Figure 1. Balance of particles in a rectangular cross-section spiral microchannel.

The black cones within channel cross-section are the CFD simulation result of the Dean flow field at a flow rate of 3.5 mL/min in a channel with radius 7.5 mm. The figure also shows the vector plot of the Dean drag force on the particle since the force is proportional to the Dean velocity. The experimental images of 15.5 μm fluorescent beads distribution from the top view and side view are placed at the bottom and to the left side of the simulation profile. By combining the top- and side- view observations, the positions of 15.5 μm beads at typical flow rate are drawn as gray circles in the channel cross-section.