Optimal Design and Performance Simulation of a Novel Semi-Active Vibration Absorber for Pipeline System of NPP

The vibration of pipeline system induced by pump is one of the most important factors affecting the safety and stability of nuclear power plant (NPP) operation, and is also the most prominent vibration and noise transmission channel in the plant area. Analysis results show that various support structures such as pipe clamps, hangers and brackets are the main transmission routes of pipeline vibration. However, it is usually difficult to obtain a satisfactory absorption effect by using traditional passive vibration isolation device, especially for a variety of low-frequency vibration. Besides, the effective isolation frequency is fixed which cannot adapt to the variation of the operation condition excitation source. Therefore, it is of great practical significance to propose a method and scheme which can effectively restrain the low-frequency vibration of pipeline system of NPP. In order to meet the above requirements, an electromagnetic semi-active vibration absorber is designed in this paper. Its electromagnetic stiffness can be adjusted by changing the excitation current, so as to achieve the purpose of changing the natural frequency online and improving the vibration attenuation effect. In order to verify the rationality of its electromagnetic structure, the magnetic field distribution of vibration absorber is simulated and analyzed. Results show that it is close to magnetic saturation inside without leakage. On this basis, a platform of simulated condensate water pipeline system for vibration experiment is set up, on which the frequency response together with time & frequency-domain vibration characteristics of typical support points are tested, and the stiffness, damping and other parameters of the vibration absorber are optimized according to the test results. Finally, the vibration of pipeline system is simulated and compared. The results show that under the condition of the optimal combination of parameters, the vibration spectrum of the pipeline is obviously reduced after the vibration absorber is used, which indicates a significant vibration control effect.