摘要
建立一个简单模型以描述球状颗粒弹性变形特征,并根据'运动相对性原理',提出一种描述弹性颗粒准定常运动的数值计算方法,据此研究在方形截面微通道层流场中,弹性球状颗粒所受惯性升力的空间分布特征,揭示了颗粒的弹性变形对惯性升力的影响特点。研究结果表明:弹性颗粒在低Re数通道内运动时,仍存在稳定的横向聚集位置。与对应刚性颗粒相比,弹性颗粒的聚集位置更靠近通道中心,且随颗粒弹性的增加,其聚集位置会向通道中心偏移;弹性颗粒所受惯性升力的空间分布特征与刚性颗粒相似,但颗粒弹性变形会额外产生一个附加升力。这个附加升力的方向始终指向通道中心且随弹性颗粒变形幅度的增加而增大;弹性颗粒所受的惯性升力由'切应力分量'与'压力分量'构成,然而后者是诱发弹性颗粒产生惯性聚集运动的力学成因。
A simple model is presented to describe the elastic deformation of a spherical particle, by which a numerical approach is proposed to describe the quasi-stationary motion of an elastic particle translating in the laminar flow of a squared micro-channel based on the ＇Motion Relativity＇. The behavior of the inertial lift exerted on an elastic particle is numerically investigated and the emphasis of this study is to reveal the influence on the inertial lift by the deformation of the elastic particle. Results indicate that there is always a transverse focused position for an elastic particle translating in a laminar micro-channel flow with low Reynolds number. The focused position of an elastic particle may shift closer to the centerline of the channel than that of a rigid particle, with the increased deformation of the elastic particle. The behavior of the inertial lift exerted on an elastic particle is similar with that exerted on a rigid particle but there is an extra lift exerted on an elastic particle, resulted by the deformation. This extra lift is always towards to the centedine of the channel and its magnitude may increase with the increased deformation of the elastic particle. The inertial lift can be divided into a ＂viscous component＂ and a ＂pressure component＂ while the latter is a critical formation mechanism for the inertial focus of elastic particles.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2015年第14期160-166,共7页
Journal of Mechanical Engineering
基金
国家教育部博士点基金资助项目(20113120120003)
关键词
颗粒惯性聚集
弹性颗粒
惯性升力
附加升力
惯性微流
inertial focus of particles
elastic particle
inertial lift
extra lift
inertial microfluidics
