开孔矩形翅片椭圆管流动与换热特性的数值研究

对电站直接空冷系统的基本换热元件矩形翅片椭圆管建立三维物理数学模型,对空气侧流动和传热性能进行数值研究．分析了不同迎面风速下翅片上无扰流孔和开有扰流孔两种情况下矩形翅片表面的局部表面传热系数分布规律,发现椭圆基管后存在的尾流区使得翅片的强化换热作用减弱。比较了扰流孔的尺寸、数目和位置对管外空气侧流动与换热的影响,结果表明:扰流孔尺寸对流动与换热存在明显影响,而扰流孔数目和位置的影响相对比较小．

THE FLOW AND HEAT TRANSFER CHARACTERISTICS OF NUMERICAL INVESTIGATION OF RECTANGULAR-FIN ELLIPTIC-TUBE WITH INTERRUPTED HOLES

Applying the 3D physics- mathematics models, the numerical analysis is performed for the air-side flow and heat transfer characteristics of rectangular-fin elliptic-tube, which are the fundamental element used in direct air-cooled power plant. The local heat transfer coefficients distributions on the surface of fins with and without interrupted holes were discussed under different velocities. The results indicate that it is the wake region behind the tube that weakens the heat transfer of tube fin. The influences of the dimension, number and position of interrupted holes to the finned-tube outside are also compared. Results show that the dimension has the obvious influence to the flow and heat transfer characteristics, while that of number and position is comparative small.