Application of unsteady aerodynamics and aeroelasticity in heavy-duty gas turbines

Modern computer simulations can predict some aspects of the unsteady aerodynamic phenomena associated with turbomachinery blade rows. This allows analysts to investigate aeroelastic phenomena, such as flutter, and blade-row interactions, such as forced response and unsteady effects on performance. This paper describes tools and design processes used to numerically investigate unsteady aerodynamic phenomena in heavy-duty gas turbines. A linearized Navier-Stokes method from the DLR has been used to predict the aerodynamic damping of both compressor and turbine airfoils under a variety of operating conditions. Some of these predictions were validated with engine experience. Other CFD codes, including TRACE from the DLR and ITSM3D from the University of Stuttgart, have been used to predict blade-row interaction. This includes the prediction of forced response due to rotor-vane interaction and unsteady effects on performance. The effects of airfoil clocking, including the effects of cooling flow injection, have also been investigated.