Simultaneous Heat and Mass Transfer in Inclined Channel With Asymmetrical Conditions

This work deals with a numerical study of simultaneous heat and mass transfer with phase change in an inclined channel formed by two parallel plates. The lower one is covered by a thin liquid water film and the upper one is considered impermeable. The plates are maintained at a constant temperature T_W. Ambient air with uniform dry bulb temperature T_in and relative humidity φ_in enters the channel with a uniform upward velocity U_in. The liquid film is assumed to be extremely thin and its temperature is equal to the wall temperature. Steady state conditions are considered and the flow is assumed to be laminar. Viscous dissipation, radiation heat transfer and other secondary effects (pressure work, energy transport by the inter-diffusion of species, Dufour and Soret effects) are neglected. The physical properties are taken constant except for the density in the body forces, which is considered to be a linear function of temperature and mass fraction. Results show that buoyancy forces have an important effect on the hydrodynamic, thermal and mass fraction fields and this effect depends on the channel inclination. A flow reversal chart and analytical correlations for the corresponding critical values of the thermal and solutal Grashof numbers are presented for different channel inclinations.