冷却塔评价指标研究与冷却数应用

Cooling Tower Performance Evaluation Index and Application of Cooling Number

为了研究各类冷却塔性能评价方法的优劣,对冷却幅高评价法、冷却效率系数评价法、冷却水温对比法、冷却水量对比法、通风量以及冷却数等6种评价方法进行了综述。并以某电厂600 M W机组的自然通风逆流湿式冷却塔为例,通过采用布置导风板改善冷却性能的方法,重点研究了以冷却数评价指标为基准的导风板选型优化。结果表明:冷却数对气-水直接蒸发换热过程强弱有直观的反映,配合通风量指标,可以同时考虑到对热力过程的评价与对空气动力性能的评价;导风板安装角为40°时的冷却效果最佳,此时气流进入冷却塔切向角适中,空气流场均匀,冷却数最大;旋流叶片弧度为30°时的优化率为12.2%,此时气流进塔受到的缓冲适中,冷却数最大。

In order to study the advantages and disadvantages of various methods for evaluating the performance of cooling towers,six evaluation methods such as cooling amplitude evaluation method,cooling efficiency evaluation method,cooling water temperature comparison method,cooling water quantity comparison method,ventilation amount and cooling number are reviewed.Taking the natural ventilation counterflow wet cooling tower of a 600 MW unit in a power plant as an example,the method of arranging the air deflector is adopted to improve the cooling performance,and the optimal selection of the air deflector is focused on based on the cooling number index.The results show that the cooling number has a direct reflection on the advantages and disadvantages of the direct evaporative heat transfer process;the cooling number is matched with the ventilation index,which can simultaneously consider the evaluation of the thermal process and the evaluation of the aerodynamic performance;the cooling effect is best when the installation angle of the air deflector is 40°.At this time,the airflow enters the cooling tower with a moderate tangential angle,the air flow field is uniform,and the cooling number is the largest;the optimization rate is 12.2%when the blade curvature is 30°.At this time,the airflow entering the tower is moderately buffered and the cooling number is the largest.