Claw-type pump is one of the most promising candidates in the circulating system of the hydrogen fuel cell because of its compact structure and high reliability. In this paper, claw-type hydrogen circulating pump with a rated flowrate of 0.4 Nm 3 Ámin À1 was designed and fabricated. An internal flow model of the claw pump was established to investigate the thermodynamic performances with air. Then, a test rig was carried out to validate the feasibility of the numerical model with air. Finally, the numerical model was used to