关键词: 冷却塔, 传热传质, 两相流, 数值分析

Abstract: Abstract: Based on CFD code FLUENT and heat and mass transfer theory, the governing equations of air and water and the theory model of heat and mass transfer between air and water were set up for a natural draft counterflow wet cooling tower (NDWCT). The models of forces brought to each phase were set up resorting to discrete phase model and experimental correlation. Adopting the standard k-ε model to close the Reynolds average equations, the threedimensional heat and mass transfer process in NDWCT was simulated and analyzed. The fields of air velocity, temperature and moisture content show that there are regions where the temperatures of air and cooling water are less than the ambience dry bulb temperature in a rain zone, which also indicates that the longitudinal eddy upon the inlet has a negative effect on the local intensity of heat and mass transfer. The cooling water evaporation rate in each zone was computed and investigated. The water mass flow rate radial distribution curves at different heights and the distribution field of the mass flow rate ratio of air to water were given to analyze the evaporation intensity, which indicated that heat and mass transfer mainly occurs in the fill zone.

Key words: cooling tower, heat and mass transfer, two-phase flow, numerical analysis