JP2001289441A - Gas turbine combustor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a gas turbine combustor from combustion vibration. SOLUTION: A gas turbine combustor 1 comprises a flow guiding partition 113 arranged in a nozzle portion 3, which accommodates therein fuel nozzles 31 and 33 for feeding fuel into an inner cylinder 5 and an adjusting hole 115, which penetrates the flow guiding partition 113 so that a section 3b at the upstream side of the flow guiding partition communicate a with section 3a at the downstream side (inner cylinder side) thereof. As a result, it is possible to change the natural frequency of the combustor alone without changing the total length thereof because the volume of the upstream-side section 3b is added to that of the inner cylinder in which combustion is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas turbine combustor in which fuel is combusted by air pressurized by a compressor driven by a turbine to generate combustion gas for driving the turbine.

[0002]

2. Description of the Related Art In commercial and industrial gas turbines, there has been a recent strong demand for lowering pollution as well as higher output and higher efficiency, and reduction of NO _x (nitrogen oxide) in exhaust gas is a major issue. It has become. NO _X in the exhaust gas increases as the combustion temperature in the combustor is increased, for example, the combustion temperature is 16
When the temperature exceeds 00 ° C., it rapidly increases.

For this reason, in recent gas turbines, diffusion fuel
Reduce the rate of burning, perform premixed combustion,
So-called low NO_XType combustors are being used
You. Diffusion combustion injects fuel into the combustion air,
The mixture of fuel and air formed at the boundary with air
In order to burn, the air ratio (excess air ratio) in combustion is
Relatively high. Therefore, combustion is stable in diffusion combustion.
However, combustion temperature rises and NO_XLarge amount of
Become. On the other hand, premixed combustion is premixed with combustion air and fuel.
Aiki is formed, and this premixed gas is injected into the combustor to burn
Let it. In premixed combustion, compare the ratio of air volume to fuel volume
Air ratio in combustion (excess air)
Rate), so that the combustion temperature is reduced.
NO _XCan be reduced. Only
However, in premixed combustion, the air-fuel mixture becomes leaner as the air ratio increases.
As a result, combustion becomes unstable, causing problems such as blowout.
Easier to play. So, in the actual gas turbine combustor
Injects a relatively small amount of fuel into the combustor for diffusion combustion.
To form a stable pilot flame,
To ignite the premixture injected into the combustor
A stable premixed combustion flame is generated.

[0004]

However, in a gas turbine combustor mainly composed of premixed combustion, there is a problem that combustion oscillation is apt to occur. The combustion oscillation occurs when the combustion causes a pressure pulsation in the combustor, and the pulsation coincides with the natural frequency of the air column vibration of the combustor. When the combustion vibration occurs, the fluctuation range of the combustion pressure is amplified and the combustion becomes unstable, and low cycle vibration and noise due to the periodic fluctuation of the pressure of the combustor are generated.

[0005] The cause of the pulsation of the combustion pressure, which is the oscillating force of the combustion vibration, is likely to occur, for example, when the pilot flame becomes unstable or when the combustion speed of the premixed gas becomes excessive. For example, if the pilot flame becomes unstable, the ignition of the premixed gas injected into the combustor becomes unstable, so that the injected premixed gas repeats ignition and extinguishing, and intermittently intermittently occurs in the combustor. Combustion begins to occur. For this reason, periodic pressure fluctuations occur in the combustor, which easily develops into combustion oscillation.

The premixed gas injected into the combustor ignites while flowing toward the outlet in the combustor, burns over a certain period of time, becomes a combustion gas, and is discharged from the combustor outlet. However, in this case, if the supply speed of the premixed gas and the combustion speed match, the region where the combustion of the premixed gas occurs on the premixed gas flow path in the combustor is maintained almost constant and stable. A flaming flame is formed. However, when the combustion speed of the premixed gas becomes significantly higher than the premixed gas supply speed, the ignited premixed gas is instantaneously burned, and then a sufficient amount of the premixed gas is supplied into the combustor. Until the combustion stops. That is, if the combustion speed of the premixed gas becomes excessive, the supply of the premixed gas cannot catch up with the combustion, so that the combustion occurs intermittently in the combustor, which causes periodic pressure fluctuations and easily develops into combustion oscillation. Become.

Further, even if the intermittent combustion as described above does not occur, if the combustion speed of the premixed gas increases, the premixed gas after ignition ignites in a short time, and the premixed gas is burned during combustion. Since the flow distance in the combustor becomes short, combustion occurs in a narrow range in the flow direction of the premixed gas. When the premixed air is injected from a plurality of main nozzles, the combustion region of the premixed air from each of the main nozzles is concentrated in a narrow region in the axial direction of the combustor. In this case, heat is concentrated in a narrow combustion region, and the pressure of the combustion gas rapidly rises due to the temperature rise. Therefore, a large pressure wave (plane wave) is generated in the combustor, and the pressure in the combustor resonates and a periodic pressure is generated. Fluctuations may occur, and combustion oscillation is likely to occur.

In order to suppress combustion oscillation, it is necessary to prevent the generation of a pressure pulsation or a large pressure wave as an oscillating force, or to determine the frequency of the pressure fluctuation in the combustor and the characteristic of the air column vibration of the combustor. It is necessary to adjust the line length of the combustor so that the frequency does not match. However, it is difficult to prevent pressure pulsation and pressure waves from occurring in an actual gas turbine. Further, it is practically impossible to freely change the length of the pipeline of the combustor (combustor length) due to other restrictions. For this reason, a pressure pulsation near the combustor natural frequency may actually occur in the combustor.

In view of the above problems, an object of the present invention is to provide means capable of effectively suppressing the occurrence of combustion oscillation in a gas turbine combustor.

[0010]

According to the first aspect of the present invention, there is provided a gas for burning fuel by using combustion air pressurized by a turbine driven compressor to generate combustion gas for driving the turbine. A turbine combustor, comprising: a nozzle portion provided with a fuel nozzle; and an inner cylinder connected to the nozzle portion for burning fuel supplied from the nozzle portion. Combustion air is supplied to the nozzle portion and a fuel nozzle is provided. Is supplied into the inner cylinder from one end of the inner cylinder in a state of being mixed with fuel injected from the inner cylinder, and after burning in the inner cylinder, is supplied to the turbine as combustion gas from the other end of the inner cylinder. A gas turbine combustor is provided, comprising adjusting means capable of adjusting a natural frequency in vibration without changing a length of the gas turbine combustor.

That is, in the first aspect of the present invention, the natural frequency of the gas turbine combustor is changed so that the natural frequency of the combustor departs from the frequency of pressure pulsation in the combustor.
As described above, the natural frequency of the combustor can be changed by changing the length of the combustor as a pipeline. Also,
The line length of the combustor can also be changed by changing the actual length of the combustor. However, in practice, the length of the combustor cannot be freely changed due to other restrictions.
Therefore, in the present invention, an adjusting means for changing only the pipe length without changing the actual length of the combustor is provided.

As the adjusting means, for example, a position of a closed end (for example, a partition wall of a nozzle portion) inside the combustor is changed, and a pressure wave reflecting plate which reflects a pressure wave in a flow path of combustion air is disposed. Means can be used. According to the second aspect of the present invention, the nozzle portion includes a flow guide partition wall that deflects combustion air flowing into the nozzle portion from the outer periphery in the axial direction of the nozzle portion, and the adjusting unit includes the flow guide. 2. The gas turbine combustor according to claim 1, further comprising an adjustment hole provided on the upper side and communicating the insides of the nozzle portions on both sides of the flow guide partition with each other. 3.

That is, according to the second aspect of the present invention, the adjusting means is provided with an adjusting hole which penetrates the flow guide partition of the nozzle portion, and communicates with the inside of the nozzle portion on both sides of the flow guide partition. In the absence of a control hole, the flow guide partition forms the closed end of the combustor, from which the pressure waves generated in the combustor are reflected. However, by providing the adjustment hole in the flow guide partition, the section of the nozzle on the upstream side of the flow guide partition communicates with the inner cylinder. Thus, the section inside the nozzle portion on the upstream side of the flow guide partition functions as a volume chamber communicating with the closed end of the combustor through the adjustment hole, and the natural frequency of the combustor changes. Therefore, the natural frequency of the combustor changes without changing the outer length of the combustor.

According to the third aspect of the present invention, the adjusting means further includes a nozzle located on the side opposite to the inner cylinder with respect to the flow guide partition, among the sections in the nozzle section divided by the flow guide partition. 3. A gas turbine combustor according to claim 2 comprising means for adjusting the volume of an internal compartment. That is, in the invention of claim 3, the adjusting means includes, in addition to the adjusting hole provided in the flow guide partition, means for adjusting the volume of the inner section of the nozzle portion communicating with the inner cylinder side by the adjusting hole. This makes it possible to change the volume of the volume chamber (partition in the nozzle portion) communicating with the inner cylinder side, so that the natural frequency of the combustor can be adjusted in a wide range according to the actual frequency of the combustion pressure pulsation. Become.

According to the fourth aspect of the present invention, the combustion air passes through a combustion air passage provided on the outer periphery of the combustor.
2. The gas turbine combustor according to claim 1, wherein the gas turbine combustor according to claim 1, wherein the gas flows into the nozzle unit from a combustion air inlet provided in the nozzle unit, and the adjusting unit includes a pressure wave reflector disposed in the combustion air passage. 3. Provided. That is, in the invention of claim 4, a pressure wave reflector is provided in the combustion air passage. In a normal state without a pressure wave reflector, the combustion air inlet of the combustor is an open end due to air column vibration. In contrast, by providing the pressure wave reflector in the combustion air passage, the pressure wave reflector forms a closed end in air column vibration,
The vibration mode of the column vibration of the combustor changes, and the natural frequency of the combustor changes. For this reason, it is possible to change the natural frequency without changing the outer length of the combustor. The pressure wave reflection plate uses a perforated plate having a large number of through holes (for example, a so-called punching metal) or the like,
The pressure loss of the combustion air is prevented from increasing. Further, if the installation position of the pressure wave reflector is changed in the combustion air passage, the natural frequency of the combustor can be adjusted in a wide range according to the pulsation of the combustion pressure in the combustor. .

According to the fifth aspect of the present invention, the gas turbine combustion system according to the first aspect, wherein the adjusting means includes an annular volume chamber disposed around the inner cylinder and communicating with the inside of the inner cylinder. A vessel is provided. That is, in the invention of claim 5,
A volume chamber communicating with the inside of the inner cylinder is provided around the inner cylinder. As a result, the natural frequency of the combustor changes in the same manner as in the third aspect of the present invention, so that the natural frequency of the combustor can be changed without changing the outer length of the combustor.

According to a sixth aspect of the present invention, there is provided a gas turbine combustor which burns fuel by air pressurized by a compressor driven by a turbine to generate a combustion gas for driving the turbine. An inner cylinder connected to a combustion gas inlet of the turbine for burning supplied fuel and supplying the generated combustion gas to the turbine; and a pilot flame which is disposed at the center of the inner cylinder and injects fuel into the inner cylinder. And a pilot nozzle that is arranged around the pilot nozzle, injects a premixed air of air and fuel supplied from the compressor into the inner cylinder, and ignites by the pilot flame to generate a premixed flame. A plurality of main nozzles to be formed, and an expanded tube shape surrounding the pilot nozzle outlet and preventing a premixed gas from the main nozzle from igniting immediately near the main nozzle outlet. Comprising a Lee lots corn, and the pilot cone, to form a sound absorbing means for attenuating the reflection of the pressure wave in at least one of the inner wall surface on said inner cylinder,
A gas turbine combustor is provided.

According to the seventh aspect of the present invention, there is provided the gas turbine combustor according to the sixth aspect, wherein the sound absorbing means has an uneven portion formed over the entire inner wall surface. . According to an eighth aspect of the present invention, there is provided the gas turbine combustor according to the sixth aspect, wherein the sound absorbing unit includes a perforated plate that covers the entire inner wall surface.

That is, in the inventions of claims 6 to 8, the sound absorbing means is formed on at least one of the inner wall surfaces of the pilot cone and the inner cylinder. As the sound absorbing unit, for example, a unit that irregularly reflects a pressure wave on the inner wall surface of the pilot cone or the inner cylinder and attenuates the pressure wave by interference between the pressure waves is used. Therefore, as the sound absorbing means, irregularities having valleys and peaks along the axial direction of the inner cylinder are formed on the inner wall surface of the pilot cone or the inner cylinder (that is, when viewed from the cross section of the pilot cone or the inner cylinder, (The inner wall surface is formed to have wavy irregularities all around.)
Alternatively, the inner wall surface may be covered with a perforated plate over the entire circumference. As a result, the pressure wave is irregularly reflected on the pilot cone or the inner wall surface of the inner cylinder and is attenuated by mutual interference, so that the excitation force of the combustion vibration is reduced.

[0020]

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, the configuration of a general gas turbine combustor will be described with reference to FIG. FIG. 1 is a sectional view illustrating a schematic configuration of a gas turbine combustor.

In FIG. 1, reference numeral 1 denotes the entire combustor. The combustor 1 includes an inner cylinder 5 and a nozzle unit 3 provided with a nozzle for injecting fuel into the inner cylinder 5. The inner cylinder 5 of the present embodiment has a one-piece structure in which an inner cylinder portion 5b as a combustion chamber for burning injected fuel and a transition piece portion 5a for guiding combustion gas generated by combustion to a turbine inlet are integrally formed. Have been. The combustor 1 is held in the turbine casing 7 by a support (not shown).
In an actual gas turbine, a plurality of combustors shown in FIG. 1 are arranged on a circumference at equal intervals, and each supplies a combustion gas to the turbine.

The combustion air 11 is pressurized from the atmosphere by a turbine-driven gas turbine compressor (not shown) and supplied into the casing 7. The gas turbine combustor 1 is attached to a cylindrical combustor attachment portion (referred to as a top hat) 71 provided in a casing 7, and the combustion air 11 flows from the inside of the casing 7 to the inner wall of the top hat 71 and the nozzle portion 3. The fuel gas passes through a combustion air passage 73 formed by an annular space between the outer periphery and a combustion air inlet 35 provided in the nozzle portion 3 of the combustor combustor 1 and flows into the nozzle portion 3.
A flow guide 1 to be described later, which guides the inflowing combustion air in the axial direction of the inner cylinder, is provided at the combustion air inlet 35 of the nozzle portion 3.
13 are provided. The combustion air that has flowed into the nozzle portion 3 is injected from the nozzle portion 3 into the inner cylinder 5 through the pilot nozzle 31 and the main nozzle 33.

The nozzle portion 3 has a configuration in which a pilot nozzle 31 is arranged at a central portion in a cylindrical shell, and a plurality of (eight in the present embodiment) main nozzles 33 are arranged around the pilot nozzle 31 at equal intervals. Pilot nozzle 31
Is a pilot fuel nozzle 3 for injecting fuel into the inner cylinder 5.
1a, the injected fuel is ignited by an igniter (not shown), and diffused combustion is performed while mixing with the combustion air flowing through the pilot nozzle 31 from the combustion air inlet 35 in the inner cylinder 5 to form a pilot flame. I do.

The main nozzle 33 is a premix nozzle, and injects fuel from the fuel nozzle 33a into the combustion air supplied to the nozzle section 3 from the combustion air inlet 35 to form a premix gas to form the inner cylinder 5b. Spray. Reference numeral 37 in FIG. 1 denotes swirler vanes radially arranged around the fuel nozzle 33a in the main nozzle 33. Swirl vane 3
Numeral 7 is a vane having a blade shape arranged at an angle in the flow direction so as to impart a swirling speed component to the combustion air flow flowing through the main nozzle 33. Swirl vane 3
The combustion air that has passed through 7 generates a swirling flow in the main nozzle 33. Fuel (a gas fuel such as city gas or natural gas or a liquid fuel such as heavy oil is used in the present embodiment) is supplied from a fuel injection hole (not shown) provided on the downstream side of the swirler vane 37 of the fuel nozzle 33a. It is injected into the swirling flow of the combustion air. Therefore, mixing of the injected fuel and combustion air is promoted, and a uniform premixed air is formed in the main nozzle 33.

An expanded pipe-shaped pilot cone 36 is provided at the outlet of the pilot nozzle 31. The pilot cone 36 prevents the pilot flame generated by the pilot nozzle 31 from coming into contact with the premixed air injected from the main nozzle 33 at a position immediately adjacent to the main nozzle 33, so that the premixed air near the main nozzle outlet is prevented. To prevent backfire into the main nozzle due to ignition.

At the outlet of the main nozzle 33, a premixed gas injected from the main nozzle is filled with a pilot cone 36.
In order to prevent turbulence due to collision with the side surface, a nozzle extension pipe 34 for guiding the premixed gas injected from the main nozzle along the side surface of the pilot cone 36 is connected. An air bypass valve is shown at 9 in FIG. The air bypass valve 9 is a gate valve that directly connects the tail tube portion 5a of the inner cylinder 5 to the inside of the casing 7, and has a function of controlling the amount of combustion air flowing into the inner cylinder 5 from the nozzle portion 3 according to the load. For example, when the amount of combustion air to be supplied from the nozzle unit 3 to the inner cylinder 5 is small at the time of starting the gas turbine or at a light load, the air bypass valve 9 is opened by an actuator (not shown), and the combustion in the casing 7 is stopped. Part of the air is introduced directly into the transition piece 5a without passing through the nozzle section 3. As a result, the amount of combustion air flowing from the combustion air inlet 35 of the nozzle portion 3 decreases, and it becomes possible to form an appropriate premixed air in the main nozzle 33.

The premixed gas injected around the pilot cone 34 from the main nozzle 33 through the extension pipe 34 comes into contact with the pilot flame generated by the pilot nozzle 31 at the peripheral edge of the pilot cone 36 outlet.
A premixed flame is generated at a position sufficiently distant from the main nozzle 33 outlet. The combustion gas generated by the premixed flame is
The turbine is supplied to the turbine through a turbine inlet stationary blade (not shown) connected to the outlet 52 of the tail tube 5a, and drives the turbine.

In this embodiment, the combustor 1 is provided with a cooling passage through which a cooling fluid for cooling the wall surface flows. That is, in the present embodiment, the inner cylinder 5b and the tail cylinder 5a of the inner cylinder 5 have a double wall structure, and a gap that functions as a cooling steam passage is formed between the thin inner wall and the outer wall. ing. Further, in the present embodiment, a cooling steam inlet pipe 507 communicating with the cooling passage is provided at a position corresponding to the vicinity of the boundary between the inner cylinder 5b and the tail cylinder 5a. After flowing into the cooling passage from the inlet pipe 507, the cooling steam flows in the wall of the inner cylinder 5b toward the upstream side (main nozzle side) and flows in the transition piece 5a toward the downstream side (turbine inlet side). After convection cooling the inner walls of the inner cylinder 5b and the tail cylinder 5a, the outlet pipe 5 is provided at the upstream end of the inner cylinder 5b.
09a and the outlet pipe 509b provided at the downstream end of the transition piece 5b.

Next, prevention of combustion vibration of the gas turbine combustor according to the present invention will be described. As described above, when the frequency of the pressure pulsation generated in the gas turbine combustor and the natural frequency of the air column vibration of the combustor 1 are close to each other, large combustion vibration is likely to occur. To prevent this, it is necessary to make the natural frequency of the combustor sufficiently far from the frequency of the pressure pulsation in the combustor, or to reduce the pressure pulsation in the combustor. There is. Usually, in order to change the natural frequency of the combustor, it is necessary to change the size (total length) of the combustor. However, in practice, it is impossible to freely set the total length of the combustor due to restrictions on arrangement in the casing. Can not. Therefore, in the embodiment described below, the natural frequency of the combustor is changed without changing the overall length of the combustor, and the interval between the frequency of pressure fluctuation in the combustor and the natural frequency of the combustor is increased. Is possible.

(1) First Embodiment In this embodiment, the natural frequency of the entire combustor 1 is changed by providing an adjustment hole that penetrates the flow guide 113 provided in the nozzle portion 3. FIG. 2 is an enlarged cross-sectional view of the nozzle 3 in the gas turbine combustor of the present embodiment. The flow guide 113 includes a guide plate 113a provided at an edge of the combustion air inlet 35 of the nozzle portion, and a guide partition 113b provided at a position facing the guide plate 113a in the nozzle portion 3. The guide partition 113b is a partition extending from the guide support 113c supported at the center of the nozzle unit 3 by a support (not shown) toward the outer periphery of the nozzle unit. Flow guide 113
It has a function of turning the combustion air flowing outside the nozzle portion 3 through the combustion air passage 73 by 180 degrees and smoothly flowing the inside of the nozzle portion 3 toward the inner cylinder. Usually, guide partition 1
13b, the inside of the nozzle portion 3 is divided into an inner cylinder side section 3a and a section 3a.
And an upstream section 3b isolated from the upstream section 3b. Therefore, in a normal combustor, the guide partition 113 serves as a closed end of the combustor, and the pressure wave generated by the combustion in the inner cylinder 5 is reflected by the guide partition 113a. Also, the combustion gas outlet 52 (FIG. 1) of the inner cylinder 5 becomes the open end of the combustor, and the primary partition vibrates the guide partition 113 (closed end) as a node.
A standing wave having an antinode at the inner cylinder outlet 52 (open end) is generated,
The natural frequency is determined by the pipe length and the pipe diameter between the open end and the closed end.

In this embodiment, by providing an adjusting hole 115 (FIG. 2) penetrating the guide partition 113a, the upstream section 3b and the inner cylinder section 3a are communicated with each other to change the natural frequency of the combustor. ing. By making the upstream section 3b communicate with the inner cylinder side section 3a, the closed end becomes the upstream section 3b.
b, and the volume of the upstream section 3b is added to the inner cylinder section 3a, so that the natural frequency of the entire combustor is lower than when the adjusting hole 115 is not provided. For this reason, it is possible to change the natural frequency without changing the overall length of the combustor. In addition, the flow guide partition 113
Since the natural frequency also changes depending on the diameter, number, and arrangement of the adjustment holes 115 on b, it is preferable that the details of the diameter, number, and arrangement of the adjustment holes 115 be determined by an experiment using an actual combustor.

In this embodiment, in addition to the above, FIG.
As shown in the figure, a second partition wall 117 whose position in the axial direction can be changed is provided in the upstream section 3b of the nozzle section 3. The partition wall 117 has a combustor cover 1 at the end of the nozzle portion 3.
It can be fixed at an arbitrary position in the axial direction within the nineteen concave portion 119a by an appropriate means. By moving the second partition 117 in the axial direction, the flow guide partition 113 is moved.
As the distance between a and the second partition 117 changes, the volume of the upstream section 3b itself also changes. For this reason, in the present embodiment, the adjustment hole 11 on the flow guide partition 113a is formed.
The natural frequency of the combustor 1 can be adjusted in a wide range by changing the axial position of the second partition 117 in addition to the number, arrangement, and the like of the five. (2) Second Embodiment Next, a second embodiment of the present invention will be described.

In the first embodiment described above, the control holes 11 provided in the flow guide partition 113b in the combustor nozzle 3 are provided.
5 and the second partition 117 adjust the natural frequency of the combustor. However, in the present embodiment, the first embodiment differs from the first embodiment in that a natural frequency adjusting means is provided outside the combustor 1. Are different. FIG. 3 is a cross-sectional view similar to FIG. 2 illustrating the schematic configuration of the present embodiment.

As shown in FIG. 3, in this embodiment, the reflector 81 is disposed in the combustion air passage 73 formed between the top hat 71 of the casing 7 and the outer periphery of the combustor 1 so that the combustor 1 has a unique shape. The frequency is changed. Reflector 7
Reference numeral 3 denotes an annular porous plate having a large number of through holes 81a so as not to obstruct the flow of the combustion air in the combustion air passage 73, and is fixed to the inner wall of the top hat at an outer periphery thereof by using an appropriate means. Normally, a pressure wave propagating from the inside of the nozzle portion 3 to the combustion air passage 73 is transmitted from the combustion air passage 73 into the casing 7. Therefore, when there is no reflector 81, the entrance of the combustion air passage 73 forms an antinode of air column vibration. On the other hand, in the present embodiment, since the reflecting plate 81 is provided in the middle of the combustion air passage 73, the pressure wave propagating from inside the nozzle unit 3 is reflected by the reflecting plate 81. Accordingly, the position of the reflector 81 forms a node of the air column vibration, and the natural frequency of the air column vibration generated by the combustor 1 and the combustion air passage 73 changes.

The reflecting plate 81 can be fixed at an arbitrary axial position of the combustion air passage 73.
According to the present embodiment as well, it is possible to adjust the natural frequency of the combustor 1 in a wide range. (3) Third Embodiment In the present embodiment, the natural frequency of the combustor is adjusted by adding a volume chamber communicating with the inside of the inner cylinder to the outer periphery of the inner cylinder 5.

FIG. 4 is a sectional view similar to FIG. 1 for explaining the structure of the present embodiment. In the present embodiment, a hollow ring 91 is fixed to the outer periphery of the transition piece 5a of the inner cylinder 5 by brazing or the like. The internal space (volume chamber) 91a of the ring 91 communicates with the inside of the transition piece 5b via a communication hole 92 provided on the outer periphery of the transition piece 5a. Thereby, the volume chamber 91a is added to the inner cylinder 5 through the communication hole 92, and the natural frequency of the combustor 1 is reduced as compared with the case where the volume chamber 91a is not provided.

In FIG. 4, the ring 91 (volume chamber 91)
a) is provided on the outer periphery of the transition piece 5a portion of the inner cylinder 5, but by providing the ring 91 on the outer periphery of the portion where the air column vibration node is formed in the inner cylinder 5, the combustion vibration can be effectively prevented. Can be prevented. In the above-described first to third embodiments, the generation of combustion vibration is prevented by setting the natural frequency of the combustor 1 at a position away from the frequency of pressure fluctuation in the combustor in advance. . On the other hand, in the following embodiments, the generation of combustion vibration is prevented by attenuating the pressure wave generated by the combustion in the combustor to reduce the excitation force of the combustion vibration. (4) Fourth Embodiment In the present embodiment, a sound absorbing means for attenuating a pressure wave generated by combustion in the inner cylinder 5 is provided on at least one of the inner wall surface of the pilot cone 36 or the inner cylinder 5 of the combustor 1. In addition, the vibrating force of combustion vibration is reduced.

FIG. 5 is a sectional view similar to FIG. 1 showing the structure of this embodiment. As shown in FIG. 5, in the present embodiment, sound absorbing means 36d and 5d are provided on the inner wall surface 36a of the pilot cone 36 and the inner wall surface 5c of the inner cylinder 5, respectively. FIG. 6 is a diagram schematically showing the shape of the sound absorbing means 5d provided on the inner wall surface 5c of the inner cylinder 5 part. As shown in FIG. 6, in the present embodiment, valley portions 501d and crest portions 502d are alternately provided along the inner cylinder axis direction on the inner wall surface 5c of the inner cylinder 5 over the entire circumference. The inner wall surface 5c has a corrugated uneven shape in a cross section taken on a plane perpendicular to the axis of. Although not shown, the sound absorbing means 36d on the inner wall surface 36a of the pilot cone 36 also has the same wave-like irregularities as the inner wall surface 5c of the inner cylinder. As described above, by forming the irregularities on the surfaces of the inner wall surfaces 36a and 5c, the pressure wave generated by the combustion is reflected in different directions at the valley 501d and the peak 502d. The pressure waves attenuate due to mutual interference. For this reason, the vibration generating force is reduced, and the occurrence of large combustion vibration is prevented.

The shape of the sound absorbing means 36d and 5c formed on the inner wall surfaces 36a and 5c need not be limited to a waveform as long as the pressure wave is irregularly reflected and attenuated by interference. Pilot cone 36 and inner cylinder 5
May be covered. Further, in the present embodiment, the sound absorbing means is provided on both the pilot cone 36 and the inner wall surface of the inner cylinder 5. However, one of the inner wall surface of the pilot cone 36 and the inner wall surface of the inner cylinder 5 has an uneven shape. It has been found that even when the sound absorbing means is provided, combustion vibration is less likely to occur.

[0040]

According to the invention described in each of the claims, a common effect is obtained in which combustion oscillation in the gas turbine combustor can be effectively prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a general schematic configuration of a gas turbine combustor.

FIG. 2 is a diagram illustrating a first embodiment of the present invention.

FIG. 3 is a diagram illustrating a second embodiment of the present invention.

FIG. 4 is a diagram illustrating a third embodiment of the present invention.

FIG. 5 is a diagram illustrating a fourth embodiment of the present invention.

FIG. 6 is a diagram illustrating details of a configuration according to a fourth embodiment;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Gas turbine combustor 3 ... Nozzle part 5 ... Inner cylinder 35 ... Combustion air inlet 113 ... Flow guide 113b ... Flow guide partition wall 115 ... Adjustment hole

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Junji Hashimura 2-1-1 Shinama, Araimachi, Takasago City, Hyogo Prefecture Inside the Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor Mitsuru Inada 2-1-1 Shinama, Araimachi Takasago City, Hyogo Prefecture No. 1 Inside the Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor Shigetomi Bandai 2-1-1, Araimachi, Araimachi, Takasago City, Hyogo Prefecture Inside the Takasago Research Institute, Mitsubishi Heavy Industries, Ltd. No. 1-1 Inside Mitsubishi Heavy Industries, Ltd. Takasago Works (72) Inventor Hiroaki Ochiai 2-1-1, Araimachi Shinhama, Takasago City, Hyogo Prefecture Inside Mitsubishi Heavy Industries, Ltd. Takasago Works

Claims (8)

[Claims] 1. A gas turbine combustor for combusting fuel using combustion air pressurized by a turbine-driven compressor to generate combustion gas for driving the turbine, wherein a fuel nozzle is disposed. And an inner cylinder connected to the nozzle portion for burning fuel supplied from the nozzle portion, wherein the combustion air is mixed with fuel supplied to the nozzle portion and injected from the fuel nozzle, and one end of the inner cylinder is provided. After combustion in the inner cylinder, and then supplied to the turbine as combustion gas from the other end of the inner cylinder.Furthermore, the natural frequency of the air column vibration of the combustor and the length of the gas turbine combustor are changed A gas turbine combustor comprising adjusting means that can be adjusted without performing. 2. The nozzle unit includes a flow guide partition for deflecting combustion air flowing from an outer periphery of the nozzle unit in the axial direction of the nozzle unit, and the adjusting unit is provided on the flow guide, 2. The gas turbine combustor according to claim 1, further comprising an adjustment hole that allows the insides of the nozzle portions on both sides of the partition to communicate with each other. 3. The adjusting means further comprises a means for adjusting a volume of a section in the nozzle portion, which is located on a side opposite to the inner cylinder with respect to the flow guide partition, among the sections in the nozzle section divided by the flow guide partition. The gas turbine combustor according to claim 2, comprising: 4. The combustion air passes through a combustion air passage provided on an outer periphery of a combustor and flows into a nozzle from a combustion air inlet provided in the nozzle. With a pressure wave reflector arranged at
The gas turbine combustor according to claim 1. 5. The gas turbine combustor according to claim 1, wherein the adjusting means includes an annular volume chamber disposed around the inner cylinder and communicating with the inside of the inner cylinder. 6. A gas turbine combustor for burning fuel by air pressurized by a compressor driven by a turbine to generate combustion gas for driving the turbine, the gas turbine combustor being connected to a combustion gas inlet of the turbine, An inner cylinder that burns the supplied fuel and supplies the generated combustion gas to the turbine; a pilot nozzle that is arranged at the center of the inner cylinder and injects fuel into the inner cylinder to form a pilot flame; A plurality of main nozzles arranged around a nozzle, injecting a premixed air of air and fuel supplied from the compressor into an inner cylinder, and ignited by the pilot flame to form a premixed flame; A pipe-shaped pilot cone surrounding the pilot nozzle outlet and preventing the premixed gas from the main nozzle from igniting immediately near the main nozzle outlet. Wherein the pilot cone, to form a sound absorbing means for attenuating the reflection of the pressure wave on at least one inner wall surface of the inner cylinder, the gas turbine combustor. 7. The gas turbine combustor according to claim 6, wherein said sound absorbing means has an uneven portion formed over the entire inner wall surface. 8. The gas turbine combustor according to claim 6, wherein said sound absorbing means includes a perforated plate covering said inner wall surface over the entire circumference.