Estimation of Burner-Can Induced Excitation Response of an Industrial Low Pressure Turbine Blade: Validation Against Prototype Test Data Available to Purchase

Discovering vibration problems after engine prototype tests translates in increased costs and limited re-design space. For this reason numerical tools are more and more being applied to help taking correct decision in the early design. This paper presents the estimation of the vibration levels induced by hot-streaks from burner-cans in the last blade of an industrial gas turbine. The aerodynamic forcing was obtained from full wheel time marching unsteady computational fluid dynamics calculation. The results are compared with a previous calculation of a scaled sector model. Determination of different sources of damping is achieved by the use of an unsteady aerodynamics harmonic solver and a friction damping harmonic balance method. Results show that the fatigue risk due to the first burner-can harmonic could be predicted with a fairly good accuracy from both scaled and full wheel model when compared with the strain gage prototype test data. The presence of various engine orders in the test spectral maps are commented and related to the calculations.