Modelling Turbine Acoustic Impedance

We quantify the sensitivity of turbine acoustic impedance to aerodynamic design parameters. Impedance boundary conditions are an influential yet uncertain parameter in predicting thermoacoustic stability gas combustors. extend semi-actuator disk model cambered blades, using non-linear time-domain computations vane and stage cascades with forcing for validation data. Discretising aerofoils into multiple disks improves reflection coefficient predictions, reducing error by up order magnitude compared a flat plate assumption. A parametric study designs analytical shows is weak function degree reaction polytropic efficiency. The strongest influence flow coefficient, followed axial velocity ratio Mach number. provide combustion engineer improved tools predict conditions, suggest most likely be compromised change coefficient.