Heat and Mass Transfer of a Non-Newtonian Fluid Flow over a Permeable Wedge in Porous Media with Variable Wall Temperature and Concentration and Heat Source or Sink ALI J. CHAMKHA Manufacturing Engineering Department The Public Authority for Applied Education and Training P. O. Box 42325 Shuweikh, 70654 – KUWAIT E-mail: chamkha@paaet.edu.kw Abstract: - The problem of steady, laminar, coupled heat and mass transfer by mixed convective flow of a non- Newtonian power-law fluid over a permeable wedge embedded in a porous medium with variable surface temperature and concentration and heat generation or absorption and wall transpiration effects is considered. A mixed convection parameter for the entire range of free-forced-mixed convection is employed and a set of non-similar equations are obtained. These equations are solved numerically by an efficient implicit, iterative, finite-difference method. The obtained results are checked against previously published work for special cases of the problem and are found to be in good agreement. A parametric study illustrating the influence of the various physical parameters on temperature and concentration profiles as well as the local Nusselt and Sherwood numbers is conducted. The obtained results are illustrated graphically and the physical aspects of the problem are discussed. Key-Words: - Mixed convection, porous media, heat and mass transfer, heat generation/absorption, non-Newtonian fluid, wall transpiration. 1 Introduction Convection heat transfer from vertical surfaces and wedges embedded in porous media has been the subject of many investigations. This is due to the fact that these flows have many engineering and geophysical applications such as geothermal reservoirs, drying of porous solids, thermal insulation, enhanced oil recovery, groundwater pollution, and underground energy transport. Cheng and Minkowycz [1] have presented similarity solutions for free thermal convection from a vertical plate in a fluid-saturated porous medium. Ranganathan and Viskanta [2] have considered mixed convection boundary layer flow along a vertical surface in a porous medium. Nakayama and Koyama [3] have suggested similarity transformations for pure, combined and forced convection in Darcian and non-Darcian porous media. Lai [4] has investigated coupled heat and mass transfer by mixed convection from an isothermal vertical plate in a porous medium. Hsieh et al. [5] have presented non-similar solutions for combined convection in porous media. Yih [6] has studied the effect of uniform suction/blowing on heat transfer of MHD Hiemenz flow through porous media. Kumari et al. [7] have studied mixed convection flow over a vertical wedge embedded in highly porous medium. Yih [8] has reported on the radiation effects on the entire regime of mixed convection over an isothermal wedge in the porous media. Also, Yih [9] has studied coupled heat and mass transfer in mixed convection over a wedge with variable wall temperature and concentration in porous media. All of the above references considered Newtonian fluids. A number of industrially important fluids such as molten plastics, polymers, pulps, foods and slurries and fossil fuels which may saturate underground beds display non-Newtonian fluid behavior. Non-Newtonian fluids exhibit a non-linear relationship between shear stress and shear rate. Chen and Chen [10] have presented similarity solutions for free convection of non- Newtonian fluids over vertical surfaces in porous media. Mehta and Rao [11] have investigated buoyancy- induced flow of non-Newtonian fluids over a non- isothermal horizontal plate embedded in a porous medium. Also, Mehta and Rao [12] have analyzed buoyancy-induced flow of non-Newtonian fluids in a porous medium past a vertical plate with non-uniform surface heat flux. In a series of papers, Gorla and co- workers [13-18] have studied mixed convection in non- Newtonian fluids along horizontal and vertical plates in porous media. Also, Mansour and Gorla [19] have studied mixed convection–radiation interaction in power-law fluids along a non-isothermal wedge embedded in a porous medium. Jumah and Mujumdar [20] have considered free convection heat and mass transfer of non-Newtonian power-law fluids with yield stress from a vertical flat plate in saturated porous WSEAS TRANSACTIONS on HEAT and MASS TRANSFER Ali J. Chamkha ISSN: 1790-5079 11 Issue 1, Volume 5, January 2010