椭圆形和圆形翅片管流动与传热的数值研究

NUMERICAL STUDY ON FLOW AND HEAT TRANSFER IN A ELLIPTICAL AND CIRCULAR FINNED TUBE

对椭圆管椭圆翅片间的流动与传热规律进行了三维数值研究,分析了不同翅片间距、迎面风速对表面换热系数和流动阻力的影响;与具有相同结构参数(相同的基管当量直径和翅片厚度、表面积)的圆管圆翅片进行比较表明,在相同条件下,两者的表面换热系数相差不大,但椭圆管椭圆翅片间流动阻力却有明显的减小。场协同分析表明,翅片迎风侧的换热要优于背风侧;通过适当增加迎风侧翅片面积,减小背风侧翅片面积,可以在强化换热的同时,减小流动阻力。

A three-dimensional numerical simulation was carried out to study the flow and heat transfer characters outside the elliptical finned elliptical tube. The influence of fin parameters and inlet flow velocity on heat transfer coefficient and flowed friction was researched. With comparison of the circular finned circular tube which has the identical structure parameters （equivalent diameter, thickness of fin and the surface area）, in the identical condition, the heat transfer coefficients of elliptical tube and circular tube nearly are less different, but the flowed friction of elliptical tube reduced obviously. With the theory of field synergy, it was found that the local heat transfer on the fin located on the windward side is better than that on the leeward side. With the fin area increasing on the windward side and reducing that on the leeward side properly, the heat transfer could be enhanced, and at the same time, the flowed friction could be reduced.