EP3004743B1 - Burner for a gas turbine and method for reducing thermo-acoustic oscillations in a gas turbine - Google Patents

Description

The invention relates to a burner for a gas turbine, which is designed in particular for the combustion of low calorific fuel gas. The invention also relates to a method for reducing thermoacoustic oscillations in a gas turbine, wherein the burner is suitable for carrying out the method.

In a combustion chamber, there may be an interaction of acoustic vibrations (pressure fluctuations) and fluctuations in the heat release, which can swell each other. Such thermoacoustic oscillations, which occur in particular in the combustion chamber of a gas turbine, can lead to considerable damage to the components during operation of the gas turbine and force shutdown of the system.

The invention also relates to a method for reducing thermoacoustic oscillations in a gas turbine comprising at least one burner, in which a delay time profile of a fuel flow flowing in a first fuel passage of the burner is adapted to reduce the thermoacoustic oscillations.

To provide a fuel gas to be combusted in the combustion chamber of the gas turbine, the generic burner comprises at least the above-mentioned first fuel passage which can be acted upon with fuel gas and an air passage which can be acted upon by compressor air to provide the air required for combustion. The two passages each have a main outlet opening into the combustion chamber of the gas turbine. The fuel passage may be formed as Vormischpassage or diffusion passage. For this purpose, the fuel passage to at least one supply connected for the fuel gas. Preferably, the fuel passage for the provision of synthesis gas is formed - in particular in the form of a Ringraumpassage. The burner may include further passages. For example, to initiate with the burner a variety of different fuels for combustion in the combustion chamber. The individual passages can also be connected to a plurality of feed systems, depending on the operating state of the burner to pressurize the passages with different fuels or flushing fluids.

In order for such burners to safely assume operating conditions in which the fuel supply to the above-mentioned fuel passage is turned off (to apply another passage to another fuel), it is known in the art to provide such burners with purging air passages to provide flashback into the fuel passage to avoid. In the known burners, compressor air is introduced from the air passage into the fuel passage through these purge air channels when the fuel supply is cut off. Fuel gases entering the passage via the main outlet opening are flushed out of the passage by the compressor air in these known burners. This avoids a flashback in the burner.

The invention relates to a generic burner which comprises at least one connection channel arranged upstream of the main outlet openings and fluidically connecting the air passageway and the fuel passageway.

Burners are known from the prior art, which comprises a number of fuel nozzles, which open into the first fuel passage and are arranged offset in the flow direction to each other to broaden a delay time profile of flowing in a first fuel passage fuel gas stream. A burner having the features of the preamble of claim 1 and a method having the features of the preamble of claim 16 are known from WO 2009/068425 known.

The invention has for its object to provide a burner and a method of the type mentioned, with which the reduction of thermoacoustic oscillations in a combustion chamber of a gas turbine is made possible in an alternative manner. The burner is designed such that in at least a first operating state of the burner when acted upon air passage with compressor air and acted upon fuel passage with fuel gas part of the fuel gas flowing in the fuel passage via at least one connecting channel flows into the air passage. The branched-off part of the fuel stream can be introduced into the interior of the combustion chamber for combustion through the main exit opening of the air passage. A part of the fuel gas remaining in the fuel passage can be introduced into the interior of the combustion chamber through the main exit opening of the fuel passage. The amount and radial fuel distribution of the branched portion of the fuel stream is such that the feedback of the heat release variations with the pressure variations in the combustion chamber is reduced.

The invention is based on the recognition that the radial distribution of the fuel-in particular in the case of a synthesis gas air mixture-plays a decisive role for the acoustic stability of the burner. The burner according to the invention allows a better acoustic stability, so that an extended operating range of the burner is possible in terms of load and fuel quality.

In the combustor of the present invention, the radial fuel / air distribution of a fuel stream flowing in a fuel passage may be adjusted without substantially altering basic fuel design aerodynamic parameters such as swirl number, pressure drop, and major passage dimensions. The invention allows Also, with different fuel compositions to adapt the burner to the thermoacoustic behavior of the combustion chamber, without requiring an adjustment of the entire fuel passage would be required.

The burner is designed such that in at least a first operating state of the burner when acted upon air passage with compressor air and acted upon fuel passage with fuel gas applied to the junction of the fuel connecting channels static pressure from the side of the fuel passage is greater than from the side of the air passage. The burner is designed such that the fuel stream, after it already flows in the fuel passage, is split. There is thus a division of the fuel supply system, but the division / diversion takes place after introduction of the fuel into the fuel passage, but upstream of the main outlet.

According to the invention, the burner is designed such that the feedback of the heat release fluctuations with the pressure fluctuations in the combustion chamber is reduced by the division / diversion of the fuel flow flowing in the first fuel passage.

Due to the division and diversion of the fuel flow flowing in the first fuel passage, the flame front changes in front of the burner. This can be adjusted by means of the amount and the radial distribution of the branched portion of the fuel stream such that the feedback of the heat release fluctuations is reduced with the pressure fluctuations in the combustion chamber. In order to achieve a relevant change in the flame front, the radial fuel distribution of the branched portion of the fuel flow extends substantially the thickness of one between the two Emerging streams occurring shear layer out into the air passage.

The invention thus does not relate to a manipulation of the thickness of the shear layer between the compressor air flow leaving the air passage and the fuel flow leaving the main exit opening of the fuel passage. Rather, to reduce feedback of the heat release variations with the pressure variations in the combustion chamber, the invention proceeds in a different way in that the amount and radial fuel distribution of a branched portion of the fuel gas flowing in the fuel passage is such that change of the flame front (with a change the delay time profile of the fuel flow is accompanied) the reduction of a feedback of the heat release fluctuations with the pressure fluctuations in the combustion chamber is effected.

In order to realize the desired branching of the part of the fuel stream, the position of the connecting channels and their diameter can be selected correspondingly in the two passages. However, the invention assumes that the burner for producing suitable pressure conditions on the connecting channels comprises flow-guiding means in the fuel passage and / or adjusting element in the region of the connecting channels, which suitably determine the static pressure in the inlet region of the connecting channels. The flow-guiding means and / or adjusting elements can be changed or exchanged in order to adapt the division / branching off of the fuel flow, for example in their position or form. As a result, the position of the connection channels in the passages can be freely selected over a wide range. The connecting channels are arranged downstream of the feed lines used in the first operating state of air or supply of the fuel gas and upstream of the two main outlet openings of the two passages, so that fuel gas can be diverted into the air flow.

The main outlet opening may be formed, for example, as an annular opening at the outlet of the passage. According to a further embodiment, the main exit opening may consist of a multiplicity of holes in a metal sheet (covering the exit opening of the burner passage). The main exit opening is arranged at the combustion chamber end of the passage.

The connection channels are arranged along a wall defining the fuel passage, for example in a circumferential sequence, so that their inlet openings are arranged in a circumferential row in the fuel passage and the channels extend through the wall to the air passage. Preferably, the pressure conditions in the burner can be designed such that the connecting channels also counteract a flashback in the burner when the supply of fuel to the first fuel passage is switched off.

Advantageous embodiments of the invention are set forth in the following description and the dependent claims, the features of which can be used individually and in any combination with each other.

Advantageously, it can be provided that the burner is designed such that the caused by the branch common delay profile of the remaining part and the branched portion of the fuel flow is adapted to a thermoacoustic behavior of the combustion chamber, so that the feedback of the heat release fluctuations with the pressure fluctuations in the combustion chamber is reduced.

Due to the division and diversion of the fuel flow flowing in the first fuel passage, the flame front changes in front of the burner. It can thus set a different common delay profile of the diverted and the remaining part of the fuel flow. The delay time is the period of time that the fuel from the Outlet from the burner to the flame front needed. Since the fuel has different delay times in the fuel stream (depending on the exit location at the burner outlet and depending on the position of the flame in front of the exit location), a delay profile of the fuel flow occurs in the respective operating state. An undesirable feedback of heat release fluctuations and pressure fluctuations in the combustion chamber can be reduced by means of the division and diversion of the fuel flow, since depending on the amount and radial fuel profile of the branched portion of the fuel flow, the common delay profile can change. If, for example, the proportion of the profile whose delay time substantially corresponds to the frequency of a preferred combustion chamber pressure fluctuation is reduced, this reduces a feedback of heat release fluctuations and pressure fluctuations in the combustion chamber.

The inventive design of the burner is thus such that at least in the first operating state, a dampening or not aufschaukelnd acting for the thermoacoustic behavior of the combustion chamber delay profile of the fuel flow is effected.

With thermoacoustic vibration behavior is meant that gas turbine combustors depending on the power range preferably at certain frequencies / frequency bands for rocking thermoacoustic oscillations tend (characteristic buzzing behavior). These frequencies are also referred to as preferential combustion chamber pressure fluctuations. If the delay profile of a burner is adjusted accordingly-in particular widened-this can counteract a rocking of the oscillations in the region of at least one such characteristic hum / frequency band. In this sense, the delay profile can be adapted to the thermoacoustic behavior of the combustion chamber or tune it and counteract a buildup of thermoacoustic oscillations in the combustion chamber. The delay profile can be, for example, by means of the proportion and / or the penetration depth (radial profile) and / or the distribution of the branched fuel flow to the individual connection channels influence. With regard to the first fuel passage, the burner comprises a correspondingly formed branch which, at least in the first operating state, effects a delay profile of the fuel flow that damps the thermoacoustic behavior of the combustion chamber.

An advantageous embodiment of the invention can provide that the first fuel passage is designed at least for an application of low-calorie fuel gas.

Under a low calorific fuel - in contrast to a standard fuel - in particular a fuel with a calorific value of below 20 MJ / kg, preferably below 10 MJ / kg to understand. This could for example be a very low calorific natural gas or a so-called synthesis gas. Synthesis gas usually has major proportions of CO, H ₂ and optionally minor proportions such as N ₂ and Co ₂ and water vapor. Standard fuel is usually a normal and / or high calorific fuel whose calorific value is well above 30 MJ / kg. For example, normal natural gas typically has a calorific value of between 40 to 50 MJ / kg. The combustible component of standard fuels for gas turbines consists essentially of hydrocarbons. By contrast, the combustible constituents of the synthesis gas are essentially CO and H2. Due to the low calorific value consequently high volume flows of fuel gas must be supplied through the burner of the combustion chamber. This has the consequence that one or more separate fuel passages must be made available for the combustion of low calorific fuels - such as synthesis gas. Because of the high reactivity of synthesis gases compared to conventional fuels such as natural gas and oil, there is a significantly higher risk of flashback.

The present invention can be applied to this fuel passage for low calorific fuels in a particularly advantageous manner.

The fuel passage may be configured for a diffusion operation or a premix operation for introducing the low-calorie fuel gas into the combustion chamber. In the premixing operation, the low-calorie fuel gas-which may be synthesis gas in particular-is premixed with air to form a low-calorie fuel-air mixture and conversion of the low-calorie fuel-air mixture in the fuel passage is avoided, so that the fuel-air Mixture is first converted into a hot gas in the combustion chamber. The invention preferably starts from a synthesis gas passage for a diffusion operation in which a swirl is imparted to the fuel flow by means of swirl generators by means of blades. The synthesis gas passage is preferably designed as a ring chamber passage and may be formed tapering downstream tapered.

Preferably, the burner can be arranged essentially rotationally symmetrically about a longitudinal axis, so that a main flow direction of the fluid flowing in the passages of the burner essentially points in the direction of the longitudinal axis (in particular in the passages arranged radially closer to the longitudinal axis) or at least one component in the direction of Longitudinal axis has (in particular in the radially outer passages, which can run upstream substantially first diagonal to the longitudinal axis and downstream approach a parallel course of the longitudinal axis). The air passage and the fuel passage may be arranged coaxially with one another at least in sections, in particular the air passage coaxially around the fuel passage.

It can also be advantageously provided that the main outlet openings of the air passage and the fuel passage are arranged such that the coaxially surrounding passage with respect to a plane perpendicular to the longitudinal axis projection plane is arranged around the other main outlet opening around.

This produces coaxially arranged flames from a common fuel stream with an adjusted delay profile.

A particularly simple construction results when the air passage and the fuel passage adjoin one another at least in sections along a substantially cylinder and / or truncated cone-shaped wall, wherein the connection channels are formed as holes in the wall.

According to the inventive Ausgesltaltung at least one adjusting element is arranged in the region of the connecting channels, so that the proportion and / or the radial inflow and / or the distribution on the connecting channels of the fuel passage from the fuel passage into the air passage branched fuel gas by means of at least one adjustment and / or is adjustable.

The adjusting element can influence the static pressure in the region of the inlet opening of at least one connecting channel, so that a suitable position of the inlet opening is not fixed exclusively by the pressure conditions which occur in the fuel passage in the first operating state. In addition, the adjustment can be easily adapted to a desired delay profile (for example, by exchange or change its shape) as the location or size of the at least one connecting channel. According to a particularly preferred embodiment of the adjusting element downstream of at least one fuel passage side inlet opening of a connecting channel, a flow guiding means is arranged in the fuel gas passage, which increases the static pressure in the region of the inlet openings of the connecting channel when the fuel passage with fuel gas.

It may also be considered advantageous for the flow-guiding means to comprise a substantially annularly formed plate, wherein the plate is arranged circumferentially on an inner side of a wall bounding the fuel passage. (The term "sheet" refers to the shape but is not meant to be limiting in material choice within the scope of this invention).

This embodiment of the Strömungsleitmittels has a particularly simple structure and thus low production costs.

In order to achieve a particularly strong increase in the pressure, the sheet can inclined against a main flow direction in the fuel passage extend into the interior of the fuel passage. For example, it may project beyond at least a portion of the inlet openings of the connection channels.

In order to influence the flow path between the inlet openings of the connecting channels as little as possible, the substantially annular plate between the downstream of the inlet openings of the connecting channels areas each having a recess, so that the sheet, for example, downstream of the inlet openings comprises a triangular or trapezoidal pinnacle.

For example, it may be preferable for the adjustment element to comprise a number of flow-guiding means which are designed as triangular or trapezoidal sheets. The triangular sheets may be arranged on the inside of the fuel passage analogous to the above-mentioned substantially annular sheet. However, the individual sheets have the advantage that downstream of the regions between the inlet openings, no unfavorably increasing the pressure loss increasing areas of a Strömungsleitmittels are arranged. An alternative, advantageous embodiment of the Strömungsleitmittels may comprise at least one cap-shaped element having an input opening, which is arranged with the inlet opening in the direction of the inlet opening of a connecting channel downstream of the inlet opening on an inner side of the fuel passage defining wall.

Advantageously, the cap-shaped element may substantially have the shape of a quarter-hollow sphere. This can project beyond the inlet opening at least partially.

Furthermore, it may be advantageously provided that at least one adjusting element is tubular, wherein the tubular adjusting element is arranged in particular at least partially in each case one of the connecting channels.

According to a first embodiment of the embodiment of the invention, the at least one tubular adjusting elements may be partially inserted into a respective connecting channel and project into the air passage, so that the radial position of the junction of the diverted partial flow flowing through the respective connecting channel can be accurately positioned. Depending on the desired radial inflow profile, how far the tubular adjusting element protrudes into the air passage can also be chosen differently from a tubular adjusting element to a tubular adjusting element. According to a further embodiment of the embodiment of the invention, the at least one tubular adjusting element can for example be arranged completely in each case in a connecting channel. For example, to adjust the radial inflow profile of the branched fuel stream, the wall thicknesses of the at least one tubular adjusting element can be selected accordingly. According to a further embodiment of the invention, the at least one tubular adjusting element can be fastened in the extension of a connecting channel on the inside of the air passage. According to a further embodiment, the at least one tubular adjusting element additionally or alternatively to the mentioned embodiments protrude into the fuel passage and include, for example, at its projecting into the fuel passage end an inlet shell. The inlet shell may be formed, for example, analogous to the triangular plates or the quarter Holhkugel. The aforementioned embodiments of the tubular adjusting element can for example be combined with each other or used individually. If a plurality of such tubular adjustment elements are provided, they may all be of the same design or differ from one another, for example in accordance with the exemplary embodiments mentioned and their combinations, depending on the desired radial inflow profile of the branched fuel stream.

Another object of the invention is to provide a method of the type mentioned, with which the reduction of thermo-acoustic vibrations in a combustion chamber of a gas turbine is made possible in an alternative manner.

The object is achieved in a method of the type mentioned fact that for adjusting the delay time profile of a flowing fuel flow in a first fuel passage, a remaining portion of the fuel stream is introduced through at least one main exit opening of the first passage in the combustion chamber and a branched-off portion of the fuel stream downstream its introduction into the fuel passage and upstream of the main outlet opening via at least one connecting channel is introduced into at least a second passage, wherein the branched portion of the fuel stream is introduced separately from the remaining fuel flow into the combustion chamber, so that the partial streams after their exit from the burner with different delay times or Verzugszeitenprofilen be burned in the combustion chamber, wherein for adjusting the delay time profile of the proportion of the branched partial flow and / or its inflow and / or r its division is adjusted to the at least one connecting channel such that the feedback of the heat release fluctuations is reduced with the pressure fluctuations in the combustion chamber.

With regard to the design options and advantages of the method, reference is made to the above comments on the burner according to the invention.

Advantageously, it can further be provided that the remaining fuel flow and the branched off part of the fuel flow are introduced into the combustion chamber essentially coaxially with one another.

In order to adapt the thermoacoustic behavior of the combustion chamber comprising the burner, the proportion and / or the inflow profile and / or its division onto the at least one connecting channel of the branched off part of the fuel stream is set before the burner is put into operation and / or during the operation of the burner. According to the invention, the setting of the proportion and / or the penetration depth and / or the division takes place on the at least one connecting channel by adjusting at least one arranged in the fuel passage Strömungsleitmittels and / or arranged in the region of the connecting channels adjustment.

According to an advantageous embodiment of the invention, the adaptation of the at least one Strömungsleitmittels and / or adjusting element can be done by replacing and / or adjusting its shape and / or position.

Another object of the invention is to provide a combustion chamber with at least one burner and a gas turbine with at least one such combustion chamber, with which the suppression of thermoacoustic vibrations in one Combustion chamber of a gas turbine is made possible in an alternative manner.

The object is achieved in a combustion chamber of the type mentioned above in that the burner is designed according to one of claims 1 to 15.

The object is achieved in a gas turbine of the type mentioned above in that the combustion chamber is designed according to claim 16.

Further expedient refinements and advantages of the invention are the subject matter of the description of embodiments of the invention with reference to the figure of the drawing, wherein like reference numerals refer to like acting components.

Fig.1

schematisch einen Längsschnitt durch eine Gasturbine nach dem Stand der Technik, und

Fig.2

schematisch einen Längsschnitt durch einen erfindungsgemäßen Brenner gemäß einem ersten Ausführungsbeispiel,

Fig.3

schematisch einen Längsschnitt durch einen erfindungsgemäßen Brenner gemäß einem zweiten Ausführungsbeispiel, und

Fig.4

schematisch einen Längsschnitt durch einen erfindungsgemäßen Brenner gemäß einem dritten Ausführungsbeispiel.

It shows the

Fig.1

schematically a longitudinal section through a gas turbine according to the prior art, and

Fig.2

1 shows a schematic longitudinal section through a burner according to the invention according to a first exemplary embodiment,

Figure 3

schematically a longitudinal section through a burner according to the invention according to a second embodiment, and

Figure 4

schematically a longitudinal section through a burner according to the invention according to a third embodiment.

The FIG. 1 shows a schematic sectional view of a gas turbine 1 according to the prior art. The gas turbine 1 has inside a rotatably mounted about a rotation axis 2 rotor 3 with a shaft 4, which is also referred to as a turbine runner. Along the rotor 3 follow one another Intake housing 6, a compressor 8, a combustion system 9 with a number of combustion chambers 10, a turbine 14 and an exhaust housing 15. The combustion chambers 10 each include a burner assembly 11 and a housing 12, which is lined with a heat shield 20 for protection against hot gases.

The combustion system 9 communicates with an annular hot gas duct, for example. There, a plurality of successively connected turbine stages form the turbine 14. Each turbine stage is formed of blade rings. Viewed in the flow direction of a working medium follows in the hot runner formed by a number 17 vanes row formed from blades 18 row. The guide vanes 17 are fastened to an inner housing of a stator 19, whereas the moving blades 18 of a row are attached to the rotor 3, for example by means of a turbine disk. Coupled to the rotor 3 is, for example, a generator (not shown).

During operation of the gas turbine, air is sucked in and compressed by the compressor 8 through the intake housing 6. The compressed air provided at the turbine-side end of the compressor 8 is led to the combustion system 9 where it is mixed with a fuel in the area of the burner assembly 11. The mixture is then burned by means of the burner assembly 11 to form a working gas stream in the combustion system 9. From there, the working gas stream flows along the hot gas channel past the guide vanes 17 and the rotor blades 18. At the rotor blades 18, the working gas stream relaxes in a pulse-transmitting manner, so that the rotor blades 18 drive the rotor 3 and this drives the generator (not shown) coupled to it.

The FIG. 2 schematically shows a detail of a burner 24 according to the invention for a gas turbine according to a first embodiment in a longitudinal section.

The burner 24 comprises an air passage 26 which can be charged with compressor air and is designed as an annular channel. a fuel passage 28 configured for synthesis gas charging; and a secondary delivery unit 30 that may include a pilot burner (not explicitly shown) and other passages (not explicitly shown) for introducing a fluid. The burner has a substantially rotationally symmetrical structure about a longitudinal axis 32. Here, the air passage 26 coaxially includes the synthesis gas-designed fuel passage 28, which in turn coaxially surrounds the secondary feed unit 30. Both the secondary feed unit 30 and the two passages 26 and 28 each have a main outlet opening 36, 38, 40 opening into the combustion chamber 34.

In this case, the main outlet openings 36 are arranged around the main outlet opening 38 with respect to the projection plane 50 running perpendicular to the longitudinal axis 32.

Compressor air entering the air passage 26, the main flow direction of which is indicated by an arrow L "in the entry region, is swirled by a swirler 42 (Swirler) disposed in the air passage The blades of the swirler extend from a passage defining inner wall 44a to a passage-limiting outer wall 46, with the vanes annularly disposed about the circumference of the wall The air flow exits the air passage 26 through the main exit port 36. For introducing synthesis gas into the combustion chamber 34, a synthesis gas stream 48 (FIG. which may also be premixed with compressor air prior to entry into the illustrated portion of the fuel passage 28) .The feed line system is not shown in the figure because it is outside of the illustrated cutout also blades 52 of a swirl generator in the fuel passage 28 arranged. Downstream of the blades 52, the fuel passage 28 and the air passage 26 are fluidly connected to each other via connection channels 54. The connection channels 54 are in the illustrated embodiment, disposed in a region in which the air passage 26 and the fuel passage 28 along a substantially cylinder jacket wall 56 adjacent to each other, wherein the connecting channels 54 are formed as holes in the cylinder jacket-shaped wall 54.

The burner 24 is designed such that in at least a first operating state of the burner with acted upon air passage 26 with compressor air and acted upon fuel passage 28 with fuel gas part of the fuel gas flowing in the fuel passage via the connection channels 54 flows into the air passage 26 and through to its combustion the main outlet opening 36 of the air passage into the interior of the combustion chamber 34 can be introduced.

The embodiment of the branching is such that the common delay profile of the fuel flow prevents or reduces rocking of thermoacoustic oscillations occurring in the respective combustion chamber 34 of the gas turbine as a function of the power range at characteristic frequency bands, at least in one frequency band. Thus, feedback of heat release variations and pressure fluctuations in the combustion chamber is reduced.

The delay time profile is adapted by means of an adjusting element 60 to the thermoacoustic behavior of the combustion chamber 34. The adjusting element 60 in the first embodiment consists of a flow guide 62, which is arranged downstream of the fuel passage side inlet openings 64 of the connecting channels 54 in the fuel passage 28 and increases the static pressure in the region of the inlet openings 64 of the connecting channels 54 when the fuel passage 28 is exposed to fuel gas. The flow guide 62 has the shape of a substantially annular plate 66. This is circumferentially on the inside 68 of the fuel passage 28 bounding wall 56th disposed and extends against a main flow direction 70 in the fuel passage 28 inclined into the interior of the fuel passage. The sheet 66 protrudes while maintaining a distance over at least a portion of the inlet openings 64. Depending on the proximity, height and angle and shape of the sheet 66, the proportion and / or the radial inflow and / or the distribution on the individual connection channels of the fuel passage 28 set in the air passage 26 branched fuel gas by means of at least one adjusting element 60.

An adverse increase in the pressure loss in the passage due to the Strömungsleitmittels can be advantageously reduced for example by recesses (not shown) in the sheet 66, which are each arranged between the downstream of the inlet openings of the connecting channels areas.

To prevent a disadvantageous increase in the pressure loss, a segmentation of the sheet is even more advantageous. The adjusting element 60 may consist of a number of sheets, which are each arranged downstream of the inlet openings 64. These can, for example, as in FIG. 3 represented, the shape of triangular sheets 74 which are bent over the inlet openings. For the sake of clarity is in the FIG. 3 only a single such sheet 74 is shown.

According to a further embodiment, the in FIG. 4 1, the adjusting element 60 may consist of a series of cap-shaped elements 84, each comprising an inlet opening 86 and arranged with this in the direction of the inlet opening 64 of a connecting channel 54 downstream of the inlet opening 64 on an inner side 68 of a wall 56 delimiting the fuel passage 28 are and preferably at least partially project beyond the inlet opening 64. At the in FIG. 4 illustrated embodiment, the cap-shaped element 84 substantially the Shape of a quarter-hollow sphere on. In the FIG. 4 is also the sake of clarity, only such a quarter-hollow sphere shown.

The in the FIGS. 2 to 4 illustrated burner 24 according to the invention are suitable for carrying out the method according to the invention. Regarding FIG. 3 for adjusting the delay time profile of a fuel gas stream 78 flowing in a fuel passage 28, a remaining portion 80 of the fuel stream is introduced into the combustion chamber 34 through at least one main exit port 38 of the fuel passage 28. A diverted portion 82 of the fuel stream is introduced downstream of its introduction into the fuel passage and upstream of the main outlet openings 36 and 38, via the connecting channels 54 in the air passage 26. The branched-off part 82 of the fuel stream is introduced separately from the remaining fuel stream 80 into the combustion chamber 34, so that the partial streams are burnt after their exit from the burner 24 with different delay times or delay profiles in the combustion chamber 34, wherein the burner 24 is designed such that the common delay profile of the fuel streams 82 and 80 on the proportion of the branched partial stream 82 and / or its inflow and / or its distribution to the at least one connecting channel 54 is tuned to a thermoacoustic behavior of the combustion chamber 34, so that a feedback of heat release fluctuations and Pressure fluctuations in the combustion chamber is reduced.

Claims (18)

1. Burner (24) for a gas turbine (1), having at least one air passage (26) to which compressed air may be supplied and at least one fuel passage (28) to which at least one fuel gas may be supplied, the two passages (26, 28) each comprising a main outlet opening (36, 38) leading into the combustion chamber (34) of the gas turbine (1), the air passage (26) and the fuel passage (28) being connected fluidically together via at least one connection duct (54) arranged upstream of the main outlet openings (36, 38), whereby the burner (24) is configured such that, in at least one first operating state of the burner, when air passage (26) is supplied with compressed air and fuel passage (28) is supplied with fuel gas a portion (82) of the fuel gas flowing in the fuel passage flows via at least one connection duct (54) into the air passage (26) and, for combustion thereof, may be introduced through the main outlet opening (36) of the air passage into the interior of the combustion chamber (34) and a remaining portion (80) of the fuel gas may be introduced through the main outlet opening (38) of the fuel passage into the interior of the combustion chamber,
   characterized in that
   at least one adjusting element (60) is arranged in the region of the connection ducts (54), such that the fraction (82) and/or the radial inflow profile and/or the division over the connection ducts (54) of the fuel gas branched off from the fuel passage (28) into the air passage (26) is adjusted and/or adjustable by means of the at least one adjusting element (60), such that fluctuations in heat release are fed back to a lesser extent into the pressure fluctuations in the combustion chamber.
2. Burner (24) according to Claim 1,
   characterized in that the burner (24) is configured such that
   the common dwell time profile, brought about by the branching off, of the remaining portion (80) and of the branched-off portion (82) of the fuel stream is adapted to the thermoacoustic behavior of the combustion chamber (34), such that fluctuations in heat release are fed back to a lesser extent into the pressure fluctuations in the combustion chamber.
3. Burner (24) according to one of Claims 1 or 2,
   characterized in that
   the burner (24) is arranged substantially rotationally symmetrically about a longitudinal axis (32), such that a main direction of flow of the fluid flowing in the passages (26, 28) of the burner points in the direction of the longitudinal axis or has at least one component in the direction of the longitudinal axis (32), and the air passage (26) and the fuel passage (28) are arranged coaxially to one another at least in places.
4. Burner (24) according to one of the preceding claims,
   characterized in that
   the main outlet openings (36, 38) of the air passage and fuel passage are arranged such that the coaxially surrounding passage (26) is arranged around the other main outlet opening (38) relative to a projection plane (50) extending perpendicular to the longitudinal axis.
5. Burner (24) according to one of the preceding claims,
   characterized in that
   the air passage (26) and the fuel passage (28) adjoin one another at least in places along a wall (56) which substantially takes the form of a cylindrical casing and/or of a truncated cone-shaped casing, wherein the connection ducts (54) take the form of holes in the wall (56).
6. Burner (24) according to one of the preceding claims,
   characterized in that a flow guide means (62) is arranged in the fuel gas passage downstream of at least one fuel passageside inlet opening (64) of a connection duct (54), which flow guide means increases the static pressure in the region of the inlet openings (64) of the connection duct (54) when the fuel passage is supplied with fuel gas.
7. Burner (24) according to Claim 6,
   characterized in that
   the flow guide means (62) comprises a substantially annular metal plate (66), wherein the metal plate (66) is arranged circumferentially on an inside (68) of a wall (56) delimiting the fuel passage.
8. Burner (24) according to Claim 7,
   characterized in that
   the metal plate (66) extends into the interior of the fuel passage (28) at an angle contrary to a main direction of flow (70) in the fuel passage (28).
9. Burner (24) according to one of Claims 7 or 8,
   characterized in that
   the metal plate (66) in each case has a cut-out between the regions located downstream of the inlet openings (64) of the connection ducts (54).
10. Burner (24) according to one of Claims 6 to 9,
    characterized in that
    the adjusting element (60) comprises a number of flow guide means (62), which take the form of triangular or trapezoidal metal plates (74).
11. Burner according to Claim 6,
    characterized in that
    the flow guide means (62) comprises at least one cupped element (84) with an entry opening (86), which is arranged with the entry opening pointing towards the inlet opening (64) of a connection duct (54) downstream of the inlet opening (64) on an inside (68) of a wall (56) delimiting the fuel passage.
12. Burner according to Claim 11,
    characterized in that
    the cupped element (84) substantially takes the form of a hollow quarter-sphere.
13. Burner according to one of the preceding claims,
    characterized in that
    at least one adjusting element (60) is of tubular configuration, wherein the tubular adjusting element is in each case arranged in particular at least in part in one of the connection ducts.
14. Combustion chamber having at least one burner,
    characterized in that
    the burner (24) is configured according to one of Claims 1 to 13.
15. Gas turbine having at least one combustion chamber,
    characterized in that
    the combustion chamber (34) is configured according to Claim 14.
16. Method for reducing thermoacoustic oscillations in a gas turbine (1) comprising at least one burner (24), in which method, to reduce the thermoacoustic oscillations, a dwell time profile of a fuel stream (48, 78) flowing in a first fuel passage (28) of the burner is adapted to the thermoacoustic behavior of the combustion chamber, wherein, to adapt the dwell time profile, a remaining portion (80) of the fuel stream is introduced into the combustion chamber (34) through at least one main outlet opening (38) of the first passage (28) and a branched-off portion (82) of the fuel stream is introduced, downstream of introduction thereof into the fuel passage (28) and upstream of the main outlet opening (38), into at least one second passage (26) via at least one connection duct (54) branching off from the first passage (28), wherein the branched-off portion (82) of the fuel stream is introduced into the combustion chamber separately from the remaining fuel stream (80), such that the sub-streams, after exit thereof from the burner, are combusted in the combustion chamber (34) with different dwell times or dwell time profiles,
    wherein
    the fraction and/or the inflow profile and/or the division over the at least one connection duct (54) of the branched-of portion (82) of the fuel stream is adjusted prior to start-up of the burner and/or during operation of the burner, characterized in that adjustment of the fraction and/or the penetration depth and/or the division over the at least one connection duct (54) proceeds by adapting at least one flow guide means (62) arranged in the fuel passage (28) and/or one adjusting element arranged in the region of the connection ducts, such that fluctuations in heat release are fed back to a lesser extent into the pressure fluctuations in the combustion chamber.
17. Method according to Claim 16,
    characterized in that
    the remaining fuel stream (80) and the branched-off portion (82) of the fuel stream are introduced substantially coaxially to one another into the combustion chamber.
18. Method according to one of Claims 16 or 17,
    characterized in that
    adaptation of the at least one flow guide means (62) and/or of the at least one adjusting element may proceed by exchange of the flow guide means and/or the adjusting element and/or adaptation of the shape and/or position thereof.

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