Abstract:
A burner for a gas turbine, having a burner lance and/or burner hub, a burner passage which at least partially surrounds the burner lance and/or burner hub, and a fuel supply arrangement having at least one fuel nozzle and at least one fuel channel. The burner allows pollutant emissions to be reduced and offers a high degree of operational safety. The fuel supply arrangement has a fluidic oscillator that has an interaction chamber, the interaction chamber having at least one inlet and, lying opposite, one outlet region that has at least one outlet channel, one end of at least one feedback line terminating into the interaction chamber in the region of the inlet, the other end thereof terminating into the outlet region or into an outlet channel, and each end of the feedback line being sealed off from the interaction chamber by a flexible membrane.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is the US National Stage of International Application No. PCT/EP2015/070463 filed Sep. 8, 2015, and claims the benefit thereof. The International Application claims the benefit of German Application No. DE 102014218285.9 filed Sep. 12, 2014. All of the applications are incorporated by reference herein in their entirety. 
     
    
     FIELD OF INVENTION 
       [0002]    The invention relates to a burner for a gas turbine, having at least one burner lance and/or burner hub, and at least one burner passage that at least portionally surrounds the burner lance and/or burner hub. The burner also comprises a fuel supply arrangement, having at least one fuel nozzle and at least one fuel channel. 
       BACKGROUND OF INVENTION 
       [0003]    The burner serves to introduce fuel into a combustion chamber of the gas turbine. The fuel may be introduced into the combustion chamber directly in the outlet region of the burner, in order to generate a diffusion flame, for example in that the fuel is introduced into the combustion chamber or injected into the air stream adjacently to an air stream flowing out of a burner passage of the burner. Alternatively or additionally, the burner may introduce premixed fuel into the combustion chamber, in that the fuel is injected into a burner passage realized as a premix passage (by means of fuel nozzles that lead into the premix passage), and mixed in the premix passage with an air stream flowing through the premix passage. After emerging from the burner, the fuel/air mixture emerging from the premix passage is burned in the combustion chamber, rendering possible combustion that is particularly low in pollutants. Such premix flames, however, have a tendency toward combustion instabilities, for which reason such burners comprise, for example, pilot burners or further fuel passages for the purpose of stabilization. 
         [0004]    For the purpose of supplying the burner with a type of fuel, or generally a plurality of fuel types, the burner comprises a fuel supply system. The fuel supply system comprises a fuel supply arrangement, having at least one fuel channel, via which the fuel nozzles of the burner are supplied with fuel. The fuel nozzle may be, for example, a pressure-swirl nozzle. However, it may also be, for example, a burner passage outlet. 
         [0005]    The burner of the generic type comprises at least one burner lance and/or one burner hub. 
         [0006]    The burner lance may be, for example, a central lance of a pilot burner or cone burner having nozzles for diffusion operation. The burner lance may also be disposed centrally in a premix passage, or project into the latter from upstream. The burner lance may serve to guide the flow, or additionally comprise fuel nozzles that inject fuel into the premix passage. The nozzles of the burner lance may be supplied with fuel via at least one fuel channel of the fuel supply arrangement that extends in the burner lance. A fuel injector—for example in the form of a swirl generator comprising swirl blades—that is disposed around the lance may be disposed on the burner lance, which fuel injector likewise comprises fuel nozzles that lead into the premix passage. In this case, the fuel supply arrangement may extend along the burner lance, as far as the nozzles of the fuel injector. 
         [0007]    The burner hub denotes a component that radially inwardly delimits a burner passage, and in which there extends/extend at least one fuel channel of the fuel supply arrangement that supplies fuel to fuel nozzles disposed on the hub, and/or supply channels, which extend as far as fuel nozzles disposed in the burner passage. The burner hub may be disposed between the burner passage and a fuel supply unit that is disposed radially further inward, such that the burner hub at least portionally surrounds the supply unit that is disposed radially further inward. In order to reduce pollutant emissions during operation of the burner, it is sought to mix the injected fuel as finely and homogeneously as possible with the air flowing past. For example, pressure-swirl nozzles are used for this purpose in the prior art. 
       SUMMARY OF INVENTION 
       [0008]    The invention is based on the object of specifying a burner, of the type stated at the outset, and a gas turbine having at least one such burner, by means of which it is made possible to reduce emissions of pollutants, and by which improved operating reliability is additionally ensured. 
         [0009]    The object is achieved, according to the invention, in the case of a burner of the type stated at the outset, in that the fuel supply arrangement comprises at least one fluidic oscillator that has an interaction chamber, wherein the interaction chamber has at least one inlet for the intake of fuel and, located opposite, an outlet region, having at least one outlet channel for the outlet of fuel, wherein one end of at least one feedback line leads into the interaction chamber, in the region of the inlet, and the other end thereof leads into the outlet region or into an outlet channel, wherein the two ends of the feedback line are each sealed off from the interaction chamber by a flexible membrane. 
         [0010]    It is thus proposed, according to the invention, to integrate at least one fluidic oscillator into the fuel supply arrangement. In other words, at least one fuel nozzle is fluidically connected to an outlet channel of the fluidic oscillator, the inlet of the fluidic oscillator being fluidically connected to a fuel channel of the fuel supply arrangement. A fluctuation of the fuel supply of the fuel nozzle connected to the fluidic oscillator is thus effected, as a result of which stronger turbulences occur, between fuel emerging from the fuel nozzle and combustion air flowing past. This promotes better mixing. Emissions of pollutants are thereby reduced. 
         [0011]    Fluidic oscillators have long been known as fluidic control elements that do not require expensive valves. For example, they are used to supply air into the boundary layer of airfoils, in order to avoid separation of the boundary layer. 
         [0012]    Differing types of fluidic oscillator are known, which differ in their structure. Common to all of these types is that they have an interaction chamber that is entered, through an inlet, by a pressurized jet of fluid. The jet is applied periodically to differing side walls, or side-wall regions, of the interaction chamber, such that one may refer to an interaction of the jet with the side walls of the chamber, an oscillation of the jet being stimulated, such that the jet flows through the chamber periodically on differing paths and consequently, in the outlet region, leaves the interaction chamber periodically by differing outlets, or leaves a central outlet of the interaction chamber periodically in differing directions. The jet is thus periodically applied to, and comes away from, at least two opposing side-wall regions, this being caused by delaying of the flow. 
         [0013]    The periodic application of the jet to the side walls/side-wall regions may additionally be stabilized, in that the pressure of the outlet respectively receiving the jet is fed back to the inlet region by means of comparatively thin feedback lines, such that the jet obtains an impulse that presses it away from the side wall/side-wall region to which it is just then being applied. However, the feedback is not absolutely necessary for the oscillation of the jet. 
         [0014]    The functioning of fluidic oscillators is of the prior art, such that the fluidic oscillators are explained only briefly here. 
         [0015]    In the case of the present invention, it is proposed, according to the invention, to integrate at least one fluidic oscillator into a fuel supply arrangement of a burner for a gas turbine, such that, during operation, the at least one fuel nozzle outputs a pulsed jet of fuel, as a result of the outlet channel receiving fuel in a periodic manner. If the fluidic oscillator comprises a plurality of outlet channels (to which at least one fuel nozzle is connected downstream), the output of the fuel of the at least two fuel nozzles is effected with a time offset relative to each other. The frequency may be set by the geometry of the fluidic oscillator, in particular by the size of the chamber. 
         [0016]    The fuel nozzle connected to the outlet channel may be realized by the outlet channel itself, for example in that the outlet channel is realized as a full-jet nozzle. 
         [0017]    The fluidic oscillator according to the invention is particularly suited to receiving fuel. For this purpose, the two ends of the at least one feedback line are each sealed off against the interaction chamber by a flexible membrane. 
         [0018]    As already described further above, the feedback line serves to stabilize the oscillation, and functions by feeding a pressure in the outlet region back to the inlet region. In the prior art, these feedback lines are open toward the interaction chamber, such that a portion of the fluid flowing through the chamber fills the feedback line and is moved back and forth in the latter. The flexible membranes serve to transfer the pressure, without the fuel being able to enter the feedback line. According to the invention, the function of transferring the pressure is assumed by the air enclosed, between the membranes, in the feedback line, or by a specially filled fluid or gel. 
         [0019]    As a result, there is no region that forms in the feedback line in which fuel remains over a prolonged period and, in the case of oil as a fuel, becomes carbonized, which would cause choking of the feedback lines. This increases the operational reliability of the burner realized according to the invention. 
         [0020]    The flexible membrane is composed of a material that is resistant to the fuel. The membrane may be fastened in the end region of the feedback line, in the latter. However, it could also be fastened, for example, in the region of the mouth of the feedback line, on the inside of the interaction chamber, and in this case cover the mouth of the feedback line. Insofar as the feedback line leads into the outlet channel, the membrane could be fastened, analogously, to the inside of the outlet channel, and in this case cover the mouth of the feedback line. 
         [0021]    Advantageous designs of the invention are specified in the following description and the dependent claims, the features of which may be applied individually and in any combination with one another. 
         [0022]    It may be provided, advantageously, that the membrane is composed of a temperature-resistant high-grade steel or of a nickel-based material. 
         [0023]    This material is flexible, withstands the temperatures in the region of the fuel lines of gas turbine burners, and is corrosion-resistant with respect to fuel. The nickel-based material may also be referred to as a material based on nickel. 
         [0024]    Advantageously, it may further be provided that the feedback line is filled with a fluid or gel for the purpose of transmitting a pressure. 
         [0025]    The fluid may be an inert gas that, in the case of a failure of the membrane, behaves in a non-problematic manner when in contact with fuel. The gel may be, for example, an aerogel that is particularly resistant to heat. 
         [0026]    It may also be considered to be advantageous that at least one outlet channel of the interaction chamber is realized as a fuel nozzle in the form of a full-jet nozzle. 
         [0027]    This design has a simple structure and reduces the production costs. 
         [0028]    Advantageously, for the purpose of stimulating the oscillation, the interaction chamber comprises at least two oppositely disposed side-wall regions, which diverge from each other in the manner of a diffusor, at least in the inlet region of the interaction chamber, in the direction of the outlet region. 
         [0029]    The design of the invention relates to a fluidic oscillator that, owing to the wall regions diverging in the direction of the outlet, at least in the inlet region, stimulates an incoming jet to oscillates. Within the scope of this application, the term side-wall region may also be referred to as a side wall. 
         [0030]    In the case of the walls diverging in the manner of a diffusor in the inlet region, the jet entering under pressure is automatically applied periodically to differing side walls, and comes back away from the latter. The opening angle of the walls is suitably selected in this case. It may be selected, for example, so as to be greater than 7.5 degrees. Suitable opening angles are known from the prior art. 
         [0031]    The chamber may be realized, for example, in the form of a cone, having the outlets in the base area. The side walls/side-wall regions may extend, for example, in a curved course from the inlet region to the opposite outlet region, and the chamber may be round in cross-section. In this case, it is essential only that, owing to the side walls in the inlet region diverging in the direction of the outlet, the jet is stimulated to effect an oscillation in which it exits the chamber in a periodically alternating manner through differing outlets. 
         [0032]    An advantageous design of the invention may provide that the two side-wall regions diverge in such a manner that at least an angle of 7.5 degrees is realized between an inflow direction and the side-wall region. 
         [0033]    It may also be considered as advantageous that the two opposing side-wall regions extend in a curved shape from the inlet region to the outlet region. 
         [0034]    Further, it may be provided, advantageously, that the interaction chamber is realized so as to be substantially rotationally symmetrical, and the rotation axis goes through the inlet and the opposite outlet region, wherein the interaction chamber widens in the manner of a diffusor, at least in the inlet region, in the direction of the outlet. 
         [0035]    The inlet in this case is disposed on one side of the chamber, and the outlet region on the opposite side of the interaction chamber. 
         [0036]    It is a further object of the invention to specify a combustion chamber having at least one burner, and a gas turbine having at least one such combustion chamber, by means of which it is made possible to reduce emissions of pollutants during operation, and by which improved operating reliability is additionally ensured. 
         [0037]    For this purpose, the combustion chamber comprises at least one burner realized as claimed, and the gas turbine comprises at least one combustion chamber as claimed. 
         [0038]    The combustion chamber may be, for example, an annular combustion chamber, disposed at the top end of which there are one or more full-perimeter rows of burners. At least one of the burners may be realized as claimed. The combustion chamber may also be realized, for example, as a pipe combustion chamber or silo combustion chamber. At its top end, the combustion chamber may comprise a burner arrangement that has main burners disposed in the form of a circle. There may be one or more circles of disposed main burners. There may be a central pilot burner disposed in the middle. Each burner, or only one burner, or individual burners may be realized as claimed. 
         [0039]    The gas turbine may be a turbomachine having a plurality of combustion chambers—for example annular combustion chambers—the combustion chambers being disposed in succession in the direction of flow. The gas turbine may also comprise a circular arrangement of combustion chambers—for example pipe combustion chambers—the outlets of which are disposed in a ring-segment form on a common annular turbine inlet. 
         [0040]    The invention also relates to a fluidic oscillator having an interaction chamber, wherein the interaction chamber has at least one inlet for the intake of a fluid and, located opposite, an outlet region, having at least one outlet channel for the outlet of the fluid, wherein, for the purpose of stabilizing an oscillation of the fluid jet that can be stimulated by the interaction chamber, one end of at least one feedback line leads into the interaction chamber, in the region of the inlet, and the other end thereof leads into the outlet region or into an outlet channel. 
         [0041]    It is a further object of the invention to specify a fluidic oscillator of the above-mentioned type that is particularly suitable for operation with fuel. 
         [0042]    For this purpose, the ends of the feedback line are each sealed off from the interaction chamber by a flexible membrane. 
         [0043]    In the prior art, these feedback lines are open toward the interaction chamber, such that a portion of the fluid flowing through the chamber fills the feedback line and is moved back and forth in the latter. 
         [0044]    The flexible membranes serve to transfer the pressure, without the fuel being able to enter the feedback line. According to the invention, the function of transferring the pressure is assumed by the air enclosed, between the membranes, in the feedback line, or by a specially filled fluid or gel. 
         [0045]    As a result, there is no regions that form in the feedback line in which fuel remains over a prolonged period and, in the case of oil as a fuel, becomes carbonized, which would cause choking of the feedback lines. Consequently, the fluidic oscillator according to the invention is suitable for integration into a fuel supply arrangement, whereby it increases the operational reliability of the burner. 
         [0046]    The flexible membrane is composed of a material that is resistant to fuel. The membrane may be fastened in the end region of the feedback line, in the latter. However, it could also be fastened, for example, in the region of the mouth of the feedback line, on the inside of the interaction chamber, and in this case cover the mouth of the feedback line. Insofar as the feedback line leads into the outlet channel, the membrane could be fastened, analogously, to the inside of the outlet channel, and in this case cover the mouth of the feedback line. 
         [0047]    It may also be provided advantageously, that the membrane is composed of a temperature-resistant high-grade steel or of a nickel-based material. 
         [0048]    It may also be considered as advantageous that the feedback line is filled with a fluid or gel for the purpose of transmitting a pressure. 
         [0049]    An advantageous design of the invention may provide that, for the purpose of stimulating the oscillation, the interaction chamber comprises at least two oppositely disposed side-wall regions, which diverge from each other in the manner of a diffusor, at least in the inlet region of the interaction chamber, in the direction of the outlet region. 
         [0050]    At least one outlet channel of the fluidic oscillator may be realized as a fuel nozzle in the form of a full-jet nozzle. 
         [0051]    Further expedient designs and advantages are provided by the description of exemplary embodiments of the invention, with reference to the figure of the drawing, wherein components that have the same function are denoted by the same references. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0052]    There are shown in 
           [0053]      FIG. 1  a schematic representation of a gas turbine of the prior art, in a longitudinal section, 
           [0054]      FIG. 2  a schematic representation of a first type of a fluidic oscillator according to the prior art, in a longitudinal section, 
           [0055]      FIG. 3  a schematic representation of a burner according to the prior art, in a longitudinal section, 
           [0056]      FIG. 4  a schematic representation of a combustion chamber according to the prior art, in a longitudinal section, 
           [0057]      FIG. 5  a schematic representation of a burner of the combustion chamber represented in  FIG. 4 , in a longitudinal section, 
           [0058]      FIG. 6  a schematic representation of a fluidic oscillator according to the invention, according to a first exemplary embodiment, in a longitudinal section, and 
           [0059]      FIG. 7  a schematic representation of a burner according to the invention, according to a second exemplary embodiment, in a longitudinal section. 
       
    
    
     DETAILED DESCRIPTION OF INVENTION 
       [0060]      FIG. 1  shows a sectional view of a gas turbine  1  according to the prior art, in a schematically simplified representation. In its interior, the gas turbine  1  has a rotor  3 , which is mounted so as to be rotatable about a rotation axis  2 , and which has a shaft  4 , which is also referred to as a turbine rotor. Along the rotor  3 , in succession, there is an intake housing  6 , a compressor  8 , a combustion system  9 , having one or more combustion chambers  10 , which each comprise a burner arrangement having burners  11 , a fuel supply system (not represented) for the burners, and a combustion chamber housing  12 , and a turbine  14  and an exhaust-gas housing  15 . The combustion chamber  10  may be, for example, an annular combustion chamber. However, the invention may also relate to gas turbines that are realized as a turbomachine having a plurality of annular combustion chambers. The invention may also relate to gas turbines having one or more pipe or silo combustion chambers. The pipe combustion chambers may be disposed, for example, in the form of a ring at the turbine inlet. 
         [0061]    The combustion system  9  represented in  FIG. 1  communicates with a, for example annular, hot-gas channel. There, a plurality of turbine stages connected in succession constitute the turbine  14 . Each turbine stage is constituted by blade rings. As viewed in the direction of flow of a working medium, in the hot channel a row of guide blades  17  is succeeded by a row of rotor blades  18 . The guide blades  17  in this case are fastened to an inner housing of a stator  19 , whereas the rotor blades  18  of a row are attached, for example by means of a turbine disc, to the rotor  3 . A generator (not represented), for example, is coupled to the rotor  3 . 
         [0062]    During operation of the gas turbine, air is sucked in through the intake housing  6  and compressed by the compressor  8 . The compressor air L″ provided at the turbine-side end of the compressor  8  is guided along a burner plenum  7  to the combustion system  9  where, in the region of the burner arrangement, it is routed into the burners  11  and in the latter is mixed with fuel and/or enriched with fuel in the outlet region of the burner  11 . Fuel supply systems in this case supply the burners with fuel. The mixture, or the compressor air and the fuel, is/are discharged from the burners  11  into the combustion chamber  11  and combusts/combust, forming a hot stream of working gas in a combustion zone within the combustion chamber housing  12  of the combustion chamber. From there, the stream of working gas flows along the hot-gas channel, past the guide blades  17  and the rotor blades  18 . At the rotor blades  18 , the stream of working gas expands in an impulse-transmitting manner, such that the rotor blades  18  drive the rotor  3 , and the latter drives the generator (not represented) coupled thereto. 
         [0063]      FIG. 2  shows a fluidic oscillator of a first type according to the prior art, in longitudinal section. 
         [0064]    The oscillator  24   a  comprises an interaction chamber  26 , having precisely one inlet  28  that has an inlet region  30 , and having an oppositely disposed outlet region  32  that has a first outlet channel  34  and a second outlet channel  36 . Disposed for each outlet channel there is a relatively thin feedback line  38  that connects the inlet region to the outlet region, one end of the feedback line leading into the outlet channel in the example represented. The side-wall regions  40  diverge in the direction of the outlet region  32 , such that the interaction chamber  26  is triangular in longitudinal section. The oscillator  24   a  is not of a rotationally symmetrical structure, but is of a constant longitudinal section perpendicularly in relation to the plane of the drawing. 
         [0065]    Shown schematically in  FIG. 3  is a burner  90  according to the prior art, in a longitudinal section. The burner  90  has a central burner axis  66 , and a burner passage  100  that at least portionally surrounds the burner axis  66 . The burner passage  100  is realized as premix passage  92  in the form of an annular space, and radially outwardly is delimited by a wall  70 , the burner passage  100  being delimited radially inwardly by a centrally disposed burner hub  94 . Disposed in the premix passage  92  is a diagonal grating  96  that imparts a swirl to the compressor air L″ flowing in the premix passage. The diagonal grating is composes of a number of fuel injectors  98 , which are disposed all around the hub and whose main bodies, disposed in the premix passage, impart a velocity component, going in the circumferential direction of the passage, to the compressor air L″ flowing past. Extending in the burner hub  94  there is a fuel supply arrangement  73 , which comprises the fuel nozzles  80 , the fuel channel  82  (which may be realized all the way round in the cone of the burner hub) and supply lines (not represented), the supply lines branching off from the fuel channel  82  and extending as far as the fuel nozzles  80 , for the purpose of supplying the fuel nozzles. 
         [0066]    Shown schematically in  FIG. 4  is a portion of a combustion chamber  10  of the prior art, having a burner arrangement  48  at a top end of the combustion chamber. The combustion chamber comprises a combustion-chamber wall, having a flame tube  50  that comprises a combustion zone, and having a transition piece  52  that adjoins the flame tube and extends as far as a turbine inlet of the gas turbine. For the purpose of damping thermoacoustic oscillations that occur during operation, resonators  54  are disposed, at the level of the flame, on the combustion chamber wall. The burner arrangement  48  comprises a central pilot burner  56 , having a central burner lance  58 , and having a burner passage  60  that is realized as a pilot-burner premix passage. The pilot burner  56  comprises a pilot cone  62  that widens conically in the direction of flow. Main burners  64  are disposed in the form of a circle around the central pilot burner. The main burners  64  each have a burner axis  66  and a burner passage  68  that is disposed coaxially in relation to the burner axis, the burner passage  68  being delimited radially outwardly by a wall  70 , and when in operation being able to have a through-flow of compressor air L″, and serving to mix fuel and air L″, there being disposed in the burner passage  68  a central burner lance  72  and a number of fuel injectors that extend from the burner lance in the direction of the wall  70  and that are fluidically connected to a fuel supply arrangement (not represented) extending, at least partially, in the burner lance  72 , and that have fuel nozzles. The fuel injectors are realized as swirl blades of a swirl generator  74 , fuel nozzles being disposed on the swirl blades. 
         [0067]    Shown schematically in  FIG. 5  is a main burner  64  of the burner arrangement of  FIG. 4 , in longitudinal section. The burner  64  has a central burner axis  66 , and a burner passage  68  disposed coaxially in relation to the burner axis  66 , the burner passage being delimited radially outwardly by a wall  70 , and when in operation being able to have a through-flow of compressor air L″, and serving to mix fuel and air L″. A central burner lance  72  and a number of fuel injectors  79  are disposed in the burner passage. The fuel injectors  79  each comprises a main body  71 , disposed in the premix passage, that is realized as swirl blades  76  of a swirl generator  74 . The fuel injectors  79  comprise fuel nozzles  80  that open into the burner passage  68 , at the surface of the swirl blades  76 . In order to be supplied with fuel, the fuel nozzles  80  are fluidically connected to a fuel supply arrangement  73 . The fuel supply arrangement  73  comprises a fuel channel  82 , extending in the burner lance, and fuel supply channels  78 , which extend into the swirl blades  76 , as far as the respective fuel nozzles  80 . 
         [0068]    Shown schematically in  FIG. 6  is a fluidic oscillator  25  according to the invention according to a first exemplary embodiment, in a longitudinal section. The fluidic oscillator  25  comprises an interaction chamber  26  that is realized so as to be rotationally symmetrical about a rotation axis  31 . The inlet  28 , with an inlet region  30 , is disposed at one end of the chamber, the outlet region  32 , with two outlet channels  34  and  36 , being disposed oppositely. The side-wall regions  27  extend from the inlet to the outlet region, diverging, at least in the inlet region  30 , in the direction of the outlet, advantageously at an angle α&gt;7.5 degrees. Provided for each outlet channel there is a feedback line  38   a,    38   b,  one end of each of which leads, in the region of the inlet  28 , into the interaction chamber, and the other end of which leads into the outlet region  32 , the two ends of the feedback line  38  each being sealed off from the interaction chamber by a respective flexible membrane  37 . 
         [0069]    A jet of fuel under pressure entering the interaction chamber  26  in the inflow direction  29  advantageously is applied to the side walls  27 , an oscillation of the jet being stimulated because of the divergence of the side-wall regions  27  in the inlet region  30 , such that the jet is periodically applied to differing side-wall regions and periodically applies fuel to the two outlet channels  34  and  36 . The feedback lines  38   a,    38   b  feed a pressure in the outlet region  32  back to the inlet region  30 , and thereby stabilize the oscillation. In order that no fuel gets into the feedback lines, the feedback lines are sealed at their ends by the flexible membranes  37 , which transmit a pressure to a fluid  35  or gel, which may be, for example, air or an inert gas, enclosed in each feedback line. When, during the oscillation, fuel is applied to the outlet channel  34 , the membrane  37  of the feedback channel  38   a  that is disposed in the outlet region is pressed into the line  38   a,  as represented, such that the membrane  37  at the other end of the feedback line  38   a,  in the inlet region  30 , is pressed out. At this time, substantially no pressure is applied to the two membranes  37  that seal off the opposite feedback line  38   b.  Owing to the membrane  37 , the fluidic oscillator  25  is suitable for having a through-flow of fuel and for stimulating oscillation of the fuel jet, a safety risk, from standing fuel in the feedback lines, being reliably avoided. 
         [0070]    A burner  84  according to the invention, according to a second exemplary embodiment of the invention, is shown schematically in  FIG. 7 , in longitudinal section. Unlike the burner  64  of the prior art represented in  FIG. 5 , the fuel supply arrangement  73  has at least one fluidic oscillator  85  having an interaction chamber  26 , an inlet  28  of the interaction chamber being connected to the fuel channel  82  of the fuel supply arrangement  73 . Opposite the inlet region  30 , the interaction chamber  26  has an outlet region  32  having two outlet channels  34  and  36 . A first outlet channel  34  extends as far as a first group of fuel nozzles  80   a  in a first fuel injector  79   a.  A second outlet channel  36  extends as far as a second group of fuel nozzles  80   b  in an oppositely disposed fuel injector  79   b,  the fluidic oscillator  85  comprising a feedback line  38   a,    38   b  for each outlet channel, one end of the feedback line  38   a,    38   b  leading into the respective outlet channel  34 ,  36  downstream from the fuel nozzles  80   a,    80   b  that the outlet channel comprises, and the other end leading into the inlet region  30  of the interaction chamber  26 . 
         [0071]    The pressure prevailing at the end of the outlet channel is fed back to the inlet region  30  of the interaction chamber by the feedback lines  38   a,    38   b.  The membranes  37  seal off the feedback lines against the fuel, a pressure loading the membranes being transmitted from one end to the other end of the feedback line by means of a fluid or gel enclosed in the feedback line.