| A large proportion of high-lift water transfer pumping stations were constructed during the 1970 s and 1980 s in China. Account for the long-term running, most of the pumping stations had potential security problems to varying degrees, such as biggish pipeline vibration amplitude, high running noise and so on. And the vibration of pressure pipeline would directly affect the security and efficiency of the whole water transfer pipeline system. The research on vibration characteristics of pressure piping at high-lift pumping station was carried out to further analyze the reasons for the pipeline vibration and study the vibration mechanism, which is of great practical significance to ensure the security running and improve the operating efficiency of pressure pipeline at large-scale pumping station.The 1# pipeline of seven pumping station on the main line in Jingtaichuan electrical lifting irrigation second-stage project was selected as the study object in this article. It used the DASP(Data Acquisition & Signal Processing) to conduct the field test and the numerical fluid-solid coupling model of the study object was established with ANSYS, which were to identify the excitation sources of pressure pipelines and units at pumping station as well as confirm the positions easily occurring deformation during the operation, and then obtain the main vibration source and its main frequency of the pressure pipeline in different working conditions to analyze the vibration characteristics of pressure pipeline.Concrete research contents include: ①Conduct the field test and collect data with DASP, preparing for the analysis of excitation sources; ② Explore the causes of pipeline vibration with time-domain analysis method and find out the positions easily occurring deformation under different working conditions; ③ Detect the vibration sources and corresponding frequencies of pressure pipeline with the spectrum analysis method in the processes of start-up and steady running, and then confirm the main sources causing the pipeline vibration by power spectrum method under different working conditions; ④ Establish the finite element simulation model with ANSYS based on fluid-structure interaction and adopt the additional water mass method to simulate the impact of water on the vibration of pipe shell, analyzing the vibration of pressure pipeline of different working conditions; ⑤ Study the vibration characteristics of pressure pipeline through comparing the results of field test and finite element simulation.The main research conclusions are as follows:(1) The DASP analysis results show that, the vibration sources of pressure pipeline at high-lift pumping station are hydraulic excitation, mechanical vibration and electromagnetic vibration caused by centrifugal pump and other equipment as well as the pipeline self-vibration. The main vibration source in start-up process is hydraulic excitation, the main vibration source in steady running process is mechanical vibration, and during the shut-down process the main vibration source firstly is electromagnetic vibration and later the mechanical vibration.(2) The results of finite element simulation with ANSYS say that the vibration is obvious at the bend sections and pipe joints between large and small caliber, which agree with the field test results.The conclusions in this research could not only provide valuable references for pipeline structure design of similar to-be-built projects, but offer lessons for construction, maintenance and safety operation of pressure pipelines in high-lift water transfer pumping stations. |
