bluuebunny/crossref_metadata_2025 huggingface dataset:
Holographic Studies of Shock Waves Within Transonic Fan Rotors
Authors: Benser W. A. , Bailey E. E. , Gelder T. F.
Published: November 2010

NASA has funded two separate contracts to apply pulsed laser holographic interferometry to the detection of shock patterns in the outer span regions of high tip speed transonic rotors. The first holographic approach used ruby laser light reflected from a portion of the centerbody just ahead of the rotor. These holograms showed the bow wave patterns upstream of the rotor and the shock patterns just inside the blade row near the tip. Much of the region of interest was in the shadow of the blade leading edge and could not be visualized. The second holographic approach, on a different rotor, used light transmitted diagonally across the inlet annulus past the centerbody. This approach gave a more extensive view of the region bounded by the blade leading and trailing edges, by the part span shroud and by the blade tip. These holograms showed the passage shock emanating from the blade leading edge and a moderately strong conical shock originating at the intersection of the part span shroud leading edge and the blade suction surface. Due to a limited viewing angle, the bow waves upstream of the rotor could not be observed, and only limited details of the trailing edge shocks were obtained. The results of these studies were promising. Reasonable details of the shock patterns were obtained from holograms which were made without extensive rig modifications. These studies indicated several advancements that would give even better results. Larger viewing windows, and holographic plates would permit a wider viewing angle and give much more coverage of the regions of interest. Shorter time delay for double-pulsed holograms is also desirable. This would minimize blade movement and give clearer holograms. With these improvements of technique effective visualization of shock configurations at least outboard of part span shrouds should be possible. Accurate definition of shock configurations will aid in attainment of improved transonic fan and compressor rotors.
Schlieren Systems for Flow Visualization in Axial and Radial Flow Compressors
Authors: Philbert M. , Fertin G.
Published: November 2010

Optical setups have been designed and built at ONERA to visualize aerodynamic flows within a fixed annular cascade, a supersonic axial compressor, and a supersonic centrifugal compressor. As these setups work by reflection on the metallic surfaces carrying the blades, special devices had to be devised for each installation. In rotating machines, the rapid evolution of the phenomena necessitates, for image recording, the use of strotoscopic synchronization devices, of fast, flash-synchronized cameras, of electronic shutters and of flash lamps. The schlieren visualization of the flow, made possible by these devices, is a precious tool to define more compact machines with high compression rates and minimum losses.
Correlations Concerning the Process of Flow Deceleration
Authors: Papailiou K. D.
Published: November 2010

Correlations are used by the engineer for design purposes and/or when a theoretical calculation is missing. The purpose of this paper is to show that, applying the momentum integral equation, it is possible to derive correlations for flow situations associated with a deceleration. Four different cases are presented in the paper: (a) The case of the profile losses in a cascade of blades; (b) the case of the secondary losses in a cascade of blades; (c) the case of the turbulent shear layer before reattachment in a laminar separation bubble; (d) the case of the interaction of a shock with a turbulent boundary layer. At the same time the important factors governing these flow situations are put into evidence.
Simulation Study of Transient Performance Matching of Turbofan Engine Using an Analogue Computer to Evaluate Its Usefulness as Design Tool
Authors: Itoh M. , Ishigaki T. , Sagiya Y.
Published: November 2010

An analogue computer was designed, constructed and evaluated whether it is useful to predict dynamic response of turbofan engines or not, as design tool in development of turbofan engine. The computer was evaluated using well-known data of components performance, moment of inertia of rotors, etc., of an existing experimental two spool turbofan engine as input, and comparing the output data with transient performance data of the engine. The computer was proved to be useful to simulate dynamic response or component performance matching characteristics in transient speed condition of turbofan engines.
An Empirical Study of the Relation of Chemical Properties to Ash Fusion Temperatures
Authors: Winegartner E. C. , Rhodes B. T.
Published: November 2010

Regression analysis is used to develop equations for calculating fusion temperatures of coal ash from chemical composition, based on 1250 analyses of ash from both eastern and western coal. Standard errors for the equations are generally less than 50°F (27°C), which is the analytical tolerance of the ash fusion temperature measurements. Equations are given for eastern, western, and combined eastern and western coals. These equations: (1) provide a technique for calculating ash fusion temperatures from the chemical composition of the ash; (2) provide a method for calculating the ash fusion properties of coal blends; and (3) provide an improved understanding of the effect, significance, and interactions of ash elements with respect to the thermal properties of coal ash.
A Method of Measuring the Three-Dimensional Mean Flow and Turbulence Quantities Inside a Rotating Turbo-machinery Passage
Authors: Gorton C. A. , Lakshminarayana B.
Published: November 2010

A method of measuring the three-dimensional components of mean velocity and turbulence quantities within a rotating turbomachinery passage is developed through the use of hot wire anemometry techniques. Equations are derived which, when solved simultaneously and in conjunction with the data obtained from the hot wire anemometer measurements, will provide values for the radial, axial and tangential components of mean velocity, turbulence intensity and turbulence stress within the rotating turbomachinery passage. A three-bladed rocket pump inducer model, operating in air, was used in the experimentation. The method is very accurate and provides very useful information on the characteristics of the flow inside rotor passages hitherto unexplored.
Dry and Wet-Peaking Tower Cooling Systems For Power Plant Application
Authors: Larinoff M. W. , Forster L. L.
Published: November 2010

A new concept of power plant heat-sink system is presented which employs the combination of a conventional wet-tower and a conventional dry-tower. The purpose of this cooling system is to reduce wet cooling-tower makeup-water requirements in water-short areas. The dry tower operates all year around while the wet-peaking tower is used only above certain ambient dry-bulb temperatures. The two cooling circuits serve separate sections of a conventional, surface-type, steam condenser. Thermal performance analysis is presented for various combinations of cooling systems ranging from 100 percent wet to 100 percent dry. Annual makeup-water requirements are calculated for various sizes of towers located in 18 selected cities of the U.S.A. ranging from north to south and east to west.
Application of Phased Cooling to a Once-Through Cooling System
Authors: MacFarlane J. A. , Maples G. , Dyer D. F.
Published: November 2010

This paper describes the application of a heat dissipation technique called “phased-cooling” to the cooling of “once-through” river water used in an electric power plant. A thermodynamic model for the situation is developed and the equations applying to the model are given. The performance of the system is analyzed for a summer day in the Southeastern United States. Results of the analysis show that an economically attractive system can be built with less than half of the evaporation loss of cooling towers. This system can meet federal standards.
Practical Method for Estimating Number of Test Readings Required
Authors: Sigurdson S. , Kimball D. E.
Published: November 2010

This paper provides a method for estimating the number of readings required in order to meet a desired level of accuracy in the results of a test. The uncertainty in the accuracy in this case is due to the scatter in the data having the largest influence on the results. This scatter is caused by variations in the system whose measurements are being recorded. The method is based on published statistical tables which can be used to estimate the standard deviation of readings in a given sample using the range, the difference between the largest and smallest readings in the sample. The paper deals with a pratical approach for arriving at the required number of readings and should supply information which can be very useful to the test engineer responsible for testing. This method was developed for steam turbine performance testing and is included in the newly proposed revision of the Power Test Code for Steam Turbines, PTC 6. For this application and as used in the examples presented, the desired level of accuracy due to scatter is 0.05 percent. The method, however, is suitable for any type of test for which a specific degree of accuracy is desired.
Aerodynamic Design of Cooling Tower Drift Eliminators
Authors: Yao S. C. , Schrock V. E.
Published: November 2010

The characteristics of inertial drift eliminators of wet cooling towers are studied parametrically for their blade shapes, orientation with respect to gravity, solidity ratios, blade sizes, approaching air speed, and drift spectrum. The fundamental behavior of drift eliminators is revealed by nondimensional parameters. A method for the optimum design of an eliminator considering minimum cost versus performance is developed. This methodology can be integrated into the optimum design of the whole cooling system. An example is shown for this design approach. Suggestions on the design to improve the drainage of the collected water are given.
Forced Vibration of Tube Support Plates in Power Plant Condensers, With Friction Damping
Authors: Pigott R.
Published: November 2010

A method is given for analyzing the vibration of tube support plates in power plant condensers. The tubes are not fastened to the support plates and, therefore, their effect is simply that of a frictional restraint which is modeled as a massless elastic-plastic foundation. The technique given is an application of the Kryloff-Bogoliuboff method. The stability of the steady-state solution is also considered and it is shown that “jump” phenonmenon exist for some conditions.
Minimizing Assembly Imbalance in Turbomachine Rotors Made With Toothed Couplings: Locating Component Mass Centers
Authors: Davidson J. K.
Published: November 2010

A method is presented for locating component mass centers in turbomachine rotors made with toothed couplings. In the paper are described the geometrical relationships that would permit one to assemble a turbomachine rotor with predictive knowledge about component mass center locations and thereby have more specific knowledge about rotor mass distribution than is now available. Components are modeled both with one and with two lumped masses. The method requires that the components be balanced individually and that the residual imbalance be measured.
A History of the ASME Fuels Division
Authors: Sherman Ralph A.
Published: November 2010

In this paper Mr. Sherman traces the history of the ASME Fuels Division. He describes the founding and the early years of the Fuels Division and recalls the various meetings sponsored by the Fuels Division; he then describes the advances in fuels technology that have occurred since the formation of the division. Mr. Sherman is a contemporary of most of the persons mentioned here, and the paper is sprinkled with personal items relating to the stalwarts of the Fuels Division.
The Use of Plastic Cold Flow in the Development of an Externally Connected Transducer for Recording Pressure-Time Histories of Diesel Fuel Injection Phenomena and Its Application in Fault Diagnosis
Authors: Heggie W. S.
Published: November 2010

An investigation of possible methods for obtaining a pressure-time history of the diesel fuel injection cycle was conducted, with the object of producing a rugged externally connected pressure transducer. A resistance technique that discriminates against characteristics not directly associated with dynamic pressure was developed and the resulting principles incorporated into the design of a compact transducer [1]. In order to eliminate the necessity of cementing a resistance element directly to the high-pressure line, a technique using the cold flow of cured resin held captive in a steel enclosure was developed. This has resulted in an instrument of equal sensitivity and fidelity which may be installed in the field by personnel without specialized training. Diagnostic techniques applied to the analysis of diesel fuel injection health are described that are considered to have practical field application, using an externally connected transducer. No numerical measure is required, the method being based on comparison of fault signatures with a healthy master. The signature is considered to contain a definite quantity of criteria evaluated by a defined series of qualities resulting in a less nebulous approach than that of random comparison by superimposure. Nine of the most common diesel fuel injection faults are induced, checked for repeatability, and used as representative examples to illustrate the method.
Measurements of the Performance of an Air Turbine Stage at Positive and Negative Mass Flow and Rotational Speed (Four-Quadrant Characteristics)
Authors: Bammert K. , Zehner P.
Published: November 2010

In the mass flow range −1.3 ≤ m/mN ≤ + 1.3 (N = nominal point) and in the speed range −1.0 ≤ n/nN ≤ +1.0 the four-quadrant characteristic of a turbine stage was completely measured. A turbine stage delivers power only at a positive speed above a certain mass flow rate and at very low negative speed and negative mass flow. In all other ranges it absorbs power. The power requirement is very high in the case of positive mass flow and negative speed. At 80 percent of the nominal mass flow and negative nominal speed the power absorbed amounts to 2.5 times the nominal power. The torque curves are very smooth. The standstill torque at nominal mass flow amounts to 2.1 times the nominal torque. At a very low mass flow the turbine works as a compressor. The four-quadrant characteristics can be represented in the form of φ, ψ curves.
Progress on Ceramic Rotor Blade Development for Industrial Gas Turbines
Authors: Andersson C. A. , Bratton R. J. , Cohn A. , Sanday S. C. , Lange F. F.
Published: November 2010

This paper reviews progress made in the first year of a three-year program sponsored by EPRI to design and test ceramic root attachments, leading to the full development of ceramic rotor blades and cantilevered vanes intended for industrial gas turbines. Initial work has focused on a rotor blade attachment design. The specific rotor configuration chosen for development consists of a cooled low-alloy steel disk, a cooled intermediate super-alloy attachment piece, an uncooled ceramic blade, and the provision for a compliant interface at the ceramic/metal root attachment. A new root attachment design, in which the root and groove are curved in their transverse and longitudinal directions, is presented. Room temperature spin tests of dovetail root forms have provided encouraging results and indicate that continued development is warranted.
Operating Experience and Sodium-Water Reaction Testing in the Large Leak Test Rig
Authors: DeBear W. S. , Neely H. H.
Published: November 2010

The Large Leak Test Rig (LLTR) and its role in providing information on the consequences of large sodium-water reactions in sodium-heated steam generators is described. Facility startup problems and subsequent operating experiences are discussed. Instrumentation and data acquisition methods are identified and typical data from initial tests using the 30-MWt Modular Steam Generator (hockey-stick steam generator) as a test article are presented. Information also is included on post-test inspection methods, equipment, and results. Facility modifications to permit testing of steam generator geometries, systems, and equipment more nearly prototypic of those for large LMFBR’s are described.
The Tubesheet Analysis Method in the New HEI Condenser Standards
Authors: Bernstein M. D. , Soler A. I.
Published: November 2010

The new Heat Exchange Institute (HEI) condenser standard [1] provides a method for tubesheet analysis. The historical background of this method is reviewed. The structural design problem of a rectangular tubesheet is described. A condenser tubesheet is seen to be a partially perforated plate on an elastic foundation, with the tubes comprising the foundation. The hydrostatic pull from the waterbox and surface pressure on the tubesheet are the dominant loads. Irregular tube patterns and variation in edge boundary conditions make solution of the plate problem difficult. The HEI proposes a simplified approximation: a narrow strip of tubesheet with its supporting row of tubes, analyzed as a beam on an elastic foundation. A discussion is presented of the assumptions required, allowable stress criteria, and the uncertainties involved. A preloading device is described. Some suggestions for future work are made.
Low NOx Combustion of Paraho Shale Oil in a 45 MW Utility Boiler
Authors: Jones D. G. , Mansour M. N.
Published: November 2010

Combustion tests of crude Paraho shale oil (0.7 percent sulfur and 2 percent nitrogen) were conducted in a 45 MW boiler equipped with six frontface mounted burners each rated at 85 million Btu/hr. Shale oil was blended in various proportions with low sulfur oil and natural gas so that the sulfur content of the fuel did not exceed 0.5 percent. The fuel piping system was modified to allow blending the fuels in the furnace, and this blending technique was called dual fuel combustion. NOx emissions were compared using tank blending and dual fuel combustion, and it was found that significant levels of NOx reduction were obtained using dual fuel combustion. This result was confirmed during further testing of the two blending methods at various combustion stoichiometries using both conventional and steam-atomized low NOx burners. The maximum reductions in NOx emissions occurred during fuel-rich combustion of shale oil in the bottom row of burners followed by combustion of a low-nitrogen fuel in the top row of burners.
Small Perturbation Analysis of Nonuniform Rotating Disturbances in a Vaneless Diffuser
Authors: Inoue M. , Cumpsty N. A.
Published: November 2010

The behavior of the distorted flow discharged from a centrifugal impeller within a vaneless diffuser is examined theoretically by assuming small disturbances to a main flow. The inlet static pressure distribution is found in the calculation and allowance is made for circumferential nonuniformity in the relative flow angle. The flow is treated as incompressible and inviscid. The analysis shows that the decay of irrotational disturbances is more rapid with increasing disturbance wave number (e.g. more impeller blades) and the effect of the main flow condition on this behavior is very small. With rotational disturbances, however, the decay is slower than in the irrotational case and the effect of wave number is less. However, the phase angle between radial and tangential velocity fluctuations is found to have a strong influence on the decay processes for rotational disturbances. The present small perturbation theory is compared with the well-known Dean and Senoo theory which assumes that the relative flow angle is circum ferentially uniform. The comparison shows that the present theory predicts results very similar to the Dean and Senoo theory for impellers with large blade numbers (>20). For small numbers of blades the large circumferential nonuniformity in relative flow angle, appears at smaller radii and the inaccuracy of the Dean and Senoo theory becomes pronounced.
Study of Bolted Joint Integrity and Inter-Tube-Pass Leakage in U-Tube Heat Exchangers—Part I: Analysis
Authors: Singh K. P.
Published: November 2010

“Three element bolted joints,” consisting of an unstayed tubesheet sandwiched between two tapered hub flanges, find extensive use in U-tube type heat exchangers. A comprehensive analysis technique is herein developed to investigate the structural characteristics of such joints. Design strategies to reduce stress levels in the tubesheet and the flanges are proposed. In particular, the concept of “controlled” metal-to-metal contact beyond the bolt circle between the mating surfaces is introduced and explored in depth. The solution is readily programmed on a digital computer for application in analysis oriented design evaluation and optimization studies.
Improvement of Seasonal Efficiency of Residential Heating Systems
Authors: Janssen J. E. , Bonne U.
Published: November 2010

Recent studies have shown the seasonal efficiency of oil-fired residential heating systems to be in the range of 55–75 percent compared to steady-state efficiency of 80 percent or greater. A digital model using measured input data was used to compute the on period flue losses, the off period flue losses and the losses due to combustion induced building infiltration. Excess capacity in existing systems and new construction is shown to increase fuel consumption but decrease electric power consumption in oil-fired warm air furnaces. Excessive furnace capacity is generally undesirable, but if the cost of electric power is high compared with the cost of fuel oil, there is an optimum amount of excess capacity. The use of outdoor air for combustion and draft control (sealed combustion system) is shown to be beneficial sometimes, but may incur a cost penalty under other conditions.
Use of a Tracer to Determine Contribution of a Power Plant to Suspended Particulate Levels
Authors: Frankenberg T. T. , Collins G. F. , McGrail D. W.
Published: November 2010

The problem of determining the percentage contribution of a single power plant to ambient levels of total suspended particulates, when there are many sources of identical particulates in a community, has been approached by injecting a gas tracer (SF6) into the stack effluent of the power plant. On the premise that small particles leaving the stack after an electrostatic precipitator are dispersed in the same manner as a gas, a simple dilution ratio between gas emitted to gas captured is applied to particulates emitted to obtain the contribution to total particulates captured by high-volume air samplers. Tracer tests at the Kanawha River plant of the Appalachian Power Company indicated the plant’s contribution to total suspended particulates was below 10 percent of the total concentration observed in the community. This value was further substantiated when similar results were obtained by multiple regression analyses between stack emissions, wind speed, wind direction, and observed total suspended particulates.
An Examination of The Influence of Ash on The Combustion Characteristics of Anthracites
Authors: Bryers R. W. , Kerekes Z.
Published: November 2010

There is growing interest on the international scene in the use of high-ash anthracites as fuel for generation of steam and production of energy. The formation of mineral glazes has been reported on certain high-ash anthracites, thus inhibiting the combustion process and causing high carbon losses. To determine the degree to which these mineral glazes may influence the combustion characteristics of other anthracites, a study was made of anthracites collected from various locations in the world. Conventional analytic techniques, as well as thermal shocking tests, reactivity tests, and thermal analysis, were used to predict glaze formation and its influence on combustion. It is concluded that by carefully controlling coal fines, combustion can be improved and the formation of mineral glazes can be avoided in high-ash coals.
Thin Film Conducting and Semiconducting Resistance Thermometers for Surface Temperature Measurement
Authors: Hannemann R. J.
Published: November 2010

The accurate determination of surface temperatures, especially during high conductance processes such as condensation or boiling, without affecting the heat transfer phenomena under study, is a challenging experimental task. The present work describes the fabrication and characteristics of two unique types of surface thermometers produced using microelectronic thin film technology. One uses titanium in a meandering pattern to measure surface average temperatures, while the other, using germanium, was designed for point measurements and rapid transient response. An application to experiments involving dropwise condensation of steam is considered in detail.
A Study of the Low Cycle Fatigue Characteristics of Annealed AISI 347 Stainless Steel And Overaged 6951-T6 Aluminum Push-Pull Specimens
Authors: Friedericy J. A. , Graves R. F.
Published: November 2010

In a cyclic application the Neuber theory becomes the Wetzel-Morrow approach. The Neuber theory for stresses and strains in a notch is extended to apply to specimens for which the nominal stresses and strains in the material in the field adjacent to the notch may exceed the elastic limit. Also, when the cyclic nominal stresses and strains exceed the elastic or proportional limit of the materials, this extension can be applied if a mechanism external to the nominal stress field is applied to cause the stress field to change in a predetermined manner for each successive cycle. In the case of a notched push-pull specimen, the external mechanism would be a tensile test machine and the field adjacent to the notch would be that of the nominally induced stresses and strains by means of the machine. The state of stress and strain in the notch is the result of the shape and size of the notch as well as the nominal stresses and strains adjacent to the notch. A supporting test program is discussed which dealt with the low cycle fatigue testing of two metals, AISI 347 stainless steel and 6951-T6 aluminum. A push-pull specimen was used which was designed to handle fully reversed cyclic loads from 100 cycles on up. Both fatigue and cyclic stress-strain tests were performed. The strain ranges predicted by the extended theory were inserted in the Universal Slopes equation and the cyclic lives of the specimens at various applied stress levels were determined, including those exceeding the elastic limit of the material. Good correlation was obtained between theory and experiment at the temperature levels tested. The steel specimens were tested at room temperature and 1000°F (537°C) and the aluminum specimens at room temperature and 300°F (149°C).
Further Developments in the Aerodynamic Analysis of Unsteady Supersonic Cascades—Part 1: The Unsteady Pressure Field
Authors: Verdon J. M.
Published: November 2010

This paper presents, in two parts, a theoretical investigation of the aerodynamic response produced by an oscillating cascade placed in a supersonic stream with subsonic axial velocity component. Predictions are based on the successive solution of two linear boundary value problems which treat the velocity potential and the pressure, respectively, as basic dependent variables. A solution for the potential has been reported earlier and is used here to provide upper surface blade pressure distributions. This information serves as a boundary condition for the second problem. The solution for the unsteady pressure field, described in Part 1, is obtained by a construction procedure which parallels that used earlier to determine the potential. With the present procedure, blade pressure difference distributions and aerodynamic coefficients are accurately and efficiently determined for both subresonant and superresonant blade motions. Supersonic resonance phenomena and selected numerical results are discussed in Part 2 of the paper.
Applications of a Scattering Spectrometer System for Marine Aerosol Measurement
Authors: Shen C. N. , Mihalek E. W.
Published: November 2010

A newly developed instrument has been successfully evaluated and applied to the measurement of marine aerosols. The instrument, known as the Scattering Spectrometer System (SSS), utilizes coherent scattering of laser radiation to size marine aerosols in flight and produce size distribution data in real time. Compared to current methods of using source cascade impactors, the SSS was found superior in terms of resolution, data reduction simplicity, and real-time capability. The application of the SSS at the Naval Air Propulsion Test Center (NAPTC) includes real-time facility diagnostics, control, and calibration. Novel information concerning aerosol separators has also been uncovered using the SSS.
Application of a Class of Distribution Functions to Drop-Size Data by Logarithmic Least-Squares Technique
Authors: Tishkoff J. M. , Law C. K.
Published: November 2010

The approximation of spray drop-size data by the Nukiyama-Tanasawa, Rosin-Rammler, and Griffith Comminution functions are studied. A generalized function also was used. All functions except the Rosin-Rammler were applied to spray data with a logarithmic least-squares technique. The generalized function matched the data most accurately, but digital computer programming was necessary. The Griffith function was only slightly less accurate and did not require computer calculations. Estimates of mean diameters for a spray sample with all three functions were made by direct numerical integration.
Effects of Fluid Leakage on Performance of a Centrifugal Compressor
Authors: Mashimo T. , Watanabe I. , Ariga I.
Published: November 2010

Fluid loss caused by leaks through the impeller tip clearance was investigated for a centrifugal compressor. Operating conditions, Reynolds number, and clearance were varied independently during the experiment. It was found that the average compressor performance would be reduced by about 4 percent when the relative clearance was increased from 0.0125 to 0.125 and the resulting leakage loss was dependent on the Reynolds number, the tendency of which was just opposite in case of wall friction loss, as was well-known. Moreover, a determination of the leakage loss coefficient was made as a function of the relative clearance, relative leak level and the Reynolds number as the result of this experiment.
Annular Diffuser Performance for an Automotive Gas Turbine
Authors: Japikse D. , Pampreen R.
Published: November 2010

A series of experimental tests and computational analyses are reported for two automotive gas turbine diffusers. The diffusers include an interstage and an exhaust diffuser plus collector. The diffuser models were tested at Reynolds numbers and inlet blockage levels characteristic of the engine operating conditions. A rig test of the interstage diffuser is also reported. Inlet swirl and Mach number were systematically varied in the model tests. Good recovery was found for each diffuser at zero swirl. Recovery degraded at high swirl for the interstage diffuser. The exhaust diffuser with a double discharge collector showed little sensitivity to inlet swirl. Flow visualization indicates that the interstage diffuser was separated at modest swirl levels, at least in the model test. Pressure recovery in the rig (with upstream rotor and downstream stator) was found to be greater than in the model test (using “clean” inlet conditions). Comparisons between measured wall pressures and calculations provide further basic insights.
A Design Point Correlation for Losses due to Part-Span Dampers on Transonic Rotors
Authors: Roberts W. B.
Published: November 2010

The design-point losses caused by part-span dampers were correlated for 21 transonic axial-flow fan rotors that had tip speeds varying from 350 to 488 meters per second and design pressure ratios of 1.5 to 2.0. The additional loss attributable to the damper and the total region along the blade height influenced were correlated with selected aerodynamic and geometric parameters. The maximum damper loss correlated well with the mean inlet Mach number at the damper location, the geometric parameters of leading- and trailing-edge damper radius normalized by mean passage height and damper aerodynamic chord, respectively, and the aerodynamic loading parameter of the blade camber divided by the solidity at the damper location. The region of damper influence extended over a mean passage height of the order of 10 to 15 times the maximum damper thickness.
Liquid-Coupled Indirect-Transfer Exchanger Application to the Diesel Engine
Authors: Eastwood James C.
Published: November 2010

The efficiency of turbocharged diesel engines can be increased by cooling the charge air. This paper presents a design approach for liquid-coupled indirect-transfer heat exchanger systems to perform the air-cooling function. The two advantages most commonly cited for this approach to charge-air cooling are (1) the heat exchangers involved are easily packaged so that their shapes can be controlled by judicious design, and (2) simple gas ducting allows for compact machinery arrangements and relatively low charge-air pressure drop. An analytical approach to the design of liquid-coupled indirect-transfer heat exchanger systems is presented. Performance curves are constructed on the basis of this analysis. Four important design conditions are evident from the observation of these performance curves including (1) the relative capacity rate combination of the three fluids (ambient air, coupling liquid, and engine charge-air) which yields the highest overall effectiveness, (2) an optimum coupling-liquid flow rate, (3) the relative effectiveness distribution for each of the two component heat exchangers (hot and cold components), and (4) a broad design range for the optimum area distribution between the hot and cold exchangers. These performance curves serve as a guide for the design of a liquid-coupled charge-air cooling system.
Corrosion and Deposits from Combustion of Solid Waste—Part VI: Processed Refuse as a Supplementary Fuel in a Stoker-Fired Boiler
Authors: Krause H. H. , Vaughan D. A. , Cover P. W. , Boyd W. K. , Olexsey R. A.
Published: November 2010

The utilization of shredded and magnetically separated municipal refuse to supplement high-sulfur coal as fuel in a stoker-fired boiler was investigated, using the facilities of the Columbus, Ohio, Municipal Electric Plant. Corrosion probe exposures were used to show the effectiveness of cofiring with high-sulfur coal to reduce chloride corrosion of boiler tube metals by refuse. Reduced emissions of SO2 from the high-sulfur coal also resulted from dilution of the coal with refuse and by action of alkaline components of the refuse. It was demonstrated that 700 hr corrosion rates with refuse and high-sulfur coal were 5–10 times less than those with bulk refuse burning, and approximated those from coal alone. In some runs sulfur dioxide emissions were reduced by about ten percent more than the refuse dilution factor. The cofiring with refuse had no significant effect on grate ash composition, but the ash fusion temperature was lowered about 100°F.
Optimization of Power Absorption From Sea Waves
Authors: Baz A. , Ezz M. , Bayoumi M. S.
Published: November 2010

This article presents a generalized procedure for selecting rationally the design parameters of a simple wave power absorption system. The system utilizes a tethered-symmetrical float which rides the sea waves and transmits the wave energy to a viscously damped load. The optimum load levels corresponding to the different sea states are determined, for several float geometries, in order to maximize the overall efficiency of wave-power conversion. The optimum float dimensions are constrained to guarantee that the float will not leave the wave crest during its upward travel or sink below the wave trough as it goes downward. These constraints, if overlooked, as has been the case so far in the literature, result not only in improper functioning of the system but also in values of the conversion efficiency higher than reality. The developed procedure predicts also, for different float configurations, the limits that, if satisfied, can guarantee that the system would operate at its maximum possible efficiency irrespective of the sea wave conditions. Therefore, the material presented in the study can be extremely useful in designing efficient wave power absorbers which would help in capturing the vast amount of the renewable and nonpolluting sea wave energy.
National Strategic Crude Oil Storage in the Weeks Island Dome Salt Mine—Part I: Geotechnical Evaluation
Authors: Mahtab M. A. , Lamb D. W. , Van Sambeek L. L. , Gill J. D.
Published: November 2010

This paper, the first in a series of two, presents the results of a geotechnical evaluation of the Weeks Island dome salt mine. The purpose of the evaluation was to confirm the suitability of the underground facility for the long-term storage of crude oil under the Federal Energy Administration’s Strategic Petroleum Reserve Program. The Weeks Island mine, currently operated by the Morton Salt Company, is located in a salt dome on the Gulf Coast south of New Iberia, Louisiana. The mine has two levels of workings, at depths of approximately 185 and 245 m (600 and 800 ft) with development by the room-and-pillar mining technique. Geologic features of interest within the mine include zones of vertical banding and folding, shear zones, and blowouts. Field testing indicated that the salt mass is, for all intents and purposes, impermeable. Brine and oil leaks and gas seeps were examined and thought to be localized phenomena that did not affect mine stability and should not affect crude oil containment. The 23-m- (75-ft-) high pillars are generally intact with minor to severe spalling, generally in older areas of the mine. The mine roof exhibits no signs of distress or failure. Based on the overall results of the geotechnical and rock mechanics evaluations, the existing salt mine facility at Weeks Island was certified as suitable for the long-term storage of crude oil.
Marine Riser Vibration Response Determined by Modal Analysis
Authors: Dareing D. W. , Huang T.
Published: November 2010

Marine riser response calculations are usually based on finite element or finite difference methods. This paper outlines the modal analysis method as an alternate approach for calculating marine riser time-dependent stresses. An example problem shows that five natural vibration modes give acceptable convergence and engineering accuracy. Dynamic response calculations are, therefore, greatly simplified as only a limited number of eigenvalues and eigenfunctions are needed. In addition, the time-dependent part of the solution can be determined from elementary single-degree-of-freedom-type equations.
Practical Guide to the Evaluation of the Metering Performance of Differential Producers
Authors: Halmi D.
Published: November 2010

All commonly used differential producers are reviewed and grouped according to their typical metering performance. Metering characteristics are correlated with hydraulic shapes. Guidance is provided for the typical performance analysis of any particular differential producer, in fact, for any kind of flow metering device.
A Comparison of the Multi-Venturi Meter to Other Low-Loss Fluid Meters
Authors: Klomp E. D. , Sovran G.
Published: November 2010

A comparison of the multi-venturi type meter with other fluid meters has been made. A multi-venturi type meter is one having two or more venturis cascaded in such a manner that the discharge plane of smaller venturis is positioned in the throat of larger venturis. Although the concept of venturi cascading dates back to around 1880, its unique potential in general mass-flow-rate measurement applications has not been exploited. The primary advantages of the multi-venturi type meter are that it generates significantly less loss than conventional venturis, particularly at high signal magnifications, and has a much broader flow range. As a result of the latter characteristic, a single multi-venturi meter could be used to replace two or three conventional flow meters in some fluid-metering applications.
The Splitting of Drops and Bubbles by Turbulent Fluid Flow
Authors: Sevik M. , Park S. H.
Published: November 2010

The work of Hinze concerned with the splitting of drops and bubbles by turbulent flow has been extended. In particular, the breakup of air bubbles in the adjustment region of a high Reynolds number water jet has been observed. A critical Weber number of 1.3 was obtained from these experiments, whereas Hinze calculated a value of 0.59 based on tests involving the dispersion of various immiscible liquids. It was found that both Weber numbers could be predicted theoretically by considering the resonances of the liquid drops or gas bubbles.
Application of Linearized Friction Impedance Models to Complex Fluid Systems
Authors: Hillman H. F. , Kerkam B. F. , Poel G. D.
Published: November 2010

Results of correlating system frequency response test data with analytic data are presented. The test data are from four complex systems, incorporating series and parallel piping configurations and dynamic components, flowing liquid or gas in the turbulent and laminar regime. Distributed parameter transmission line theory is used to develop the system mathematical models. Analytic results from linear and nonlinear laminar flow friction models are compared. It is shown that the correlation between pressure transfer functions determined from test and linear analytical models is satisfactory to predict system frequency response modes, to explain unanticipated test results, and to predict response of systems during design studies.
A Note on the Calculation of Supercavitating Hydrofoils With Rounded Noses
Authors: Furuya O. , Acosta A. J.
Published: November 2010

Practical supercavitating hydrofoils have rounded leading edges for mechanical strength. The prediction of pressures near the leading edge of such hydrofoils by linearized free-streamline theory fails because singularities are usually required there by the theory. A simple method based on singular perturbations of avoiding these difficulties for hydrofoils which have parabolic noses but an arbitrary profile downstream of the leading edge is presented. The results of such a computation on a hydrofoil with a parabolic profile and with fixed cavity separation near the leading edge radius are shown and are compared with an exact free-streamline theory. The agreement is excellent.
Effects of Curvature on Two-Dimensional Diffuser Flow
Authors: Parsons D. J. , Hill P. G.
Published: November 2010

The effects of curvature on diffusers have been studied experimentally and analytically. Measurements of wall pressures and boundary layer velocities have been made in three test diffusers of zero or mild curvature, in which the flow is not separated. The straight diffuser results were in very good accord with the results of flow calculations based on the Stanitz and Moses methods for treating the potential core and boundary layer regions, respectively. The curved diffuser flow measurements indicated pronounced effects of curvature on pressure and velocity distributions. Effects of curvature on boundary layers are ascribed to shear stress modification, and shown to be roughly predictable using a linear mixing length – Richardson number correlation.
Performance of Low-Aspect-Ratio Diffusers With Fully Developed Turbulent Inlet Flows: Part II—Development and Application of a Performance Prediction Method
Authors: McMillan O. J. , Johnston J. P.
Published: November 2010

An analytical method of the integral type is developed to allow prediction of performance in unstalled, straight, two-dimensional rectangular diffusers of aspect ratio less than approximately 0.5. The inlet flow is fully developed and turbulent. The results predicted by this method compare favorably to the data of Part I and to other relevant cases. The method has been applied to extrapolate performance trends to a relatively wide range of related, but untested, geometries and conditions.
A Note on the Unsteady Cavity Flow in a Tunnel
Authors: Kim J. H. , Acosta A. J.
Published: November 2010

The unsteady internal cavitating flow such as the one observed in a pump or a turbine is studied for a simple two-dimensional model of a base-cavitating wedge in an infinite tunnel and it is shown how the cavitation compliance can be calculated using the linearized free streamline theory. Numerical values are obtained for the limiting case of a free jet. Two important features are: First, the cavitation compliance is found to be of complex form, having additional resistive and reactive terms beyond the purely inertial oscillation of the whole channel in “slug flow.” Second, the compliance has a strong dependence on frequency.
Modeling of Flow-Induced Vibrations in Heat Exchangers and Nuclear Reactors
Authors: Beavers G. S. , Plunkett R.
Published: November 2010

This paper discusses the appropriate scaling factors for the modeling of the fluid-mechanical interaction of complex structures. The possible mechanisms of flow-excited vibration are described, and scaling parameters are derived from considerations of the mechanical and fluid systems. The paper is particularly concerned with the flow-induced vibrations of banks of cylinders in single phase, high Reynolds number, turbulent, cross flow, as occur for example in light water nuclear reactors and heat exchangers. It is concluded that the modeling of the tube banks in light water nuclear reactors will involve a mismatch of Reynolds number, but that the major phenomena of fluid-solid interaction in the single-phase flow region will probably be closely replicated if the Reynolds number is high enough so that the entering flow is turbulent and if the scaling ratio is not too large.
Velocity Measurements in Wet Steam Flows by Laser Anemometry and Pitot Tube
Authors: Crane R. I. , Melling A.
Published: November 2010

Velocities up to 200 m/s in condensing steam flows have been successfully measured using a laser Doppler anemometer, without artificial seeding. The performance of the system is described and results are compared with simultaneous pitot tube measurements. The discrepancy between the alternative methods used here for converting pitot pressure to velocity in subsonic wet flow becomes greater at higher speeds; extension of this work is discussed, with the objective of calibrating pitot tubes for use at high subsonic and low supersonic speeds encountered in low pressure turbines.
Flow Regimes in Two-Dimensional Ribbed Diffusers
Authors: Stull F. D. , Velkoff H. R.
Published: November 2010

Water table flow visualization tests of a straight wall diffuser and corresponding ribbed diffuser were conducted over a wide range of total divergence angles and diffuser length to throat width ratios. Rib parameters such as inter-rib cavity depth to width ratio, inter-rib cavity width, rib thickness, and number of ribs were varied, as well as rib contour. Motion pictures were obtained of the secondary flow patterns occurring within the inter-rib cavities, and hot film measurements were made to determine the extent of velocity fluctuations induced by the cavities. In general, the addition of ribs increased the no-appreciable stall regime.
Review—Transition in Nonreversing Oscillating Boundary Layers
Authors: Loehrke R. I. , Morkovin M. V. , Fejer A. A.
Published: November 2010

Literature on transition in oscillating boundary layers is relatively recent and confusing. The paper first reviews the current thinking on transition in steady boundary layers and on the role of stability theory. The reader is then provided with a background on oscillating boundary layers. The various reports of transition in such boundary layers are analyzed and clarified. The concept of excited wave packets, moving downstream through the “pulsating” boundary layer and cumulatively growing or decaying, largely in response to the transient vorticity distribution, appears to unify much of the data. Recent experiments, designed to test the ingredients of the concept, are reported. Other forms of transition are discussed and their probable occurrence in the domains of interest to practical engineers is mapped out.