摘要
单机容量达到百万k W的直接空冷火电机组空冷岛具有庞大的体积和更多的空冷单元,环境风导致的系统性能空间分布不均匀性更为明显。空冷岛的结构与布局优化,为百万k W空冷机组应对环境风不利影响提供了可行的技术途径。针对2×1 000 MW直接空冷机组,建立物理数学模型,考虑环境自然风和空冷单元轴流风机输运空气流的耦合作用,采用数值模拟方法,获得空气侧流场和温度场的三维分布。特别针对实际运行中最为不利的锅炉后来风,在不同风速,以及空冷岛和主厂房不同距离条件下,从机理上解释空冷岛冷却通风流量和换热性能的变化规律。结果表明:随着环境风速增加,空冷岛的换热能力降低;距离增大,随风速增加换热性能恶化的趋势更为显著;环境风速大于6 m/s时,距离越大,热风回流率越高;相比于其他更大距离的布置方式,距离15 m布置方式流动换热性能更好;环境风速较大的情况下,紧密的空冷电站建筑布局,更有利于抵御大风的不利影响。
Air-cooled condensers （ACCs） of direct air-cooled plant with unit capacity of 1 000 MW have huge size and more ceils, and the inhomogeneity of system performance in space distribution by ambient wind is obvious. The optimization of the structure and layout can provide feasible technical approach for 1 000 MW ACCs to replay to ambient wind. On the basis of 2 x 1 000 MW direct air-cooled units, this paper constructed physical and mathematical models with considering the coupling effect of ambient wind and air flow from unit fans, and presented the three-dimensional distribution of flow and temperature fields by using numerical simulation method. Then the variation mechanism of the cooling ventilation flow rate and heat transfer performance of ACCs with wind speed and distance between ACCs and the main buildings was explained, especially for the wind from boiler house which was most unfavorable. The results show that the heat thermo-flow performance of ACCs is decreased with the increase of the wind speed. With the increase of wind speed, the heat capacity decreases more rapidly when the distance between ACCs and the main buildings increases. When the wind speed is over 6 m/s, the exhaust plume recirculation flow ratio increases with the distance increases; the heat transfer performance of 15 m is better than other more lager distance. Therefore it＇s benefit to resist adverse effect by strong wind with tight air-cooled plant layout at high wind speed.
出处
《电力建设》
北大核心
2015年第6期7-13,共7页
Electric Power Construction
基金
国家重点基础研究发展计划项目(973项目)(2015CB251503)~~
关键词
直接空冷
空冷岛
流动传热特性
距离
热风回流率
direct air-cooled
air-cooled condenser （ACC）
thermo-flow performances
distance
exhaust plume recirculation flow ratio
