Analysis of weakly compressible fluid flow in nano /micro-size circular tubes considering solid wall force
Analysis of weakly compressible fluid flow in nano /micro-size circular tubes considering solid wall force
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发表时间：
2014
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通讯作者：
Zhang Xue-lin
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作者：
Zhang Xue-lin
针对纳米/微米管内流体流动偏离哈根-泊肃叶定律但其机理尚不清楚的问题，考虑流体的弱压缩性和管壁作用，重点研究纳米/微米圆管内流体的流动。将管壁作用作为壁力引入动量方程中,推导了流体动力涡流方程,得到了压力和速度的一阶摄动解。发现存在零级径向压力。由于壁面-流体相互作用的影响，一阶径向压力增大，一阶速度减小。由于流体的可压缩性和管壁力，无量纲体积流量偏离不可压缩流体。无量纲体积流量与泊肃叶流的偏差随着管壁作用的可压缩系数和液体离子浓度的增大而增大，随着管径的减小而增大。当管径小于一定尺寸时，液体不能流动。本文揭示了纳米/微米尺寸的微尺度效应是由流体的可压缩性和管壁力共同作用的结果。
Aiming at the problem that fluid flow in nano /micro-size tubes deviates from the Hagen-Poiseuille law but the mechanism remains unclear to date,this paper focuses on fluid flowing in a nano /micro-size circular tube considering the weak compressibility of the fluid and the tube wall action. The tube wall action was introduced into the momentum equations as a wall force,the hydrodynamic vorticity-stream equations were derived,and the first-order perturbation solutions of pressure and velocity were obtained. It is found that there exists zero-order radial pressure. Due to the influence of wall-fluid interaction,the first-order radial pressure increases and the first-order velocity decreases. The dimensionless volume flow rate deviates from an uncompressible fluid due to the compressibility of the fluid and the tube wall force. The deviation of the dimensionless volume flow rate from Poiseuille flow increases with the increasing of compressible coefficient and ion concentration in the liquid acted with the tube wall,and increases with the decreasing of the tube diameter. The liquid cannot flow when the tube diameter is less than a certain size. This paper reveals that the mirco-scale effect of nano /micro-size is resulted from the compressibility of the fluid and the tube wall force together.