CIESC Journal ›› 2022, Vol. 73 ›› Issue (4): 1483-1492.DOI: 10.11949/0438-1157.20211690

• Thermodynamics • Previous Articles     Next Articles

A comparative and predictive study of the mixing rules for the vapor-liquid equilibria of CO2-based mixtures

Zirui WU1(),Rui SUN2,Lingfeng SHI1(),Hua TIAN2,Xuan WANG2,Gequn SHU1   

  1. 1.Department of Thermal Science and Energy Engineering, University of Science and Technology of China, Hefei 230027, Anhui, China
    2.State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China
  • Received:2021-11-26 Revised:2022-01-14 Online:2022-04-25 Published:2022-04-05
  • Contact: Lingfeng SHI

CO2混合工质的气液相平衡的混合规则对比与预测研究

吴子睿1(),孙瑞2,石凌峰1(),田华2,王轩2,舒歌群1   

  1. 1.中国科学技术大学热科学和能源工程系,安徽 合肥 230027
    2.天津大学内燃机燃烧学国家重点实验室,天津 300072
  • 通讯作者: 石凌峰
  • 作者简介:吴子睿(1997—),男,硕士研究生,wzr9717@mail.ustc.edu.cn
  • 基金资助:
    国家自然科学基金项目(51906237);中国科学技术大学青年创新重点基金(YD2090002008)

Abstract:

CO2 mixed working fluid has the characteristics of high efficiency and environmental friendliness, and has received extensive attention in the new generation of heat-power conversion cycle. Vapor-liquid equilibria properties for mixtures is the foundation of cycle analysis and calculation, so in order to improve the calculation accuracy of the vapor-liquid equilibria model for CO2-based mixtures, the vapor-liquid equilibria properties of seven CO2+HFCs/HFOs and four CO2+HCs mixtures are calculated by combining the PR equation of state with three mixing rules (vdW, WS, MHV1). The results show that the vdW mixing rule can achieve better results for CO2+HCs mixtures. For the CO2+HFCs/HFOs system, the calculation accuracy is similar in the subcritical region, but in the supercritical region, the WS mixing method improves the calculation accuracy obviously. MHV1 calculation accuracy is lower than WS and the calculation result of vdW is the most unsatisfactory. Finally, a differential model is proposed to predict the vapor-liquid equilibria properties of CO2-based mixtures. The predicted AARD(p) value is 2.03%, and the AAD(y) value is 0.0120, with high prediction accuracy.

Key words: CO2, mixtures, vapor-liquid equilibrium, PR equation of state, mixing rules, the difference model, prediction

摘要:

CO2混合工质兼顾高效和环境友好的特点,在新一代热功转化循环中受到广泛关注。混合工质气液相平衡性质是循环分析与计算的基础。为了提高CO2混合工质气液相平衡数据的计算精度,采用PR状态方程结合三种混合规则(vdW、MHV1、WS),对7种CO2+HFCs/HFOs及4种CO2+HCs混合工质的气液相平衡性质进行了计算。结果表明,对CO2+HCs混合工质,vdW混合规则可达较好的结果;对CO2+HFCs/HFOs混合工质,在亚临界区三者计算精度相近,但在超临界区,WS混合规则对计算精度提升明显。最后,提出了一种差值模型预测CO2混合工质气液相平衡性质,预测的AARD(p)值为2.03%,AAD(y)值为0.0120,预测精度较高。

关键词: CO2, 混合工质, 气液相平衡, PR状态方程, 混合规则, 差值模型, 预测

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