冷却塔回流影响数值分析及优化研究

从建筑外观、空间限制、运行噪音等角度考虑,冷却塔一般被布置在隐蔽的区域。冷却塔的布置决定了热湿空气回流的情况,并直接影响冷却塔的运行性能。横流冷却塔侧面进风,逆流是塔身下部四周进风。冷却塔回流导致进风温湿度增高,同时,恶化周边微环境。采用数值模拟方法研究逆流与横流冷却塔布置方式的回流及影响。通过对比2种塔进风口空气的温升,来判断两种塔的回流量情况,并提出可行的措施来减少回流量。模拟表明逆流的进风温升和回流率都低于横流的,是因为逆流布置使进风气流更均匀,且排风风速大。模拟了横流冷却塔出风圆管口加15°向上百叶、加2.2 m进风百叶的优化措施,该措施可有效减少回流量。研究结果可为工程设计提供参考,以降低由于冷却塔设计不当引起不利的回流影响。

Numerical Analysis and Optimization Research on Backflow Effect of Cooling Tower

Cooling towers are usually located in concealed areas from the standpoint of building appearance, space limitations and operational noise.The arrangement of the cooling towers determines the hot and humid air backflow, which directly affect the performance of the cooling tower.The air enters into the cross-flow cooling tower through the side of the tower, but into the counter-flow cooling tower through the four sides of the lower part of the tower.Backflow air leads to rise of air temperature and humidity, while deteriorating the surrounding micro-environment.The numerical simulation method is used to study the backflow and influence of the counter-flow and cross-flow cooling tower arrangement.The backflow two towers are judged by comparing their air inlet temperature, proposing the feasible measures to reduce the backflow.The simulation shows that the counter-flow cooling tower''s inlet air temperature rise and the reflow rate are lower than the cross-flow cooling tower, because the counter-flow arrangement makes the inlet air flow more evenly, the exhaust wind speed is larger.The optimization of cross-flow cooling tower is simulated, including the outlet tube adding 15° upward louver and adding 2.2 meters of air louver inlet, which are found to effectively reduce the backflow.The results can provide a reference for engineering design to reduce adverse design effects due to improper cooling tower design.