Entropy generation in heat and mass transfer in porous cavity subjected to a magnetic field

Abstract

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.

Numerical investigation is carried out to predict the entropy generation for combined natural convection heat and mass transfer in a two dimensional porous cavity subjected to a magnetic field. The Darcy model is used in the mathematical formulation of the flow in porous media. The mathematical model is derived in dimensionless form. The governing parameters arise in the mathematical model are the Rayleigh number, Lewis number, buoyancy ratio and Hartmann number. The entropy generation is obtained as a function of velocity, temperature, concentration gradients and the physical properties of the fluid. The results are presented as average Nusselt number, Sherwood numbers and dimensionless form of local entropy generation rate for different values of the governing parameters.The numerical results show that increasing the magnetic field parameter (Hartmann number) leads to reduce the flow circulation strength in the cavity and this leads to a decrease in the rate of entropy generation.