ADVANCES IN THE RESEARCH ON “INERTIAL FOCUS OF PARTICLES” AND ITS APPLICATION IN MICROFLUIDICS

When a flow with randomly dispersed small particles enters a straight pipe at low Reynolds numbers, the particles may migrate to an annulus centered at the axis of the pipe after a migration distance. This migration is called as ‘Inertial Focus of Particles’, which indicates that in the creeping flow there are transverse forces exerted on the immersed particles apart from viscous drags. It is the transverse force that results in the phenomenon, and it is usually regarded as an effect of the inertial force of the flow field on the particles. Recently, the phenomenon is attracting the attention of more and more researchers. Further research on it will not only reveal the interesting dynamic behaviors of both particles and colloids in a micro-channel and organisms in a blood vessel, but also assist us in the exploitation of such separation technology with high efficiency and low energy consumption. This paper summarizes recent advances in this area and presents some suggestions for future research.