Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23R—GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGH VELOCITY, e.g. GAS-TURBINE COMBUSTION CHAMBERS
  • F23R3/00—Continuous combustion chambers using liquid or gaseous fuel
  • F23R3/02—Continuous combustion chambers using liquid or gaseous fuel characterised by the air-flow or gas-flow configuration
  • F23R3/16—Continuous combustion chambers using liquid or gaseous fuel characterised by the air-flow or gas-flow configuration with devices inside the flame tube or the combustion chamber to influence the air or gas flow
  • F23R3/18—Flame stabilising means, e.g. flame holders for after-burners of jet-propulsion plants
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02K—JET-PROPULSION PLANTS
  • F02K3/00—Plants including a gas turbine driving a compressor or a ducted fan
  • F02K3/08—Plants including a gas turbine driving a compressor or a ducted fan with supplementary heating of the working fluid; Control thereof
  • F02K3/105—Heating the by-pass flow
  • F02K3/11—Heating the by-pass flow by means of burners or combustion chambers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02K—JET-PROPULSION PLANTS
  • F02K7/00—Plants in which the working fluid is used in a jet only, i.e. the plants not having a turbine or other engine driving a compressor or a ducted fan; Control thereof
  • F02K7/10—Plants in which the working fluid is used in a jet only, i.e. the plants not having a turbine or other engine driving a compressor or a ducted fan; Control thereof characterised by having ram-action compression, i.e. aero-thermo-dynamic-ducts or ram-jet engines
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2220/00—Application
  • F05D2220/10—Application in ram-jet engines or ram-jet driven vehicles
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2300/00—Materials; Properties thereof
  • F05D2300/20—Oxide or non-oxide ceramics
  • F05D2300/21—Oxide ceramics
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2300/00—Materials; Properties thereof
  • F05D2300/20—Oxide or non-oxide ceramics
  • F05D2300/21—Oxide ceramics
  • F05D2300/2112—Aluminium oxides
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2300/00—Materials; Properties thereof
  • F05D2300/20—Oxide or non-oxide ceramics
  • F05D2300/22—Non-oxide ceramics
  • F05D2300/226—Carbides
  • F05D2300/2261—Carbides of silicon
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2300/00—Materials; Properties thereof
  • F05D2300/20—Oxide or non-oxide ceramics
  • F05D2300/22—Non-oxide ceramics
  • F05D2300/228—Nitrides
  • F05D2300/2283—Nitrides of silicon
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2300/00—Materials; Properties thereof
  • F05D2300/60—Properties or characteristics given to material by treatment or manufacturing
  • F05D2300/614—Fibres or filaments
• • 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 refers to a flameholder device, particularly for ram-jet engines and after-burners in turbo ⁇ jet engines and comprising an annular body coaxial with the centre axis of the engine and being in the shape of a plura ⁇ lity of circumferentially spaced thin-walled metal guide vanes, upstream of which fuel nozzles are mounted and down ⁇ stream of which a turbulent combustion-stabilizing zone is formed, said guide vanes being hollow and having relatively great volume, and said guide vanes, if desired, being cooled by means of air flowing therethrough, said guide vanes fur ⁇ thermore being protected by a ceramic material.
• the function of flameholders is to create turbulence and wakes in the flow particularly in after-burners of jet engines but also in other kinds of engines such as ram-jet engines for space propulsion.
• the turbulent zone the mix ⁇ ture of fuel and air has time to be lit before it flows out of the engine. In this way the combustion is kept within the engine and provides an additional thrust.
• a flameholder device is subjected to high gas flows, high temperatures and rapid temperature changes. The heat radiation from the flame directly downstream provides very high surface temperatures. From the core engine gases leave the turbine exit which have a temperature of about 900°C.
• cold fuel is supplied through fuel nozzles directly upstream the flamehol ⁇ der which leads to thermo-chock effects.
• Today flame-holders are made of metal material having a thermally isolating surface layer of Zr0 2 .
• the flame holder might be made from annular bodies having V-formed crossectional shape or guide vanes which guide the flow into a spiral motion. As far as guide vanes are concerned, they often have a great internal volume which may be closed or passed by a flow of cooling turbine outlet gases. Should cracks occur at the front edge of the guide vane due to thermo-chock from the cooling liquid fuel, the fuel-air mixture can flow into the guide vane and start to burn within the internal volume thereof. This leads to a fast destructive burning of said guide vane such that the flame- holding function no longer might be assured.
• the ceramic material is made as a closed box-like insert body within the cavity of the guide vanes, which insert body with its outer surface lies close to the internal surface of the guide vane walls at all places and being hollow itself or, in case of cooling by an air flow, having opening corresponding to the through-flow openings in the guide vane walls, or is filled with a porous ceramic material or entirely consists of such porous material.
• the invention can now be effec- tively prevented that in case of cracks occuring in the walls of the metal guide vanes this can lead to the intrusion and combustion of fuel-air mixture at the inside of said walls.
• Fig. 1 is a side elevational view, partly in cross section, of a jet engine with an inventive after-burner flame holder device
• Fig. 2 illustrates in an enlarged view a portion of the sectioned part of the very flame-holder of the engine of Fig. 1
• Fig. 3 illustrates in section and in an end view inventive guide vanes
• Fig. 4 is a perspective view of a flameholder device comprising guide vanes of Fig. 3 accor ⁇ ding to the invention
• Fig. 5 illustrates various possible combinations of metal and ceramic materials according to the invention
• Fig. 6 and 7 is a longitudinal and, a cross- sectional view, respectively, of an air-cooled embodiment of « an inventive guide vane.
• Fig. 1 is illustrated a turbojet engine in a partly sectioned side elevational view to show the after- burner portion located therein.
• an annular flameholder 2 with V-shaped cross section.
• a pilot nozzle 1 which belongs to the after-burner portion and in the annular body of the flameholder are mounted a number of circumferentially dis ⁇ tributed thin-walled metal guide vanes 4.
• a closed box-like insert body 3 of fibre-reinfor ⁇ ced ceramic material. With its external surface said body follows essentially the contour of the limiting walls of the internal cavity and can itself be hollow.
• the flameholder comprises a number of circumferentially distribu ⁇ ted guid vanes 4.
• said guide vanes have an enlarged airfoil ⁇ like shape and therefore their internal volume becomes great and according to the invention said volume thus houses a fibre-reinforced ceramic body 3 with a peripheral contour which at all places lies close to the inner surface of the guide vane walls.
• the above-stated fibre-reinforced ceramic bodies now provide for an essentially reduced risk for destructive burning of the flameholder portions and allow the use of an already known and existing flameholder structure of sheet metal.
• the fibre-reinforced ceramic body is entirely embedded into the metal construction and does not need to serve as load-carrying structural element. Therefore, the device according to the invention is very reliable.
• Ceramic materials which are possible to use in this connection are firstly ceramic composites with continuous fibres of SiC, Si 3 N 4 , A1 2 0 3 or mullite (or other carbides, nitrides, oxides or borides) in a ceramic matrix of the same group of materials.
• ceramic composi ⁇ tes it is to be mentioned SiC f /Si 3 N 4 , SiC f /Al 2 0 3 and SiC f / SiC, where the index f means fibre.
• monolitic ceramics, i.e. without fibre reinforcing may be used.
• An example thereof has been illustrated in Fig. 5a which shows a ceramic insert 3 for a flameholder guide vane 4.
• a porous vacuum-formed fibre-reinforced body 3 typically having about 80% porosity, entirely fills the internal volume as illustrated in Fig. 2.
• Said fibre body 3 may consist of e.g. fibres of A1 2 0 3 , Si0 2 , mullite, Zr0 2 or aluminium silicate glass (or another oxide, carbide, nitride or boride) of loose-wool type, which is vacuum-formed with an inorganic binder which may be a Si0 2 -sol.
• This type of mate- rial is previously known in connection with the use as ther ⁇ mal isolation in ovens and in space vessels.
• the form stability of ceramic mate ⁇ rials at high temperatures is utilized without having to rely upon said ceramic material as a load-carrying component in normal conditions of operation.
• Figs. 6 and 7 has been illustrated an embodiment of the guide vanes 4 which is cooled by hot air flowing therethrough.
• the insert body 3 is hollow and provided with suitable inlet and outlet openings for said airflow in accordance with the corresponding openings in the surrounding guide vane walls at an upstream inlet ladle 9 and a downstream flame zone 10.
• suitable inlet and outlet openings for said airflow in accordance with the corresponding openings in the surrounding guide vane walls at an upstream inlet ladle 9 and a downstream flame zone 10.
• a ceramic insert having the shape according to Fig. 3 was made of a ceramic composite material.
• the material was SiC-fibre/Al 2 0 3 -matrix manufactured by the Dimox®-method by DuPont Lanxide Composites, Inc., USA.
• Said insert was located within a flameholder guide vane such as illustrated in Figs. 3 and 4.
• the guide vane was welded and soldered in the same way as when manufactured without ceramic insert.
• Said metal casing was entirely without openings, i.e. non-cooled.
• the ceramic insert was made without openings or holes.
• the flame holder was mounted in the after burner portion of the turbojet engine. The results of the engine test showed an essentially increased service life and form stability of said flameholder guide vane made according to the invention.
• Example 2 The results of the engine test showed an essentially increased service life and form stability of said flameholder guide vane made according to the invention.
• a ceramic insert with a shape according to Fig. 3 was made of a ceramic composite material.
• the material was SiC-fibre/Al 2 0 3 -matrix made by the Dimox®-method by DuPont Lanxide Composites, Inc., USA.
• the insert was located within a flameholder guide vane such as illustrated in Fig. 3.
• the guide vane was welded and soldered in the same way as when made without ceramic insert.
• the metallic casing was cooled by letting turbine exhaust gases flow through holes in the casing.
• the flame holder was mounted in the after-burner of a turbojet engine. The results of the engine test showed an essentially increased service life and form stability of the flameholder guide vane.
• a ceramic insert of the shape according to Fig. 3 was manufactured in a ceramic composite material.
• the material was C-fibre/Si 3 N 4 ⁇ matrix manufactured by a hot isostatic pressing step (HIP) by ABB Cerama AB, Sweden.
• the insert was placed within a flameholder guide vane such as illustrated in Fig. 3.
• the guide vane was welded and soldered in the same way as when manufactured without ceramic insert.
• the metallic casing was entirely without openings, i.e. non-cooled. Also the ceramic insert was free from holes or openings.
• the flameholder was mounted in the after-burner portion of a turbojet engine. The results of the engine test showed an essentially increased service life and form stability of the flame holder guide vane.
• a ceramic insert in the shape of only the side wall of a guide vane according to Fig. 3 was manufactured in a ceramic composite material.
• the material was SiC-fibre/Al 2 0 3 - matrix manufactured with the Dimox®-method by DuPont Lanxide Composites, Inc., USA.
• the centre volume was filled with a fibre isolating block of aluminium silicate fibre with mul ⁇ lite composition called •-Fiberfrax® 11 , Carborundum, USA.
• the insert was placed within a flame holder guide vane 4 such as illustrated in Fig. 3 of the drawing.
• the guide vane 4 was welded and soldered in the same way as when manufactured without ceramic insert.
• the metallic casing was free from holes, i.e. non-cooled.
• the flame holder was mounted in the after-burner of a turbo-jet engine. The results of the engine test showed an essentially increased service life and form stability of the flameholder guide vane.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Turbine Rotor Nozzle Sealing (AREA)

Applications Claiming Priority (1)

Publications (1)

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Family Applications (1)

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Family Cites Families (4)

• 1994
  • 1994-03-04 JP JP7522849A patent/JPH09511321A/ja active Pending
  • 1994-03-04 WO PCT/SE1994/000191 patent/WO1995023941A1/en not_active Application Discontinuation
  • 1994-03-04 EP EP94913223A patent/EP0748432A1/de not_active Withdrawn

Non-Patent Citations (1)

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