Shock wave induced high cycle fatigue of variable guide vanes radial turbine blade

The shock wave located near the trailing edge of the nozzle can induce the pressure fluctuation on the surface of the rotor blade. However, the physical mechanism of the shock wave induced high cycle fatigue is ignored. A variable vane radial turbine, suffered the high cycle fatigue in the test, was investigated by the three-dimensional numerical method. The characteristic of the shock wave and pressure fluctuation on the surface of rotor induced by the guide vane gap leakage were analyzed in details. Threedimensional finite element analysis coupled with the results from unsteady simulation was used to perform modal analysis and structure analysis. The blade stress level and the symmetrically circulating stress are obtained. Results showed that the pressure fluctuation with large amplitude near the leading edge of the rotor blade, induced by the shock wave on the trailing edge of the nozzle, can resonance with the rotor blade vibration, and this phenomenon severely increases the risk of high cycle fatigue.