Analysis of Rotor Dynamics Characteristics of Roots Hydrogen Circulation Pump

As an important part of the Roots hydrogen circulation pump, the rotor system has a significant impact on the dynamic characteristics of the Roots hydrogen circulation pump. In this paper, the finite element model of the rotor system of the Roots hydrogen circulation pump in the fuel cell hydrogen supply system was built, and the dynamic characteristics of the coupled dual-rotor system were studied. Through the modal analysis of the rotor system, the first six-order natural modes and natural frequencies of the uncoupled single-rotor system and the coupled dual-rotor system were obtained. The harmonic response characteristics of the rotor system were analyzed on the basis of the modal analysis, and the harmonic response characteristic curves of the gear and the edge of the impeller were obtained. The results show that the vibration deformation of the shaft end and the rotor impeller is relatively large, and the vibration response amplitude of the rotor system is the largest when the excitation frequency is close to the first-order natural frequencies. The coupled dual-rotor system exhibits more complex vibration modes compared to the uncoupled single-rotor system, and the response of the active rotor system to the imbalance is more significant. It is recommended to give priority to the machining and installation accuracy of the active rotor system, and avoid the excitation frequency near 980Hz to help improve the stability of the Roots hydrogen circulation pump. The research will provide a basis for the optimal design and vibration reduction research of the Roots hydrogen circulation pump, thereby improving the reliability of the rotors during operation.