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采用层流和紊流两种模型对一水平管外垂下液膜的强制对流蒸发换热性能进行了数值计算．对管顶部的冲击滞止区和管侧部的自由绕流区分别采用不同的坐标变换方法进行微分方程组简化．根据滞止区计算结果确定自由绕流区的初始边界条件，排除了以前类似计算中人为假定计算边界条件的缺陷．紊流计算采用壁面函数法．数值计算结果确认了液膜蒸发量对换热系数的影响可以忽略，液膜内温度分布不能近似为线性分布．计算结果和作者的实验数据及其他研究的实验数据进行了比较，实验值处于层流解和紊流解之间，更靠近紊流解．对水和Ｒ１１两种工质，紊流解和实验值吻合得很好
The laminar flow and turbulent flow models are used to calculate the forced convective heat transfer performance of a liquid film suspended from a horizontal tube. Different coordinate transformation methods were used to simplify the differential equations for the free flow around the impact stagnation zone and the tube side at the top of the pipe. The initial boundary conditions of the free-flow area are determined according to the calculation results of the stagnation zone, and the defects of artificial assumption of boundary conditions in the similar calculation are excluded. Turbulence calculation using the wall function method. The numerical results confirm that the influence of liquid film evaporation on the heat transfer coefficient can be neglected, and the temperature distribution in the liquid film can not be approximated as a linear distribution. The calculated results are compared with the experimental data of the authors and the experimental data of other studies. The experimental data lie between the laminar and turbulent solutions and closer to the turbulent solution. On the water and R11 two working fluid, turbulent solution and the experimental values are in good agreement