环境背风对直接空冷凝汽器外部流场的影响

通过数值模拟分析了某台300MW机组直接空冷凝汽器冷凝单元的流场及散热情况,以无风和风速3、5m/s为例,研究环境背风对空冷凝汽器的影响。结果表明,流经冷凝单元两侧的气流温度较高,A型架内侧底部4个角区有强列的涡流,散热效果不明显;环境背风会导致较强的热风回流,极大地降低换热性能,并且换热性能的降低与高大建筑物所引起的绕流效应关系密切。无风和风速为3、5m/s时的总换热量分别为807、516、540MW,说明在环境背风风速不高的情况下,略提高风速,换热性能有较小提高。

INFLUENCE OF ENVIRONMENTAL LEEWARD ON THE EXTERNAL FLOW FIELD OF DIRECT AIR-COOLED CONDENSER

Flow field and heat dissipation situation of the condensate unit on a direct air-cooling condenser for a 300 MW unit was simulated.To study the adverse effect of environmental leeward on air-cooled condenser,wind speed at 0 m/s,3 m/s,5 m/s were taken as examples respectively.Results show that,the temperature of air flowing through the condensate unit is higher,inside the A-shape shelf,at the bottom 4 corners,there’s strong vortex,and heat dissipation is not obvious.The heat transfer performance will be reduced extremly because of the strong hot air reflow caused by environmental leeward,that is closely related with the flow around effect resulted from tall buildings.The total heat exchange amount was 807 MW,516 MW and 540 MW when the wind speed was as mentioned 0 m/s,3 m/s and 5 m/s,respectively,this indicates that,when the environmental leeward flow rate is not very high,slightly increasing the wind speed can improve the heat transfer performance a bit.