Method and device for reducing the noise of turbo-machines

US4199295A · kind A · utility

Assignee

• Societe Nationale d'Etude et de Construction de Moteurs d'Aviation - S.N.E.C.M.A · FR

Inventors

• Pierre M. Raffy · Melun, FR
• Pierre A. Andre · Paris, FR
• Jean-Pierre Y. B. Girault · Dammarie-les-Lys, FR
• Gerhard Richter · Kreuztal, DE
• Jean-Claude Thevenin · Vélizy-Villacoublay, FR

Key dates

• Filing date: Nov 7, 1977
• Grant date: Apr 22, 1980
• Expiry date: Nov 7, 1997

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F05D2260/962
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

A device for reducing the noise generated by the blades of at least one r of rotor blades in a turbo-machine by the production of a counter-noise of opposed phase. This is achieved by injection of jets of fluid under pressure through orifices borne by the rotor located near to the periphery of the blades, and the flow of the fluid is modulated at a frequency which is a whole number multiple of the rotational frequency of the rotor shaft. Regulation of phase of the modulated injected fluid is carried out in such a manner that the acoustic waves generated by the injected fluid are substantially in opposition, with respect to phase, to those of the noise to be reduced.