US3095696A - Combustion-engine exhaust systems - Google Patents

Combustion-engine exhaust systems Download PDF

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Publication number
US3095696A
US3095696A US57003A US5700360A US3095696A US 3095696 A US3095696 A US 3095696A US 57003 A US57003 A US 57003A US 5700360 A US5700360 A US 5700360A US 3095696 A US3095696 A US 3095696A
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Prior art keywords
nozzle
jacket
stream
engine
space
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US57003A
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English (en)
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Roy W Rumble
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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
    • F02K1/78—Other construction of jet pipes
    • F02K1/82—Jet pipe walls, e.g. liners
    • F02K1/827—Sound absorbing structures or liners

Definitions

  • the object of this invention is to propose a method of reducing the noise made by combustion engines and especially by the streams of exhausting gases.
  • Sound can only be freely propagated in a gaseous '1'I16d1- um, and the basisupon which the invention proceeds is to form and maintain, around the engine and in particular in the zone of the emergent stream, a condition of reduced pressure which attenuates the sound produced by the stream.
  • the zone of reduced pressure may be produced by the stream itself, for instance by shaping the conduit through which the stream emerges to induce into the stream flow of air from the annular zone surrounding it.
  • the'zone. is created by' mechanical means such as a fan driven by the prime mover or by the emergent stream, or both.
  • the exhaust stream be broken up into separate parallel streams in a closed pattern with zones of reduced pressure occluded in the streams.
  • the whole stream is still provided with a zone of reduced pressure around its periphery.
  • FIGURE 1 is a longitudinal section through the tail end of a jet engine
  • FIGURE 2 is a longitudinal section of a second arrangement
  • FIGURE 3 is a cross-section on the line 3--3 of FIG- URE 2;
  • FIGURE 4 is a longitudinal section through a jet engine
  • FIGURE 5 is a side view of one form of nozzle and difluser pipe
  • FIGURE 6 is a section on the line 66 of FIGURE 5;
  • FIGURE 7 is a side view in section of another embodiment.
  • FIGURE 1 there is seen the nozzle 10 of a jetpropulsion engine with the jet stream 12 emerging from the annular duct 14 defined between the nozzle and the hub fairing 16.
  • the jet stream In the immediate vicinity of the nozzle 10, the jet stream, as it leaves the nozzle, is indicated'by chain-dotted lines. In that vicinity the stream behaves virtually like a solid body, that is to say there is no significant diffusion or dissociation at its periphery into the ambient atmosphere.
  • the nozzle and the emergent stream are surrounded by a jacket 18 that defines between itself and the stream a space 20 that is annular or of other cross-section depending upon the shape ofthe nozzle.
  • the jacket has an inward flange 22 that terminates just outside the periphery of the stream 12, so that the space 20 is substantially enclosed.
  • the jacket is connected to a source of suction by pipes 24.
  • the space 20 is maintained at a pressure reduced below atmospheric pressure by continuously applying suction to it.
  • the sound of the emergent stream is attenuated as it traverses the space 20.
  • the noise of the engine is thereby sensibly diminished.
  • FIGURE 4 A means of applying suction to the space 20 is shown in FIGURE 4.
  • a fan 26 is located at the nozzle 28 to be impinged on by the gas stream and rotated.
  • the fan blades 30 are extended beyond the.
  • the blades in the space are of reversed pitch so that they apply suction to the space Y 32 that surrounds the emergent stream.
  • the fan 26 may be driven by the turbine through a shaft33.
  • the space 32 communicates with the intake 34 to the turbine 36. Air in going to the turbine tends to induce the flow of gas along the space 32 and into the air-stream, so that the entire space 32 is at reduced pressure. Noise evolved by the engine as well as the jet stream is thereby attenuated.
  • one stage 38 of the turbine can be extended into the space 32, as shown at 40, where the pitch of the blade tips is reversed.
  • FIGURES 2 and 3 an arrangement as shown in FIG- URE 1, or it may be in FIGURE .4, is used, butwithin the nozzle 42 there is arranged a pattern of vanes-'44 spaced apart to splitthe jet stream into a number of separate channels. ,Between the channels the pressure is reduced. Each channel is thus surrounded by a zone of reduced pressure, and the whole stream is surroundedby a zone of reduced pressure within the space 46.
  • FIGURESS and 6 there is seen a baffle structuredefining a pattern of vanes 48' of another kind.
  • the area of the nozzle 50* contains an arrangement consisting in a series of pyramidal pockets 52 open 'at their mouths 54 which are directed rearwardly. These pockets occur right round the periphery of the nozzle and also within the 1 nozzle itself.
  • the various pockets 52 define between them a series of spaces 56 through which the jet stream SSemerges.
  • nozzle and tube may be surrounded by a jacket, as shown in FIGURES 1 to 4, or not.
  • the nozzle is, of course, dimensioned for the aggregate area of the openspaces 56 to be adequate to pass the jet stream.
  • the effect of the pockets 53 is that the stream flowing through the spaces 56 (which act as venturis) into the difiuser tube 58 tends to induce flow of air from the pockets 52 into the stream. As these pockets are closed, they are maintained at a reduced pressure which acts to attenuate the noise produced by the jet stream.
  • FIGURE 7 it is the jet stream 62 itself that acts to reduce the pressure within the jacket 64.
  • the stream passing through the venturi constituted by the convergent nozzle 65 and the divergentdifiuser tube 66 induces flow
  • the throat of the nozzle 65 may contain a pattern of vanes 70 comprising pyramidal pockets 72 and rearwardly directed aerofoils 74 within the mouths of the pockets.
  • the stream 62 tends to induce flow of air from the pockets and aerofoils, which are maintained under reduced pressure.
  • some reverse flow of the exhaust gases may take place into the enclosed space around the exhaust stream, but the momentum of the stream prevents any reverse flow of significant proportion, and what reverse flow there is does not materially aifect the condition of reduced pressure within the space.
  • the nozzle may be circular in section and the jacket likewise; but preferably the jacket and desirably also the nozzle are polygonal, so that sound waves tend to be reflected from the wall of the jacket, or both of them, back into the stream.
  • a jet propulsion engine including a conduit for the jet stream and comprising a convergent nozzle having an inlet mouth disposed at the discharge end of said conduit, a jacket coaxially disposed at and surrounding said nozzle and having a portion extending downstream of said nozzle, said portion having inwardly directed flanges which define an aperture having substantially the same diameter as said convergent nozzle exit mouth, and means being provided in said jacket to reduce the pressure in the space forbed between said convergent nozzle and said jacket to reduce the noise level.
  • said means consists of a rotor having turbine blades of a predeterminedpitch mounted in the exit mouth of said convergent nozzle-and being rotated by the fluid flow, said blades having extensions forming fan blades having a different pitchthan said predetermined pitch and being disposed in thespace formed between said convergent nozzle and said jacket, whereby the fan moves gases forwardly with respect to the nozzle.
  • said means consists of a divergent diffuser tube connected to the mouth' of said convergent nozzle, and said jacket contains pipe means connected to a source of suction.
  • said means consists of a divergent diffuser tube disposed within said jacket, one end of said divergent diffuser tube surrounding said convergent nozzle in overlapping relationship but providing an opening therebetween, the other end of said divergent diffuser tube being of greater diameter than said one end thereof and providing another opening between the'other end of said divergent diffuser tube and said jacket, vanes being disposed in the exit mouth of said 7.
  • a jet propulsion engine comprising a convergent nozzle disposed-atthe discharge end of said engine for discharging the exhaust thereof, a divergent difiuser tube having one end the same diameter as said convergent nozzle exit and being mounted thereon,'said divergent diffuser tube extending in progressively-increasing diameter to the other'en'd thereof, ajacket having one end surrounding said convergent nozzle and the one end of said divergent diffuser tube and containing a portion extending downstream and beyond the other end of said divergent difiuser tube and means to reduce the pressure within the space between said divergent difiuser tube and said jacket, said-portion having inwardly directed flanges to define an aperture having substantially-the same diameter as said convergent nozzle exit, and a baffle structure disposed in said convergent nozzle to divide the exhaust 4 into a number of separate channels to reduce the noise level of the engine.
  • a jet propulsion engine in which said jacket is connected to a source of suction.
  • a jet propulsion engine in which the one end of said divergent diffuser tube has an overlapping portion which overlaps said convergent nozzle in spaced relationship to define an opening therebetween, the other end of said divergent diffuser tube terminating in spaced relationship with respect to said jacket to define a further opening therebetween.
  • bafiie'structure consists of a number of closed pyramidal pockets provided with rearwardly directed and spaced apart mouths.
  • a jet propulsion engine according to claim 10* in which rearwardly directed aerofoils' are disposed within the rearwardly directed and spaced apart months.
  • a jet propulsion engine in which said baffle structure consists of a number of rearwardly directed aerofoil vanes.
  • a jet propulsion engine comprising a turbine mounted therein, an intake disposed in the rfront part of said engine and communicating with said turbine to lead a fluid thereto, a convergent nozzle disposed in the back part of said engine and communicating with said turbine for discharging the exhaust fluid therefrom, a jacket surrounding substantially the entire length of said engine and spaced therefrom to define a space of reduced pres sure, said jacket having a portion extending beyond said convergent nozzle, said portion of said jacket terminating into inwardly directed flanges defining an aperture having substantially the same diameter as said convergent nozzle,
  • a jet propulsion engine comprising a turbine mounted therein, an intake disposed in the front part of said engine and communicating with said turbine to lead a fluid thereto, a convergent nozzle disposed in the'back part of said engine and communicating with said turbine lfOl discharging the exhaust fluid therefrom, a jacket surrounding substantially the entire length of said engine and spaced therefrom to define a space of reduced pres sure said jacket having a portion extending beyond said convergent nozzle, said portion of said jacket terminating into inwardly directed flanges defining an aperture having substantially the same diameter as said convergent nozzle, and a fan disposed at the discharge end of said convergent nozzle having turbine blades of a predetermined pitch located within the path of the exhaust discharging from said convergent nozzle, said turbine bladescontaining extensions having another pitch different from said predetermined pitch disposed in the space of reduced pressure between said jacket and said convergent nozzle to reduce the noise level of the engine; the turbine having a further fan mounted there

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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)
US57003A 1959-09-25 1960-09-19 Combustion-engine exhaust systems Expired - Lifetime US3095696A (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
ZA3095696X 1959-09-25
ZA593792 1960-03-25
ZA602491 1960-06-17
ZA604429 1960-10-31

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BE (1) BE601814A (fr)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3371743A (en) * 1965-04-29 1968-03-05 American Radiator & Standard Jet exhaust silencing nozzle with suction applied at exit wall
US3410093A (en) * 1967-05-26 1968-11-12 Ghougasian John Nazareth Reaction thrust engine with fluid operated compressor
US3548597A (en) * 1968-09-16 1970-12-22 Alexander Hossen Etessam Turbine engine for aircraft having a supplementary compressor driven by a supplementary turbine
US3575260A (en) * 1969-05-15 1971-04-20 Rohr Corp Method and apparatus for augmenting the thrust of a jet-propelled aircraft and suppressing the noise thereof
US4843814A (en) * 1985-12-02 1989-07-04 Von Ingelheim Peter G Assembly for producing a propulsive force
US6094907A (en) * 1996-06-05 2000-08-01 The Boeing Company Jet engine and method for reducing jet engine noise by reducing nacelle boundary layer thickness
US20090077946A1 (en) * 2007-03-30 2009-03-26 Masatsugu Ishiba Fan control apparatus
US20100293920A1 (en) * 2009-05-20 2010-11-25 Rolls-Royce Plc Propfan engine
US8192141B1 (en) * 2007-04-05 2012-06-05 The United States Of America As Represented By The Secretary Of The Air Force Dual compression rotor
US20130216371A1 (en) * 2012-02-22 2013-08-22 Honeywell International Inc. Turboprop engine systems with noise reducing inlet assemblies
US10260417B2 (en) * 2015-12-22 2019-04-16 General Electric Company Air intake turboprop assemblies

Citations (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2168528A (en) * 1934-11-08 1939-08-08 Kadenacy Michel Exhaust passage of two-stroke internal combustion engines
GB654344A (en) * 1954-11-25 1951-06-13 Cie Electro Mecanique 12 Method of regulating gas turbine jet-propulsion plants, and means therefor
US2575735A (en) * 1945-05-14 1951-11-20 Const Aeronautiques Du Sud Que Means for adjusting the effective exit cross-section of a nozzle or the like
US2620624A (en) * 1952-12-09 wislicenus
US2637166A (en) * 1948-10-07 1953-05-05 James M Carswell Pure reaction turbine with evacuated chamber and rotor element therefor
US2674087A (en) * 1948-05-13 1954-04-06 Peters & Russell Inc Exhaust deflector
FR1114647A (fr) * 1954-11-19 1956-04-16 Snecma Refroidissement des organes et accessoires d'avions exposés à des températures élevées
US2800765A (en) * 1947-08-27 1957-07-30 Westinghouse Electric Corp Movable flame holder for combustion apparatus
GB783003A (en) * 1955-03-31 1957-09-18 Power Jets Res & Dev Ltd Apparatus for reducing the noise of a fluid stream
US2882679A (en) * 1950-12-22 1959-04-21 Gen Motors Corp Augmenter type afterburner for jet propelled aircraft
US2892582A (en) * 1956-08-17 1959-06-30 O'rourke Neil Simplified boundary layer control for a jet
US2915136A (en) * 1956-05-28 1959-12-01 Friedrich O Ringleb Apparatus for suppressing noise
FR1199576A (fr) * 1957-03-06 1959-12-15 Power Jets Res & Dev Ltd Perfectionnements apportés aux installations motrices avec turbine à gaz, notamment pour la propulsion par réaction
US2920445A (en) * 1957-01-15 1960-01-12 Curtiss Wright Corp Flame holder apparatus
FR1208542A (fr) * 1958-06-19 1960-02-24 & De Construction De Moteurs D Perfectionnements aux dispositifs de réglage des jets
US2974744A (en) * 1961-03-14 Silencer
US3009318A (en) * 1960-04-22 1961-11-21 Ryan Aeronautical Co Turbofan engine with reversible pitch fan

Patent Citations (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2974744A (en) * 1961-03-14 Silencer
US2620624A (en) * 1952-12-09 wislicenus
US2168528A (en) * 1934-11-08 1939-08-08 Kadenacy Michel Exhaust passage of two-stroke internal combustion engines
US2575735A (en) * 1945-05-14 1951-11-20 Const Aeronautiques Du Sud Que Means for adjusting the effective exit cross-section of a nozzle or the like
US2800765A (en) * 1947-08-27 1957-07-30 Westinghouse Electric Corp Movable flame holder for combustion apparatus
US2674087A (en) * 1948-05-13 1954-04-06 Peters & Russell Inc Exhaust deflector
US2637166A (en) * 1948-10-07 1953-05-05 James M Carswell Pure reaction turbine with evacuated chamber and rotor element therefor
US2882679A (en) * 1950-12-22 1959-04-21 Gen Motors Corp Augmenter type afterburner for jet propelled aircraft
FR1114647A (fr) * 1954-11-19 1956-04-16 Snecma Refroidissement des organes et accessoires d'avions exposés à des températures élevées
GB654344A (en) * 1954-11-25 1951-06-13 Cie Electro Mecanique 12 Method of regulating gas turbine jet-propulsion plants, and means therefor
GB783003A (en) * 1955-03-31 1957-09-18 Power Jets Res & Dev Ltd Apparatus for reducing the noise of a fluid stream
US2915136A (en) * 1956-05-28 1959-12-01 Friedrich O Ringleb Apparatus for suppressing noise
US2892582A (en) * 1956-08-17 1959-06-30 O'rourke Neil Simplified boundary layer control for a jet
US2920445A (en) * 1957-01-15 1960-01-12 Curtiss Wright Corp Flame holder apparatus
FR1199576A (fr) * 1957-03-06 1959-12-15 Power Jets Res & Dev Ltd Perfectionnements apportés aux installations motrices avec turbine à gaz, notamment pour la propulsion par réaction
FR1208542A (fr) * 1958-06-19 1960-02-24 & De Construction De Moteurs D Perfectionnements aux dispositifs de réglage des jets
US3009318A (en) * 1960-04-22 1961-11-21 Ryan Aeronautical Co Turbofan engine with reversible pitch fan

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3371743A (en) * 1965-04-29 1968-03-05 American Radiator & Standard Jet exhaust silencing nozzle with suction applied at exit wall
US3410093A (en) * 1967-05-26 1968-11-12 Ghougasian John Nazareth Reaction thrust engine with fluid operated compressor
US3548597A (en) * 1968-09-16 1970-12-22 Alexander Hossen Etessam Turbine engine for aircraft having a supplementary compressor driven by a supplementary turbine
US3575260A (en) * 1969-05-15 1971-04-20 Rohr Corp Method and apparatus for augmenting the thrust of a jet-propelled aircraft and suppressing the noise thereof
US4843814A (en) * 1985-12-02 1989-07-04 Von Ingelheim Peter G Assembly for producing a propulsive force
US6094907A (en) * 1996-06-05 2000-08-01 The Boeing Company Jet engine and method for reducing jet engine noise by reducing nacelle boundary layer thickness
US20090077946A1 (en) * 2007-03-30 2009-03-26 Masatsugu Ishiba Fan control apparatus
US8590288B2 (en) * 2007-03-30 2013-11-26 Toyota Jidosha Kabushiki Kaisha Fan control apparatus
US8192141B1 (en) * 2007-04-05 2012-06-05 The United States Of America As Represented By The Secretary Of The Air Force Dual compression rotor
US8356469B1 (en) 2007-04-05 2013-01-22 The United States Of America As Represented By The Secretary Of The Air Force Gas turbine engine with dual compression rotor
US20100293920A1 (en) * 2009-05-20 2010-11-25 Rolls-Royce Plc Propfan engine
US8689558B2 (en) * 2009-05-20 2014-04-08 Rolls-Royce Plc Propfan engine
US20130216371A1 (en) * 2012-02-22 2013-08-22 Honeywell International Inc. Turboprop engine systems with noise reducing inlet assemblies
US9057329B2 (en) * 2012-02-22 2015-06-16 Honeywell International Inc. Turboprop engine systems with noise reducing inlet assemblies
US10260417B2 (en) * 2015-12-22 2019-04-16 General Electric Company Air intake turboprop assemblies

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Publication number Publication date
BE601814A (fr) 1961-07-17

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