基于不同势函数的正构烷烃物理性质分子动力学模拟  

Molecular Dynamics Simulation of Physical Properties of n-Alkane Based on Different Potential Models

作　　者：陈飞龙 张延志 何志霞 Chen Feilong;Zhang Yanzhi;He Zhixia(School of Energy and Power,Dalian University of Technology,Dalian 116024,China;Institute for Energy Research,Jiangsu University,Zhenjiang 212013,China)

机构地区：[1]大连理工大学能源与动力学院,大连116024 [2]江苏大学能源研究院,镇江212013

出　　处：《燃烧科学与技术》2023年第4期451-459,共9页Journal of Combustion Science and Technology

基　　金：国家自然科学基金资助项目(52106154);江苏省自然科学基金资助项目(BK20190855).

摘　　要：采用分子动力学模拟详细比较了4种常用势函数对正构烷烃物理性质预测精度的影响,提出了一种新的修正力场并对其进行广泛的验证,验证主要包括饱和两相密度、饱和蒸气压和自扩散系数等热物理和输运性质.之后,将改进力场应用于二元组分燃料热物性研究中,探究了不同混合比例条件下通过每种组分加权平均的方法估算混合物饱和热物性的准确度.研究发现,改进力场对正庚烷和正十二烷物理性质的预测与实验值较为吻合;在温度较低、正庚烷摩尔分数较高或者温度较高、正庚烷摩尔分数较低的工况下,通过加权平均得到的饱和物性值较为准确.In this paper,molecular dynamics simulation was used to compare in detail the effect of four com-monly used potential models on the prediction accuracy of the physical properties of n-alkane,and a new modified model was proposed and extensively validated,which mainly includes the thermophysical and transport properties such as saturated two-phase density,saturated vapor pressure and self-diffusion coefficient.After that,the modified potential model was applied to the study of the thermophysical properties of binary-component fuels,and the accuracy of estimating the saturated physical properties of the mixture by the weighted average method of each component at different mixing ratios was explored.It was found that the predictions from the modified model show good agreement with the measurements for n-heptane and n-dodecane.When the temperature is lower and the mole fraction of n-heptane is higher,or when the temperature is higher and the mole fraction of n-heptane is lower,the saturated physical property value obtained by the weighted average is more accurate.

关 键 词：分子动力学模拟 物理性质 势函数 二元组分 

分 类 号：TK401[动力工程及工程热物理—动力机械及工程]