水平椭圆绕线管外的凝结换热研究

Condensation on Horizontal Wired Elliptical Tubes

本文得到了椭圆绕线管外局部及平均凝结换热Nusselt数的变化规律,分析了椭圆的几何参数、绕线参数及表面张力等因素对换热的影响,并将结果与圆管情况进行了比较.在A=1～8范围内,当e=0～0.9209时,绕线管与光管比较,冷凝效果高29%～109%左右.理论分析与实验结果相结合,得到了凝结换热无因次关系式和式中的经验常数,确定了最佳绕线参数.

Condensation heat transfer from the external surface of horizontally pla red wired elliptical tubes was studied both theoretically and experimentally. The numerical solutions for local and average condensation Nusselt numbers Nu () and Nu were presented for a number of the values of parameters , e. A and were compared with classical solutions in a special case (circular smooth tube: e=0, A=0). The general non-dimensional formulae for condensation heat transfer were obtained and the empirical constants and optimum wiring parameters were proposed.