横向风速影响下湿式冷却塔内温度场及防冻措施的数值研究

Numerical Study on the Temperature Field in Wet Cooling Tower and the Anti-icing Measures Under the Influence of Horizontal Wind Speed

针对我国北方冬季气温较低和冷却塔内换热不均引起的填料下表面、进风口、基环面等处易结冰问题,需在塔的进风口处加装一定数量挡风板。论文建立冷却塔传热传质模型,采用Fluent模拟软件,模拟并分析在不同的风速下塔内空气温度场、最低水滴温度和最低空气温度,以及加装挡风板的最佳层数的变化规律;结果表明:1)低风速(小于4 m/s)塔内的背风面区域空气温度较高,随着风速的增加,高温区逐渐向迎风侧转移;2)特征平面的最低水滴温度、最低空气温度随着风速的增加先升高再降低,在风速V 4 m/s达到最大值;3)当环境温度为263.15 K、风速为2、6、8 m/s,挂1层挡风板可有效防止塔内结冰;当环境温度为256.15和250.15 K时,风速分别为2、4、6、8 m/s,分别挂1、1、2、4和4、1、3、5层挡风板可有效防止塔内特征面最低水滴结冰。

To solve the icing problems in wet cooling towers at areas such as the bottom surface of filler, air inlet and base torus caused by the low temperature in northern China and heat disparity in the cooling tower, windshield boards are generally installed at the air inlet. The study established a heat and mass transfer model of the wet cooling tower. By using the software of Fluent, this paper mainly simulated and analyzed the changing regularity of the air temperature field, the minimum water temperature, the minimum air temperature and the optimal layers of the windshield board under the different wind speed. The results indicate that： 1） while the wind speed is lower than 4rn/s, the air temperature in the leeward of cooling tower is higher, and the higher temperature zones move to the windward of the cooling tower with the increasing of wind speed. 2） The minimum water temperature and the minimum air temperature of the characteristic plane increase at first and then reduce with the increase of horizontal wind speed. And these two temperatures reach the maximum when the horizontal wind speed is 4 rn/s. 3） When the environment temperature is 263.15 K and the wind speeds respectively are 2, 6 and 8 m/s, hanging 1 layer of windshield can effectively prevent the characteristics of plane from being frozen; When the environment temperature is 256.15 K and the wind speeds respectively are 2, 4, 6 and 8m/s, the optimal layers of windshield which prevent the characteristics of planes from being frozen are 1, 1, 2, 4 layers; When the environment temperature is 250.15 K and the wind speeds respectively are 2, 4, 6 and 8 m/s, the optimal layers of windshield which prevent the characteristics of planes from being frozen are 4, 1, 3 and 5 layers.