Impact of Future Low-Emissions Combustor Technology on Acoustic Scaling Laws

The overall goal of a recent research project at the Raytheon Technologies Research Center,
under National Aeronautics and Space Administration sponsorship, was to develop a first-ofits-kind database of detailed unsteady measurements characterizing noise sources of far-term
advanced low-emissions aero-combustors. The program addressed the need for fundamental
combustion-noise experiments which, in the near term, enable improvements to reduced-order
models for use in system level noise assessments at the preliminary design stage for advanced
air transport vehicles. In addition, optical measurement techniques were refined and validated
for usage at the higher pressures and temperatures relevant to future combustor designs. In
the long term, results from this program can be utilized to validate high-fidelity prediction
methods suited for detailed multi-disciplinary acoustics/emissions combustor design. This paper
concentrates on one aspect of the overall project, namely an examination of the legacy scaling
laws for broadband combustor noise.