Transient performance of flow over a rotating object placed eccentrically inside a microchannel-numerical study

Industrial applications today are demanding the implementation of microelectromechanical systems (MEMS) into their products. These are mechanical devices that are able to perform work, and yet have characteristic lengths less than I mm. As a result, the Reynolds number is typically low, which indicates the dominance of viscous forces. When a cylinder is placed eccentrically inside a microchannel, where the rotor axis is perpendicular to the channel axis, a net force is transferred to the fluid as a result of the unequal shear stresses on the upper and lower surfaces of the rotor. Consequently, this causes the surrounding fluid in the channel to displace towards the microchannel outlet. The present numerical investigation is a comparative study of transient flow behavior in a microchannel with rotating cylinders with different cross-sectional geometries. The effects of channel height, eccentricity, Reynolds number, and pump load were studied, as well as the development of their respective streamlines and pressure contours. The steady state results were compared with existing numerical and experimental results, and the comparisons showed very good agreement.