Effect of thermophoresis on mass transfer from a mixed convection flow along a vertical permeable surface with a variable surface heat flux

A theoretical Study of thermophoretic effect on mass transfer from a mixed convection flow along a vertical permeable surface is proposed. The flow was modeled as a two-dimensional, incompressible and steady-state laminar flow driven by a combination of forced convection and natural convection. The mixed convection flow is considered through a porous medium over a vertically permeable surface with suction/injection and a variable heat flux, q(w)(x) = Ax(n) embedded in a non-Darcian porous medium. The transport mechanisms were coupled using inertia, mixed and non-Darcian convections, suction/injection flow and thermophoresis. Similarity analysis and Runge-Kutta integration with shooting scheme were used to determine the velocity, temperature and concentration fields. In addition, a finite- difference scheme solution was obtained to do a comparison with the results from the Runge-Kutta integration. The results showed that the effects of thermophoresis, suction/injection, mass diffusivity and buoyancy force on the mass transfer rates are strong, particularly for different Schmidt number at hot wall surface conditions. The thermophoretic effect is from the temperature gradient that decreases the mass transfer to the hot wall surface.