Three-dimensional CFD Modelling of a Roots Blower for Hydrogen Recirculation in Fuel Cell System

Abstract

Fuel cell system has gained extensive attention due to increasing tendency of environmental protection, and Roots blower has great potential as the recirculation pump in its hydrogen recirculation system while there are rare of research about this ancillary component. In this paper, a three-dimensional, transient model of a three-lobe Root pump was established and solved and the internal flow characteristic was investigated. The results show that pressure ratio can influence the mass flow rate and torque significantly and high pressure ratio will lead to mass flow reflux. The most dramatic variation of pressure occurs in the moment that the displacement chamber connects with the exhaust region. The vortex will arise from both the inlet and outlet pocket. Different methods are needed to reduce the vortexes since their position are quite different in the inlet and outlet pocket.