双原子氧气液界面特性的分子动力学模拟  

Molecular dynamics simulation of gas-liquid interface characteristics for diatomic oxygen

作　　者：毛志红[1] 包福兵[1] 余霞[1] 

机构地区：[1]中国计量学院计量测试工程学院,杭州310018

出　　处：《低温工程》2013年第3期47-51,共5页Cryogenics

基　　金：国家重点基础研究发展计划(973计划)(2011CB706501)

摘　　要：采用分子动力学模拟方法,考虑氧分子中原子间键的谐振势作用,研究了双原子氧的平衡态气液相变特性以及不均匀相界面区的表面张力等性质。根据双原子氧气液相饱和密度的实验数据,确定Lennard-Jones势能模型中氧原子的参数,模拟得到了不同温度下气液相的密度和饱和压强,与实验数据符合良好,验证了确定的氧原子参数的正确性。通过模拟得到了界面压力张量的法向和切向分量的分布曲线以及界面表面张力随温度的变化曲线,在气液界面区,压力张量的法向与切向分量存在较大的势阱和势垒,界面的表面张力随温度线性降低,当达到临界温度时,表面张力减小到0。The gas-liquid phase change characteristics of diatomic oxygen and the surface tension properties in heterogeneous interface zone were studied using the molecular dynamics simulation.The resonance potential between two oxygen atoms was taken into consideration.The potential energy parameters of oxygen atom in Lennard-Jones potential model were firstly determined according to the experimental data of gas and liquid saturation density of oxygen molecule.The saturation densities of gas and liquid phase,and the saturation pressures of the system at different temperatures were then obtained.The numerical results agree very well with those of experimental data,which proves the correctness of present derived potential parameters.The distributions of normal and tangential stress tensors under different temperatures across the gas-liquid interface were obtained and the variation of surface tension with temperature was achieved.There exist large potential well and potential barrier in normal and tangential stress tensor across the interface.The surface tension decreases linearly with the increase of temperature.When the temperature reaches the critical temperature,surface tension decreases to zero.

关 键 词：分子动力学模拟 双原子分子 气液界面 表面张力 

分 类 号：TB61[一般工业技术—制冷工程] TB63