bluuebunny/crossref_metadata_2025 huggingface dataset:
Calculated Design Data for the Multiple-Disk Turbine Using Incompressible Fluid
Authors: Lawn M. J. , Rice W.
Published: November 2010

Earlier analyses of the laminar radially inward throughflow of Newtonian incompressible fluid between parallel corotating disks have been used to calculate the performance of multiple-disk turbines using such flow passages as the rotor. Such turbines are characterized by certain dimensionless parameters and a large number of computerized calculations has enabled preparation of turbine performance maps for turbines idealized as having no losses external to the rotor (except for assumed zero pressure recovery in the turbine exhaust). These maps show the quantitative dependence of turbine efficiency, total pressure and delivered power on the turbine geometry and speed, the turbine nozzle direction and pressure drop, and on the fluid properties; full admission around the periphery of the rotor is assumed. Conventional loss information for the nozzles, and conventional bearing, seal and “disk friction” loss information, must be applied in the design process to provide prediction of actual turbine performance and comparison with conventional turbines.
Pulse Propagation in Distensible Viscous Fluid Lines
Authors: Jayasinghe D. A. P. , Leutheusser H. J.
Published: November 2010

Paper deals with elastic waves which may be generated in quiescent fluid by displacement of the surrounding flow boundary. In particular, the piston problem of induced laminar motion in waveguides of circular cross section is treated analytically by means of an “extended” version of the Iberall model of fluid transients. It yields closed-form solutions for the arbitrary pressure response of semi-infinite, distensible waveguides containing compressible Newtonian fluid. The solutions account for elastic as well as inertial effects of the flow boundary, and reveal several new properties of signal propagation in tubes.
The Momentum-Integral Equation for a Boundary Layer With Turbulence or Ordered Unsteadiness in the Free Stream
Authors: Horlock J. H. , Evans R. L.
Published: November 2010

The two-dimensional momentum integral equation is derived for the case where free-stream turbulence or ordered unsteadiness exist. It is shown that extra terms may arise, of which one, the shear stress at the edge of the boundary layer, is important.
Atmospheric Tests of a Variable Combustor Geometry for Reducing Gas Turbine Emissions
Authors: Saintsbury J. A. , Sampath P.
Published: November 2010

Current concern with reduction of pollution from combustion systems resulted in a research program being undertaken to evaluate the potential of variable combustor geometry for reducing emissions from an annular reverse flow gas turbine combustor. A device which simulated a variable baffle in the annulus surrounding the combustor was investigated. Results indicated a good potential for this approach, if the combustor was specially developed for low emissions. The fluid dynamics of this concept were investigated in a model using flow visualization techniques. The hot tests under this program were carried out at atmospheric pressure with full simulation of combustor flows. Significant reductions in emissions and corresponding improvements in combustion efficiency were observed when a baffle was incorporated in the combustion system. It is recognized that all important pressure effects are absent in this work, but a subsequent program is planned to demonstrate the variable geometry concept on an engine over a full range of operation.
Measurements of Mean Velocity and Mass Exchange in a Separated Recirculating Flow
Authors: Schofield W. H. , Keeble T. S.
Published: November 2010

Experimental measurements were taken in a closed, recirculating, turbulent separated flow. The experiments were made to elucidate the mass and momentum exchange mechanisms between the throughflow and the recirculating flow in a combustor that had previously been developed for burning heavy fuels without a flame tube. Mean velocity measurements are presented for the cold flow field and these are used to derive a detailed streamline pattern. The three-dimensional shear layer surface that divides the recirculating flow from the throughflow is analyzed in detail and the variation of momentum exchange coefficient along its development length is derived. Mass exchange data show that the variation of mass transport along the mixing layer is similar to the variation of momentum transport. Overall features of the exchange processes are shown to be similar to those in simple two-dimensional, nonducted mixing flows if allowance is made for the three dimensionality of the present layers. However, it is also shown that there are significant quantitative differences between the two types of flow. The overall mass exchange rate between the two flow regions was found to be one-third of the mass rate supplied to the combustor and this is a typical figure for conventional designs.
Two-Phase Flow Through Normal Shock Wave
Authors: Narkis Y. , Gal-Or B.
Published: November 2010

The steady, one-dimensional flow of compressible gas containing particles through a normal shock wave is investigated. Following the derivation of a set of general equations, two extreme cases are treated, namely: 1 – Two-phase flow with high particle mass flow (so that their volume cannot be neglected) is first considered, and the final equilibrium conditions are analytically solved, whereas the relaxation zone is calculated numerically. The error in neglecting the particle volume is shown to be considerable in the calculation of the velocities. 2 – An approximate solution is secondly given for the case of low particle mass flow through a weak shock wave. Use is made here of small perturbations, for zeroth and first orders. The solution of this case describes the flow in the relaxation zone quite accurately, and shows its dependence on the physical properties of both gas and droplets.
Two-Dimensional Method for Calculating Separated Flow in a Centrifugal Impeller
Authors: Sturge D. P. , Cumpsty N. A.
Published: November 2010

A method of calculating a two-dimensional incompressible and inviscid flow within a centrifugal impeller where the flow separates from the suction side has been developed. Based on experimental observation it has been assumed that mixing of the throughflow with the separated region is suppressed. After a description of the calculation method, which is rather unusual, some results are presented and the implications discussed. The possibility of extending the method to handle compressible flow is outlined.
Pulsatile Blood Flow in a Channel of Small Exponential Divergence—Part II: Steady Streaming Due to the Interaction of Viscous Effects With Convected Inertia
Authors: Schneck D. J. , Walburn F. J.
Published: November 2010

This paper describes a secondary streaming motion that appears during the pulsatile flow of a viscous, incompressible fluid through rigid circular channels having walls which diverge at a slow exponential rate. Arising primarily from the interaction of viscous effects with convected inertial effects, this steady streaming motion acts to continuously retard downstream flow near the wall surface and enhance such flow nearer midstream. The secondary flow phenomenon is shown to be directly proportional to mean Reynolds Number, inversely proportional to the unsteadiness parameter of the flow, and to attenuate with decreasing rates of channel divergence. These effects are all self-consistent and interdependent.
Deceleration Rate Parameter and Algebraic Prediction of Turbulent Boundary Layer
Authors: Senoo Y. , Nishi M.
Published: November 2010

The deceleration rate θ1/λ, which is defined as the ratio of the momentum thickness to the distance where the free-stream velocity is reduced by 10 percent, is shown as an important and handy parameter to describe the development of turbulent boundary layer in an adverse pressure gradient. Using this parameter a simple calculation procedure of turbulent boundary layer is presented. In order to achieve a large inlet/exit velocity ratio, θ1/λ =0.02 may be recommended, where the influence of wall friction on the development of momentum loss is very small and the shape factor of boundary layer does not increase rapidly.
Effect of Upstream Flow Processes on Hydrodynamic Development in a Duct
Authors: Sparrow E. M. , Anderson C. E.
Published: November 2010

Consideration is given to the developing laminar flow in a parallel plate channel, with the fluid being drawn from a large upstream space. The flow fields upstream and downstream of the channel inlet were solved simultaneously. A finite-difference technique was employed which was facilitated by a coordinate transformation that telescoped the broadly extended flow domain into a more compact size. For the solutions, the Reynolds number was assigned values from 1 to 1000, covering the range from viscous-dominated flows to those where both viscous and inertia effects are relevant. Streamline maps indicate that whereas a low Reynolds number flow glides smoothly into the channel, a high Reynolds number flow has to turn sharply to enter the channel, with the result that the sharply turning fluid tends to overshoot at first and then readjust. A significant amount of upstream predevelopment occurs at low and intermediate Reynolds numbers. Thus, for example, at Re = 1 and 100, the center-line velocities at inlet are, respectively, 1.37 and 1.13 times the mean velocity (the fully developed center-line velocity is 1.5 times the mean). The upstream pressure drop, measured in terms of the velocity head, is substantially increased by viscous effects at low and intermediate Reynolds numbers.
Lateral Motion of Individual Particles in Channel Flow—Effect of Diffusion and Interaction Forces
Authors: Kondic´ Nenad N.
Published: November 2010

Consideration is given to dispersed systems in which the particle behavior is a function of systematic motion. The following phenomena governing the movement of the particles are analyzed from the channel entrance: convective effects, translation due to gravity, fluid drag, and circulation induced by the flow. External lateral forces and mutual particle interactions are not considered. Results are obtained for the magnitude and overall effects of the lateral force due to circulation around the particles. The analysis is closely related to the author’s measurements of the deposition of micron-size water droplets in adiabatic vertical flow.
Effect of Bubble Stabilization on Pool Boiling Heat Transfer
Authors: Fuls G. M. , Geiger G. E.
Published: November 2010

It is an established phenomenon that bubbles can be stabilized in a vertically vibrating liquid column. The effect of bubble stabilization on the rate of pool boiling heat transfer is experimentally investigated. With the liquid and heating surface vibrating as a unit, the data indicates a decrease of up to 12 percent in the temperature difference necessary for a given heat flux within the range of frequencies from 200 to 300 cps. The experimental results and comparison with results of previous investigators show that the effect is unique and not due simply to the vibrations per se.
Film Boiling on Horizontal Cylinders in Helium II
Authors: Holdredge R. M. , McFadden P. W.
Published: November 2010

The analysis of Rivers and McFadden for film boiling heat transfer from horizontal cylinders immersed in Helium II is briefly reviewed and results are recapitulated. Experimental measurements of film boiling heat transfer are made for horizontal cylinders of 0.145 cm and 0.245 cm dia immersed in Helium II baths at 1.78, 1.96, and 2.1 K at wall heat fluxes up to 2.84 w/cm2. The nondimensionalized experimental results are compared with the accepted correlations of Bromley and Breen and West-water to demonstrate the inability of the usual film boiling correlations to predict film boiling in Helium II. The nondimensionalized experimental results are compared with the predictions of the Rivers and McFadden analysis which considers Helium II properties, and the results of the analysis are substantiated.
The Effect of Finite Metal Conductivity on the Condensation Heat Transfer to Falling Water Rivulets on Vertical Heat-Transfer Surfaces
Authors: Brown Clinton E. , Matin Shaikh A.
Published: November 2010

An analytical study has been made of the condensation of vapor onto falling rivulets of liquid which are constrained in lateral width by vertical non-wetting Teflon stripes on a flat metal heat-transfer surface. Under the condition studied it is shown that finite metal conduction plays a primary role in limiting the overall heat-transfer coefficient because in any system (drops or rivulets) where a triple point of metal, vapor, and liquid exists, the zero water path at the triple point would provide an unlimited conductance of heat were it not for finite metal conductivity or interfacial resistance. In the present paper, the temperature field and heat flow in a liquid rivulet and the underlying metal are computed using finite-difference methods. The metal plate is of constant thickness but the liquid rivulet is bounded by an arc of a circle as dictated by surface tension. The system involves two connected regions of different conductivity and shape, and the entire network is solved by an over-relaxation process taking into account the discontinuity in temperature gradient at the liquid-metal junction. Results are related to the practical application of such a system in desalination processes. The work was supported by the Office of Saline Water, Department of the Interior.
Radiative Transfer Between Surfaces in a Cavity With Collimated Incident Radiation: A Comparison of Analysis and Experiment
Authors: Howell J. R. , Durkee R. E.
Published: November 2010

Analysts and experiment are compared for the radiant exchange among three surfaces making up an infinitely long cavity. Two of the cavity surfaces are specular-diffuse, while the third is bi directional. The cavity is exposed to collimated incident energy to maximize the effect of the surface reflectivity characteristics on the radiation exchange.
An Analysis of Combined Free and Forced Convection Heat Transfer From a Horizontal Circular Cylinder to a Transverse Flow
Authors: Joshi N. D. , Sukhatme S. P.
Published: November 2010

Combined free and forced convection heat transfer from a horizontal circular cylinder to a transverse flow is analysed for the case when the forced flow is either in the direction of the free convection flow (parallel flow) or in the direction opposite to it (counter flow). The problem is solved for two cases: (1) a specified surface temperature variation and (2) a specified wall heat flux variation along the circumference. A coordinate perturbation method is used to transform the governing set of partial differential equations into a system of ordinary differential equations, which are solved by numerical methods. The numerical work is done for the boundary conditions of constant surface temperature and constant wall heat flux. The variation of local heat transfer coefficient and wall shear stress along the circumference up to the point of separation and velocity and temperature profiles in the boundary layer are obtained for varying values of the governing parameters Gr/Re2 in the constant temperature case (or Gr/Re2 in the constant heat flux case) and Pr.
Optimum Plate Spacings for Laminar Natural Convection Heat Transfer From Parallel Vertical Isothermal Flat Plates
Authors: Levy E. K.
Published: November 2010

The problem of determining the optimum spacings between parallel vertical isothermal flat plates which are dissipating heat by natural convection to the environment is discussed. One optimum, first suggested by experimental data of Elenbaas with air and later derived theoretically by Bodoia, corresponds to the spacing between parallel vertical plates attached to a surface which will permit the maximum rate of heat transfer from that surface. A different optimum is derived in this paper which for a given heat flux gives the minimum plate spacing required to minimize the temperature difference between the plates and the fluid. The minimum temperature difference is shown to occur when the plate spacing is made sufficiently large that the wall boundary layers do not merge. It is shown that Elenbaas’ optimum, although requiring a plate spacing only 54 percent of that for minimum ΔT, produces a temperature difference which is 38 percent higher than the minimum.
Thermal Radiation from a Microscopically Roughened Dielectric Surface
Authors: Caren R. P. , Liu C. K.
Published: November 2010

The emission of thermal radiation from a microscopically roughened dielectric surface is treated using a laminar-inhomogeneous layered model for a representation of the effective spatial variation in refractive index associated with a roughened surface layer. The Riccati equation is used to calculate the modification to the spectral angular transmittance of the surface due to the presence of this inhomogeneous surface layer. A consideration of the emission of radiant energy from the bulk dielectric through the surface layer permits the angular emittance to be determined. Total emittance values are obtained using the spectral angular emittance data.
Theoretical Distributions of Heat Transfer Downstream of a Backstep in Supersonic Turbulent Flow
Authors: Lamb J. P. , Hood C. G.
Published: November 2010

A physically perceptive model is presented for the flow field and convective transport processes in the vicinity of reattachment of a planar, supersonic, turbulent flow. Control volume methods are utilized extensively in the analysis and the restating integral equations are solved by various numerical search techniques. The analysis enables one to determine significant parameters in the flow field as well as the heat transfer distribution and associated wall temperature of the reattachment surface. Also presented is a general correlation of predicted results for the convection process in terms of pertinent independent variables. The correlated results are shown to agree with measurements for a wide range of test conditions.
Transient Film Boiling of Carbon Tetrachloride and Freon-113 on a Horizontal Cylindrical Surface
Authors: Wehmeyer D. P. , Jackson T. W.
Published: November 2010

This paper presents an experimental and analytical investigation to determine the film growth during the initial regimes of transient film boiling from a horizontal wire for carbon tetrachloride and Freon-113. The wire was subjected to a step change in temperature by a rapid discharge of energy from an electrical capacitor. Constant wire temperature was assumed in the analytical model, and heat transfer through the vapor phase was assumed to be by radiation and conduction. All radiation from the wire was determined to pass through the vapor and to be absorbed in depth within the liquid phase. Convection heat transfer to the liquid pool was considered to take place at the vapor–liquid interface. Heat-transfer rates within the vapor phase were calculated, as was the growth rate of the vapor–liquid interface.
On the Delayed Hot Water Problem
Authors: Comstock C. , Zargary A. , Brock J. E.
Published: November 2010

A pipe with external insulation contains a flowing fluid at constant temperature. Suddenly there is a jump in inlet fluid temperature. The subsequent temperature distribution in the fluid and in the pipe is studied by means of perturbation expansions, one of which is singular. Simplifying assumptions are explicitly stated. Some extensions and unifications of previous work are found.
Heat Transfer and Film Cooling Following Injection Through Inclined Circular Tubes
Authors: Eriksen V. L. , Goldstein R. J.
Published: November 2010

Film cooling effectiveness and heat transfer are measured downstream of injection through discrete holes into a turbulent mainstream boundary layer. Air is injected through both a single hole and a row of holes spaced at three-diameter intervals and inclined at an angle of 35 deg to the main flow. There is little difference between the heat transfer coefficient with blowing and without blowing at low blowing rates (mass flux ratios). In fact, at low blowing rates, injection is found to decrease somewhat the heat transfer coefficient from that measured without blowing. As the mass flux ratio increases past unity, the heat transfer coefficient increases especially with injection through a row of holes. The peak heat transfer is usually found at the edge of the spreading jets (i.e., between two holes). At a blowing rate near two, the lateral average of the heat transfer is as much as 27 percent higher than the heat transfer with no blowing. The increase in heat transfer is attributed to the interaction between the jets and the free stream, causing high levels of turbulence.
An Experimental Investigation of a Heated Two-Dimensional Water Jet Discharge Into a Moving Stream
Authors: Patton A. J. , Test F. L. , Hagist W. M.
Published: November 2010

The experimental results are presented for a study of the behavior of heated and unheated two-dimensional water jets injected from the bottom of a moving water stream. The jet characteristics are described in terms of velocity and temperature profiles, velocity and temperature decay, jet width, jet trajectory, and jet turbulence. The conditions which favor the formation of an upstream thermal wedge are investigated.
Experimental Study of Turbulent Flow in a Tube With Wall Suction
Authors: Brosh A. , Winograd Y.
Published: November 2010

The effect of wall suction on the turbulent flow of air in a porous tube has been studied. Measurements of the radial distribution of the turbulent velocity fluctuations were obtained over a range of Reynolds numbers from 104 to 2 × 105. Various suction rates were employed, for both local suction over a short length of tube and continuous suction over various lengths. The results obtained for local suction (step reduction in Reynolds number) show that approximately 40 dia are required for the turbulent velocity fluctuations to reach flow equilibrium at the lower downstream value of the Reynolds number. The results for the case of continuous suction show that after a short suction length, there is an apparent increase in the turbulence level compared with that found at the same Reynolds number with no suction. This appears to be due to the greater turbulence level which exists at the higher (presuction) Reynolds number. Longer suction lengths, above 40 dia, always result in a decrease in the turbulence level compared with turbulent flow with no suction at the same Reynolds number. The present results suggest that simple mixing-length models, incorporating local flow parameters, may be inadequate to describe the turbulent momentum transport in a tube with surface suction. Certainly, the existing mixing-length models should be re-examined in the light of this new experimental data.
Quasi-Steady Laminar Film Condensation of Steam on Copper Spheres
Authors: Dhir V. K.
Published: November 2010

An experimental study of laminar film condensation of steam on copper spheres of 1.90, 2.54, and 3.17 cm dia has been made. Experiments have been performed by submerging cold spheres in nearly stagnant water vapor at a saturation temperature of about 99° C. Values of Nusselt number based on average heat transfer coefficient are obtained for saturation to wall temperature differences of 5–65° C and for cp ΔT/hfg in the range of 0.009–0.12. The data are compared with the steady-state predictions of Dhir and Lien-hard and of Yang. Analysis has been made to show that it is valid to use steady-state solutions in quasi-steady condensation as long as the dimensionless thermal diffusion time constant is small, and the film does not move very slowly.
Shock Tube Measurements of the Emission of Carbon Dioxide in the 2.7 Micron Region
Authors: Hsieh T. C. , Hashemi A. , Greif R.
Published: November 2010

Measurements have been made of the infrared emission of carbon dioxide in the 2.7 micron region. The measurements were carried out in a free piston shock tube at temperatures of 2400 and 3500° K. Results are reported for the mean line intensity to spacing ratio and for the emissivity.
Threshold Lesion Temperatures in Argon Laser-Irradiated Rabbit Eyes
Authors: Polhamus G. D. , Welch A. J.
Published: November 2010

The purpose of this research was to measure threshold temperatures corresponding to the formation of minimum ophthalmoscopically visible lesions induced in rabbit ocular fundi by a 10-s exposure from an argon c. w. laser (4880 Å). The backside of the eye was surgically exposed and a specially designed microthermocouple with a 20-micron dia tip was inserted into the pigment epithelium to measure temperature rises. The mean threshold temperature for 30 measurements in 13 rabbits was 54° C and the standard deviation was 3° C. System error was estimated at 5 percent of temperature rise, or slightly less than ±1/2° C.
Mean Temperature Profiles in Heated Laminarizing Air Flows
Authors: Perkins K. R. , McEligot D. M.
Published: November 2010

Experiments for air flowing upward in a vertical circular tube are presented for heating rates causing significant property variation. Entering Reynolds numbers vary from 3800 to 8500 with the dimensionless heating parameter, qw″/(Gcp, iTi), varying from 0.001 to 0.0055. Data include the first developing internal profiles for the apparent reverse transition from turbulent to laminar flow due to heating. Emphasis is placed on internal temperature distributions, t(x, r), taken at axial stations from about 3–25 dia after the start of heating. The flow regimes range from nearly constant property, turbulent flow to strongly heated laminarizing flow. Results for strongly heated flows show a definite increase in the thickness of both the linear sublayer and the viscous sublayer. For laminarized flow, the linear sublayer extends about half the distance to the cener line of the tube or more.
A Study of Transient Heat Transfer in Long Insulated Wires
Authors: Jaluria Y.
Published: November 2010

This study concerns the transient thermal response of long insulated wires, a composite cylinder configuration, in which a highly conducting inner cylinder is sheathed in an outer cylinder of an insulating material. The study examines the heat transfer in such a cylindrical configuration and determines the parameters that govern its thermal response. A study of the transient behavior under various important surface boundary conditions, particularly the constant surface heat flux circumstance, is undertaken. The dependence of the transient response of the body, in terms of the characteristic surface and conductor temperatures, of the temperature distribution across the insulation and of other important physical aspects on the boundary conditions and on the governing parameters is investigated. The governing equation and boundary conditions are generalized and the solution obtained numerically to obtain the desired flexibility required for the variation in the boundary conditions. Several important and interesting results are obtained which indicate the nature of the thermal response and also the criteria for obtaining a desired variation in the transient behavior of this frequently encountered configuration.
Asymptotic Analysis of the Average, Steady, Isothermal Flow in Coupled, Parallel Channels
Authors: Lund K. O.
Published: November 2010

The conservation equations of mass and momentum are derived for the average flow of gases in coupled, parallel channels, or rod bundles. In the case of gas-cooled rod bundles the pitch of the rods is relatively large so the flows in the channels are strongly coupled. From this observation a perturbation parameter, ε, is derived and the descriptive equations are scaled using this parameter, which represents the ratio of the axial flow area to the transverse flow area, and which is of the order of 10−3 in current gas-cooled fast breeder reactor designs. By expanding the velocities into perturbation series in ε the equations for two channels are solved as an initial value problem, and the results compared to a finite difference solution of the same problem. Then, the N-channel, problem is solved to the lowest order as a two-point boundary value problem with the pressures specified at the inlet and the outlet. It is concluded from the study that asymptotic methods are effective in solving the flow problems of rod bundles; however, further work is required to evaluate the possible computational advantages of the methods.
A Surface Rejuvenation Model for Turbulent Heat Transfer in Annular Flow With High Prandtl Numbers
Authors: Chung B. T. F. , Thomas L. C. , Pang Y.
Published: November 2010

Heat transfer for high Prandtl number fluids flowing turbulently in a concentric circular tube annulus with prescribed wall heat flux is investigated analytically. This surface rejuvenation based analysis is restricted to thermally and hydrodynamically fully developed flow with constant properties and negligible viscous dissipation. This formulation leads to predictions for the Nusselt Number that are in basic agreement with predictions obtained on the basis of earlier eddy diffusivity models for 30 ≤ Pr ≤ 1000 and 104 ≤ Re ≤ 106.
An Asymptotic, Thermo-Diffusive Ignition Theory of Porous Solid Fuels
Authors: Kim Choong Se , Chung Paul M.
Published: November 2010

The governing equations of thermal ignition are analyzed for porous solid fuel, such as coal, of various two-dimensional and axisymmetric geometries by the Laplace asymptotic method. Mass diffusion of the gaseous oxidant through the porous fuel is included. The nonlinear partial differential equations of energy and mass balances in time-space coordinates containing the Arrhenius volumic chemical reaction terms are analyzed. By employing the Laplace asymptotic technique and by invoking a certain limit theorem, the governing equations are reduced to a first order ordinary differential equation governing the fuel surface temperature, which is readily solved numerically. Detailed discussion of the effects of the various governing parameters on ignition is presented. Because of the basically closed-form nature of the solutions obtained, many general and fundamental aspects of the ignition criteria hitherto unknown are found.
The Calculation of Furnace-Flow Properties and Their Experimental Verification
Authors: Hutchinson P. , Khalil E. E. , Whitelaw J. H. , Wigley G.
Published: November 2010

Measurements of mean axial velocity, and the corresponding normal stress are reported for the isothermal flow of air and for a combusting mixture of natural gas in an axisymmetric furnace enclosure with a coaxial burner. Temperature and wall heat flux measurements were also obtained for the combusting flow. The swirl number of the flow was 0.5. The measurements are compared with the results of a calculation procedure incorporating a two equation turbulence model and a one step reaction model. The combustion model allowed fuel and oxygen to coexist at the same place but not at the same time. The comparison indicates that the calculation procedure qualitatively represents the measurements but that quantitative differences exist. The argument is sufficiently close, however, to justify the use of the method for some design purposes.
Error in Temperature Measurements Due to Conduction Along the Sensor Leads
Authors: Singh B. S. , Dybbs A.
Published: November 2010

When a sensor is embedded in a solid body to measure its internal temperature, any conduction to, or from, its sensing element may cause the indicated temperature to be different from the true temperature. This paper describes an analysis of the error caused by conduction when there is an arbitrary temperature distribution in thebbody along the sensor. The sensor is modeled as a cylindrical fin and the appropriate conduction equation is solved. The solution gives a correction for the error which depends on such parameters as, depth of immersion, thermocouple wire and insulation properties, contact between the sensor and the body, and temperature distribution in the body. The latter may not be known, but the measured temperature distribution can be used as a first approximation. The corrected value can then be used to obtain a better estimate of the error. The results show good agreement with experimental observations.
An Experimental Investigation of Heat Transfer Around A Tube in A Bank
Authors: Aiba S. , Yamazaki Y.
Published: November 2010

An experimental investigation of heat transfer and flow around the second cylinder of three cylinders in cross flow of air was conducted. The cylinders were situated in tandem at equal distances between centers. Their in-line pitch ratio was in the range 1.3 ≦ c/d ≦ 5.0 (c = center-to-center distance; d = diameter); the Reynolds number was 40000. Heat transfer results indicate a strong dependence on the difference between the maximum static pressure on the surface and the static pressure at the front stagnation point of the second cylinder. The maximum local heat transfer around the second cylinder occurs at the position where the free vortex layer (free shear layer) shed from the first cylinder attaches. However, the turbulence intensity near the wall at this same position is lower than that at other angular positions.
Heat Transfer Between a Moving Surface and a Flowing Medium
Authors: Bott T. R. , Law D. V.
Published: November 2010

Certain processes involve heat transfer across a moving surface and application of the well-known “penetration theory” to scraped-surface heat transfer, suggests that this theory might be applied to this situation. At high water flows and high surface speeds experimental results agree well with the theory, but at lower values the experimental heat-transfer rates are much higher than those predicted from the theory, and at high surface speeds and lower water velocities the experimental value of the heat transfer coefficient is lower than predicted. The differences are attributed to additional turbulence and secondary-flow (back-mixing) effects, which would be extremely difficult to allow for in the theory.
Thermal Traces of a Buried Heat Source
Authors: Small R. D. , Weihs D.
Published: November 2010

An exact solution in series form is presented for the steady temperature distribution in a semi-infinite solid medium bounded internally by a spherical inclusion of uniform temperature. Heat transfer at the interface is via convection. The solution is obtained by means of a transformation to a bispherical coordinate system. Surface temperatures, which are of engineering interest for monitoring purposes, are also calculated.
Free Convection Heat Transfer Across Inclined Honeycomb Panels
Authors: Cane R. L. D. , Hollands K. G. T. , Raithby G. D. , Unny T. E.
Published: November 2010

Experimentally obtained Nusselt number-Rayleigh number plots are presented for free convective heat transfer across honeycomb panels, heated from below, and inclined with respect to the horizontal at angles of 0, 30, 45, 60, and 90 deg. Aspect ratios of honeycomb cells of 2, 3, 4, and 5 are included; the fluid contained in the cells is air. Substantial suppression of free convection is observed when compared with an air layer of the same depth but not containing a honeycomb. Heat transfer associated with the base flow is found to be of only moderate importance at angles near horizontal, but of considerable consequence for angles near the vertical. The honeycomb walls used were partly transparent to thermal radiation, and a strong radiative coupling is indicated. A correlation equation for the Nusselt number, valid over part of the experimental range, is presented.
Heat Transfer Controlled Collapse of a Cylindrical Vapor Bubble in a Vertical Isothermal Tube
Authors: Pitts D. R. , Hewitt H. C. , McCullough B. R.
Published: November 2010

An experimental program was conducted to determine the collapse rate of slug-type vapor bubbles rising due to buoyancy through subcooled parent liquid in a vertical isothermal tube. The experimental apparatus included a vertical glass tube with an outer glass container providing a constant temperature water bath for the inner tube. The inner tube contained distilled, deaerated water, and water vapor bubbles were generated at the bottom of this tube with a pulsed electric heater. The parent liquid was uniformly subcooled with respect to the vapor bubble resulting in heat transfer controlled bubble collapse. Collapse rates and rise velocities were recorded by high-speed motion picture photography. Over a limited range of subcooling, the bubble collapse was well behaved, and a simple, quasi-steady boundary layer heat transfer analysis adapted from slug flow over a flat plate correlated the experimental results with a high degree of accuracy. Experimental results were obtained with tubes having inside diameters of 0.0127, 0.0218, and 0.0381 m and for a range of subcooling from 0.5 to 9.0 K.
Heat Transfer From a Cylinder in Crossflow Situated in a Turbulent Pipe Flow
Authors: Pederson R. J. , Sparrow E. M.
Published: November 2010

Experiments to measure the average heat transfer characteristics for a cross-flow cylinder situated in a pipe flow have been performed for various degrees of blackage. Three cylinders, respectively with diameters of one-fifth, one-third, and one-half that of the pipe, were employed. The experiments were carried out with both water and air as working fluids. Measurements were also made of the turbulence level in the flow approaching the cylinder. The measured heat transfer results were compared with literature information for a cylinder of large length-diameter ratio situated in cross-flow in an unbounded low-turbulence flow (i.e., the ideal case of a cylinder in cross-flow) and were found to be substantially higher. A number of schemes were investigated for correlating the cylinder-in-pipe results with those for the ideal case. As an outcome of these correlation efforts, adaptations of available ideal cylinder relations are presented from which cylinder-in-pipe results can be predicted with good accuracy.
Natural Convection In Compound Parabolic Concentrators—A Finite-Element Solution
Authors: Abdel-Khalik S. I. , Li H.-W. , Randall K. R.
Published: November 2010

Natural convection heat transfer coefficients between absorber surfaces and cover plates for vertically oriented two-dimensional compound parabolic concentrators (CPC) are evaluated using finite-element techniques. Values of the critical Rayleigh number for different concentrations (2 < C < 10) with 1/3, 2/3, and full CPC heights are determined. Generalized charts for estimating the average absorber plate Nusselt number as a function of Rayleigh number and concentration for both full and truncated CPC cavities are given. The results are useful for evaluating the covective loss coefficients from such collectors.
Analytic Solutions to the Heat Equation Involving a Moving Boundary with Applications to the Change of Phase Problem (the Inverse Stefan Problem)
Authors: Rubinsky Boris , Shitzer Avraham
Published: November 2010

Long time analytic solutions to the inverse Stefan problem are presented in Cartesian and spherical coordinates. This problem deals with the phase change of a substance with the boundary conditions specified at the moving boundary. The solutions, expressed in infinite series, facilitate the calculation of temperature and heat flux variations in the phase changing medium and at the interface with the heat source element. Applications of the present analysis are in aerospace engineering, e.g., controlled ablation of thermal shields; metallurgy, e.g., controlled casting; bioengineering, e.g., cryopreservation of tissues, and numerous applications in which a controlled change of phase of a substance is involved.
Simultaneous Measurements of Velocity and Temperature in Nonisothermal Flows
Authors: Hishida M. , Nagano Y.
Published: November 2010

A two-wire probe technique has been developed for the simultaneous and continuous measurements of instantaneous velocity and temperature in nonisothermal flows. The equations of the thermal equilibrium of two adjacent fine wires, one hot and one only a little above the fluid temperature, are solved by employing analog technique, wherein not only the difference of the heat transfer coefficients between two wires but also their variations with both the velocity and temperature are taken into consideration. The measuring system proposed in this study is founded on fairly strict principles of analysis and, hence, provides automatic compensation even for very large amplitude velocity and temperature fluctuations over a frequency range of d-c to six kHz.
Partial Spectral Expansions for Problems in Thermal Convection
Authors: Shaughnessy E. J. , Custer J. , Douglass R. W.
Published: November 2010

The use of spectral expansions for solving nonlinear partial differential equations is explained, and two examples drawn from convective heat transfer are presented. For both problems the results agree well with regular perturbation solutions at parameter values for which the latter remain valid. Evidence is given to indicate that the spectral solutions are valid for considerably larger parameter values than can be reached with the perturbation methods.
Magnetic Field Effects on Bubble Growth in Boiling Liquid Metals
Authors: Wong C. P. C. , Vliet G. C. , Schmidt P. S.
Published: November 2010

A theoretical analysis of bubble growth in superheated liquid metals shows that in the presence of a strong magnetic field, the growing bubble would assume an elongated shape and the volume would be less than that for the nonmagnetic case. As time progresses and for higher field strengths the bubble becomes more elongated. The analytical results are used to estimate the effect of strong magnetic fields on nucleate boiling heat transfer.
Two-Dimensional Multiple Scattering: Comparison of Theory with Experiment
Authors: Look D. C. , Nelson H. F. , Crosbie A. L. , Dougherty R. L.
Published: November 2010

Theoretical and experimental multiple scattering results are compared for a two-dimensional geometry. The two-dimensional model predicts the radial distribution of the radiation leaving a semi-infinite isotropically scattering cylindrical medium exposed to colli-mated radiation. The results show that the intensity leaving the media can be expressed as a universal function of the optical radius. The experimental results are obtained using a He–Ne laser beam incident normal to the surface of a tank of distilled water which contains scattering centers (latex paint). The agreement between theory and experiment is good.
On the Mechanism of Liquid Drop Deposition in Two-Phase Dispersed Flow
Authors: Ganic´ E. N. , Rohsenow W. M.
Published: November 2010

The deposition motion of liquid drops (the migration of drops toward the wall) in dispersed flow heat transfer is analyzed. Equations of drop motion penetrating the laminar sublayer are derived taking into account inertia forces arising from change in the velocity of drop, drag forces, buoyancy forces, gravity forces, lift forces (forces due to rotation of the drop inside laminar sublayer caused by high vapor velocity gradient) and reaction forces due to asymmetrical drop evaporation inside laminar sublayer. A new expression for the reaction force is derived. The application of the developed drop deposition model is illustrated by calculating several quantities of practical interest for analysis of heat and mass transfer in dispersed systems. Also, the model has been applied to explain the behavior of the dispersed flow boiling heat transfer data.
Rating Life of a Linear Motion Assembly
Authors: Hyer J. P. , Harris T. A.
Published: November 2010

The linear motion assembly is a type of rolling bearing used to support and guide a translating member along a round shaftway. The load-carrying adequacy of this bearing for a given application is evaluated in the same way as for conventional rolling bearings by determining a statistical fatigue life. This paper presents an analytical development of the equations for dynamic capacity from which fatigue life can be calculated. Contact deflection and the effects of preload are also examined.
The Effect of Fluid Inertia on a Porous Thrust Plate—An Analytical Solution
Authors: Hsing F. C.
Published: November 2010

A theoretical analysis was made to study the effect of fluid inertia on a porous thrust plate. The most elementary configuration was chosen as an analytic model to investigate this effect with a minimum of mathematical complexities. Numerical data were obtained for an incompressible film. The results reveal that the effect of fluid inertia can be important, depending on the film thickness H and a parameter Ω. For small value of H the inertia effect is essentially confined to a very narrow region near the edge of the bearing while for large values of H this effect spreads throughout the fluid film. This pressure boundary layer at low H is similar to that in a self-acting gas bearing. In general it was found that inertia effects tend to influence favorably the flow and load capacity of porous thrust plates.
Inhibition of Water-Accelerated Rolling-Contact Fatigue
Authors: Schatzberg Paul
Published: November 2010

Water in lubricating oils causes a significant reduction in rolling-contact fatigue life. This effect can be inhibited by lubricant additives that interfere with the mechanism by which water reduces fatigue life. Using a planetary four-ball machine, it is demonstrated that the addition of 0.1 percent isopropylaminoethanol completely counteracts the detrimental influence due to 1 percent seawater emulsified with the lubricant. It is suggested that the aminoalcohol condenses into surface microcracks along with water, captures hydrogen ions formed within the crack and thereby inhibits hydrogen embrittlement.
Operating Experience With Filled P.T.F.E. Piston Rings
Authors: Summers-Smith D.
Published: November 2010

This paper gives details of the lives of 188 sets of filled P.T.F.E. piston rings in a variety of reciprocating compressors covering a wide range of operating conditions. Although satisfactory performance has been obtained in most cases, there has been a considerable experience of inconsistent behavior. This had led to the adoption of certain standardized practices based on the experience obtained so far in an attempt to increase the consistency of performance. In particular, these cover ring formulations and design, and the avoidance of trace quantities of lubricant.
Labyrinth Seal Analysis
Authors: Koenig H. A. , Bowley W. W.
Published: November 2010

A computer code is developed herein which is shown to be a useful tool in the design of labyrinth seals for gas turbine and other engineering applications. The algorithm is based upon theoretical considerations and is general enough to provide seal design parameters for a variety of input and flow conditions. Two examples are solved. The first, a theoretical consideration, demonstrates the ability of the program to effectively treat various geometrical and dynamic conditions. The second, an actual test, demonstrates the accuracy with which the analysis will predict the actual seal leakage behavior.
Experimental Rotor Unbalance Response Using Hydrodynamic Gas Lubrication
Authors: Dayton R. D. , Chasman M. R.
Published: November 2010

This paper investigates the adequacy of the theoretical model in predicting the unbalance response of a rotor supported in hydrodynamic gas lubricated journal bearings. The magnitude of experimental whirl amplitudes induced by applying various unbalances to a rotor supported in hydrodynamic journal bearings were measured and compared to the theoretical predictions. Variables investigated were rotor unbalance, rotor speed, and bearing load. Reasonable agreement between the experimental and theoretical results was obtained.