Characterization of unsteady double-diffusive mixed convection flow with soret and dufour effects in a square enclosure with top moving lid

Abstract

The present study considers the numerical examination of an unsteady thermo-solutal mixed convection when the extra mass and heat diffusions, called as Soret and Dufour effects, were not neglected. The numerical simulations were performed in a lid-driven cavity, where the horizontal walls were kept in constant temperatures and concentrations. The vertical walls were well insulated. A finite volume method based on SIMPLE algorithm was utilized to solve the coupled governing equations. Numerical simulations are performed for wide combinations of Soret and Duofour coefficients and are given by streamlines, isotherms, isoconcentrations, fluid velocities, average Nusselt and Sherwood numbers. The influences of pertinent parameters on the various heat transfer modes, i.e. convective and conductive modes, as well as the total kinematic energy of the studied thermo-solutal system are also analyzed.Results demonstrate that Soret and Dufour effects insignificantly influence the fluid flow and transport phenomena when flow is affected to some extent by the forced convection. It is also achieved that the extra heat diffusion, Dufour effect, affects heat transfer by creating thermal eddies especially when flow is dominated by the natural convection. Besides, the conductive mode of heat transfer is attenuated by Dufour coefficient.

Keywords

• double-diffusive convection
• soret and dufour effects
• heat and mass transfer
• conduction