Combustion Generated Noise in Gas Turbine Combustors

Abstract

Experiments are conducted for the noise power and spectra emitted from a gas turbine combustor can exhausting to the atmosphere. The theory of combustion noise is applied to the results to determine the noise generating capability of the flame in the absence of reflecting can surfaces. The results show that for a fixed fuel (JP-4) the noise output is independent of fuel/air ratio for well stabilized can-type flames and heavily dependent on airflow while the spectra are dominated by the can acoustics, primarily through sound absorption by the liner. In an installed configuration the noise output depends heavily on the enclosure acoustics. For well stabilized can-type flames the equivalent unenclosed flame radiates with a thermoacoustic efficiency near 5 × 10−6, for air-flows of the magnitude used in this program. Scaling rules are presented for installed configurations.