ANALYSIS OF FLOW-INDUCED VIBRATION OF BLADES FOR A FRANCIS HYDRO TURBINE

A fully coupled modeling and numerical simulation of flow-induced vibration of three-dimensional blades for a Francis hydro turbine in unsteady turbulent flow are presented. The methodology used is of the generalized variational principle on a power functional of the fluid-blade system. Three vibrating mechanisms of the blades, turbulent-induced vibration, vortex-induced vibration and fluid elasticity instability, are involved in the establishments with fluid-structure interaction (FSI). A working model turbine was designed and used to implement comparisons with experimental measurements. On the pressure and suction sides of one blade of this turbine, ten Kulite’s pressure transducers are mounted, and three acceleration transducers are rigged on other blade. An iterative scheme for the fluid and for the blade is implemented in turn. For the phase of the flow and for the phase of the vibration, large eddy simulation (LES) and step-by-step integral method are employed, respectively. The comparison shows that the computational results are agreeable with the experimental measurements.