Hydrodynamic Focusing of Streams by Confluence of Microchannels

Abstract

Hydrodynamic focusing of the inflow stream from the center channel was studied in a flow system in which the three microchannels converge into a single channel. This system is important as the elementary flow in microreactors in which micromixing is achieved by molecular diffusion without convective mixing. The width of the main stream from the center channel decreases along flow direction by the focusing effect. The dependence of the stream width on the confluence angle, the inlet velocity, and the fluid viscosity was examined both experimentally and by numerical simulation. By visualization of the contacting interface between two inlet fluids, the conditions under which the surface of the contacting interface is deformed after confluence were clarified.