Inertial focusing and ordering in microfluidic channels with non-rectangular cross-sections

Abstract

Microfluidic systems can provide methods for precise manipulation of microparticle, for example, separation, focusing and ordering of microbeads and cells. Majority of microparticle manipulation techniques use external force field such as dielectrophoresis, acoustic wave, magnetic field, which typically lead to low throughput and complicated devices fabrication and operation. Inertial microfluidics can provide high-throughput micro-particle manipulation without sheath flow or external field. However inertial microfluidic phenomena are studied only with rectangular cross-section channels. We studied inertial focusing and ordering in non-rectangular cross-section channels for better understanding mechanism of inertial focusing. We measured fo-cusing positions in triangular and semi-circular cross-section channels with varying Reynolds number. We observed broken symmetry, from rectangular cross-section, leads to two or three focusing positions. These results can be directly utilized to control particle focusing and self-assembly in inertial microfluidic systems.