WO2013096989A1 - Rijke type combustion arrangement and method - Google Patents
Rijke type combustion arrangement and method Download PDFInfo
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- WO2013096989A1 WO2013096989A1 PCT/AU2012/001571 AU2012001571W WO2013096989A1 WO 2013096989 A1 WO2013096989 A1 WO 2013096989A1 AU 2012001571 W AU2012001571 W AU 2012001571W WO 2013096989 A1 WO2013096989 A1 WO 2013096989A1
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Classifications
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- 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
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C6/00—Combustion apparatus characterised by the combination of two or more combustion chambers or combustion zones, e.g. for staged combustion
- F23C6/04—Combustion apparatus characterised by the combination of two or more combustion chambers or combustion zones, e.g. for staged combustion in series connection
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C15/00—Apparatus in which combustion takes place in pulses influenced by acoustic resonance in a gas mass
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C3/00—Combustion apparatus characterised by the shape of the combustion chamber
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C6/00—Combustion apparatus characterised by the combination of two or more combustion chambers or combustion zones, e.g. for staged combustion
- F23C6/02—Combustion apparatus characterised by the combination of two or more combustion chambers or combustion zones, e.g. for staged combustion in parallel arrangement
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D2203/00—Gaseous fuel burners
- F23D2203/10—Flame diffusing means
- F23D2203/105—Porous plates
Definitions
- This invention relates to the novel geometrical division of resonant combustors in Rijke type thermo acoustic combusting processes and, in particular, combustion- induced flow oscillating combustors.
- the invention is directed towards Rijke type resonant combustion processes with minimal NOx emission and minimal CO emissions, and increased heat transfer, preferably with application to heat generation- transfer.
- NOx oxides of nitrogen
- SOx sulfur oxide gases
- GO carbon monoxide
- NOx oxides of nitrogen
- Oxides of nitrogen NOx is used to refer to NO and N02.
- NO is the primary form in combustion products (typically 95 percent of total NOx).
- NO is. subsequently oxidized to N02 in the atmosphere.
- Nitrogen oxide formation occurs through three reaction pathe, each having unique characteristics is responsible for the formation of NOx during combustion processes: NOx reduction is the area of most concern today. Thermally produced NOx is the largest contributor to these types of emissions. Thermal NOx is produced during the combustion process when nitrogen and oxygen are present at elevated temperatures.
- NOx is generated by many combustion processes. It combines with other pollutants in the atmosphere and creates 03, a substance known as ground level ozone. Ground-level ozone is serious because it can aggravate asthma and cause lung inflammation and chest pains and has dangerous long-term effects, it is also a key ingredient of urban smog..
- NOx emissions do not form in significant amounts until flame temperatures reach 1500 e C. Once that threshold is passed, however, any further rise in temperature caueee a rapid increase in the rate of NOx formation. NOx production is highest at fuel-to-air combustion ratios of 5-7% 02 (25-45% excess air). Lower excess air levels, in conventional combustion systems, starve the reaction for oxygen and higher excess air levels drive down the flame temperature, slowing the rates of reaction.
- the amplitude is the magnitude of change in the oscillating variable, with each oscillation, within an oscillating system. For instance, sound waves are oscillations in atmospheric pressure and their amplitudes are proportional to the change in pressure during one oscillation. If a graph of the system is drawn with the oscillating variable as the vertical axis and time as the horizontal axis then the amplitude may be measured as the vertical distance between points on the curve.
- Pulsating and oscillating combustion is the consequence of a combustion instabilit that is driven into resonance by the geometry of the burner.
- the resonance is the tendency of a system to oscillate at maximum amplitude at certain frequencies, known as the system's resonance frequencies (or resonant frequencies). At these frequencies, even small periodic driving forces can produce large amplitude vibrations because the system stores vibrational energy.
- the resonance frequency is approximately equal to the natural frequency of the system, which is the frequency of free vibrations.
- Resonant phenomena occur with all type of vibrations or waves. Resonant systems can be used to generate vibrations of a specific frequency, or pick out specific frequencies from a complex vibration containing many frequencies.
- combustion engineers avoid combustion-generated oscillating instabilities at all costs, since they can very quickly lead to catastrophes if the combustion chamber is not designed to capture and transfer the energy of the oscillating combustion.
- Rijke type combustion refers to use of a combustion tube having open ends and a heat source adjacent an inlet end which is heated gauze.
- the Rijke type does not require use of a valve unlike other conventional pulsating and oscillation combustion systems and provides acoustic mode excitation wherein air passing up the tube is heated and expanded producing pulses of air which starts this combustion arrangement or system into oscillation at is natural frequency.
- the present invention provides an efficient and effective means of harnessing Rijke type technology in a novel, and inventive fashion.
- the invention provides in a first aspect a process of producing heat energy for use in heat exchange with other fluids and substances so as to impart said heat energy to said fluids or substances which includes the steps of:
- step (ii) said low pressure area causing partial return of the combusted fuel/oxidant mixture from a location remote of the combustion zone or zones and also causing a new charge of oxidant fuel mixture to be transferred into the combustion zone or zones whereby incoming and returning hot gases are caused to ignite automatically without the aid of the ignition device used in step (i) thereby causing a series of pulses or oscillations of successive return of hot gases and further charges of fuel/oxidant mixture to provide a process of production of energy which is self sustaining and continuous.
- combustion not only includes ignition of the fuel/oxidant mixture with or without flames but also includes detonation and/or deflagration of the fuel oxidant mixture which may take place in a porous membrane adjacent the combustion zone as described hereinafter.
- the combustion zone is separated into an inner and outer combustion zone wherein ignition devices are located in each of the inner and outer combustion zone(s).
- ignition devices are located in each of the inner and outer combustion zone(s).
- the automation ignition occurs at a detonation zone adjacent the combustion zone(s) and the detonation zone may be formed by a porous membrane located in inlet(s) of a planar member having spaces which form part of the combustion zone(s).
- a Rijke type combustion arrangement for use in the process described above having at least one combustion zone having an associated ignition device wherein the or each combustion zone has one or more inlets or entrances and a flame retainer in the form of a porous membrane located in or adjacent to the or each inlet or entrances and there is further provided one or more conveying zones located above the porous membrane for conveying hot gases away from the combustion chamber or space.
- inner and outer combustion zones each having an associated ignition device and a tube assembly having at least two tubes forming a plurality of separate convoying zones or passageways.
- Each tube may have an inner end wherein the inner ends of each of the tubes are each open to a different one of the inner and outer combustion zones and each porous membrane is in fluid communication with an associated inner end of each of the tubes. This arrangement is shown in FIGS 1-7.
- combustion 1 arrangement which only has one conveying zone which is a single chamber located above the porous membrane and a combustion zone located closely adjacent to the porous membrane, which may include the ignition device. This arrangement is shown in FIGS 9-11.
- FIGS 9-11 the description will concentrate on the use of inner and outer combustion chambers as set out in the first embodiment described above.
- each of the tubes is in flow communication with each other at an outlet thereof.
- a planar member adjacent each of the inner and outer combustion chamber having apertures therein which form the inletfs) of the inner and outer combustion zones which may be combustion chambers.
- the apertures are each defined by a cylindrical wall and the flame retainers are located between opposed ends of the apertures.
- the combustion arrangement may also include a frequency adjustment device at each outlet of said at least two tubes as well as adjacent a respective inlet of the inner and outer combustion zones.
- the combustion arrangement may include frequency adjusting sleeves which are movably or slidably mounted relative to the apertures of the planar member thereby to allow adjustment of the inlet orifice depth which is the distance between a lip of the frequency adjusting sleeves and the flame retainers.
- Frequency adjusting sleeves may also be movably or slidably mounted to each tube adjacent an outlet thereof.
- the tube assembly having the said at least two tubes has an even number of tubes, each tube having an internal chamber and wherein half of said internal chambers are open to the inner combustion chamber and the other half being open to the outer combustion chamber.
- the inner combustion chamber and outer combustion chamber are separated by a partition which is continuous and more preferably has a peripheral edge which is serpentine.
- a partition which is continuous and more preferably has a peripheral edge which is serpentine.
- a plurality of tube internal chambers which form an outer set of tube internal chambers and an inner set of tube internal chambers which are concentric with the outer set.
- the inner ends of the outer set of tube internal chambers are open to the outer combustion chamber and the inner ends of the inner set of tube internal chambers are open to the inner combustion chamber.
- the combustion arrangement includes combustion ignition means.
- the combustion ignition means may comprise a spark creator euch as a spark plug or a pilot flame which preferably are located in or adjacent the inner combustion chamber and the outer combustion chamber respectively.
- the combustion arrangement includes a fuel plenum and the inlet(s) of the combustor are open to the fuel plenum.
- the combustion arrangement includes a fuel mixing chamber which is open to the fuel plenum for feeding fuel to the fuel plenum.
- the mixing chamber may have obstructions therein which causes fuel in the fuel mixing chamber to mix as it circulates in the fuel mixing chamber.
- the combustion arrangement may further comprise urging means for forcing fuel and/or oxidant into the fuel mixing chamber.
- the urging means may comprise one or more suitably chosen (with respect to pressure delivery and flow rate) fans or similar arrangement.
- the combustion arrangement may include an inlet acoustic decoupling and/or an outlet acoustic decoupling device.
- the tube assembly has fluid holding arrangements such as tubes or colls placed in at least one of the tubes through which a fluid to be heated may flow.
- the chambers are generally circular in cross-section.
- the tube internal chambers may be square, rectangular, triangular or other shape in cross-section.
- the cross-sectional area of the internal chambers may be constant or, alternatively, may vary.
- the tube internal chambers may therefore be aligned non- vertically; they may be curved or angularly deviated. They may be mono-walled or cavity-walled; they may be non-circular and irregular in cross-section and may vary throughout their length.
- the tube internal chambers may be straight, beht, S-shaped, U-shaped or coiled or otherwise conformed so as to reduce or increase the distance over which the tube internal chamber extends away from the combustor.
- the tube internal chambers may communicate with each other.
- the invention extends to a combustion arrangement further including a substance delivery means for delivering a gas, fluid or other substance to be heated to a heat exchanging surface of the combustion arrangement.
- the substance delivery means may comprise a fan, pump, a belt, a chute, a chamber or other arrangement suitable to maintain the substance in heating contact for a desired period of time, with the heat exchanger surface.
- the substance delivery means comprises a pump or auger-like arrangement to advance the subslance in a desired path or direction.
- One or more combustor arrangements according to the present invention may be located inside a housing, the housing adapted to receive the substance and to circulate around or inside or outside of one or more tube internal chambers to thereby mix the substance and provide even heating throughout.
- Rijke type combustors that are non-vertical provide greater efficiency in heat transfer by decreasing the discharge of heat through the vertical exhaust. Larger areas may be suitably provided for heat transfer. Additionally, the use of modular arrangements allows for complex devices and configurations to be provided for a significant transfer of heat with time. Different shapes facilitate different methods and the use of non-circular Rijke type combustors may also be of considerable advantage.
- the invention actively utilises combustion instability to gain a number of advantages.
- the resonance driving of combustion causes the system to oscillate at maximum amplitude at certain frequencies, locks the combustion instability into a very stable repetitive pattern at the combustor arrangements resonant frequency, which can be anywhere between 15Hz to 20,000Hz, but more frequently lies in 400Hz and 8,000Hz range.
- the burner When the acoustic pressure wave exceeds the pressure drop of the gases through the combustion chamber inlet(s), the burner becomes self-aspirating and there is no need for a fan to continuously supply the combustion mixture.
- the flame is not continuous but a series of discrete flamelete that are ignited on the hot remnant gases of prior flamelets. The invention therefore actively utilises the instability to gain a number of advantages.
- the overall heat transfer and mass transfer coefficients may be two orders of magnitude higher than conventional systems.
- the implications of this are that the size of the equipment can be reduced, i.e. the heat ' transfer area can be more than halved to carry out the same duty as. a forced convection conventional combustion system supplying heat to an industrial process.
- the acoustic pressure wave causes the gases and material in the primary and the tube assembly to oscillate rapidly. This has at least three known effects that cause an increase in the transfer rates:
- the Rijke-type combustor arrangement detailed in thie invention can be made to operate at any orientation. Many variations have been tried and proven by the inventor.
- thermo acouslic or Rijke type combustor arrangement enables heat exchange for hot water or steam production to be done in a more energy efficient manner and with limited NOx emission to the atmosphere.
- the small physical size of the equipment, compared with conventional equipment may allow retrofitting of existing burner systems with a more energy efficient and greener alternative.
- thermo acoustic combustor arrangement enables heat exchange and or sterilisation or pasteurization of soil to be done in situ as a cultivation/sterilisation process in a single operation, which is expected to provide an environmentally friendly and cost-efficient alternative for the horticultural industry.
- the process involves the steaming or heating of the topsoil or growing medium to a temperature of approximately 86°C. This is enough to cause extermination of the pathogenic pests but without heating the soil to levels that are considered harmful to the beneficial nitrogen fixing bacteria, necessary for normal plant growth.
- a soli sterilisation/pasteurisation arrangement may be constructed that can be stationary, tractor mounted or self-propelled. It may process soil at the same time it is tilled.
- FIG 1 shows a perspective view of the Rijke type combustion arrangement in a preferred embodiment in accordance with the invention
- FIG 2 shows an exploded perspective view of the Rijke type combustion arrangement of FIG 1;
- FIG 3 shows a sectional view of the Rijke type combustion arrangement in accordance with the invention
- FIG 4 shows a typical plan view of a divided combustion arrangement
- FIG 5 shows a typical section of the combustion arrangement
- FIG 6 is an exploded perspective view of the combustion arrangement of the invention in a vertical orientation
- FIG 7 is a longitudinal sectional view of the combustion arrangement shown in FIG 6;
- FIG 8 is a perspective view of another embodiment of the Rijke type combustion arrangement of the invention with part of the external skin or casing removed for convenience;
- FIG 9 is an external perspective view of another embodiment of the combustion arrangement shown in FIG 8;
- FIG 10 is a sectional view through line A-A of FIG 9.
- FIG 11 is a perspective view of the combustion arrangement shown in FIGS 9-10 with part of the external skin or casing removed for convenience.
- the Rijke combustion arrangement and method described in the present application provides for complete combustion of a combustible gas mix and preventing or limiting the emissions of oxides of nitrogen NOx.
- a Rijke type thermo acoustic combustion arrangement 10 having a cylindrical body 37 and fuel oxidant inlet end 50 and an exhaust end 54.
- a support frame 49 having a pair of beams 47 and 48 for supporting body 37 in a vertical orientation wherein each beam 47 and 48 contacts the ground (not shown).
- peripheral plate 46 welded to beams 47 and 48 and attached to body 37 by fasteners 45.
- fixed conduit or tube 60 having inlet 53 for fuel and inlet 51 for oxidant whic each have peripheral mounting flanges 44 for attachment to a source of fuel (not shown) and oxidant (not shown).
- Plate 46 is integral with or attached to cylindrical inlet body mixing tube 52.
- inlet body 52 has a central plate 28 for attachment to corresponding central plate 33 by fasteners 42 wherein fuel oxidant plenum 40 surrounds plate 28.
- exhaust body or tube 41 and peripheral end plate 55 shown in FIGS 2 and 6 attached to end plate 12 shown in FIG 6 by fasteners 13 shown in FIG 1 passing through aligned apertures 13A and 3B also shown in FIG 6.
- observation tubes or ports 62 and mounting plates 63 and 64 made of mesh for observation tubes 62.
- Exhaust tube 41 also has mounting flange 65 for attachment to plate 64 by fasteners 67.
- the feed conduit or tube 60 may be in fluid communication with the fuel or oxidant source with the agency of a fan, pump or other device that may include a valve assembly and regulating system (not shown) which controls the amount of oxidant or fuel fed into feed conduit 60.
- Both plates 63 and 64 are also in the nature of screens formed from mesh as described above for screen 58.
- Also as best shown in FIG 6 there is also provided a central plate 17A having a set of inlet apertures 16A for cold water entering tubes 30 shown in FIG 7 and a set of outlet apertures 17 for hot steam exiting through tubes 30.
- FIG 2 which shows the interior of body 37 there is provided a combustor 12 and a tube assembly 14.
- the combustoY 12 is divided into an outer combustion zone or chamber 16 and an inner combustion zone or chamber 18.
- the outer combustion chamber 16 and the inner combustion chamber 8 are divided by a continuous serpentine partition wall 20 having a serpentine shape as shown in FIG 4.
- the outer combustion chamber 16 is surrounded by a peripheral wall 32 also shown in FIG 4 which is attached to adjacent peripheral flange 31 of mixing tube 52 by fasteners 29.
- central disc 33 which is concentric with the surrounding Circular wall 32 and is located at the centre of the inner combustion chamber 18.
- the tube assembly 14 comprises geometrically arranged tubes 22.
- the tubes 22 are arranged in a ring.
- the tubes 22 have inner ends 38 at their fuel/oxidant inlet ends shown in FIG 5.
- the combustor 12 and the internal chambers of tube assembly 14 are in communication with each other as will be discussed in more detail herein- below.
- the combustor 12 has planar member 26 with a number of geometrically arranged apertures 24 therein, which define fuel/oxidant inlets 66 to the combustor 12 as shown in FIG 5.
- the apertures 24 in planar member 26 have opposed recesses 26A which determines the thickness of porous membranes 28.
- the wall 20 meanders between the apertures 24 so that adjacent apertures 24 are alternatively in the outer combustion chamber 16 and the inner combustion chamber 18. Flame retainers in the form of porous membranes 28 are located in the apertures 24 as also shown in FIG 5.
- the combustor 12 includes frequency adjusting sleeves 56 shown in FIG 5 which are screw-threadingly fixed inside the apertures 24.
- the frequency adjusting sleeves 5 ⁇ are displaceable towards and away from the porous membranes 28, thereby varying the distance from an inlet lip 48 of the sleeves 56 to the porous membrane 28. This distance is referred to as the inlet orifice depth (a).
- the porous membrane 28 is of ceramic or metallic mesh.
- the membrane has. a preferred thickness (r) of 1-10mm.
- the porous membrane 28 is provided in the flow path 42 of the fuel/oxidant mixture to be burnt ehown in FIG 3.
- the membrane 28 allows a controlled charge of the combustible fuel/oxidant mixture into the primary combustor 12 to be ignited whereby the membrane 28 provides resistance and partial closure, thereby preventing backflow under back pressure from the combusted fuel in the combustor 12 until, on reduction of back pressure due to exhaust of combusted- gas, the pressure drop at the inlet 66 is sufficient to allow again fuel access to the combustor 12.
- This cycle is repetitively executed so that combustion occurs in a continuous rhythmic or pulsing fashion.
- the combustor 12 communicates with fuel/oxidants plenum 40 via the porous membrane 28.
- the membrane 28 may be formed from thin filaments of sintered metal for example non woven FeCrAI alloy steel. They have very high porosity between 80-90% and have very high flow rates i.e. up to 20 times higher than the conventional media. The membrane 28 is very strong and can be used in temperatures up to 300 e C.
- the inner ends 38 of the tubes 22 are each in register with a different aperture 24.
- the outlets 23 of the tubes 22 at their distal ends from inlets 38 are surrounded by frequency adjusting sleeves 36 as shown in FIGS 2 and 3.
- the sleeves 36 are slidingly adjustable on the tubes 22.
- the sleeves 36 abut each other.
- the fuel/oxidant plenum 40 is open to the fuel/oxidant mix from mixing chamber 52.
- the fuel/oxidant plenum 40 and the mixing chamber 52 is separated by the fuel diffusing screen 58.
- Geometrically formed blocks of material (not shown) are inserted into the fuel and oxidant mixing chamber 52 to disturb flow of fuel and oxidant in the chamber 52 to enhance uniform mixing of the fuel and oxidant in the chamber 52.
- the walls 20, 32, 33 are oriented normal to the mean flow direction 42 of the fuel and oxidant shown in FIG 3.
- the combustor 12 is capable of resonant type operation over a wide range of frequencies. It is envisaged that extension of the range of acoustic resonant frequencies in an embodiment can be obtained by additionally forming the wall 32 and/or 33 in a curved or serpentine configuration. Unlike other Rijke-type combustors the preferred embodiment of this combustor arrangement described is capable of operation over a wide range of operating frequencies and firing rates, particularly under differing conditions of density of the fuel/oxidant mixture.
- the described chamber separation walls and shape enables increased firing rates (i.e. thermal input) compared with the prior art. It has been observed that, with the geometrically divided combustor 12 and tube assembly 14, once operational the outer combustion chamber 16 and inner combustion chamber 18 tend to seek a common operating frequency, and are out of phase so that acoustic noise generated is at least to some extent cancelled through destructive source pressure addition. It is not necessary in this case to take special steps to particularly tune the combustor arrangement to any resonant frequency, since, as mentioned, the combustors automatically tend to settle at a common operating frequency while operating in and out of phase as described above.
- the common operating frequency can be adjusted by the sleeves 56 connected to the inlet 66 of the combustor 12 and the adjustable sleeves 36 of the tube assembly 14.
- the use of the frequency adjustment sleeves 56 and 36, if provided as abutting tubes may give more precise control over the acoustic output of combustion arrangement 10..
- the wall 20 separating the two combustion chambers 16, 18, exhibit a continuously changing serpentine-like curvature over its length, with the centre of curvature alternating between the outer and inner combustion chambers 16, 18. Inwardly and outwardly curving portions of the wall 20 have differing curvature.
- the wall 32 defining the outside of the primary combustor may be curved or circular or have straight portions.
- the central wall 33 may be curved or circular or have straight portions.
- mesh plate 63 may be attached to mesh plate 64 and there is also shown adjustment sleeves 36 which are all welded to support plate 57.
- spiral tubes 30 which may be located in the internal chambers of tubes 22 as shown in FIG 7.
- Each tube 22 has an outlet part or end 23 engageable with an associated adjustment sleeve 36 by fasteners 25.
- support plate 21 for supporting exhaust decoupling assembly 34.
- inlets 38 are each alternatively in fluid communication with chambers 16 or 18.
- Each tube 22 is also attached to a mounting plate 57A which has attachment apertures 61 for engagement with peripheral plate or ring 32 as well as peripheral plate or ring 29.
- each tube 22 has located therein a spiral tube 30 shown in FIG 7.
- Cold water is introduced into tubes 62A adjacent outlet end 54 which then travels through branched portion 63 before entering spiral tubes 30.
- the cold water is heated by the combustion gases within each tube 22 having an internal chamber 22A in heat exchange relationship with spiral tubes 30. Then the water may exit tubes 30 through conduits 63A and 63B and the heated water exits through outlets 17.
- FIG 7 also shows a fixed sleeve ⁇ 9 ⁇ screw-threadedly engagable with outer sleeve 69 which may be adjusted at adjustment member 70 to move each adjustment sleeve 36 closer to inlet end 50 or further away from inlet end 50 as may be required.
- Tube 69 has end projection 15.
- a central cylindrical body 71 for supporting each tube 62A and 63B and fixed sleeve 69A.
- bracing members 72 There is also shown fasteners 19 for observation tubes 62.
- inner space 74 surrounded by inlet conduits 52A for fuel/oxidant mixture. Inner space 74 accommodates central plate 28.
- the mixture of combustible gas will pass through the mixing chamber 52 into the fuel and oxidant plenum 40 which is in communication with combustor 12 via the fuel porous membrane 28.
- a charge of fuel and oxidant mixture passes through the fuel porous membrane 28 into the combustor 12 to be combusted.
- an ignition device 53A such as a sparkplug or pilot burners known to a person skilled in the art in each of the combustion chambers 16, 18 as shown in FIG 6.
- the combustion of the fuel/oxidant mix causes the mixture to burn and the hot gases causes a sudden increase in volume and pressure in the primary combustor 12, as the hot gases expand in the direction of the tube assembly 14.
- the pressure wave caused by the combustion causes the combusted fuel mix to travel into the tubes 22 with significant momentum and thereby creating a low pressure zone in the combustor 12.
- This low pressure zone causes the partial return of the combusted fuel/oxidant mixture from the tube assembly 14 into the combustor 12 and a new charge of fuel/oxidant mixture from the plenum 40 into the combustor 12.
- the incoming and the returning gasee collide and mix and the returning hot gases are above the auto ignition temperature of the incoming gas/oxidant mixture.
- the auto ignition of the gas mixture will then take place and the system etarte to oscillate and the cycle repeats itself.
- the tube assembly 14 may communicate with an exhaust decoupling chamber 34.
- the tubes 22 of the tube assembly 14 are positioned in alternative arrangement to the outer and inner combustion chambers 16 and 18.
- the tubes 22 are alternately open to the outer and inner combustion chambers 16, 18 in an arrangement wherein if one of the tubes is open to the outer combustion chamber 16 then the two tubes adjacent it are open to the inner combustion chamber 18.
- the frequency adjusting sleeves 36 and 56 are arranged so that the combustor 12 and tube assembly 14 are in direct communication with each other. If tuned out of phase the acoustic waves generated in the combustor 12 and tube assembly 14 propagate towards and into the exhaust decoupling device 34 and tend to cancel each other in operation within the exhaust decoupling device 34 and thereby diminish the sound production and emission of the combustion arrangement 0.
- combustion arrangement 10A having body or casing 80, heating coils 81 and 82, wall structures 83 and 84 for supporting coils 81 and 82, and intermediate wall structure 85 also for supporting coils 81 and 82 wherein each of structures 83, 84 and 85 each have nollow interiors defining water jackets 86, 87 and 88.
- a length adjustment member 89 which determines the frequency of the heat pulses that are propagated in combustion arrangement 10A.
- fuel plenum 90 which is surrounded by support frame 91.
- exhaust opening 92 cold water inlets 93 and 94 and hot water outlets 95 and 96.
- porous membranes 97, combustion zones 98 which each have an ignition device (not shown), and hot water return conduits 99.
- heat pulses are caused to travel through the interior of passageways 100 and 101 which surround heating coils 81 and 82 and return pulses are detonated by porous membrane 97 and then pushed upwardly through passageways 100 and 101 causing a cyclic series of pulses which heat up water contained in coils 81 and 82 for ultimate exit of combustion arrangement 10A through outlets 95 and 96.
- hot water from water jackets 86, 87 and 88 may also be preheated by coils 81 and 82 before being passed to inlets 93 and 94 by suitable conduits (not shown).
- FIGS 9-11 there is shown another combustion arrangement 0B of the invention which has a body or housing 105, exhaust gas opening 100, support frame or base 107. water inlet 108 and water outlet 109. There is also shown a releasable cover 110 releasably attached to body 105 by fasteners 111 and a releasable side component 112 attached to body 105 by fasteners 113. There is also provided fuel plenum 114, preheater fuel cavity 115 and inlet 116 for entry of fuel/oxidant into passageway 117.
- body 105 In combustion arrangement 0B fuel/oxidant mixture enters body 105 through inlet 116 and passes through passageway 117 and down fuel cavity 115 to fuel plenum 114 as shown by the arrows in bold. There is also provided water jacket 118 and feed ipes 119 for water jacket 116.
- Body 105 also has a pair of hollow interiors or chambers 120 shown in FIG 11 which is occupied by spiral tubes or heating coils 121.
- combustion zones 122 which each has an ignition device (not shown) ae well as poroua membrane 123. Also shown is horizontal water return conduit 124 which communicates with inlet 108 and horizontal conduit 125 which communicates with outlet 109.
- the chambers 120 form the conveying zones for conveying hot gases away from the combustion zone 122.
- porous membranes 97 and 123 are located in an inlet to combustion zones 98 and 122.
- the inlet or inlet opening is shown as 131 in each zone 98 and 132 in each zone 122.
- a further advantage of the combustion arrangement 10, 10A and 10B resides in the effectiveness of the combustion method of the invention and combustor 12, 98 and 22 in particular to the ability to maintain flames at high combustion efficiencies with low NOx and pollutant emissions. All aspects are closely related to the flow characteristics inside the combustion chamber and the degree of mixing obtained with the combustible gas and the oxidants.
- the mixing involves several important processes. Large-scale structures bring into the mixing layer large amounts of reacting components from the separate reactants. The fine-scale eddies enhance the mixing at a molecular level between the reactants which is a necessary condition to initiate the complex sequence of exothermic chemical reactions between a fuel and an oxidant. When the flame propagates in a non-uniform flow it experiences strain and curvature effects.
- the fractional rate of change of the flame area constitutes the flame stretch.
- the flame stretch parameter determines the available flame surface density and consequently the reactivity of the fuel and oxidants. Stretching of the flame and the body of the flame also controls some of the mixing and consequently the emission of pollutants. Large flame stretching parameters generally lead to lower temperatures and modified residence times of the reactants in the burning zone and hence reduced emissions of thermally generated NOx.
- the modification of the flame stretch can be achieved by modification of the fluid dynamics.
- the combustors and combustion chambers and method in accordance with this invention facilitate very high rates of flame stretch, while at the same time sweeping up the remnants of the flamelets and returning them to be incorporated into the next flamelets. This also causes a micro form of exhaust gas recirculation, which is known to a person in the art, to dramatically reduce or prevent unwanted emission, particularly NOx.
- the continual recycling of flamelets allows much longer residence times fbr reactions to take place.
- Very high flame stretch also reduces radicals in the flame. These radicals are parts of molecules, e.g. -CH and -OH, that can exist at the higher temperatures encountered in flames. Most of these radicals are responsible for much of the pollutant formation.
- the situation is further improved by the very high degree of mixing that is generated.
- the pollutant forming reactions tend to be greater than 1st order, which get slowed upby increased mixing, where as the desirable reaction, which tend to be less than 1st order, get speeded up.
- the combination of these effects leads to the very clean low pollution combustion.
- the geometry of the combustor 12 facilitates the emission of oxide of nitrogen NOx and carbon monoxide CO to be eliminated or reduced to levels less than 1 ppm from the combustion processes, by introduction of the geometrical division 20 between the outer and inner combustion chambers 16, 18, thereby facilitating the combustion of combustible gases in such a manner that oscillation and flame stretching occurs within the porous membrane 28.
- the partition 20 of the primary combustor 12 causes the primary combustor 12 to oscillate a different frequency from the secondary combustor 14.
- the correct -aspect ratio is chosen to match the fundamental harmonic frequencies generated by the length and geometry of the Rijke type combustor arrangement. This is achieved by ensuring that the major length of the combustors (L) is a whole number multiple of both the inlet orifice depth (a), the flame retainers thickness (f) and the fundamental harmonic oscillation frequency ( ,) whereas the inlet orifice depth is a- ⁇ ( 1 ⁇ 2 L'n/ ⁇ ) - (50 * t) ⁇ /100 where n - the number of nodes..
- the major length of the combustors L is the distance from the inlet lip 48 to the top of the adjusting sleeves 36.
- This invention is directed towards the achievement of pulsing or rhythmic combustion that causes oscillation of gases and fuel flow, which subsequently causes the flame to stretch, within the boundary limit of the porous membrane or flame retainer 28, and the prompt NOx to be suppressed, which result in the reduction of the prompt NOx radical reactants, and the exhaust gas recirculation within the flame zone, which biases the prompt NOx reactions to go in reverse directions, thus stopping any further NOx from being produced.
- This NOx is trapped in the flame within the porous membrane 28, and does not exit.
- the NOx levels within the flame area can be quite high even though the net emission is ero.
- the use of the present combustor arrangements for the production of steam or hot fluid directly addresses the looming problem of greenhouse gas emissions and energy conservation.
- the devices may, of course, also be used for generating of heat for the purpose of hot water, steam, organic fluids and gasses or conditioning soil and seed for storage to avoid insect damage, fungal growths and other pathogens, and enhancing the safety of supplies in the food chain.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US14/368,825 US20140360203A1 (en) | 2011-12-29 | 2012-12-21 | Rijke type combustion arrangement and method |
AU2012363345A AU2012363345A1 (en) | 2011-12-29 | 2012-12-21 | Rijke type combustion arrangement and method |
IN5726DEN2014 IN2014DN05726A (en) | 2011-12-29 | 2014-07-10 |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2011905453A AU2011905453A0 (en) | 2011-12-29 | Rijke type combustion arrangement and method | |
AU2011905453 | 2011-12-29 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2013096989A1 true WO2013096989A1 (en) | 2013-07-04 |
Family
ID=48696113
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/AU2012/001571 WO2013096989A1 (en) | 2011-12-29 | 2012-12-21 | Rijke type combustion arrangement and method |
Country Status (4)
Country | Link |
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US (1) | US20140360203A1 (en) |
AU (1) | AU2012363345A1 (en) |
IN (1) | IN2014DN05726A (en) |
WO (1) | WO2013096989A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN113125503A (en) * | 2021-04-12 | 2021-07-16 | 西北工业大学 | Measurement method of thermoacoustic instability experimental system for measuring propellant combustion response |
CN114543984A (en) * | 2022-04-22 | 2022-05-27 | 北京航空航天大学 | Quantitative adjusting device and method for Rijke tube boundary dissipation |
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US4199936A (en) * | 1975-12-24 | 1980-04-29 | The Boeing Company | Gas turbine engine combustion noise suppressor |
US4808107A (en) * | 1987-05-05 | 1989-02-28 | Paloma Kogyo Kabushik Kaisha | Pulse combustion system |
EP0537732A1 (en) * | 1991-10-18 | 1993-04-21 | Paloma Kogyo Kabushiki Kaisha | Electric control system for pulse combustion device |
GB2297830A (en) * | 1995-02-07 | 1996-08-14 | Rolls Royce | Radially staged annular combustor |
US5588822A (en) * | 1994-07-01 | 1996-12-31 | Paloma Kogyo Kabushiki Kaisha | Flame trap for use in a pulse combustor |
WO2004031651A2 (en) * | 2002-10-01 | 2004-04-15 | Powertech Industries Inc. | Multiple plate combustor |
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US4080149A (en) * | 1976-04-01 | 1978-03-21 | Robertshaw Controls Company | Pulse combustion control system |
US4314444A (en) * | 1980-06-23 | 1982-02-09 | Battelle Memorial Institute | Heating apparatus |
GB8329218D0 (en) * | 1983-11-02 | 1983-12-07 | Ffowcs Williams J E | Reheat combustion system for gas turbine engine |
US5176513A (en) * | 1990-12-04 | 1993-01-05 | Georgia Tech Research Corporation | Pulse combustor apparatus |
US20120204814A1 (en) * | 2011-02-15 | 2012-08-16 | General Electric Company | Pulse Detonation Combustor Heat Exchanger |
-
2012
- 2012-12-21 AU AU2012363345A patent/AU2012363345A1/en not_active Abandoned
- 2012-12-21 WO PCT/AU2012/001571 patent/WO2013096989A1/en active Application Filing
- 2012-12-21 US US14/368,825 patent/US20140360203A1/en not_active Abandoned
-
2014
- 2014-07-10 IN IN5726DEN2014 patent/IN2014DN05726A/en unknown
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
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US4199936A (en) * | 1975-12-24 | 1980-04-29 | The Boeing Company | Gas turbine engine combustion noise suppressor |
US4808107A (en) * | 1987-05-05 | 1989-02-28 | Paloma Kogyo Kabushik Kaisha | Pulse combustion system |
EP0537732A1 (en) * | 1991-10-18 | 1993-04-21 | Paloma Kogyo Kabushiki Kaisha | Electric control system for pulse combustion device |
US5588822A (en) * | 1994-07-01 | 1996-12-31 | Paloma Kogyo Kabushiki Kaisha | Flame trap for use in a pulse combustor |
GB2297830A (en) * | 1995-02-07 | 1996-08-14 | Rolls Royce | Radially staged annular combustor |
WO2004031651A2 (en) * | 2002-10-01 | 2004-04-15 | Powertech Industries Inc. | Multiple plate combustor |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN113125503A (en) * | 2021-04-12 | 2021-07-16 | 西北工业大学 | Measurement method of thermoacoustic instability experimental system for measuring propellant combustion response |
CN113125503B (en) * | 2021-04-12 | 2023-09-26 | 西北工业大学 | Measurement method of thermoacoustic instability experiment system for measuring combustion response of propellant |
CN114543984A (en) * | 2022-04-22 | 2022-05-27 | 北京航空航天大学 | Quantitative adjusting device and method for Rijke tube boundary dissipation |
CN114543984B (en) * | 2022-04-22 | 2022-07-05 | 北京航空航天大学 | Quantitative adjusting device and method for Rijke pipe boundary dissipation |
Also Published As
Publication number | Publication date |
---|---|
IN2014DN05726A (en) | 2015-04-10 |
AU2012363345A1 (en) | 2014-07-24 |
US20140360203A1 (en) | 2014-12-11 |
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