电站凝汽器非设计工况汽相流动与换热特性的数值预测

采用数值模拟方法计算与比较了一台300MW汽轮机对分式凝汽器在半负荷工况时冷却水管全部工作和一半冷却水管投入工作两种运行方式下的汽相流动与传热特性。计算结果表明，两种运行方式下的汽相流动与传热特性有明显差别。在一半冷却水管运行方式下，虽然管束传热系数较高，但由于冷却面积减半，而且汽阻显著增大，因而凝汽器总体传热效果较冷却水管全部运行时的差，使得抽气口处未凝结蒸汽量上升，空气泵负荷增大。

Numerical Prediction of Steam Flow and Heat Transfer Performance of A Power Plant Condenser at Off-design Condition

The off-design steam flow and heat transfer behaviours of a 300 MW power plant condenser operating with either all or one half cooling water tubes at half-load conditions are numerically analysed and compared. The results show that there are significant differences between the flow and heat transfer behaviours in different operating manners. In the operating manner with the half of cooling water tubes, although the overall heat transfer coefficient of condensers is higher, the overall condenser performance is inferior to that in the operating manner with all cooling water tubes because of less heat transfer area and greater steam pressure loss, so that the residual steam quantity at the outlet of air cooling zone is greater and thus the air pump load is increased.