气柱共振导致的核电站蒸汽管道振动分析与机理研究

针对某核电站机组4#汽动辅助给水泵蒸汽管道在大修后验收试验期间发生的振动超标问题,通过对蒸汽管道振动现象及测试数据分析,推测管道振动机理为主汽门活塞卡滞引发汽锤,汽锤激发管道气柱共振,并使得阀杆产生相应频率即69 Hz的振动.由于阀杆控制系统频响特性,69 Hz与阀杆控制系统耦合,导致管道振动烈度严重超标,达到76 m...

Analysis and mechanism study of nuclear power plant steam pipe vibration caused by gas column resonance

For the problem of excessive vibration of the steam pipe of a nuclear power plant unit 4~# steam-driven auxiliary feedwater pump during the acceptance test after the overhaul，through the analysis of the steam pipe vibration phenomenon and test data，it is inferred that the pipe vibration mechanism is the stuck piston of main valve causing steam hammer，which excites the pipeline gas column resonance，and causes the valve stem to produce a corresponding frequency of 69 Hz vibration.Due to the frequency response characteristics of the valve stem control system，69 Hz is coupled with the valve stem control system，causing the pipeline vibration intensity to exceed the standard，reaching 76 mm/s.Based on the above conjecture，by deriving the plane wave equation，the research was carried out on the calculation method of the natural frequency of the air column，and then the finite element software was used to simulate and calculate the natural frequency of the pipeline air column；the valve control system and the actual model of the actuator was built to analyze the frequency response characteristics of the valve stem control system.The research results show that the steam pipeline has a natural frequency of the gas column consistent with the vibration frequency of 69 Hz of the pipeline，and the valve stem control system can generate positive feedback to 69 Hz，which confirms the correctness of the fault reasoning.