NUMERICAL SIMULATION OF DOUBLE-DIFFUSIVE MIXED CONVECTION IN A HORIZONTAL ANNULUS UNDER TANGENTIAL MAGNETIC FIELD, WITH A ROTATING OUTER CYLINDER

Double-diffusive mixed convection in a horizontal annulus under combined buoyancy effect of temperature and concentration gradients and in the presence of a tangential magnetic field is studied numerically. Different constant temperatures and concentrations are imposed along the inner cylinder and the outer cylinder, and a steady-state laminar condition is considered. The governing equations consisting of continuity, momentum, energy, and spices transfer equations in dimensionless form are solved using an in-house Fortran code based on the Patankar-Spalding SIMPLE algorithm. The results are reported in terms of streamlines, isotherms, and isoconcentrations for different values of governing parameters such as the Reynolds number, Rayleigh number, Hartmann number, and the Lewis number. In addition, the results for heat transfer rate and mass transfer rate are presented in terms of local and average Nusselt numbers and local and average Sherwood numbers, respectively, for various parametric conditions. Throughout the present study, the Prandtl number and buoyancy ratio are considered constant, 0.71 and -1, respectively, while the other parameters vary in the following intervals: 5 x 10(3) <= Ra <= 5 x 10(4), 10 <= Re <= 200, 0 <= Ha <= 200, and 0.01 <= Le <= 5.