自然通风冷却塔加装十字挡风墙数值研究

Numerical Study of Installing Cross-windbreak on Natural Draft Cooling Tower

基于CFD软件和自然通风湿式冷却塔相关理论,对喷淋区和雨区采用离散相模型计算,对填料区建立了基于Poppe理论的数值求解模型,并通过编译自定义源项函数,实现其在Fluent中的求解。在该模型基础上,分析了横向风速对冷却塔热力性能的影响;最新提出了在雨区加装改进的十字挡风墙的措施,并引入多孔跳跃模型实现其数值求解。计算结果表明:横向风对出塔水温影响很大,当风速为6 m/s时,出塔水温最高,比无风时高1.34℃;改进的十字挡风墙能有效提高冷却塔性能,最大能使出塔水温降低0.32℃,并且能明显降低水损失。

This paper simulates and analyzes the effect of crosswind on the thermal performance of natural draft wet cooling tower, and, according to the result,it puts forward a feasibility advice of installing cross-windbreak in rain zone. The current simulation adopts discrete phase model in the spray and rain zone, and uses user-defined source terms to represent the heat and mass transfer which is b＇ased on the Poppe theory in fill. Results from the current investigation demonstrate that the effect of crosswind on water outlet temperature is significant. The highest water outlet temperature,which appears when crosswind veiocity is 6m/s , is higher than no crosswind condition by 1.34℃. Installing improved cross -windbreak is effective for reducing water outlet temperature and water loss at inlet. The maximum temperature drop of water outlet temperature is 0.32 ℃.