冬季自然通风条件下直接空冷凝汽器性能分析

摘要

At low ambient temperature in winter,when the unit's heat load is low,the heat transfer performance of air-cooled condensers under natural ventilation condition is directly related to the safety and economy of air cooling unit's operation.Thus,the heat transfer performance of direct air cooling condensers under natural ventilation condition was investigated.Moreover,the FLU-ENT software was employed to conduct numerical simulation on heat transfer performance of sin-gle-row tube of direct air cooling condenser in a subcritical 330 MW unit,with low wind speed. The results show that,under natural ventilation condition,the air flow inside the air cooling island is mainly driven by the heat pressure difference and suction force;the face velocity of air cooling unit has a certain relationship with the ambient temperature and wall temperature of fin tubes (the face velocity decreases with an increase in the ambient temperature when the fin tubes'wall temperature is kept at a certain value,while it increases with the fin tubes'wall temperature when the ambient temperature is a constant).%分析研究了直接采取冬季自然通风时，直接空冷凝汽器的换热性能，并以某电厂亚临界2×330 MW直接空冷机组为例，利用Fluent软件，对直接空冷凝汽器单排管在小风速下的换热性能进行了数值模拟和计算分析。研究结果表明，冬季自然通风条件下，热压差和抽吸力均为空冷岛空气流动的动力；空冷单元的迎面风速与翅片管束的温度和环境温度有关，保持翅片管束壁面温度不变时，迎面风速随环境温度的升高而减小，当环境温度不变时，迎面风速随壁面温度的升高而增大。