Experimental and analytical investigation of micro-particle velocity domain and particle-wall interaction in microchannel

Micro-particles transportation in microfluidics devices is of interest for processing suspensions such as drug delivery, pharmaceutics, and food. Analytical and experimental studies have been conducted to investigate the velocity domain of micro-particles in Low-Reynolds-number Poiseuille flow in a rectangular microchannel. The results are compared with the existing methodologies such as Lattice-Boltzmann simulation and show good agreement. Compared with similar studies, the comparison between the experimental and analytical results provides broader insight into the effects of walls on the hydrodynamic behavior of micro-particles in microchannels. The comparative results show that the velocity domain of the dispersed phase is affected by the particles-fluid hydrodynamic coupling and particles-wall interactions. Also, particles slip velocities can be significant with the increase of particles sizes and proximity to nearby walls. Furthermore, the distance from the walls in which the particle-wall interaction is quite considerable is determined, which is about the order of particles diameter. Also, the number of particles observed near the bottom wall in all particle sizes was approximately 10% to 20% more than the number of particles found near the top wall, indicating the tendency of particles to sedimentation.