A study on unsteady aerodynamic excitation forces on radial turbine blade due to rotor-stator interaction

摘要

It is important to predict the resonant vibration level for the design of a variable nozzle turbine. In this study, unsteady CFD analyses are conducted to investigate flow mechanism that causes aerodynamic excitation forces. As a result, it is found that excitation forces are affected by shock wave and clearance flow and can be modeled with a linear function of impeller inlet dynamic pressure and Mach number. Then resonant vibration level is calculated by the CFD and FEM, and compared with experimental data. It is validated that CFD results can be used for qualitative evaluation of excitation forces.