环境风对直接空冷凝汽器性能的影响及主导因素分析

环境风对直接空冷凝汽器的换热性能具有重要影响.以某300MW直接空冷机组为例,分步建立了空冷岛和每个空冷单元的数值分析模型.分析了环境风对直接空冷凝汽器换热性能的影响,得到了环境风工况下影响空冷凝汽器换热性能的主导因素.结果表明：位于空冷平台边缘的空冷单元,由于受到热风回流和倒灌的影响,其入口风温受环境风的影响较大;位于空冷平台迎风侧的空冷单元,因为负压区的存在降低了风机的性能,使其进气量受环境风的影响较大;空冷单元因风机性能下降所导致的进气量减少是造成空冷凝汽器性能降低的主导因素.

Performance of Direct Air-Cooled Condenser Under Windy Conditions and Its Influencing Factors

The environmental wind has significant effects on the heat transfer efficiency of direct air-cooled condensers.By way of the example of a 300-MW direct air-cooled condenser,the models of the air-cooled island and the heat exchanger units are built for numerical analysis.The effects of the environmental wind on the heat transfer efficiency of the air-cooled condenser are studied,and the dominant factor contributing to the reduction of the efficiency under windy conditions is found out.The result shows that the air inlet temperature at the edge of the heat exchanger units is greatly influenced by the environmental wind due to the hot air recirculation and the backward flow;the air inflow of the heat exchanger units on the upwind side is also seriously affected by the environmental wind since there is a negative pressure zone existing that lowers the performance of the fan.The decrease of the air inflow due to the fan performance degradation is the major factor affecting the performance of the air-cooled condenser.