当冷凝发生在蒸汽速度较高的水平管内时，冷凝液在管壁上呈环形流动，蒸汽在管芯中流动。许多研究人员对这个问题进行了实验和分析研究。涉及无量纲组的经验相关性不太成功，因为相关性不包括所有流量变量（参考文献1、2、3、4、5）。Carpenter和Colburn（6）只考虑了凝结水流的层流子层，并推导了一个带有经验常数的方程。 后来的研究人员对该方法进行了修改。（7,8）对于小范围的普朗特数，该方程与经验数据吻合良好。但该方程没有普遍适用性。Rohsenow、Webber和Ling（9）分析了竖板上的液膜，并通过传热和动量传递类比得出了传热系数。类似的方法出现在后来的论文中。（10,11）本文将进一步发展这种方法，用于环形流型。引文:ASHRAE交易，第77卷，第2部分，华盛顿特区

When condensation takes place inside a horizontal tube with high vapor velocity, condensate flows in an annular shape on the tube wall and vapor flows in the core.Many investigators have studied this subject both experimentally and analytically. Empirical correlations involving non-dimensional groups were not quite successful because the correlations did not include all the flow variables (Refs 1, 2, 3, 4, 5). Carpenter and Colburn (6) considered only the laminar sublayer of condensate flow and derived an equation with an empirical constant. This method was modified by later investigators.(7,8) For a small range of the Prandtl Number, this equation gives good agreement with empirical data. But the equation has no general applicability. Rohsenow, Webber and Ling(9) analyzed the liquid film on the vertical plate and the heat transfer coefficient was obtained by the heat and momentum transfer analogy. A similar approach appeared in later papers.(10,11) This method will be developed further for the annular flow regime in this paper.