抄録
Experimental investigations of acoustic excitation and noise propagation in turbomachines require specialized rigs with sophisticated instrumentation. As it remains challenging to integrate such measurements into a real engine, sub-scale test rigs are required with acoustically optimized boundary conditions to isolate acoustic sources. Thus, scaling approaches have to be applied to establish similarity. In the present work similarity parameters are derived and methods to geometrically scale machines while maintaining aeroacoustic similarity are proposed. The scaling approach is investigated using a 1.5-stage turbine test rig. Numerical simulations of the original and geometrically scaled rig are performed to validate similarity using both time and frequency domain methods to simulate aerodynamic and aeroacoustic effects. Transient blade pressures and the acoustic fields induced by blade-vane interaction show a good agreement between the two test cases. Aeroacoustic similarity could thus be achieved using the scaling approach presented which allows for better transferability of sub-scale tests.
