基于分子动力学模拟的流体剪切力学特性分析

发布时间：2018-03-11 12:06

  本文选题：分子动力学　切入点：剪切力学　出处：《北京理工大学学报》2017年09期 　论文类型：期刊论文

【摘要】：考虑固体壁面对流体分子作用力的影响,建立了两平行壁面-流体系统的分子动力学模型,模拟了壁面切向运动对流体的剪切过程,分析了壁面速度对不同离壁距离流体层微观剪切力学特性的影响,研究了剪应变率、工作压力和温度对流体宏观剪切力学特性的作用规律.研究表明:受到分子无规则热运动的影响,不同离壁距离流体层的剪切应力呈现出波动变化状态,但随着流体剪切运动的增强,剪切应力的波动幅值逐渐减小;当壁面切向运动较大时,近壁层流体在运动速度上与壁面之间易出现较大的滑动,壁面-流体出现边界滑移;工作压力及温度影响着分子间距离,压力升高与温度降低都将减小分子间的距离,从而引起流体黏度与剪切应力的增大.
[Abstract]:Considering the influence of solid wall on the molecular force of fluid, a molecular dynamics model of two parallel wall-fluid systems is established, and the shear process of the wall tangential motion to the fluid is simulated. The influence of wall velocity on the micro shear mechanical properties of fluid layers with different distance from the wall is analyzed, and the shear strain rate is studied. The effect of working pressure and temperature on the macroscopic shear mechanical properties of the fluid. The results show that the shear stress of the fluid layer at different distance from the wall fluctuates under the influence of the irregular thermal movement of the molecule. However, with the increase of shear motion, the fluctuation amplitude of shear stress decreases gradually, and when the wall tangential motion is larger, the near wall layer fluid tends to slip between the wall and the wall at the velocity of movement, and the boundary slip occurs between the wall and the fluid. The pressure and temperature affect the distance between molecules. The increase of pressure and the decrease of temperature will decrease the distance between molecules, which will lead to the increase of fluid viscosity and shear stress.
【作者单位】： 北京理工大学车辆传动重点实验室;
【基金】：国家自然科学基金资助项目(51305033) 北京理工大学车辆传动重点实验室基金资助项目(9140C340506)
【分类号】：O35
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本文编号：1598091