浮油密度受温度影响的分子动力学模拟

Molecular Dynamics Simulation of Temperature on the Density of Suspended Oil

浮油是液浮陀螺仪的重要组成部分,陀螺仪工作环境温度分布不均引起浮油密度局部变化,导致产生干扰力矩。有限元方法能够实现液浮陀螺仪温度场的仿真以及干扰力矩的分析,但是缺乏对浮油物化性质及变化的研究。通过分子动力学模拟的方法,建立并优化了氟醚油的分子链以及密度计算模型,得到了分子量和温度对密度的影响。结果表明,氟醚油密度随分子量增大而增大,且模拟数值与实测密度相符。温度升高,氟醚油密度下降,密度与温度之间呈线性相关,且分子量越低密度下降越快。拟合校正后所得到的温密方程实现了浮油性质的定量分析,为有限元仿真和液浮陀螺仪的设计提供了基础参数。

Suspended oil is an important part of liquid floated gyroscope.The uneven temperature distribution of the working environment causes the local changes of the suspended oil density,resulting in the generation of disturbance torque.The finite element method can simulate the temperature field and analyze the disturbance torque of the liquid floated gyroscope,but it’s lack of research on the physicochemical properties and changes of the suspended oil.The molecular chains and density calculation models of perfluoropolyethers are established and optimized by molecular dynamics simulation,and the effects of molecular weight and temperature on density are calculated.The results show that the density of perfluoropolyethers increases with the increase of molecular weight,and the simulated values are consistent with the measured values.The density of perfluoropolyethers decreases with the increase of temperature.There is a linear correlation between density and temperature,the lower the molecular weight,the faster the density decreases.After fitting and correcting the temperature-density equations,the quantitative analysis of perfluoropolyethers properties is realized,which provides the basic parameters for finite element simulation and the design of liquid floated gyroscope.