Thermal performance analysis for high level water collecting wet cooling tower under crosswind conditions

Abstract

Field test was conducted on a high level water collecting wet cooling tower (HWCT) of a 1000 MW unit to investigate thermal performance under crosswind conditions. Firstly, the air temperature distribution above drift eliminators was analyzed, and then the changing rules of water temperature drop ΔT and Merkel number N were researched in this study. The results demonstrated that with the rising of crosswind velocity, crosswind appears an increasingly serious adverse effect on the thermal performance and uniformity of air temperature distribution inside tower. In this paper, χr stands for the radius radio which can indicate the influencing degree of crosswind, and χr is approximately 0.78 when the velocity is less than 2.11 m/s, but around 0.60 at 3.74 m/s. Additionally, the intersection angle θ between cross walls and crosswind direction is introduced to analyze the effect of crosswind direction. The testing results discovered that at the same crosswind velocity, the uniformity of air temperature distribution and thermal performance under θ1 = 5° condition are more superior to those under θ2 = 35° condition. When the crosswind velocity reaches to 3.74 m/s, under θ1 = 5° condition, compared with that of 0.28 m/s, ΔT and N reduce by 12.61% and 12.54%, respectively, however, under θ2 = 35° condition, their reductions reach to 15.34% and 13.58%, respectively. It can be obtained that the thermal performance of HWCTs is relatively more outstanding under the smaller θ and/or the lower crosswind velocity.