空气横掠平翅片管的换热与流动数值研究

Numerical Study of Flow and Heat Transfer of Air Across Rectangular Plate Fin-and-tube

对平直翅片管外不可压缩空气稳态、层流流动的传热与流动阻力特性进行了三维数值模拟,分析了入口流速以及管离翅片入口段的不同位置对流动与换热的影响,得到了阻力因数以及翅片和管壁面的平均努塞尔特数随雷诺数和管相对位置变化的关系曲线;给出了翅片的温度以及局部努塞尔特数的分布;并以翅片效率为目标函数,获得了6种不同管位置在不同雷诺数下的最佳结构型式,利用本文算法对参考文献的试验数据进行验证,模拟结果与试验数据吻合较好,验证了模型的可靠性和有效性。

The heat transfer and fluid flow resistance characteristics outside the tube of plate fin-and-tube heat exchanger were numerically simulated under steady,laminar flow for incompressible air. The effects of the inlet velocity and the tube center distance away from fin entrance on flow and heat transfer were analyzed,and the relation of the flow resistance coefficient and average Nusselt number (Nu) of the fin and tube surface with Reynolds number (Re) and the tube relative position were determined. Moreover,the distributions of the temperature and the local Nu on fin surface were displayed. The best structure type of the six different tube position was obtained for different Re by taking the fin efficiency as objective function. The reliability and validity of the model and algorithm were examined by comparison the simulation results with reference experimental data.