Entropy generation in nanofluid flow due to double diffusive MHD mixed convection.

This work is concerned with the numerical study of laminar, steady MHD mixed convection flow, and entropy generation analysis of A l 2 O 3 -water nanofluid flowing in a lid-driven trapezoidal enclosure. The aspect ratio of the cavity is taken very small. The cavity is differentially heated to study the fluid flow, heat, and mass transfer rate. The adiabatic upper wall of the enclosure is allowed to move with a constant velocity along the positive x -direction. The second-order finite difference approximation is employed to discretize the governing partial differential equations, and a stream-function velocity formulation is used to solve the coupled non-linear partial differential equations numerically. The simulated results are plotted graphically through streamlines, isotherms, entropy generation, Nusselt number, and Sherwood number. The computations indicate that the average Nusselt number and average Sherwood number are decreasing functions of Hartmann number, aspect ratio, and nanoparticle volume fraction. Significant changes in streamlines, temperature and concentration contours for high Richardson number are observed.