化工学报

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饱和气液相密度关联外推的新通用对比态方程

卿康1(), 汪尔奇1, 杨震1, 段远源1,2()   

  1. 1.清华大学热科学与动力工程教育部重点实验室,二氧化碳资源化利用与减排技术北京市重点实验室,北京 100084
    2.西南联合研究生院,云南 昆明 650092
  • 收稿日期:2025-11-13 修回日期:2026-01-07 出版日期:2026-01-08
  • 通讯作者: 段远源
  • 作者简介:卿康(2001—),男,博士研究生,qk23@mails.tsinghua.edu.cn
  • 基金资助:
    国家重点研发计划项目(2023YFB4102201);云南省西南联合研究生院科技专项基金资助项目(202302AO370018);清华大学-山西清洁能源研究院创新种子基金资助项目

New universal corresponding state equation for correlation and extrapolation of saturated vapor-liquid density

Kang QING1(), Erqi WANG1, Zhen YANG1, Yuanyuan DUAN1,2()   

  1. 1.Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Beijing Key Laboratory of CO2 Utilization and Reduction Technology, Tsinghua University, Beijing 100084, China
    2.Southwest United Graduate School, Kunming 650092, Yunnan, China
  • Received:2025-11-13 Revised:2026-01-07 Online:2026-01-08
  • Contact: Yuanyuan DUAN

摘要:

饱和密度是流体物质在气液相平衡时的重要热物性参数,在热力循环及化工过程中被广泛应用,但实验数据往往有限且离散,因此建立能够准确关联数据并能够可靠外推的饱和密度方程具有重要意义。基于饱和密度与饱和蒸气压的热力学特征相似性,此前提出的饱和蒸气压方程可推广至饱和密度,并以32种物质为对象与Zhang方程和Wagner型方程比较分析后证明,在关联性能上,新方程与Zhang方程和Wagner型方程偏差量级相当,足以在测量不确定度范围内关联实验数据;而在外推性能上,新方程总体优于Zhang方程和Wagner型方程,外推趋势更为稳定准确。如在外推拟合中将新方程部分参数固定后,外推趋势稳定性及准确性可进一步提升。

关键词: 热力学性质, 气液平衡, 模型, 预测, 饱和密度, Wagner型方程

Abstract:

Saturated density, a key thermophysical property of fluids at vapor–liquid equilibrium, is widely used in power cycles and chemical processes. However, experimental data of saturated density are often scarce and scattered; consequently, developing a correlation equation that accurately reproduces existing measurements while providing reliable extrapolation is essential. In this work, based on the thermodynamic similarity between saturated density and saturated vapor pressure, the previously proposed three-parameter saturated vapor pressure equation is extended to saturated density. The functional form is preserved, ensuring positive density and correct limiting behavior toward the critical point and triple point. Using thirty-two substances that possess abundant experimental data, the new equation is compared with the Zhang equation and Wagner equation. The results demonstrate that, with respect to correlation, the deviations of the new equation are of the same magnitude as those of the Zhang equation and Wagner equation and lie within the reported experimental uncertainties. In terms of extrapolation, the new equation is superior to or equivalent to the Zhang equation and Wagner equation, and the extrapolation trend is more stable and accurate. Furthermore, by fixing some parameters of the new equation in extrapolation fitting, the stability and accuracy of the extrapolation trend can be further improved, yielding a extrapolation that is both thermodynamically consistent and numerically sound.

Key words: thermodynamics properties, vapor–liquid equilibrium, model, prediction, saturated density, Wagner equation

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