Numerical study of a positive displacement blower

Abstract

The evolutionary characteristics of flow for the positive displacement blower were identified and visually analysed by performing numerical simulation of unsteady compressible flow in an involute-type three-lobe positive discharge blower using computational fluid dynamics. The two exhaust rate curves obtained by the semi-empirical method and the simulation were compared, and the differences were analysed by showing pressure contours and velocity vectors at different moments in one working period. The simulation results showed the exhaust rate having two V-type fluctuations, whereas the semi-empirical method shows the exhaust rate having only one V-type fluctuation. These differences are due to pressure fluctuations and the existence of a vortex in the mixing zone.