On the Application of a Harmonic Balance Method with a Volume Source Cooling Model to the Simulation of a Film-Cooled Turbine Stage

Kurzfassung

The application of Reduced Order Models (ROMs) in the simulation of complex, time-dependent flows in turbomachines provides a means to significantly reduce the cost, both in terms of preprocessing and computational overhead, of numerical simulations. In this work the development and combination of two ROMs for the simulation of the unsteady, time-periodic flow and heat transfer in a film-cooled turbine are presented. For the simulation of the unsteady flow an alternating frequency/time domain Harmonic Balance (HB) method is applied. To allow the efficient preprocessing and simulation of film-cooled blades a second, volume source based, ROM is incorporated into the underlying nonlinear solver of the HB method. Through the application of the volume source model the time consuming and error prone resolution and specification of individual cooling holes is no longer necessary. To validate the newly implemented volume source model a number of simple academic test cases are presented and analyzed in detail. Following the basic validation of the cooling model the approach is combined with the HB method to simulate the unsteady flow in the first one and half stages of a high-pressure turbine.