跨临界时二氧化碳体系微观结构特征的分子动力学模拟  

Molecular Dynamics Simulation on Microscopic Characteristics of Carbon Dioxide in Trans-Critical Progress

作　　者：唐佳 黄彦平[1] 王俊峰[1] 臧金光[1] 刘光旭[1] 刘睿龙 Tang Jia;Huang Yanping;Wang Junfeng;Zang Jinguang;Liu Guangxu;Liu Ruilong(CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology,Nuclear Power Institute of China,Chengdu,610213,China)

机构地区：[1]中国核动力研究设计院中核核反应堆热工水力技术重点实验室,成都610213

出　　处：《核动力工程》2021年第4期14-20,共7页Nuclear Power Engineering

基　　金：国家自然科学基金核技术创新联合基金项目(U1867218)。

摘　　要：应用分子动力学模拟方法研究了跨越临界点时二氧化碳体系微观结构特性。径向分布函数的分析表明,临界点前后体系内短程序结构变化很小,主要受分子间极强的近邻相互作用的强化效果影响,第一近邻配位数的分析进一步显示近程结构的变化以配对分子数量的变化为主;气态条件下的二氧化碳体系仍呈"近程有序且长程无序"状态;静态结构因子的分析表明,拟临界区体系中存在中远程有序结构;定义了无序距离,该参数的突增表明了临界点附近分子间相互作用距离剧烈增大。Molecular dynamics(MD)simulations was performed to analyze the microscopic characteristics of carbon dioxide in trans-critical progress.Radial distribution function(RDF)analysis exhibited that the short-range structure varied weakly near the critical point,which was mainly enhanced by the strong neighbor intermolecular interaction.The simulation results of the coordination number in first shell further show that the variation of short-range structure primarily lies in the number change of coordinated molecular;The gaseous CO_(2) is still of an ordered structure in the short-range and of a disordered structure in the long-range;The static structure factor analysis showed the existence of medium/long-rang ordered structure.Disorder range was defined and its abrupt surge showed explicitly that the range of intermolecular interaction increased in the pseudo-critical region.

关 键 词：超临界二氧化碳 跨临界 微观特性 分子动力学模拟 

分 类 号：TL339[核科学技术—核技术及应用] O552[理学—热学与物质分子运动论]