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Evaporation of Non-Newtonian Fluid in Porous Medium Under Mixed Convection

Published online by Cambridge University Press:  05 May 2011

M.-H. Shih*
Affiliation:
Department of Mechanical Engineering, Chinese Military Academy, Fengshan, Taiwan 83059, R.O.C.
W.-J. Luo*
Affiliation:
Department of Refrigeration, Air-Conditioning and Energy Engineering, National Chin-Yi University of Technology, Taichung County, Taiwan 41101, R.O.C.
K.-C. Yu*
Affiliation:
Department of Refrigeration, Air-Conditioning and Energy Engineering, National Chin-Yi University of Technology, Taichung County, Taiwan 41101, R.O.C.
*
*Assistant Professor
*Assistant Professor
**Lecturer
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Abstract

This study investigates the problem of non-Newtonian liquid evaporation from an impermeable vertical plate in a porous medium under mixed convection conditions. The analysis examines the effects of non-Darcian flow phenomena on the evaporation process and investigates the heat and mass transfer characteristics under a range of flow conditions in the aiding and opposing flow types. The parameters of interest include Rak,non, Pex,non, Pr and Sc. The data required for the calculations include a fixed wall temperature of Tw = 45°C, a free flow temperature of T∞ = 20°C and an air free flow rate of u∞ = 4m/sec and the corresponding humidity of 50% flows over fixed temperature and moist wall.

The results indicate that an increasing buoyancy force enhances the mixing effect and therefore improves the rate of heat transfer, the latent heat flux is the primary mode of heat transfer in evaporation processes and the velocity gradient at the wall increases with an increasing buoyancy effect. Furthermore, the evaporation rate increases with a reducing flow index and an increasing buoyancy effect.

Type
Articles
Copyright
Copyright © The Society of Theoretical and Applied Mechanics, R.O.C. 2008

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