环境风对空冷岛内部涡流分布的影响

Environmental Wind Impact on Eddy Current Distribution in Air Cooling Island

随着环境风速的变化,空冷岛内部涡流分布对空冷单元换热器性能的影响愈加重要。以2×600MW的直接空冷机组为研究对象,采用Fluent软件模拟了环境因素对空冷岛内部流场的影响。针对不同的环境风速,分析了空冷机组周围流场温度和压力的分布情况,研究了涡流产生的机理和变化规律,以及环境风速对空冷机组风机流量的影响。结果表明:随着环境风速的增大,热空气羽流倾角增大,空冷单元与周围环境的换热量相对减少,换热效率降低。空冷单元呈现更多的负压区域,流场内出现涡旋并逐渐在增大,此时出现回流情况。另外,各空冷单元风机进口流量整体呈下降趋势,其中迎风侧的第一个风机f1的进口流量降幅最大,整体下降298.54kg/s;其功率的降幅也最大,下降了14.338kW。对此提出了优化运行改进措施。

With the change of environment wind velocity,the influence of eddy current distribution in air cooling island on the performance of direct air-cooling unit becomes increasingly important.This paper simulated the influence of environmental wind on the internal flow field of the air-cooled island by Fluent for a 2×600MW direct air-cooling unit.According to optional speeds of surrounding wind,we analysed the distribution of temperature and pressure,studied the mechanism and variation of eddy current,and discussed the effect of ambient wind speed on the flow rate of the air-cooled unit fan.The results show that:with the airflow velocity rising,the inclination of hot air plume increases,resulting in a reduction in heat transfer volume and heat transfer efficiency.And more negative pressure areas ware present in the air cooling unit.What's more,the vortices appeared in the flow field of air cooling unit and gradually increase,as well as the circumfluence occurs.The inlet flow of each fan showed a downward trend as a whole.The f1 had the greatest decrease in the inlet flow and the greatest decrease in power,which were 298.54kg/s and 14.338kW respectively.In this regard,the improvement measures for optimizing operation are put forward.