摘要
双系统自然通风逆流式冷却塔是最近出现的一种同时有两个相互独立热负荷的冷却塔;当两个机组负荷相同时与传统冷却塔相同,当两个机组负荷不同时,传统热力计算方法将不再适用。本文在对塔内的冷热空气掺混与密度作沿高度线性变化假设的基础上,将两个不同热负荷塔区的空气质量加权平均后的密度作为塔出口空气密度,推导出了冷却塔的抽力和热力计算公式,冷却塔的阻力系数是通过模型试验获得的。通过实例计算与分析表明该方法的计算误差不大于0.4℃,双系统冷却塔在两种不同负荷运行时的出塔水温比单系统冷却塔高,正常运行时保持两个系统热负荷接近可降低出塔水温。该方法可供双系统冷却塔设计、运行参考。
The thermal analysis on natural counter flow cooling tower for two generating units are carried out.Based on the assumptions that the mixing of cool and heated air as well as the variation of air density obeys the linear law along the height of tower,the weighted average density of air in two regions of the tower corresponding to different generating units is regarded as the air density at the outlet to deduce the formula for draft force and thermal calculation.The resistance coefficient of the cooling tower is obtained from model test.The application of this method shows that the calculation error is less than 0.4℃.The cooling water temperature of the tower is higher than that designed for single unit when two heat loads working at different outputs,but it will be reduced if two heat loads are the same.
出处
《水利学报》
EI
CSCD
北大核心
2008年第1期79-82,90,共5页
Journal of Hydraulic Engineering
关键词
双系统
自然通风逆流式
冷却塔
热力计算方法
thermal analysis
natural draft counter flow cooling tower
two heat loads
thermal calculation method
