直接空冷凝汽器单排翅片管外部流动及换热特性分析

Analysis of Extratubal Flow and Heat Transfer Performance for Finned-tube of Direct Dry Air-Cooled Condenser

蛇形翅片管是直接空冷凝汽器的核心换热元件。对其进行详细的换热流动分析,对直接空冷系统的设计以及运行都具有非常重要的意义。应用计算流体力学(CFD)数值模拟的方法,在不同迎面风速下,对翅片管的流动特性和换热性能进行了深入分析,并得出了翅片管的压力降、摩擦系数、换热量、换热系数、出口温度、翅片温度等随迎面风速变化的曲线,提出了努塞尔数Nu与雷诺数Re之间的无因次关系式,所得到的结果可为我国电站空冷系统的设计和运行提供理论依据。

Finned-tube is a key element of heat transfer of direct air-cooled condenser（DACC） which is a forced draught air-cooled condenser.The research on the flow and heat transfer performance of DACC is of great importance in the design and operation of DACC.Under different windward velocity,the flow and heat transfer performances of the finned-tube have been calculated and analyzed based on Computational Fluid Mechanics（CFD）.The relationships between pressure drop,fractional coefficient,heat exchange capacity,convection coefficient,outlet temperature,finned-tube temperature and windward velocity and also the dimensionless relationship between Nusselt number and Renolds number are presented.The results of the research provide a theoretical basis for the optimal design of DACC.