导航

Acta Aeronautica et Astronautica Sinica ›› 2024, Vol. 45 ›› Issue (2): 228652-228652.doi: 10.7527/S1000-6893.2024.28652

• Solid Mechanics and Vehicle Conceptual Design • Previous Articles    

Dynamic behavior of seal-rotor system in a supercritical carbon dioxide turbine during acceleration transition

Heyong SI, Yaoli WANG, Lihua CAO, Dongchao CHEN()   

  1. School of Energy and Power Engineering,Northeast Electric Power University,Jilin  132012,China
  • Received:2023-03-06 Revised:2023-04-14 Accepted:2023-05-04 Online:2023-05-09 Published:2023-05-09
  • Contact: Dongchao CHEN E-mail:cdc@neepu.edu.cn
  • Supported by:
    National Natural Science Foundation of China(52206004)

Abstract:

There is a strong coupling relationship between the seal aerodynamic characteristics and rotor motion of supercritical carbon dioxide turbine. The dynamic characteristics of the seal-rotor system undergo uncertain changes in rotor acceleration transition. The user-defined function of the seal-rotor nonlinear whirling model was established based on dynamic equations, which enables the synchronous coupling analysis of seal flow field simulation and rotor dynamics. The seal aerodynamic characteristics and the rotor motion characteristics during the rotor acceleration transition were obtained, and the evolution law of the dynamic characteristics of the seal-rotor system was revealed. The results show that, with the increasing of rotation speed, the rotor whirling center moves laterally in the precession direction, and the whirling radius increases gradually. The rotor whirling center sinks first and then rises. The seal dynamic coefficients fluctuate significantly in the process of rotor acceleration transition. The absolute value of stiffness is large in the high-frequency range, and the absolute value of damping is small. The effective damping has a large fluctuation, and the seal stability is reduced. In the low-speed operation range, the direct stiffness and cross stiffness have significant high-frequency amplitude. In high-speed range, the direct damping has prominent low-frequency amplitude. The increasing of rotation speed makes the fluctuation of effective damping gradually migrate to high frequency. The effective damping has higher amplitude and concentrated distribution around 200 Hz.

Key words: supercritical carbon dioxide, seal-rotor system, nonlinear whirl, acceleration transition, dynamic behavior

CLC Number: