Mixed flow augmentor incorporating a fuel/air tube

• US 4,686,826 A
• Filed: 05/14/1980
• Issued: 08/18/1987
• Est. Priority Date: 05/14/1980
• Status: Expired due to Term

• Current Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Original Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Inventors: Larson, Harold A., Pfefferle, Richard A., Koshoffer, John M.
• Primary Examiner(s): BENTLEY, STEPHEN
• Application Number:
  US06/149,792
• Time in Patent Office: 2,652 Days
• Field of Search: 60/737, 60/749, 60/261, 60/262
• US Class Current: 60/762
• CPC Class Codes: F02K 1/386 mixing devices in the jet pipe, e.g. for mixing primary and secondary flow
• CPC Class Codes: F23R 3/20 incorporating fuel injection means
• CPC Class Codes: F23R 3/22 movable, e.g. to an inoperative position; adjustable, e.g. self-adjusting
• CPC Class Codes: Y02E 20/34 Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery

Abstract

In a turbofan jet engine, having a circumferentially rotatable mixer segment capable of orienting the afterburner ignitors and flameholders into the path of either the exhaust gases or bypass air, a fuel-air transfer apparatus for capturing, transporting and the releasing of an enriched fuel-air concentration from the fuel spray bars, on the stationary structure of the jet engine, to the afterburner ignitors and flameholders rigidly attached at the rear of the rotatable segment of the mixer. The enriched fuel-air mixture is transported between a location of reliable fuel availability, through a region of highly turbulent gas flow and is thereafter released while still in an enriched concentration immediately upstream of the ignitors and flameholders, facilitating ignition and sustained operation of the afterburner. The transfer of the fuel-air mixture with the exhaust gases in a confining apparatus precludes the necessity for transferring fuel, by flexible attachment or other means, between the stationary jet engine structure and the rotatable segment of the mixer, upon which the ignitors and flameholders are mounted, while insuring an appropriate fuel-air mixture for ignition and operation of the afterburner.

Claims

1. In a turbofan jet engine having a rotatable mixer in the gas stream of said engine for mixing fuel and air, said mixer comprising a radially sectored structure defining a plurality of axially extending troughs, a fuel source attached to the stationary structure of said engine upstream of said mixer, and an ignitor and flameholder downstream of said mixer, an improvement comprising:

a transfer tube disposed in each alternate trough and rigidly attached to said mixer, each tube having an inlet near an upstream end of said mixer and an outlet near a downstream end of said mixer for capturing a fuel-rich fuel-air mixture from said source, transporting said mixture through said mixer and releasing said mixture at the downstream end of said mixer in the immediate vicinity of said ignitor and flameholder, the respective inlet of each said tube being aligned to capture substantially all the fuel released from said source at said respective inlet.

2. In a turbofan jet engine having a rotatable mixer in the gas stream of said engine for mixing fuel and air, said mixer comprising a radially sectored structure defining a plurality of axially extending troughs, a fuel source attached to the stationary structure of said engine upstream of said mixer, and an ignitor and flameholder downstream of said mixer, an improvement comprising:

a transfer tube disposed in each alternate trough and rigidly attached to said mixer, each tube having an inlet near an upstream end of said mixer and an outlet near a downstream end of said mixer for capturing a fuel-rich fuel-air mixture from said source, transporting said mixture through said mixer and releasing said mixture at the downstream end of said mixer in the immediate vinicity of said ignitor and flameholder, the respective inlet of each said tube being aligned with said fuel source to capture substantially all the fuel released from said source at said respective inlet and the respective outlet of each said tube being aligned with said flameholder and ignitor to release the fuel-air mixture directly thereon.