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:
May. 16, 1989
Filed:
Jul. 20, 1987
Asif A Syed, Loveland, OH (US);
General Electric Company, Cincinnati, OH (US);
Abstract
The Mach number M.sub.o of flow in the intake nozzle or bypass duct of a gas turbine aircraft engine is determined from the acoustic impedance of a Helmholtz resonator to an engine fan-stator sound source. Pressure measurements P.sub.1 (t) and P.sub.2 (t), made nonintrusively at the duct wall surface and resonator cavity bottom are subjected to Fourier analysis to give P.sub.1 (f) and P.sub.2 (f), and acoustic impedance for the flow is determined from a complex transfer function H.sub.12. Flow Mach number is then established using known acoustic impedance/Mach number correlation relationships or a stored look-up table. An alternative embodiment, utilizes a sound source mounted in the Helmholtz resonator bottom and determines Mach number by pressure measurements made at spaced locations on the resonator chamber wall.