环境风对空冷岛换热性能影响的分析及其改善措施

摘要

Using a CFD software,take one 2 ×300MW direct air-cooled unit as an example,proceeding numerical simulation with a two-step method.Analysed the effect of different wind velocity and different wind direction on exterior flow field and Heat exchange efficiency.Find out the reasons for hot air reflow and fan output reducing.The heat transfer performance of air-cooled island was affected after installation of windproof net.The result show that a low-pressure is the main reason for hot air reflow and fan output reducing;A better flow field should be got after installing the windproof net,the volumetric effectiveness increased 8.5％ at a wind speed of 9m/s.%利用CFD软件,采用分步建模的方法对某2×300MW直接空冷凝汽器进行了数值模拟.分析了不同风向和风速对空冷岛外部流场和空冷凝汽器换热效率的影响.找出了环境风影响下热风回流和空冷单元风机出力降低的原因.空冷岛安装防风网,其换热性能会受到防风网的影响.结果表明,低压区的形成是导致热风回流和风机出力降低的主要原因;加装防风网可以有效改善风机入口流场,在风速为9m/s时,可以提高风机容积效率8.5％.