微通道中颗粒惯性聚集的力学特性

为揭示微通道内悬浮颗粒惯性聚集现象的机理,基于相对运动原理,利用数值方法研究了单个球形颗粒在方形微通道中的运动状况,并对颗粒的受力特性进行分析.研究发现:较小粒径的颗粒在较高通道雷诺数下可产生惯性聚集现象,但其受到的惯性升力在通道截面横向位置分布具有很大的波动性;惯性聚集位置随通道雷诺数的增大向通道壁面移动,随颗粒粒径的增大向通道轴心移动;颗粒旋转产生的旋转诱导惯性升力使惯性聚集位置向通道壁面移动.惯性升力分为旋转诱导升力和由剪切诱导升力及壁面诱导升力合成的非旋转诱导升力,而后者是惯性升力的决定性部分.

Mechanical Characteristics of the Inertial Focus of Particles in Microchannel

In order to reveal the mechanisms of the inertial focus of buoyant particles in microchannel,the relative motion principle and numerical method were utilized to study the mechanical behaviors of a single spherical particle in rectangular microchannel with squared section,and some discussions were presented.The results show that in terms of particles with fairly small size,as the Reynolds number of flow increases to a certain extent,the inertial focus will appear, while the distribution of inertial lift on particles with fairly small size is instable on the lateral section of flow channel.Both the particle's rotation and the increased Reynolds number can lead the focus position to move towards the channel wall,while it will move away from the channel wall as the particle's size increases successively.The inertial lift consists of two components,the rotation induced lift and the non-rotation induced lift.The latter is the decisive component of inertial lift,which is composed by shear induced lift and wall induced lift.