Patent ID: 7533534
Filing Date: 2009-05-19
Classification: F01D

Abstract:
1. A method of reducing far field low frequency noise created by a combustor of a gas turbine engine, the engine having, a compressor, the combustor being an annular combustor having an inside wall and an outside wall, and a turbine, the engine having a centreline axis and defining an annular gas path adapted to guide an annular flow of hot gas from the annular combustor, through a nozzle guide vane ring to the turbine, the method comprising: emitting a plurality of jets of compressed air from an inner shroud of the nozzle guide vane ring downstream of a combustor exit annular flow of hot gas upstream of the turbine in a direction substantially perpendicular to the flow of gas in the gas path and adjacent an exit of the annular combustor to introduce turbulence into the flow substantially downstream of the annular combustor and equalize a temperature distribution of the flow, the turbulence in the hot gas flow resulting in a decoupling between sound attenuation and pressure fluctuation within the turbine and sound attenuation and pressure fluctuations in the combustor.