Abstract This paper presents new experimental results of heat transfer coefficient and pressure drop measured during condensation of R1234ze(E) and R32 in a brazed aluminum multichannels test section with 1.6 mm hydraulic diameter at 40 °C saturation temperature, mass velocity from 55 to 275 kg m−2 s−1, heat flux up to 35 kW m−2 and a complete range of vapor quality. The test section displays parallel channels obtained through the bar-and-plate technology using perforated turbulators brazed to the aluminum plates. These are the first data of condensation in a similar geometry presented in the open literature. The measured heat transfer coefficients suggest that the condensation process is strongly affected by the surface tension effects in the whole range of operating conditions, while the effect of mass flux is very limited. This is related to the non-circular shape of the parallel minichannels. Condensation heat transfer has also been studied during flow of superheated vapor. The experimental data have been compared against prediction methods available in the literature. Fourteen models have been applied for the heat transfer coefficient, ten models have been applied for the pressure drop. Relevant suggestions are given for the design of condensers using such a technology.

中文翻译：

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低 GWP 制冷剂在棒板式换热器内冷凝过程中的传热和压降

摘要 本文介绍了 R1234ze(E) 和 R32 在水力直径为 1.6 mm 的钎焊铝多通道试验段在 40 °C 饱和温度、55 至 275 kg 质量速度下冷凝过程中测量的传热系数和压降的新实验结果。 m-2 s-1，高达 35 kW m-2 的热通量和完整的蒸汽质量范围。测试部分显示了通过棒板技术使用钎焊到铝板上的穿孔湍流器获得的平行通道。这些是公开文献中提出的类似几何形状的第一个冷凝数据。测得的传热系数表明，冷凝过程在整个操作条件范围内都受到表面张力效应的强烈影响，而质量通量的影响非常有限。这与平行微通道的非圆形形状有关。还研究了过热蒸汽流动期间的冷凝传热。已将实验数据与文献中可用的预测方法进行了比较。传热系数应用了十四个模型，压降应用了十个模型。对采用这种技术的冷凝器的设计提出了相关建议。