Energy Storage Science and Technology ›› 2021, Vol. 10 ›› Issue (5): 1536-1543.doi: 10.19799/j.cnki.2095-4239.2021.0339

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Vibration of double-cantilever shafting structure passing through critical speed

Dongxu HU1,2(), Xinran WANG1,2, Wen LI1,2, Xingjian DAI1,2, Xing WANG1,2, Hucan HOU1, Haisheng CHEN1,2,3, Zhitao ZUO4()   

  1. 1.Institute of Engineering Thermophysics, Chinese Academy of Science, Beijing 100190, China
    2.University of Chinese Academy of Sciences, Beijing 100049, China
    3.Nanjing Institute of Future Energy System, Nanjing 211135, Jiangsu, China
    4.National Energy Large Scale Physical Energy Storage Technologies R&D Center of Bijie High-tech Industrial Development Zone, Bijie 551712, Guizhou, China
  • Received:2021-07-13 Revised:2021-07-19 Online:2021-09-05 Published:2021-09-08

Abstract:

Expander and compressor are the important components of compressed-air energy storage (CAES) systems. To meet the requirements of off-design and low power consumption, the double cantilever shafting structure is used often. However, the vibration of the double cantilever shafting structure is prominent, whereas there are insufficient studies on it, and the related technology is mostly controlled by foreign giants. Based on this, herein, an experimental study of the vibration of the double cantilever shafting structure was conducted. By several speed-up-and-down experiments, the vibration amplitude curve, vibration spectrum, Bode diagram, and vibration energy distribution spectrum of high-speed shafts are analyzed and the critical speed of the rotor is determined. The influence of speed-up continuity and time on the amplitude through the critical speed is then explored. The results show a critical speed of 14200 r/min for the high-speed shaft of the double-cantilever test piece. The resonance region below the critical speed is about 15%, and that beyond the critical speed is about 9%. When the speed is close to the critical value, the increasing range of other frequencies is 2 μm, which is less than 5% of the fundamental frequency increase. Through the critical speed, the speed-increasing continuity has an impact on the amplitude. This study presents two types of speed-increasing schemes. Although the acceleration of scheme 2 is faster when passing through the critical speed, the vibration energy accumulates as it is close to the critical speed, making the vibration peak of scheme 2 larger than that of scheme 1. Through the critical speed, the vibration peak increases approximately linearly with an increase in the speed-increasing time. When the speed-increasing time is increased from 20 to 60 s, the amplitude increases by about 20%.

Key words: double cantilever, critical speed, vibration, experiment

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