低温固定点氩的分子力场参数模拟优化方法  

Simulation and Optimization of Molecular Force Field Parametersfor Low-Temperature Fixed Point Argon

作　　者：贾会伦 刘思琦 张海洋 高波[1,2,3] JIA Huilun;LIU Siqi;ZHANG Haiyang;GAO Bo(State Key Laboratory of Cryogenic Science and Technology,Technical Institute of Physics and Chemistry,Chinese Academy of Sciences,Beijing 100190,China;TIPC-LNE Joint Laboratory on Cryogenic Metrology Science and Technology,Technical Institute of Physics and Chemistry,Chinese Academy of Sciences,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing 100490,China;School of Metallurgy,Northeastern University,Shenyang 110819,China)

机构地区：[1]中国科学院理化技术研究所低温科学与技术全国重点实验室,北京100190 [2]中国科学院理化技术研究所中法低温计量科学与技术国际联合实验室,北京100190 [3]中国科学院大学,北京100049 [4]东北大学冶金学院,沈阳110819

出　　处：《西安交通大学学报》2025年第5期107-119,共13页Journal of Xi'an Jiaotong University

基　　金：国家重点研发计划资助项目(2022YFE0116100);国家自然科学基金资助项目(52125602);中国科学院青年创新促进会资助项目(2022028)。

摘　　要：为解决分子力场势能函数中分子间相互作用的Lennard-Jones参数难以准确求取的问题,以1990年国际温标所定义的低温固定点工质氩为例,提出一种基于势能参数-临界特性量效规律的分子力场Lennard-Jones参数优化方法。基于吉布斯系综蒙特卡罗方法,利用Trappe-ua和COMPASS两种力场对氩的气液相平衡开展了分子模拟研究,得到初步模拟结果。通过参数扰动法进行两势能参数对饱和气液相密度、饱和蒸气压和蒸发焓影响的定性分析,进一步通过定量分析构建了COMPASS力场势能参数与临界特性间的函数关系,将实验临界值代入确定了优化的COMPASS力场的Lennard-Jones参数。利用优化的参数重新编写力场进行模拟验证。结果表明,对于COMPASS力场而言,氩的饱和气液相密度、蒸气压及蒸发焓模拟精度显著提升,与Refprop 9.1软件计算值的平均绝对相对偏差由27%降到了18%,可为低温区其他固定点工质气液相平衡的分子力场Lennard-Jones参数优化提供参考。To address the challenge of accurately determining the Lennard-Jones parameters for intermolecular interactions in the potential energy function of molecular force fields,argon,a low-temperature fixed-point working substance defined by the 1990 International Temperature Scale,was taken as an example to propose a molecular force field Lennard-Jones parameter optimization method based on the potential energy parameter-critical property quantity efficiency rule.Initially,molecular simulation studies on the vapor-liquid phase equilibrium of argon were conducted using the Trappe-ua and COMPASS force fields based on the Gibbs ensemble Monte Carlo method,yielding preliminary simulation results.Subsequently,a qualitative analysis was carried out to determine the impact of two potential energy parameters on the saturated vapor-liquid phase density,saturated vapor pressure,and evaporation enthalpy with the parameter perturbation method.In addition,a quantitative analysis was also carried out to establish the functional relationship between the COMPASS force field potential energy parameters and critical properties,and the optimized Lennard-Jones parameters of the COMPASS force field were determined by substituting experimental critical values.Finally,the optimized parameters were used to reprogram the force field for simulation verification.As revealed by the results,for the Compass force field,the average absolute relative deviation of the simulated values of saturated vapor-liquid phase density,vapor pressure,and evaporation enthalpy of argon from the values calculated by the Refprop 9.1 software decreased from^(2)7%to 18%,indicating a significant improvement in simulation accuracy.The method proposed in this study can provide a reference for the optimization of Lennard-Jones parameters for vapor-liquid phase equilibrium of other fixed-point working fluids in the low-temperature region.

关 键 词：氩 低温固定点 气液相平衡 吉布斯系综蒙特卡罗方法 

分 类 号：TK121[动力工程及工程热物理—工程热物理]