Aerodynamic and aeroelastic computations of a last stage steam turbine using harmonic balance methods

Abstract

Numerical aerodynamic and aeroelastic assessment using the harmonic balance method has been applied to a 3D last stage steam turbine open test case, which is representative of the aerodynamic characteristics of transonic industrial steam turbine blading. The benchmark results showed reasonable agreement with previous research and numerical validation efforts from both academia and industry.In addition, it has been demonstrated that a large part of the numerical design workflows of modern last stage turbine blading, including steady-state aero performance calculation using mixing plane, transient blade row interaction, aerodynamic damping predictions, and accounting for complex non-axisymmetric geometric features such as the exhaust hood, can be performed efficiently using single passage models. Further investigation and parametric studies are needed regarding acoustic interactions and turbulence modeling, to contribute to an even more comprehensive validation of the test case.