Important aspects for the low-noise design of future aero-engines are the accurate assessment of the propagation of combustion noise through the turbine stages and the detailed thermo-acoustic modeling of the combustion chamber system including acoustic boundary conditions at the turbine inlet guide vane. In order to promote the understanding of these issues, a dedicated test was set up in a high pressure turbine rig with an upstream acoustic excitation and two large microphone arrays upstream and downstream of the turbine stage capable to assess the modal content of the excited sound field up to the first blade passing frequency. Transmission and reflection characteristics have been obtained which suggest a low transmission of acoustic energy, but, at the same time, also a confined reflection of the acoustic energy at the stage. The data from experiments has been used to compare with numerical calculations and to validate a low order modeling tool. Satisfactory agreement has been found proving the capabilities of the numerical tools for future investigations.
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