Numerical Investigation of Solid-Liquid Two Phase Flow in Converging-Diverging Microchannel, Using Eulerian-Eulerian Approach

Solid particles migration in liquid phase through microchannels is considered to be the most important issue in microfluidic systems. Converging-Diverging microchannels are being used in manufacturing the microfluidics tools such as micro-switches, micro-sensors and micro-filters. In this research, 3-D numerical simulation based on Eulerian-Eulerian approach was performed on solid-liquid two-phase flow in a converging-diverging microchannel with 200 μm height. The size of particles used in this research is 20μm with density of 1.05 gr/cm3. The results showed that the most particle accumulations occured in the regions close to the walls before and after the nozzle, but in the converging part of the nozzle, the amount of particles even near the walls decreased due to the increase in flow velocity. Furthermore, increasing the Reynolds number leaded to increase in the amount of particles accumulated at the throat and reached its maximum value. Compared with similar studies, this study investigates the effect of converging-diverging geometry of the channel on particle sedimentation. The results show that using converging-diverging channel provides the possibility to prevent the destructive phenomenon of channel blockage.