The EWG/VWG - test rig enables the investigation of indirect combustion noise. The major challenges in analyzing indirect combustion noise in aero-engines are the complexity of the noise generating mechanisms and the separation of direct and indirect noise.
While direct combustion noise arises in the primary combustion zone, indirect combustion noise, like entropy and vortex noise, is generated by the interaction of combustion chamber and turbine in aero-engines. The breakdown and allocation of these sound sources is therefore a crucial capacity for core noise research.
The EWG/VWG-test rig reduces the complexity of a combustor-turbine system by replacing the combustion chamber with generator modules producing either entropy (EWG) or vorticity (VWG) fluctuations in a tube flow under very controlled conditions.
The acceleration of these fluctuations (in entropy or vorticity) through a convergent-divergent nozzle, comparable to the nozzle guide vane (NGV) of a turbine stage, generates indirect noise which is detected by a microphone array downstream of the nozzle.
This test rig allows parameter studies on entropy and vortex noise and provides validation data for numerical simulations and analytical modeling approaches. The findings help to evaluate and predict the contribution of indirect combustion noise to the total noise emission of aero-engines.
Sketch of EWG / WWG
Specifications of the Test Rig