| 超临界二氧化碳类液-类气区边界线数值分析 |
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| 引用本文： | 孙辉,刘婧楠,章立新,杨其国,高明. 超临界二氧化碳类液-类气区边界线数值分析[J]. 物理学报, 2022, 0(4) |
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| 作者姓名： | 孙辉 刘婧楠 章立新 杨其国 高明 |
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| 作者单位： | 上海理工大学能源与动力工程学院;上海市动力工程多相流动与传热重点实验室 |
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| 基金项目： | 国家自然科学基金(批准号:51976127);上海市地方高校能力建设项目(批准号:20060502000)资助的课题。 |
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| 摘 要： | 超临界二氧化碳(S-CO2)因在萃取、沉淀、热力循环及化学反应等方面有着十分广阔的应用前景,逐渐成为学术界的重要研究课题.由于在近临界区,可以观察到随温度或压力变化出现大量的物性异变现象,使得各国学者对流体临界点附近区域的研究产生了浓厚兴趣.随着分子动力学模拟技术的快速发展,该技术可辅助传统实验方法用于研究近临界流体的相关物性.为确定S-CO2在近临界区Widom线范围及类液-类气区的分子结构特征,本文通过分子动力学模拟技术结合聚类分析,研究了温度和压力范围分别在300—350 K和5.5—18.5 MPa下,CO2密度时间序列变异系数及偏度同Widom线和类液-类气区间的关系.结果表明:S-CO2在近临界区Widom线的确定可通过连接密度时间序列曲线变异系数极大值点来确定,Widom线沿着临界点开始延伸直到350 K时停止;S-CO2类液区和类气区的分子分布结构可以用数密度分布的偏度来区分,偏度在类气态时为正值,在类液态时为负值,而在Widom线上达到最大值.
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| 关 键 词： | 分子动力学 超临界二氧化碳 Widom线 类液-类气区 |
Numerical analysis of boundary line between liquid-like zone and gas-like zone of supercritical CO2 |
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| Sun Hui,Liu Jing-Nan,Zhang Li-Xin,Yang Qi-Guo,Gao Ming. Numerical analysis of boundary line between liquid-like zone and gas-like zone of supercritical CO2[J]. Acta Physica Sinica, 2022, 0(4) |
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| Authors: | Sun Hui Liu Jing-Nan Zhang Li-Xin Yang Qi-Guo Gao Ming |
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| Affiliation: | (School of Energy and Power Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China;Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering,Shanghai 200093,China) |
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| Abstract: | Supercritical carbon dioxide has gradually been becoming an important research subject in the academic field due to the fact that it has a promising application prospect in the field of extraction,precipitation,thermodynamic cycle and chemical reaction.In recent years,the interest in studying the region near the critical point was aroused and a large variation of the physical properties could be detected due to the change of temperature and pressure.The rapid development of molecular simulation technology benefits the traditional experimental methods to study the variations of relevant physical properties in the near-critical region.In order to find out the Widom line range of supercritical carbon dioxide in the near-critical region and the molecular structure characteristics of the liquid-like gas region,both the molecular dynamics simulation technology and the cluster analysis are used to investigate the relation between variation coefficient and skewness of CO2 density time series with Widom line and liquid-gas-like interval,under the condition of the temperature and pressure range of 300–350 K and 5.5–18.5 MPa,respectively.The results show that the Widom line of supercritical carbon dioxide in the near-critical region can be determined by connecting the maximum coefficient of variation of the density time series curve.The Widom line begins to extend along with the critical point until it stops at 350 K.The molecular distribution structure of supercritical carbon dioxide liquid-like region and gas-like region can be differentiated by the skewness of the number density distributions.The skewness is positive in the gas-like region,but negative in the liquid-like region,and reaches the maximum at the Widom line. |
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| Keywords: | molecular dynamics supercritical carbon dioxide widom line liquid-gas like region |
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