Shear Stress Analysis in a Ferrofluidic Magnetic Micropump

Abstract

The article presents analytical and numerical computational fluid dynamics (CFD) simulations of the flow performance in a newly introduced ferrofluidic magnetic micropump, with the purpose of estimating the stress distribution in its flow field. Analytical expressions were developed for the shear stress generated at the upper and lower walls of the pump's channel in terms of dimensionless parameters by solving the Navier-Stokes equation in cylindrical coordinates. CFD simulations have demonstrated that the shear stress is small in the majority of the pump's channel and assume significant values only in narrow strips near the walls. The analytical predictions were compared with those obtained from CFD and were found to be in very good agreement for . For larger aspect ratios, the CFD predictions were found to be lower than the analytical predications. The analytical estimates provide an upper limit on the shear stress and may be used reliably for a conservative estimate of the stress.