Far Field Combustion Noise From Full-Scale Flight Tests

This paper presents the development of a new combustor noise prediction process for direct combustion noise. This process has been developed based on data from both the Quiet Technology Demonstrator 2 (QTD2) and the NASA/Boeing Propulsion Airframe Aeroacoustics & Aircraft System Noise (PAA/ASN) full-scale flight tests. The combustor noise prediction model development steps are outlined, and the framework is provided. The most significant findings of this work are how combustor noise has reduced over time and a new method of the correlation of combustor noise. Using the framework, the proposed model has been developed, which reduces the overall combustor noise prediction error on a power-level basis from + ~10-20 dB to +/- 3-5 dB. This will greatly improve the ability to predict both current and future aircraft concepts.