闭式冷却塔的计算模拟

分析了闭式冷却塔的传热传质机理,建立了其数学计算模型,求解沿塔高度方向的温度分布,采用一维和二维模型对比分析,一维模型每排管为一个单元,二维模型每排管分别划分4个、10个单元,利用Matlab编写圆管型闭式冷却塔程序,与Hasan的结果对比,管内冷却水沿塔高度的温度分布采用二维模型每排管划分4个单元和10个单元相比相差较小,二维模型比一维模型的管内冷却水温度分布更接近Hasan的结果;按二维模型每排管划分10个单元,采用Matlab编写圆管模拟程序,采用分段计算的方法预测冷却水出口水温,与实验结果相比,一致性较好。该模型可用来预测不同流速和不同室外空气状态下闭式冷却塔的出口水温和喷淋水水温。

Simulation of Closed Wet Cooling Towers

The heat and mass transfer of closed wet cooling towers were analyzed,a computational model was presented to predict the temperature distribution along the tower.A comparison between 1-D and 2-D was made.For the 1-D model,each tube row is an element and the 2-D model contains 4 and 10 elements per tube row,respectively.Based on Matlab programming,the cooling procedure program of cooling tower was composed.The difference of cooling water temperature distribution along the tower calculated separately by the 2-D model with 4 elements and with 10 elements is very small.Results obtained by 2-D model are closer to the results given by Hasan than those obtained by 1-D model.Based on Matlab programming,the outlet temperatures of cooling water in tubes were predicted by stepwise calculation with 10 elements per tube row.Compared with the experimental results,it can be seen that the calculated and measurement results are in good agreement.The proposed computational model can be used to predict the outlet cooling water temperatures and the spray water temperatures with variable flow rates and outdoor air conditions.