System and method for reducing combustion dynamics

Abstract

System for reducing combustion dynamics in a gas turbine (10), comprising: a first and a second combustion chamber arrangement (14) arranged about an axis (78) of a rotor (18) of the gas turbine (10), each combustion chamber arrangement (14) comprising a cap arrangement (50) extending radially over the combustion chamber arrangement (14) and a combustion chamber (38) arranged downstream of the cap arrangement (50), the cap arrangement (50) comprising an upstream surface (82) and a downstream surface (84) axially separated from the upstream surface (82) which defines an upstream end of the combustion chamber (38) of the respective combustion chamber arrangement (14); wherein each cap assembly (50) contains several tubes (36) extending axially through the cap assembly (50) to provide a flow connection through the cap assembly (50) to the combustion chamber (38), wherein each tube (36) has a fuel injector (94) extending through each tube (36) to provide a flow connection into each tube (36); and wherein each cap arrangement (50) has an axial length (80) defined between the upstream surface (82) and the downstream surface (84) of the respective cap arrangement (50), wherein the axial length (80) of the cap arrangement (50) in the first combustion chamber arrangement (14) differs from the axial length (80) of the cap arrangement (50) in the second combustion chamber arrangement (14).

Description

AREA OF INVENTION

[0001] The present invention relates generally to a system and a method for reducing combustion dynamics. In specific embodiments, the invention can be used in a gas turbine or in another turbo engine. BACKGROUND TO THE INVENTION

[0002] Combustion chamber assemblies are generally used in industrial and commercial applications to ignite fuel, producing combustion gases at high temperature and pressure. For example, gas turbines and other turboprop engines typically incorporate one or more combustion chamber assemblies to generate power or thrust. A typical gas turbine used to generate electricity has an axial compressor at the front end, multiple combustion chamber assemblies around the middle, and a turbine at the rear end. Ambient air enters the compressor as a working fluid, and the compressor progressively imparts kinetic energy to the working fluid to produce a compressed working fluid in a high-energy state.The compressed working fluid leaves the compressor and flows through one or more fuel nozzles and / or tubes in the combustion chamber assembly, where it mixes with fuel before being ignited to produce high-temperature, high-pressure combustion gases. These combustion gases then flow to the turbine, where they expand to perform work. For example, the expansion of the combustion gases in the turbine can drive a rotating shaft connected to a generator to produce electricity.

[0003] Numerous factors influence the design and operation of combustion chamber assemblies. For example, higher combustion gas temperatures generally increase the thermodynamic efficiency of combustion chamber assemblies. However, higher combustion gas temperatures also promote flame-holding conditions under which the combustion flame migrates towards the fuel supplied by the fuel nozzles, potentially leading to accelerated wear of the fuel nozzles in a relatively short time. Furthermore, higher combustion gas temperatures generally increase the separation rate of diatomic nitrogen, which promotes the formation of nitrogen oxides (NOx).In contrast, a lower combustion gas temperature, which is associated with a reduced fuel flow and / or a part-load operating condition (throttling), generally reduces the chemical reaction rates of the combustion gases, which promotes the formation of carbon monoxide and unburned hydrocarbons.

[0004] Although some combustion chamber designs effectively permit higher operating temperatures while preventing flame propagation and controlling unwanted emissions, they can, under specific operating conditions, generate combustion instabilities. These instabilities result from an interaction or coupling of the combustion process or flame dynamics with one or more acoustic resonance frequencies of the combustion chamber design. For example, a mechanism of combustion instability can occur when acoustic pressure pulses at a fuel supply port cause a mass flow rate fluctuation, leading to a fluctuation in the fuel / air ratio in the flame zone. If the resulting fuel / air ratio fluctuation and the acoustic pressure pulses exhibit some phase behavior (e.g., are nearly in phase), a self-excited feedback loop develops.This mechanism and the resulting degree of combustion dynamics depend on the delay time, known in the art as the convective time (τ), which exists between fuel injection and the point at which the fuel reaches the flame zone. As the convective time increases, the frequency of combustion instabilities decreases, and conversely, as the convective time decreases, the frequency of combustion instabilities increases. The result is combustion dynamics that can reduce the service life of one or more combustion chamber assembly components and / or downstream components. For example, the combustion dynamics can generate pressure pulses inside the fuel nozzles and / or combustion chambers, which can adversely affect the fatigue life of these components, the stability of the combustion flame, the design limits for flame retention, and / or undesirable emissions.Alternatively or additionally, combustion dynamics that are in phase and coherent can, at specific frequencies and with sufficient amplitudes, generate undesirable resonant vibrations in the turbine and / or other downstream components. By shifting the frequency of the combustion instability in one or more combustion chamber arrays relative to the others, the overall coherence of the combustion chamber system is reduced, and the coupling between combustion chambers is diminished. This reduces the ability of the combustion chamber array tone to induce a resonant vibration in downstream components and, furthermore, promotes destructive interference between combustion chamber arrays, thus reducing the amplitudes of the combustion dynamics.Consequently, a system that adjusts the phase and / or coherence of the combustion dynamics produced by each combustion chamber arrangement would advantageously improve the thermodynamic efficiency of the combustion chamber arrangements, protect against accelerated wear, promote flame stability and / or reduce unwanted emissions over a wide range of operating levels.

[0005] DE 10 2007 042 059 A1 discloses a system for reducing combustion dynamics in a gas turbine with multiple combustion chamber arrangements grouped around an axis of a gas turbine rotor, wherein each combustion chamber arrangement includes a cap arrangement extending radially over the combustion chamber arrangement and a combustion chamber located downstream of the cap arrangement. The cap arrangement has an upstream surface and a downstream surface axially separated from the upstream surface, defining an upstream end of the combustion chamber of the respective combustion chamber arrangement. Several premixing tubes extend axially through the cap arrangement and each has an outlet opening on the downstream surface of the cap arrangement to provide a flow connection through the cap arrangement to the combustion chamber.Fuel injectors are arranged in each premix tube to inject fuel into a premix channel formed within the respective tube. In one embodiment, the downstream surface of the cap arrangement is inclined relative to a central axis of the combustion chamber arrangement, thus defining an inclined outlet plane on which the outlet openings of the respective premix tubes are positioned at different axial locations.

[0006] DE 10 2011 055 472 A1 discloses a combustion chamber arrangement of a gas turbine with a cap arrangement accommodating several fuel nozzles, each comprising a plurality of premixing tubes extending through the cap arrangement and into the combustion chamber of the combustion chamber arrangement. In embodiments, the outlet ends of the premixing tubes project to varying distances beyond a downstream end face of the cap arrangement into the combustion chamber.

[0007] DE 10 2009 003 639 A1 discloses a combustion chamber arrangement of a gas turbine, which includes several fuel nozzles with premixing tubes, comprising fuel injectors and swirl vanes, which are arranged at different axial positions to reduce the combustion dynamics, so that they define different axial distances of the fuel injector openings and / or the swirl vanes to the combustion chamber.

[0008] US 5 943 866 A describes different systems for reducing combustion dynamics in a gas turbine with a combustion chamber arrangement that includes multiple fuel nozzles having fuel injectors or fuel injection ports that are arranged at different axial positions and thus have different axial distances to the combustion chamber. BRIEF DESCRIPTION OF THE INVENTION

[0009] The features and advantages of the invention are presented below in the following description, or may be obvious from the description, or may be experienced through the practice of the invention.

[0010] According to one aspect of the invention, a system for reducing combustion dynamics in a gas turbine includes: a first and a second combustion chamber arrangement grouped around an axis of a rotor of the gas turbine, each combustion chamber arrangement comprising a cap arrangement extending radially over the combustion chamber arrangement and a combustion chamber arranged downstream of the cap arrangement, the cap arrangement comprising an upstream surface and a downstream surface axially separated from the upstream surface, defining an upstream end of the combustion chamber of the respective combustion chamber arrangement; wherein each cap assembly contains several tubes extending axially through the cap assembly to provide a fluid connection through the cap assembly to the combustion chamber, wherein each tube has a fuel injector extending through each tube to provide a fluid connection into each tube; and wherein each cap arrangement has an axial length defined between the upstream surface and the downstream surface of the respective cap arrangement, wherein the axial length of the cap arrangement in the first combustion chamber arrangement differs from the axial length of the cap arrangement in the second combustion chamber arrangement.

[0011] The multiple tubes in each cap assembly can be grouped into multiple tube bundles arranged radially across the cap assembly, the fuel injector being positioned through each tube at a fourth axial distance from the combustion chamber, and the fourth axial distance being different for at least two tube bundles in the first combustion chamber assembly.

[0012] Furthermore, or alternatively, each cap assembly additionally has a fuel nozzle extending axially through the cap assembly to provide a flow connection through the cap assembly to the combustion chamber, each fuel nozzle comprising: an axially extending central base body, a jacket surrounding at least a section of the axially extending central base body, several guide vanes extending radially between the central base body and the jacket, a first fuel supply opening through at least one of the several guide vanes at a first axial distance from the combustion chamber, a second fuel supply opening through the central base body at a second axial distance from the combustion chamber, the several guide vanes being arranged at a third axial distance from the combustion chamber.

[0013] Furthermore or alternatively, at least one of the axial distances differs, be it the first axial distance in the first combustion chamber arrangement from the first axial distance in the second combustion chamber arrangement, the second axial distance in the first combustion chamber arrangement from the second axial distance in the second combustion chamber arrangement, or the third axial distance in the first combustion chamber arrangement from the third axial distance in the second combustion chamber arrangement.

[0014] Furthermore, or alternatively, at least two of the axial distances differ, be it the first axial distance from the first axial distance in the second combustion chamber arrangement, the second axial distance in the first combustion chamber arrangement from the second axial distance in the second combustion chamber arrangement, or the third axial distance in the first combustion chamber arrangement from the third axial distance in the second combustion chamber arrangement.

[0015] Furthermore, or alternatively, the first axial distance in the first combustion chamber arrangement differs from the first axial distance in the second combustion chamber arrangement, the second axial distance in the first combustion chamber arrangement differs from the second axial distance in the second combustion chamber arrangement, and the third axial distance in the first combustion chamber arrangement differs from the third axial distance in the second combustion chamber arrangement.

[0016] In addition, or alternatively, each combustion chamber arrangement has multiple fuel nozzles, and at least one of the axial distances, be it the first, the second and / or the third axial distance, is different for at least two fuel nozzles in the first combustion chamber arrangement.

[0017] In addition, or alternatively, each combustion chamber arrangement has multiple fuel nozzles, and at least two of the axial distances, be they the first, the second, or the third axial distance, differ for at least two fuel nozzles in the first combustion chamber arrangement.

[0018] In addition, or alternatively, each combustion chamber arrangement has multiple fuel nozzles, and the first, second, or third axial distances for at least two fuel nozzles in the first combustion chamber arrangement differ.

[0019] According to another aspect of the invention, a system for reducing combustion dynamics in a gas turbine includes: a first and a second combustion chamber arrangement grouped around an axis of a rotor of the gas turbine, each combustion chamber arrangement comprising a cap arrangement extending radially over the combustion chamber arrangement and a combustion chamber arranged downstream of the cap arrangement, the cap arrangement comprising an upstream surface and a downstream surface axially separated from the upstream surface, defining an upstream end of the combustion chamber of the respective combustion chamber arrangement; wherein each cap assembly has a fuel nozzle extending axially through the cap assembly to provide a flow connection through the cap assembly to the combustion chamber, wherein each fuel nozzle comprises: an axially extending central base body, a jacket surrounding at least a portion of the axially extending central base body, several guide vanes extending radially between the central base body and the jacket, a first fuel supply opening through at least one of the several guide vanes at a first axial distance from the combustion chamber, a second fuel supply opening through the central base body at a second axial distance from the combustion chamber, wherein the several guide vanes are arranged at a third axial distance from the combustion chamber, the first, second, and third distances being different from one another; and wherein each cap arrangement has an axial length defined between the upstream surface and the downstream surface of the respective cap arrangement, wherein the axial length of the cap arrangement in the first combustion chamber arrangement differs from the axial length of the cap arrangement in the second combustion chamber arrangement.

[0020] In the system according to the further aspect, at least one of the axial distances may differ, be it the first axial distance in the first combustion chamber arrangement from the first axial distance in the second combustion chamber arrangement, the second axial distance in the first combustion chamber arrangement from the second axial distance in the second combustion chamber arrangement, or the third axial distance in the first combustion chamber arrangement from the third axial distance in the second combustion chamber arrangement.

[0021] In the system, at least one of the axial distances can differ, be it the first axial distance in the first combustion chamber arrangement from the first axial distance in the second combustion chamber arrangement, the second axial distance in the first combustion chamber arrangement from the second axial distance in the second combustion chamber arrangement, or the third axial distance in the first combustion chamber arrangement from the third axial distance in the second combustion chamber arrangement.

[0022] In the system, the first axial distance in the first combustion chamber arrangement can differ from the first axial distance in the second combustion chamber arrangement, the second axial distance in the first combustion chamber arrangement can differ from the second axial distance in the second combustion chamber arrangement, and the third axial distance in the first combustion chamber arrangement can differ from the third axial distance in the second combustion chamber arrangement.

[0023] In the system, each combustion chamber arrangement can have multiple fuel nozzles, wherein at least one of the axial distances, be it the first, the second and / or the third axial distance, is different for at least two fuel nozzles in the first combustion chamber arrangement.

[0024] In the system, each combustion chamber arrangement can have multiple fuel nozzles, wherein at least two of the axial distances, be they the first, the second, or the third axial distance, differ for at least two fuel nozzles in the first combustion chamber arrangement. Furthermore, each combustion chamber arrangement can have multiple fuel nozzles, wherein the first, the second, and the third axial distances differ for at least two fuel nozzles in the first combustion chamber arrangement.

[0025] The characteristics and aspects of such and other exemplary embodiments will become more understandable to the person skilled in the art after reading the description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] A complete and practically applicable description of the present invention, which includes the best mode of the invention for the person skilled in the art, is described in more detail in the following description in conjunction with the accompanying figures: Fig. Figure 1 shows a simplified lateral sectional view of an exemplary gas turbine according to different embodiments of the present invention; Fig. Figure 2 shows an exemplary combustion chamber arrangement according to different embodiments of the present invention in a simplified lateral sectional view; Fig. Figure 3 shows an upstream top view of the Fig. 2 cap arrangement shown according to an embodiment of the present invention; Fig. Figure 4 shows an upstream top view of the [unclear] in Fig. 2 cap arrangement shown according to a modified embodiment of the present invention; Fig. 5 shows an upstream top view of the Fig. 2 cap arrangement shown according to a modified embodiment of the present invention; Fig. Figure 6 shows a side sectional view of the head end of the in Fig. 3 combustion chamber arrangement shown along the section line AA according to an embodiment of the present invention; Fig. Figure 7 shows a system for reducing combustion dynamics according to a first embodiment of the present invention; Fig. Figure 8 shows a system for reducing combustion dynamics according to a second embodiment of the present invention; Fig. Figure 9 shows a side sectional view of the head end of the in Fig. 5 combustion chamber arrangement shown along the section line BB according to an embodiment of the present invention; Fig. Figure 10 shows a system for reducing combustion dynamics according to a third embodiment of the present invention; Fig. Figure 11 shows a system for reducing combustion dynamics according to a fourth embodiment of the present invention; and Fig. Figure 12 illustrates an exemplary graph of the dynamics of a combustion chamber arrangement according to different embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] The present embodiments of the invention will now be discussed in detail, with one or more of the examples being illustrated in the accompanying drawings. The detailed description uses alphanumeric designations to refer to features in the figures. Similar or identical designations have been used in the figures and in the description to refer to similar or identical elements of the invention. In the sense used here, the terms "first," "second," and "third" may be used interchangeably to distinguish one component from another and are not intended to denote the location or significance of the individual components. Furthermore, the terms "upstream" and "downstream" refer to the relative arrangement of the components in a flow path.For example, component A is located upstream of component B if a fluid flows from component A to component B. Conversely, component B is located downstream of component A if component B receives a fluid flow from component A.

[0028] All examples serve to illustrate the invention and are not intended to limit it. The person skilled in the art will readily recognize that modifications and changes can be made to the present invention without deviating from the scope of protection or the subject matter of the invention. For example, features illustrated or described as part of one embodiment can be applied to another embodiment to produce yet another embodiment. The present invention is therefore intended to cover such modifications and deviations, insofar as they fall within the scope of protection of the appended claims and their equivalent forms.

[0029] Various embodiments of the present invention include a system and a method for reducing combustion dynamics to improve thermodynamic efficiency, promote flame stability, and / or reduce undesirable emissions over a wide range of operating levels. The system and the method generally comprise multiple combustion chamber arrangements, and each combustion chamber arrangement includes one or more fuel nozzles and / or tubes, as well as a combustion chamber located downstream of the fuel nozzle(s) and / or tubes. Each fuel nozzle includes one or more fuel supply ports and / or radially extending guide vanes, and each tube includes one or more fuel injectors.The system and method include various means of generating a combustion instability frequency in the first combustion chamber arrangement that differs from the combustion instability frequency in the second combustion chamber arrangement. Thus, various embodiments of the present invention can enable longer operating times, extended service life and / or longer maintenance intervals, improved flame control design limits, and / or a reduction in undesirable emissions. Although embodiments of the present invention are described generally in connection with combustion dynamics in a gas turbine for illustrative purposes, it will be readily apparent to those skilled in the art that embodiments of the present invention can be applied to any combustion dynamics and are not limited to a gas turbine unless specifically mentioned in the claims.

[0030] Fig. Figure 1 shows a simplified sectional view of an exemplary gas turbine 10, which can employ different embodiments of the present invention. As shown, the gas turbine 10 can generally comprise: a compressor section 12 at the front, several combustion chambers 14 arranged radially around the center in a combustion chamber, and a turbine section 16 at the rear. The compressor section 12 and the turbine section 16 can utilize a common impeller 18, which is connected to a generator 20 to produce electricity. A working fluid 22, e.g., ambient air, can enter the compressor section 12 and pass through alternating stages of stationary guide vanes 24 and rotating blades 26.A compressor casing 28 contains the working fluid 22, while the stationary guide vanes 24 and the rotating impeller blades 26 accelerate and deflect the working fluid 22 to produce a continuous flow of compressed working fluid 22. The majority of the compressed working fluid 22 flows through a compressor outlet manifold 30 to the combustion chambers 14. A combustion chamber casing 32 can partially or completely surround each combustion chamber assembly 14 along its circumference to receive the compressed working fluid 22 flowing from the compressor section 12. Fuel can be mixed with the compressed working fluid 22 in one or more fuel nozzles 34 and / or tubes 36. Suitable fuels include, for example, blast furnace gas, coke oven gas, natural gas, vaporized liquefied natural gas (LNG), hydrogen, and / or propane.The mixture of fuel and compressed working fluid 22 can then flow into a combustion chamber 38, where it ignites to generate combustion gases at high temperature and high pressure. A transition channel 40 surrounds at least one section of the combustion chamber 38, and the combustion gases flow through the transition channel 40 to the turbine section 16.

[0031] The turbine section 16 can contain alternating stages of stationary guide vanes 42 and rotating blades 44. The stationary guide vanes 42 direct the combustion gases to the next stage of rotating blades 44, and the combustion gases expand as they sweep over the rotating blades 44, thus driving the rotating blades 44 and the impeller 18. The combustion gases then flow to the next stage of stationary guide vanes 42, which redirect the combustion gases to the next stage of rotating blades 44, and the process is repeated for the subsequent stages.

[0032] The combustion chamber arrangements 14 can be any combustion chamber arrangements known from the prior art, and the present invention is not limited to any particular combustion chamber design unless specifically mentioned in the claims. Fig. Figure 2 shows a simplified side sectional view of an exemplary combustion chamber arrangement 14 according to different embodiments of the present invention. The combustion chamber housing 32 surrounds at least a section of the combustion chamber arrangement 14 to receive the compressed working fluid 22 flowing from the compressor 12. As shown in Fig. As shown in Figure 2, the combustion chamber housing 32 can be connected to or include an end cover 46 that extends radially over at least one section of each combustion chamber 14 to provide an intermediate element for supplying fuel, diluent, and / or other additives to each combustion chamber assembly 14. Furthermore, the combustion chamber housing 32 and the end cover 46 can interact to form at least one section of a head end 48 within each combustion chamber assembly 14. The fuel nozzles 34 and / or tubes 36 are arranged radially in a cap assembly 50 that extends radially over the combustion chamber 14 downstream of the head end 48. A combustion chamber wall 52 can be connected to the cap assembly 50 to form at least one section of the combustion chamber 38 downstream of the cap assembly 50.In this way, the working fluid 22 can, for example, flow through flow holes 54 formed in a baffle sleeve 56 and along the outside of the transition channel 40 and the combustion chamber wall 52 to convectively cool the transition channel 40 and the combustion chamber wall 52. When the working fluid 22 reaches the head end 48, it reverses its direction, and the fuel nozzles 34 and / or the tubes 36 provide a flow connection for the working fluid 22 to flow through the cap assembly 50 and into the combustion chamber 38.

[0033] Although generally depicted as cylindrical, the radial cross-section of the fuel nozzles 34 and / or the tubes 36 can have any geometric shape, and the present invention is not limited to any particular radial cross-section unless specifically mentioned in the claims. Furthermore, different embodiments of the combustion chamber arrangement 14 may include different numbers and groupings of fuel nozzles 34 and / or tubes 36 in the cap arrangement 50, and Fig. Figures 3-5 show upstream top views of exemplary groupings of the fuel nozzles 34 and / or tubes 36 in the cap arrangement 50 within the scope of protection of the present invention. As shown in Fig. As shown in Figure 3, for example, several fuel nozzles 34 can be grouped radially around a single fuel nozzle 34. In a variation, the tubes 36 can be arranged as shown in Figure 3. Fig. As shown in Figure 4, the tubes 36 can be arranged radially over the entire cap assembly 50, and the tubes 36 can be distributed into several groups to perform multiple fuel supply operating modes across the operating range of the combustion chamber 14. For example, the tubes 36 can be grouped into several circular tube bundles 58, which, as shown in Figure 4, are arranged radially over the entire cap assembly 50, and the tubes 36 can be distributed into several groups to perform several fuel supply operating modes over ... Fig. 4 shows that they are arranged around the circumference of a central tube bundle 60. In a variation, as shown in Fig. Figure 5 shows several pie-slice-shaped tube bundles 62 surrounding a single fuel nozzle 34 along its circumference. During base-load operating conditions, each fuel nozzle 34 and each in Fig. Fuel is supplied to the tube bundles 58, 60, 62 shown in Figures 3-5, whereas the fuel flow from the central fuel nozzle 34 or from the central tube bundle 60 and / or from one or more circularly arranged fuel nozzles 34 or circular or pie-shaped tube bundles 58, 62 can be reduced or completely eliminated under reduced or throttled operating conditions. A person skilled in the art will readily conceive of several other shapes and groupings for the fuel nozzles 34, tubes 36, and tube bundles 58, 60, 62 based on the teaching presented here, and the specific shape and grouping of the fuel nozzles 34, the tubes 36, and the tube bundles 58, 60, 62 do not entail any limitations of the present invention, unless specifically mentioned in the claims.

[0034] Fig. Figure 6 shows a side cross-sectional view of the head end 48 of the in Fig. 3 shown combustion chamber arrangement 14 along the section line AA according to an embodiment of the present invention. As in Fig. 3 and Fig. As shown in Figure 6, the combustion chamber arrangement 14 can include several fuel nozzles 34 grouped radially around a central fuel nozzle 34, which is substantially aligned with an axial centerline 64 of the combustion chamber arrangement 14. Each fuel nozzle 34 can include a central base body 66 extending axially downstream of the end cover 46 and a jacket 68 surrounding at least a portion of the central base body 66 to form an annular passage 70 between the central base body 66 and the jacket 68. One or more blades 72 can extend radially between the central base body 66 and the jacket 68, and the blades 72 can be angled or curved to impart swirl to the working fluid 22 flowing between the central base body 66 and the jacket 68 through the annular passage 70.The blades 72 and / or the central base body 66 can contain one or more fuel supply openings 74. In this way, fuel can be supplied through the central base body 66 and / or through the blades 72, and the fuel supply openings 74 provide a flow connection for the fuel so that it flows into the annular passage 70 and mixes with the working fluid 22 before the mixture reaches the combustion chamber 38.

[0035] If the fuel nozzles 34 are placed in the combustion chamber 14, e.g. in the one in Fig. In the exemplary combustion chamber arrangement 14 shown in section 2, the combustion process taking place in the combustion chamber 38 can generate heat release fluctuations, which in turn are coupled to one or more sound vibration modes of the combustion chamber arrangement 14, resulting in combustion instabilities. A specific mechanism that can generate combustion instabilities occurs when the sound pulsations excited by the heat release fluctuations cause fluctuations in the mass flow rate through the fuel supply openings 74. For example, the pressure pulses associated with the combustion flames can propagate upstream from the combustion chamber 38 into each annular channel 70.When the pressure pulses reach the fuel supply ports 74 and / or blades 72, they can impair the fuel flow through the fuel supply ports 74 and / or over the blades 72, causing fluctuations in the concentration of the fuel-air mixture flowing downstream towards the combustion flame. This fuel / air ratio fluctuation then propagates downstream to the flame region, where it causes a heat release fluctuation. Provided that the resulting heat release fluctuation is approximately in phase with the pressure fluctuations, it will further promote heat release fluctuations, creating a continuous feedback loop.If, however, the resulting heat release fluctuation and the pressure fluctuations are out of phase, the magnitude of the combustion instability frequency associated with the specific fuel nozzle 34 is reduced by destructive superposition. The combustion instability frequencies associated with the fuel nozzles 34 can, in turn, interact with each other either constructively or destructively to increase or decrease the amplitude of the combustion dynamics associated with the specific combustion chamber arrangement 14.

[0036] The resulting combustion instability frequencies will be a function of the time it takes for the acoustic pressure pulse to reach the fuel supply opening and subsequently for the resulting fuel / air ratio disturbance to reach the flame zone. This time is known from the prior art as the convective time τ. The combustion instability frequencies arising from the interaction between the fuel / air ratio fluctuations and the acoustic pressure fluctuation are therefore inversely proportional to the axial distance between the fuel supply openings 74 and / or the blades 72 and the combustion chamber 38 (i.e., the end of the fuel nozzles 34 or the end of the jackets 68).In specific embodiments, these combustion instability frequencies can be set and / or tuned in one or more fuel nozzles 34 to influence the combustion dynamics associated with the individual combustion chamber arrangement 14. In the [reference to be added] Fig. 3 and Fig. In the specific embodiment shown in Figure 6, the combustion chamber arrangement 14 can, for example, contain several fuel nozzles 34, wherein the axial distance 76 between the fuel supply openings 74 and / or the blades 72 and the combustion chamber 38 is different for each fuel nozzle 34. Accordingly, the combustion instability frequency generated for each fuel nozzle 34 will differ slightly, so that any constructive interference between the fuel nozzles 34 is mitigated or prevented from increasing the amplitude of the combustion dynamics associated with the specific combustion chamber arrangement 14.It will be readily apparent to a person skilled in the art, based on the teaching presented here, that several combinations of changes in the axial distances 76 between the fuel supply openings 74 and / or the blades 72 and the combustion chamber 38 are possible in order to achieve a desired combustion instability frequency for each fuel nozzle 34 and / or a desired combustion dynamics for the specific combustion chamber arrangement 14. For example, in specific embodiments, the axial distances 76 between the fuel supply openings 74 and / or the blades 72 and the combustion chamber 38 may be the same or different for some or all of the fuel nozzles 34 in a specific combustion chamber arrangement 14, and the present invention is not limited to any specific combination of axial distances 76 unless specifically mentioned in the claims.

[0037] The combustion dynamics associated with several combustion chambers 14 installed in the gas turbine 10 can interact with each other in either a building-up or a breakdown manner to increase or decrease the amplitude and / or coherence of the combustion dynamics associated with the gas turbine 10. In specific embodiments, the combustion instability frequencies and / or combustion dynamics associated with one or more combustion chamber arrangements 14 can be adjusted and / or tuned to influence the interaction with the combustion dynamics of another combustion chamber arrangement 14 and thus the combustion dynamics associated with the gas turbine 10. For example, [reference to relevant example] Fig. 7. A system for reducing combustion dynamics and / or the coherence of combustion dynamics according to a first embodiment of the present invention. In the Fig. In the special embodiment shown in 7, several combustion chambers 14 are shown, as in Fig. 3 and Fig. 6 shown, arranged around an axis 78. The axis 78 can, for example, coincide with that of the rotor 18 in the gas turbine 10, which connects the compressor section 12 with the turbine section 16, but the present invention is not limited to the specific orientation of the axis 78 or the specific grouping of the combustion chamber arrangements 14 around the axis 78.

[0038] As in Fig. As shown in Figure 7, each combustion chamber arrangement 14 contains several fuel nozzles 34, wherein the combustion chamber 38 is as previously shown in Figure 7. Fig. 2, Fig. 3 and Fig. The system is located downstream of the fuel nozzles 34, as described in Section 6. Furthermore, the system also includes means for generating a combustion instability frequency in one combustion chamber arrangement 14 that differs from the combustion instability frequency in the other combustion chamber arrangement 14. By generating a combustion instability frequency in one combustion chamber arrangement 14 that differs from the combustion instability frequency in the other combustion chamber arrangement 14, coherent or constructive interference between the combustion instability frequencies, which could increase the amplitude of the combustion dynamics or enhance the coherence of the combustion dynamics of two or more combustion chamber arrangements 14, is reduced or prevented.The design for the means can include a difference between the two combustion chamber arrangements 14 between one or more of the axial distances 76 between the fuel supply openings 74 and the combustion chamber 38 and / or between the blades 72 and the combustion chamber 38. In the in . Fig. In the specific embodiment shown in Figure 7, for example, each axial distance 76 between the fuel supply openings 74 and the combustion chamber 38 and between the blades 72 and the combustion chamber 38 differs between the two combustion chamber arrangements 14. As a result, the means generates different combustion instability frequencies in the two combustion chamber arrangements 14. It will be readily apparent to a person skilled in the art, based on the teaching presented here, that several combinations of changes in the axial distances 76 between the fuel supply openings 74 and the combustion chamber 38 and / or between the blades 72 and the combustion chamber 38 are possible in order to produce a combustion instability frequency in one combustion chamber arrangement 14 that differs from the combustion instability frequency in the other combustion chamber arrangement 14.For example, in special embodiments, one or more axial distances 76 between the fuel supply openings 74 and the combustion chamber 38 and / or between the blades 72 and the combustion chamber 38 for one or more of the fuel nozzles 34 in a special combustion chamber arrangement 14 may be the same or different compared to the other combustion chamber arrangement 14, provided that the axial distances 76 between the two combustion chamber arrangements 14 are not all the same; and the present invention is not limited to any special combination of axial distances 76 unless specifically mentioned in the claims.

[0039] Fig. Figure 8 illustrates a system for reducing combustion dynamics according to a second embodiment of the present invention. As shown in Fig. As shown in Figure 8, each combustion chamber arrangement 14 also has several fuel nozzles 34, with the combustion chamber 38 being, as before according to Fig. 2, Fig. 3, Fig. 6 and Fig. 7 described, is arranged downstream of the fuel nozzles 34. Furthermore, the axial positions of the fuel channels 74 and / or the blades 72 can be the same or different in each combustion chamber arrangement 14. For example, the axial positions of the fuel channels 74 and the blades 72 differ in the one described in Fig. 8 shown special embodiment within the same combustion chamber arrangement 14, however the axial positions of the fuel channels 74 and the blades 72 are repeated in both combustion chamber arrangements 14.

[0040] The in Fig. The embodiment shown in Figure 8 also includes means for generating a combustion instability frequency or resonance frequency in one combustion chamber arrangement 14 that differs from the combustion instability frequency or resonance frequency in the other combustion chamber arrangement 14. In this particular embodiment, the design for the means can include a difference in the axial length 80 of the cap arrangement 50 in one combustion chamber arrangement 14 compared to the axial length 80 of the cap arrangement in the other combustion chamber arrangement 14.Because the axial positions of the fuel channels 74 and the blades 72 are repeated in both combustion chamber arrangements 14, the difference in axial lengths 80 between the two combustion chamber arrangements 14 generates a corresponding difference in axial distances 76 between the fuel supply openings 74 and the combustion chamber 38 and between the blades 72 and the combustion chamber 38 between the two combustion chamber arrangements 14. The difference in axial distances 76 between the two combustion chamber arrangements 14 generates a corresponding difference in combustion instability or resonance frequencies between the two combustion chamber arrangements 14.It will be readily apparent to a person skilled in the art, based on the teaching presented here, that several combinations of changes in the axial distances 76 between the fuel supply openings 74 and the combustion chamber 38 and / or the blades 72 and the combustion chamber 38 are possible in order to produce in one combustion chamber arrangement 14 a combustion instability or resonance frequency which differs from the combustion instability or resonance frequency in the other combustion chamber arrangement 14.For example, in special embodiments, one or more axial distances 76 between the fuel supply openings 74 and the combustion chamber 38 and / or between the blades 72 and the combustion chamber 38 for one or more of the fuel nozzles 34 in a special combustion chamber arrangement 14 may be the same or different compared to the other combustion chamber arrangement 14, and the present invention is not limited to any special combination of axial distances 76 unless specifically mentioned in the claims.

[0041] Fig. Figure 9 illustrates a side sectional view of the head end 48 of the in Fig. The combustion chamber arrangement 14 shown in Figure 5 is shown along section line BB according to an embodiment of the present invention. As shown, the cap arrangement 50 extends radially over the combustion chamber arrangement 14 and has an upstream surface 82 that is axially separated from a downstream surface 84. The upstream and downstream surfaces 82, 84 can be substantially planar or straight and oriented perpendicular to the general flow of the working fluid 22 through the cap arrangement 50. Also in the embodiment shown in Figure 5, the cap arrangement 50 is arranged in a manner that allows for a lateral, vertical, and horizontal orientation of the combustion chamber arrangement 14. Fig. In the specific embodiment shown in Figure 9, the fuel nozzle 34 is essentially aligned with the axial centerline 64 of the cap assembly 50 and extends through the cap assembly 50 to provide a flow connection through the cap assembly 50 to the combustion chamber 38. The fuel nozzle 34 can comprise any suitable design known to those skilled in the art for mixing fuel with the working fluid 22 before it enters the combustion chamber 38, and the present invention is not limited to any particular structure or design unless specifically mentioned in the claims. For example, the fuel nozzle 34 can be, as shown in Figure 9, Fig. Figure 9 shows the central base body 66, the mantle 68, the annular channel 70, the blades 72 and the fuel supply openings 74, as previously described with reference to the one in Fig. The embodiment shown in section 6 is described.

[0042] As in Fig. 5 and Fig. As shown in Figure 9, the tubes 36 can be arranged in pie-shaped tube bundles 62 in a circular arrangement around the fuel nozzle 34, and they can extend from the upstream surface 82 through the downstream surface 84 of the cap assembly 50. Each tube 36 generally has an inlet 86 near the upstream surface 82 and an outlet 88 near the downstream surface 84 to provide a flow connection through the cap assembly 50 and into the combustion chamber 38 located downstream of the tubes 36.

[0043] As in Fig. As shown in Figure 9, the upstream and downstream surfaces 82, 84 can at least partially form a fuel collection chamber 90 within the cap assembly 50. A fuel channel 92 can extend from the housing 32 and / or the end cover 46 through the upstream surface 82 to provide a flow connection for fuel flowing into the fuel collection chamber 90. One or more tubes 36 can contain a fuel injector 94 extending through the tubes 36 to provide a flow connection from the fuel collection chamber 90 into the tubes 36. The fuel injectors 94 can be angled radially, axially, and / or azimuthally to propel and / or swirl the fuel flowing through the fuel injectors 94 and into the tubes 36.The working fluid 22 can thus flow into the pipe inlets 86, and fuel from the fuel channel 92 can flow around the pipes 36 arranged in the fuel collection chamber 90 to convectively cool the pipes 36 before flowing through the fuel injectors 94 and into the pipes 36 to mix with the working fluid 22. The mixture of fuel and working fluid can then flow through the pipes 36 and into the combustion chamber 38.

[0044] As previously with reference to the in Fig. As described in the embodiment shown in section 6, the combustion process taking place in the combustion chamber 38 can be carried out if the tubes 36 are in the combustion chamber 14, e.g. in the Fig. The exemplary combustion chamber arrangement 14 shown in the second example is installed and produces heat release fluctuations, which in turn are coupled to one or more acoustic vibration modes of the combustion chamber arrangement 14, thus causing combustion instabilities. A specific mechanism by which combustion instabilities can be generated occurs when the acoustic pulsations excited by the heat release fluctuations propagate upstream to the fuel injectors 94, where they affect the fuel flow through the fuel injectors 94 and can generate fluctuations in the concentration of the fuel / air mixture flowing downstream towards the combustion flame. This fluctuation in the fuel / air ratio then propagates downstream to the flame region, where it can cause a heat release fluctuation.Provided that the resulting heat release fluctuation is approximately in phase with the pressure fluctuations, it will further promote heat release fluctuations, thus closing a continuous feedback loop. If, however, the resulting heat release fluctuation and the pressure fluctuations are out of phase, destructive interference will reduce the magnitude of the combustion instability frequency associated with the tubes 36, the tube bundles 62, and / or the cap assembly 50. The combustion instability frequencies associated with the tubes 36 and / or the tube bundles 62 can, in turn, interact with each other either constructively or destructively to increase or decrease the amplitude of the combustion dynamics associated with the specific combustion chamber assembly 14.

[0045] The resulting combustion instability frequencies will be a function of the time required for the acoustic pressure pulse to reach the fuel injector 94 and subsequently for the resulting fuel / air ratio disturbance to reach the flame zone. This time is known from the prior art as the convective time τ. The combustion instability frequencies generated by the interaction between the fuel / air ratio fluctuations and the acoustic pressure fluctuation are therefore inversely proportional to the axial distance between the fuel injectors 94 and the combustion chamber 38 (i.e., the tube outlets 88). In specific embodiments, these combustion instability frequencies can be set and / or tuned in one or more tubes 36 and / or tube bundles 62 to influence the combustion dynamics associated with each individual combustion chamber arrangement 14. In the Fig. 5 and Fig. In the specific embodiment shown in Figure 9, the tubes 36 can, for example, have a different axial distance 96 between the fuel injectors 94 and the combustion chamber 38 for each tube bundle 62. Accordingly, the combustion instability frequency will differ slightly for each tube 62, thus mitigating or preventing any constructive interference between the tube bundles 62 from increasing the amplitude of the combustion dynamics associated with the specific combustion chamber arrangement 14. It will be readily apparent to a person skilled in the art, based on the teaching presented here, that several combinations of changes in the axial distances 96 between the fuel injectors 94 and the combustion chamber 38 are possible in order to achieve a desired combustion instability frequency for each tube 36 and / or tube bundle 62, and / or a desired combustion dynamics for the specific combustion chamber arrangement 14.For example, in special embodiments, the axial distances 96 between the fuel injectors 94 and the combustion chamber 38 for some or all of the tubes 36 and / or tube bundles 62 in a special combustion chamber arrangement 14 may be the same or different, and the present invention is not limited to any special combination of axial distances 96 unless specifically mentioned in the claims.

[0046] The combustion dynamics associated with several combustion chambers 14 installed in the gas turbine 10 can interact with each other in either a build-up or a reduction-down manner to increase or decrease the amplitude and / or coherence of the combustion dynamics associated with the gas turbine 10. In specific embodiments, the combustion instability frequencies and / or combustion dynamics associated with one or more combustion chamber arrangements 14 can be set and / or tuned to disrupt the interaction with the combustion dynamics of another combustion chamber arrangement 14, and thus the combustion dynamics associated with the gas turbine 10. For example, Fig. 10 a system for reducing combustion dynamics according to a third embodiment of the present invention. In the Fig. In the special embodiment shown in 10, several combustion chambers 14 are as shown in Fig. 5 and Fig. Figure 9 shows the combustion chamber arrangements 14 arranged around an axis 100. The axis 100 can, for example, coincide with the rotor 18 in the gas turbine 10, which connects the compressor section 12 with the turbine section 16; however, the present invention is not limited to the specific orientation of the axis 100 or the specific grouping of the combustion chamber arrangements 14 around the axis 100.

[0047] As in Fig. As shown in Figure 10, each combustion chamber arrangement 14 contains several tubes 36 arranged in pie-shaped tube bundles 62 that surround the fuel nozzle 34 around its circumference, and the combustion chamber 38 is located as previously shown in Figure 10. Fig. 2, Fig. 5 and Fig. 9 described, with respect to the tubes 36, tube bundle 62 and fuel nozzle 34 downstream. Furthermore, the system also includes means for generating a combustion instability frequency in one combustion chamber arrangement 14 that differs from the combustion instability frequency in the other combustion chamber arrangement 14. The design for the means can include a difference between the two combustion chamber arrangements 14 between one or more of the axial distances 96 between the fuel injectors 94 and the combustion chamber 38. In the Fig. In the specific embodiment shown in Figure 10, the axial distance 96 between the fuel injectors 94 and the combustion chamber 38 differs for each tube bundle 62 between the two combustion chamber arrangements 14. As a result, the agent generates different combustion instability frequencies in the two combustion chamber arrangements 14. It will be readily apparent to a person skilled in the art, based on the teaching presented here, that several combinations of changes in the axial distances 96 between the fuel injectors 94 and the combustion chamber 38 are possible in order to produce a combustion instability frequency in one combustion chamber arrangement 14 that differs from the combustion instability frequency in the other combustion chamber arrangement 14.For example, in special embodiments, one or more axial distances 96 between the fuel injectors 94 and the combustion chamber 38 for one or more tubes 36 and / or tube bundles 62 in a special combustion chamber arrangement 14 may be the same or different compared to the other combustion chamber arrangement 14, as long as the axial distances 96 between both combustion chamber arrangements 14 are not all the same, and the present invention is not limited to any special combination of axial distances 96 unless specifically mentioned in the claims.

[0048] Fig. Figure 11 illustrates a system for reducing combustion dynamics according to a fourth embodiment of the present invention. As shown in Fig. As shown in Figure 11, each combustion chamber arrangement 14 also has several tubes 36 arranged in pie-shaped tube bundles 62 that surround the fuel nozzle 34 around its circumference, and the combustion chamber 38 is located downstream of the tubes 36, tube bundles 62 and fuel nozzle 34, as previously shown in Figure 11. Fig. 2, Fig. 5, Fig. 9 and Fig. 10 described. Furthermore, the axial positions of the fuel injectors 94 in each combustion chamber arrangement 14 can be the same or different. In the Fig. In the special embodiment shown in Figure 11, the axial positions of the fuel injectors 94 are different for each tube bundle 62 within the same combustion chamber arrangement 14, while the axial positions of the fuel injectors 94 are repeated for each tube bundle 62 in both combustion chamber arrangements 14.

[0049] The in Fig. The embodiment shown in 11 also includes means for generating a combustion instability or resonance frequency in one combustion chamber arrangement 14 that differs from the combustion instability or resonance frequency in the other combustion chamber arrangement 14. As in the case of the preceding and in Fig. As described in the illustrated embodiment 8, the design for the means can include a difference in the axial length 80 of the cap arrangement 50 in one combustion chamber arrangement 14 compared to the axial length 80 of the cap arrangement in the other combustion chamber arrangement 14. Since the axial positions of the fuel injectors 94 are repeated in both combustion chamber arrangements 14, the difference in axial lengths 80 between the two combustion chamber arrangements 14 generates a corresponding difference in axial distances 96 between the fuel injectors 94 and the combustion chamber 38. The difference in axial distances 96 between the two combustion chamber arrangements 14 generates a corresponding difference in combustion instability or resonance frequencies between the two combustion chamber arrangements 14.It will be readily apparent to a person skilled in the art, based on the teaching presented here, that several combinations of changes in the axial distances 96 between the fuel injectors 94 and the combustion chamber 38 are possible in order to produce a combustion instability or resonance frequency in one combustion chamber arrangement 14 that differs from the combustion instability or resonance frequency in the other combustion chamber arrangement 14. For example, in specific embodiments, one or more axial distances 96 between the fuel injectors 94 and the combustion chamber 38 for one or more tubes 36 and / or tube bundles 62 in a particular combustion chamber arrangement 14 may be the same or different compared to the other combustion chamber arrangement 14, and the present invention is not limited to any specific combination of axial distances 96 unless specifically mentioned in the claims.

[0050] Fig. Figure 12 shows an exemplary graphical representation of combustion chamber arrangement dynamics according to different embodiments of the present invention. The horizontal axis represents a range of combustion instability or resonance frequencies, and the vertical axis represents a range of amplitudes. The in Fig. The system shown in Figure 12 can include three or more combustion chamber assemblies 14, which are installed in the gas turbine 10 or in another turbo engine. By using means to generate a combustion instability frequency in one combustion chamber assembly 14 that differs from the combustion instability frequency in the other combustion chamber assembly 14, each combustion chamber assembly 14 can be adjusted or tuned to achieve a desired combustion instability frequency or combustion dynamics. As shown in Figure 12, the combustion chamber assembly 14 can be set or tuned to achieve a desired combustion instability frequency or combustion dynamics. Fig. As shown in Figure 12, for example, a first group of combustion chamber arrangements 14 can be set and / or tuned to achieve a first combustion instability frequency 102, a second group of combustion chamber arrangements 14 can be set and / or tuned to achieve a second combustion instability frequency 104, and a third group of combustion chamber arrangements 14 can be set and / or tuned to achieve a third combustion instability frequency 106. The first, second, and third combustion instability frequencies 102, 104, and 106 differ slightly from each other and are therefore slightly phase-shifted.Consequently, the combustion instability frequencies 102, 104, 106, which are assigned to the combustion chambers 14, are unable to interact coherently or constructively with each other, which dampens or prevents an increase in combustion dynamics and / or reduces the ability of the combustion chamber system to excite resonance vibrations in the downstream turbine section 16.

[0051] A specialist will readily understand from the teaching presented here that the [document / method] with reference to Fig. The various designs described and illustrated in Figures 1-11 can provide one or more methods for reducing combustion dynamics and / or reducing the coherence of the combustion dynamics in the case of two or more combustion chamber arrangements 14. The methods can, for example, include the step of guiding the working fluid 22 and the fuel through one or more fuel nozzles 34, through tubes 36 and / or through tube bundles 62 into the combustion chambers 38 of several combustion chamber arrangements 14.In specific embodiments, the method can include the step of varying one or more axial distances 76 between the fuel supply openings 74 and the combustion chamber 38 and / or between the blades 72 and the combustion chamber 38, provided that the axial distances 76 are not all the same between all combustion chamber arrangements 14, so that in one combustion chamber arrangement 14 a combustion instability frequency is produced which differs from the combustion instability frequency in the other combustion chamber arrangements 14.In further specific embodiments, the method can include the step of varying one or more axial distances 96 between the fuel injectors 94 and the combustion chamber 38, provided that the axial distances 96 are not all the same between all of the combustion chamber arrangements 14, so that in one combustion chamber arrangement 14 a combustion instability frequency is produced which differs from the combustion instability frequency in the other combustion chamber arrangement 14.In further specific embodiments, the method can include the step of varying one or more axial lengths 80 of the cap arrangement 50, provided that the axial lengths 80 do not all correspond between all combustion chamber arrangements 14, so that in one combustion chamber arrangement 14 a combustion instability frequency is produced which differs from the combustion instability frequency in the other combustion chamber arrangement 14.

[0052] The ones relating to Fig.The various embodiments described and illustrated in Figures 1-12 can offer one or more of the following advantages over existing combustion chamber arrangements 14. In particular, the different axial distances 76, 96 and / or axial lengths 80, either alone or in various combinations, can decouple the combustion instability frequencies from the combustion dynamics. As a result, the various embodiments described herein can increase the thermodynamic efficiency, promote flame stability, and / or reduce undesirable emissions over a wide range of operating levels.

[0053] The present description uses examples to describe the invention, including the best mode, and also to enable any person skilled in the art to put the invention into practice, for example, to manufacture and use any devices and systems and to carry out any related processes. The patentable scope of the invention is defined by the claims and may include other examples that would occur to a person skilled in the art. Such other examples shall fall within the scope of the claims if they contain structural elements that do not differ from the wording of the claims or if they contain equivalent structural elements that differ only insignificantly from the literal content of the claims.

[0054] A system and method for reducing combustion dynamics comprises first and second combustion chamber assemblies grouped around an axis. Each combustion chamber assembly includes a cap assembly extending radially over the assembly and a combustion chamber located downstream of the cap assembly. Each cap assembly includes multiple tubes extending axially through the assembly to provide a flow connection from the cap assembly to the combustion chamber, and a fuel injector extending through each tube to provide a flow connection into each tube. Each cap assembly has an axial length, the axial length of which differs between the cap assembly in the first combustion chamber assembly and the cap assembly in the second combustion chamber assembly. Reference symbol list: 10 Gas turbine 12 Compressor section 14 combustion chamber arrangements 16 Turbine section 18" wheel 20 Generator 22 Working fluid 24 stationary guide vanes 26 rotating blades 28 compressor housings 30 Compressor outlet collection chamber 32 Combustion chamber housing 34 fuel nozzles 36 pipes 38 Combustion chamber 40 Transition channel 42 rotating blades 44 stationary guide apparatuses 46 End cover 48 Head end 50 cap arrangement 52 Combustion chamber wall 54 flow holes 56 Impact sleeve 58 circular tube bundles 60 central tube bundle 62 pie-shaped tube bundles 64 axial midline 66 central basic body 68 Coat 70 Ring channel 72 guide vanes 74 fuel supply openings 76 axial distances 78 axis 80 axial length of the cap arrangement 82 upstream area 84 downstream area 86 Pipe inlet 88 Pipe outlet 90 Fuel storage room 92 Fuel channel 94 Fuel injector 96 axial distance 100 axle 102 first resonant frequency 104 second resonant frequency 106 third resonant frequency

Claims

[1] System for reducing combustion dynamics in a gas turbine (10), the system comprising: a first and a second combustor assembly (14) arranged about an axis (78) of a rotor (18) of the gas turbine (10), each combustor assembly (14) having a cap assembly (50) extending radially across the combustor assembly (14) and a combustion chamber (38) arranged downstream of the cap assembly (50), the cap assembly (50) having an upstream surface (82) and a downstream surface (84) axially separated from the upstream surface (82) and defining an upstream end of the combustion chamber (38) of the respective combustor assembly (14); wherein each cap assembly (50) includes a plurality of tubes (36) extending axially through the cap assembly (50) to provide fluid communication through the cap assembly (50) to the combustion chamber (38), each tube (36) having a fuel injector (94) extending through each tube (36) to provide fluid communication into each tube (36); and wherein each cap assembly (50) has an axial length (80) defined between the upstream surface (82) and the downstream surface (84) of the respective cap assembly (50), wherein the axial length (80) of the cap assembly (50) in the first combustion chamber assembly (14) differs from the axial length (80) of the cap assembly (50) in the second combustion chamber assembly (14). [2] The system of claim 1, wherein the plurality of tubes (36) in each cap assembly (50) are grouped into a plurality of tube bundles (58, 62) arranged radially across the cap assembly (50), wherein the fuel injector (94) is arranged through each tube (36) at an axial distance (96) from the combustion chamber (38), and wherein the axial distance (96) is different for at least two tube bundles (58, 62) in the first combustion chamber assembly (14), and / or wherein each cap assembly (50) additionally includes a fuel nozzle (34) extending axially through the cap assembly (50) to provide fluid communication through the cap assembly (50) to the combustion chamber (38), each fuel nozzle (34) including: an axially extending central body (66), a shroud (68) surrounding at least a portion of the axially extending central body (66) surrounds several guide vanes (72),which extend radially between the central base body (66) and the shroud (68), a first fuel supply opening (74) through at least one of the plurality of guide vanes (72) at a first axial distance (76) from the combustion chamber (38), a second fuel supply opening (74) through the central base body (66) at a second axial distance (76) from the combustion chamber (38), and wherein the plurality of guide vanes (72) are arranged at a third axial distance (76) from the combustion chamber (38). [3] The system of claim 2, wherein at least one of the axial distances differs, whether the first axial distance (76) in the first combustion chamber assembly (50) is different from the first axial distance (76) in the second combustion chamber assembly (50), the second axial distance (76) in the first combustion chamber assembly (50) is different from the second axial distance (76) in the second combustion chamber assembly (50), or the third axial distance (76) in the first combustion chamber assembly (50) is different from the third axial distance (76) in the second combustion chamber assembly (50). [4] The system of claim 2, wherein at least two of the axial distances differ, whether the first axial distance (76) in the first combustion chamber assembly (14) is different from the first axial distance (76) in the second combustion chamber assembly (14), the second axial distance (76) in the first combustion chamber assembly (14) is different from the second axial distance (76) in the second combustion chamber assembly (14), or the third axial distance (76) in the first combustion chamber assembly (14) is different from the third axial distance (76) in the second combustion chamber assembly (14). [5] The system of claim 2, wherein the first axial distance (76) in the first combustion chamber assembly (14) is different from the first axial distance (76) in the second combustion chamber assembly (14), the second axial distance (76) in the first combustion chamber assembly (14) is different from the second axial distance (76) in the second combustion chamber assembly (14), and the third axial distance (76) in the first combustion chamber assembly (14) is different from the third axial distance (76) in the second combustion chamber assembly (14). [6] The system of claim 2, wherein each combustor assembly (14) includes a plurality of fuel nozzles (34), and wherein at least one of the first, second, or third axial spacings (76) is different for at least two fuel nozzles (34) in the first combustor assembly (14). [7] The system of claim 2, wherein each combustor assembly includes a plurality of fuel nozzles (34) and at least two of the axial distances, whether the first, second, or third axial distances (76), are different for at least two fuel nozzles (34) in the first combustor assembly (14). [8] The system of claim 2, wherein each combustor assembly (14) includes a plurality of fuel nozzles (34), and wherein the first, second, and third axial distances (76) are different for at least two fuel nozzles (34) in the first combustor assembly (14). [9] System for reducing combustion dynamics in a gas turbine (10), the system comprising: a first and a second combustor assembly (14) grouped about an axis (78) of a rotor (18) of the gas turbine (10), each combustor assembly (14) having a cap assembly (50) extending radially across the combustor assembly (14) and a combustion chamber disposed downstream of the cap assembly, the cap assembly (50) having an upstream surface (82) and a downstream surface (84) axially separated from the upstream surface (82) and defining an upstream end of the combustion chamber (38) of the respective combustor assembly (14); wherein each cap assembly (50) has a fuel nozzle (34) extending axially through the cap assembly (50) to provide fluid communication through the cap assembly (50) to the combustion chamber (38), wherein each fuel nozzle (34) includes: an axially extending central body (66), a shroud (68) surrounding at least a portion of the axially extending central body (66), a plurality of guide vanes (72) extending radially between the central body (66) and the shroud (68), a first fuel supply opening (74) through at least one of the plurality of guide vanes (72) at a first axial distance (76) from the combustion chamber (38), a second fuel supply opening (74) through the central body (66) at a second axial distance (76) from the combustion chamber (38), and wherein the plurality of guide vanes (72) are at a third axial distance (76) from the combustion chamber (38) are arranged,wherein the first, second and third distances (76) differ from each other; and, wherein each cap assembly (50) has an axial length (80) defined between the upstream surface (82) and the downstream surface (84) of the respective cap assembly (50), wherein the axial length (80) of the cap assembly (50) in the first combustion chamber assembly (14) differs from the axial length (80) of the cap assembly (50) in the second combustion chamber assembly (14).

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