US-12618381-B2 - Gas turbine exhaust nozzle noise abatement

Abstract

An exhaust nozzle for a gas turbine engine. The exhaust nozzle comprises a nozzle body having an upstream end axially spaced from a downstream end with respect to an axial centerline of the nozzle body, and a plurality of chevrons circumferentially spaced apart and extending downstream from the downstream end. Each chevron includes an inner wall radially spaced from an outer wall, a root and a tip axially spaced from the root. At least one chevron of the plurality of chevrons includes a first segment extending axially downstream from the root, a second segment extending axially downstream from the first segment, and a third segment extending axially downstream from the second segment to the tip. The inner wall extends along the first segment, the second segment, and third the segment. The first segment is distinguishable from the second segment and the second segment is distinguishable from the third segment.

Inventors

• Kishore Ramakrishnan
• Steven B. Morris
• Nikolai N. Pastouchenko
• Trevor Howard Wood

Assignees

• GENERAL ELECTRIC COMPANY

Dates

Publication Date

20260505

Application Date

20240131

Claims (20)

1. 1 . An exhaust nozzle of a gas turbine engine, the exhaust nozzle comprising: a nozzle body having an upstream end axially spaced from a downstream end with respect to an axial centerline of the nozzle body, and a plurality of chevrons circumferentially spaced apart and extending downstream from the downstream end, wherein each chevron includes an inner wall radially spaced from an outer wall, a root and a tip axially spaced from the root; wherein at least one chevron of the plurality of chevrons includes a first segment extending axially downstream from the root, a second segment extending axially downstream from the first segment, and a third segment extending axially downstream from the second segment to the tip, and wherein the inner wall extends along the first segment, the second segment and the third segment; wherein the first segment is distinguishable from the second segment and the second segment is distinguishable from the third segment; wherein the inner wall along the first segment has a radius that is constant with respect to the axial centerline from the root to a first inflection point, the inner wall along the second segment has an increasing radius from the first inflection point to a second inflection point, and the inner wall along the third segment has a decreasing radius from the second inflection point to the tip, wherein the inner wall at the root defines a root radius, and wherein the inner wall at the tip defines a tip radius that is less than the root radius; and wherein the outer wall of the at least one chevron includes a first outer wall segment that has a first increasing radius extending from the tip to a first outer wall inflection point and a second outer wall segment that has a second increasing radius extending from the first outer wall inflection point to an outer wall upstream end that extends beyond the downstream end of the nozzle body, and wherein the first outer wall inflection point is located between the second inflection point of the inner wall and the tip of the chevron.
2. 2 . The exhaust nozzle as in claim 1 , wherein the inner wall of the at least one chevron of the plurality of chevrons has a continuous radius of curvature between each of the first segment, the second segment, and the third segment.
3. 3 . The exhaust nozzle as in claim 1 , wherein the at least one chevron of the plurality of chevrons has a circumferential profile.
4. 4 . The exhaust nozzle as in claim 3 , wherein the circumferential profile has a constant curvature.
5. 5 . The exhaust nozzle as in claim 3 , wherein the circumferential profile has a non-varying curvature.
6. 6 . The exhaust nozzle as in claim 3 , wherein the circumferential profile has a variable curvature.
7. 7 . The exhaust nozzle as in claim 3 , wherein the circumferential profile has a curvature that varies azimuthally.
8. 8 . The exhaust nozzle as in claim 1 , wherein the first segment is disposed downstream from a throat of the exhaust nozzle, wherein the third segment at the tip extends into the exhaust nozzle a third segment distance, wherein the first segment at the root extends into the exhaust nozzle a first segment distance, and wherein the third segment distance is greater than the first segment distance.
9. 9 . The exhaust nozzle as in claim 1 , wherein an axial length of a first chevron of the plurality of chevrons is different from an axial length of a second chevron of the plurality of chevrons.
10. 10 . The exhaust nozzle as in claim 1 , wherein a portion of the outer wall is faired in upstream from the nozzle body downstream end, and wherein the outer wall has a variable slope between the faired in portion and the tip.
11. 11 . An aircraft, comprising: a fuselage, a wing and a turbofan engine, the turbofan engine including a turbine section and an exhaust nozzle disposed downstream from the turbine section, wherein the exhaust nozzle comprises: a nozzle body having an upstream end axially spaced from a downstream end with respect to an axial centerline of the nozzle body, and a plurality of chevrons circumferentially spaced apart and extending downstream from the downstream end, wherein each chevron includes an inner wall radially spaced from an outer wall, a root and a tip axially spaced from the root; wherein at least one chevron of the plurality of chevrons includes a first segment extending axially downstream from the root, a second segment extending axially downstream from the first segment, and a third segment extending axially downstream from the second segment to the tip, and wherein the inner wall extends along the first segment, the second segment and the third segment, wherein the first segment is distinguishable from the second segment and the second segment is distinguishable from the third segment; wherein the inner wall along the first segment has a radius that is constant with respect to the axial centerline from the root to a first inflection point, the inner wall along the second segment has an increasing radius from the first inflection point to a second inflection point, and the inner wall along the third segment has a decreasing radius from the second inflection point to the tip, wherein the inner wall at the root defines a root radius, and wherein the inner wall at the tip defines a tip radius that is less than the root radius; and wherein the outer wall of the at least one chevron includes a first outer wall segment that has a first increasing radius extending from the tip to a first outer wall inflection point and a second outer wall segment that has a second increasing radius extending from the first outer wall inflection point to an outer wall upstream end that extends beyond the downstream end of the nozzle body, and wherein the first outer wall inflection point is located between the second inflection point of the inner wall and the tip of the chevron.
12. 12 . The aircraft of claim 11 , wherein the at least one chevron of the plurality of chevrons has a circumferential profile.
13. 13 . The aircraft of claim 12 , wherein the circumferential profile has a constant curvature.
14. 14 . The aircraft of claim 12 , wherein the circumferential profile has a non-varying curvature.
15. 15 . The aircraft of claim 12 , wherein the circumferential profile has a variable curvature.
16. 16 . The aircraft of claim 12 , wherein the circumferential profile has a curvature that varies azimuthally.
17. 17 . The aircraft of claim 11 , wherein the first segment is disposed downstream from a throat of the exhaust nozzle, wherein the third segment at the tip extends into the exhaust nozzle a third segment distance, wherein the first segment at the root extends into the exhaust nozzle a first segment distance, and wherein the third segment distance is greater than the first segment distance.
18. 18 . The aircraft of claim 11 , wherein an axial length of a first chevron of the plurality of chevrons is different from an axial length of a second chevron of the plurality of chevrons.
19. 19 . The aircraft of claim 11 , wherein a portion of the outer wall is faired in upstream from the nozzle body downstream end, and wherein the outer wall has a variable slope between the faired in portion and the tip.
20. 20 . The aircraft as in claim 11 , wherein the inner wall of the at least one chevron of the plurality of chevrons has a continuous radius of curvature between each of the first segment, the second segment, and the third segment.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a divisional of and claims priority to U.S. application Ser. No. 17/964,097 entitled “Gas Turbine Exhaust Nozzle Noise Abatement”, filed Oct. 12, 2022, the entire disclosure of which is hereby expressly incorporated by reference herein. FIELD The present invention relates generally to gas turbine engines, and, more specifically, to reduction of gas turbine engine exhaust noise. BACKGROUND Gas turbine engines may be used for aircraft propulsion. Gas turbine engines generate propulsive thrust via a core engine that produces a stream of hot exhaust gases discharged from an exhaust nozzle into ambient air. The exhaust gases exit the exhaust nozzle at a high velocity, particularly during take-off operation of the aircraft. The high velocity exhaust stream may interact with the ambient air to produce substantial noise along the take-off path of the aircraft. BRIEF DESCRIPTION OF THE DRAWINGS A full and enabling disclosure of the present disclosure, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which refers to the appended figures, in which: FIG. 1 is a perspective view of an exemplary aircraft as may incorporate one or more embodiments of the present disclosure. FIG. 2 illustrates an exemplary turbofan gas turbine engine according to at least one embodiment of the present disclosure. FIG. 3 is an aft-facing-forward isolation view of a core engine including an exhaust nozzle according to an exemplary embodiment of the present disclosure. FIG. 4 is an enlarged view of an aft end of the core engine as shown in FIG. 3, according to an exemplary embodiment of the present disclosure. FIG. 5 is an enlarged perspective view of an exemplary chevron according to an exemplary embodiment of the present disclosure. FIG. 6 is a cross-sectioned side view of an exemplary chevron as shown in FIG. 5 according to various exemplary embodiments of the present disclosure. FIG. 7 is a cross-sectioned side view of an exemplary chevron as shown in FIG. 5 according to an exemplary embodiment of the present disclosure. FIG. 8 is a cross-sectioned side view of an exemplary chevron as shown in FIG. 5 according to an exemplary embodiment of the present disclosure. FIG. 9 is a forward-looking aft view of the chevron as shown in FIGS. 6, 7, and 8, according to an exemplary embodiment of the present disclosure. FIG. 10 is a forward-looking aft view of the chevron as shown in FIGS. 6, 7, and 8, according to an exemplary embodiment of the present disclosure. FIG. 11 is a forward-looking aft view of the chevron as shown in FIGS. 6, 7, and 8, according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION Reference will now be made in detail to present embodiments of the disclosure, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the disclosure. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other implementations. Additionally, unless specifically identified otherwise, all embodiments described herein should be considered exemplary. The singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. The term “at least one of” in the context of, e.g., “at least one of A, B, and C” refers to only A, only B, only C, or any combination of A, B, and C. A “segment” as used in this specification refers to a portion of an inner wall of a chevron measured along an overall axial length of the chevron. One segment is distinguished from another by a radial inflection or termination point measurable along the inner wall and with respect to an axial centerline of an exhaust nozzle to which a particular chevron is attached. Thus a “distinguishable segment” is defined between two axially spaced radial inflection or termination points. A “third stream” as used herein means a non-primary air stream capable of increasing fluid energy to produce a minority of total propulsion system thrust. The third stream may generally receive inlet air (air from a ducted passage downstream of a primary fan) instead of freestream air (as the primary fan would). A pressure ratio of the third stream may be higher than that of the primary propulsion stream (e.g., a bypass or propeller driven propulsion stream). The thrust may be produced through a dedicated nozzle or through mixing of an airflow through the third stream with a primary propulsion stream or a core air stream, e.g., into a common nozzle. In certain exemplary embodiments an operating temperature of the airflow through the