CAJ | 학술논문

采用分子动力学方法模拟研究了不同压力下小分子气体在液压油中的扩散.模拟过程中均选用PCFF力场,首先对模拟体系进行NPT下500ps时间的动力学优化,随之进行NPT下500ps时间动力学模拟,得到其运动轨迹,并由爱因斯坦方程得出气体小分子在液压油中的扩散系数.该文还应用自由体积理论探究了小分子气体在液压油中的扩散机理,发现气体在液压油中以空穴形式存在的自由体积间进行扩散,即气体的扩散是通过先在一个空穴内不停振动,然后跳跃到下一个空穴来完成的.结果表明,随着压力的增大,小分子气体在液压油中的扩散系数是减小的.
채용분자동역학방법모의연구료불동압력하소분자기체재액압유중적확산.모의과정중균선용PCFF력장,수선대모의체계진행NPT하500ps시간적동역학우화,수지진행NPT하500ps시간동역학모의,득도기운동궤적,병유애인사탄방정득출기체소분자재액압유중적확산계수.해문환응용자유체적이론탐구료소분자기체재액압유중적확산궤리,발현기체재액압유중이공혈형식존재적자유체적간진행확산,즉기체적확산시통과선재일개공혈내불정진동,연후도약도하일개공혈래완성적.결과표명,수착압력적증대,소분자기체재액압유중적확산계수시감소적.
The paper studies on the effects of pressure on gas diffusion in hydraulic oil by molecular dynamics simulation. The whole simula-tions were processed under PCFF force field. Refined the simulation system by NPT ensemble in 500ps firstly, the diffusion coefficients were determined by NPT ensemble simulation in 500ps.thencalculatedit from the Einstein relation. The small gas diffusion mechanism in hy-draulic oil is also discussed according to free volume theory. Small gas molecules firstly oscillate inside one cavity of hydraulic oil and then jump from this cavity to another one to achieve the diffusion process. The results showed that the diffusion coefficient decreases with the ris-ing pressure.