Jet blade ejector nozzle

• US 6,662,548 B1
• Filed: 09/27/2000
• Issued: 12/16/2003
• Est. Priority Date: 09/27/2000
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Clark, Larry T.
• Primary Examiner(s): Gartenberg, Ehud
• Application Number:
  US09/671,870
• Time in Patent Office: 1,175 Days
• Field of Search: 602/04, 602/261, 602/62, 60/391.83, 181/213
• US Class Current: 60/204
• CPC Class Codes: F02K 1/386 mixing devices in the jet pipe, e.g. for mixing primary and secondary flow
• CPC Class Codes: F02K 1/40 Nozzles having means for dividing the jet into a plurality of partial jets or having an elongated cross-section outlet
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A jet engine assembly having a jet engine and an unsteady flow ejector. The unsteady flow ejector segregates the exhaust flow from the jet engine into a plurality of rotating high velocity, low density jets and a plurality of rotating low pressure voids. The low pressure voids are employed to entrain at least a portion of a secondary flow of air which is mixed with the jets to produce a mixed flow having a relatively higher flow rate and a relatively lower velocity than the exhaust flow. A method for attenuating the noise that is produced by the exhaust flow of a jet engine is also provided.

Claims

1. A method for reducing the noise emitted by a flow of exhaust from an outlet of a jet propulsion engine having a turbine with a plurality of turbine stages, the method comprising the steps of:

segregating the exhaust flow into a plurality of rotating high velocity, low density jets and a plurality of rotating low pressure voids; and

employing the low pressure voids to entrain at least a portion of a secondary flow of air, the jets and the entrained secondary flow mixing to produce a mixed flow having a relatively higher flow rate and a relatively lower velocity than the exhaust flow.

2. The method of claim 1, wherein the step of segregating the exhaust flow is performed with a free-spinning rotor mounted to the aft of the exhaust of the jet engine.

3. The method of claim 1, wherein the step of segregating the exhaust flow is performed with a rotor that is mounted to one of the plurality of turbine stages.

4. The method of claim 3, wherein the rotor has a rotational speed that is equal to a rotational speed of an associated one of the turbine stages.

5. The method of claim 1, wherein the rotor is disposed within a cowling assembly having a cowling member and at least one closure member, the cowling member defining an inlet aperture, the at least one closure member being selectively positionable between an open position permitting a flow of ambient air to the rotor and a closed position inhibiting the flow of ambient air to the rotor.

6. The method of claim 5, wherein before the step of employing the low pressure voids to entrain the secondary flow of air, the method includes the steps of:

determining a speed of the jet propulsion engine; and

if the speed of the jet propulsion engine is below a predetermined speed, positioning the closure member in the open position.

7. The method of claim 1, wherein the secondary flow includes a boundary-layer bleed flow from a supersonic inlet.

8. The method of claim 1, wherein the secondary flow includes an engine cooling air flow.

9. The method of claim 1, wherein the secondary flow includes a flow of bypass air, the bypass air flow being generated from a flow mismatch between a supersonic inlet flow and an engine intake flow.