不同环境风速影响下的外冷系统运行特性研究

Operating Characteristics of External Cooling System under the Influence of Different Ambient Wind Speeds

环境风场及周围建筑物是影响外冷系统流体传热性能的重要因素。基于锡盟2×300 Mvar调相机外冷系统,采用CFD仿真分析获得外冷系统的空气流场及温度场,通过计算空冷器的进风平均温度及热风回流率,分析了外冷系统流体传热性能的空间分布特性。结果表明,由于环境风的扰动压制作用及风向上游挡风墙的隔断作用,在环境风速3.4 m/s下,整个外冷系统进风平均温度比环境温度高1.9℃,表明外冷系统周围形成了一个热岛区域;随着环境风速的增大,空冷器的进风平均温度及热风回流率下降;处于风向上游的①号外冷系统空冷器的进风平均温度及热风回流率低于下游的②号外冷系统空冷器,①号外冷系统各组空冷器回流率波动幅度在0.25之内,②号外冷系统各组空冷器回流率波动幅度在0.07之内;空冷器的热风回流率呈空间分布特性,为外冷系统的布置设计和运行研究提供理论参考。

The wind field and surrounding buildings bring significant effect on the fluid flow and heat transfer of the outer cooling system.Based on the outer cooling system of Ximeng synchronous phase modifier,the flow and temperature field are presented by CFD simulation.By means of the inlet average temperature and exhaust plume recirculation flow ratios of the air cooler,the space-dependent characteristics of the fluid flow and heat transfer performance are analyzed.The results show that under the wind speed of 3.4 m/s,the inlet average temperature of the outer cooling system is 1.9℃higher than ambient temperature due to the influence of wind and windshield,it shows that a heat island region is formed around the outer cooling system.With the increase of wind speed,the inlet average temperature and exhaust plume recirculation flow ratios of the air cooler decrease.The inlet average temperature and exhaust plume recirculation flow ratios of the air cooler of NO.1 outer cooling system upstream are lower than those of NO.2 outer cooling system downstream under the influence of wind and windshield.The exhaust plume recirculation flow ratios fluctuation of the air cooler of NO.1 outer cooling system is within0.25.The exhaust plume recirculation flow ratios fluctuation of the air cooler of NO.2 outer cooling system is within 0.07.The space-dependent characteristics of the exhaust plume recirculation flow ratios vary with the wind speed.The theoretical basis for the layout design and operation research of the outer cooling system is provided.