Research on numerical method of flow-induced vibration on spiral casing structure of large-scale hydropower station

Abstract

The water flow in turbine flow passage is one of the prime reasons that lead to the vibration of the spiral casing structure of large-scale hydropower station, and the fluid-structure interaction of the spiral casing structure is very complex. In this study, a numerical method it presented, which could simulate the vibration of spiral casing structure that caused by the water flow in turbine flow passage. The numerical simulation of 3-D unsteady turbulent flow through the flow passage of turbine model is accomplished by solving the N-S equations, and the flow fields of flow passage and dynamic water pressure on boundary are obtained. At the same time, the three-dimension finite element dynamic model of solid structure is established, which contain steel liner and concrete surrounding the spiral case. And then, the three-dimensional instantaneous analysis of solid are proceeded as well as the dynamic water pressure transfer real-time by user interface program on interface at which the fluid interacts with solid. The one-way coupling analysis between fluid and solid structure is realized, through which the stress field and displacement field of solid induced by water flow are obtained. At last, a case study of a spiral casing structure which located in a hydropower station in Yunnan Province is presented.