Journal ArticleDOI
Comparison of Turbulent Heat-Transfer Results for Uniform Wall Heat Flux and Uniform Wall Temperature
Robert Siegel,Ephraim M Sparrow +1 more
TLDR
In this article, the Nusselt numbers for turbulent heat transfer in both the fully developed and thermal entrance regions of a circular tube are affected by two different wall boundary conditions.Abstract:
The purpose of this note is to examine in a more precise way how the Nusselt numbers for turbulent heat transfer in both the fully developed and thermal entrance regions of a circular tube are affected by two different wall boundary conditions. The comparisons are made for: (a) Uniform wall temperature (UWT); and (b) uniform wall heat flux (UHF). Several papers which have been concerned with the turbulent thermal entrance region problem are given. 1 Although these analyses have all utilized an eigenvalue formulation for the thermal entrance region there were differences in the choices of eddy diffusivity expressions, velocity distributions, and methods for carrying out the numerical solutions. These differences were also found in the fully developed analyses. Hence when making a comparison of the analytical results for uniform wall temperature and uniform wall heat flux, it was not known if differences in the Nusselt numbers could be wholly attributed to the difference in wall boundary conditions, since all the analytical results were not obtained in a consistent way. To have results which could be directly compared, computations were carried out for the uniform wall temperature case, using the same eddy diffusivity, velocity distribution, and digital computer program employed for uniform wall heat flux. In addition, the previous work was extended to a lower Reynolds number range so that comparisons could be made over a wide range of both Reynolds and Prandtl numbers.read more
Citations
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Journal ArticleDOI
Heat and mass transfer laws for fully turbulent wall flows
B.A Kader,A.M. Yaglom +1 more
TL;DR: In this article, the Nusselt number was used for the analysis of turbulent heat and mass transfer in pipes, channels, and boundary layers, where the dimensionless coefficients of the universal logarithmic equations for the velocity and temperature profiles were derived.
Journal ArticleDOI
Heat and mass transfer between a rough wall and turbulent fluid flow at high Reynolds and Péclet numbers
A. M. Yaglom,B. A. Kader +1 more
TL;DR: In this article, the authors derived a heat and mass transfer law for fully turbulent flow along a rough wall, which is quite analogous to Millikan's (1939) derivation of a skin-friction law for smooth-and rough-wall flows.
Journal ArticleDOI
Design procedure for cooling ducts to minimise efficiency loss due to temperature rise in PV arrays
B. J. Brinkworth,Mats Sandberg +1 more
TL;DR: In this paper, the principal variable to be fixed in the design of a PV cooling duct is its depth, and hence the hydraulic diameter of its cross-section D. It is shown that there is an optimum value of this design variable, such that for an array of length L the minimum temperature occurs when the ratio L/D is about 20.
Journal ArticleDOI
The effect of axially varying and unsymmetrical boundary conditions on heat transfer with turbulent flow between parallel plates
A.P. Hatton,Alan Quarmby +1 more
TL;DR: In this paper, a solution to the heat-transfer problem with turbulent flow between parallel plates with heating on one side only is presented, and the eigenvalues and functions necessary to calculate the variation of Nusselt number with distance along the passages are tabulated for three Reynolds and three Prandtl numbers.
Journal ArticleDOI
Review: Convective heat and mass exchange predictions at leaf surfaces: Applications, methods and perspectives
TL;DR: In this article, an overview is given on the different methods to obtain convective transfer predictions, namely analytical, experimental and numerical methods, and their restrictions and current knowledge gaps are identified.
References
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Journal ArticleDOI
Turbulent heat transfer in the thermal entrance region of a pipe with uniform heat flux
TL;DR: In this article, a thermal entry length is defined as the heated length required to bring the local Nusselt number to within 5 percent of the fully developed value of the fluid.
Journal ArticleDOI
Heat transfer in turbulent tube flow
TL;DR: In this paper, the temperature distribution in a laminar flow through a smooth cylindrical tube can be solved on certain assumptions by separating the variables; the result is a temperature distribution given by a linear combination of eigenfunctions.
Heat transfer in a pipe with turbulent flow and arbitrary wall-temperature distribution
TL;DR: The first three eigenvalues and constants for the problem of heat flow to a constant property fluid in established turbulent flow in a round pipe are presented for all important values of Reynolds and Prandtl Moduli as mentioned in this paper.
Book
Heat Transfer in a Turbulent Liquid or Gas Stream
TL;DR: In this paper, the authors developed systematically the theory of heat transfer and of the dependence of the unit thermal conductance upon shape and dimensions, using as a basis the velocity distribution for turbulent flow set up by Prandtl and Von Karman.
Related Papers (5)
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