thermal equilibrium in two-phase flow, a model was proposed that
requires only one "adjustable constant," the fraction of
the tube wall covered by the centrifugal droplets. Withan optimized constant, the correlation described the datawell.

Enhancement in Film Evaporation
Horizontal spray-film evaporators are employed indesalination, refrigeration, and chemical process operations. Their applicability to ocean thermal energy
conversion systems was evaluated by Chyu et al. [130].
Since ocean thermal energy systems work between small
temperature differences, improving the performance ofthe evaporation and condensation processes in the power
cycle is critical. In the evaporator, the nucleate boilingin the film would be important, and porous and microstructures, employed in pool boiling enhancement,
are strong candidates. Chyu et al. tested five surfaces
and found a considerable improvement over smoothsurface performance. However, the performance withspray was below the corresponding pool boiling performance for these surfaces. They attributed the main
reason for the poor performance to the unfavorable temperature profiles in the film.
Enhancement with structured surfaces in falling-film
evaporators was investigated by Chyu and Bergles [148,232]. The surfaces tested included a smooth, WielandWerke Gewa-T deformed low fin surface, Hitachi
Thermoexcel-E tunnel-pore surface, and Union Carbide
Linde High Flux porous metallic matrix surface. Fallingfilm evaporation over smooth surfaces yields higher
heat transfer coefficients than the corresponding poolboiling values. The falling-film results for structured
surfaces approach the pool boiling results over structured surfaces at high heat fluxes. Distinct effects wereseen in the convective and nucleate boiling mechanisms,
depending on the surface tested. Effects of film flow rateand liquid feed height were of secondary importance.
The need was emphasized to investigate structured surfaces with different fluids for specific applications.

Review Articles 011 Enhanced Heat Transfer
One of the most significant contributions to the technical community made by Professor Bergles is inproviding state-of-the-art reports in many areas, including enhanced heat transfer. He started his work in thisarea in the early 1960s, and is still in the midst of publishing various review articles.

22

heat transfer engineering

Professor Bergles' first elaborate review article on
augmentation techniques appeared in 1969 (Bergles[19]). He referenced 371 articles in this work, and classified them into the following categories: vortex flows,
including twisted-tape swirl generators; vibration of theheater surface; electrostatic fields; and various typesof additives. Nonboiling, boiling, and condensation infree and forced convection, and mass transfer in forced
convection were covered. The review included key information from various articles, and offered guidancefor practical applications by presenting turbulence promoter data in terms of a pumping power performance
criterion. Professor Bergles reported important experimental data in figures, which were carefully drawn to
include detailed information on the experimental conditions for which the results were presented. He compiled
and presented the experimental investigations in tabularform to bring out clearly their key features. Through thisarticle, Professor Bergles raised the standard for presenting state-of-the-art reviews, and he himself wrote
more than 50 such in-depth reviews on different aspectsof heat transfer.
To aid researchers in narrowing their search to specific articles, and to help designers find specific references in their field of interest, Professor Bergles started
preparing a bibliography of available literature on various topics. Bergles and Webb [35] presented the firstsuch bibliography on augmentation of convective heattransfer. It included references to 472 articles. Professor
Bergles then developed an extensive bibliographic collection, resulting in a six-part series co-authored withProfessor Ralph Webb-[86] and [92] in 1978, [94] and[95] in 1979, and [102] and [105] in 1980. Even with theavailability of on-line computer services, the exhaustive
bibliographic collections, presented under specific categories, are a valuable resource for researchers and designers, since a computerized search is able to capture
only a fraction of the available literature.
Professor Bergles kept pace with developments in enhanced heat transfer, and provided critical surveys, thatwere valuable in determining the potential of a given
augmentation technique for a specific application. He
has constantly updated his reviews on augmentation,and has published them periodically since 1969. Reviewing the augmentation of convective heat transfer,
he has authored or co-authored the following articles:
Bergles et a1. [49], [52], [66], [84], [88], [89], [109],[110], [III], [132], [149], [151], [173], and [189]. References [153] and [154], published in 1986, deal withenhancement in high-temperature applications. A majorpart of Professor Bergles' research activity has been
directed toward enhancement in boiling and condensation applications. He presented his first article in thisvol. 19 no.3 1998

area, Bergles [74], in 1976, and has steadily reported his
latest compilation of research work: [78], [134], [142],and [229].
Professor Bergles presented extensive review articles
on the effects of temperature-dependent fluid properties
on laminar-flow heat transfer [119, 120] and enhancement techniques in the laminar-flow region (Joshi andBergles [129]). In laminar flow enhancement, his reviews, Joshi and Bergles [113] and Bergles and Joshi[122], provide an extremely valuable resource for selecting a specific type of enhancement device, and understanding the underlying enhancement mechanism
occurring in it.
Professor Bergles classifies the enhancement techniques implemented in the last 20 years or so as secondgeneration heat transfer technology. Starting with thesmooth tube as the first generation, finned surfaces
and 2-D structured surfaces are classified as secondgeneration enhancement technology. Starting in 1983,
Professor Bergles has extensively reviewed the secondgeneration enhancement devices in the following
articles: Webb and Bergles [137], Bergles and Webb[141], [223], [255], [276], [291], and [296]. The current thrust of Professor Bergles' work, as described in
his recent articles Bergles [300], is toward the thirdgeneration enhancement technology that includes 3-D
roughness elements, 3-D fins, microfins, and metallic matrices. Although some of these techniques were
invented many years ago, their widespread acceptancein industrial applications really determines their"age."

Laminar Internal Flow
Professor Bergles started his work on laminar internal flow with an extensive study of the effect of naturalconvection on heat transfer, in fully developed laminarflow of water inside a tube, with uniform heat flux at thewall (Newell and Bergles [23]). This study included theeffects of circumferential variation in the wall temperature by considering two limiting tube-wall conditionsan infinite-conductivity tube, and a glass tube (having
the same thermal conductivity of the wall material as thetest fluid, water). At low Reynolds numbers, a secondary
flow due to natural convection is established, which issymmetrical about the vertical plane passing throughthe axis of the tube. The flow field is three-dimensionaland spiraling in character. The governing differential
equations employed stream functions, and were solved
using a finite-difference formulation. Results were presented in terms of detailed parametric relationships. To
make the results useful to designers, correlations for
Nusselt number, and a pressure drop parameter (friction
heat transfer engineeringfactor x Reynolds number) were presented as functionsof bulk temperature, heat flux, and tube radius. Computer limitations did not permit extensive solutions withsecondary flows in the entrance region. In a later technical note, Professor Bergles [34] discussed the applicability of different assumptions, such as constant wall
temperature, Prandtl and Reynolds number effects, andthe entrance region effect.
After analyzing the combined convection problem
analytically, Professor Bergles undertook experimental work to verify the numerical results. Bergles andSimonds [41] conducted experiments with electricallyheated, coated glass tubes, using water as the test fluid.
The final correlation, presented in graphical form, covered both the developing and the fully developed flow
regions. The heat transfer results were much higher(about three times higher for a Rayleigh number of
106 in the fully developed region) than the corresponding constant-property solution. In this work, Professor
Bergles showed mastery in designing experiments toobtain meaningful information regarding a phenomenon, while providing useful design correlations toengineering practitioners. We see this throughout his
experimental work in many different areas.
Hong et al. [57] extended the numerical and experimental work to combined convection in electricallyheated metal tubes. Their results agree with theoreticalanalysis; the results for the metal tube lie between theconstant-heat-flux and the constant-wall-temperaturecases. A correlation was presented for Nusselt number by including a parameter representing the ratio of
the fluid to wall thermal conductivities. Morcos andBergles [61] included the effect of variable properties
in the laminar fully developed region. The mean film
temperature, rather than a viscosity correction factor,
was employed to account for the property variations.
Hong and Bergles [69] presented analytical solutions
for combined convection with fully developed laminarflow in a circular tube by considering the temperaturedependent viscosity. The results were then correlated
in simple forms to cover a wide range of parameters.
The results with variable properties lie 50% above theresults for the constant-property solution.
To gain further insight into the heat transfer mechanism with twisted-tape inserts, Hong and Bergles [65]studied the laminar heat transfer in the entrance region of a semicircular tube with uniform heat flux.
They later employed the results of this work in themodels developed for twisted-tape inserts. Hong andBergles [83] presented analytical solutions for developing and developed flows, and showed that the heat transfer rate is increased by 200% and the entrance region is
reduced to one-tenth, by including the variable property
effects.

vol. 19 no.3 1998

23

Joshi and Bergles [106, 108, 125] analyzed laminarflow heat transfer in circular tubes, with uniform wallheat flux, for non-Newtonian fluids. They compared
the results of the analytical study with available correlations. Using their own experimental data covering abroad range of parameters, they presented two correlations based on the temperature dependence of the rheological characteristics of the fluid. Joshi and Bergles[118, 129] extended the study to the uniform-walltemperature case.
The articles by Professor Bergles on enhancement in
the laminar region are summarized in a later section.

Heat Transfer to Refrigerants (Boiling andCondensation Heat Transfer)
A major part of Professor Bergles' research work
has been directed toward the refrigeration industry. His
work on enhanced tubes (especially microfin tubes) for
boiling and condensation is noteworthy, and is covered
above. In this section, his work on other aspects of heattransfer to refrigerants is discussed.
Although much of the research in academia is directed toward pure refrigerants, most refrigeration systems employ oil-refrigerant mixtures to provide lubrication to the compressor in the system. With fluorinatedhydrocarbon refrigerants, oil is soluble in the refrigerant, and is carried over from the compressor to the condenser and evaporator. Baustian et al. [158] reported
a study summarizing predictive methods for thermophysical and transport properties of Oil-refrigerant mixtures. To determine the oil concentration in the mixture,
Baustian et al. [159, 170] reviewed different electricaland optical properties as possible bases for real-timemeasurements. They recommended two types of measurements: capacitance measurement and refractive index measurement. Continuing this study into the experimental phase, Baustian et al. [206, 207, 208] built
and tested three concentration-measuring devices basedon density, viscosity, and acoustic velocity, respectively.
These devices provided practical solutions to the refrigeration industry for on-line measurement of oil concentrations.
Continuing with the practical problem of oil-refrigerant mixtures, Manwell and Bergles [242] presented anexperimental study of gas-liquid flow patterns with refrigerant R-12. They conducted the study with smoothand rnicrofin tubes. The presence of oil caused foaming,
which wetted the walls, and led to foamy slugs in theevaporator. This explains the improvement in the heattransfer coefficient for smooth tubes with the addition ofoil to pure refrigerants. Since the wetting phenomenon

24heattransfer engineeringis already present in microfin tubes, the presence ofoil does not necessarily improve the heat transfer. Further, Manwell and Bergles did not observe the foaming behavior in microfin tubes. This study seems to be
the first one to address the mechanism of enhancementwith oil-refrigerant mixtures in smooth and microfin
tubes.
The oi I concentrations in the evaporator and condenser play an important role in the heat transfer mechanism. Schlager et al. [243] measured these oilconcentrations as functions of heat and mass fluxes,
and exit superheat. As expected, with the exiting refrigerant closer to saturation, the oil concentration in
the evaporator increased. The experiments showed thatthe concentrations in the evaporator were as muchas three times and those in the condenser were about
twice the average concentration in the system.
Professor Bergles conducted extensive heat transfer
measurements in evaporators and condensers with oilin smooth and microfin tubes. This work is reviewed
above, under enhancement in two-phase flow.
Strati fication effects in horizontal evaporators cause
circumferential variation in heat transfer coefficient. Ha
and Bergles [271] conducted a detailed experimental
study to measure this variation as a function of othersystem parameters. The effect of axial wall conduction
influenced the heat transfer coefficient by only 10%. In
runs with clearly separated flow, the heat transfer coefficient at the base was three to five times higher than the
average value. The importance of liquid film for evaporation was confirmed, indicating severe deteriorationin heat transfer in the upper part of the tube exposed tovapor in the stratified flow.
Ha and Bergles [284] presented a valuable discussionof the effect of the type of heating on the heat transfer
mechanism in boiling systems. They compared electric
resistance wire heating, direct electric heating, and liquid heating, and listed advantages and disadvantagesof each method. The article provides valuable insight
into the heat transfer mechanism in smooth and microfin evaporator tubes, with pure refrigerant and oilrefrigerant mixtures. The dryout toward the exit of theevaporator is delayed with microfin tubes, resulting ina significant increase in the heat transfer performanceof these tubes.

Fundamental Studies and Reviews of Two-Phase
Flow and Boiling Heat Transfer (In eluding Boiling,
and Two-Phase Flow Instabilities)
Professor Bergles addressed many current issues in
two-phase flow, boiling heat transfer, and CHF undervol. 19 nO.3 1998

different configurations-pool boiling, subcooled flow
boiling, and saturated flow boiling. To cover his contributions, his publications in these two broad areas
are presented under the following specific subsections.

Two-Phase Flow Regimes and Flow Structure
Flow patterns in two-phase flow were studied byearly investigators with air-water, and oil-gas systems
under adiabatic conditions. To understand the heat transfer in high-pressure boilers used in the nuclear industry,
Bergles and Suo (9) undertook an experimental study
to identify the flow patterns under diabatic conditions.
They investigated the effect of tube length, system pressure, mass flux, and inlet subcooling in vertical upflow.
They identified the flow regimes primarily with an electrical resistance probe. They also took high-speed still
pictures, but the resistance probe was found to be more
useful in establishing different flow patterns. Changes
in pressure, tube length, and inlet temperature significantly affected the flow regime boundaries. Bergles
et al. [II] conducted a similar study with low-pressure
water, and developed composite flow pattern maps toillustrate the effects of pressure, length, and inlet temperature on the flow regime boundaries. Focusing on
the spray annular regime, Bergles and Roos [15] measured the fi1m thickness, and obtained the first evidenceof smooth dryout at low velocities. The film produced
a fluctuating signal in the electrical probe, pointing to apossibility of nucleation, or entrained vapor, in the film
close to the dryout conditions.
Professor Bergles realized the importance of twophase flow in rod bundles as used in nuclear steam
generator applications. Bergles [26] investigated twophase flow structure visualization with high-pressure
water in a rod bundle, and found significant differencesin flow patterns in different subchannels. Using an electrical resistance probe, he measured the film thickness
in the subchannels, and reported extensive data on flow
regimes as a function of quality and mass velocity. Significant differences were also reported between diabaticand adiabatic conditions. The flow regime boundaries
were shifted to lower quality with heat addition. The
electrical probe was thus seen as a useful tool in sensing an imminent CHF condition.
Another aspect investigated by Professor Bergles was
two-phase critical flow under diabatic conditions, whichis relevant in studying accident conditions in nuclear reactor safety analysis. Bergles and Kelly [27] conducted
experiments with water, and found that for qualities below 0.04, the earlier models developed for diabatic flow
underpredicted flow rate.
heat transfer engineering

Two-Phase Flow Mechanism, and Instabilities
Evans et al. [20, 32] studied the propagation of shockwaves in different two-phase flow regimes with airwater flows. The presence of entrained liquid mist was
confirmed to have an enormous effect on the pressure
wave propagation, and little or no acoustic energy wastransmitted through the liquid film. The flow regimes,
such as slug flow and annular flow, influenced thepressure wave propagation considerably. This fact explained some of the discrepancies in the data reported
earlier in the literature. Yadigaroglu and Bergles [31]conducted experiments with Freon-I 13 to study thedensity wave oscillations, and observed higher mode
oscillations, transmitting at a fraction of the transit timethrough the channel. They also presented a stability map
to explain the phenomenon.

Instrumentation in Two-Phase Flow
Professor Bergles refined the art of experimentationby using many new instrumentation techniques. In oneof his articles, Bergles [21] presented an excellent survey of electrical probes in the study of two-phase flows.
He described the core-wall conductivity probe used indetermining the flow pattern, void fraction, and liquidfilm thickness. This study provides a very useful source
to anyone who wants to develop these probes. Also, hecompared the accuracy of measurements of the electrical probes with other techniques.
More recently, Bonetto et al. [253] used a hot-wireanemometer, and developed a probability density function to obtain the information regarding void fraction,
bubble size, and vapor velocity from flow boiling experiments. Carvalho and Bergles [254] further applied
the hot-wire anemometer to measure the local void fractions in pool boiling ofFC-77 over small vertical heaters,
simulating immersion cooling of electronic chips. The
low contact angle of FC-77 yields a more satisfactory
discrimination between the two phases. Carvalho andBergles [254] also found the optimal sensor temperature corresponding to 60°C, which was much higher
than those reported in earlier studies.

Pool Boiling Heat Transfer
Pool boiling heat transfer data is generally obtained
under steady-state conditions. Thompson and Bergles[28] investigated the applicability of the pool boilingcurve to quenching problems. They found large differences between the quenching data and the predictions from pool boiling correlations. The presence of
surface deposits on the material being cooled disturbed

vol.19 no.3 199825

the vapor film and caused early transinon to nucleate boiling, thereby reducing quench times below theconventional boiling predictions. Further, it also implied that the transient techniques are not suitable forobtaining the steady-state pool boiling curve.
Another major factor affecting pool boiling data inindustrial applications is the presence of contaminants.
Jensen et al. [97] studied experimentally the effect of
Cosmoline, JP-4, turbine oil, and phosphate on the poolboiling curve. The presence of Cosmoline improved
heat transfer rates, the highest coefficient being obtainedat the highest concentration tested (1,000 ppm). However, DNB occurred at lower heat fluxes compared with
distilled water. JP-4, on the other hand, had no influenceon heat transfer or DNB. Turbine oil produced erratic
results, sometimes causing explosive bubble formationon the heater surface. At high concentrations, the heattransfer results were dramatically below the distilledwater curve. DNB was also decreased with the addition of turbine oil. Addition of phosphates generally
shifted the contaminant pool boiling curve back to normal, though the DNB occurred at the same level aswith the contaminants. The orientation, vertical or horizontal, did not affect the boiling characteristics with orwithout contaminants.
Carvalho and Bergles [283] studied pool boiling oversmall vertical heaters, similar to electronic chips, andidentified different regimes, rogue sites, incipient boiling, patchy nucleate boiling, fully developed nucleateboiling, and vapor coalescence (leading to dry patches).
Using a hot-wire anemometer, they obtained void fraction profi les near the heater surface as a function of heat
flux. They established the formation, and subsequent
propagation of dry patches, as the mechanism leading
to CHF in pool boiling.

Subcooled Flow Boiling Heat Transfer
As one of his first articles, Professor Bergles presented an often-referenced article on forced-convection
boiling heat transfer with Professor Rohsenow (Bergles
and Rohsenow [4]). They analyzed flow boiling heattransfer with subcooled and saturated liquids, andpresented a criterion to determine the size ranges ofnucleating cavities for given superheat and flow conditions. Also, the heat transfer rates in the region between forced convection and fully developed boiling
was interpolated using the inception point as the starting point on the line representing forced-convection
heat transfer, and merging with the fully developedboiling curve. This inception condition is still widelyused in the current literature in many different geometries, from smooth tubes to complex ink-jet printerheaters.
26

heattransfer engineering

Bergles and Dormer [18] conducted extensive experiments to study the pressure drop in subcooled boiling of low-pressure water in 2.5. to 4.0-mm-diametertubes. The pressure drop data were then correlated inchart form, and curves were presented to cover the entire range of data. This was one of the first studies in thisarea. The information is useful in studying the stabilityof multichannel systems as well.
Professor Bergles studied the nucleation phenomena
in subcooled boiling systems, and noted that a larger
amount of superheat is needed for a given cavity than ispredicted from theoretical considerations. Murphy andBergles, [43] attributed this effectto the dissolved gasesthat increased the total pressure in a cavity. However, it
was found that, with fluorocarbon systems, large superheats were required to initiate nucleation. This caused
a "hysteresis" effect, which they attributed to the total flooding of the cavities with low-contact-angle fluids, such as fluorinated refrigerants. The commerciallyavailable porous surfaces tend to prevent the deactivation of the cavities.
Vandervort et al. [266] studied the subcooled flow
boiling of water in a 2-mm-diameter lube under highheat-flux boiling. They observed streams of srnall-diameter bubbles (estimated to be 3 /Am) at the exit section of the tube. They presented a detailed descriptionof the forces acting on the bubble and the associatedheat transfer mechanism. They believed that Marangoni
force was the dominant force, followed by surface tension and drag. The discussion presented in the article
provides a good basis for developing a mathematicalmodel describing subcooled boiling heat transfer near
CHF.
Tong et al. [294] investigated pressure drops in smalldiameter tubes with subcooled flow boiling of water.
The earlier work by Bergles and Dormer [18] wasextended with 1.05- to 2.44-mm-diameter stainlesssteel tubes. The subcooled boiling pressure drop was
found to be directly proportional to mass flux and lengthto-tube diameter ratio, but inversely proportional to tube
diameter. Tong et al. [294] developed a pressure drop
correlation that is particularly useful in designing cooling systems to accommodate high heat fluxes.

Flow Boiling Heat Transfer in Enhanced Tubes
Flow boiling heat transfer in enhanced tubes is covered earlier, in the section on enhanced heat transfer.

CHF in Pool and Flow Boiling
CHF studies are important in designing flow boilingsystems for cooling high-flux systems, such as electromagnets. These devices use narrow-diameter passages

vol. 19 no. 3 1998

because of space restrictions. Much of the CHF datain the literature pertained to large-diameter tubes. To
close this gap, Bergles [5] undertook a detailed experimental plan to generate data on CHF for flow of waterin 1.5- to 4-mm-diameter, electrically heated, stainlesssteel tubes. Small-diameter tubes were found to givea higher CHF than large-diameter tubes, making themespecially suitable for high-flux cooling systems. Flowoscillations due to an upstream compressible volume
were found to reduce the burnout heat flux considerably.
Earlier studies, which recorded a lower CHF, were believed to be affected by this problem. Bergles et al. [11]and Bergles and Kelly [27] conducted additional experiments with subcooled water at low pressure. Chokedflow was found to be prevalent under these conditions.
CHF was found to be a complex function of both local
and inlet conditions.
High-pressure water is used in power generation systems, and CHF data are needed in designing these systems. A spray-annular flow pattern occurs at higher
qualities, and is of interest in most two-phase systems.
Bergles and Roos [15] conducted experiments in a recirculating high-pressure steam loop, which reduced theexpenditure considerably. Film thickness was measured
with an electrical probe, and was found to decrease
gradually to zero as the CHF was approached. Measurements in rod bundles indicated wide variations infilm thickness over tubes.
Professor Bergles used many visualization techniques to obtain a good physical picture of complex phenomena. Fiori and Bergles [25] developed a series offilms to study burnout in subcooled flow boiling.
Utilizing experimental data and photographic information about the CHF phenomenon, Fiori and Bergles[33] proposed a model in which stable dry spots areformed underneath bubbles, and these spots can nolonger be quenched at higher heat fluxes, leading tovapor patches covering the heater surface. They presented a comprehensive discussion of possible mechanisms leading to CHF based on the information from a
Fastax (1,200 frames/s) camera and microflash photos.
Bergles [60,72] surveyed the available literature andprovided comprehensive coverage of the description of
the burnout phenomenon in pool boiling with different heater configurations, and different CHF augmentation techniques. This article presents a useful summary,and more important, future directions for researchers.
Similar reports were presented by Bergles [73] for lowquality forced-convection systems, and by Bergles [100]for high-qualti y forced-convection systems. These comprehensive surveys provide a clear picture of the parametric trends and effects of important system variables
on CHF. For pool boiling systems, Park and Bergles[195] collected 2,237 data points for CHF and fitted
heat transfer engineering

polynomial curves to provide engineering equations for
system designers.
In a shell-and-tube evaporator, the tube length covered by baffles may be considered to be under poolboiling conditions. Since the liquid supply is restricted,
the burnout condition could be initiated at this location.
Jensen et al. [70] studied dryout in pool boiling underrestricted annular geometries and found that the dryout
condition occurred at lower clearances and larger widthsof baffle coverage. However, the pool boiling curve
shifted to the left, indicating more efficient heat transfer under the restriction. Jensen et al. [70] attributed thisincrease to thin-film evaporation in the clearance space.
CHF remains a major concern in high-heat-f1ux systems. Vandervort et al. [241] conducted an experimental study in forced-convection systems with water instainless steel tubes having diameters ranging from 0.3
to 2.7 mm. Mass fluxes ranged from 5,000 to 40,000
kg/rn? s, and subcoolings ranged from 40 to 135°C.
In some preliminary tests, a maximum heat flux ofaround 108 W/m 2 was achieved. The CHF was shownto increase with both velocity and subcooling. Smalldiameter tubes provided higher CHF. More detai led data
are presented by Vandervort et al. [280].
In cooling of electronic chips with pool boiling liquid, the heater thickness affects the CHF. Carvalho andBergles [259] studied this effect, and found that none of
the conventional parameters such as wall capacitance,
thermal conductivity, or thermal diffusivity was able
to correlate the CHF data well. Carvalho and Bergles[259] verified a new parameter, "conpacitance,' which
consists of the heater thickness and heater material thermal properties. Although a considerable data spread isstiII observed, this work represents a major step in formulating CHF for thin heater geometries. Using thesame parameters, Golobic and Bergles [260] proposed a
new correlation which correlated their own experimental data for strips cooled on both sides with an averageabsolute deviation of less than 10%.
The mechanism of saturated pool boiling CHF was
discussed by Bergles [257]. The two competing theories, hydrodynamic stability theory and microlayer dryout interpretation, were discussed. Knowledge of theflow pattern near the CHF was deemed necessary to
clarify the situation for flat heaters, which forms thebasis for other geometries as well.

CHF in Helically Coiled Tubes
Helically coiled tubes are used in industries for
single-phase, evaporating and condensing flows, andmany other applications. At system start-up, the subcooled boiling conditions sometime lead to the CHF
condition, which is not well studied in the literature.

vol. 19 no.3 199827

Jensen and Bergles [107, 126] conducted experiments
to obtain CHF data with R-113 in 0.762-mm-diametertubes. The data was correlated and it was found that anadditional parameter consisting of nondimensionalizedradial acceleration was able to account for CHF in helicully coiled tubes. The CHF in these tubes was lower
than in the straight tubes. Undesirable upstream dryout was found to occur if the coil was operated under
low subcooling or low quality near the inlet, and in thehigh-quality region near the exit.
Jensen and Bergles [131] studied an interesting problem of practical importance in solar energy applications,
A helically coiled tube in this application experiences ahigher heat flux on the outside surface that receives thesolar energy directly. Such a heat flux tilt was found to
reduce the CHF. Jensen and Bergles predicted that theliquid film was disrupted by the heat flux tilt. They correlated the data in terms of an additional parameter representing the maximum to average heat flux ratio. The
problem of nonuniform circumferential heating is ofinterest in nuclear applications as well.

Reviews and Summary of Two-Phase
Flow and Boiling Heat Transfer
Professor Bergles directed his efforts to promoting
a clear understanding of many heat transfer phenomcna through critical literature reviews. He also placeda major emphasis on undergraduate education, as isclearly seen in his publication dealing with laboratory
experiments demonstrating bubble behavior in pool andflow boiling (Bergles and Griffith [12]). The experiments were designed to visualize the bubble behavior
with varying subcooling, and varying velocity as wellin forced-flow boiling.
An overview of current information and its relevanceto specific applications is essential to keep researchers
in tune with the needs of the industrial community. In
one of his early articles, Bergles [96] presented such alink by indicating future needs in two-phase flow research, Multibeam X-rays, rotating heat pipes, OTEC
power plants, and pressurized-water reactors (PWRs)
were the examples he used in identifying research topics requiring further attention.
Bergles [I 12] presents a good description of heattransfer mechanisms associated with reactor thermal
hydraulics. He discussed incipient boiling, nucleate boiling, burnout, postdryout, and quenching. The quenching phenomenon is of interest in reactor coolingunder accident conditions. Additional effects due to thetransient nature of the process make it different thanthat described by the steady-state pool boiling curve.
Continuing in the area of nuclear thermal hydraulics,
Bergles [132] presented a comprehensive picture of28

heattransfer engineering

the heat transfer-related issues related to PWRs, andboiling-water reactors (BWRs). The specific issues related to boiling heat transfer were then dicussed infurther detail. Bergles [144] provided some of theempirical correlations used in the steady-state and transient analysis of nuclear reactors.
Boiling heat transfer is a complex phenomenon, andmany research articles are published every year. It istherefore very difficult for design engineers of twophase heat exchangers to keep track of the latest developments. Bergles [188] presented clear information
on various heat transfer mechanisms in two-phase heatexchangers. He also compared various design correlations, and made specific recommendations. This article should be a useful reference for anyone planningto work in this area, and also for those who want toclarify some of the difficult concepts underlying theoretical models available in the literature. Bergles [269]
provided similar information on boiling heat transfer
pertaining to a single tube in a large pool, and single
vertical tube. This work provided a basis for studying
boiling in other, more complex geometries, such as rod
bundles and multiple vertical channels.

Studies and Reviews of Coolingof Electronic Components
Bravo and Bergles [68] reported the performance ofa small enclosure with one wall heated and the otherwall cooled, and evaporating-condensing liquid/vapor
in the enclosed space. They studied the effect of power
level, heater geometry, and dissolved gases on the heattransfer rates. This geometry is of practical interest inelectronic cooling applications.
Bergles et al. [81] present a "representative" surveyof the state of the art (1977) of heat transfer technology
in electronic packaging. They identified that air coolingwould continue to be used in a wide spectrum of coolingapplications, including portable devices and medium tolarge systems. Direct liquid cooling then appeared to bereaching "maturity," but was not quite ready for industrial applications. Liquid rejection systems, such as heat
pipes, and sophisticated technologies were expected tomigrate from the laboratory to industrial products. They
predicted that computer analysis tools would become
standard in the thermal design of electronic packages.
Looking back, their conclusions drawn in 1977 seem tobe right on target.
Bergles [82] presented an article on the evolution ofcooling technology for electrical equipment and electronic devices. He quoted Mouromtseff in his 1942
article as writing: "Without exaggeration one may statethat ill designing electronic tubes there are more
vol. 19 no.3 1998

mechanical, metallurgical, and heat engineering problems than those of pure electronic in character." This
statement was true when Mouromtseff wrote it in 1942,
was valid when Professor Bergles quoted it in 1977,
and as Professor Bergles often mentions in his articles
and talks, is still valid in spite of great strides made incomputer technology. Professor Bergles, pointed out,
however, contradicting Mouromtseff, that the analytical
tools, and not cut-and-try methods, would become thefavored design tools. In this article, Professor Bergles
skillfully took the reader on a journey of electronic
highways, passing through a densely packed thermal
section.
Advanced cooling techniques are being constantly
introduced in electronic packaging applications. In
keeping pace with these developments, Bergles [162]presented a keynote address in which he described additional developments-such as the thermal conduction
module-taking place in the industrial world.
With the advancements in liquid cooling, Bergles[178] presented a comprehensive survey on liquid cooling of electronic equipment. The article presents many
milestones in the development of liquid-cooled systems, with details of some advanced systems (Thermal
Conduction Module, microscopic channels, and open
bath cooling of multichip modules).
Bergles [200] provided a good summary of high-flux
boiling systems as applied to microelectronic cooling.
He discussed many issues related to pool and flow oiling systems. Nakayama and Bergles [218] presented acomprehensive overview of microelectronic cooling in
relation to advanced chip cooling systems.
Bergles and Bar-Cohen [262, 272] provided a detailed account of direct cooling of microelectronic components. They summarized the historical development,
and presented detailed information on a number of advanced systems using the liquid cooling approach. Thisshould serve as a reference for researchers and industry
engineers for any liquid cooling system development.
To improve the heat flux densities of microelectronic
chips, Ma and Bergles [140, 166] studied boiling jet
impingement cooling. R-113 jets were directed against
simulated chips. Ma and Bergles identified subcooled
jets as the most promising way to cool the chips efficiently. Tien et al. [203] introduced nitrogen gas jets
impinging on a chip surface submerged in a pool ofliquid of low volatility (kerosene), with substantial enhancement in heat transfer rates. Ma and Bergles [219]further conducted experiments with R-113 systems anddeveloped a theoretical model to predict the heat transfer in this two-phase, two-component system.
Continuing further with the application of boiling tocooling of chips, Park and Bergles [163,201] studied
the effects of size on the heat transfer coefficient andheattransfer engineering

CHF using simulated chips. They also studied the effect of the mounting-flush or protruding-on the heattransfer performance of the chips. The results were presented in a graph, and they also developed a correlation for predicting the CHF for different configurations.
An interesting fact observed by them was the deactivation of cavities with decreasing heat flux, a phenomenon
they called "reverse overshoot."
Another way of improving performance is to use enhanced pool boiling surfaces on microelectronic chips
in pool boiling with FC-88. Park and Bergles [168] studied the performance of simulated chips with four typesof enhancements: microholes, microfins, Linde High
Flux, and Thermoexcel-E. The temperature overshootand the thermal performance with increasing and decreasing heat fluxes were compared for these surfaces.
The High Flux surface provided the best performanceoverall.
Porous surfaces are used for enhancing pool boilingheat transfer. These surfaces are prepared from a sintering process. The sintering particle material, size, andthe processing govern the structure of the sintered surface. Kim and Bergles [174] conducted an experimental
study to investigate the effect of various parameters on
pool boiling performance in microelectronic applications using R-II3. Three sizes of copper particles wereused. In the fourth sample, the authors employed threelayers with different particle sizes. The performance ofall surfaces was above the plain surface, but the overshoot still posed a problem.
Park and Bergles [177] employed heat sinks to enhance the heat transfer from chips immersed in liquids.
Fins with holes and slots were used with R-113. Park
and Bergles did not observe the typical temperature
overshoot with these devices. The temperature overshoot problems were reduced by Bergles and Kim [202]by introducing an additional heater below the chip surface to provide the initial nucleation sites. Continuingwith this work, Bergles et al. [234] developed porous
surfaces by etching in-situ copper-niobium alloy. The
copper matrix was preferentially etched away, and thesurface was cold-rolled to provide reentrant cavities.
The temperature overshoot was considerably reducedwith these surfaces.
Park et al. [220] studied the performance of simulated
microelectronic chips with different fluorinert liquids.
They also experimentally measured performance withdifferent enhancement devices. This work is expected
to lead into the development of optimized surfaces fordifferent fluorinert liquids.
Carvalho and Bergles [245] conducted an experimental study to determine the effect of subcooling on nucleate boiling and CHF of simulated microelectronic chips.
They tested several enhanced surfaces. They foundvol. 19 no.3 199829

subcooling to be ineffective in improving performanceat high heat fluxes. The CHF, however, increased with
subcooling. Further research in this area is warranted toclari fy some of the issues raised in this article.
The more commonly employed natural-convection
heat transfer in cooling of electronic chips was studied
by Park and Bergles [150, 176]. They used R-113 andwater as the test fluids on simulated chips. The effect ofwidth for small heaters was documented. The heat transfer coefficient increased with decreasing width, with theeffect being greater in R-113 than in water. This effect
was incorporated in a correlation, the first of its kind,to predict the natural-convection heat transfer coefficient for small heated surfaces. Park and Bergles also
investigated the effect of arrangement-in-line or staggered, and spacing between the heaters-for arrays ofchips mounted on a vertical surface. They also noted that
protruding heaters performed about 14% better than thecorresponding flush heaters.
Cooling of multiple chips by natural convection poses
additional problems due to interaction through the fluid
stream flowing over them. Milanez and Bergles [167]studied the effect of a lower heater on the heat transfer from a upper heater. The lower heater enhances theflow of the fluid, but the fluid is also preheated. They
measured the performance of two line heat sources simulating the electronic chips, and compared them against
analytical solutions. This study addresses the practicalproblem encountered in designing electronic systems
consisting of multiple heat sources, each with different thermal requirement and characteristics. Zitz andBergles [274] extended this work to the immersion cooling of multichip modules (MCMs). They developed adetailed computerized test system to monitor the vast
amount of data generated by the MCM module in theentire range covering natural-convection cooling, poolboiling, and CHF. The development of such an advanced
test facility is a result of a multiple series of works initiated by Professor Bergles and other team members on
different aspects of immersion cooling.

History of Heat Transfer
Advancement of technology in various fields is a result of available tools and the technological needs of thesociety at a given time. Scientists and inventors focus
their energies on obtaining solutions to make a difference in the lives of people. The inventions of steam,gasoline, and diesel engines transformed the transportation scenario worldwide. Replacements were made instages, to meet the perceived demands of the marketplace, without stepping ahead too much of the times,
achieving a balance among market forces. Such devel-30

healtransfer engineering

oprnents have taken place in many different fields. The
current computer revolution deserves an entire chapter
in the technological history books.
Knowing the historical development in heat transfer
technology is important to all of us, the heat transfer engineers. It gives us a sense of reference, and relevance,
while deciding our future research directions. Professor
Bergles over the years acted like a historian in searchof original publications and major events related to heattransfer. He read articles published in the 1700s, 1800s,
and early 1900s carefully, and presented concise summaries, removing some misconceptions that had crept
into the literature regarding the origins of many concepts and terms used currently in heat transfer practice.
In his keynote address in 1976, Bergles [77] presented some historical developments, dating from 1756,
drawing from many sources, including authors suchas L. S. De Camp, K. 1. Bell, A. F. Burstall, and E. S.
Ferguson. With clear sketches and interesting photographs, he described the first steam engine (Heron's
whirling aeolipile), Watt's single-acting steam engine,
and Trevithick's locomotive.
The evolution in cooling technology for electrical,
electronic, and microelectronic equipment deserves a
special place in the history of heat transfer. Bergles[179] presented an excellent historical review, startingfrom Mouromtseff's work (1935, 1942) on water andforced-air cooling of vacuum tubes. He summarized
London's (1954) analysis of a 25-kW tube, Kraus's(1965) work on liquid cooling ofa high-power travelingwave tube, and other novel methods introduced by Kaye,
Chu, Hwang, Simons, Kilham and Ursch, Seely, Choi,
Bar-Cohen, and Steinberg.
The enhancement of convective heat transfer has ahistory of its own, dating from the original article by
Newton (Principia, 1687), who introduced the idea ofcooling laws, later put into mathematical form and attributed as Newton's law of cooling. Professor Bergles
took us through this historical journey with landmarks
from Fourier (1822), Joule (1861), Mollier (1897), andthe founder of "modern" heat transfer, Nusselt (1915).
The "roots" of enhanced heat transfer were discoveredby Professor Bergles in early work by Whitham (1896)
on the introduction of retarders (now called twistedtape inserts) in fire-tube boilers; by Lea (192 I), who
introduced spiral fins in the tubes to agitate oil in awater-cooled oil cooler; and by the Swedish inventor
Forssblad (1928), who described novel configurations
for plate-fin heat exchangers. Professor Bergles referred
to a book by Royds (1921), which gives a good pictureof heat transfer technology at that time. The work ofJakob and Fritz (1931) on enhanced boiling surfaces,
and of Tucker and Paris (1921), and Richards on the effect of sound waves on heat transfer, were also visited.
vol. 19 no. 3 1998

The articles written by Professor Bergles on the history of heat transfer have a special place in the heattransfer literature. They serve as time capsules, preserving the major developments through time, and proving
background and history to give all heat transfer practitioners a sense of belonging to this long tradition ofengineering practice.

CLOSUREEngineering research has many facets, including fundamental mechanisms, methods for improvement, experimental data, and models and correlations. Professor
Bergles has exhibited mastery in all these areas, combining science and the art of research. When one looks
at the breadth and depth of the work done by him, it
makes his achievements even more glorious. During
his continuing academic career spanning over 30 years,
he undertook a number of responsibilities, most of themsimultaneously, including conducting research, writing
research articles reports, and proposals, guiding M.S.
and Ph.D. students, attending conferences, preparing
for invited talks and short courses, teaching undergraduate and graduate courses, welcoming visitors, and spearheading the department or the college in administrative
responsibilities. Truly, he serves as a role model for all
engineers, particularly those engaged in the fields ofresearch and education. His research articles and continued interaction with the heat transfer community willundoubtedly inspire many of us to continue this great
tradition of fundamental as well as applied heat transfer
research.

Satish G. Kandlikar
Editor, Heat in History

REFERENCES[11 Berglcs. A. E., and Kaye, J.. Solutions to the Heat-Conduction
Equation with Time-Dependent Boundary Conditions. 1.
Aerospace sci., vol. 28, pp. 251-252,1961.
[2] Berglcs. A. E., and Rohsenow, W M, The Influence ofTemperature Difference on the Turbulent Forced-Convection
Heating of Water. J. Heal Transfer, vol. 84, pp. 268-270,
1962.
[3] Bergles, A. E., The NML 400-Kilogauss 2-Second Pulse System, presented at the Conference on High Magnetic Fields,
Their Production and Their Application, University of Oxford, 1963.
[4] Bergles, A. E., and Rohsenow, W M., The Determination ofForced-Convection Surface-Boiling Heat Transfer, presented
at 6th Natl. Heat Transfer Conf., Boston, 1962; ASME Paper
63-HT-22, 1963; J. Heal Transfer, vol. 86, pp. 365-372, 1964.
[5] Bergles, A. E., Subcooled Burnout in Tubes of Small Diameter, AS ME Paper 63-WA-182. presented at ASME WinterAnnual Meeting, Philadelphia. 1963.

heat transfer engineering[6] Bergles, A. E., The Influence of Flow Vibrations on ForcedConvection Heat Transfer, 1. Heal Transfer, vol. 86, pp. 559560,1964.
[7] Daleas, R. S., and Bergles, A. E.. Effects of Upstream Compressibility on Subcooled Critical Heat Flux, ASME Paper
6S-HT-67, presented at 8th Natl. Heat Transfer Conf., Los
Angeles, 1965.
[8] Bergles. A. E., and Newell, P. H., Jr., The Influence of Ultrasonic Vibrations on Heat Transferto Water Flowing in Annuli.
1111. J. Heal Mass Transfer, vol. 8, pp. 1273-1280. 1965.
[9] Bergles, A. E., and Suo, M., Investigation of Boiling Water
Flow Regimes at High Pressure, presented at Heat Transfer
and Fluid Mechanics lnst., University of Santa Clara. Santa
Clara. CA, Proc. 1966 Heal Transfer and Fluid Mechanics
Institute, pp. 79-99, Stanford University Press, Stanford. CA,
1966.
[10] Bergles, A. E., and Scarola. L. S., Effect ofa Volatile Additiveon the Critical Heat Flux for Surface Boiling of Water in
Tubes, Chem. Eng. Sci., vol. 21. pp. 721-723,1966.
[II] Bcrgles. A. E., Lopina, R. E. and Fiori, M. P., Critical-HeatFlux and Flow-Pattern Observations for Low-Pressure Water
Flowing in Tubes. ASME Paper 66-WA/HT-30, presented at
Winter Annual Meeting, New York, 1966; J. Hear Transfer,vol. 89, pp. 69-74, 1967.
[12] Bergles, A. E., and Griffith, P., Projection Slides for Classroom Demonstration of Heat Transfer with Boiling andCondensation, Bull. Mech. Eng. Educ. vol. 6, pp. 79-83,
1967.
[13] Bcrgles, A. E.. Goldberg, P., and Maulbetsch, J. S., Acoustic Oscillations in a High Pressure Single Channel Boiling
System, presented at Symp. on Two-Phase Flow Dynamics.
Eindhoven, The Netherlands, Proc. the Svmp. all Two-Phase
Flow Dynamics, vol. I, pp. 525-550, The Commission of theEuropean Communities, Brussels, 1967.
[14] Brown. W. T., Jr.. and Bergles, A. E., Measurement of Thermal Conductivity for Electrically Heated Heat Transfer Test
Sections, Proc. Fourth Symp. all Theromopliysical Properlies, University of Maryland, pp. 184--188. ASME, New York,1968.
[151 Bergles, A. E., and Roos, J. P.. Film Thickness and CriticalHeat Flux Observations for High Pressure Water in Spray
Annular Flow. Proc. 1111. SWill'. Research ill Concurrent Gas
Liquid Flow. University of Waterloo, pp. 527-559, Plenum
Press. New York, 1968.
[16J Lopina, R. E, and Bergles. A. E., Heat Transfer and Pressure Drop in Tape Generated Swirl Flow of Single-Phase
Water, ASME Paper 68-WNHT-3, presented at Winter Annual Meeting. New York, 1968; J. Heal Transfer, vol. 91, pp.
434-442, 1969.
[17] Bcrglcs. A. E., The Influence of Heated-Surface Vibration on
Pool Boiling. 1. Heal Transfer, vol. 91, pp, 152- I54, 1969.
[18] Bergles, A. E., and Dormer. T., Jr., Subcooled Boiling Pressure Drop with Water at Low Pressure, 1111. 1. Heal Mass
Transfer, vol. 12, pp. 459-470, 1969.
[19] Bergles, A. E., Survey and Evaluation of Techniques to Augment Convective Heat and Mass Transfer, Prog. Heal and
Mass Transfer, vol. I, pp. 331-424, 1969.
[20J Evans, R. G., Gouse, S. W, Jr., and Bergles, A. E., Pressure Wave Propagation in Adiabatic Slug-Annular-Mist TwoPhase Gas-Liquid Row, AIChE Preprint 12e, presented at the
66th Natl. Meeting, Portland, OR, 1969.
[21] Bergles, A. E., Electrical Probes for Study of TwoPhase Flows, presented at 11th Natl. Heat Transfer Conf.,

vol. 19 no.3 1998

31

Minneapolis, MN; Proc. Symp. Session all Two-Phase Flowlnstrumenation, pp. 70-81, ASME, New York, 1969.
122) Markowitz, A., and Bergles, A. E., Heat Transfer in Spray
Columns, AIChE Preprint II. presented at 11th Natl. Heat
Transfer Conf., 1969; Chem. Eng. Prog. Svmp. Ser., vol. 66,
no. 102, pp, 63-71,1970.
123} Newell, P. H., Jr., and Bcrgles. A. E., Analysis of Combined
Free and Forced Convection for Fully-Developed Laminar
Fluw in Horizontal Tubes, ASME Paper 69-HT-39, presented
at 11th Natl. Heat Transfer Conf., Minneapolis, MN, 1969;
J. Heat Transfer, vol. 92, pp. 83-93, 1970.
1241 Bergles, A. E.. Lee, R. A.. and Mikic, B. B.. Heat Transfer
in Rough Tubes with Tape-Generated Swirl Flow, 1. Heal
Transfer, vol. 91, pp. 443-445, 1969.
[251 Fiori, M. P., and Bergles, A. E., Photographic Study of
Burnout in Flow Subcooled Boiling, color movie for ASME
Heat Transfer Film Library, ASMElESL Film Catalog Second Supplement Listing F-2, 1969.
126J Bcrglcs, A. E., Tho-Phase Flow Structure Observations forHigh Pressure Water in a Rod Bundle, Presented at Symp.
Session on Rod Bundle Heat Transfer, Winter Annual Meeting, Los Angeles, Two-Phase Flow and Heal Transfer ill Rod
Bundles, pp. 47-55, ASME, New York, 1969,127] Bcrglcs, A. E., and Kelly, J. T., Tho-Phase Critical Flow under Diabatic Conditions, presented at Joint Syrup. on Fluid
Mechanics and Measurements in Tho-Phase Systems, Leeds,
England, 1969; Proc. 11lS1. Mech. Eng.. vol. 184, part 3C, pp.
127-133,1969-70.
128] Thompson, W. G., Jr.. and Bergles, A. E., The Relationship ofQuench Data to Steady-State Pool Boiling Data, 1111. J. Heal
Mass Transfer. vol. 13, pp. 55-68, 1970.
1291 Crowley, J. D.. and Bergles, A. E.. Fluid-to-Fluid Modelingof the Hydrodynamic Stability of Flow in Boiling Channels,
ASME Paper 70-HT-8, presented at Fluids Engineering, Heat
Transfer and Lubrication Conf., Detroit, 1970.
130} Bcrglcs, A. E., Fuller W. D., and Hynek, S. J., Influence of
Swirl Flow on Heat Transfer to Nitrogen in Dispersed Flow
Film Boiling, Preprint J-4. presented at the Cryogenic Engineering Conf., Boulder, CO, June 1970; Adv. Cryogenic Eng.,
vol. 16, pp. 426-434, 1971.
1311 Yadigaroglu, G., and Bcrglcs, A. E., Higher-Mode Density
Wave Oscillations, presented at ANS 1970 Annual Meeting,Los Angeles; Trans. Am. Nuclear Soc., vol. 13, no. I, p. 337,
1970.
1321 Evans, R. G.. Gousc, S. w., Jr., and Bergles, A. E.. Pressure Wave Propagation in Adiabatic Slug-Annular-Mist TwoPhase Gas Liquid Flow, Chem. Eng. Sci., vol. 25, pp. 569-582,
1970.
[33] Fiori, M. P., and Bergles, A. E., Model of Critical Heat Flux inSubcooled Flow Boiling, presented at 4th Int. Heat Transfer
Conf., Paris, September 1970; Heal Transfer 1970, vol. 6,
paper B6.3, Elsevier, Amsterdam, 1970.
[341 Bcrglcs, A. E., (On) An Analysis of Laminar Combined
Forced and Free Convection Heat Transfer in a Horizontal Tube, 111/. J. Heal Mass Transfer, vol. 13, p. 1249,
1970.
1351 Bergles, A. E., and Webb R. L.. Bibliography on Augmentation of Convective Heat and Mass Transfer, presented at
ASME Winter Annual Meeting, New York, 1970; Augmentation ofConvective Heat and Mass Transfer, pp. 1-15, ASME,New York, 1970.
136] Bergles, A. E., Brown, G. S" Jr., and Snider, W. D., Heat
Transfer Performance of Internally Finned Tubes, ASME

32

heattransfer engineering

Paper 71-HT-3I, presented at 12th Natl, Heat Transfer Conf.,
Tulsa, OK, August 1971.
[37] Yadigaroglu, G., and Bergles, A. E., Fundamental and HigherMode Density-Wave Observations in Two-Phase Flow: The
Importance of the Single-Phase Region, ASME Paper 71-HT13, presented at 12th Natl. Heat Transfer Cont'., Tulsa, OK,
August 1971.
[38] BOUfe, J. A., Bergles, A. E., and Tong, L. S., Review of TwoPhase Flow Instability, ASME Paper 71-HT-42, presented at
12th Natl. Heat Transfer Conf.. Tulsa, OK, August 1971.
[39] Markowitz, A., and Bergles, A. E., Operational Limits of a
Submerged Condenser, Paper7-12, presented at Int. Symp. on
Two-Phase Systems, Haifa, Israel, August 1971; Prog. Heal
Mass Transfer, vol. 6, pp. 701-716, 1972.
[40J Bergles, A. E., Fuller, W. D., and Hynek, S. J., Dispersed
Flow Film Boiling of Nitrogen with Swirl Flow, 1111. J. Heal
Mass Transfer, vol, 14, pp. 1343-1354, 1971.
[41] Bergles, A. E., and Simonds, R. R., Combined Forced andFree Convection for Laminar Flow in Horizontal Tubes with
Uniform Heat Flux, 111/. 1. Heal Mass Transfer, vol. 14, pp.
1989-2000, 1971.
[42] Bergles, A. E., Thermal-Hydraulic Instability: Most Recent
Assessments, presented at Seminar on Two-Phase Thermohydraulics, Rome, Italy, 1972, Termoidraulico Del Fluidi Bifase.
Comitato Nazionale Per L'Energia Nucleare, pp. 203-232,
1973.
[43] Murphy, R. w., and Bergles, A. E., Subcooled Flow Boiling of Fluorocarbons-Hysteresis and Dissolved Gas Effects
on Heat Transfer, presented at Heat Transfer and Fluid Mechanics Inst.. San Fernando Valley State College, Northridge,
CA, 1972; Proc. 1972 Heal Transfer and Fluid Mechanics
11lS1., pp. 400-416, Stanford University Press, Stanford, CA,
1972.
[44] Yadigaroglu, G., and Bergles, A. E., Fundamental and HigherMode Density Wave Oscillations in Two-Phase Flow, J. Heal
Transfer, vol. 94, pp. 189-195,1972.
[45] Bergles, A. E., Blurnenkrantz, A. R., and Taborek, J., Performance Evaluation Criteria for Enhanced Heat Transfer Surfaces, AIChE Paper 9, presented at 13th Natl. Heat Transfer
Conf., Denver, CO, August 1972.
[46] Chexal, V. K., and Bergles, A. E., Two-Phase Instabilities
in a Low Pressure Natural Circulation Loop, AIChE Paper
19, presented at 13th Natl. Heat Transfer Conf., Denver, CO,
August 1972; AIChE Symp. Sen, vol. 69, no. 31, pp. 37-45,
1973.
[47] Markowitz, A., Mikic, B. B., and Bergles, A. E., Condensation on a Downward Facing, Horizontal Rippled Surface,
ASME Paper 72-HT-33, presented at 13th Natl. Heat Transfer
Conf., Denver, CO, August 1972; J. Heal Transfer, vol. 94,
pp. 315-320, 1972.
[48] Chexal, V. K., and Bergles, A. E.. Two-Phase Instabilities
in a Low Pressure Natural Circulation Loop, 16-mm color
movie produced at Georgia Inst. of Technol., Atlanta, GA,
1971-1972.
[49] Bergles, A. E.. Chu, R. c., and Seely, J. H., Survey of Heat
Transfer Techniques Applied to Electronic Equipment, IBM
Tech. Rep. TR 00.2348, August 4. 1972; ASME Paper 72WNHT-39, presented at ASME Winter Annual Meeting, New
York, November, 1972.
[50] Bergles, A. E., Techiques to Augment Heat Transfer, in
Handbook of Heal Transfer, W. M. Rohsenow and J. P.
Hartnett (eds.), pp. 10-1 to 10-32, McGraw-Hili, New York,1973.

vol. 19 no, 3 1998

[51] Lopina, R. F, and Bergles, A. E., Subcooled Boiling of Water
in Tape-Generated Swirl Flow, J. Heal Transfer, vol. 95, pp.
281-283, 1973.
[52] Bergles, A. E., Recent Developments in Convective HeatTransfer Augmentation, Appl. Mech. Rev., vol. 26, pp. 675682, 1973.
[53] Megerlin, F E., Murphy, R. w., and Bergles, A. E., Augmentation of Heat Transfer in Tubes by Use of Mesh and BrushInserts. AS ME Paper 73-HT-24. presented at 14th Natl. Heat
Transfer Conf., Atlanta, August 1973; 1. Heal Transfer, vol.
96, pp. 145-151, 1974.
[54] Boure, J. A., Bergles, A. E., and Tong, L. S., Review of TwoPhase Flow Instability, Nuclear Eng. Design, vol. 25, pp. 165192,1973.
[55] Taborek, J., Bell. K. J., Bergles, A. E., Howell J. R..
Knudsen, J. G., Scabel, E. P., and Wen, C. Y, Heat Transfer,Allnaal Reviews ofIndustrial and Engineering Chemistry;
vol. 2, pp. 261-295, American Chemical Society, Washington, DC. 1974.
[56] Bergles, A. E.. Blumenkrantz, A. R., and Taborek, J., Performance Evaluation Criteria for Enhanced Heat Transfer
Surfaces, presented at 5th Int. Heat Transfer Conf., Tokyo,
September 1974; Heat Transfer 1974, vol. ll, pp. 234-238,
Japan Society of Mechanical Engineers, Tokyo, 1974.
[57] Hong, S. W., Morcos, S. M., and Bergles, A. E.. Analytical andExperimental Results for Combined Forced and Free Laminar
Convection in Horizontal Tubes, presented at 5th lnt. Heat
Transfer Conf., Tokyo, September, 1974; Heat Transfer 1974,
vol. III, pp. 154-158. Japan Society of Mechanical Engineers,
Tokyo, 1974.
[58] Shelton, S .. Saha, P., and Bergles, A. E., A Study of Heat
Transfer and Erosion in Internal Ballistic Devices, presented
at 11th JANNAF Combustion Meeting. Pasadena, CA, 1974;
11th JANNAF Combustion Meeting, vol. I, pp. 95-118,
Chemical Propulsion Agency Publication 261. 1974.
[59] Bergles, A. E.. Bunn, R. L., and Junkhan, G. H.. Extended
Performance Evaluation Criteria for Enhanced Heat Transfer Surfaces. Leu. Heat Mass Transfer, vol. I, pp. 113-119,
1974.
[60] Berglcs. A. E.. Burnout in Boiling Heat Transfer. Part I: PoolBoiling Systems, Nuclear Safety, vol. 16, pp. 29-42. 1975.
[61] Morcos. S. M., and Bergles, A. E., Experimental Investigationof Combined Forced and Free Laminar Convection in Horizontal Tubes. J. Heal Transfer, vol. 97. pp. 212-219,1975.
[62] Bergles, A. E., Junkhan, G. H., and Bunn, R. L., Performance
Criteria for Cooling System on Agricultural and Industrial
Machines, preprinted for presentation at the Society of Automotive Engineers Mississippi Valley Section Spring Meeting.
Dubuque, lA, April 1975.
[63] Bergles, A. E., Junkhan, G. H. Hagge, J. K., and Jensen,
M. K.. Advanced Cooling Systems for Agricultural and Industrial Machines. preprinted for presentation at the Societyof Automotive Engineers Mississippi Valley Section Spring
Meeting, Dubuque, lA, April 1975.
[64] Hong, S. W.• and Bcrgles, A. E., Augmentation of Laminar
Flow Heat Transfer in Tubes by Means of Twisted-Tape Inserts, ASME Paper 75-HT-44, presented at 15th Natl. Heat
Transfer Conf.. San Francisco, August 1975; J. Heat Transfer,vol. 98. pp. 251-256.1976.
[65] Hong. S. w., and Bergles, A. E., Laminar Flow Heat Transfer
in the Entrance Region of Semi-Circular Tubes with Uniform
Heat Flux. Int. J. Heat Mass Transfer, vol. 7, pp. 123-124.
1976.

heat transfer engineering[66] Bcrgles, A. E., Survey of Augmentation of 1\vo-Phase Heat
Transfer, preprinted for presentation at ASHRAE 1976 Semiannual Meeting, Dallas, February 1976; ASHRAE Trans.. vol.
82, part I, pp. 891-905, 1976.
[67] Royal, J. H., and Bergles, A. E., Experimental Studyof the Augmentation of Horizontal In-Tube-Condensation,
preprinted for presentation at ASHRAE 1976 Semiannual
Meeting. Dallas. February 1976; ASHRAE Trans., vol. 82.
part I, pp. 919-931,1976.
[68] Bravo, H. Y, and Bergles, A. E.• Limits of Boiling Heat
Transfer in a Liquid-Filled Enclosure, presented at Heat
Transfer and Fluid Mechanics Inst., University of California,
Davis. June 1976; Proc. 1976 Heat Transfer and Fluid Mechanics lnst., pp. 114-127, Stanford University Press, Stanford, CA. 1976.
[69] Hong, S. w., and Bergles, A. E.. Theoretical Solutions for
Combined Forced and Free Convection in Horizontal Tubes
with Temperature-Dependent Viscosity. 1. Heat Transfer, vol.
98, pp. 459-465. 1976.
[70] Jensen, M. K., Cooper, P. E.• and Bergtes, A. E., Boiling
Heat Transfer and Dryout in Restricted Annular Geometries.
AIChE Preprint 14, presented at 16th Natl. Heat Transfer
Conf., St. Louis, August 1976: AlChE Symp, Ser., vol. 73, no.
164, pp. 204-213,1977.
[71] Bergles, A. E., Review of Instabilities in Two-Phase Systems,
lecture at NATO Advanced Study Institute on Two-Phase
Flows and Heat Transfer, Istanbul. August 1976; Two-Phase
Flows and Heal Transfer, vol. I, pp. 383-422, Hemisphere.
Washington, DC. 1977.
[72] Berglcs, A. E.. Burnout in Boiling Heat Transfer, Part I: Pool
Boiling Systems. lecture at NATO Advanced Study Institute on Two-Phase Flows and Heat Transfer, Istanbul. August 1976; Two-Phase Flows and Heal Transfer, vol. ll. pp.
671-692, Hemisphere, Washington, DC, 1977.
[73] Bcrgles, A. E.. Burnout in Boiling Heat Transfer, Part ll: Subcooled and Low Quality Forced-Convection Systems, lectureat NATO Advanced Study Institute on Two-Phase Flows andHeat Transfer. Istanbul, August 1976; Two-Phase Flows andHeat Trunsfer, vol. II, pp. 693-720, Hemisphere, Washington,
DC, 1977.
[74] Bergles, A. E., Survey of Augmentation of Two-Phase Heal
Transfer, lecture at NATO Advanced Study Institute on TwoPhase Flows and Heat Transfer, Istanbul, August 1976; TwoPhase Flow and Heat Transfer. vol. II, pp. 817-841, Hemisphere. Washington, DC. 1977.
[75] Bergles, A. E.• Junkhan, G. H.• Hagge, J. K., and Jensen,
M. K., Advanced Cooling Systems for Agricultural and Industrial Machines. SAE Paper 751183, preprinted for SA E
Off-Highway Vehicle Meeting and Exhibition, Milwaukee,
September 1976.
[76] Bergles, A. E.. Junkhan G. H., and Bunn, R. L.. Performance
Criteria for Cooling Systems on Agricultural and Industrial Machines, SAE Paper 751187, preprinted for SAE OffHighway Meeting and Exhibition, Milwaukee. WI, September 1976; SAE TrailS., vol. 85, pp. 38-48. 1976.
[77] Bergles, A. E, Two-Phase Flow and Heal Transfer. 17561976, Keynote address at Two-Phase Flow and Heat Transfer Symp. Workshop. Fort Lauderdale, FL, October 1976;
Two-Phase Transport and Reactor Safety, vol. I, pp. 3-28,
Hemisphere, Washington, DC. 1978.
[78] Bergles, A. E., Survey of Augmentation of Two-Phase Heat
Transfer, Invited Lecture at Two-Phase Flow and Heat Transfer Symp. Workshop. Fort Lauderdale. FL. October 1976;

vol.19 no.3 1998

33

Two-Phase Transport and Reactor Safety, vol. II, pp. 457477, Hemisphere, Washington, DC, 1978.
1791 Bergles, A. E., Burnout in Boiling Heat Transfer, Pan II:
Subcooled and Low Quality Forced-Convection Systems, Nuclear Safety, vol. 18. pp. 154-167, 1977.
1801 Bcrglcs, A. E.. and Jensen. M. K.. Enhanced Single-Phase
Heat Transfer for OTEC Systems. presented at Annual OTEC
Cont., New Orleans, March 1977; Proc. 4th Annual Conf.
Oil Ocean Thermal Energy Conversion, University of New
Orleans, pp. VI-41to VI-55, 1977.
1811 Bcrglcs, A. E., Chu, R. c., and Seely, J. H., Survey of Heat
Transfer Techniques Applied to Electronic Packages, presented at NEPCON West, Anaheim, CA, March 1977, andNEPCON East, Philadelphia, May 1977; Proc. Technical Program National Electronic Packaging and Production Conf.,
Industrial and Scientific Conference Management. Chicago,pp. 370-385, 1977.
1821 Bcrglcs, A. E.. The Evolution of Cooling Technology forElectrical Equipment and Electronic Devices, Report of Research Workshop on Directions of Heal Transfer in Electronic Equipment, Atlanta, October 1977; University of South
Florida Report, pp. 4-20, 1978.
1831 Hong. S. w., and Bergles, A. E., Analysis of Combined Forced
and Free Laminar Heat Transfer in the Entrance Region of
Horizontal Tubes. invited paper presented at Society of Engineering Science Annual Meeting, Lehigh University. November 1977; Proc. 14th Annual Meeting of the Society of Engineering Science, Lehigh University, pp. 453-469, 1977.
1841 Bergles, A. E., Enhanced Forced Convection Heat Transfer
Inside Ducts, Heal Transfer Data Book, Section 503.10, General Electric Co., Schenectady, NY, January 1978.
185) Royal, J. H.. and Bergles, A. E.. Augmentation of Horizontal
In-Tube Condensation by Means of Twisted-Tape Inserts andInternally Finned Tubes, 1. Heat Transfer, vol. 100, pp. 1724, /978.
1861 Bergles, A. E., and Webb, R. L., Bibliography on Augmentation of Convection Heal and Mass Transfer Part I, Previews
Heat Mass Transfer, vol. 4, no. 2, pp. 61-73, 1978.
1871 Bergles, A. E.. Recent Trends in Experimental Heat Transfer and Fluid Mechanics, invited lecture at 1978 Heat
Transfer and Fluid Mechanics Inst., Pullman, WA, June
1978: Prot: 1978 Heat Transfer and Fluid Mechanics
lust .. pp. 35-38, Stanford University Press, Stanford, CA,
1978.
1881 Bcrglcs, A. E.. Augmentation of Forced-Convection Heat
Transfer, presented at NATO Advanced Study Institute on
Turbulent Forced Convection in Channels and Rod Bundles.
Istanbul, July 1978; Turbulent Forced Convection in Channels
and Bundles, vol. 2, pp. 883-909, Hemisphere, Washington,
DC, 1979.
1891 Bcrglcs, A. E., Enhancement of Heat Transfer, keynote paper
presented at Sixth Int. Heat Transfer Conf., Toronto, August
1978; Heat Transfer 1978, vol. 6, pp. 89-108, Hemisphere,
Washington, DC, 1978.
1901 Marner, W. 1., and Bergles, A. E., Augmentation of Tubeside Laminar Flow Heat Transfer by Means of Twisted-Tape
Inserts, Static-Mixer Inserts and Internally Finned Tubes, presented at Sixth Int. Heat Transfer Conf., Toronto, August
1978; Heat Transfer 1978, vol. 2, pp. 583-588, Hemisphere,
Washington, DC, 1978.
1911 Royal, J. H., and Bergles, A. E.. Pressure Drop and Performance Evaluation of Augmented In-Tube Condensation, presented at Sixth Int. Heat TransferConf. Toronto, August 1978;

34

heat transfer engineering

Heat Transfer 1978, vol. 2, pp. 459-464, Hemisphere, Washington, DC, 1978.
192] Bergles, A. E., and R. L., Webb, Bibliography on Augmentation of Convective Heat and Mass Transfer Pan 2, Previews
Heat Mass Transfer, vol. 4, no. 4, pp. 89-106, 1978.
193] Bergles, A. E., Webb, R. L., and Junkhan, G. H., Energy
Conservation via Heat Transfer Enhancement, presented at
Midwest Energy Conf., Chicago, November 1978; Energy,
vol. 4, pp. 193-200, 1979.
194] Bergles, A. E., and Webb, R. L., Bibliography on Augmentation of Convective Heat and Mass Transfer Pan 3, Previews
Heat Mass Transfer, vol. 5, no. 2, pp. 83-103, 1979.
195] Bergles, A. E., and Webb, R. L., Bibliography on Augmentation of Convective Heat and Mass Transfer Part 4, Previews
Heat Mass Transfer, vol. 5, no. 3, pp. 83-102, 1979.
1961 Bergles, A. E., Future Directions of Researeh in Multi-Phase
Flow and Heat Transfer, opening lecture at Second MultiPhase Flow and Heat Transfer Symp.-Workshop, Miami
Beach, FL, April 1979; Multiphase Transport Fundamentals,
Reactor Safety, Applications, vol. I, pp. 3-18, Hemisphereand McGraw-Hill, Washington, DC, 1980.
1971 Jensen, M. K .. Bergles, A. E., and Jeglic, F. A., Effects ofOily Contaminants on Nucleate Boiling of Water, presented
at 18th Natl. Heat Transfer Conf., San Diego, CA, August
1979;AlChE Symp. Ser. 189, vol. 75, pp. 194-203, 1979.
198J Berglcs, A. E., United States Activity in Two-Phase Flow
Dynamics, presented at Japan-U.S. Seminar on Two Phase
Flow Dynamics, Kobe, Japan, July 1979; Two-Phase Flow
Dynamics. Japan-UiS. Seminar 1979, pp. 43-58, Hemisphereand McGraw-Hill, Washington, DC, 1981.
199] Luu, M., and Bergles, A. E., Experimental Study of the Augmentation of In-Tube Condensation of R-113, preprinted forpresentation at ASHRAE 1979 Semiannual Meeting, Detroit,
MI,June 1979; ASHRAE Trans., vol. 85, pan 2, pp. 132-145,
1979.
[100] Bcrgles, A. E., Burnout in Boiling Heat Transfer. Pan III:High Quality Forced Convection Systems, Nuclear Safely,
vol. 20, pp. 671-689,1979.
110 I J Bergles, A. E., Energy Conservation and Heat Transfer Enhancement, keynote lecture atlnt. Meeting on Industrial Heat
Exchangers and Heat Recovery, Liege, Belgium, November
1979, preprint volume, p. 275.
[102] Bergles, A. E., and Webb, R. L., Bibliography on Augrnentalion of Convective Heat and Mass Transfer, Pan 5, Previews
Heal Mass Transfer, vol. 6, no. I, pp. 89-106, 1980.
[103) Luu, M., and Bergles, A. E., Enhancement of Horizontal In-Tube Condensation of R-113, presented at ASH RAE
Semi-Annual Meeting, Los Angeles, January 1980; ASHRAE
Trans., vol. 86, part I, pp. 293-312, 1980.
[104] Bergles, A. E., and Chyu, M.-C., Verbesserung des Blasensiedens Durch Oberflachcn mit Porosen Metallischen,
Ubcrzugen, presented at Verein Deutscher IngenieureGesellschaft Verfahrenstechnik und Chemieingenieurwesen, Sitzung des Fachausschusses, Warrne-und StoffUbertragung, Darmstadt, West Germany, April 1980.
1105] Bergles, A. E., and Webb. R. L., Bibliography on Augmentation of Convective Heat and Mass Transfer-Pan 6, Previews
Heat Mass Transfer, vol. 6. no. 3, pp. 292-313, 1980.
[106] Joshi, S. D., and Bergles, A. E., Analytical Study ofHeat Transfer to Laminar in-Tube Flow of Non-Newtonian
Fluids, Presented at 191h Natl. Heat Transfer ConI'., Orlando, FL, July 1980; AlC/IE Symp. Ser. No. 199, vol. 76,
pp. 270-281.

vol. 19 no. 3 1998

[107] Jensen, M. K., and Bergles, A. E., Boiling Heat Transfer andCritical Heat Flux in Helical Coils, ASME Paper 80-HT-49,
presented at 19th Natl. Heat TransferConf., Orlando, FL, July
1980.
[108] Joshi, S. D., and Bergles, A. E., Experimental Study of Laminar Heat Transfer to In-Tube Flow of Non-Newtonian Fluids,
J. Heat Transfer, vol. 102, pp. 397--40 I, 1980.
[109] Bergles, A. E., Principles of Heat Transfer Augmentation.
1: Single-Phase Heat Transfer. presented at NATO Advanced
Study Institute on Heat Exchangers.Istanbul, July 1980: Heat
Exchangers, Thermal Hydraulic Fundamentals and Design,
pp. 8 I9-842, Hemisphere and McGraw-Hili, Washington,
DC, 1981.
[110] Bergles. A. E., Principles of Heat Transfer Augmentation.
II: Two-Phase Heat Transfer, Presented at NATO Advanced
Study Institute on Heat Exchangers, Istanbul, July 1980; Heat
Exchangers, Thermal Hydraulic Fundamentals and Design,
pp, 857-881, Hemisphere and McGraw-Hili, Washington,
DC, 1981.
[III J Berglcs, A. E., Applications of Heat Transfer Augmentation,
Presented at NATO Advanced Study Institute on Heat Exchangers. Istanbul. July 1980; Heat Exchangers, Thermal Hydraulic Fundamentals and Design, pp. 883-911, Hemisphereand McGraw-Hili, Washington, DC, 198 I.
r 112] Bergles, A. E., Boiling Heat Transfer Mechanisms in Reactor Thermal-Hydraulics, Presented at ANS/ASMElNRC Int.
Topical Meeting on Nuclear Reactor Thermal-Hydraulics,
Saratoga, NY. October 1980; Proc. ANSIASMEINRC 11lI.
Topical Meeting all Nuclear Reactor Thermal-Hydraulics,
NUREG/CP-OOI4, vol. 2, pp. 1019-1042. 1980.
[I 13] Joshi, S. D., and Bergles, A. E., Survey and Evaluation of
Passive Heat Transfer Augmentation Techniques for Laminar
Flow. J. Thermal Eng.. vol. I. pp. 105-124, 1980.
[114] Luu, M., and Berglcs. A. E., Augmentation of In-Tube Condensation of R- I 13 by Means of Surface Roughness, presented at ASHRAE Semiannual Meeting, Cincinnati, OH,
1981; ASHRAE Truns., vol. 87, part 2, pp. 33-50, 198 I.
[I 15] Berglcs, A. E., Survey of Heat Transfer Characteristics ofDeep Spirally Fluted Tubing Presented at 20th ASME-AIChE
Natl. Heat Transfer Conf., Milwaukee, WI, August 1981; Advallces in Enhanced Heat Transfer-s-Ivs l , HTD-Vol. 18, pp.
21-33, ASME, New York, 1981.
[116] Bcrgles, A. E., and Chenoweth, J. M., On the Presentationof Performance Data for Enhanced Tubes Used in Shelland-Tube Heat Exchangers. W. J. Marner, presented at 20th
ASME-AIChE Natl. Heat Transfer Conf., Milwaukee, WI,
August 1981; Advances in Enhanced Heat Transfer-i-l vs l ,HTD-Vol. 18. pp. 1-10, ASME, New York, 1981.
[117] Bcrgles, A. E., and Chyu, M. C, Characteristics of Nucleate
Pool Boiling from Porous Metallic Coatings, presented at
20th ASME-AIChE Natl. Heat Transfer ConI'. Milwaukee,
WI, August 1981; Advanced in Enhanced Heat Transfer1981, HTD-Vol. 18, pp. 61-71. ASME, New York, 1981.
rI 18] Joshi, S. D., and Bergles, A. E., Analytical Study of Laminar
Flow Heat Transfer 10 Pscudoplastic Fluids in Tubes with
Uniform Wall Temperature, presented at 20th ASME-AIChE
Natl. Heat Transfer Conf., Milwaukee, August, AlChE Symp.
Ser., vol. 77, no. 208, pp. I t4-122, 1981.
[119] Bergles, A. E., Prediction of the Effects of TemperatureDependent Fluid Properties on Laminar Heat Transfer, presented at NATO Advanced Study Institute on Low Reynolds
Number Forced Convection in Channels and Bundles,
Ankara, Turkey. July 198 I; Low Reynolds Number Flow Heat

heattransfer engineering

Exchangers, pp. 45/--471, Hemisphere, Washington, DC, andSpringer-Verlag, Berlin, 1983.
[120] Bergles, A. E., Experimental Verification of Analyses
and Correlation of the Effects of Temperature-Dependent
Fluid Properties on Laminar Heat Transfer. presented at
NATO Advanced Study Institute on Low Reynolds Number Forced Convection in Channels and Bundles, Ankara,
Turkey, July 1981: Low Reynolds Number Flow Heat Exchangers, pp. 473--486, Hemisphere, Washington, DC, andSpringer- Verlag, Berlin, 1983; Heat Exchanger Sourcebook,pp, 231-244, Hemisphere, Washington, DC, and SpringerVerlag, Berlin, 1986.
[121] Berglcs, A. E., Effects of Temperature-Dependent Properties on Non-Newtonian Fluids, presented at NATO Advanced
Study Institute on Low Reynolds Number Forced Convection in Channels and Bundles, Ankara, Turkey. July 1981;
Low Reynolds Number Flow Heat Exchangers, pp. 593-6 I2,Hemisphere Washington, DC, and Springer-Verlag, Berlin,
1983; Heat Exchanger Sourcebook, pp. 245-264, Hemisphere, Washington, DC, and Springer-Verlag, Berlin, 1986.
[122] Bergles, A. E., and Joshi, S. D., Augmentation Techniquesfor Low Reynolds Number In-Tube Flow, presented at
NATO Advanced Study Institute on Low Reynolds Number Forced Convection in Channels and Bundles, Ankara,
Turkey, July 1981: Low Reynolds Number Flow Heat Exchangers, pp. 695-720, Hemisphere, Washington, DC, andSpringer-Verlag, Berlin, 1983: Heat Exchanger Sourcebook,pp. 619-644. Hemisphere, Washington, DC, and SpringerVerlag, Berlin, 1986.
[123] Webb, R. L., and Bergies, A. E., Performance Evaluation
Criteria for Selection of Heat Transfer Surface Geometries
Used in Low Reynolds Number Heal Exchangers, presented
at NATO Advanced Study Institute on Low Reynolds Number
Forced Convection in Channels and Bundles, Ankara, Turkey,
July 198 I; Low Reynolds Number Flow Heat Exchangers.
pp. 735-752, Hemisphere, Washington, DC, and SpringerVerlag, Berlin, 1983.
[124] Bergles, A. E., Two-Phase Flow and Heat Transfer, 17561981, Heat Transfer Eng., vol. 2, no. 3--4, pp. 101-114,1981.
[125J Joshi, S. D., and Bergles, A. E., Heat Transfer 10 Laminar
In-Tube Flow of Pseudoplastic Fluids, AlChE J., vol. 27, pp,872-875, 198 I.
[126J Jensen, M. K., and Bergles, A. E., Critical Heat Flux in Helically Coiled Tubes, J. Heat Transfer, vol. 103, pp. 660-666,
1981.
[127] Bergles, A. E., and M. C, Chyu, Characteristics of Nucleate
Pool Boiling from Porous Metallic Coatings, J. Heal Transfer,vol. 104, pp. 279-285, 1982.
[128] Nakazatorni, M., and Bergles, A. E., Film Evaporation Modcl
on Horizontal Tubes, Res. Rep. Ube Technical College, no.
27, pp. 63-70,1981.
[129J Joshi, S. D., and Bergles, A. E., Heat Transfer to Laminar
Flow of Non-Newtonian Pseudo plastic Fluids in Tubes, presented at 7th Int. Heat Transfer Conf., Munich, West Germany, September 1982; Heat Transfer 1982, Proc. SeventhInt. Heat Transfer Conf., vol. 3, pp. 5 I-56, Hemisphere,
Washington, DC, 1982.
[130] Chyu, M. C, Bergles, A. E., and Mayingcr, F., Enhancement of Horizontal Tube Spray Film Spray Evaporator,presented at 7th Int. Heat Transfer Conf., Munich, West
Germany, September 1982; Heat Transfer 1982, Proc. Seventh Int. Heat Transfer Conf., vol. 6, pp. 275-280, Hemisphere, Washington. DC, 1982.

vol. 19 no.3 1998

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113II Jensen, M. K.. and Berglcs, A. E., Critical Heat Flux in Helical Coils with a Circumferential Heat Flux Tilt toward theOutside Surface, 1111. J. Heal Mass Transfer, vol. 25, pp. 13831396, 1982.
11321 Bcrglcs, A. E., Heal Transfer Mechanics in Nuclear Reactor Thermal-Hydraulics, presented at I st Latin American Congress on Heat and Mass Transfer, La Plata, Argentina, October-November 1982; Latin American J. Heal
Mass Transfer, vol. 8, pp. 107-129,1984.
11331 Bergles, A. E., Augmentation of Heat Transfer, Heal Exchanger Design Handbook, Fluid Mechanics and Heal Trans-

fer, vol. 2 section 2.5. I I, pp. 2.5.11-1-12, Hemisphere, Washington, DC, 1983.
1134] Bcrglcs, A. E., Augmentation of Condensation, Heal Exchanger Design Handbook, Fluid Mechanics and Heal Trans-

fer, vol. 2, section 2.6.6, pp. 2.6.6-1-4, Hemisphere, Washington, DC, 1983.
11351 Bcrglcs, A. E., Augmentation of Boiling and Evaporation,
Heal Exchanger Design Handbook, Fluid Mechanics and
Heal Transfer, vol. 2, section 2.7,9, pp. 2.7.9-1-5, Hemisphere, Washington, DC, 1983.

11361 Marner, W. J., Berglcs, A. E., and Chenoweth, J. M.. On the
Presentation of Performance Data for Enhanced Tubes Usedin Shell-and- Tube Heat Exchangers, J. Heal Transfer, vol.
105, pp. 358-365, 1983.
11371 Webb, R. L., and Bcrgles, A. E.. Heat Transfer Enhancement:
Second Generation Technology, Mech. Eng.. vol. I 15, 00. 6,
pp. 60-67, 1983.
1138J Junkhan, G. H., Bcrglcs, A. E.. Nirrnalan, V.. andRavigururajan, T. S.. Investigation of Turbulators for Fire
Tube Boilers, ASME Paper 83-HT-44, presented at2 1st Natl.
Heat Transfer Conf., Seattle, WA, July 1983.
11391 Berglcs, A. E., Augmentation of In-Tube Condensation,
ASHRAE Research Note 39,ASHRAEJ., August 1983, p. 46.
114111 Ma, C. F., and Bergles, A. E., Boiling Jet Impingement Cooling of Simulated Microelectronic Chips, presented at ASME
Winter Annual Meeting Boston, November 1983; Heal TransJer ill Electronic Equipment, HTD-Vol. 28. pp. 5-12, ASME,New York, 1983.
1141] Bergles, A. E., and Webb, R. L., Heat Transfer Enhancement: Second Generation Technology, Presented at 1984 I ndustrial Energy Technology Conf and Exhibition, Houston,
TX, April 1984; Proc. Sixth Annual Industrial Energy COIlservation Technology Conf. and Exhibition, vol. I, pp. 25226ll. Texas Economic Development Commission, Houston,
1984.
11421 Bergles, A. E., Enhancement of Boiling and Condensing, presented at China-U.S. Seminar on Two-Phase Flow and Heat
Transfer, Xian, People's Republic of China, May 1984; TwoPhase Flow and Heal Transfer: Chilla-U.S. Progress, pp.
283-307, Hemisphere, Washington, DC. 1985.
11431 Bergles, A. E.. Burnout in Boiling Heat Transfer: High
Quality Forced-Convection Systems, presented at China-U.S.
Seminar on Two-Phase Flow and Heat Transfer, Xian, People's Republic of China, May 1984; Two-Phase Flow and
Heal Transfer: China-U'S. Progress, pp. 177-206, Hemisphere, Washington, DC, 1985.
11441 Bcrglcs, A. E., Progress in Understanding Heat Transfer in
Nuclear Reactor Cooling Systems, Seminario Sobre Transfcrcncia de Calor y Materia en Teehnologia Nuclear, Comite
Argentino de Transfercncia de Calor y Materia, Buenos
Aires, Argentina. July 27, 1984; Cuadernos-Transferencia deCalor y Materia ell Technologia Nuclear, pp. 39-62, Comite

36

heat transfer engineering

Argentino de Transferencia de Calor y Materia, Buenos aires,
Argentina, 1984.
[145] Bergles, A. E., Nirmalan, Y, and Ravigururajan, T. S., Investigation of Turbulators for Fire Tube Boilers, G. H., Junkhan,
J. Heal Transfer, vol. 107, pp. 354--360, 1985.
[146] Chyu, M.-C., and Bergles, A. E., Falling Film Evaporation
on a Horizontal Tube. presented at 23rd Natl. Heat Transfer
Conf Denver, CO, August 1985; Multiphase Flow and Heal
Transfer, HTD-Vol. 47, pp. 39-48, ASME, New York, 1985.
[147] Marner, W. J., and Bergles, A. E.. Augmentation of Highly
Viscous Laminar Tubeside Heat Transfer by Means of a
Twisted-Tape Insert and an Internally Finned Tube, presented
at 23rd Natl. Heat Transfer Conf., Denver,CO, August 1985;
Advances ill Enhanced Hear TrallsJer-1985. HTD-Vol. 43,
pp. 19-28, ASME, New York. 1985.
1148] Chyu, M. c., and Bergles, A. E., Enhancement of Horizontal
Tube Spray Film Evaporators by Structured Surfaces, presented at 23rd Natl. Heat Transfer Conf., Denver, CO, August
1985; Advances ill Enhanced Heal Transfer-i-lvs i, HTDVol. 34, pp. 39-48, ASME New York, 1985.
[149] Bergles, A. E., and Webb, R. L., A Guide to the Literature on
Convective Heat Transfer Augmentation presented at 23rd
Natl. Heat Transfer Conf., Denver, CO, August 1985; Advallces ill Enhanced Heal TrallsJer-1985, HTD-Vol. 43, pp.
81-90, ASME, New York. 1985.
[150J Park, K.-A., and Bergles, A. E., Natural Convection Heat
Transfer Characteristics of Simulated Microelectronic Chips,presented at 23rd Natl. Heat Transfer Conf., Denver, CO.
August 1985; Hear Transfer ill Electronic Equipmelll-1985.
HTD-Vol. 48, pp. 29-38. ASME. New York, 1985.
rI5 II Bcrglcs, A. E., Techniques to Augment Heat Transfer, in
Handbook oj Heal Transfer Applications, pp. 3-1 to 3-80.
W. M. Rohsenow, J. P. Hartnett, and E. N. Ganic (cds.).
McGraw-Hili, New York, 1985.
11521 Ma. c.-F., Gar, Y-P., Tang, F. J., and Bergles, A. E., A
New Method of Heat Transfer Augmentation by Means ofForeign Gas Jet Impingement in Liquid Bath, presented at
Int. Symp. on Heat Transfer, Beijing, People's Republic ofChina, October 1985; Hear Transfer Science and Technology,
pp. 789-797, Hemisphere, Washington, DC, and SpringerVerlag, Berlin, 1987,
1153J Bcrgles, A. E., Augmented Heat Exchangers for High Ternperature Applications, presented at Int. Centre for Heatand Mass Transfer XVII Int. Symp. on High Temperalure Heat Exchangers, Dubrovnik, Yugoslavia, Hemisphere,
Washington. DC, August 1985; also in High-Temperature
Heal Exchangers, pp. 39-59.154, Springer-Verlag, Berlin.
1986.
l154] Bergles, A. E., Heat Transfer Enhancement-Application to
High Temperature Heat Exchangers, presented at 1985 U.S.Japan Heat Transfer Joint Seminar on Heat Transfer in HighTechnology and Power Engineering, San Diego, CA. Hemisphere. Washington, DC. September 1985; also in Heal Trans[er ill High Technology and Power Engineering, SpringerVerlag, Berlin, 1987.
[155] Ravigururajan, T. S" and Bergles, A. E., General Correlations
for Pressure Drop and Heat Transfer for Single-Phase Turbulent flow in internally Ribbed Tubes, presented at ASME
Winter Annual Meeting, Miami Beach, FL, November 1985;
Augmentation ojHeal Transfer ill Energy Systems, HTD-Vol.
52, pp. 9-20. ASME, New York, 1985.
[156] Ayub, Z. H., and Bergles, A, E., Pool Boiling from GEWA
Surfaces in Water and R- I 13, presented at ASME Wintervol. 19 no. 3 1998

Annual Meeting, Miami Beach, FL, November 1985; Augmentation of Heat Transfer ill Energy Systems, HTD- Vol. 52,
pp. 57-66, ASME, New York, 1985.
[157] Bhavnani, S. H.. and Bergles, A. E., Interferometric Studyof Laminar Natural Convection from an Isothermal Vertical
Plate with Transverse Roughness Elements, presented at 8th
Natl. Heat and Mass Transfer Conf., Visakhapatnam, India,
December 1986; Current Research ill Heat and Mass Transfer, pp. 1-12, Hemisphere Washington, DC, and SpringerVerlag, Berlin, 1986.
[158] Baustian, J. 1.. Pate, M. B., and Bergles, A. E.. Properties
of Oil-Refrigerant Liquid Mixtures with Applications to Oil
Concentration Measurement: Part 1-Thermophysical andTransport Properties presented at ASHRAE Winter Meeting,
San Francisco, January ASHRAE Trans., vol. 92, part I A, pp.
55-73.1986.
[159J Baustian. J. 1.. Pate, M. B., and Bergles, A. E., Properties
of Oil-Refrigerant Liquid Mixtures with Applications to Oil
Concentration Measurement: Part II-Electrical and Optical Properties, presented at ASH RAE Winter Meeting, San
Francisco, January 1986; ASHRAE Trails. vol. 92. part I A,
pp. 74-92, 1986.
[160J Nelson, R. M., and Bergles, A.E., Performance Evaluation for
Tubeside Heat Transfer Enhancement of a flooded Evaporator
Water Chiller, presented at ASHRAE Winter Meeting, San
Francisco. January 1986; ASHRAE Trans., vol. 92, part IB,
pp. 739-755, 1986.
[161 J Nirmalan, V., Junkhan. G. H., and Berglcs, A. E., Investigation of the Effect of Turbulence-Producing Inserts on Heat
Transfer in Tubes with Application to Fire-Tube Boilers, presented at ASH RAE Winter Meeting, San Francisco, January
1986: ASHRAE Trans., vol. 92, part I B, pp. 791-809, 1986.
(162J Bergles, A. E.. The Evolution of Cooling Technology
for Electrical. Electronic, and Micro-electronic Equipment,
keynote address for Sessions on Heat Transfer in Electronic Equipment, AIAA/ASME 4th Thermophysics andHeat Transfer Conf. Boston, June 1986; Heat Transfer ill
Electronic Equipment 1986, HTD-Vol. 57, pp. 1-9, ASME,New York, 1985; Proc. ASMtlJSME Thermal Engineering
Joint Conf., vol. I, pp. 453--461. ASME, New York, 1991.
[163] Park, K. A., and Bergles, A. E., Effects of Size of Simulated
MicroelcctronicChips on Boiling and Critical Heat Flux. presented at AIAAIASME 4th Thermophysics and Heat Transfer
Conf.. Boston, June 1986: Heal Transfer ill Electronic Equipment 1986, HTD-Vol. 57, pp. 95-102, ASME. New York,
1986.
Junkhan, G. H., and Bergles, A. E., Mechanisms[164J Nirmalan,of Enhancement with Turbulators for Fire-Tube Boilers, presented at ASHRAE 1986 Annual Meeting, Portland, OR, June
1986; ASHRAE Trans., vol. 92, part 2B. pp. 496-505,1986.
[165J Khanpara, J. C, Bergles, A. E., and Pate, M. P., Augmentation of R-113 In-Tube Evaporation with Micro-Fin Tubes,
presented at ASHRAE 1986 Annual Meeting Portland, OR,
June 1986; ASHRAE Trans., vol. 92, part 2B, pp. 506-524,
1986.
[1661 Ma, C. F., and Bergles, A. E., Jet Impingement Nucleate Boiling, lilt. J. Heal Mass Transfer, vol. 29, pp. 1095-1101, 1986.
[167J L. F., Milanez, and Bergles, A. E., Studies on Natural Convection Heat Transfer from Thermal Sources on a Vertical
Surface, presented at 8th Int. Heat Transfer Conf. San Francisco, August 1986; Heat Transfer 1986, Proc. 8th Int. Heat
Transfer Conf., vol. 3, pp. 1347-1352, Hemisphere, Washington, DC, 1986.

v.,

heat transfer engineering[168J Park, K. A., and Bergles, A. E., Boiling Heat Transfer Characteristics of Simulated Microelectronic Chips with Detachable Heat Sinks, presented at 8th Int. Heat Transfer conf.,
San Francisco. August 1986; Heal Transfer 1986, Proc. 8thInt. Heat Transfer Conf., vol. 4, pp. 2099-2104, Hemisphere,
Washington, DC, 1986.
[169] Winer, W. a., Bergles, A. E, Cremers, C J., Sabersky, R. H.,
Sirignano, W. A., and Westwater, J. w., Needs in Thermal
Systems, Mech. Ellg., pp.39--46, August 1986.
[170J Baustian, J. J., Pate, M. B., and Bergles, A. E., Properties of Oil-Refrigerant Liquid Mixtures with Applications
to Oil Concentration Measurements, presented at Int. Centre for Heat and Mass Transfer XVIII Int. Symp. on Heatand Mass Transfer in Cryoengineering and Refrigeration,
Dubrovnik, Yugoslavia, September 1987; Heat and Mass
Transfer ill Refrigeration and Cryogenics, pp. 404--428,
Hemisphere, Washington, DC, and Springer-Verlag, Berlin,
1986.
[171) Khanpara, J. C., Bergles, A. E., and Pate, M. B., Augmentation of R-113 In-Tube Condensation with Micro-Fin Tubes,
presented at Winter Annual Meeting, Anaheim, CA. December 1986: Heat Transfer ill Air Conditioning and Refrigeration Equipment, HTD- Vol. 65, pp. 21-32, ASME, New York,1986.
[172J Ravigururajan T. S., and Bergles, A. E., An Experimental
Verification of General Correlations for Single-Phase Turbulent Flow in Ribbed Tubes, presented at ASME WinterAnnual Meeting, Anaheim, CA, December 1986; Advances
ill Heat Exchanger Design, HTD- Vol. 66, pp. I-II, ASME,New York, 1986.
[173) Bergles, A. E.. Update to "Recent Developments in Convective Heat-Transfer Augmentation (AMR 26 1973: 675-682),
Applied Mechanics Update-1986, pp. 241-245, ASME,New York, 1986.
[174] Kim C-l., and Bergles, A. E.. Incipient Boiling Behavior of
Porous Surfaces Used for Cooling of Micro-electronic Chips,presented at 4th Miami Int. Symp. on Multiphase Transport and Particulate Phenomena, Miami Beach, FL, December 1986; Particulate Phenomena and Multiphase Transport,
vol. 2, pp. 3-18, Hemisphere, Washington, DC, and SpringerVerlag, Berlin, 1987.
1175J Schlager, L. M., Pate, M. B., and Bergles, A. E., A Survey of Refrigerant Heat Transfer and Pressure Drop Emphasizing Oil Effects and In-Tube Augmentation, presented
at ASHRAE Winter Meeting, New York. January 1987:
ASHRAE Trans., vol. 93, part I, pp. 392--416, 1987.
[176J Park, K.-A., and Bergles, A. E., Natural Convection Heat
Transfer Characteristics of Simulated Microelectronic Chips,
J. Heat Transfer, vol. 109, pp. 90-96,1987.
[1771 Park, K.-A., and Bergles, A. E.. Heat Transfer Characteristics of Simulated Microelectronic Chips with Heat Sinks,
presented at Int. Symp. on Cooling Technology for Electronic
Equipment. Honolulu, HI, March 1987; Cooling Technology
for Electronic Equipment, pp. 353-367, Hemisphere. Washington, DC, 1988.
[178J Bergles, A. E., Liquid Cooling for Electronic Equipment,
keynote lecture at Int. Symp. on Cooling Technology for Electronic Equipment, Honolulu, HI. March 1987; Cooling Techniques for Computers, pp. 141-171, Hemisphere, New York,1991.
[179J Bergles, A. E., Evolution of Cooling Technology for Electrical, Electronic, and Microelectronic Equipment, Heat Transfer Eng., vol. 7, no. 3--4, pp. 97-106, 1987.

vol. 19 no.3 1998

37

11801 Nirmalan, v., Junkhan, G. H.. and Bergles, A. E., A Basic Surface Renewal-Penetration Model of Heat Transfer in
Tubes, with Turbulators for Fire-Tube Boilers, presented at
ASH RAE Annual Meeting, Nashville, TN, June-July 1987;
ASHRAETralls., vol. 93, part 2, pp. 1985-1999, 1987.
11811 Ayub, Z. H.. and Bergles, A. E., Pool Boiling from GEWA
Surfaces in Water and R-113, warme-und Stoffubertragung,vol. 21, pp. 209-219,1987.
11821 Manglik, R. M., and Bergles, A. E., A Correlation for Laminar
Flow Enhanced Heat Transfer in Uniform Wall Temperature
Circular Tubes with Twisted-Tape Inserts, presented at Natl.
Heat Transfer ConI'., Pittsburgh, PA, August 1987; Advances
ill Enhanced Heat Transfer 1987, HTD-Vol. 68, ASME, New
York, 1987.
11831 Khanpara, J. C., Bcrglcs, A. E., and M. B., Pate, A Comparison of In-TUbe Evaporation of Refrigerant 113 in Electrically Heated and Fluid Heated Smooth and Inner-Fin Tubes,
presented at Natl. Heat Transfer Conf., Pittsburgh, PA, August 1987; Advances ill Enhanced Heat Transfer 1987, HTDVol. 68, ASME, New York, 1987.
{1841 Chyu, M. C, and Bcrglcs, A. E., Thermal Analysis on theElectric Cylindrical Test Heater for Heat Transfer Experiments, ASME Paper 87-HT-44, presented at Natl. Heat Transfer Conf.. Pittsburgh, PA, August 1987.
11851 Reid, R. S., Pate, M. B.. and Bergles, A. E., Evaporation ofR113 Refrigerant Flowing Inside Smooth Tubes, ASME Paper
87-HT-5I, presented at Natl. Heat Transfer Conf. Pittsburgh,
PA, August 1987.
1186) Bergles, A. E., Enhancement of Convective Heat Transfer-sNewton's Legacy Pursued, presented at Polish society ofTheoretical and Applied mechanics Session on the 300th Anniversary or Newton's Principia, Szczyrk, Poland, October 1987;
Mechanika Teoretyczna i Stoswana, vol. 27, pp. 381-394,
1987.
/1871 Schlager, L. M.. Pate, M. B., and Bcrglcs, A. E.,
Warrncubcrtrugung und Druckabfall bcirn Verdampfcn undKondensieren von R22 in Horizontalcn Micro-Fin-Rohren,presented at DKV Tagung, Cologne, West Germany, November 1987; Berichtiiber die Kiilte-Klima-Tagung 1987 desDeutschen Kiilte-und Klimatechnicschen vereins. pp. 361377, Kessler Schnelldruck, Stuttgart, 1987.
11881 Bcrglcs, A. E.. Fundamentals of Boiling and Evaporation, presented at NATO ASI on Thermal-Hydraulic Fundamentals and Design of Two-Phase Flow Heat Exchangers, Povoa de Varzirn, Portugal, July 1987; Two-Phase FlowHeat Exchangers. Thermul-Hydraulic Fundamentals and Design, pp. 159-200, Kluwer, Dordrecht, The Netherlands,
1988.
1189/ Bergles, A. E.. Heat Transfer Augmentaion, presented at
NATO ASI on Thermal-Hydraulic Fundamentals and Design of Two-Phase Flow Heat Exchangers, Povoa de Varzim,
Portugal, July 1987; Two-Phase Flow Heat Exchangers.
Thermal-Hydraulic Fundamentals and Design, pp. 343-373,
Kluwer, Dordrecht, The Netherlands, 1988.
/190] Chyu, M.-C .. and Bcrglcs, A. E., An Analytical and Experimental Study of Falling-Film Evaporation on a Horizontal
Tube, J. Heat Transfer, vol, 109, pp. 983-990,1987.
11911 Reid, R. S., Pate, M. B.. and Bergles, A. E., A Comparisonor Augmentation Techniques During In-Tube Evaporation of
R-113, presented (poster) at ASME Winter Annual Meeting,
Boston, December 1987; Boiling and Condensation ill Heat
Transfer Equipment, HTD-Vol. 85, pp. 21-30, ASME, New
York,1987.

38

heattransfer engineering[192] Khanpara, J. C, Pate, M. B., and Bergles, A. E., Local Evaporation Heat Transfer in a Smooth Tube and a Micro-Fin Tube
Using Refrigerants 22 and 113, presented (poster) at ASME
Winter Annual Meeting, Boston, December 1987; Boilingand Condensation ill Heat Transfer Equipment, HTD- Vol. 85
pp. 31-40, ASME, New York, 1987.
[193] Ravigururajan, T. S., and Bergles, A. E., An Overview ofThermal Hydraulic Correlations for Internal Flow in RoughTubes, presented at 8th Miami Int. Conf. on Alternative Energy Sources, Miami Beach, FL, December 1987, Abstract
Volume 2, pp. 427-429.
[194] Ravigururajan, T. S., and Bergles, A. E., Optimization of Enhanced Heat Exchangers Including OTEC Evaporators andCondensers, presented at 8th Miami Int. Conf. on Alternative
Energy Sources, Miami Beach, FL, December 1987, Abstract
Volume I, pp. 192-193; Alternative Energy Sources VIII, vol.
I, pp. 1031-1050, Hemisphere, New York, 1989.
1195] Park, K. A., and Bergles, A. E., The Critical Heat Flux for
Horizontal Cylindrical Heaters, Energy R&D (Korean Institute of Energy and Resources), vol. 9, no. 4, pp. 16-26, 1987.
[196] Ayub, Z. H., and Bergles, A. E.. Pool Boiling Enhancementof a Modified GEWA-T Surface in Water, J. Heal Transfer,vol. 110, pp. 266-268, 1988.
[197] Chyu M.-C, and Bergles, A. E., Thermal Analysis of theElectrically Heated Cylindrical Test Section for Heat Transfer Experiments, EXfJ. Thermal Fluid Sci., vol. I. pp. 19-27,
1988.
[198] Manglik, R. M., and Bergles, A. E., Laminar Flow Heat Transfer in a Semi-Circular Tube with Uniform Wall Temperature,1111. J. Heat Mass Transfer, vol, 31, pp. 625-636, 1988.
[199] Park, K.-A., and Bergles, A. E., Ultrasonic Enhancement ofSaturated and Subcooled Pool Boiling, lilt. 1. Heal Mass
Transfer, vol. 31, pp. 664-667, 1988.
[200] Bergles, A. E., High Flux Boiling Applied to Microelectronics
Thermal Control, presented at The James W. Westwater Symposium on Boiling and Condensation, University of Illinois,
Urbana, May 6. 1988; lilt. Commun. Heat Mass Transfer, vol.
15,pp. 509-531,1988.
[201] Park. K.-A., and Bergles, A. E., Effects of Size of Simulated
Microelectronic Chips on Boiling and Critical Heat Flux, J.
Heat Transfer, vol. 110, pp. 728-734, 1988.
[202J Bergles, A. E., and Kim, C-J., A Method to Reduce Temperature Overshoots in Immersion Cooling of Electronic Devices, presented at lnterSociery Conf. on Thermal Phenomenain the Fabrication and Operation of Electronic components,
May 1988; Proc. lntersociety Calif all Thermal Phenomena
ill the Fabrication and Operation oj Electronic Components,
pp. 100--105. IEEE, New York, 1988.
[203] Tien, Y. C, Ma, C E, Lee, S. C, La, D. H., and Bergles, A.
E.. Enhanced Heat Transfer from Simulated Microchips toSurrounding Liquid of Low Volatility with Gas Jet Impingement, presented atlnl. Symp. on Phase Change Heat Transfer,
Chongqing, China, May 1988; Advances ill Phase Change
Heat Transfer, pp. 419-424, International Academic Publishers, Beijing, and Chongqing University Press, Chongqing
China, 1988.
[204] Schlager, L. M.. Pate, M. B., and Bergles, A. E., Evaporation and Condensation of Refrigerant-Oil Mixtures in a LowFin Tube, presented at ASHRAE Annual Meeting, Ottawa,
Canada, June 1988; ASHRAE Trans., vol. 94, part 2, 11761194, 1988.
[2051 Junkhan, G. H., Bergles, A. E., Nirmalan, V., and Hanno,W., Performance Evaluation of tbe Effects of a Group of

vol. 19 no. 3 1998

Turbulator Inserts on Heat Transfer from Gases in Tubes. presented at ASHRAE Annual Meeting, Ottawa, Canada, June
1988;ASHRAE Trans., vol. 94, part 2, pp. 1195-1212, 1988.
[206] Baustian, J. J., M. B., Pate, and Bergles, A. E., Measuring theConcentration of a Flowing Oil-Refrigerant Mixture with a
Vibrating U-Tube Densimeter, presented at ASH RAE Annual
Meeting, Ottawa. Canada, June 1988; ASHRAE Trans., vol.
94, part 2, pp. 571-587, 1988.
[207] Baustian, J. J., Pate, M. B., and Bergles, A. E., Measuring theConcentration of a Flowing Oil-Refrigerant Mixture with a
Bypass Viscometer, presented at ASHRAE Annual Meeting,Ottawa, Canada, June 1988; ASHRAE Trans., vol. 94, part 2,
pp. 588-60 I, 1988.
[208] Baustian, J. J., Pate, M. B., and Bergles, A. E., Measuring the Concentration of a Flowing Oil-Refrigerant Mixture
with an Acoustic Velocity Sensor, presented at ASHRAE Annual Meeting, Ottawa, Canada, June 1988; ASHRAE Trans.,
vol. 94, part 2, pp. 602-615, 1988.
[209] Schlager, L. M., Pate, M. B., and Bergles, A. E., Evaporation
and Condensation of Refrigerant-Oil Mixtures in a SmoothTube and a Micro-Fin Tube, presented at ASHRAE WinterMeeting, Dallas, TX, January t988; ASHRAE Trans., vol. 94,
part I, pp. 149-166, 1988.
[210] Baustian, J. J.. Pate, M. B., and Bergles, A. E., Measuring theConcentration of a Flowing Oil-Refrigerant Mixture: Instrument Test Facility and Initial Results, presented at ASHRAE
Winter Meeting, Dallas, TX, January 1988; ASHRAE Trans.,
vol. 94, part I, pp. 167-177, \988.
[21 I] Bergles, A. E., Enhancement of Convective Heat Transfer: Newton's Legacy Pursued, Presented at 25th Natl. Heat
Transfer conf., Houston, TX. August 1988: History of Heat
Transfer, pp. 53-64. ASME, New York, 1988.
[212J Rabas, T. J., Bergles, A. E., and Moen, D. L., Heat Transfer
and Pressure Drop Correlations for Spirally Grooved (Rope)
Tubes Used in Surface Condensers and Multistage Flash
Evaporators, presented (poster) at 25th Natl. Heat Transfer Conf., Houston, TX, August 1988; ASME Proc. 1988
Nail. Heat Transfer Conf., vol. I, HTD- Vol. 96, pp. 693-704.
ASME, New York, 1988.
[213] Bhavnani, S. H., and Bergles, A. E., An Experimental Studyof Laminar Natural Convection Heat Transfer from Wavy
Surfaces, presented (poster) at 25th Natl. Transfer Conf.,
Houston, TX, August 1988; ASME Proc. 1988 Natl. Heat
Transfer Conf., vol. 2, HTD-Vol. 96, pp. 173-180, ASME,New York, 1988.
[214] Ayub, Z. H., and Berglcs, A. E.. Nucleate Pool Boiling Curve
Hysteresis for GEWA-T Surfaces in Saturated R-113, presented (poster) at 25th Natl. Heat Transfer Conf., Houston,
TX, August 1988; ASME Proc. 1988 Natl. Heat Transfer
COllf. vol. 2, HTD- Vol. 96, pp. 515-521, AS ME, New York.
1988.
[215] Bergles, A. E., The Impact of Heat Transfer Enhancement on
Energy Conservation; The Current Status of Heat Transfer
Enhancement, keynote address at Int. Symp. on Heat Transfer Enhancement and Energy Conservation, Quangzhou,
China, August 1988; Heat Transfer Enhancement and EIIergy Conservation, pp. 1I-48, Hemisphere, New York,
1990.
[216] Ma, C. F., Tian, Y. Q., Sun, H., Lei, D. H., and Bergles, A. E.,
Local Characteristics of Heat Transfer from a Small Heater
to an Impinging Round Jet of Liquid of Larger Pr Number,presented at Int. Symp. on Heat Transfer Enhancement andEnergy Conservation, Quangzhou, China, August 1988; Heat

heat transfer engineering

Transfer Enhancement and Energy Conservation, pp. 223229, Hemisphere, New York, 1990.
[217] Ma, C. F., and Bergles, A. E., Convective Heat Transfer on
a Small Vertical Heated Surface in an Impinging Circular
Liquid Jet. presented at Second Int. Symp. on Heat Transfer, Beijing, China, August 1988; Preprints, vol. I, pp. 248255, 1988; Heat Transfer Science and Technology, pp. Hemisphere, New York, 1989.
[218] Bergles, A. E., Cooling Electronic Equipment: Past, Present,
and Future, W. Nakayama and keynote lecture at Int. Centre
for Heat and Mass Transfer XX Int. Symp. on Heat Transfer inElectronic and Microelectronic Equipment, Dubrovnik, Yugoslavia, August 1988; Heat Transfer ill Electronic and Microelectronic Equipment, pp. 3-39, Hemisphere, New York,
1990: Hladenje Elektronske Opreme: Juce, Danas, Sutra, Termotehnika, vol. 15, pp. 237-269, 1989, Bull. lnt. Centre for
Heat and Mass Transfer, vol. 4, pp. 1-37, 1990.
[219] Ma, C. F.. and Bergles, A. E., Enhancement of Immersion
Cooling of Microelectronic Devices by Gas Jet Impingement, presented at Int. Centre for Heat and Mass Transfer
XX Int. Symp. on Heat Transfer in Electronic and Microelectronic Equipment, Dubrovnik, Yoguslavia, August 1988;
Heal Transfer in Electronic and Microelectronic Equipment,
pp. 537-549, Hemisphere, New York, 1988.
[220J Park, K.-A., Bergles, A. E., and Danielson, R. D., Boiling
Heat Transfer Characteristics of Simulated Microelectronic
Chips with F1uorinert Liquids, presented at Int. Centre for
Heat and Mass Transfer Symp. on Heat Transfer in Electronicand Microelectronic Equipment, Dubrovnik, Yugoslavia, August 1988; Heat Transfer ill Electronic WId Microelectronic Equipment, pp. 573-588, Hemisphere. New York,\990.
[221] Bergles, A. E., The Role of Experimentation in Thermo-Fluid
Sciences, Plenary Lecture at First World Conf. on Experimental Heat Transfer, Fluid Mechanics, and Thermodynamics, Dubrovnik, Yugoslavia, September 1988; Experimental
Heal Transfer; Fluid Mechanics, and Thermodynamics 1988,
pp. 1-12, Elsevier, New York, 1988; Ex!'. Thermal Fluid Sci..
vol. 3, pp. 2-13, 1990.
[222] Manglik. R. M., Bergles, A. E., and Joshi, S. D., Augmentation of Heat Transfer to Laminar Flow of Non-Newtonian
Fluids, in Uniformly Heated Tubes with Twisted-Tape Inserts,
presented at First World Conf. on Experimental Heat Transfer, Fluid Mechanics, and Thermodynamics, Dubrovnik,
Yogoslavia, September 1988; Experirnental Heal Transfer;
Fluid Mechanics, and Thermodynamics 1988, pp. 676-684.
Elsevier, New York, 1988.
[223] Bergles, A. E., Some Perspectives on Enhanced Heat
Transfer-Second-Generation Heat Transfer Technology, J.
Heat Transfer. vol. 110, no. 4(B), pp. 1082-1096, 1988.
[224] Schlager, L. M., Pate, M. B., and Bergles, A. E., A comparison of 150 and 300 SUS Oil Effects on Refrigerant Evaporation and Condensation in a Smooth Tube and a MicroFin Tube, presented at ASHRAE Winter Meeting, Chicago,
January 1989; ASHRAE Trans., vol. 95, part I, pp. 387-397,
1989.
[225] Schlager, L. M., Pate, M. B., and Bergles, A. E., Heat Transfer and Pressure Drop during Evaporation and Codensationof R22 in Horizontal Micro-Fin Tubes, lilt. J. refrigeration,
vol. 12, pp. 6-14, 1989.
[226] Manglik, R. M., and Bergles, A. E., The Thermal-Hydraulic
Design of the Rectangular Offset-Strip-Fin Compact Heat
Exchanger, presented at A. L. London Symp. on Compact

vol. 19 no.3 1998

39

Heat Exchangers. Stanford. CA, March 1989; Compact Heat
Exchangers, pp. 123-149, Hemisphere. New York. 1990.
\227\ Chyu, M.-C .. and Bergles, A. E., Locating Method for
Temperature-Sensing Elements Inserted in Solid Bodies. Exp.
Thermal Fluid Sci.• vol. 2. pp. 247-297. 1989.
12281 Schlager, L. M.. Pate, M. B., and Berglcs, A. E., Heat Transfer
and Pressure Drop Performance of Smooth and InternallyFinned Tubes with Oil and Refrigerant 22 Mixtures, presented
at ASHRAE Annual Meeting, Vancouver, B. C.. June 1989;
ASHRAF: Trans., vol. 95, part 2. pp. 375-385, 1989.
1229) Bcrglcs, A. E.. The Challenge of Enhanced Heat Transfer with
Phase Change. presented at VII Congresso Nazionale sulla
Trasmissione del Calore, Florence. Italy, June 1989; Proc. VII
Congresso Nazionale sulla Trasmissione del Calore, pp. 112. Sodeta Editriee Esculapio, Bologna, Italy, 1989. 1111 J.
Heal Technol., vol. 7, no. 3-4, pp. 1-12, 1989.
12301 Schlager, L. M., Pate, M. B.. and Berglcs, A. E., Evaporation and Condensation Heat Transfer and Pressure Dropin Horizontal 12.7-mm Micro-Fin Tubes with Refrigerant
22, presented (poster) at 26th Natl. Heat Transfer Conf,and Exhibition, Philadelphia. August] 989; Heat Transfer
Equipmen: Fundamentals. Design, Applications, and Operating Problems, HTD- Vol. 108, pp. 205-214, ASME. New
York, 1989; J. Heat Transfer, vol. 112. pp. 1041-1047,
1990.
12311 Marner. W. J., and Bergles, A. E.. Augmentation of Highly
Viscous Laminar Heat Transfer Inside Tobes with Constant
Wall Temperature, Exp. Thermal Fluid Sci., vol. 2. pp. 252267. 1989
12321 Chyu, M. C; and Bcrglcs, A. E.• Horizontal-Tube FallingFilm Evaporation with Structured Surfaces. 1. Heal Transfer,vol. III, pp. 518-524.1989.
12331 Schlager. L. M.. Pate, M. B.. and Bergles, A. E.. Performanceof Micro-Fin Tubes with Refrigerant-22 and Oil Mixtures,
ASHRAF: 1., vol. 31, pp. 17-28, 1989.
12341 Bcrgles, A. E., Kim, c.-J .. Verhoeven,J. D., and Gibson. E. D.,
A Novel Enhanced Boiling Heat Sink for Immersion Cooling of Microelectronic Devices. presented at Vllth Symp.
on Heat Transfer, Warsaw, Jadwisin, Poland. October 1989;
Referutv VII S)'IIIPOzjWII Wrll1iallY Ciepla i Masv, pp. 8-16.
Polska Akademia Nauk, Komitet Termodynamiki i Spalania,
Warsuw-Jadwisin, Poland, 1989.
12351 Schlager, L. M., Pate, M. B.. and Bergles, A. E., Performance
Predictions of Refrigerant-Oil Mixtures in Smooth and Internally Finned Tubes-Part I: Literature Review, presented at1990 Winter Meeting. Atlanta, GA. February 1990; ASHRAF:
Trans., vol. 96. part I, pp. 160-169. 1990.
12361 Schlager. L. M.. Pate. M. B., and Bergles, A. E., Performance
Predictions of Refrigerant-Oil Mixtures in Smooth and Internally Finned Tubes-Part II: Design Equations. Presented at1990 Winter Meeting. Atlanta. GA, February 1990; ASHRAF:
Trans.. vol. 96, part II. pp. 170-182, 1990.
12371 Ayub Z. H.. and Bcrglcs. A. E., Nucleate Pool Boiling Curve
Hysteresis for GEWA-T Surfaces in Saturated R-113, Exp.
Thermal Fluid Sci., vol. 3, pp. 249-255, 1990.
12381 Schlager, L. M.• Pate. M. 8., and Bergles, A. E., Condensation of Refrigerant-Oil Mixtures in Smooth and Augmented
Tubes. presented at Second Int. Symp. on Condensers andCondensation. Bath. UK. March 1990; Condensers and COIIdensation, pp. 451-460, HTFS, Harwell, UK, 1990.
12391 Bhavnani, S. H., and Bergles, A. E., Effect of Surface Geometry and Orientation on Laminar Natural Convection Heat
Transfer from a Vertical Flat Plate with Transverse Roughness

40

heattransfer engineering

Elements. 111I. J. Heat Mass Transfer, vol. 33, pp. 965-981,
1990.
[240J Bergles, A. E., Transport Process in a Rapidly Changing
World, presented at NATO Advanced Study Institute on Convective Heat and Mass Transfer in Porous Media, Cesme,
Turkey, August 1990; Convective Heat and Mass Transfer ill
Po rous Media. pp. 1-4, Kluwer, Dordrecht, The Netherlands,
1990.
[241] Vandervort, C. L., Bergles, A. E., and Jensen. M. K., Ultimate
Limits of Boiling Heat Fluxes, presented at 8th Symp. of Energy Engineering Sciences, Argonne. IL. May 1990; Proc. 81h
Svmp. of Energy Engineering Sciences: Micro/Macro Studies of Multiphase Media, Argonne. IL, CONF-9001583, pp.
95-102. 1990.
[242] Manwell, S. P., and Bergles, A. E., Gas-Liquid Flow Patterns
in Refrigerant-Oil Mixtures, presented at ASH RAE Annual
Meeting. St. Louis. June 1990; ASHRAE Trans., vol. 96, part2, pp. 456-464, 1990.
[2431 Schlager, L. M., Pate M. B., and Bergles. A. E., Oil Quantity Measurements in Smooth and Micro-Fin Tubes during
Evaporation and Condensation of Refrigerant-Oil Mixtures,presented at ASHRAE Annual Meeting, St. Louis. June 1990;
ASHRAE Trns., vol. 96. part 2, pp, 465-469. 1990.
[244] Borkowski, C. A., Jensen. M. K., and Bergles, A. E., The
Computer as an Aid to Teaching Experimentation: An Example in the Thermal Sciences. presented at 1989 Frontiersin Education Conference, Binghamton, NY. October 1989;
Proc. 1989 Frontiers ill Education Conference, pp. 93-104,
IEEE. New York, 1989.
[245J Carvalho. R. D. M., and Bergles, A. E., The Influence of Subcooling on the Pool Nueleate Boiling and Critical Heat Flux ofSimulated Electronic Chips, presented (poster) at Ninth Int.
Heat Transfer Conf., Jerusalem, August 1990; Proc. Ninth1111. Heal Transfer Conf., vol. 2, pp. 289-294, Hemisphere,
New York. 1990.
[246J Armstrong, R. D., and Bergles, A. E., A Study of Enhanced
Ceramic Tubes for High Temperature Waste Heat Recovery, presented (poster) at Ninth Int. Heat Transfer Conf.,
Jerusalem, August 1990; Proc. Ninth 111I. Heal Transfer Conf.,
vol. 4, pp. 21-26, Hemisphere, New York, 1990.
[247J Berglcs. A. E., The Challenge of International Cooperationin Heat and Mass Transfer, Banquet Speech at 6th Miami Int.
Symp. on Heat and Mass Transfer. Miami, FL, December
1990; Heat and Mass Transfer: All Era of Change. vol. I,
Nova Science Publishers, Commack, NY. 1994.
[248] Schlager. L. M.. Pate, M. B., and Bcrglcs. A. E., The Effect ofHeater Thermal Properties and Thickness on the Pool Boiling Critical Heal Flux, presented at III Encontro Nacional deCiencias Tcrmicas, Itaperna, Brazil, December 1990; Proc.
3rd Brazilian Thermal Sciences Meeting (Ill ENClT), vol. II,
pp. 577-582, 1990.
[249j Reid, R. S., Pate M. B., and Bergles, A. E., A Comparison ofAugmentation of Techniques During In-Tube Evaporation of
R-113.1. Heat Transfer, vol. 113, pp. 451-458, 1991.
[250] Somerscales, E. F. c., Ponteduro, A. F., and Bergles, A. E..
Particulate Fouling of Heat TransferTubes Enhanced on Their
Inner Surface. presented at 27th Natl. Heat TransferConf. andExposition. Minneapolis, MN, July 1990; Fouling and EIIhancement Interactions, HTD- Vol. 164, pp. 17-28, ASME.
New York, 1991.
[251] Ravigururajan, T. S.. and Bergles, A. E.. Visualization of Flow
Phenomena near Enhanced Surfaces, presented at 27th Natl,Heat Transfer Conf. and Exposition, Minneapolis, MN, Julyvol. 19 no. 3 1998

1991; Foaling and Enhancement Interactions, HTD- Vol. 164,
pp. 71-75, ASME, New York, 1991.
[252J Bnavnani, S. H., and Bergles, A. E.. Natural Convection
Heat Transfer from Sinusoidal Wavy Surfaces, Wiirme-and
Stoffubertragung, vol. 26, pp. 341-349,1991.
[253] Boneuo, F., Clausse, A., Converti, J., Carvalho, R. D. M., andBerglcs, A. E., Probabilistic Interpretation of the Experimental Indicator Function in Two Phase Flow, Proc. 111I. Can! on
Multiphase Flow '91 Tsukuba, vol. 2, pp. 598-601, University of Tsukuba, Tsukuba. Japan, 1991.
[254] Carvalho, R. D. M., and Bergles, A:. E., The Use of Hot Wire
Anernornetry for Local Void Fraction Measurements in Pool
Boiling, presented (poster) at XI Congrcsso Brasileiro de Engenharia Mecanica. Sao Paulo. Brazil, December 1991; Proc.
l l th ABCM Mechanical Engineering Conf., vol. I, pp. 279282, Associacao Brasileira de Cianci as Mecanicas, 1991.
[255] Bcrgles, A. E.. Heat Transfer Enhancement-Second Generation Heat Transfer Technology. presented at XI Congress
Brasilciro de Engenharia Mecanica. Sao Paulo, Brazil.
Deccmber 1991; Preprinted for Congress. Latin Am. ApI'/.
Res., vol. 23, pp. 141-152, 1991.
[256J Bergles, A. E., Computer (Cooling), in McGraw-Hill Yearbook ofScience and Technology, 1992, pp. 83-85, McGrawHill, Ncw York. 1991.
[257J Bergles, A. E.. What Is the Real Mechanism of CHF in Pool
Boiling?, presented at Engineering Foundation Conf. on Pooland External Flow Boiling. Santa Barbara, CA, March 1992;
Pool and External Flow Boiling. pp. 165-170, ASME. New
York, 1992.
[2581 Jensen, M. K., Trewin R. R., and Bergles, A. E., Crossflow
Boiling in Enhanced Tobe Bundles, presented at Engineering
Foundation Conf. on Pool and External Flow Boiling, Santa
Barbara, CA. March 1992; Pool and External Flow Boiling.
pp. 373-379, ASME, New York, 1992.
[259] Carval ho, R. D. M.. and Berglcs. A. E., The Effects of Heater
Thermal Conductance/Capacitance on the Pool Boiling Critical Heat flux, presented at Engineering Foundation Cant". on
Pool and External Flow, Boiling, Santa Barbara, CA. March
1992; Pool and Extemal Flow Boiling. pp. 203-211, ASME,New York, 1992.
[2601 Golobic, I.. and Bergles, A. E.. Effects of Thermal Properties and Thickness of Horizontal Vertically Oriented Ribbon
Heaters on the Pool Boiling Critical Heat Flux, presented atEngineering Foundation Conf on Pool. and External Flow
Boiling. Santa Barbara, CA, March 1992; Pool and External
Flow Boiling, pp. 213-218, ASME, New York, 1992.
[261] Manglik, R. M., and Bergles, A. E., Heat Transfer Enhancement and Pressure Drop in Viscous Liquid Flows in
Isothermal Tubes with Twisted-Tape Inserts, Wiirme-ulld
Stoffiibertragung, vol. 27, pp. 249-257, 1992.
[262J Bergles, A. E.. and Bar-Cohen, A, Direct Liquid Cooling ofMicroelectronic Components, in Advances ill Thermal Modeling of Electronic Components and Systems, pp. 233-342,
ASME Press. New York, 1992.
[263] Bcrgles, A. E., Enhanced Heat TransferTeehniques for HighHeat-Flux Boiling, presented (poster) at SPIE Symp., San
Diego. CA, July 1992; Conf. on High Heat Flux Engineering,
SPIE Proc., Int. Society for Optical Engineering, Bellingham,
WA, vol. 1739, pp. 2-17, 1992.
[264J Manglik, R. M., and Bergles, A. E., Heat Transfer and Pressure Drop Correlations for Twisted-Tape Inserts in Isothermal
Tubes: Part I. Laminar Flows, presented at Natl. Heat Transfer
Conf., San Diego, CA, August 1992; Enhanced Heal Trans-

heat transfer engineering

fer, HTD-Vol. 202, pp. 89-98, ASME, New York, 1992; 1.
Heat Transfer. vol. 115, pp. 881-889,1993.
[265] Manglik, R. M., and Bergles, A. E., Heat Transfer and Pressure Drop Correlations for Twisted-Tape Inserts in Isothermal Tubes: Part II. Transition and Turbulent Flows, presented
at Natl. Heat Transfer Conference, San Diego, CA, August
1992; Enhanced Heat Transfer, HTD- Vol. 202, pp. 99-106,
ASME, New York, 1992; J. Heat Transfer, vol. 115, pp. 890896, 1993.
[266] Vandervort, C. L., Bergles, A. E., and Jensen, M. K.,
Heat Transfer Mechanisms in Very High Heat Flux Subcooled Boiling, presented at Winter Annual Meeting, ASME.
Anaheim, CA, November 1992; Fundamentals ofSubcooled
Boiling, HTD-Vol. 217, pp. 1-10, ASME, New York, 1992.
[267] Jensen, M. K., Trewin, R. R., and Bergles, A. E., Crossflow
Boiling in Enhanced Tube Bundles, presented at Winter Annual Meeting, ASME. Anaheim, CA, November 1992; TwoPhase Flow ill Energy Systems, HTD-Vol. 220, pp. 11-17,
ASME, New York, 1992.
[268] Ravigururajan, T. S.. and Bergles, A. E., Heat Transfer Enhancement of In-Tube Flow of Water at Low Temperatures,presented (poster) as Paper 92-WNHT-3 at Winter Annual
Meeting, ASME, Anaheim, CA, November 1992.
[269] Bergles, A. E., Elements of Boiling Heat Transfer, in Boilillg Heal Transfer-Modem Developments and Advances,
pp. 389-445, Elsevier, Amsterdam, The Netherlands, 1992.
[270] Ha, S., and Bergles, A. E., The Influence of Oil on Local Evaporation Heat Transfer inside a Horizontal Micro-Fin Tube,
presented at ASHRAE Winter Meeting, Chicago. January
1993; ASHRAE Trans., vol. 99, part I. pp. 1244-1255. 1993.
[271] Ha, S., and Berglcs, A. E., Local Heat Transfer Characteristics of Horizontal In-Tube Evaporation, presented at 6th Int.
Symp. on Transport Phenomena (ISTP-6) in Thermal Engineering, Seoul. Korea, May 1993; Transport Phenomena
in Thermal Engineering, vol. 2, pp. 902-909, Begell House,
New York, 1993.
[272] Bergles, A. E., and Bar-Cohen, A.. Immersion Cooling ofDigital Computers, presented at NATO Advanced Study
Institute on Cooling of Electronic Systems, Cesme, Turkey.
June J 993; Cooling of Electronic Systems, pp. 539-621,
Kluwer, Dordrecht. The Netherlands, 1994.
[273] Bcrgles, A. E., The EffectofFoulingon Enhanced Heat Transfcr Equipment. presented at ICHMT Int. Symp. on New Developmcnts in Heat Exchangers, Lisbon, Portugal, September
1993; preprinted for symposium.
[274] Zitz, J. A., and Berglcs, A. E., Immersion Cooling of a Multichip Module by Pool Boiling of FC-86, presented at Int. Electronics Packaging Conf., Binghamton, NY, October 1993;
Advances ill Electronic Packaging 1993, vol. 2, pp. 917-926,
ASME, New York, 1993.
[275] Manglik, R. M., and Bergles, A. E., Numerical Predictions of
Fully Developed Laminar Flows in Circular Segments Ducts,
presented (poster) at ASME Winter Annual Meeting, New
Orleans. LA. December 1993; General Papers on COllvecrioll,
HTD-Vol. 256, pp. 9-19, ASME, New York, 1993.
[276] Bergles, A. E., Heat Transfer Enhancement-Second Generation Heat Transfer Technology. presented at X Congresso
Nazionale Sulla Trasmissione del Calore, Genova, Italy, June
1992; Proc. X Congresso Nazionale Sulla Trasmissime delCalore, pp. 3-21, Universita degli Studi di Genova, Genova,
Italy, 1992.
[277] Manglik, R. M., and Bergles, A. E., Influence ofTwisted Tape
Generated Swirl on Single-Phase Heat Transfer, presented

vol. 19 no.3 1998

41

(poster) at First ISHMT-ASME Heat and Mass Transfer Conf.
and Twelfth Natl. Heat and Mass Transfer Conf., Bombay,
India, January 1994; Heat and Mass Transfer 94, pp. 249256. Tata McGraw-Hili, New Delhi. India. 1994.
1278] Bergles, A. E., The Influence of Fouling on Enhanced Heat
Transfer, presented at Int. Symp.l Workshop on Boiling, Condensation and Two-Phase Heat Transfer, Visakhapatnam,
India, January 1994; preprinted for symposium/workshop.
1279J Rnvigururajun, T. S., and Bergles, A. E., Visualization of
Flow Phenomena near Enhanced Surfaces, J. Heat Transfer,vol. 116. pp, 54-57, 1994.
12801 Vandervort, C. L., Bcrgles, A. E., and Jensen. M. K., An
Experimental Study of Critical Heat Flux in Very High Heat
Flux Subcooled Boiling. lilt. J. Heat Mass Transfer, vol. 37,
suppl, I, pp, 161-173, 1994.
(281) Trewin, R. R., Jensen, M. K., and Bergles, A. E., Experimental
Results of Enhanced Bundle Boiling in Binary Mixtures. 1.
Energy, Heat and Mass Transfer, vol. 16, pp. 133-146. 1994.
12821 Trewin, R. R., Jensen, M. K., and Bergles, A. E.. Pool Boiling From Enhanced Surfaces in Pure and Binary Mixtures of
R-113 and R-II. presented (poster) at 10th Int. Heat Transfer
Conf., Brighton, England. August 1994; Proc. 10th lilt. Heat
Transfer Conf., vol. 5. pp. 165-170, Institution of Chemical
Engineers, Rugby, England. J 994.
1283J Carvalho, R. D. M., and Bergles, A. E., The Pool Nucleate
Boiling Flow Patterns of Vertically Oriented, Small Heaters,
Boiling on One Side, presented (poster) at 10th Int. Heat
Transfer Cont., Brighton, England. August 1994; Proc. 10th
lilt. Heat Transfer Conf., vol. 5. pp. 25-30. Institution ofChemical Engineers. Rugby. England. 1994.
12841 Ha. S., and Bergles, A. E., Some Aspects of Experimental InTube Evaporation. presented (poster) at I Oth Int. Heat Transfer Conf., Brighton, England. August 1994; Proc. 10th lilt.
Heat TransferConf., vol. 6, pp. 187-192. Institution of Chernical Engineers, Rugby, England, 1994.
1285J Lang, S., and Bergles, A. E., Transformer Cooler Performance; Analysis and Experiment, presented at Int. Joint
Power Generation Conf., Phoenix. AZ. October 1994; Heat
Exchanger Technologiesfor the Global Environment, PWRVol. 25. pp. 131-140, ASME, New York, NY, 1994; Heat
Transfer Eng., vol. 16, no. 4. pp. 28-41,1995.
12861 Manglik, R. M., and Bcrglcs, A. E., Fully Developed Laminar Heat Transfer in Circular-Segment Ducts. Numer: Heat
Transfer, vol. 26, pp. 499-519, 1994.
(2871 Tong, W., Bergles, A. E., and Jensen. M. K., Critical Heat Fluxand Pressure Drop of Subcooled Flow Boiling in Small Diarnctcr Tubcs with Twisted-Tape Inserts, presented at ASME Int.
Congress, Chicago, November 1994; Heat Transfer ill HighHeat Flux Systems, HTD-Vol. 301, pp, 47-58. ASME, New
York, 1994; J. Enhanced Heat Transfer, vol. 3, pp. 95- I08,
1996.
12881 Manglik, R. M., and Bergles, A. E.. Heat Transfer and Pressure Drop Correlations for the Rectangular Offset Strip Fin
Compact Heat Exchanger, Exp. Thermal Fluid Science, vol.
10, pp. 171-180, 1995.
12891 MacBain, S. M., and Bcrgles, A. E., Heat Transfer and Pressure Drop Characteristics of Forced Convective Evaporation

42

heat transfer engineeringin Deep Spirally Fluted Tubing, presented at The Engineering Foundation Conf, on Convective Flow Boiling, Banff,
Canada, May 1995.
1290J Bergles, A. E.. and Somerscales, E. F. C, The Effect of Fouling on Enhanced Heat Transfer Equipment, J. Enhanced Heat
Transfer, vol. 2, pp. 157-166. 1995.
1291] Bergles, A. E., Advanced Enhancement for Heat Exchangers,
presented at Japan-U.S. Seminar on Thermal Engineering for
Global Environmental Protection, San Francisco, CA, July
1995.
[292J Ravigururajan, T. S., and Bcrgles, A. E.• Prandtl Number Influence on Heat Transfer Enhancement in Turbulent Flow ofWater at Low Temperatures, J. Heat Transfer, vol. I 17, pp.
276-282, 1995.
[293J Golobic I.. and Bergles, A. E., Some Aspects of Heater Side
Factors on Pool Boiling Critical Heat Flux. presented at Int.
Symp. on Two-Phase Flow Modelling and Experimentation.
Rome, Italy, October 1995; Two-Phase Flow Modelling andExperimentation 1995. vol. 2, pp. 873-879. Edizioni ETS.
Pisa, Italy. 1995.
Bergles, A. E.• and Jensen. M. K., Pressure Drop[294] Tong.
with Highly Subcooled Flow Boiling in Small Diameter
Tubes. presented at Int. Symp. on Two-Phase Flow Modellingand Experimentation. Rome. Italy, October 1995; Two-Phase
Flow Modelling and Experimentation 1995. vol. I, pp. 617628. Edizioni ETS. Pisa, Italy, 1995.
[295] Misale, M.. and Bergles, A. E., The Influence of Channel
Width on Natural Convection and Boiling Heat Transferfrom Simulated Microelectronic Components. presented at
Int. Symp. on Two-Phase Flow Modelling and Experimentation, Rome. Italy. October 1995; Two-Phase Flow Modellingand Experimentation 1995, vol. 2. pp. 1171-1176, Edizioni
ETS. Pisa, Italy. 1995.
[296] Berglcs. A. E.. Heat Transfer Enhancement and Energy Efficiency: Recent Progress and Future Trends, presented at Sessions on Advances in Enhanced Heat/Mass Transfer. Energy
Efficiency, and Process Integration. 1995 ASME Congress
and Exposition, San Francisco, CA. November 1995; Advallces ill Enhanced Heat/Mass Transfer and Energy Effi·
ciency, p. I, ASME. New York, 1995.
[297] Sarma, P. K., Dharma Rao, Y. and Bergles, A. E., Turbulent Film Boiling on a Horizontal Cylinder-Effectof Temperature-Dependent Properties, presented at Int.
Symp. on Advanced Energy Conversion System and Related Technologies (RAN 95), Nagoya, Japan, December
1995.
[298] Manglik, R. M., and Bergles, A. E.• Thermally Developing
Laminar Flow Heat Transfer in Circular-Segment Ducts at
Constant Wall Temperature, presented at Int. Symp. on Transport Phenomena in Thermal-Fluids Engineering, Singapore,
June 1996.
[299] Lang. S. K., and Bergles, A. E.. Transformer Cooler Performance with an Air/Water Spray, Chem. Eng. Commun.. 1996.
[300] Bergles, A. E., The Encouragement and Accommodation ofHigh Heat Fluxes. invited lecture presented at 2nd European
Thermal-Sciences and 14th UIT National Heal Transfer Conf.
Rome. Italy. May 1996.

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vol. 19 no. 3 1998