火电机组直接空冷岛顶部防冻百叶窗仿真计算

To solve the problem that the cooling tube bundle is prone to freeze and crack in the direct air-cooling island under severe cold and strong wind conditions in winter, a kind of anti-freezing shutter device installed between the steam distribution pipes on the top of the air-cooling island was proposed. Through establishing the overall model of the direct air-cooling island and the local model of the air-cooling unit with top shutter, and using Fluent to conduct flow heat transfer calculation, the anti-freezing performance of the anti-freezing shutter in winter and its influence on the performance of direct air-cooling island under opening conditions were studied. The results showed that when the ambient temperature was —20 °C, the wind speed was 20 m/s and the inlet of the fan was blocked, the air flow rate and air temperature in the direct air-cooling island significantly decreased, and the overall heat transfer of the direct air-cooling island was reduced by 52. 7% after closing the shutters at the top of direct air-cooling island. When the ambient temperature is 15 °C without ambient crosswind and the fan was operating at full power, the influence of the opening top shutter on the performance of the air-cooling unit was negligible, in which the air flow loss of the air-cooling unit was 1. 2%, and the heat exchange loss of the air-cooling unit was 2. 2%. In addition, the opening state of the top shutter had no significant impact on the flow field and air temperature inside and outside the air-cooling unit. The device can effectively improve the operating safety of the direct air-cooled island under cold and windy weather in winter.