Mixed convection heat and mass transfer in vertical rectangular ducts

Abstract

The present study deals with the numerical prediction of mixed convection heat and mass transfer in a vertical rectangular duct with film evaporation along the porous wall. The Boussinesq approximation is invoked to take into account the buoyancy effect induced by thermal and mass diffusion. Computations are made here for the wetted wall temperature Tw = 40°C and 60°C, relative humidity of moist air at the inlet Φ = 10, 50 and 90%, and the through-flow Reynolds number Re = 1000 and 2000. The numerical results, including the developments of velocity, temperature, concentration, Nusselt number, Sherwood number and friction factor, are presented. Predicted results show that the influences of the combined buoyancy force of thermal and solutal diffusion on the flow, heat and mass transfer are significant. Due to the film evaporation along the wetted wall, the mass transfer is found to enhance the heat transfer rate along the wetted wall. Additionally, the results disclose that the heat transfer along the wetted wall is predominated by the latent heat transfer connected with film vaporization.