Combined heat and mass transfer by natural convection from a semi-infinite plate submitted to a magnetic field with Hall currents

Resumo

The present work is concerned with the MHD unsteady free convection flow from a vertical semiinfinite plate of an incompressible electrically conducting fluid. The effects of the viscous dissipation and the Hall currents are analyzed. The unsteady governing equations are reduced to a system of ordinary differential nondimensional equations and the resulting equation system is solved numerically by using the Network Simulation Method. This numerical method is based on the electrical analogy, where only previous spatial discretization is necessary to obtain a stable and convergent solution with very low computational times. To solve the system of algebraic equations with time as continuous function, an electric circuit simulator is used. Numerical results for velocities, temperature, concentration and current terms are illustrated graphically. We have observed that the Grashof number for heat transfer (Gr) and mass transfer (G *) accelerate the velocity of the flow field at all points. But the increase in velocity of the flow field is more significant in presence of mass transfer. The effect of Schmidt number Sc on mass transfer process is a decrease of concentration distribution as a result of decrease of the concentration boundary layer thickness.