Nucleate pool boiling heat transfer of R1234ze(E), R1233zd(E) and R134a were investigated outside two reentrant cavity tubes. The two tubes have different fin density while the size of subsurface tunnel width and fin height are almost the same. In the experiment, the pool boiling heat transfer is tested at the saturation temperature of 6 °C and heat flux of 10–80 kW/m². A brief summary of pool boiling experimental data of Hydrofluoroolefins(HFO) refrigerants on different enhanced tubes from recent work is also provided. It is found that the combinations of tube and refrigerant: R134a and R13234ze(E) outside Tube-B1 shows almost equivalent boiling heat transfer performance. The two combinations also yield the highest averaged overall heat transfer coefficient. At the lower heat flux less than 60 kW/m², for the tube with larger fin density and thinner fin thickness, the number of nucleation cavities is found to be more than that with larger fin thickness. At the heat flux more than 40 kW/m², the boiling heat transfer coefficient of R134a and R1234ze(E) for the two enhanced tubes nearly merges into a single curve. At the higher heat flux, boiling heat transfer shows weak dependence on the surface structures. The boiling heat transfer coefficient of R1233zd(E) is more than 40 percentages lower than R134a for the two tubes at the nearly identical conditions. The research is helpful for the designer to summarize the boiling heat transfer performance of some typical HFO refrigerants.

在两个凹腔管外研究了R1234ze（E），R1233zd（E）和R134a的核池沸腾传热。两条管的翅片密度不同，而地下隧道宽度和翅片高度的大小几乎相同。在实验中，在饱和温度6°C和热通量10-80 kW / m ²下测试了池沸腾传热。还简要总结了近期工作中不同增强管上的氢氟烯烃（HFO）制冷剂的池沸腾实验数据。发现管和制冷剂的组合：在管B1外部的R134a和R13234ze（E）表现出几乎相等的沸腾传热性能。两种组合还产生最高的平均总传热系数。在较低的热通量下小于60 kW / m^{如图2所示}，对于翅片密度较大且翅片厚度较薄的管，成核腔的数量多于翅片厚度较大的管。当热通量大于40 kW / m ^2时，两个增强管的R134a和R1234ze（E）的沸腾传热系数几乎合并为一条曲线。在较高的热通量下，沸腾传热对表面结构的依赖性较弱。在几乎相同的条件下，两管的R1233zd（E）沸腾传热系数比R134a低40％以上。该研究有助于设计人员总结一些典型的HFO制冷剂的沸腾传热性能。