Research On Characteristics Of Hydraulic Vibration Source And Precise Application Of Hydropower House Based On CFD

The hydraulic vibration source is the most important factor causing the vibration of powerhouse structure, and it is also the most difficult factor to describe and simulate. Because of the complexity of water in the internal flow passage of hydraulic turbine, the integrity of the flow channel can not be reflected by the flow characteristics of single component. This paper analyses the current research of hydraulic vibration source characteristics and applied methods.based on the characteristics of the hydraulic vibration source calculated by CFD, the law of hydraulic vibration source of hydraulic turbine runner, especially on the wall, is studied, and a accurately calculating method is proposed.The unsteady turbulent flow numerical model of the whole passage is builded, and the calculation is based on the SST two-equation model to realize the full unsteady turbulent flow.And the distribution characteristics of pressure fluctuation in the spiral case and the wall of the draft tube are analyzed. The amplitude, frequency and regularity of hydraulic source are summarized.On the basis of CFD calculation, harmonic response analysis is used to study the reasonable description and accurate simulation. Based on the characteristics of the amplitude and frequency distribution of the vibration source, the area of the spiral case wall is divided into five simplified schemes. The plant dynamic response numerical calculation results show that the vibration responses ar greater compared with the traditional flow of single frequency and amplitude if the pressure amplitude and frequency data of typical representative points in each region are applied to the surface of the region as a harmonic surface pressure, which is close to the real effect of the hydraulic source. It can be seen that the traditional method will lead to the danger of the design of the hydropower house. Due to the difference between the grid size of the plant structure and the fluid model, the preparation of CFD calculation of pressure rippleresults into the plant structure program through the ANSYS second development. The location of points on spiral case and draft tube are one-to-one correspondence. Use the SFFUN command to achieve real-time and accurate simulation of pressure fluctuation of each node on channel wall according to CFD simulation results, and the plant response is compared with the tradition method. The results show that the simulation method based on CFD is applied to the accurate simulation of fluctuating pressure, which takes into account the amplitude of the vibration source and the frequency difference.