The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 27, 2002
Filed:
Nov. 30, 2000
Man-Chun Tse, Brossard, CA;
Pratt & Whitney Canada Corp., Quebec, CA;
Abstract
A gas turbine engine fan assembly includes fan blades spaced axially from stator vanes inside an annular bypass duct. A plurality of perforated baffle plates are installed in the annular bypass duct downstream of the stator vanes. The perforated baffle plates extend in a generally axial direction and are unevenly, circumferentially spaced apart from one another to divide a major section of the annular bypass duct into a plurality of axial flow-path segments in an asymmetrical pattern to disrupt continuity, destroy a symmetrical pattern and absorb sound energy of a spinning mode of sound pressures imbedded in the air flow downstream of the stator vanes, without substantially affecting a thrust provided by the air flow when discharged from the bypass duct. The invention provides a solution for suppressing rearward noise propagation of a fan BPF tone and higher harmonics thereof through the annular bypass duct of a gas turbine engine, which contributes to the reduction of aircraft noises, particularly during take-off.