流道特性对流体压力影响的分子动力学研究

Abstract

应用分子动力学方法研究纳米流道不同固–液间相互作用势能指数对液体流动特性的影响。研究结果显示，纳米尺度下流道出口高度及固液间相互作用势能不同会引起流体压力的改变，并出现射流现象。出口端距离较小时，流道内液体流动规律不再服从NS方程——按照分子动力学模拟与按NS或Renolds方程求解得到的压力分布结果存在较大的差异，此时射流现象比较明显，射流速度随着固液间势能指数的增强呈线性增大趋势。随着出口端高度的增加，纳米尺度效应减弱，压力分布逐渐趋近宏观流动下的压力分布曲线，固液间势能指数对于射流速度的大小不再产生明显的影响。 Molecular dynamics method is applied to study the influence of potential interaction strength be-tween the liquid and the solid on the properties of fluid film in nanochannels. The results indicate: the pressure distribution of fluid film is changed in Nanochannels with the change of the height of channel in the outlet end and the liquid-solid potential interaction strength. At the same time, the jet phenomenon can occur in the outlet end. The difference of the pressure distribution between the results obtained by molecular dynamics simulation and that by NS or Renolds equation is much bigger. At this point, the jet phenomenon is more obvious. The jet velocity increases linearly as the liquid-solid potential rises. With the increasing height of the outlet, the nanoscale effect becomes weaker and weaker. The pressure profile gradually approaches to that of the macro-flow. The liquid-solid potential has no significant effect on the jet velocity.