Experimental investigation of slip velocity and settling distribution of micro-particles in converging–diverging microchannel

An experimental test bed based on single particle tracking techniques is employed in order to investigate the velocity domain, slip velocity, and settling distribution of micro-particles in low-Reynolds number poiseuille flow in converging–diverging microchannel. Three-dimensional velocity domain of particles are studied in the presence of walls and compared with the particle-free fluid. The results show that the velocity of particles moving near the side walls of microchannel decreases about 30 % compared to those moving at the centerline. Furthermore, the effects of converging–diverging geometry on sedimentation of micro-particles are considered. The results show an average decrease of about 40 % in sedimentation of particles among the total particles in converging–diverging channels which is one of the main advantages of these channels in comparison with the straight types.