JPH11223342A - Combustor for gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a combustor for gas turbine in which a flame can be formed more stably by reducing formation of shearing layer flame thereby suppressing interference with an adjacent flame sufficiently. SOLUTION: The combustor for gas turbine comprises a diffuse combustion burner 2 disposed in the center of a combustor, and an annular premixed combustion burner 10 disposed around the diffuse combustion burner. A conical tubular inner barrier wall 6A having burner outlet cross-section enlarging toward downstream is disposed at the outlet of the diffuse combustion burner 2 while a conical tubular outer barrier wall 6B having burner outlet cross-section enlarging toward downstream is disposed at the outlet of the premixed combustion burner 10 and the inner and outer barrier walls are jointed at the forward end on the downstream side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a combustor for a gas turbine, and more particularly, a diffusion combustion burner is installed at a central portion of the combustor, and a premix combustion burner is installed around the periphery of the diffusion combustion burner. The present invention relates to a gas turbine combustor.

[0002]

2. Description of the Related Art In recent combined cycle power plants, the inlet temperature of a gas turbine is increased to increase the efficiency. Increasing the inlet temperature leads to an increase in the amount of exhausted nitrogen oxides (hereinafter referred to as NOx). On the other hand, there is a great demand for reducing NOx in exhaust gas, and various measures have been taken to reduce NOx. I have.

In general, NOx generated in a gas turbine combustor using a fuel having a low nitrogen content is thermal NOx generated by oxidizing nitrogen in air. Since the generation of thermal NOx is highly temperature-dependent, it is effective to lower the flame temperature in the combustor as a method for reducing NOx in the combustor for a gas turbine.

[0004] The combustion system mainly includes diffusion combustion and premix combustion. Diffusion combustion is excellent in flame stability and can form a flame in a wide fuel-air ratio range.However, since fuel and air are mixed and burned, the fuel-air ratio spatially changes significantly in the flame,
Even if lean combustion is attempted, part of the fuel burns in a state of excess fuel. Therefore, a large amount of NOx is likely to be generated due to a local increase in the flame temperature.

On the other hand, in premixed combustion, fuel and air are mixed before being charged into a combustion chamber. Therefore, in this combustion method, the fuel-air ratio in the flame can be more easily made uniform than in the diffusion combustion, and the formation of a local high-temperature portion due to uneven mixing can be avoided, so that the NOx reduction effect is large. However, the conditions of the fuel-air ratio and the fuel injection speed at which the flame can be formed stably are narrower than those of the diffusion combustion, and it is difficult to adjust them.

At present, two-stage combustion combining diffusion and premixing is widely used as a method for suppressing the rise in combustion temperature and suppressing the generation of NOx while ensuring flame stability. In this two-stage combustion system, diffusion combustion is performed as the first stage combustion in order to favor ignition and flame holding, and premixed combustion having a large NOx reduction effect is performed in the second stage combustion. A method of maintaining flame stability while reducing NOx has been used.

[0007] For example, in the combustor disclosed in Japanese Patent Application Laid-Open No. 7-280267, a diffusion combustion burner is disposed at the center of the combustor, and an annular premixed combustor is formed around the burner. I have. In addition, Japanese Patent Application Laid-Open No. 6-241
At 457, a diffusion combustion burner is located at the center of the combustor, around which a plurality of cylindrical premix combustion burners are formed. In these two types of combustors, ie, combustors that perform two-stage combustion, the fuel-air ratio of the diffusion flame formed at the center is made as low as possible to reduce NOx, and the combustion ratio of the premixed flame is increased to reduce the NOx. It is trying to make it.

[0008]

Due to the severe environmental problems in recent years, gas turbines have been required to further reduce NOx. A combustor combining this diffusion combustion and premix combustion, and further having a flame temperature In order to reduce the premixed combustion, the ratio of the premixed combustion is increased, and the premixed ratio is also increased, so that the premixed combustion is performed in a leaner state. However, when the proportion of premixed combustion is increased to reduce NOx, the flame becomes unstable as described above, which is a major problem. In addition, this kind of combustion combining diffusion combustion and premixed combustion is considered. In a vessel, the relationship between the two combustion flames is likely to be unstable and combustion vibration may be generated.

The conditions for generating the combustion oscillation are extremely complicated, and there are cases where the conditions for ejecting the fuel for diffusion combustion and the premixed gas, and the supply ratio of the fuel for diffusion combustion and the fuel for premixed combustion are changed. When the conditions are reached, the flame becomes unstable and combustion oscillations occur. In particular, in a combustor provided with a plurality of combustion burners, there is a problem of generation of combustion oscillation due to interference between the diffusion combustion flame and the premixed combustion flame.

That is, in the combustor in which the diffusion combustion burner and the premix combustion burner are combined, as shown in FIG. 10, a diffusion flame is stably formed at the center of the combustor by swirling, and As a method of forming a lean premixed flame on the outer periphery, a conical partition is provided at the outlet of the diffusion combustion burner and a partition is provided between the flame and the premixed combustion burner provided on the outer periphery.

[0011] Since the diffusion combustion burner needs to propagate the flame to the premix burner on the outer periphery thereof at the time of load switching or the like,
A circulation flow is formed by swirling downstream of the diffusion combustion burner,
A conical partition wall is often used as a structure for stabilizing the diffusion flame and facilitating the propagation of the flame to the premix burner to the outer periphery. The premixed combustion burner holds the flame by a flame stabilizer provided downstream or by a circulation vortex formed downstream of the premixer by swirling given to the premixed gas.

When a conical partition is disposed at the outlet of the diffusion combustion burner, a vortex starting from the partition tip is formed downstream of the partition tip, so that the unburned diffusion fuel and the unburned premixed gas are mixed with each other. Creates a shear layer flame using this vortex as a flame holding point. Since this shear layer flame is unstable and is formed from unburned diffusion fuel, it has a higher fuel-to-air ratio than the premixed flame formed on its outer periphery, and thus tends to be a flame holding point for unburned premixed gas. For this reason, it becomes a factor of flame instability due to flame interference and combustion oscillation is easily generated.

When developing a combustor that further reduces NOx from the conventional combustor, it is essential to increase the premixed combustion ratio. However, if the premixed combustion ratio is increased, the premixed flame becomes stable. Therefore, it is necessary to reduce the factors causing the above-mentioned combustion oscillation as much as possible. Also, reduction of combustion oscillation is very important because it directly affects both the operability and reliability of gas turbine combustors, and is an important issue in the development of gas turbine combustors. is there.

The present invention has been made in view of the above, and an object of the present invention is to reduce the formation of a shear layer flame and reduce the interference of adjacent flames even when aiming for a lower NOx emission concentration. An object of the present invention is to provide a gas turbine combustor of this type that can reduce the temperature sufficiently and form a more stable flame.

[0015]

That is, the present invention provides a gas turbine combustor in which a diffusion combustion burner is installed at the center of a combustor, and an annular premix combustion burner is installed around the periphery of the diffusion combustion burner. In the outlet portion of the diffusion combustion burner, a conical cylindrical inner partition wall whose burner outlet cross-sectional area increases toward the downstream is provided, and at the outlet of the premixed combustion burner, the burner outlet cross-sectional area is toward the downstream. An expanding conical cylindrical outer partition is provided, and the downstream end of the inner and outer partition is formed so as to be joined to achieve an intended purpose.

The present invention also provides a gas turbine combustor in which a diffusion combustion burner is installed at the center of the combustor and an annular premix combustion burner is installed around the periphery of the diffusion combustion burner. At the outlet portion, a burner outlet cross-sectional area is provided with a conical cylindrical inner partition wall which increases toward the downstream, and on the inner peripheral side of the outlet of the premixed combustion burner, a conical cylindrical shape whose diameter decreases toward the downstream. An outer partition is provided, the downstream end portions of the two partitions are joined, and a cooling air ejection hole for cooling the partition is provided in one or both of the inner and outer partitions.

[0017] A diffusion combustion burner is provided at the center of the combustor, and a premix combustion burner is provided on the outer periphery of the diffusion burner. The premix combustion burner surrounds the diffusion combustion burner. In a gas turbine combustor formed by juxtaposition of a plurality of cylindrical burners, at the outlet of the diffusion combustion burner, a burner outlet cross-sectional area is provided with a conical cylindrical inner partition wall that expands downstream, At the outlet of the premixed combustion burner, on the side of the diffusion combustion burner, a conical cylindrical outer partition wall whose diameter decreases toward the downstream is provided, and the downstream end portions of both the partition walls are joined, and In one or both of the partition walls, a cooling air ejection hole for cooling each partition wall is provided.

In this case, the cooling air ejection hole has a lip structure in which the cooling air is ejected downstream along the partition wall surface. Further, a swirling blade for generating a swirling premixed airflow is provided downstream of the premixed combustion burner.

That is, in the combustor for the turbine formed as described above, the conical cylindrical inner partition wall whose cross-sectional area of the burner outlet increases toward the downstream is provided at the outlet of the diffusion combustion burner, and the premixing is performed. At the outlet portion of the combustion burner, a conical cylindrical outer partition wall having a burner outlet cross-sectional area expanding toward the downstream is provided, and the downstream end portions of the inner and outer partition walls are formed so as to be joined to each other, so that the diffusion is prevented. The tip of the partition wall at the outlet of the combustion burner is moved to a position away from the premixed combustion burner (on the side of the central axis), and the shear layer flame near the premixed combustion burner, which has been concentrated conventionally, is scattered to reduce the interference of adjacent flames. It is possible to reduce the temperature sufficiently and form a stable flame.

That is, the premixed combustion burner holds flame by a flame stabilizer originally provided downstream or by a circulation vortex formed downstream of the premixer by a swirl given to the premixed gas. When the partition wall is arranged only at the outlet of the diffusion combustion burner as in the conventional case, a vortex is generated downstream of the tip of the partition wall, and the vortex is defined as a flame holding point by the unburned diffusion fuel and the unburned premixed gas. A shear layer flame is formed. The shear layer flame formed between the diffusion flame and the premixed flame is not only unstable but also formed from unburned diffusion fuel, and therefore has a higher fuel-air ratio than the premixed flame formed on the outer periphery thereof. It is easy to become a flame holding point for the premixed fuel. For this reason, it becomes a factor of flame instability due to flame interference and combustion oscillation is easily generated. In this regard, as in the present invention, the influence of the shear layer flame on the premixed combustion flame can be suppressed by moving the tip of the partition wall away from the premixed combustion burner side.

Further, in the present invention, since the cooling air ejection holes are provided in the inner and outer partitions so that the cooling air flows along the surface of the partitions, generation of vortices from the stagnation region formed by the partitions can be suppressed. Therefore, it is possible to prevent the shear layer flame formed at the tip of the partition wall from moving due to the vortex. In addition, since the air flowing along the partition walls at both the burner outlets for diffusion and premixing has the effect of rectifying the partition wall surface and also rectifying the flow downstream of the partition junction,
By reducing the vortex serving as a flame holding point of the shear layer flame formed downstream of the partition wall joint, the effect of not forming this shear layer flame clearly is obtained.

This is due to the synergistic effect of the effect of separating the shear layer flame from the premixed flame by the partition walls at the outlets of both the diffusion and premix burners and the effect of weakening the shear layer flame by the air flowing on the partition surface. This makes it possible to prevent instability of the flame and reduce combustion oscillation.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. 1 and 2 show a main part of the gas turbine combustor, and FIG. 3 schematically shows the air system. A gas turbine is provided with a plurality of cans, and these figures show one of the cans. The gas turbine includes an air compressor 24, a combustor 26, and a turbine 25, as shown in FIG.

The air 23 from the air compressor 24 is introduced into a combustor 26, where it burns fuel and becomes a high-temperature gas, which is guided to a turbine 25. The combustor 26 includes a combustion chamber 1, a diffusion combustion burner 2, and a plurality of premix burners 10. The combustion air 23 from the air compressor 24 is
The surface of the liner is cooled from the outer periphery downstream of the liner forming the combustor and guided to the combustor upstream. The air 23 is supplied to the combustor 26 as part of the diffusion fuel dispersion air 7, the film air 18 from the partition walls, and the premixed gas 21. The fuel is supplied from the fuel nozzle 3 for diffusion combustion and the fuel nozzle 11 for premix combustion.

The diffusion combustion burner 2 comprises a diffusion combustion fuel nozzle 3, swirling blades 5 and partition walls 6, and is installed at the center of the combustor. An annular premix burner 10 is arranged on the outer periphery of the diffusion combustion burner 2. The partition wall 6 has a conical partition wall 6A that increases the cross-sectional area of the diffusion combustion burner outlet toward the downstream, and a conical partition wall that increases the annular cross-sectional area of the premixed combustion burner outlet toward the diffusion combustion burner side. 6B
And a structure combining the above.

In the present embodiment, the partition wall on the premixed combustion burner side also has a structure integral with the diffusion combustion burner 2 for ease of decomposition and the like. The conical partition wall that expands toward the diffusion side is referred to as a diffusion-side partition wall 6A, and the conical partition wall whose cross-sectional area of the annular premix burner outlet expands toward the diffusion combustion burner side is referred to as a premix-side partition wall 6B. .

The fuel for diffusion combustion is ejected as a swirling flow from a fuel ejection hole 4 provided at the tip of the diffusion fuel nozzle 3.
At the same time, the diffusion fuel dispersing air 7 swirled by the swirling blades 5 is ejected from the outer periphery, and both the fuel and the air are swirled and ejected into the combustion chamber 1. Since the fuel and the air are swirled together, the momentum of the swirl can be secured, and a circulation flow 8 is formed downstream of the diffusion-side partition 6A, where the flame is stably held as a diffusion flame 9.

The annular premixed combustion burner 10 installed on the outer periphery of the combustor includes a premixed combustion fuel nozzle 11, fuel supplied from the premixed combustion fuel nozzle 11, and air introduced from the burner inlet. , And an annular flame holding ring 13 installed at the outlet of the premix combustion burner. The fuel and air for the premixed flame are mixed into the premixing section 12 and then charged into the combustion chamber 1. A circulating flow 14 is formed downstream of the flame holding ring 13 at the burner outlet. During the premix combustion, the circulating flow 14 becomes a high-temperature combustion gas, and the premixed flame 15 is stabilized by the combustion gas.

The diffusion combustion burner 2 has a diffusion combustion burner outlet installed upstream of the flame holder 13 at the premix burner outlet in consideration of flame propagation from the diffusion flame to the premixed flame 15.

FIG. 4 shows the detailed structure of the partition walls 6A and 6B installed between the diffusion combustion fuel nozzle 3 and the premix combustion burner 10. The inner partition wall 6A and the outer partition wall 6B are formed such that their downstream end portions are joined. In this case, the shape of the joint tip is as small as possible so that the flame can be fixed to the tip of the partition wall.However, if the area of the tip part is small, thermal stress is concentrated on this tip part, and cracks occur in this joint part. Can occur. Conversely, in the case of a shape where a flat part is formed at the tip of this joint,
Since a vortex is generated downstream of the flat portion and the flame is held to increase the temperature at the tip of the partition wall, it is necessary to increase the amount of cooling air ejected from the partition wall. Therefore, it is preferable to round the corner or provide a small end face from the viewpoint of alleviating the generated thermal stress. The optimum value of the roundness or the size of the end face at this time depends on the temperature generated at the joint and the material used.
A range of 6 mm seems to be good.

The joining position of the partitions 6A and 6B is
They are joined so as to be longer than the radial length L ₂ of the A.
The partition walls 6A and 6B are provided with a plurality of rows of ring-shaped lips 16 on the wall surface.

The purpose of this lip 16 is to form film air 18 along the partition wall surface through an air hole 17 opened in the partition wall from the upstream of the partition wall. The film air 18 has the effect of suppressing the generation of vortices on the partition wall surface by flowing along the gas flow along the partition wall surface, and also has the cooling effect of the partition wall. In order to obtain such an effect, the partition is provided with an air hole 17 for supplying film air 18 and a lip 16 for changing the flow of the film air 18 along the partition 6. Lip 16 on bulkhead
Determines the number of lips installed on the wall so that the next lip is installed within a range where the film air 18 from the lip 16 does not lose the film effect due to diffusion.

If the number of lips is too large, more air is required for the film air, so that less air is supplied to the premixing side, and the effect of reducing NOx is reduced. In this embodiment, the lips are arranged in two rows on the wall surface of the diffusion-side partition 6A and in one row on the wall surface of the premixing-side partition 6B.
The air from the upstream is blown out from the plurality of holes of the lip portion, the flow is changed by the lip structure, and is blown downstream along the partition. The film air 18 from the partition wall is used for the diffusion side partition wall 6.
A is ejected in the same direction as the streamline of the gas flow from the diffusion combustion burner 2, and is ejected from the premixing partition wall 6 </ b> B in the same direction as the streamline of the gas stream from the premixed combustion burner 10.

FIG. 5 shows another embodiment of the lip structure. In this embodiment, the partition 6 is composed of a plurality of plates to integrate the lip 16 and the partition,
The partition structure is simplified. In addition, the structure of this structure eliminates the protrusion of the lip 16 to enhance the effect of the film.

Next, the operation will be described. In a combustion state in which a flame is formed in both the diffusion combustion burner 2 and the premix combustion burner 10, the diffusion flame 9 has a partition wall 6A.
The flame is held in the downstream circulation region, and the premixed flame 15 is held by the circulation flow 14 formed downstream of the flame holding ring 13 at the outlet of the premixed combustion burner. In this respect, in the conventional device, FIG.
As shown in FIG. 0, the unburned diffusion fuel 20 and the unburned premixed gas 21 together form a shear layer flame 22 in a shear layer formed downstream of the end of the partition wall 6. I have.

The shear layer flame 22 is very unstable and is formed at a position close to the premixed flame 15A formed on the outer periphery thereof. turn into. In this regard,
In the present invention, as shown in FIG. 4, by providing the partition wall 6A extending from the diffusion burner side and the partition wall 6B expanding from the premix combustion burner side, the shear layer flame 22A formed by the diffusion fuel 20 is premixed. Since the shear layer flame 22B formed by the gas 21 can be formed separately and the shear layer flame 22A can be formed at a distance from the premixed flame 15A, the premixed flame 15A and the shear layer flame 22A interfere and burn. It is possible to suppress the occurrence of instability and leading to combustion oscillation.

In the conventional structure, the partition wall cooling air flows through the inside of the partition wall. In this case, since only the diffusion combustion air and the diffusion fuel flow on the partition wall surface,
A stagnation region is easily generated on the partition wall surface, and the stagnation region makes the shear layer flame 22A unstable. In the present invention, the structure in which the film air 18 flows along the gas flow from both the partition walls allows the formation of the shear layer flame 22.
In addition to fixing the flame holding point of A downstream of the partition wall tip, it is possible to reduce the combustion vibration by setting the shear layer flame 22A to a flame having a small influence so as not to give a clear flame holding point to the shear layer flame 22A. it can. Since the shear layer flame 22B uses only unburned premixed gas as fuel, it becomes a very weak flame as compared with the shear layer flame 22A, and the influence on the premixed flame 15A is negligible.

The junction between the partition walls 6A and 6B tends to be high in temperature due to the formation of a flame on the downstream side, but can be prevented from becoming high temperature due to the cooling effect of the film air 18 from the partition walls.

When aiming at lowering NOx by lean premixing, the lean premixed flame tends to be unstable. However, by controlling the shear flame that causes combustion oscillation by the above-described method, the premixing ratio can be reduced. Can be expected to reduce NOx, and the occurrence of combustion due to unstable combustion can be reduced.

Next, a combustor according to another embodiment of the present invention will be described with reference to FIGS. The combustor of this embodiment is different from the first embodiment in that a plurality of premixed combustion burners 10 are annularly arranged around a diffusion combustion burner 2 installed at the center of the combustor. Although the present embodiment has a structure of six premixed combustion burners, the number of premixed combustion burners may be any number. A conical partition wall 6A is provided at the outlet of the diffusion combustion burner, and a partition wall 6B whose cross-sectional area increases from the premixed combustion burner side to the diffusion combustion burner side is arranged so as to surround the partition wall 6A. The partition wall 6B has a structure in which a plurality of premixed combustion burners 10 and a part thereof are joined. Partition wall 6
Both A and 6B have a lip structure 16 so that air can be supplied along the gas flow.

In the present embodiment, the premixed flame 15 is held by the circulating flow 102 of the swirling of the premixed gas given by the swirler 101 upstream of the premixer. Even in the case of such a flame holding form, it is important to control the shear layer flame formed between the diffusion flame and the premixed flame as in the first embodiment.

As in the present embodiment, the diffusion-side partition 6A and the premixing-side wall 6B are installed at the outlet of the diffusion combustion burner, and cooling air is supplied to the partition along the gas flow, so that a plurality of swirling burners can be formed. Even in such a case, it is possible to control the shear layer flame formed at the tip of the partition wall, so that stable combustion can be performed.

A combustor according to a third embodiment of the present invention will be described with reference to FIGS. In the combustor of this embodiment, the premix burner 10 is shorter than that of the second embodiment, and an annular premix chamber 201 centering on the diffusion combustion burner 2 is arranged downstream of the premix burner 10. Although the present embodiment has a structure of six premix burners, the number of the premix burners may be any number. The diffusion combustion burner at the center of the combustor is provided with a partition wall 6A whose cross-sectional area is increased downstream at the outlet thereof, and a lip 16 is provided on the partition wall surface.

An annular premixing chamber 201 is provided downstream of the premixed combustion burner so as to surround the diffusion combustion burner. The premixed chamber 201 is made sufficiently wide to make the premixed gas 21 uniform. I have. After the premixed gas 21 is sufficiently homogenized, the combustion in the combustion chamber 1 allows lower NOx.

The premixing chamber 201 has a structure provided with a partition wall which expands the cross-sectional area after the cross-sectional area toward the outlet is narrowed. It is designed to prevent flashback of the premixed flame by raising it. The upstream side of the throttle 203 of the premixing chamber is joined to the diffusion combustion burner, and the inside thereof is provided with a plurality of holes 202 for film air branching in the diffusion combustion burner so that the film air is branched from the diffusion combustion air. Structure.

The diffusion-side partition 6A is located downstream of the throttle of the premixing chamber.
An annular premixing-side partition wall is provided so as to surround the partition wall, and the partition wall surface has a lip structure. The front end of the premixing-side partition is joined to the diffusion-side partition. The air branched from the diffusion combustion air passes through the inside of the throttle of the premixing section and is ejected along the gas flow as film air 18 from a lip structure attached to the diffusion side and the premixing side partition 6B.

Next, the operation of this embodiment will be described. In the present embodiment, the premixed gas 12 is swirled by the swirler 101 on the upstream side, and then the flow velocity is increased by the throttle 203 of the premix chamber. The flame is held by 102. Although the shear layer flames 22A and 22B are generated downstream of the premixing chamber and downstream of the junction between the diffusion-side partition and the premixing-side partition, partition walls are provided at the diffusion combustion burner outlet and the premixer outlet. By providing the lip structure, the effect of controlling the shear layer flame 22 can be obtained as in the first and second embodiments.

As described above, in the combustor for a turbine formed as described above, the shear layer flame formed between the diffusion flame at the center of the combustor and the premixed flame formed at the outer periphery thereof. Is separated into a shear layer flame formed by the unburned diffusion fuel and a shear layer flame from the unburned premixed air, and the shear layer flame caused by the diffusion fuel is moved away from the premixed flame and the air flows along the partition wall surface. Accordingly, the effect of suppressing the formation of the shear layer flame prevents the premixed flame from becoming unstable due to the shear layer flame, thereby suppressing the occurrence of combustion oscillation.

Further, since the flame stability can be improved by this, even if the premixing ratio is increased for further lowering NOx, it is possible to suppress the occurrence of combustion oscillation.

[0050]

As described above, according to the present invention, even when aiming for a lower NOx emission concentration, the formation of a shear layer flame is reduced and the interference between adjacent flames is sufficiently reduced. Thus, it is possible to obtain a gas turbine combustor of this type which can form a stable flame with less combustion oscillation.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view showing one embodiment of a gas turbine combustor of the present invention.

FIG. 2 is a front view taken along line AA of FIG.

FIG. 3 is a schematic system diagram showing an air system of a gas turbine combustor of the present invention.

FIG. 4 is a vertical sectional side view showing a main part of a burner of the combustor for a gas turbine of the present invention.

FIG. 5 is a side view of a partition wall showing another embodiment of the gas turbine combustor of the present invention.

FIG. 6 is a longitudinal sectional side view showing another embodiment of the gas turbine combustor of the present invention.

FIG. 7 is a front view of FIG. 6;

FIG. 8 is a vertical sectional side view showing another embodiment of the gas turbine combustor of the present invention.

FIG. 9 is a front view of FIG. 8;

FIG. 10 is a longitudinal sectional side view showing a main part of a burner of a conventional gas turbine combustor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Combustion chamber, 2 ... Diffusion combustion burner, 3 ... Diffusion combustion fuel nozzle, 5 ... Swirl vane, 6A, 6B ... Partition, 7 ... Diffusion fuel dispersion air, 10 ... Premix burner, 11 ... Premix combustion Fuel nozzle, 12: premixing section, 13: flame holding ring, 1
4 ... circulating flow, 15 ... premixed flame, 16 ... lip, 17 ...
Air holes, 18: film air, 21: premixed air, 22
A, 22B: Shear layer flame, 23: Air, 24: Air compressor, 26: Combustor, 101: Swirler, 102: Circulation area, 201: Premixing chamber, 202: Hole for air branch, 20
3 ... Restriction of premixing chamber.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor, Isao Takehara 3-1-1, Sachimachi, Hitachi-shi, Ibaraki Pref. Hitachi, Ltd. Hitachi Plant (72) Inventor Yasutaka Komatsu 3-1-1, Sachimachi, Hitachi-shi, Ibaraki # 1 Inside Hitachi, Ltd.Hitachi Plant (72) Inventor Tetsuo Sasada 3-1-1 Sakaimachi, Hitachi, Ibaraki Prefecture Inside Hitachi, Ltd.Hitachi Plant (72) Inventor Nariki Kobayashi Hitachi, Ibaraki 7-2-1 Omikacho Hitachi Electric Power and Electricity Development Headquarters Co., Ltd. (72) Inventor Kazuyuki Ito 7-2-1 Omikacho Hitachi-city, Ibaraki Pref. Hitachi Electric Power and Electricity Development Headquarters

Claims (5)

[Claims] 1. A gas turbine combustor in which a diffusion combustion burner is provided at a central portion of a combustor, and an annular premix combustion burner is provided on an outer periphery of the diffusion combustion burner. In addition to providing a conical cylindrical inner partition wall whose burner outlet cross-sectional area increases downstream, a conical cylindrical outer partition wall whose burner outlet cross-sectional area increases downstream is provided at the outlet of the premixed combustion burner. ,
A gas turbine combustor characterized in that it is formed so as to join downstream end portions of the inner and outer partition walls. 2. A gas turbine combustor in which a diffusion combustion burner is installed at a central portion of a combustor, and an annular premix combustion burner is installed on an outer periphery of the diffusion combustion burner. A conical cylindrical inner partition wall whose burner outlet cross-sectional area increases toward the downstream side, and a conical cylindrical outer partition wall whose diameter decreases toward the downstream side on the outlet inner peripheral side of the premixed combustion burner. With
A combustor for a gas turbine, wherein a downstream end portion of each of the partition walls is joined, and a cooling air ejection hole for cooling the partition wall is provided in one or both of the inner and outer partition walls. 3. A diffusion combustion burner installed at the center of the combustor, and a premix combustion burner installed around the periphery of the diffusion burner, wherein the premix combustion burner surrounds the diffusion combustion burner. In a gas turbine combustor formed by juxtaposition of a plurality of cylindrical burners, the outlet of the diffusion combustion burner is provided with a conical cylindrical inner partition wall whose burner outlet cross-sectional area increases toward the downstream, At the outlet of the premixed combustion burner, on the side of the diffusion combustion burner, a conical cylindrical outer partition wall whose diameter decreases toward the downstream is provided, and the downstream end portions of both the partition walls are joined, and the inner and outer partition walls are joined together. A gas turbine combustor characterized in that one or both of them are provided with a cooling air ejection hole for cooling each partition. 4. The gas turbine combustor according to claim 2, wherein the cooling air ejection hole is formed in a lip structure in which cooling air is ejected downstream along the partition wall surface. 5. The gas turbine combustor according to claim 1, further comprising a swirl vane for generating a swirling premixed airflow downstream of the premixed combustion burner.