几种环形翅片管通道内流体流动与换热特性的对比研究

Comparative Study on Fluid Flow and Heat Transfer Performance in the Channel of Annular Finned Tube

采用Fluent软件,对基管相同的圆翅片管和5种椭圆翅片管用稳态RNGκ-ε模型进行三维数值模拟,5种椭圆翅片管A_(fin),A_(min),D_e,P_(er),β分别与圆翅片(C_(ir))有相同的翅片面积、最小截面面积、翅片当量直径、翅片周长和翅化比.通过对不同雷诺数(Re)下流场及翅片表面局部努塞尔数(Nu)的分析比较,得到翅片管通道内流体流动及换热的特征,并提供了圆翅片管和5种椭圆翅片管的综合换热性能Nu/f的结果.研究表明,圆翅片C_(ir)的Nu大于椭圆翅片A_(fin),D_e,P_(er),β,但小于椭圆翅片A_(min).圆翅片的阻力系数f大于椭圆翅片A_(fin),P_(er),β的f,且小于椭圆翅片A_(min)的f.椭圆翅片D_e在Re较小(Re≤8 000)时与圆翅片C_(ir)的f的差值较小,在Re较大(Re>8 000)时与圆翅片C_(ir)基本相同.椭圆翅片A_(min)的综合换热效果最好.

The three dimensional numerical simulation of circular finned tube and 5 kinds of elliptical fin tube is performed with the steady state RNGκ-ε model by the Fluent software.The base pipes of the circular finned tube and five elliptical finned tubes are same.Fluid field and local Nusselt number on fin surface are analyzed and compared for different Reynolds numbers（Re）to obtain fluid flow and heat transfer characteristics in the channel of annular finned tube,and the result of comprehensive heat transfer coefficient（Nu/f）on a circular finned tube and 5 elliptical finned tubes is also provided.The results show that the Nuof circular fin is biggest among elliptical fin A（fin）,elliptical fin De,elliptical fin P（er）and elliptical finβ,but it is smaller than elliptical fin A（min）.The flow resistance coefficient of circular fin is biggest among elliptical fin A（fin）,elliptical fin P（er）and elliptical finβ,but it is smaller than elliptical fin A（min）.The results of Thermal Resistance is contrary to Nusselts.The difference of flow resistance coefficient between elliptical fin De,and the circular fin is small when the Reynolds is smaller（Re≤8 000）,while flow resistance coefficient of elliptical fin Deis basically same with circular fin when the Reynolds is larger（Re〉8 000）.The combined heat transfer effect of elliptical fin A（min）is the best.