Three-Dimensional Thermal Performance Investigation of Natural Draft Counter-flow Wet Cooling Tower

摘要

From the aerodynamic fields around the tower air inlet and across the heat and mass transfer zone, and the water temperature field above the water bond surface, this paper clarified the three dimensional characteristics of heat and mass transfer in natural draft counter-flow wet cooling tower (NDCWT), and denoted the necessity of three dimensional investigation on NDCWT. Based on the experimental data of some NDCWT with 5 500 m2 fill area, this paper analyzed the impact of ambient crosswind on the air velocity distribution around tower air inlet, the air mass flowrate through tower, the water temperature drops in each zone etc. The investigation indicated that the ambient crosswind induced the nonuniformity of inflowing air around tower air inlet, reduced the air mass flowrate into tower, destroyed the circumferential uniformity of aerodynamic field, and caused longitudinal vortex under the windward fill, so as to decrease the effective fill cooling area and debase the total thermal performance of NDCWT. This study suggested that the threedimensional investigation of NDWCT thermal performance was very significant.