US3527318A - Jet-engine silencer - Google Patents

Jet-engine silencer Download PDF

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Publication number
US3527318A
US3527318A US845849A US3527318DA US3527318A US 3527318 A US3527318 A US 3527318A US 845849 A US845849 A US 845849A US 3527318D A US3527318D A US 3527318DA US 3527318 A US3527318 A US 3527318A
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US
United States
Prior art keywords
nozzles
convergent
flaps
silencer
jet
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.)
Expired - Lifetime
Application number
US845849A
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English (en)
Inventor
Louis Duthion
Arsene Marzouvanlian
Andre E R Cabassut
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.)
Bertin Technologies SAS
Original Assignee
Bertin et Cie SA
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Filing date
Publication date
Application filed by Bertin et Cie SA filed Critical Bertin et Cie SA
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    • 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
    • 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
    • F02K1/38—Introducing air inside the jet
    • F02K1/386—Introducing air inside the jet mixing devices in the jet pipe, e.g. for mixing primary and secondary flow
    • 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
    • F02K1/40—Nozzles having means for dividing the jet into a plurality of partial jets or having an elongated cross-section outlet
    • 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

  • This invention relates to a jet-engine silencer, comprising essentially firstly a convergent element which is connected to the outlet pipe of the jet engine and branches into a plurality of parallel single convergent nozzles of elongate section through which the ejected gases issue in thin sheets mixing with secondary air drawn from the surroundings and, secondly, a ventilated divergent element which encloses the first element and whose upstream end is in the form of a frame provided with cores of elongate profile disposed at the exit of the respective convergent nozzles and forming single ventilated convergent-divergent nozzles.
  • This invention relates to a silencer, intended more particularly for jet engines, and, inter alia, supersonic aircraft power units, the outlet pipe of which has a substantially rectangular exit section.
  • the silencer according to the invention consists essentially of two basic elements, namely:
  • a convergent element An element having a convergent effect and hereinafter referred to as a convergent element, which is connected to the pipe and branches out into a plurality of parallel single convergent nozzles of elongate section, through which the gases ejected by the jet engine issue in thin sheets and mix with secondary air on the one hand and, if necessary, tertiary air on the other hand, such air being taken from the surroundings and admitted between the said nozzles.
  • the secondary air is drawn in upstream of the convergent element by the nozzle exit gases, while when the aircraft is crusing the secondary air having a pressure greater than atmospheric pressure at the flight altitude mixes of its own accord with the nozzle exit gases.
  • Tertiary air is admitted to the convergent element only if a negative pressure forms in the secondary air passage, and this effect occurs more particularly when the aircraft is at a low speed.
  • An element having a divergent effect and referred to as a ventilated divegent element which forms an extension of the first element and consists of a framework of streamlined cores forming a plurality of single ventilated convergent-divergent nozzles surrounding the exit end of each single convergent nozzle.
  • guide blades are provided between the single convergent nozzles and, if necessary, between the boundary nozzles and the fairing of the ventilated divergent element, so that the secondary air may be directed towards the outlet section of the gases ejected from the said nozzles.
  • the divergent element and more particularly the cores, are of sound-absorbent materials.
  • the nozzles of the convergent element have at their downstream exit, movable flaps whose orientation can be adjusted to give nozzle exit sections adapted to the different speeds of the aircraft, In their end position, the gas outlet of each convergent nozzle can be closed, while reverse flaps are simultaneously opened to direct the ejected gas jet in the oposite direction to the direction of travel of the aircraft (so that a braking or reverse effect can be obtained).
  • the flaps are disposed on the side walls of the single convergent nozzles and apertures are formed on the corresponding walls of the fairing of the divergent element.
  • the convergent element is symmetrical with respect to a central longitudinal plane of the silencer and at its inlet it divides into two parts each comprising the single convergent nozzles whose outlet sections are substantially perpendicular to the central plane.
  • the ventilated divergent element is symmetrical with respect to said plane and has a central core in said plane.
  • the single convergent nozzles may be bounded by flat walls, which are advantageously reinforced, and form a rectangular outlet section, but in order to reduce the weight of their structure while maintaining adequate strength they may alternatively be devised with orthogonally disposed corrugated walls.
  • Another construction which also provides good strength, is to form the nozzles by using a plurality of tubes which may or may not be juxtaposed, so that the outlet section is inscribed in a substantially rectangular form.
  • the movable flaps used to control the outlet section of the nozzles and the reverse flaps may be in appropriate forms, e.g., shields known per se in the form of half-shells.
  • FIG. 1 is a diagrammatic perspective of a silencer according to the invention.
  • FIG. 2 illustrates two half-sections on the lines IIaIIa and IIb-IIb in FIG. 3, of the same embodiment of the invention.
  • FIG. 3 is a diagrammatic section on the line III-III in FIG. 2.
  • FIG. 4 is a partial section on the line IV-IV in FIG. 2, to an enlarged scale.
  • FIGS. 5 to 7 are diagrammatic details showing how the gas ejection flaps used for reverse are mounted and controlled.
  • FIG. 8 is a diagrammatic partial view in the direction A in FIG. 1 showing one surface of the ventilated divergent element comprising tertiary air passage traps and reverse jet passages.
  • FIG. 9 is a partial diagrammatic section on the line IX-IX in FIG. 8.
  • FIG. 10 is a partial view showing a second embodiment of the outlet section of the single convergent nozzles.
  • FIG. 11 is a partial view of a variant of FIG. 10.
  • the silencer comprises two main elements, namely a convergent element comprising single convergent nozzles 1, the inlet of which is provided, for example, with a cylindrical collar 2 so that it can be connected to the pipe 3 of a jet engine, and a divergent element 4 of substantially parallelepipedal shape which encases the convergent element and the downstream end of which bears a frame formed from corrugated cores 31, a central core 15 and peripheral cores 30.
  • the convergent element divides into two symmetrical parts with respect to its central longitudinal plane P, each part comprising six single convergent elements 1 of elongate section in a plane substantially perpendicular to the plane P.
  • noozles one of which is shown in section in half of FIG. 2, while they are shown in side elevation in the other half, are progressively connected to the collar 2 and between them they form longitudinal passages 6 (FIG. 3), the downstream ends of which are formed by single ventilated convergent-divergent nozzles 32 bounded by the corrugated cores 31.
  • the passages 6 serve for the introduction of secondary air and the mixing thereof with the ejected gases takes place at the inlet of the single ventilated convergentdivergent nozzles 32 and undergoes expansion in the divergent element of said nozzles.
  • the passages 6 have guide blades 7 to promote the flow of secondary air.
  • Such blades may also be provided between the walls of the boundery nozzles and the side walls of the divergent element.
  • downstream sections of the single convergent nozzles may be closed by movable flaps 8 pivotally connected to pivots 9 perpendicular to the plane P.
  • flaps are controlled in pairs by jacks or actuators 10 pivotally connected to the divergent element 4 and linkages 11 so that they can be oriented either in parallel relationship to the pulsating jet as shown in half of FIG. 2, which is the normal operating position in which the aircraft is stationary, or be brought together into a closure position as shown by the other half of the figure, which is the reverse position, or intermediate positions corresponding to operation of the aircraft at different cruising speeds.
  • each linkage 11 is pivotally connected at one end of a rocker 12 which pivots about a stationary pivot 13 rigidly secured to a support 14 fixed to the central core 15 of the divergent element.
  • the other end of the rocker controls a rod 16 by means of a fork 42 which by means of the two pivots 41 is pivotally connected to the rocker 12 while it is pivotally connected to the rod 16 by the pivot 43 as shown in FIG. 4.
  • the rod 16 has pivots 17 to which links 18 are symmetrically pivotally connected and terminate in swivel joints 19 engaging in corresponding housings 20 with which the flaps 8 are provided.
  • the rods 16 are disposed in register with the secondary air passages so that when the said rods are moved in the direction of arrow F in FIG. 4- the flaps 8 are pushed towards the central plane of the nozzles so that the latter are closed.
  • Racks (FIG. 2) are secured, e.g. welded, to the end of the rods 16 and mesh with pinions 28 so that two rods or bars 16 disposed symmetrically with respect to the plane P are coupled.
  • the pinions 28 of each pair of rods or bars are also mounted, e.g. keyed on the same pinion shaft 29 in order to synchronise opening and closing of the reverse flaps and thus obviate any failure of one of the closure systems of the said flaps.
  • each of the nozzles 8 is open and provided with reverse flaps 21 whose elements are pivoted about transverse pivots 22 extending parallel to the central plane of the silencer. As shown in FIG. 5, these elements are so disposed that when they are folded down along the wall of the nozzle they close the latter without oifering any resistance to the gas flow.
  • cranks 23 may be open by an angle of about 60 in the forward direction by means of a linkage comprising cranks 23 keyed on pivots 22. These cranks, which are identical and parallel to one another are pivotally connected on a link 24 which allows them all to be moved together.
  • the link 24 has a side lug 25 (FIGS. 6 and 7) which engages in a S-shaped slot 26 in a plate 27 rigidly secured to the corresponding linkage 11. In this way the control of the reverse flaps is synchronised with the control of the flaps 8. However, when the lug 25 is in the straight part of the S, the flaps 8 can close a certain angle while the reverse flaps are still closed, and this is advantageous for controlling the outlet sections of the single convergent nozzles to adapt them to different flight conditions.
  • apertures 33 are formed in the wall of the divergent element 4 (FIGS. 8 and 9) to allow the gas jet to escape to the surroundings and produce the reversing effect.
  • Calibrated traps 34 are formed between each aperture 33 to admit tertiary air when a negative pressure occurs in the secondary air passage. The traps 34 open in the direction of the arrows shown in FIG. 9.
  • the divergent element 4 is closed by a thin casing of rectangular section. It comprises two walls 35 stiffened by U-cross-members. These walls are advantageously lined with sound-absorbent material, e.g. glass wool.
  • the peripheral cores forming the continuation of these walls are streamlined.
  • Corrugated cores 31 are provided in parallel relationship to the nozzles 1 and their upstream ends engage in the passages 6 separating the convergent nozzles.
  • the cores 31 enclose the supports 14 and the rods or bars 16 and the control system for the movable flaps 8. They are also lined with sound-absorbent material.
  • the corrugated cores 31 are stiffened by the central core 15 already mentioned in the description of the system for controlling the flaps 8.
  • the single convergent nozzles consist of flat walls 36 advantageously reinforced by ribs 37 forming a rectangular outlet section (FIG. 1).
  • the single convergent nozzles are formed by corrugated walls 38 forming a substantially rectangular section.
  • the single convergent nozzles are formed by a plurality of tubes 39 connected by walls 40, and the outlet section is inscribed in a substantially rectangular form.
  • a jet-engine silencer comprising essentially firstly a convergent element which is connected to the outlet pipe of the jet engine and branches into a plurality of parallel single convergent nozzles of elongate section through which the ejected gases issue in thin sheets mixing with secondary air drawn from the surroundings and, secondly, a ventilated divergent element which encloses the first element and whose upstream end is in the form of a frame provided with cores of elongate profile disposed at the exit of the respective convergent nozzles and forming single ventilated convergent-divergent nozzles.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Exhaust Silencers (AREA)
US845849A 1968-07-31 1969-07-29 Jet-engine silencer Expired - Lifetime US3527318A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR161354 1968-07-31

Publications (1)

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US3527318A true US3527318A (en) 1970-09-08

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US (1) US3527318A (enrdf_load_stackoverflow)
FR (1) FR1588852A (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3648800A (en) * 1970-04-27 1972-03-14 Gen Electric Coanda expansion exhaust nozzle suppressor
US3685612A (en) * 1970-05-04 1972-08-22 Bertin & Cie Boite Postale Gas ejection device with a silencer feature
US4287962A (en) * 1977-11-14 1981-09-08 Industrial Acoustics Company Packless silencer
JPH06159137A (ja) * 1992-08-03 1994-06-07 General Electric Co <Ge> 騒音レベルを低下させる排気システム、排気ノズルシステム、騒音レベルを低下させる方法、及び騒音抑制シュートアセンブリ

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2886946A (en) * 1955-04-14 1959-05-19 Canadair Ltd Thrust reversing device for turbojet engines
GB844179A (en) * 1957-10-16 1960-08-10 Rolls Royce Improvements in or relating to nozzles for jet propulsion purposes
CA609979A (en) * 1960-12-06 S. Schairer George Jet engine noise suppression
US3027713A (en) * 1958-01-31 1962-04-03 United Aircraft Corp Slotted jet engine noise suppressor
US3143184A (en) * 1960-10-31 1964-08-04 Bristol Siddeley Engines Ltd Nozzle for suppressing jet noise
US3333772A (en) * 1964-04-24 1967-08-01 Aviation Louis Breguet Sa Discharge nozzle apparatus for jet aircraft

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA609979A (en) * 1960-12-06 S. Schairer George Jet engine noise suppression
US2886946A (en) * 1955-04-14 1959-05-19 Canadair Ltd Thrust reversing device for turbojet engines
GB844179A (en) * 1957-10-16 1960-08-10 Rolls Royce Improvements in or relating to nozzles for jet propulsion purposes
US3027713A (en) * 1958-01-31 1962-04-03 United Aircraft Corp Slotted jet engine noise suppressor
US3143184A (en) * 1960-10-31 1964-08-04 Bristol Siddeley Engines Ltd Nozzle for suppressing jet noise
US3333772A (en) * 1964-04-24 1967-08-01 Aviation Louis Breguet Sa Discharge nozzle apparatus for jet aircraft

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3648800A (en) * 1970-04-27 1972-03-14 Gen Electric Coanda expansion exhaust nozzle suppressor
US3685612A (en) * 1970-05-04 1972-08-22 Bertin & Cie Boite Postale Gas ejection device with a silencer feature
US4287962A (en) * 1977-11-14 1981-09-08 Industrial Acoustics Company Packless silencer
JPH06159137A (ja) * 1992-08-03 1994-06-07 General Electric Co <Ge> 騒音レベルを低下させる排気システム、排気ノズルシステム、騒音レベルを低下させる方法、及び騒音抑制シュートアセンブリ

Also Published As

Publication number Publication date
FR1588852A (enrdf_load_stackoverflow) 1970-03-16

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