A Study of Large Aero-Engine Combustor Noise

Noise-Source Separation Using Internal and Far-Field Sensors for a Full-Scale Turbofan Engine

“…This is the opposite situation to that of the argument in Ref. 32, where it is assumed that direct noise is dominant for frequencies less than 100 Hz and entropy (indirect) noise peaks at 200 Hz and is dominant at higher frequencies. E. Combustion-Noise Narrow-Band Results Figure 4 shows the far-field narrow-band results of the source separation procedures for the flight-idle condition of 48 percent corrected fan speed in the 130 o direction.…”

“…Harper-Bourne et al, 32 in their combustor-noise study of the large ANTLE research engine, have suggested that the difference between the two-signal results using combustor-internal and exit-pipe sensors, respectively, can be explained on the basis of the presence of both direct and indirect combustion noise. They argue that the first method educes only direct combustion noise, whereas the second one detects the total (direct + indirect) combustion noise.…”

Core noise - Identification of broadband noise sources of a turbo-shaft engine

“…In order to approach this goal, internal instrumentation of the engine is required. In earlier investigations few sensors were installed close to the combustor in order to separate the combustor contributions in the far-field spectra 4 . A very comprehensive study was carried out by and Hultgren and Miles 8 .…”

Modelling of Sound Generation by Turbulent Reacting Flows

“…However this contribution lies in the low frequency range and it is only weakly attenuated by liners inside the nacelle duct. It is also known that the separation between combustion and jet noise components is difficult to make in practice, as shown by Hoch et al [41], Muthukrishnan et al [59], Parthasarathy et al [62] or more recently by Harper-Bourne et al [39] and Blacodon [6]. Noise induced by combustion actually originates from two distinct processes.…”