Model experiment, numerical simulation and theoretical analysis on the characteristics of a viscous micropump using a cylindrical rotor in a rectangular duct

Abstract

The present paper describes the characteristics of a viscous micropump with a cylindrical rotor in a rectangular duct. In the model experiment, the low Reynolds number flow is realized by using glycerin as a working fluid for a centimeter-scale (non-micrometer-scale) pump model. In the numerical simulation, the commercial code, STAR-CD, is used. Qualitative and quantitative agreements between the experimental and numerical results are obtained with respect to the flow fields and the pump characteristics, i.e. pressure performance and pump efficiency. The experimental and numerical results show that there exist three recirculations near the rotor, rotating in the opposite direction of the rotor. They also show that pressure performance represents a straight line with a negative slope. In the theoretical analysis, the Buckingham's pi theorem is applied with the low Reynolds number approximation. As a result, two new dimensionless parameters are obtained for flow rate and pressure rise. By using the two new dimensionless parameters, the unified treatment of pressure performance is possible, independent of the Reynolds number. The low Reynolds number approximation is valid when the Reynolds number is smaller than 100.