Patent ID: 7648330
Filing Date: 2010-01-19
Classification: F02C,F05D,Y02T

Abstract:
1. A method of noise control for a plurality of blades mounted on a disc or hub to rotate within a housing incorporating a duct having an acoustic liner whereby when rotating those blades cause noise, the method comprising; a) determining a noise attenuation frequency spectrum within the housing and any attenuation means associated with that of the housing, the noise frequency spectrum having frequencies of higher attenuation and frequencies of lower attenuation; b) determining a noise frequency spectrum at the rotor face for the plurality of blades when specifically rotated, the noise frequency spectrum having frequencies of higher noise level and frequencies of lower noise level; and, c) rearranging specific blade positions upon the disc or hub to increase the number of frequencies of higher noise level to match the frequencies of higher attenuation for greater noise control.