Design of a novel high-sealing rotor for a double-claw hydrogen circulation pump used in PEMFC and its sealing characteristic analysis

The claw compressor is one of the most promising hydrogen circulation pumps, featuring high reliability, oil-free operation and compact structure. However, the conventional claw hydrogen circulation pump adopts a point-to-point meshing approach at the pitch circle for its two mutually meshing rotors, resulting in severe hydrogen leakage, which is a bottleneck limiting its development. In order to solve this problem, in this study, the authors proposed a novel gear double-claw rotor, which uses arcs, cycloids and parabolas. This novel rotor contains a type of tortuous meshing structure between the claw rotors to increase the gas sealing. Furthermore, a corresponding geometric model for the gear double-claw rotor was constructed, and its cross-sectional profile equations were derived. During operation, the unsteady flow of the internal gas in the novel gear double-claw hydrogen circulation pump that has complicated geometric boundaries was numerically simulated; the pressure distributions and transient flows of the novel pump were compared with those of the conventional pump. The numerical simulation results were experimentally verified. Results show that the proposed gear double-claw rotor is able to significantly enhance the sealing performance; and the gas leakage velocity of the novel rotor during operation decrease by 35.15%.