Abstract: For the purpose of reduced NOx gas emission, a gas turbine engine comprises a cylinder having a combustion region inside of the cylinder; a resonator having a cavity and provided around the surface of the cylinder and sound absorption holes formed on the cylinder and having opening ends on the cylinder.

Abstract: A combustion chamber according to the invention has a number b0 of annularly arranged burners, of which a number k of modulatable burners have means for modulating a fuel mass flow, k being k<b0, and the modulatable burners being arranged in such a way that between every pair of adjacent modulatable burners are arranged in each case a1, a2, . . . ak nonmodulatable burners, and that the values a1+1, a2+1, . . . , ak+1 are not integral divisors of b0. In a preferred embodiment of the invention, a highest value of LCM(b0, a1+1), LCM(b0, a2+1), . . . LCM(b0, ak+1) is maximum, LCM designating the lowest common multiple. It thereby becomes possible to damp a maximum number of azimuthal vibration modes of the combustion chamber by means of a minimum number of modulatable burners. Each pair of modulatable burners gives rise to at least one undesirable vibration or instability which, however, is damped by the other modulatable burner or burners arranged according to the invention.

Abstract: In a combustion chamber arrangement, especially an annular combustion chamber arrangement for a gas turbine, one or more burners has, at its mouth, a deflecting device by which a combustion chamber arrangement is deflected. This achieves the effect of acoustic detuning, whereby the formation of a combustion oscillation is suppressed.

Abstract: The invention relates to a damper arrangement for reducing combustion-chamber pulsations arising inside a gas turbine (1), having a combustion-chamber housing (8) which upstream comprises a front plate (2) with a plurality of individual burners (6) and damping elements (7, 7a, 7b) projecting through the front plate (2) and downstream is connected to a turbine stage (9) and is surrounded by a turbine housing (3) which comprises first openings (5a) which are adapted to the burners (6) and through which the burners (6) project upstream. The invention is characterized in that closable second openings (5b), through which it is possible to insert and tune the damping elements (7, 7a, 7b), are provided inside the turbine housing (9) adjacent to the first openings (5a) adapted to the burners (6).

Abstract: A resonator module for a combustion turbine power plant, where the combustion turbine power plant defines a flow path. The resonator module includes a first member, an a second member. The first member has a size substantially smaller than the diameter of said flow path and a plurality of openings therethrough. The openings are in fluid communication with the flow path. The second member has a size generally equal to said first member. The second member is in a generally spaced relation to the first member and encloses a volume of gas between the first and second members.

Abstract: An electronic gas-lighting device (1) having a casing (2) made of insulating material and defined by a cup-shaped body (6); electronic high-voltage-pulse generating means (3) housed in an inner cavity (7) of the casing (2) and including noise suppressing means (4) in turn including a ground connection (26); and assembly means (5) for removably fitting the casing (2) to a supporting surface of a metal conducting body element of an electric household appliance, in particular, a cooking range with gas burners. The ground connection (26) is defined by an elastically deformable conducting element (27) which is connected electrically to the noise suppressing means (4), projects outside the cavity (7) on the same side as the assembly means (5), and is so formed as to be interposed, in use, between the casing (2) and the supporting surface and gripping between the casing (2) and the metal conducting body element by means of the assembly means (5).

Abstract: A burner box assembly for a combustion air furnace includes a back wall, opposed side walls and top and bottom walls defining an interior space for one or more burner nozzles. A combustion air inlet opening is formed in the top wall and is covered by a generally rectangular inverted channel-shaped airflow guide and baffle member. A second generally rectangular box-shaped louvered airflow guide and baffle member is mounted on the interior side of the top wall over the combustion air inlet opening for distributing the flow of combustion air into the burner box assembly and to reduce acoustic emissions from the burner box assembly through the combustion air inlet opening. The combination of the louvered baffle member and the exterior mounted baffle member provides reduced acoustic emissions from the burner box assembly as well as more evenly distributed combustion airflow into and through the burner box assembly.

Abstract: In a burner (10) for the production of a hot gas, which burner (10) opens with a burner outlet (22) edged with an outlet edge (16, 17) into a combustion chamber (23), in which a fuel-air mixture flowing out from the burner outlet (22) with the formation of an outflow boundary layer (18′) forms a flame (20) after the ignition of the burner (10), the combustion process is improved in that, to prevent periodic releases of heat and the therewith connected thermoacoustic oscillations in the combustion chamber (23), means (21) are arranged at the burner outlet (22) for changing the thickness of the outflow boundary layer (18′).

Abstract: In a method of controlling thermoacoustic vibrations in a combustion system having a combustion chamber and a burner, the fluid shear layer forming in the region of the burner is acoustically excited. An apparatus for controlling thermoacoustic vibrations in a combustion system having a combustion chamber and a burner is distinguished by the fact that device(s) for the acoustic excitation of the working gas are arranged in the region of the burner.

Abstract: In a method of suppressing or controlling thermoacoustic vibrations which develop in a combustion system having a burner working in a combustion chamber due to the formation of coherent or vortex structures and a periodic heat release associated therewith, in which method the vibrations are detected in a closed control loop and acoustic vibrations of a certain amplitude and phase are generated as a function of the detected vibrations and induced in the combustion system, improved suppression is achieved in that, within the control loop, the amplitude of the generated acoustic vibrations is selected to be proportional to the amplitude of the detected vibrations.

Abstract: The invention refers to a combustion chamber device including a combustion chamber (2) and a set of burners (6) with an outlet opening (7) in the combustion chamber. Each burner includes members (10) for the supply of a flow of oxygen-containing gas, members (8) for the supply of fuel, and a space (9), which extends to the combustion chamber (2) for mixing of the fuel and the oxygen-containing gas. Each burner (6) is arranged to convey a substantially equally large flow of oxygen-containing gas through the burner to the combustion chamber. Each burner (6) is defined by at least one parameter including a characteristic length (a) of the space (9) along the longitudinal direction (x). At least the characteristic length (a) of at least one of the burners is selected in such a way that it deviates from the corresponding length (a) of another burner and in such a way that the influence of the oscillations which arise during operation of the combustion chamber device are reduced.

Abstract: A burner apparatus includes a foraminous burner surface having a multitude of openings through which flames can extend. The burner surface is irregularly shaped so that flames extending from the openings are directed in an irregular pattern whereby eddy currents are generated and effectively disrupt oscillation of the flames to result in reduced noise generation from flame oscillation.

Abstract: In a method of, and an appliance for, operating a burner (26), in which a combustion air flow (14) transports fuel into a combustion chamber (28) where the fuel is burnt, the formation of coherent flow instabilities of the combustion air flow (15) after emergence into the combustion chamber (28) is prevented by perturbation air (22) being injected into the combustion air flow (15).

Abstract: A damping device for reducing the vibration amplitude of acoustic waves and a burner for operating an internal combustion engine, the burner having a mixing region, in which an air flow and a fuel flow are mixed with one another to form an air/fuel mixture, and a combustion chamber, which in the direction of flow of the fuel/air mixture is arranged downstream of the mixing region, in which the fuel/air mixture can be ignited. A Helmholtz resonator directly connected to the mixing region of the burner such that acoustic waves formed in the burner are suppressed in the Helmholtz resonator and are not reflected back into the burner.

Abstract: The invention relates to a heating device, especially for a motor vehicle, with a burner, to which fuel is supplied from a tank via a fuel line by means of a pump, especially a piston pump, and with an electronically controllable valve means which is inserted into the fuel line and which can be controlled by a control means. To ensure problem-free feed of fuel to the burner independently of the pump pressure, a pressure reservoir is assigned to the valve means, fuel being delivered by means of the pump controlled in a clocked manner by the control unit, to the pressure reservoir and from the latter to the burner, without the action of the pump.

Abstract: A method of detecting combustor dynamic pressures in combustors of a gas turbine combustor includes the steps of: a) mounting at least one accelerometer (24) on a combustor casing; b) establishing a baseline vibration signature for the casing when combustion dynamics are minimal; and c) measuring subsequent vibration signatures and comparing those signatures to the baseline signature.

Abstract: A method for active suppression of hydrodynamic instabilities in a combustion system in which liquid or gaseous fuel is premixed with combustion air and the fuel/air mixture is then burnt. The mass flow of the supplied fuel is modulated on the basis of a selected time function. Simplification and increased functional reliability are achieved by the modulation which is carried out using fluidics.

Abstract: In a method for burning a liquid fuel in a combustion system (10) which comprises a combustion chamber (11) and at least one injection nozzle (13) through which liquid fuel is injected into the combustion chamber (11) in the form of a fuel spray (16) and is burnt there with combustion air being added, disturbance-free operation in a simple manner is distinguished in that, in order to actively suppress hydrodynamic instabilities in the combustion chamber (11), the injected fuel spray (16) is modulated by having an electrical voltage applied to it during the injection process, governed by a selected time function.

Abstract: In a burner (14) with at least one fuel supply system (15, 16) through which the burner (14) is fed a fuel flow (12), and the fuel fed is injected via fuel nozzles and subsequently burned in a combustion chamber (11), the formation and amplification of pressure fluctuations in the combustion chamber is prevented in a simple way in terms of design by virtue of the fact that means (17) are provided which prevent periodic pressure fluctuations which occur in the combustion chamber from leading to fluctuations in the fuel flow (12) in the fuel supply system (15, 16).

Abstract: In a method and an appliance for operating a burner (19), in which a flow of combustion air (10) transports fuel into a combustion chamber (21) where the fuel is burnt and, during transport, the flow of combustion air (10) is mixed with the fuel and guided by casing elements (13, 16), the resonant build-up interaction of coherent flow instabilities and acoustic field is reduced because the formation of first periodic, coherent flow instabilities in a boundary layer between the combustion air (10) and the casing elements (13, 16) is perturbed, and coupling of an acoustic field in the combustion chamber (21) to such first flow instabilities is reduced.

Abstract: A combustor comprises an outer combustor casing defining a plurality of circumferentially adjoining combustion chambers. Each combustion chamber comprises a dome at an upstream end and an outlet at a downstream end. A plurality of pre-mixers are joined to the combustor dome of each respective combustion chamber. The pre-mixers comprise a duct having an inlet at one end for receiving compressed air, an outlet at an opposite end disposed in flow communication with the combustion chamber and a swirler disposed in the duct adjacent the duct inlet for swirling air channeled therethrough. A fuel injector is provided for injecting fuel into the pre-mixer ducts and for mixing with the air in the ducts for flow into the combustion chamber to generate a combustion flame at the duct outlets.

Abstract: A method for the active damping of combustion oscillation in a combustion chamber uses at least two actuating members. Control of the actuating members necessitates measurement of the combustion oscillation at fewer points than there are actuating members. That is achieved, in particular, by utilizing the symmetry of natural acoustic oscillation in the combustion chamber. A combustion apparatus is also provided.

Abstract: An apparatus and method of applying active, closed loop control to reduce combustion driven pressure oscillation in a single or multi-chamber combustion system in an industrial gas turbine, to increase operability and life of the parts, and in such a way as to require minimal input power. The invention combines the passive control of a two stage nozzle with active control thereby to reduce the requirements on the control device. This allows selection of a control device which will have an adequate life in an industrial environment and yet require minimal input power.

Abstract: A method and a device for acoustic modulation of a flame through the use of an acoustically modulated feeding of a fuel. The flame is produced by burning the fuel in a hybrid burner including a premixing burner and a pilot burner associated with the latter. The fuel is fed to the premixing burner in a main flow and to the pilot burner in a pilot flow. The pilot flow is modulated and the main flow is not modulated. The invention is of particular interest for suppressing combustion oscillations in a combustion chamber to which the hybrid burner is connected.

Abstract: A burner for generating a hot gas including at least two hollow partial bodies stacked inside each other in a downstream air flow direction. The center axes of the hollow bodies extend offset to each other such that burner slits formed by adjoining walls of the partial bodies form tangential air inlet channels for an inflow of combustion air into an inside chamber defined by the partial bodies. The hollow bodies are provided with a plurality of baffles projecting into the downstream air flow. The plurality of baffles add an axial turbulence force to the air flow.

Abstract: In a gas turbine having a device for the fuel injection, which injects fuel into a mixing device (12), the injected fuel being mixed with combustion air in the mixing device (12), and in which the gas turbine also has a combustion chamber (16) arranged downstream of the mixing device (12), the length of the combustion chamber being LBK and the length of the mixing device being LMix, in order to suppress thermoacoustic vibrations the premix combustion chamber (10) containing the combustion chamber (16) and the mixing device (12) is designed in such a way that an acoustic pressure fluctuation which occurs in the premix combustion chamber (10) at the combustion-chamber outlet (20) is superimposed in phase opposition on an entropy-wave-induced pressure fluctuation at a certain frequency to be damped.

Abstract: In an annular combustion chamber for a gas turbine, a combustion-chamber dome (14) is arranged upstream of an air-cooled combustion chamber (10). A first portion of an air flow (46) which comes from the compressor is admixed as combustion air to the combustion operation and cooling ducts (22; 24) feed a second portion of the air flow (46) coming from the compressor as cooling air into the combustion chamber (10). In this case, the cooling ducts (22; 24), which run at least in sections along the combustion chamber (10), have an entry (23; 25) into the combustion-chamber dome (14). The cooling ducts (22; 24) are designed for damping combustion-chamber oscillations in such a way that the acoustic impedance at the entry (23; 25) of the cooling ducts (22; 24) into the combustion-chamber dome (14) is minimized.

Abstract: A low NOx combustor and method improve dynamic stability of a combustion flame fed by a fuel and air mixture. The combustor includes a chamber having a dome at one end thereof to which are joined a plurality of premixers. Each premixer includes a duct with a swirler therein for swirling air, and a plurality of fuel injectors for injecting fuel into the swirled air for flow into the combustion chamber to generate a combustion flame therein. The fuel injectors are axially staged at different axial distances from the dome to uncouple the fuel from combustion to reduce dynamic pressure amplitude of the combustion flame.

Abstract: An enclosure surrounding the burner of a furnace, including a top panel, a rear panel, a bottom panel, a front panel, and first and second side panels. An air inlet is provided in one of the panels. A baffle is provided within the enclosure and extends between two opposed panels, each of the opposed panels adjacent the panel having the inlet. A chamber is partly defined by the baffle, the inlet opening into the chamber. The chamber is provided with a vent through which the inlet is in fluid communication with the burner.

Abstract: A gas burner is provided for use on the inlet end of a fire tube, and includes a mixer having attached to it a gas delivery pipe, fuel gas and air being combined in the mixer to provide mixed gas and air. A venturi is secured at its inlet end to the mixer to receive the flow of gas and air, the venturi serving to draw air into the mixer. A burner nozzle is affixed to the venturi outlet end and the burner nozzle and extends within the fire tube. A perforated tube surrounds the mixer/venturi and at least a portion of the burner nozzle. A sound absorbing flame cell housing surrounds the perforated tube. A flame arrestor closes an air inlet opening in the flame cell housing air and serves to permit air to pass into the flame cell housing but prohibits the passage of flame therethrough so that flame is confined within the interior of the flame cell housing.

Abstract: This invention concerns a combustible gas atmospheric burner of the so-called "small-ramp type", comprising at least a body (1) consisting of two half-shells in a vertical plane of symmetry, configured in the lower part as a venturi tube (4), wherein the mixture of combustible gas and air is introduce by way of a nozzle (18). In its upper part it has a head made of high-temperature resisting material where the combustion takes place. The upper part of the burner body has portions of different cross-section so that the mixture exits from the said head in such a manner that its output is essentially uniform and of a laminar nature along the entire longitudinal dimension, which gives rise to a reduction in the noise emitted by the burner, as compared with similar arrangements of a known type.

Abstract: An apparatus and method of operation designed to reduce undesirably high pressure oscillations in lean premix combustion systems burning hydrocarbon fuels are provided. Natural combustion and nozzle acoustics are employed to generate multiple fuel pockets which, when burned in the combustor, counteract the oscillations caused by variations in heat release in the combustor. A hybrid of active and passive control techniques, the apparatus and method eliminate combustion oscillations over a wide operating range, without the use of moving parts or electronics.

Abstract: The periodic equivalence ratio modulation (PERM) method and apparatus significantly reduces and/or eliminates unstable conditions within a combustion chamber. The method involves modulating the equivalence ratio for the combustion device, such that the combustion device periodically operates outside of an identified unstable oscillation region. The equivalence ratio is modulated between preselected reference points, according to the shape of the oscillation region and operating parameters of the system. Preferably, the equivalence ratio is modulated from a first stable condition to a second stable condition, and, alternatively, the equivalence ratio is modulated from a stable condition to an unstable condition. The method is further applicable to multi-nozzle combustor designs, whereby individual nozzles are alternately modulated from stable to unstable conditions.

Abstract: A method and a device for burning fuel with air in a combustion chamber. The air is fed to the combustion chamber through at least one air inlet and the fuel is fed to the combustion chamber through a plurality of burners. Each burner has an associated delay time corresponding to a period of time after which an acoustic impulse in the combustion chamber causes a thermal impulse during combustion of the fuel fed through the burner. The feeding of the fuel through the burner is controlled in such a way that the delay times of the burners are substantially different from one another. The invention can be used on a combustion chamber of a gas turbine.

Abstract: An immersion tube burner having stable ignition and flame over a wide range of firing rates. The burner includes a restriction orifice located between the fan and the burner nozzle for minimizing pulsations of air pressure fluctuations between the fan and nozzle. The orifice is sized so that the air velocity is greater through the orifice than at the nozzle so that any such pulsations are directed downstream of the nozzle rather than upstream, where they can affect the flame. The burner includes a burner nozzle having a cone shaped mixing plate. The angled shape of the plate re-circulates hot gases towards the base of the flame to thereby ensure more consistent ignition and combustion. The mixing plate further has holes arranged in primary and secondary zones. The holes of the primary zone are located within approximately five times the diameter of the fuel outlet ports so that the fuel exiting such ports has sufficient velocity to optimize mixing.

Abstract: A vibration damper 38 for a fuel nozzle 24 having a central axis about which are disposed an inner 34 and outer 36 concentric fuel tubes. The damper includes a sleeve 40 and at least two legs 42, each leg having a radial portion extending from the sleeve and a resilient, longitudinally extending portion 46. The sleeve engages the inner tube while the longitudinally extending portions of the legs bear against the inner surface 37 of the outer tube to dampen vibrations between the concentric tubes. Besides damping objectionable vibratory forces experienced by the fuel tubes in the fuel nozzle, the present invention offers minimal fuel flow blockage in the concentric fuel tubes.

Abstract: An inshot burner (10) includes an axially elongated tubular nozzle (40) having a flared inlet end (42), a cylindrical outlet end (44) and a venturi section (46) therebetween. A burner head insert (20) is disposed within the cylindrical outlet end 44. The burner head insert (20) has an axially elongated annular body (22) having an axially extending inner flow passage (25) passing therethrough and a plurality of circumferentially spaced, axially extending splines (30) radiating outwardly therefrom toward the surrounding wall of the outlet end (44) of the burner tube. A plurality of second flow passages (35) are defined between the plurality of splines (30). Each of the axially extending splines (30) has a cross width which enlarges in the axial direction from the inlet end of the burner head insert to the outlet end of the burner head insert.

Abstract: Required blower power in an induced draft combustion system is reduced by recovering pressure from dynamic energy of flow of combustion products. To this end, the outlet duct is diverged gradually, such as an included angle of less than fifteen degrees, and preferably at an angle of substantially seven degrees. Divergence of the outlet duct may be expressed in polar coordinates having a polar axis, overlapping radius vectors and a variable polar angle of such overlapping radius vectors relative to the polar axis. A difference between such overlapping radius vectors is increased in a direction of flow of the combustion products and the outlet duct is structured with cross-sections increasing incrementally in terms of the increasing difference between the overlapping radius vectors. Condensate may be drained from a combustion product by providing the duct with a lateral offset having a bottom extending at an angle to the earth's field of gravity.

Abstract: A low NOx combustor and method improve dynamic stability of a combustion flame fed by a fuel and air mixture. The combustor includes a chamber having a dome at one end thereof to which are joined a plurality of premixers. Each premixer includes a duct with a swirler therein for swirling air, and a plurality of fuel injectors for injecting fuel into the swirled air for flow into the combustion chamber to generate a combustion flame therein. The fuel injectors are axially staged at different axial distances from the dome to uncouple the fuel from combustion to reduce dynamic pressure amplitude of the combustion flame.

Abstract: An apparatus for reducing the resonant type noise generated in a combustion driven heating apparatus. A dissipative device is disposed within a hot gas passageway to absorb and attenuate acoustic wave energy and thereby reducing the resonant noise level of the heating apparatus.

Abstract: A method of reducing pressure fluctuations in the combustor of a gas turbine engine resulting from the combustion of fuel and air therein comprises combusting a fuel/air mixture in a combustor downstream of the exit plane of a fuel nozzle assembly such that such recirculation zones generated by the fuel nozzle assembly are in spaced relation to the exit plane and the combustion products are isolated from the fuel and air in the mixing zone at all operating conditions of the engine.

Abstract: A multiple inshot-type gas burner structure is formed from a pair of facing, intersecured stamper sheet metal plates. A spaced plurality of parallel, rectangularly cross-sectioned burner bodies are defined by facing triangular indentation pairs in the plates and have, at front outlet end portions thereof, side indentations which serve to mix air and gaseous fuel received at rear end portions of the burner bodies, and to divert a portion of the fuel/air mixture into crossover channels intercommunicating front interior portions of the burner bodies. The crossover channels have central arcuate closed portions that cooperate with progressively sized standoff dimples extending between opposite wall portions of the channels to provide an even crossover flame pattern along the outlet slot section of each channel.

Abstract: The invention is intended to suppress oscillatory combustion of a combustion apparatus. In the invention, acoustic closed ends are provided at an inlet side and an outlet side of the burner port unit, and the combustion apparatus is constituted so that the flame may be positioned between these closed ends, and a buffer chamber is provided at the inlet side. Thus, when the inlet side and outlet side of the burner port unit of the combustion apparatus are formed as acoustic closed ends, oscillatory combustion occurs easily. At this time, when the intake tube communicates at the upstream side of the inlet side closed end, and an exhaust tube communicates at the downstream side of the outlet side closed end, if the length of the intake tube and exhaust tube is changed, the air ratio and combustion amount for generating oscillatory combustion remain constant, and the oscillation frequency and oscillation pressure remain constant.

Abstract: Combustion oscillation control in combustion systems using hydrocarbon fuels is provided by acoustically tuning a fuel-delivery line to a desired phase of the combustion oscillations for providing a pulse of a fuel-rich region at the oscillating flame front at each time when the oscillation produced pressure in the combustion chamber is in a low pressure phase. The additional heat release produced by burning such fuel-rich regions during low combustion chamber pressure effectively attenuates the combustion oscillations to a selected value.

Abstract: The method consists of providing a portion of greater cross-section in the gas feed conduit between the electromagnetic valve and the diffuser in a gas appliance, preferably for cooking or heating food.

Abstract: A gas burner assembly for connection to a gas source includes a burner body having a sidewall and a main gas conduit. The burner body further includes a number of primary burner ports disposed within the sidewall, each for supporting a respective main flame, and a simmer flame port disposed within the sidewall adjacent to the primary burner ports for supporting a simmer flame. Additionally, a main fuel chamber is disposed within the burner body to provide fuel to the primary burner ports, and a stability chamber is disposed within the burner body to channel fuel to the simmer flame port. In one configuration, the stability chamber has one or more stability inlets proximate the burner throat which provide the stability chamber with fuel by utilizing the static pressure associated with each stability inlet. In another configuration, the stability chamber has a small feed hole located proximate the burner throat of the main gas conduit.

Abstract: A device for damping thermoacoustic pressure vibrations in a combustion chamber (1), in particular in the combustion chamber of a gas turbine, includes a pressure sensor (6) which is connected to the input of a regulating device (10), the regulating device (10) is connected at its output to a device for electrically controlling the flame in the combustion chamber (1). This device for electrically controlling the flame includes a voltage source (11) and an electrode (14). The electrode (14) is connected to a heat shield (12) which surrounds the outflow side of a burner (3) in an annular manner.

Abstract: A flare stack with increased flow velocity of gases. The flare stack includes a pipe having a flare tip. The flare tip has a top edge. A conical shield having an apical end and a base is secured to and spaced from the flare tip to allow gas to flow between the conical shield and the flare tip. The conical shield is open at the apical end adjacent the top edge of the flare tip. A source of forced gas, preferably air, provides a flow of gas between the conical shield and the flare tip. Preferably, the base of the conical shield is closed.

Abstract: A fuel fired burner is provided for receiving a premixture of fuel and air. A ceramic flame support extends across the burner chamber and has a plurality of elongate slots through which the fuel and air flows. Each slot has a narrow constant dimension portion that opens into a wider constant dimension portion. The outlet end of the latter portion opens into a short diverging outlet. The arrangement is such that when the burner is operating within a given heat output range, the burner flame can move between the upstream and downstream ends of the diverging outlet to seek stabilization as the heat output changes within that range, without retracting into the slot upstream of the outlet.

Abstract: An apparatus for suppressing or attenuating acoustic pressure oscillations in a gas turbine engine combustor, the apparatus having a quarter wave resonator with a cavity closed at a first end and open at a second end and a characteristic length that reflects waves 180 degrees out of phase with the incoming waves and a viscous damper at the open end of the cavity. At least one resonating tube with a closed end and an open end and a single cavity therebetween, a damping plate with a plurality of apertures therethrough disposed across the open end, and a means for mounting the tube on the engine so that the damping plate is essentially flush with the wall. The apertures preferably have a total open area that is about 8% of an inclusive area of the open end and the tube may be cylindrical and the apertures circular.