In present work, numerical simulation has been performed using the volume of fluid method under steady-state condition to find the effect of various operating parameters, viz. mass flux, vapor quality and effective thermal conductivity on heat transfer coefficient using refrigerants R1234ze and R1234yf. The numerical simulation has been carried out using various turbulence models, viz. the standard k − ε model, the standard k − ω model and the low-Re SST k − ω model. The model having minimum deviation with experimental results is considered for subsequent study. The hydraulic diameter and length of mini-channel considered are 1.085 and 420 mm, respectively. The vapor quality has been varied from 0.14 to 0.95, and mass flux has been varied from 200 to 800 kg/m² s keeping saturation temperature of 313 K. The heat transfer coefficient results of hydrofluoroolfine refrigerants R1234yf and R1234ze have been compared with hydrofluorocarbons refrigerant R134a in order to check the suitability of new hydrofluoroolfine refrigerants as a replacement to hydrofluorocarbons refrigerant. It has been observed from the flow regime map proposed by Sardesai et al. (Chem Eng Sci 36:1173–1180, 1981) that majority results of heat transfer coefficient for refrigerants R1234ze and R1234yf fall in the annular flow regime. It has been observed that the effective thermal conductivity may play vital role in the local heat transfer rate compared with the liquid film thickness.

在目前的工作中，已经在稳态条件下使用流体体积法进行了数值模拟，以发现各种运行参数的影响。使用制冷剂R1234ze和R1234yf的质量通量，蒸汽质量和有效的热导率，对传热系数的影响。已经使用各种湍流模型进行了数值模拟。标准k  -  ε模型，标准k  -  ω模型和low-Re SST k  -  ω模型。与实验结果具有最小偏差的模型被考虑用于后续研究。所考虑的小通道的水力直径和长度分别为1.085和420 mm。蒸气质量在0.14至0.95之间变化，质量通量在200至800 kg / m ^{2之间变化} 保持饱和温度为313K。将氢氟烃类制冷剂R1234yf和R1234ze与氢氟烃制冷剂R134a的传热系数结果进行了比较，以检查新型氢氟烃类制冷剂是否可以替代氢氟烃制冷剂。从Sardesai等人提出的流动状态图可以观察到。（Chem Eng Sci 36：1173-1180，1981），制冷剂R1234ze和R1234yf的传热系数的大多数结果都属于环形流动状态。已经观察到，与液膜厚度相比，有效的热导率可能在局部传热速率中起关键作用。