Abstract In this work, experiments were carried out to compare the phase separation performance of double branching T-junction with that of single branching T-junction. The inlet and outlet branches of double T-junction were arranged horizontally with the inner diameter of 8 mm. R134a was used as the working fluid. The inlet mass flow rate (mass flux) was set at 10, 15, 20, 25 g s−1 (199, 298, 398, 497 kg m−2 s−1) and the inlet quality was set at 0.3, 0.5, 0.7 respectively in the experiment of single T-junction. It is concluded that the inlet mass flux has little influence on phase separation while the phase separation efficiency drops sharply with the increase of inlet quality, which is consistent with the conclusions in literature. The experimental data is also compared with the predicted values generated by theoretical models based on air-water and it is found that there is no model suitable for refrigerants. Furthermore, a comparative study between single T-junction and double T-junction was carried out from two perspectives: separation performance comparison of different branches and comparison between single and double T-junctions. The results show that the double T-junction performance is greatly affected by inlet quality and mass split ratio of the first branch, and not always higher than that of single T-junction for horizontal arrangement. Finally, predicting equations of outlet quality of double T-junction are correlated based on experimental data, which have a high predicting accuracy under the high mass split ratio conditions.

中文翻译：

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单双T型接头相分离对比实验研究

摘要 在这项工作中，通过实验比较了双支化T 型接头与单支化T 型接头的相分离性能。双T型接头的进出口支管水平布置，内径为8mm。R134a用作工作流体。入口质量流量（质量通量）设置为 10、15、20、25 gs-1（199、298、398、497 kg m-2 s-1），入口质量设置为 0.3、0.5、0.7分别在单T型接头的实验中。结论是入口质量流量对相分离的影响很小，而随着入口质量的增加相分离效率急剧下降，这与文献中的结论是一致的。还将实验数据与基于空气-水的理论模型生成的预测值进行比较，发现没有适用于制冷剂的模型。并从不同支路的分离性能比较和单双T型接头的比较两个角度进行了单T型接头和双T型接头的对比研究。结果表明，双T型接头性能受第一支管入口质量和质量分流比影响较大，水平布置时并不总是高于单T型接头。最后，基于实验数据建立了双T型接头出口质量预测方程，在高质量分流比条件下具有较高的预测精度。