当饱和蒸汽在由外部流体冷却的管中流动时，一些蒸汽在管壁上冷凝并形成液膜。制冷剂和其他低电导率流体的主要传热阻力是通过冷凝膜传导的阻力。在直管中有两种不同的冷凝机理:层流膜冷凝和强制对流冷凝。在这项研究中，动量和传热类比应用于环形流模型，使用冯·卡曼普遍速度分布来描述液膜。由于汽芯非常湍流，径向温度梯度被忽略，汽芯和液气界面的温度被假定为等于饱和温度。轴向热传导和液膜过冷也被忽略。 通过对传热方程进行数量级分析和无量纲化，得出了局部传热系数的简单公式。将分析结果与Rl2和R22的实验数据进行比较，并将结果用于证实一般设计方程）。用于强制对流冷凝。引文:伊利诺伊州芝加哥ASHRAE Transactions第79卷第1部分

When saturated vapor flows in a tube that is cooled by an exterior fluid, some of the vapor condenses on the tube wall and forms a liquid film. The main resistance to heat transfer for refrigerants and other low conductivity fluids is the resistance to conduction through the condensated film. There are essentially two different mechanisms of condensation in straight tubes: laminar film condensation and forced-convection condensation.In this investigation the momentum and heat transfer analogy was applied to an annular flow model using the von Karman universal velocity distribution to describe the liquid film. Since the vapor core is very turbulent, radial temp gradients were neglected, and the temperatures in the vapor core and at the liquid-vapor interface were assumed to be equal to the saturation temp. Axial heat conduction and subcooling of the liquid film were also neglected. An order of magnitude analysis and non-dimensionalization of the heat transfer equations resulted in a simple formulation for the local heat transfer coefficient. The analysis was compared to expemnental data for Rl2 and R22, and the results were used to substantiate a general design equation). for forced-convection condensation.