空冷凝汽器波形翅片扁平管管束外空气流动传热特性

研究火电站空冷凝汽器广泛采用的波形翅片扁平管管束外空气流动传热特性，对于火电站空冷岛的设计与运行都具有重要意义。该文通过CFD模拟，得到不同空冷凝汽器迎面风速条件下冷却空气的流场和温度场，通过计算获得了空冷凝汽器冷却空气平均对流换热系数和摩擦系数随翅片间距和翅片高度的变化规律。结果表明：随空冷凝汽器迎面风速增加，空气对流换热增强，摩擦系数降低。对每个迎面风速而言，都存在一个最佳翅片间距，对流换热最强。翅片高度增加，对流换热系数和摩擦系数减小。对空冷凝汽器波形翅片管束空气流动传热性能综合评价指标的分析表明，最佳翅片间距和高度需要通过综合技术经济比较确定。

Flow and Heat Transfer Characteristics of Cooling Air Outside the Flat Wave-finned Tube Banks of Air-cooled Condensers

It is of great use to study the flow and heat transfer characteristics of cooling air outside the flat wave-finned tube banks that are commonly used by air-cooled steam condensers in power plant. The velocity and temperature fields were obtained and the variations of mean convection heat transfer coefficient and friction coefficient with fin space and fin height were presented by using CFD simulations. The results show that the convection heat transfer will be enhanced and the friction coefficient will become lower with the windward air velocity of air-cooled condensers increasing. There exists an optimal fin space in which the convection heat transfer is the most powerful for every windward air velocity. The convection heat transfer coefficient and the friction coefficient both decrease with the fin height increasing. The general performance evaluation for the flow and heat transfer of air outside the flat wave-finned tube banks was investigated. It shows that the optimal fin space and height should be determined by the integrated technical and economical analyses.