【摘要】 分子动力学模拟在揭示制冷剂微观特性、灵活控制工况、降低研究成本和提供预测性能方面具有明显优势，是研究制冷剂热物性的重要方法。基于分子动力学方法模拟不同混合比例R290/R170在蒸发低压工况以及冷凝高压工况范围内的密度和扩散系数，分析混合工质在蒸发和冷凝工况下的输运性质变化对制冷系统的影响。通过计算体系密度并进行模拟误差分析，混合制冷剂密度误差均值不超过5%,验证了模拟方法可行性。相同温压条件下，增加R170比例，混合制冷剂的密度减小，但实现气液相变的温度范围降低，相变温区分子活跃度增加，蒸发和冷凝工况下的扩散系数相应增加。因此，适当增加低沸点制冷剂比例可以改善低温系统蒸发温度与相变换热能力。采用分子动力学模拟的方法，对从微观角度分析混合工质制冷系统中热力优化的方向具有重要意义。更多还原

【Abstract】 Molecular dynamics simulation is an important method for studying the thermophysical properties of refrigerants. It offers significant advantages in revealing the microscopic characteristics of refrigerants, enabling flexible control of operating conditions, reducing study costs, and providing predictive performance. Based on the molecular dynamics method, the densities and diffusion coefficients of different mixing ratios of R290/R170 were investigated numerically in the range of low-pressure evaporating and high-pressure condensing conditions. Simultaneously, the influence of the changes in the transport properties of the mixed refrigerants on the refrigeration system under above conditions was analyzed. The average density error is less than 5% for mixed refrigerants by calculating the multiple densities and analyzing the simulation deviations, which verifies the feasibility of the simulation method. Increasing the proportion of R170 results in reducing densities of mixed refrigerants under the same temperature and pressure conditions. However, the temperature range for realizing the gas-liquid phase transition decreases, the molecular activity in the temperature zone of the phase transition increases, and the diffusion coefficient under the evaporation and condensation conditions increases accordingly. Therefore, an appropriate increase in the proportion of low-temperature boiling refrigerant can improve the evaporation temperature and phase change heat transfer capability of cryogenic systems. The method of molecular dynamics simulation is of great significance for analyzing the direction of thermal optimization in mixed refrigerants refrigeration systems from a microscopic point of view.更多还原