NUMERICAL STUDY OF DOUBLE DIFFUSIVE MIXED CONVECTION IN HORIZONTAL CHANNEL WITH COMPOSITE OPEN POROUS CAVITY

Numerical simulation of heat and mass exchange in a composite open cavity connected to a horizontal channel is investigated. A porous layer forms the lower part of the open cavity. One of the vertical sides of the cavity is kept at constant temperature and adjusted with constant concentration. The other walls of the cavity and channel are thermally insulated. The governing equations are solved by finite element method. The fixed parameters throughout the study are Prandtl number, Pr = 6.26; Darcy number, Da = 10(-3) ; buoyancy ratio, N = 0.5; and Lewis number, Le = 20. The governing parameters are Reynolds number (Re = 50-250), Richardson number (Ri = 0.01-100), and thickness of porous layer (H-p = 0.25-1). These three parameters are studied for two cases of heat and species sources, opposing and assisting cases. The results showed that the opposing case gives maximum convective heat transfer, where for Ri = 0.01, the percentages increase of Nusselt number between the opposing and assisting cases are 53.07 and 90.18% at Re = 50 and 250, respectively; whereas, for Ri = 100, the percentages increase are 36.30 and 17.81%.