Development and analysis of novel six-lobe helical rotors for hydrogen fuel cell vehicle roots blowers

This paper suggests a novel six-lobe Roots profile to improve the performance of Roots blowers in hydrogen fuel cell vehicles. Mathematical models for rotor profile generation and geometric characteristics are established. A working process simulation model for Roots blowers is developed based on the lumped parameter method and is verified by experimental results. The key profile parameters are discussed and optimized in views of geometric and thermodynamic performance. Case studies are conducted to reveal the detailed performance map difference between several design cases. Results show that a trade-off exists between the rotor cavity volume and adiabatic indicated efficiency for Roots blowers. The proposed profile broadens the design space of rotors in tooth height and achieves a flexible adjustment for the leakage through the blow-hole and contact line. As a consequence, compared to conventional Roots profiles, the proposed rotor profile achieves higher adiabatic indicated efficiency under the same rotor cavity volume.