A boundary layer analysis of combined heat and mass transfer by natural convection from a concentrated source in a saturated porous medium

1996 ◽  
Vol 56 (1) ◽  
pp. 1-11 ◽  
Author(s):  
A. Nakayama ◽  
T. Ashizawa
1993 ◽  
Vol 115 (3) ◽  
pp. 606-612 ◽  
Author(s):  
R. L. Mahajan ◽  
D. Angirasa

A numerical study is presented for combined heat and mass transfer by natural convection from a vertical surface with opposing buoyancy effects. A comparison with similarity solutions shows that boundary layer analysis is suitable only when the two buoyant forces aid each other. For opposing flows the boundary layer analysis does not predict the transport rates accurately. A detailed comparison with experimental data with opposing buoyancies shows good agreement between the data and the numerical solutions. The heat and mass transfer rates follow complex trends depending on the buoyancy ratio and the Prandtl and Schmidt numbers. Comprehensive Nusselt and Sherwood number data are presented for a wide range of thermal Grashof number, buoyancy ratio, and Prandtl and Schmidt numbers.


2018 ◽  
Vol 16 ◽  
pp. 140-157 ◽  
Author(s):  
Nasreen Bano ◽  
Oluwole Daniel Makinde ◽  
B.B. Singh ◽  
Shoeb R. Sayyed

This paper deals with the study of the heat and mass transfer characteristics of natural convection from a horizontalsurface embedded in a radiating fluid saturated porous medium. Similarity solutions for buoyancy induced heat and masstransfer from a horizontal surface, where the wall temperature and concentration are a power function of distance fromthe origin, are obtained by using an integral approach of Von Karman type. The effects of the governing parameters suchas buoyancy ratio, Lewis number, radiation parameter and the power-law exponent on local Nusselt and local Sherwoodnumbers have been investigated both numerically and graphically.


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