USH500H - Exhaust nozzle flap assembly - Google Patents

Exhaust nozzle flap assembly Download PDF

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Publication number
USH500H
USH500H US07/019,996 US1999687A USH500H US H500 H USH500 H US H500H US 1999687 A US1999687 A US 1999687A US H500 H USH500 H US H500H
Authority
US
United States
Prior art keywords
flap
exhaust gas
sidewall
pivot axis
flaps
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US07/019,996
Other languages
English (en)
Inventor
Claude R. Stogner
William M. Madden
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
US Air Force
Original Assignee
US Air Force
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by US Air Force filed Critical US Air Force
Priority to US07/019,996 priority Critical patent/USH500H/en
Assigned to UNITED TECHNOLOGIES CORPORATION reassignment UNITED TECHNOLOGIES CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: MADDEN, WILLIAM M., STOGNER, CLAUDE R.
Priority to EP88630029A priority patent/EP0281494A1/fr
Priority to JP63045689A priority patent/JPS63235652A/ja
Priority to KR1019880002118A priority patent/KR880010230A/ko
Priority to CN198888101072A priority patent/CN88101072A/zh
Assigned to UNITED STATES OF AMERICA, THE, AS REPRESENTED BY THE SECRETARY OF THE AIR FORCE reassignment UNITED STATES OF AMERICA, THE, AS REPRESENTED BY THE SECRETARY OF THE AIR FORCE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: UNITED TECHNOLOGIES CORPORATION
Application granted granted Critical
Publication of USH500H publication Critical patent/USH500H/en
Abandoned legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02K—JET-PROPULSION PLANTS
    • F02K1/00—Plants characterised by the form or arrangement of the jet pipe or nozzle; Jet pipes or nozzles peculiar thereto
    • F02K1/06—Varying effective area of jet pipe or nozzle
    • F02K1/12—Varying effective area of jet pipe or nozzle by means of pivoted flaps
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C15/00—Attitude, flight direction, or altitude control by jet reaction
    • B64C15/02—Attitude, flight direction, or altitude control by jet reaction the jets being propulsion jets
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02K—JET-PROPULSION PLANTS
    • F02K1/00—Plants characterised by the form or arrangement of the jet pipe or nozzle; Jet pipes or nozzles peculiar thereto
    • F02K1/06—Varying effective area of jet pipe or nozzle
    • F02K1/12—Varying effective area of jet pipe or nozzle by means of pivoted flaps
    • F02K1/1207—Varying effective area of jet pipe or nozzle by means of pivoted flaps of one series of flaps hinged at their upstream ends on a fixed structure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02K—JET-PROPULSION PLANTS
    • F02K1/00—Plants characterised by the form or arrangement of the jet pipe or nozzle; Jet pipes or nozzles peculiar thereto
    • F02K1/06—Varying effective area of jet pipe or nozzle
    • F02K1/12—Varying effective area of jet pipe or nozzle by means of pivoted flaps
    • F02K1/1223—Varying effective area of jet pipe or nozzle by means of pivoted flaps of two series of flaps, the upstream series having its flaps hinged at their upstream ends on a fixed structure and the downstream series having its flaps hinged at their upstream ends on the downstream ends of the flaps of the upstream series
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02K—JET-PROPULSION PLANTS
    • F02K1/00—Plants characterised by the form or arrangement of the jet pipe or nozzle; Jet pipes or nozzles peculiar thereto
    • F02K1/54—Nozzles having means for reversing jet thrust
    • F02K1/56—Reversing jet main flow
    • F02K1/62—Reversing jet main flow by blocking the rearward discharge by means of flaps
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T50/00—Aeronautics or air transport
    • Y02T50/60—Efficient propulsion technologies, e.g. for aircraft

Definitions

  • the present invention relates to a flow diverting flap assembly in a gas turbine engine exhaust nozzle arrangement.
  • flaps to divert normally axially flowing exhaust gases from a propulsion gas turbine engine in an aircraft application.
  • flaps are typically pivoted or otherwise positioned to selectably divert at least a portion of the exhaust gases to provide thrust vectoring for increased maneuverability and/or lift.
  • such vectoring exhaust nozzles and flaps are desirably designed to be relatively light in weight as compared to non-aircraft structures subject to similar pressure or stress loading.
  • a vectoring exhaust nozzle for a gas turbine engine is provided with at least one flap assembly for diverting the exhaust gas flow.
  • the flap assembly includes a first flap pivotable about a pivot axis oriented transversely with respect to the engine centerline axis and spaced apart therefrom.
  • the first flap further includes a pair of opposite sidewall disks, secured to the span ends of the first flap which is supported therebetween in a cantilever relationship.
  • the assembly according to the present invention induces a resultant moment at each of the span ends of the first flap through the corresponding sidewall disk due to the force of the internal exhaust gas pressure on the inward facing disk surfaces.
  • the resultant moments oppose the midspan bending moment created in the first flap by the pressure of the exhaust gas thereon, reducing the deflection of the first flap midspan from that of a simply supported flap.
  • This reduction in deflection is further limited in the case of a nozzle having a second, semi-cylindrical flap disposed outward of the first flap and pivotable about a common pivot axis therewith.
  • This arrangement particularly well suited for nozzles wherein the first flap is pivotable into a blocking orientation with respect to the axially flowing exhaust gases, provides support to the first flap via two thrust bearings disposed between the flaps and proximate the first flap span ends.
  • the nested two flap assembly provides a structure which is limited by the stresses induced in the individual components rather than the maximum relative deflection which can be accommodated.
  • FIG. 1 shows a section of an exhaust nozzle for a gas turbine enqine taken in the plane of the engine centerline and showing the arrangement of the flaps therein.
  • FIG. 2 shows a spanwise section of the flap assembly according to the present invention.
  • FIGS. 3a-d show a free body diagram of a simply supported flap and the resulting spanwise variation in shear moment and flap deflection.
  • FIGS. 4a-d show a free body diagram of the diverter flap from a flap assembly according to the present invention and the resulting spanwise variation in flap shear, moment, and deflection.
  • FIG. 1 shows a sectional view of an exhaust nozzle 10 taken through the centerline 12 of a gas turbine engine 14 shown in phantom.
  • the nozzle 10 is of the 2-D type wherein the typically circular engine exhaust is conducted into a rectangular flow passage by a transition section 16 disposed at the forward end of the nozzle 10.
  • the nozzle 10 further includes a pair of spaced apart, lateral sidewalls, one of which 18 is shown in FIG. 1 and upper and lower flap assemblies 20, 22 which respectively define portions of the upper and lower nozzle gas flow path.
  • the flap assemblies 20, 22 comprise first flaps 24, 26 which are oriented spanwisely so as to extend transversely across the axially flowing gas stream 8.
  • the first flaps 24, 26 are each pivotable about a corresponding pivot axis 28, 30 whereby the flaps 24, 26 may be selectably positioned to divert the exhaust gases 8 for thrust vectoring or outlet gas velocity regulation.
  • first flaps 24, 26 are secured at the span ends thereof to corresponding sidewall disks 32, 34 which are mounted substantially flush with the corresponding nozzle sidewall 18 and define therewith a portion of the lateral exhaust gas flow boundary.
  • FIG. 1 An aftward pair of divergent flaps 36, 38 are shown in FIG. 1 for the purpose of fully disclosing the environment within which the flap arrangement according to the present invention is utilized.
  • the divergent flaps 36, 38 are positioned independently of the first flaps 24, 26 and function to direct and expand the exiting exhaust gases as required by the current engine and aircraft operating conditions.
  • the exhaust nozzle 10 includes a pair of second flaps 40, 42 which are each semicircular and disposed both outward and adjacent to the respective first flaps 24, 26.
  • the second flaps 40, 42 control the admission of the exhaust gases 8 into corresponding reversing gas flow ducts 44, 46.
  • the first flaps 24, 26 are rotated into the exhaust gas flow 8 until both are oriented nearly perpendicular to the engine centerline 12 at which time the second flaps 40, 42 are rotated aftward for admitting the engine exhaust gases 8 into the reversing ducts 44, 46 whence the diverted exhaust gases are directed by the corresponding cascade of adjustable vanes 48, 50.
  • the internal differential pressure may be 50 psi (345 kPa) or higher depending on the operating configuration.
  • the gas path defining structure, including the sidewalls 18, sidewall disks 32, 34, and flaps 24, 26, 40, 42, must withstand this elevated pressure loading without overstressing the materials or structure and without experiencing excessive deflection which may result in interference between moving components or other undesirable effects.
  • FIGS. 3a-d illustrate the effect of such high pressure loadings on a simply supported flap 26' of the prior art.
  • FIG. 3a is a free diagram showing a uniform static pressure load 52 distributed over the span of the prior art flap 26' and counterbalanced by two equal reactive forces 54, 55 at the span ends of the flap 26'.
  • FIG. 3b is a graphic representation of the shear force present in the flap 26' over the span length L. This diagram is typical for a simply supported, uniformly loaded beam or the like.
  • FIG. 3c represents the variation of the moment in the flap 26' over the span length L.
  • the moment is 0 at the span ends of the flap 26' as is consistent with simply supported beam structures, rising to a maximum at the midspan, L/2, which coincides with the point of maximum deflection 60.
  • such behavior is typical for simply supported structures such as the prior art flap 26'.
  • sucn flap structures 26' may experience an undesirably large midspan deflection resulting from the gas static pressure load without concomitantly experiencing an overstress in any part of the structure of the flap 26'.
  • deflection-limited require such simply supported flaps to be strengthened to resist such deflection, typically by adding heavier or stiffer material to the flap structure, increasing the cross sectional moment of inertia of the flap, or both.
  • Such solutions while effective in reducing the magnitude of the maximum deflection of a simply supported flap, add size and/or weight to the flap component thereby reducing the attractiveness of such designs for high performance aircraft applications.
  • FIG. 2 shows a sectional view of a first flap 26 taken in the plane of the pivot axis 30.
  • the first flap 26 may be incorporated in an exhaust nozzle 10 either singly or as one of a pair of symmetric flap assemblies 20, 22 as shown in FIG. 1.
  • a flap 26 is shown cantilevered between spaced apart, opposite facing sidewall disks 34, 35 which in turn are pivoted about the pivot axis 30 which is in turn oriented transversely with respect to the engine axis 12 and spaced apart therefrom.
  • the static pressure loading 62 caused by the elevated pressure exhaust gas in the nozzle acts to force the sidewall disks 34, 35 laterally outward as well as to push the flap 26 downward as shown in FIG. 2.
  • the sidewall disks 34, 35 are supported by bearing structures 64, 66 which are in turn simply supported at 68 by the nozzle static structure (not shown).
  • the first flap 26 is further offset a distance indicated at 70 with respect to the pivot axis 30 for providing a reactive moment at the span ends of the flap 26 due to the outward pressure force on the integral sidewall disks 34, 35.
  • This offset 70 may be increased or decreased by the nozzle designer to provide the desired magnitude of reactive moment at the span ends to reduce the maximum mid span flap deflection as discussed hereinbelow.
  • FIGS. 4a-d The effect of the reactive moments 72, 73 are illustrated in FIGS. 4a-d wherein 4a shows a free body diagram of the first flap 26 according to the present invention.
  • the flap 26 is supported in a cantilever relationship at the span ends thereof which are resolved in FIG. 4a into pairs of equal reactive forces 74, 75 and moments 72, 73.
  • the uniform flap pressure loading 62 is also shown.
  • FIG. 4b shows the variation of the shear force over the length of the flap span L and is similar to that of the simply supported prior art flap as shown in FIG. 3b.
  • FIG. 4c illustrates the effect of the resultant moments 72, 73 imposed on the span ends of the flap 26 in the integral disk-flap-disk arrangement according to the present invention.
  • the negative moments imposed at the span ends directly reduce the maximum moment 76 occurring at the flap midspan.
  • the modified moment distribution in the flap 26 according to the present invention alters the deflection mode of the flap as shown in FIG. 4d, providing a substantial reduction 78 in the maximum deflection of the flap.
  • the crosswise moment of inertia of both the prior art flap 26' and the flap 26 according to the present invention are equivalent.
  • the first flap assembly according to the present invention achieves a reduced maximum deflection under gas static pressure loading as compared to a simply supported flap of the prior art.
  • the flap arrangement according to the present invention is able to achieve a desired maximum deflection with a comparatively lightweight structure.
  • FIG. 2 A further feature of the flap assembly according to the present invention, particularly suited for the two flap, nested assembly 20, 22 as shown in FIG. 1, is illustrated in FIG. 2 wherein the second, semi-cylindrical flap structure 42 is shown disposed adjacent the first flap 26 and rotatable about a common pivot axis 30 therewith.
  • the arrangement according to the present invention includes a pair of thrust bearings 80, 81 disposed proximate the span ends of the first flap 26 for preventing relative movement between the respective span ends of the first and second flaps 26, 42.
  • the linking of the first and second flaps 26, 42 in this fashion creates a structure with a greater spanwise rigidity and crosswise moment of inertia.
  • the nested, linked flaps 26, 42 thus cooperate to strengthen the combined structure and better enable each flap component to resist deflection under static pressure loading from the exhaust gas.
  • static pressure loading attempts to induce an outward bowing of the individual flap members perpendicular to the individual flap spans resulting in the thrust bearings 80, 81 imposing a compressive force on the first flap 26 and a tensile force on the second flap 42.
  • the second flap 42 is typically designed as a thin section with a relatively small cross span moment of inertia, it is better suited to withstand a combined bending and tensile stress as opposed to merely a bending stress which would result if the bearings 80, 81 allowed free spanwise translation of the second flap span ends.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Supercharger (AREA)
  • Control Of Turbines (AREA)
  • Turbine Rotor Nozzle Sealing (AREA)
US07/019,996 1987-02-27 1987-02-27 Exhaust nozzle flap assembly Abandoned USH500H (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US07/019,996 USH500H (en) 1987-02-27 1987-02-27 Exhaust nozzle flap assembly
EP88630029A EP0281494A1 (fr) 1987-02-27 1988-02-18 Volet pour une tuyère de propulsion variable
JP63045689A JPS63235652A (ja) 1987-02-27 1988-02-26 ガスタービンエンジンの排気ノズル用フラップ組立体
KR1019880002118A KR880010230A (ko) 1987-02-27 1988-02-27 배출 노즐 날개판 조립물
CN198888101072A CN88101072A (zh) 1987-02-27 1988-02-27 排气喷管调节片总成

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US07/019,996 USH500H (en) 1987-02-27 1987-02-27 Exhaust nozzle flap assembly

Publications (1)

Publication Number Publication Date
USH500H true USH500H (en) 1988-08-02

Family

ID=21796188

Family Applications (1)

Application Number Title Priority Date Filing Date
US07/019,996 Abandoned USH500H (en) 1987-02-27 1987-02-27 Exhaust nozzle flap assembly

Country Status (5)

Country Link
US (1) USH500H (fr)
EP (1) EP0281494A1 (fr)
JP (1) JPS63235652A (fr)
KR (1) KR880010230A (fr)
CN (1) CN88101072A (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5188292A (en) * 1991-06-28 1993-02-23 The United States Of America As Represented By The Secretary Of The Air Force Thermal shields for rotating members in a gas flow path
US10318904B2 (en) 2016-05-06 2019-06-11 General Electric Company Computing system to control the use of physical state attainment of assets to meet temporal performance criteria

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2393941B (en) 1990-01-26 2004-09-29 Rolls Royce Plc Vectorable variable area nozzle
US7669785B2 (en) * 2006-04-24 2010-03-02 The Boeing Company Integrated engine exhaust systems and methods for drag and thermal stress reduction
FR3082238A1 (fr) * 2018-06-11 2019-12-13 Airbus Operations Tuyere primaire d'un conduit d'ejection primaire d'une turbomachine
CN114562382B (zh) * 2022-01-13 2024-01-30 中国航发沈阳发动机研究所 一种作动筒短距可调引气喷管

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1435946A (en) * 1973-02-17 1976-05-19 British Aircraft Corp Ltd Efflux conduits for aircraft jet propulsion engines
GB2155552B (en) * 1981-02-24 1986-02-26 Rolls Royce Adjustable jet propulsion nozzle
US4690329A (en) * 1984-11-02 1987-09-01 United Technologies Corporation Exhaust nozzle coupled with reverser exhaust door
US4753392A (en) * 1984-11-02 1988-06-28 United Technologies Corporation Two dimensional gas turbine engine exhaust nozzle

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5188292A (en) * 1991-06-28 1993-02-23 The United States Of America As Represented By The Secretary Of The Air Force Thermal shields for rotating members in a gas flow path
US10318904B2 (en) 2016-05-06 2019-06-11 General Electric Company Computing system to control the use of physical state attainment of assets to meet temporal performance criteria
US10318903B2 (en) 2016-05-06 2019-06-11 General Electric Company Constrained cash computing system to optimally schedule aircraft repair capacity with closed loop dynamic physical state and asset utilization attainment control

Also Published As

Publication number Publication date
KR880010230A (ko) 1988-10-07
JPS63235652A (ja) 1988-09-30
EP0281494A1 (fr) 1988-09-07
CN88101072A (zh) 1988-09-07

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AS Assignment

Owner name: UNITED TECHNOLOGIES CORPORATION,CONNECTICUT

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:STOGNER, CLAUDE R.;MADDEN, WILLIAM M.;REEL/FRAME:004687/0347

Effective date: 19870222

AS Assignment

Owner name: UNITED STATES OF AMERICA, THE, AS REPRESENTED BY T

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:UNITED TECHNOLOGIES CORPORATION;REEL/FRAME:004888/0507

Effective date: 19880321

Owner name: UNITED STATES OF AMERICA, THE, AS REPRESENTED BY T

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST. SUBJECT TO LICENSE RECITED;ASSIGNOR:UNITED TECHNOLOGIES CORPORATION;REEL/FRAME:004888/0507

Effective date: 19880321

STCF Information on status: patent grant

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