EFFECTS OF FILM VAPORIZATION ON TURBULENT MIXED CONVECTION HEAT AND MASS-TRANSFER IN A VERTICAL CHANNEL

Effects of combined buoyancy forces of thermal and mass diffusion on t urbulent forced convection heat and mass transfer in downward flow wer e numerically examined in detail. Results are presented for air-water system under different conditions. Particular attention is paid to inv estigating the role of latent heat transport associated with the film vaporization in turbulent mixed convection heat and mass transfer. Pre dicted results show that the heat transfer along the gas-liquid interf ace is dominated by the latent heat transfer. The results also show th at the assumption of an extremely thin film thickness made by Lin et a l. [J. Heat Transfer 110, 337-344 (1988)] is inappropriate, particular ly for a system with a large liquid mass flow rate B. Additionally, it is found that the opposing-buoyancy forces would cause an enhancement in heat and mass transfer results compared with the corresponding res ults of forced convection. And the extent of enhancement in heat and m ass transfer coefficients increases with the increase in T-w or q''(w) .