Condensation heat and mass transfer characteristics of low GWP zeotropic refrigerant mixtures R1234yf/R32 (mass fractions of 0.52:0.48 and 0.77:0.23, respectively) inside a horizontal smooth tube (inner diameter 4 mm) were studied experimentally. Moreover, a non-equilibrium film heat and mass transfer model was also developed by considering the mass transfer resistance on the vapor and the liquid side. Effects of mass flux, vapor quality, thermophysical properties and mass fraction on the heat transfer coefficients (HTCs) were analyzed. The heat transfer characteristics, especially the heat transfer deterioration caused by the mass transfer difference of the zeotropic refrigerant mixture, were evaluated. The experiment data show the HTCs of R1234yf/R32 (0.48:0.52) are lower than that of R1234yf at the inlet nearby of the condenser, then that becomes higher gradually than R1234yf due to mass transfer resistance decreasing. The non-equilibrium film model shows good agreement with the experimental results with the mean deviation in HTC of 22.9% at a mass fraction of 0.77:0.23 and 17.8% at a mass fraction of 0.48:0.52. Furthermore, the heat transfer degradation coefficient, interface temperature, diffusion flux of R32 and mass transfer Nusselt number were also reasonably determined with the non-equilibrium film model.

对水平光滑管（内径 4 mm）内的低 GWP 共沸制冷剂混合物 R1234yf/R32（质量分数分别为 0.52:0.48 和 0.77:0.23）的冷凝传热和传质特性进行了实验研究。此外，通过考虑蒸汽和液体侧的传质阻力，还开发了非平衡膜传热和传质模型。分析了质量通量、蒸汽质量、热物理性质和质量分数对传热系数 (HTC) 的影响。评估了传热特性，特别是由共沸混合制冷剂的传质差异引起的传热劣化。实验数据表明，在靠近冷凝器的入口处，R1234yf/R32（0.48:0.52）的HTCs低于R1234yf，然后由于传质阻力的降低而逐渐高于 R1234yf。非平衡膜模型与实验结果非常吻合，质量分数为 0.77:0.23 时 HTC 的平均偏差为 22.9%，质量分数为 0.48:0.52 时为 17.8%。此外，还利用非平衡膜模型合理确定了传热退化系数、界面温度、R32的扩散通量和传质努塞尔数。