Abstract:

By considering the momentum source term of surface tension as well as the source term of heat and mass transfer in gas-liquid two-phase flow, a computational model based on the Volume of Fluid （VOF） algorithm was established to describe the heat and mass transfer of two-phase falling film in a plate-type evaporative condenser. Then, the model was used to quantitatively analyze the influences of wall heat flux, inlet liquid temperature and air velocity on the temperature distribution and on the relative relationship between the latent heat transfer density and the sensible one at the gas-liquid interface. The results indicate that the temperatures of liquid membrane and air both increase with the wall heat flux, that the temperature gradient is discontinuous at the gas-liquid interface, that the heat transfer at the gas-liquid interface is mainly the latent heat transfer caused by water evaporation and is assisted by the sensible heat transfer caused by the air, that the heat transfer resistance is mainly due to the water membrane, and that the mass transfer improves with the air velocity.

Key words: plate-type evaporative condenser, heat transfer, mass transfer, gas-liquid two-phase flow, numerical simulation