Flow characteristics of gerotor vacuum pumps with multistage designs

Abstract

This paper investigates the effect of multistage designs on flow characteristics of a gerotor type vacuum pump connected in serial and parallel. The three-dimensional computational fluid dynamics (CFD) models are established based on dynamic mesh method to simulate the fluid flow. The effects of serial versus parallel designs on fluid flow rate, pressure ripple, outlet flow velocity and fluid moment are explored and described in details for 2 to 4-stage designs. The analysis results show that both serial and parallel connection designs have relatively better flow characteristics for 3 and 4-stage designs as compared to 2-stage design however the greater stage designs encounter leakage issues and power losses. For the same number of stages, the flow rate, pressure ripple and outlet flow velocity are significantly greater in the parallel connection with multistage design as compared to serial connection. Taking into consideration all the flow aspects, a 3-stage design connected in parallel can be an economical and efficient design.