超临界压力下CO_2流体的性质研究Study on the Properties of CO_2 Fluid at Supercritical Pressure
杨俊兰,马一太,曾宪阳,刘圣春
YANG Jun-lan1,2,MA Yi-tai1,ZENG Xian-yang1
摘要(Abstract)：
为了全面了解CO2在气体冷却器中的流动及传热特性以及为设计高效气体冷却器提供理论基础,对超临界CO2流体的性质进行了深入的研究,在三维图上分析了温度和压力对超临界CO2热物理性质的影响,并对超临界CO2流体进行了微观分析。结果表明,CO2的比热、密度、导热系数以及粘度在准临界点附近的变化非常剧烈。针对CO2比热的变化特点,得到了准临界温度的计算关联式,并给出了准临界区定义。CO2的密度、导热系数以及粘度变化最大时的温度与准临界温度相当接近。微观分析表明,超临界CO2流体分子间的作用力比较小,分子在临界区附近的聚集行为特别显著,这可以用来解释近临界区CO2物性独特的原因所在。
In order to understand the flow and heat transfer characteristics of CO2 fluid in the gas cooler and provide indispensable theoretical basis for designing high efficiency gas cooler,the properties of supercritical CO2 fluid are studied thoroughly.The effect of temperature and pressure on the thermo-physical properties of supercritical carbon dioxide are theoretically analyzed in the three dimensional graphs.Also the properties of supercritical CO2 fluid are analyzed by microcosmic.The results show that CO2 specific heat,density,thermal conductivity and viscosity vary abruptly near the pseudocritical temperature.According to the characteristics of CO2 specific heat,the correlations of the pseudocritical temperature are obtained and the pseudocritical region is defined.It is also found that the temperatures at which the CO2 density,thermal conductivity and viscosity possesses the maximum change are very closer to the pseudocritical temperature.The microcosmic analysis shows that the applied force between the supercritical CO2 molecular is relatively small.The molecular aggregation behavior near the critical region is very obvious,which is the main reason for the unique CO2 properties near the critical region.
关键词(KeyWords)：
超临界CO2;热物理性质;准临界温度;准临界区;分子聚集
supercritical CO2;thermo-physical properties;pseudocritical temperature;pseudocritical region;molecular aggregates
基金项目(Foundation): 国家自然科学基金项目(50506019);; 天津市自然科学基金项目(06YFJMJC05400)
作者(Author):
杨俊兰,马一太,曾宪阳,刘圣春
YANG Jun-lan1,2,MA Yi-tai1,ZENG Xian-yang1
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