Heat-transfer analysis and thermal dispersion in thermally-developing region of a sintered porous metal channel

Abstract The thermal dispersion and heat-transfer processes in the thermally-developing region of a sintered porous metal channel with asymmetric heating are analyzed by a two-equation model. The two-equation model considers different energy equations for the bronze and air due to the large difference in their thermal conductivities. In order to account for the large heat-transfer characteristics caused by the growth of thermal boundary layer in the thermal entrance region, the thermal dispersion conductivity is modeled as the product of an entrance-effect function, the dispersive length and the Peclet number. The empirical coefficients in the entrance-effect function are determined by comparing the experimental data. From the calculated results it is found a two-equation model underpredicts the Nusselt number if the thermal-entrance effect function is not included in the model. A parametric study is also conducted to investigate the effect of Peclet number and thermal conductivity ratio on the calculated Nusselt number distribution.

[1]  H. Zhu,et al.  Effects of radial thermal dispersion on fully-developed forced convection in cylindrical packed tubes , 1987 .

[2]  S. N. Upadhyay,et al.  ON THE LOW REYNOLDS NUMBER MASS TRANSFER IN PACKED BEDS , 1975 .

[3]  John F. Brady,et al.  The effective diffusivity of fibrous media , 1986 .

[4]  H. Johnstone,et al.  Heat and mass transfer in packed beds , 1955 .

[5]  A. Dybbs,et al.  Internal heat transfer coefficients of porous metals , 1982 .

[6]  K. Vafai,et al.  Effects of boundary conditions on non-Darcian heat transfer through porous media and experimental comparisons , 1995 .

[7]  S. Whitaker.  Forced convection heat transfer correlations for flow in pipes, past flat plates, single cylinders, single spheres, and for flow in packed beds and tube bundles , 1972 .

[8]  Kambiz Vafai,et al.  Analysis of dispersion effects and non-thermal equilibrium, non-Darcian, variable porosity incompressible flow through porous media , 1994 .

[9]  P. Cheng,et al.  Thermal dispersion in a porous medium , 1990 .

[10]  Sakae Yagi,et al.  Heat and mass transfer from wall to fluid in packed beds , 1959 .

[11]  P. Cheng,et al.  Forced Convection in the Entrance Region of a Packed Channel With Asymmetric Heating , 1988 .

[12]  D. Burfield,et al.  Vapor‐liquid equilibria and dielectric constants for the helium‐carbon dioxide system , 1970 .

[13]  J. Koh,et al.  Analysis of Cooling Effectiveness for Porous Material in a Coolant Passage , 1974 .

[14]  M. Yavuz Corapcioglu,et al.  Advances in transport phenomena in porous media , 1987 .

[15]  S. Bories.  Natural Convection in Porous Media , 1987 .

[16]  Chung-Hsing Chao,et al.  Heat Transfer Measurement and Analysis for Sintered Porous Channels , 1994 .

[17]  C. Tien,et al.  Effects of thermal dispersion on forced convection in fibrous media , 1988 .

[18]  P. Cheng,et al.  Applications of Van Driest's mixing length theory to transverse thermal dispersion in forced convective flow through a packed bed , 1986 .

[19]  Y. Chu,et al.  Heat transfer to air flowing through packed tubes , 1952 .