含R1234yf混合工质汽液相平衡的混合规则评估与预测研究

Evaluation and predictive study of the mixing rules for vapor-liquid equilibrium of R1234yf mixtures

含R1234yf混合工质具有系统性能优良且对环境友好的特点,在当前制冷剂迭代中受到了广泛关注。汽液相平衡性质是混合工质的基础热物理性质,其理论计算至关重要。为提高含R1234yf混合工质汽液相平衡数据的计算精度,选取PR状态方程结合vdW、WS、MHV1三种混合规则和NRTL活度系数模型评估了16种含R1234yf二元混合工质的汽液相平衡性质。结果表明,WS混合规则和MHV1混合规则计算性能优于vdW混合规则;vdW混合规则对大多数混合工质计算性能较好。最后提出一种预测模型预测含R1234yf混合工质汽液相平衡性质,预测的相对压力偏差值为0.49%,气相摩尔分数绝对偏差值为0.0031,预测偏差满足工程应用。

The mixed refrigerant containing R1234yf has the characteristics of excellent system performance and environmental friendliness,and has received widespread attention in the current iteration of refrigerants.The vaporliquid equilibrium is the most basic thermodynamic property for the mixtures,and its theoretical calculation is of vital importance.To enhance the accuracy of vapor-liquid equilibrium data for the R1234yf mixtures,the Peng−Robinson(PR)equation of state coupling with three mixing rules(vdW,WS,and MHV1),and the NRTL activity coefficient model are selected to evaluate the experimental properties of vapor-liquid equilibrium for 16 R1234yf binary systems.The results show that the calculation performance of WS mixing rules and MHV1 mixing rules is better than that of vdW mixing rules.The vdW mixing rule provides superior computational performance for the majority of mixtures.Finally,a predictive model is proposed to forecast the vapor-liquid equilibrium properties of R1234yf-based mixtures.The predicted AARD of pressure is 0.49%and the AAD of mole fraction of gas phase is 0.0031.These predictive deviations satisfy engineering applications.