Power plants – Reaction motor – Method of operation
Reexamination Certificate
2000-09-14
2001-10-02
Kim, Ted (Department: 3746)
Power plants
Reaction motor
Method of operation
C239S127300, C239S265170, C060S266000
Reexamination Certificate
active
06295805
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates generally to the field of aircraft propulsion and, more particularly, to an exhaust induced ejector nozzle system and method.
BACKGROUND OF THE INVENTION
Aircraft gas turbine engines generally employ exhaust or ejector nozzles having flaps and seals that are used to contain exhaust flow from the engine and use thrust to propel the aircraft. The nozzle is generally designed for supersonic operation and includes a convergent portion for accelerating the exhaust airflow at the nozzle throat and a divergent portion for accelerating the exhaust airflow supersonically.
Cooling of the nozzle is generally required to provide thermal protection to the nozzle and fire protection to the aircraft engine. Cooling is generally provided by diverting a source of nacelle or ambient air around the aircraft engine and into the divergent portion of the nozzle using an ejector. The ejector is generally located in the divergent portion of the nozzle such that the exhaust airflow, being at a higher velocity and higher pressure, draws lower velocity and lower pressure cooling air into the nozzle to cool the nozzle.
Preventing the exhaust airflow from escaping the aircraft engine and migrating into a nacelle where the accumulated exhaust airflow may combust or cause a fire or explosion is also important. The ejector reduces the likelihood of the exhaust airflow migrating into a nacelle by withdrawing air in the nacelle into the divergent portion of the nozzle.
However, present nozzles suffer from several disadvantages. For example, airflow from the nacelle is strongly dependent on the nacelle inlet characteristics, the nozzle schedule, the ejector characteristics, and the flight envelope of the aircraft. Thus, it is generally difficult to provide all the required nacelle airflow in all regions of the flight envelope without having a negative impact on aircraft and/or engine performance or negative impacts to airframe strength. For example, particular flight envelope conditions may result in a reduced or negative pressure differential between the nacelle and the divergent portion of the nozzle, thereby reducing or reversing the airflow in the nacelle creating a fire hazard.
SUMMARY OF THE INVENTION
Accordingly, a need has arisen for an improved ejector nozzle system and method that provides improved nacelle airflow while being less sensitive to a flight envelope of an aircraft. The present invention provides an improved ejector nozzle system and method that addresses shortcomings of prior ejector nozzle systems and methods.
According to one embodiment of the invention, an ejector nozzle includes a convergent portion and a divergent portion disposed downstream from the convergent portion. The ejector nozzle also includes an ejector having an outlet disposed within the divergent portion. The ejector is operable to provide entrainment of a nacelle airflow from a nacelle airflow area into the divergent portion. The ejector nozzle further includes a convergent ejector extending between the convergent portion and the nacelle airflow area. The convergent ejector is operable to draw a portion of an exhaust airflow into the nacelle airflow area to increase a flow rate of the nacelle airflow.
According to another embodiment of the invention, a method for enhanced ejector nozzle cooling includes receiving a nacelle airflow into a nacelle airflow area. The method also includes entraining the nacelle airflow from the nacelle airflow area into a divergent portion of the ejector nozzle using an exhaust airflow. The method further includes enhancing a flow rate of the nacelle airflow by drawing a portion of the exhaust flow into a convergent ejector. The convergent ejector extends between a convergent portion of the ejector nozzle and the nacelle airflow area.
The invention provides several technical advantages. For example, in one embodiment of the invention, exhaust airflow flowing through the convergent ejector provides additional motive flow or pumping to increase the flow rate of the nacelle airflow at all flight conditions. Additionally, the ejector nozzle of the present invention provides additional nacelle airflow without tapping into bleed air as a source of energy.
Other technical advantages will be readily apparent to one skilled in the art from the following figures, descriptions, and claims.
REFERENCES:
patent: 3370794 (1968-02-01), Drewry et al.
patent: 3575260 (1971-04-01), Urguhart
patent: 3726091 (1973-04-01), Tontini
patent: 5255849 (1993-10-01), Mayer et al.
patent: 5435127 (1995-07-01), Luffy et al.
patent: 5577381 (1996-11-01), Eigenbrode et al.
patent: 5586431 (1996-12-01), Thonebe et al.
patent: 5720434 (1998-02-01), Vdoviak et al.
patent: 5761899 (1998-06-01), Klees
patent: 5884843 (1999-03-01), Lidstone et al.
patent: 5996936 (1999-12-01), Mueller
Catt Jeffrey A.
Lackey Jesse R.
Baker & Botts L.L.P.
Kim Ted
Lockheed Martin Corporation
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