| Abstract [eng] |
Precise control of microscale fluid flow plays a significant role in biotechnology applications. Microfluidics structures, such as microcavities, have been widely applied in various biomedical, biochemical, and high-throughput screening applications. However, the particles trapping mechanism into microchannels are not fully understood yet and demands further research. Particles separation and trapping can be performed using various techniques. In the present work, investigations are focused on inertial microfluidics. Hydrodynamic forces, such as wall-induced and shear-induced lift forces, are employed to control particle behaviour in the microcavities. In this work, the capabilities to trap microparticles in rectangular microcavities with rounded bottom corners are investigated experimentally. Also, microparticles' behaviour in the microchannels and microcavities are analyzed depending on cavity geometry and Re number. A Series of experimental investigations are performed at different Re numbers to determine threshold values of particles that are trapped in a micro vortex and pass microcavity without trapping. Also, the behaviour of microparticles is related to the flow structure in the cavities. Therefore, flow fields obtained by micro-PIV equipment are used to ascertain flow structure influence on particle behaviour. Fundamental knowledge and its generalization of particle trapping and overall behaviour regularities depending on controlling parameters, such as geometry and flow regime, will serve as a roadmap to aid the development of the optimal design of micro-and nanofluidic devices. This study extends the research area of flow dynamics in microcavities where shear layer growth is caused by the interaction of separated and recirculated flows. |
