As the working fluid of energy transfer and conversion, refrigerants are essential in refrigeration and power systems.

In order to improve the efficiency in power system, and reduce the design cost of evaporator, it is important to reveal the evaporation mechanism of refrigerants. In this study, the evaporation of R600 (butane), R134a (1,1,1,2-tetrafluoroethane), R32 (difluoromethane), and R1234yf (2,3,3,3-tetrafluoro-1-propene) was studied using molecular dynamics simulations. The internal fields such as density, radial mass fluxes of the molecular systems during the evaporation are compared. Besides, the prediction accuracy of the traditional diffusion-based model was evaluated. The results show that the prediction accuracy of traditional diffusion-based model is low due to the vapor thermal conductivity affected by the scale effect. A modified model based on vapor thermal conductivity with rarefied gas effect and interfacial influence is proposed to significantly improve the calculation accuracy for nanodroplet evaporation of different refrigerants. The evaporation rates of different refrigerants are affected by the molecular number density and molecular diffusion in the vapor phase near the interfacial region. The larger the molecular number density and the molecular self-diffusion coefficient are, the faster the droplet evaporation rate is.

作为能量传递和转换的工作流体，制冷剂在制冷和电力系统中必不可少。

为了提高电力系统的效率，降低蒸发器的设计成本，揭示制冷剂的蒸发机理很重要。在这项研究中，研究了R600（丁烷），R134a（1,1,1,2-四氟乙烷），R32（二氟甲烷）和R1234yf（2,3,3,3-四氟-1-丙烯）的蒸发分子动力学模拟。比较蒸发期间分子系统的内部场，例如密度，径向质量通量。此外，还评估了传统基于扩散的模型的预测准确性。结果表明，由于尺度效应影响了蒸汽的热导率，传统的基于扩散的模型的预测精度较低。提出了一种基于蒸汽热导率的稀有气体效应和界面影响的修正模型，以显着提高不同制冷剂的纳米液滴蒸发的计算精度。不同制冷剂的蒸发速率受界面区域附近气相中的分子数密度和分子扩散影响。分子数密度和分子自扩散系数越大，液滴的蒸发速度越快。