Free convection heat and mass transfer flow in a vertical channel with the Dufour effect

The purpose of this work is to investigate analytically the free-convection and mass transfer flow in a vertical channel formed by two vertical parallel plates. Fully developed laminar flow was considered with uniform temperature and concentration on the plates. The diffusion-thermo effect was taken into consideration. The velocity, temperature, and concentration profiles were obtained analytically using the Laplace transform technique and were used to compute the shear stress, Nusselt number, and mass flux. The present analytical results were compared with those available in the literature without mass transfer and the diffusion-thermo effect and excellent agreement was observed (Singh, A. K., Gholami, H. R., and Soundalgekar, V. M. Transient free convection flow between two vertical parallel plates. J. Heat Mass Trans', 1996, 31, 329-331.). During the course of computation, it was found that the transient solution at large time coincides with the steady-state solution derived separately. The diffusion-thermo effect is observed to create an anomalous situation in temperature and velocity profiles for small Prandtl numbers. The study also revealed that the steady state of the problem is independent of the Dufour effect.