Exploring fluid flow in microchannels with branching and variable constrictions

Abstract

We employ a three-dimensional numerical model to analyze the dynamics of single-phase flow in a parallel branched microchannel with varying geometric dimensions of constrictions. The primary objective is to delve into the intricacies of flow within microdevices featuring a branched network and constrictions. The findings illustrate nonlinear variations in velocity, pressure, acceleration, and shear stress along the streamwise direction, underscoring their significant dependence on the converging/diverging angles of the constrictions. To gain deeper insights into the effects of geometric parameters resulting from converging/diverging constrictions in microchannels, a geometric Reynolds number is introduced as the governing parameter for flow transition, further highlighting the novel approach. Our results demonstrate a notable improvement in the magnitude of inertial forces, a feature uncommon in simple microchannels. From the results, it is asserted that microdevices with higher converging–diverging angles combined with lower width ratios are a preferable choice compared to those with lower converging–diverging angles and higher width ratios. Such configurations exhibit lower pumping power, contributing to enhanced energy efficiency. These findings provide fundamental insights that can guide the design of necessary modifications aimed at improving the performance of micropumps or microvalves.