Multibody dynamic characteristics of a co-rotating scroll hydrogen recirculation pump

Co-rotating scroll hydrogen recirculation pump (CSHRP) for hydrogen fuel cell-powered vehicles is characterized by compactness, high efficiency, and low noise, which have brought it into the spotlight. However, the dynamics of the CSHRP in multi-clearance coupling conditions are still poorly understood. To fill the gap, this study utilized multibody dynamics simulation technology to investigate the behavior of the critical components within the CSHRP. The study focuses on radial clearance (RC) variations under coupled bearing clearances, as internal leakage critically affects CSHRP performance. The contact forces of the sub-crankshaft (SC) are also investigated. Results show that, under operating conditions, the actual RC is 20–60% lower than the design value, and the residual RC decreases as the bearing clearances increase. The RC is particularly sensitive to the bearing clearances of both the main shaft and the slave scroll shaft. Moreover, the flexibility of the main shaft further reduces the residual RC by approximately 1 μm. With revolute joint clearance, the radial impact load on the SC can be as high as 160 kN, more than 200 times higher than the load with no clearance. The expected service life of SC bearings is relatively short, ranging from 61 to 228 h. This study offers new insights into the design of high-reliability hydrogen recirculation pumps.