US2930195A - Oscillating flow combustion chamber - Google Patents

Oscillating flow combustion chamber Download PDF

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Publication number
US2930195A
US2930195A US565396A US56539656A US2930195A US 2930195 A US2930195 A US 2930195A US 565396 A US565396 A US 565396A US 56539656 A US56539656 A US 56539656A US 2930195 A US2930195 A US 2930195A
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Prior art keywords
liner
combustion chamber
lip
duct
combustion
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US565396A
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Jr Arthur W Blackman
Jr Arthur E Wetherbee
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Raytheon Technologies Corp
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United Aircraft Corp
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02KJET-PROPULSION PLANTS
    • F02K1/00Plants characterised by the form or arrangement of the jet pipe or nozzle; Jet pipes or nozzles peculiar thereto
    • F02K1/78Other construction of jet pipes
    • F02K1/82Jet pipe walls, e.g. liners
    • F02K1/822Heat insulating structures or liners, cooling arrangements, e.g. post combustion liners; Infra-red radiation suppressors
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T50/00Aeronautics or air transport
    • Y02T50/60Efficient propulsion technologies, e.g. for aircraft

Description

March 29, 1960 A. w. BLACKMAN, JR., ErAL 2,930,195
oscILLATmG FLow coMBusTroN CHAMBER Filed Feb. 14, 1956 FME .R MMF: N NKR m ECE T VAH NLT IEW@ v2p wE. y ww W HH T e A RT AR/ A Y fe B m E rif m y w f -LHM z l 4 M, my 4 w L e ||`w RITSQ l 2,930,195 1C@ Y Patented Malf- 29,1960*i osClLLATiNG uLow coMUsTroN CHAMBER Arthur W. Blackman, Jr., Manchester, and Arthur E.
- Wetherbee, Jr., Newington, Conn., assignors to United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Application February 14, 1956, Serial No. 565,396
Claims. (Cl. Gil-39.69)
This invention relates to combustion chambers and more particularly to combustion chambers having oscillating flow and combustion characteristics.
It is known that highly eflicient burning is att-ained in combustion chambers Whenthe phenomenon known as screech or oscillating liow occurs. However, with this burning characteristic the oscillations are normally uncontrollable to the extent that in an extremely short time they may become suiilciently violent to damage or destroy the particular combustion chamber. This burning characteristic occurs in afterburners of turbine type power plants, ramjets, or similar power plants where high temperatures and high burning rates are encountered. This type of combustion usually occurs in high output combustion chambers and is characterized by high amplitude oscillations occurring at a resonant frequency of the combustion chamber cavity. When this type of combustion is encountered the heat transfer rate to the cornbustion chamber wall is increased greatly. This increased heat transfer rate coupled with the high stress repetition rates of the pressure oscillations cause rapid failure of the combustion chamber structural components.
It is therefore an object of this invention to obtain the advantages of this type of combustion but to eliminate structural failures by controlling the. amplitude of the pressure oscillations.
It is a further object of this invention to increase the fluid mixing associated with oscillatory combustion and to increase the heat release rates in the process of the combustion reactions by providing a means for completing combustion in a much shorter combustion chamber length for a given efficiency level.
These and other objects of this invention will become readily apparent from the following detailedy description of the drawing in which:
Fig. 1 is a schematic sectional illustrationof a combustion chamber of rectangular cross section constructed according to this invention. A
Fig. 2 is a cross-sectional illustration taken along the line 2-2 of Fig. 1.
Fig. 3 is similar to Fig. 1 but illustrates a combustion chamber having a circular cross section, and
Fig. 4 is a cross-sectional illustration taken along the line 4--4 of Fig. 3.
Screeching combustion can be used practically if the amplitude of the pressure pulsations are controlled by properly locating the amefronts with respect to'the combustion chamber walls and by providing a properly designed 'absorption liner in the combustion chamber. Although the type of oscillatory combustion can be further controlled by regulating the fuel air limits, it is the provision of an absorptive liner of proper characteristics which can best provide highly eiilcient yet safe combustion.
It'is known that the pressure oscillations during screech or oscillatory combustion can be either acting along the of the ameholder.
axis of ow through the combustion chamber or transversely thereof. It has been found that the transverse oscillations produce more etiicient burning and can be produced and controlled in accordance with the teachings of this invention.
Referring to Fig. 1, a combustion chamber is generally indicated at 10 including a plurality of fuel nozzles 12. A V type ameholder 14 with suitable means of ignition 15 is provided with its downstream end. terminating n a lip 16 radially spaced outwardly from the axis of the combustion chamber. The ignition means 15 may be a pilot ame as shown or any other suitable form such as electrical or pyrotechnic ignition. `By properly locating the lip 16 from the axis of thecombustion chamber the preferred frequency of transverse oscillations during combustion can be obtained. lIn laddition an absorptive liner 20 is provided between the lip 16 and the outer wall 22 of the combustion chamber. The spacing of these components is related to other dimensions of the combustion chamber as described hereinafter. It should be noted that the perforations inthe liner 20 com prise radially extending unobstructed passagesto permit free radial flow of pressure tluctuations.
Fig. 1 illustrates a rectangular combustion chamber the relative shape and dimensions of Iwhich are more clearly shown in Fig. 2.
Fig. 3 illustrates a circular combustion chamber generally indicated at 30 as having fuel nozzles 32 and a conical flame-holder 34 which terminates in a down-l stream lip 36. The downstream lip 36 is spaced radially from the axis of the flow through the combustion chamber and this spacing is related to other dimensions of the combustion chamber as described hereinafter. An annular absorptive liner 40 is provided, and this liner is spaced inwardly from the outer combustion chamber casing 42 but is spaced radially outwardly from the lip 36 The particular configuration of the circular combustion chamber is better illustrated in Fig. 4.
The particular size and shape of the elements of this invention necessary to producethe proper oscillatory combustion with vthe best efficiency is set forth hereinafter.v Thus for example a transverse mode of oscillation can be excited more easily than a longitudinal mode of oscillation if the length to diameter ratio of the cornbustion chamber is less thanorequal to approximately 4 (see dimensions on Figs. l and 3). When the particular size of the combustion chamber for any particular requirement is determined, it is possible to then define the location of the flamefront (outer lip of the flameg holder) and the type of absorptive liner in terms of one or more dimensions of the combustion chamber.
According to this invention, then, it is best to excite the lowest frequency of a transverse mode of oscillation. This frequency may be expressed as:
D for cylindrical duct f=2cil for a rectangular duct where f=frequency C=speed of sound D=liner diameter h=longer side of rectangular duct frequency (f). Therefore it can be further shown that the liner qualities or design parameter tp is given as cr=percent open area of absorber L=air depth behind absorber facing I eff=eifective length of air column in liner perforations l eff:- [H- 1.770( 1-0.75a')] Y t=liner face thickness 'y=radius of each liner perforation -Hence once the diameter of the combustion chamber is' established (in the case of a cylindrical configuration) a. liner lwith the proper design properties can be selected.
Thus knowing that design parameter o is equal toi 13.55/D2, which in turn is identical with the variables shown above which comprise o, it is possible to design or choose the correct type of liner. The same holds true for `a rectangular combustion chamber.
It has been found that for etiicicnt operation the distance of the ilameholdcr lip from the longitudinal axis of the combustion chamber in the case of a cylindrical section is approximately equal to a value of 0.35 to 0.40 of the diameter ofthe absorptive liner. On the other hand the desirable distance of the ameholder lip from the longitudinal axis in the case o a rectangular section is approximately equal to or greater than a value of 0.35 to 0.40 of the dimension of the side of the rectangle formed by the duct.
It is readily apparent then that as `a result of this invention controlled oscillations can be produced in combustion chambers to reduce space requirements while at the same time avoiding destructive, high amplitude pressure oscillations.
The term combustion chamber so used herein is intended to include without limitation, reaction chambers where chemical reactions, decompositions or other similar process may occur since this invention is equally applicable thereto.
Although only two embodiments of this invention have been illustrated and described herein, it will become readily apparent that various changes and modications may be made in the construction and arrangement of the various parts without departing from the scope of this novel concept.
We claim:
1. In a combustion chamber, a cylindrical outer casing for defining a cylindrical burner duct, said duct having a longitudinal axis, a perforated cylindrical liner coaxially disposed in said duct, said liner with said duct forming a tuned chamber open at both ends, the perforations of said liner comprising radially extending unobstructed passages, a conical arneholder in said duct and having an outer lip located adjacent said liner, said lip being spaced from said axis a distance which is greater than 0.35 to 0.40 of the diameter of said liner, and means for intro ducing fuel upstream of said liameholder.
2. In a combustion chamber, a cylindrical outer casing for defining a cylindrical burner duct, said duct having a longitudinal axis, a perforated cylindrical liner coaxially disposed in said duct, said liner with said duct forming an annular chamber open at both ends for free iow through said chamber, the perforations in said liner comprising radially extending unobstructed passages, a conical fiameholder in said duct and having an outer lip located adjacent said liner, said lip being spaced from said axis a distance which is greater .than 0.35 to 0.40 of the diameter of said liner, the distance from said lip Vto the downstream end of said combustion chamber being approximately equal-to. a distance less lthan four times the diameter of said liner, and means for introducing fuel upstream of said ameholder.
3. In a combustion chamber, a tubular outer casing for dening a cylindrical burner duct, said duct having a longitudinal axis, a perforated cylindrical liner coaxially disposed in said duct, said liner with said duct forming an annular tuned chamber open at both ends along said axis, the perforations in said liner comprising unobstructed passages running normal to said axis, a flameholder in said duct having a V cross section and having its downstream end terminating in an outer lip radially displaced from said axis and adjacent said liner, said lip being spaced from said axis approximately equal to a distance which is of a value approximately in the range of 0.35 to 0.40 of the diameter of said liner.
4. A combustion chamber having a casing for delining a burner duct, said duct having a longitudinal axis, means for injecting fuel at an upstream station in said duct, imperforate tlameholder means in said duct downstream of said fuel injecting means, and terminating in at least one outer lip from which a ilamefront emanates in a downstream direction, said lip being located a distance away from said axis, and an absorptive liner coaxially disposed with respect to said casing and being radially located between said lip and said casing thereby forming a space therebetween, said liner being cylindrical and perforated substantially throughout its length, said perforations comprising unobstructed radial passages extending substantially normal to said axis, the upstream end of` said liner being located adjacent said lip and extending downstream thereof whereby said liner lies substantially in the amefront and whereby said space forms a tuned chamber open at its axial ends.
5. A combustion chamber having a casing for deiining la burner duct, said duct having a longitudinal axis, means for injecting fuel at an upstream station in said duct, imperforate flameholder means in said duct downstream of said fuel injecting means, and terminating in at least one outer lip from which a amefront emanates in a downstream direction, said lip being located a distance away from said axis, and an absorptive liner coaxially disposed with respect to said casing and being radially located between said lip and said casing thereby forming a space therebetween, said liner being cylindrical and perforated substantially throughout its length, said perforations comprising unobstructed radial passages extending substantially normal to said axis, the upstream end of said liner being located adjacent said lip and extending downstream thereof whereby said liner lies substantially in the amefront and whereby said space forms a tuned chamber open at its axial ends, said lip being spaced from said axis a distance which is .035 to .045 of the maximum cross-sectional dimension of said liner, the distance from said lip to the downstream end ofsaid combustion chamber being -approximately equal to a distance less than four times the said maximum cross-sectional dimension of said liner.
References Cited in the file of this patent UNITED STATES PATENTS 2,517,015 Mock et al. Aug. l, 1950 2,602,292 Buckland et al. July .8, 1952 2,658,339 Bonsall Nov. 10, 1953 2,705,401 Allen et al. Apr. 5, 1955 2,778,192 Kroon Ian. 22, 1957 2,874,536 Benson et al Feb. 24, 1959 FOREIGN PATENTS 202,851 Australia July 27, 1956 (Duplicate of U.S. Patent 2,874,536, Feb. 24, 1959) 525,083 Belgium Dec. 31, 1953
US565396A 1956-02-14 1956-02-14 Oscillating flow combustion chamber Expired - Lifetime US2930195A (en)

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3685611A (en) * 1971-03-24 1972-08-22 Rohr Corp Duct with lining of spaced bands for suppressing sound in a gas steam transmitted therethrough
US3848697A (en) * 1972-07-04 1974-11-19 Aerospatiale Acoustic damping and cooling of turbojet exhaust ducts
US3921391A (en) * 1972-04-13 1975-11-25 Us Navy Combustor wing vortex generators
US5417056A (en) * 1992-01-02 1995-05-23 General Electric Company Axially translating screen suppressor for a gas turbine engine augmentor
US6164058A (en) * 1997-07-15 2000-12-26 Abb Research Ltd. Arrangement for damping combustion-chamber oscillations
US20030115879A1 (en) * 2001-12-21 2003-06-26 Mitsubishi Heavy Industries Ltd. Gas turbine combustor
US20080118343A1 (en) * 2006-11-16 2008-05-22 Rolls-Royce Plc Combustion control for a gas turbine
US9677766B2 (en) * 2012-11-28 2017-06-13 General Electric Company Fuel nozzle for use in a turbine engine and method of assembly

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE525083A (en) * 1952-12-20
US2517015A (en) * 1945-05-16 1950-08-01 Bendix Aviat Corp Combustion chamber with shielded fuel nozzle
US2602292A (en) * 1951-03-31 1952-07-08 Gen Electric Fuel-air mixing device
US2658339A (en) * 1950-11-29 1953-11-10 Lucas Ltd Joseph Sheet metal combustion chamber, flame tube, and the like
US2705401A (en) * 1950-12-02 1955-04-05 Armstrong Siddeley Motors Ltd Vaporising means for liquid fuel combustion chambers
US2778192A (en) * 1953-10-22 1957-01-22 Westinghouse Electric Corp Combustor basket structure
US2874536A (en) * 1954-03-18 1959-02-24 Gen Electric Cooling means for tailpipe

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2517015A (en) * 1945-05-16 1950-08-01 Bendix Aviat Corp Combustion chamber with shielded fuel nozzle
US2658339A (en) * 1950-11-29 1953-11-10 Lucas Ltd Joseph Sheet metal combustion chamber, flame tube, and the like
US2705401A (en) * 1950-12-02 1955-04-05 Armstrong Siddeley Motors Ltd Vaporising means for liquid fuel combustion chambers
US2602292A (en) * 1951-03-31 1952-07-08 Gen Electric Fuel-air mixing device
BE525083A (en) * 1952-12-20
US2778192A (en) * 1953-10-22 1957-01-22 Westinghouse Electric Corp Combustor basket structure
US2874536A (en) * 1954-03-18 1959-02-24 Gen Electric Cooling means for tailpipe

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3685611A (en) * 1971-03-24 1972-08-22 Rohr Corp Duct with lining of spaced bands for suppressing sound in a gas steam transmitted therethrough
US3921391A (en) * 1972-04-13 1975-11-25 Us Navy Combustor wing vortex generators
US3848697A (en) * 1972-07-04 1974-11-19 Aerospatiale Acoustic damping and cooling of turbojet exhaust ducts
US5417056A (en) * 1992-01-02 1995-05-23 General Electric Company Axially translating screen suppressor for a gas turbine engine augmentor
US6164058A (en) * 1997-07-15 2000-12-26 Abb Research Ltd. Arrangement for damping combustion-chamber oscillations
US20030115879A1 (en) * 2001-12-21 2003-06-26 Mitsubishi Heavy Industries Ltd. Gas turbine combustor
US7013647B2 (en) * 2001-12-21 2006-03-21 Mitsubishi Heavy Industries, Ltd. Outer casing covering gas turbine combustor
US20080118343A1 (en) * 2006-11-16 2008-05-22 Rolls-Royce Plc Combustion control for a gas turbine
US9677766B2 (en) * 2012-11-28 2017-06-13 General Electric Company Fuel nozzle for use in a turbine engine and method of assembly

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