微圆管内环状流凝结换热特性的数值模拟

NUMERICAL SIMULATION FOR CONDENSATION HEAT TRANSFER CHARACTERISTICS WITH ANNULAR FLOW IN MICROTUBE

本文提出了微圆管内环状流凝结换热的分析模型,考虑了重力、汽液界面剪切力、表面张力以及界面凝结热阻的作用。文中主要研究凝结换热过程中重力、入口蒸汽Re数及外壁面温度的影响。模拟的结果表明,重力对微圆管流动凝结换热的影响非常小,可被忽略;凝结液的排除主要依赖于汽液界面的剪切应力作用,使Nu随蒸汽进口Re数的增加而明显增大;冷却外壁面的温度对凝结换热也具有一定的影响, Nu将随外壁面温度的降低而增大。

Considering gravity, interfacial shear stress, surface tension and interfacial thermal resistance, the analysis model for annular flow condensation heat transfer in microtube was presented. The effect of gravity, inlet steam Re and outside wall temperature was the research emphasis in this article. From the simulated result, gravity had so little effect on flow condensation heat transfer in microtube that it could be neglected. The exclusion of condensate was mainly depended on interfacial shear stress, so Nu increased obviously with increasing inlet steam Re. Outside wall temperature had certain effect on condensation heat transfer, and Nu increased with decreasing outside wall temperature.