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在大风情况下,空冷凝汽器换热效率由于热风回流和“倒灌”现象的共同作用而降低。为了改善环境风对空冷凝汽器的影响,提出了在空冷岛背风侧(主导风向下)加装挡风墙的方案。以某600 MW直接空冷机组为例,利用计算流体动力学(computational fluid dynamics,CFD)软件对空冷岛外部流场进行数值模拟,分析主导风向、主导风向相反风向情况下,不同风速时挡风墙对空冷凝汽器换热效率的影响。结果表明:在主导风向下,加装挡风墙使空冷单元空气流量大幅度增加,空冷凝汽器换热效率提高;在主导风向相反风向下,加装挡风墙造成空冷岛背风侧出现热风回流,空冷凝汽器换热效率降低,在背风侧水平挡板边缘处竖直加装一定高度的挡风墙可以改善热风回流现象。
In the case of high winds, the heat transfer efficiency of the air-cooled condenser is reduced due to the combination of the hot air return and the “backfill” phenomenon. In order to improve the influence of ambient air on the air-cooled condenser, a scheme of installing a wind wall on the leeward side of the air-cooled island (under the prevailing wind direction) is proposed. Taking a 600 MW direct air-cooled unit as an example, the CFD software was used to simulate the flow field outside the air-cooled island. The main wind direction and dominant wind direction were analyzed. Effect on heat transfer efficiency of air-cooled condenser. The results show that under the prevailing wind direction, the installation of the wind shielding wall increases the air flow rate greatly and the heat exchange efficiency of the air-cooled condenser increases. In the opposite wind direction, the installation of the wind shielding wall causes the hot air on the leeward side of the air-cooled island Reflux, air-cooled condenser heat exchanger efficiency is reduced, in the leeward horizontal baffle edge vertical installation of a certain height of the wind wall can improve the hot air backflow phenomenon.