Numerical modeling of non-Newtonian flow in viscous micropump

Non-Newtonian fluid can be encountered in many applications of Microdevices. In this study, two-dimensional non-Newtonian simulations of viscous micropump were performed. The viscous micropump consists of a rotating cylinder located eccentrically inside a microchannel. When the cylinder rotates, a net force is transferred to the fluid due to the unequal shear stresses on the upper and lower surfaces of the cylinder, thus causing the fluid to displace. Navier Stokes equations and modified Bingham model have been used to describe the fluid flow. Parameters as viscosity and stress used in the model are based on experimental data. It was found that Reynolds number is a predominant parameter on the variation of bulk velocity as a function of eccentricity. The stress and bulk velocity decrease with increasing the eccentricity at low Reynolds number. The changes in non-Newtonian fluid structure are related to Reynolds number, eccentricity and channel height. The pumping performance of non-Newtonian fluid is increasing with global pressure gradient and decreasing with the channel height.