There is a demand for Modern Heavy Duty Gas Turbines (HDGT) to provide greater MW power output with higher efficiency. This trend leads to longer and slimmer turbine last stage blades with exposure to higher aerodynamic loadings. As a result, they are more prone to flutter risks. Turbine flutter risks must be addressed during the design phase and this requires the accurate prediction of the flutter boundary and the aero damping ratios with quantified uncertainties.
Numerical simulations, based on Computational Fluid Dynamics (CFD), of a two-passage linear turbine cascade were carried out. The results are presented in this paper aimed to study aspects of flutter. A time-linearized Navier–Stokes approach was applied to predict the aeroelastic response. Simulations were carried out for Mach numbers ranging from 0.4 to 1.2. The objective of this study is to quantify the aero damping prediction uncertainty.
CFD results showed successful prediction of the transonic flutter boundary. The predicted aero work was compared with the experimental data and good agreements were demonstrated for both the subsonic and supersonic flows. The steady and unsteady surface pressures on the test rig sidewalls, predicted by CFD, were then compared with the test data in great detail. Limitations of the linear approach are also discussed.