JPH0942672A - Gas turbine combustor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas turbine combustor wherein mixing is promoted within a short mixing distance, and even with a low load, i.e., even with the reduced amount of heat production stable fire transfer from a pilot burner to a main burner is ensured, and an operation range of a gas turbine is expanded. SOLUTION: A gas turbine combustor is constructed with a pilot burner 1 and a premixing main burner 10 disposed to surround the former. In the combustor the main burner 10 is constructed with a fuel nozzle 12, an annular premixer 14 for mixing a fuel jetted from the fuel nozzle and air, and a baffle disposed downstream the premixer. There is further provided a plurality of concave parts 4 in an internal peripheral side cylinder surface of the annular premixer, each concave part being directed toward an outer peripheral side and having its height and width in the flow direction of mixed gas being increased. High temperature gas burned in the pilot burner flows to the inside of the concave part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a gas turbine combustor, and more particularly to a gas turbine combustor having a pilot burner for diffusion combustion and a main burner for premix combustion.

[0002]

2. Description of the Related Art Conventionally known methods for promoting mixing of this type of combustor include, for example, Global Gas Turbine News.
Lobed Mixer, as disclosed in August 1993
The basic structure is known. However, regarding the application of the low-load burner switching technology (pilot burner / main burner) of the premixed combustor used in the gas turbine combustor, the high-temperature combustion gas and the low-temperature unburned premixed gas are mixed. Therefore, it is very difficult to ensure the reliability of the structure in terms of temperature, and it has not necessarily been put to practical use.

This Lobed Mixer structure is used for the mixed flame stabilizer structure of a ramjet engine. This is a mixture of low temperature hydrogen fuel and air, and it is a high temperature like a gas turbine combustor. No consideration is given to mixing with gas, and it is not sufficient in terms of reliability.

[0004]

In a gas turbine combustor started by a pilot burner which mainly adopts diffusion combustion, it is necessary to ignite the main bar bar as the load increases. In recent environment-adaptive gas turbine power generation systems, improvement of cycle efficiency by combining with a steam turbine and reduction of NOx emissions by premixed combustion have been achieved. By adopting this combined cycle and premixed combustion, The following two problems appear in the combustor.

That is, one has a low partial load, for example 3
The gas turbine will be operated over a wide range from 0% load to 100% rated load, and it will be necessary to switch to the main burner at low load, that is, to ignite the main burner in the low load zone. It is difficult to ignite. Second, low NOx operation is required for the entire operating range, and therefore low NOx is achieved even at partial load.
Premixed combustion is adopted so that combustion is performed, and at partial load, the fuel-air ratio is very thin, that is, the fuel-air ratio state is close to the combustible limit, and stable combustion is difficult.

The load switching from the pilot burner (diffusive combustion) to the main burner (premixed combustion) has a very poor ignition condition, and conventionally, as one of the measures, an air flow rate control for partially bypassing the combustion air, or By staging the burner, the fuel-air ratio of the burner is locally increased to create conditions that make it easier to ignite.

However, the air flow rate control tends to have a complicated structure, requires a highly accurate air flow rate control structure, and has a problem in that the staging of the burner narrows the operable range. . In order to solve these problems, load switching technology that can reliably ignite a low air-fuel ratio premixed mixture within a short time is required, and it is possible to ignite the premixed mixture in a short time, that is, a short distance. Mixing promotion technology that raises the temperature to a certain degree is essential.

The present invention has been made in view of the above, and an object of the present invention is to promote the mixing within a short mixing distance so that even if the load is low, that is, the calorific value is small, a pilot burner is used. It is an object of the present invention to provide a gas turbine combustor of this type that can perform stable fire transfer to the main burner and can expand the operation range of the gas turbine.

[0009]

That is, the present invention relates to a gas turbine combustor comprising a pilot burner and a premixing main burner arranged so as to surround the pilot burner, wherein the main burner is provided with a fuel nozzle. It is composed of an annular premixer for mixing the fuel and air ejected from the fuel nozzle, and a flame stabilizer arranged on the downstream side of this premixer, and the inner peripheral cylindrical surface of the annular premixer. In addition, a plurality of recesses that increase in height and width in the flow direction of the air-fuel mixture are provided toward the outer peripheral side, and the hot gas burned by the pilot burner is formed inside the recesses to achieve the intended purpose. It is something that is done.

[0010]

That is, in the gas turbine combustor thus formed, the premixture and the high temperature combustion gas are concave due to the concave portion provided in the premixer and the auxiliary combustion chamber convex portion of the pilot burner, Vertical vortices are generated by the flow velocities on both sides of the convex portion, the flow velocity difference between the two at the rear end, and the vortices generated from the concave portion and the leading edge of the convex portion. Is promoted, even if the load is low,
That is, even in a state where the heat generation amount is small, stable fire transfer from the pilot burner to the main burner is possible.

Further, by changing the heights and widths of the concave and convex portions, the characteristics of the vortices generated in the subsequent flow are different, and even when oscillating combustion occurs, the frequency is different between the concave and convex portions. Since they are different, it is possible to sufficiently suppress the development of combustion vibration due to resonance of the entire combustor.

Further, since the flame propagation tubes are provided on the outlet liners of the concave and convex portions, the high temperature gas upon ignition by the pilot burner increases its pressure and supplies a large amount of energy to the adjacent combustor. It is possible to make the flame propagation more reliable.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. 1 and 2, a main part of the gas turbine combustor is shown in cross section. The combustor is mainly arranged in a central portion of the pilot burner 1 and annularly arranged so as to surround the pilot burner.
4 is composed of a premixed combustion main burner 10 having a No. 4, a sub-combustion chamber 3 of the pilot burner located downstream of the pilot burner, and a main combustion chamber 18 surrounded by a liner 16.

Further, in particular, the inner peripheral cylindrical surface of the annular premixer 14 is provided with a plurality of premixer recesses 4 which increase in height and width in the flow direction of the premixed gas 11 toward the outer peripheral side. The hot gas burned by the pilot burner 1 is formed so as to flow inside the recess.

When operating with this configuration, 30
The partial load up to about% is operated only by the pilot burner 1. That is, the pilot burner 1 burns with the fuel ejected from the fuel nozzle 12 and the combustion air 15 swirled by the swirl vanes 2, and the combustion gas 20 that has risen to a predetermined temperature is supplied to the turbine to generate power. Will occur. At a load of about 30%, by mixing the high temperature combustion gas 20 combusted by the pilot burner with the premixed gas 11 of the main burner 10 to raise the premixed gas temperature to the ignition temperature or higher, the main burner premixed gas mixture 14 Can be burned.

The premixed fuel-air / air ratio of the main burner at partial load is below the flammability limit, and the high temperature combustion gas of the pilot burner must be mixed into the premixed gas as much as possible and the temperature must be above the temperature at which the combustion reaction proceeds. Must
It is necessary to promote mixing of the pilot burner combustion gas 20 and the premixed gas 14 over a short distance.

In the present invention, as described above, by providing the premixing concave portion 4 which is recessed toward the outer peripheral side on the inner peripheral side cylindrical surface of the annular premixer 14, the combustion gas 20 and the premixed gas 14 are formed behind this concave portion. Mixing is promoted by the vertical vortex generated in the flow, and at the same time, the provision of the concave portion 14 increases the contact area of both gases, and the degree of mixing can be increased in a shorter distance to retain the high temperature combustion gas 20. Energy is transferred to the premixed air mixture 11, the combustion reaction is greatly increased due to the temperature rise, and operation with a main burner from a low load premixed air fuel mixture having a low fuel-air ratio becomes possible.

In the present embodiment, it seems that the high temperature combustion gas flows inside the premixer recess 4 and the wall temperature of the recess rises. However, since the premixture 14 flows outside the recess, this Since it is cooled by the air-fuel mixture 14, the rise in wall temperature of the recess is prevented, and there is no particular problem. Of course, when the cooling performance on the premixed air side is not sufficient, although not shown in the figure, the cooling performance may be improved by flowing cooling air to the outer peripheral side of the recess.

FIGS. 3 and 4 show another embodiment of the present invention. In this embodiment, the auxiliary combustion chamber convex portion 5 is provided in the flow path of the premixer 14 from the inner peripheral side thereof. Even if formed in this way, the same effect as that of the above-described embodiment can be obtained.

5 and 6 show another embodiment of the present invention, in which the main burner 10 is composed of a cylindrical multi-nozzle. In this embodiment, the outlet of the main burner 10 is provided on the upstream side of the outlet of the auxiliary combustion chamber convex portion 5, and the auxiliary combustion chamber convex portion is generated by the premixed gas 11 mixed in the premixer 14 of the main burner. The structure is cooled. However, since the cooling of the convex portion by the premixed air does not reach the entire surface, the cooling flow path 19 for the cooling air 13 is provided outside the convex portion.
Is provided.

FIGS. 7 and 8 show a structure in which the height and width of the premixer recess 4 in the embodiment shown in FIG. 1 are different from each other in the adjacent recesses. In the present embodiment, the same effects as those of the above-described embodiments can be obtained, and in addition, since the frequency characteristics of the vertical vortex generated after the recess 4 are different in the adjacent recesses, when the oscillating combustion occurs, However, all the main burners do not resonate at the same time, and the combustion vibration generated can be reduced.

FIGS. 9 and 10 show another embodiment of the present invention. By providing a flame propagation pipe 25 in the outlet liner 16 of the auxiliary combustion chamber convex portion 5, the flame spread pipe 25 is provided to the adjacent combustor when the combustor is ignited. The flame propagation performance can be exhibited without being hindered by the combustion air of the main burner around the pilot burner, and stable flame propagation can be achieved. In addition, a gap is provided between the sub-combustion chamber 3 and the premixer 14 for assembling, so that it is possible to prevent the air from flowing to the combustion chamber from other than the combustion burner with a low N.
It is wasteful in that the premixed gas is made as lean as possible for Ox conversion. Therefore, a cylindrical portion is provided on the upstream side of the auxiliary combustion chamber convex portion 5, and a spring-like seal structure is attached thereto, so that the amount of leaked air can be reduced and low N
It becomes possible to use more premixed combustion air necessary for achieving Ox conversion.

11 and 12 show another embodiment of the present invention. The entire combustor includes a pilot burner 1, a premixing main burner 10, an auxiliary combustion chamber 3, and a liner 16. The pilot burner 1 operates from the start up to a partial load of 30%, and the fuel from the F2 fuel nozzle 12 is premixed for higher loads,
Stable combustion is performed by the flame stabilizer 9 provided at the outlet of the premixing 14a.

After that, air and fuel are uniformly mixed by the vortex generators 35 and 36 for promoting mixing provided in the premixer, and low NOx combustion can be achieved. Also,
When switching the load from the pilot burner 1 to the main burner 10, the fire transfer vortex generators 37, 38 are provided to the premixer and the outlet of the sub chamber so that the energy from the pilot burner can be quickly transmitted to the main burner.
The high-temperature combustion gas from the sub chamber and the unburned pre-mixture from the premixer are well mixed, and the fire is transferred to the main burner even under low partial load conditions without causing large load fluctuations. be able to.

Further, the flame stabilizer at the outlet of the premixer is provided with vortex generators 30, 31 which are notches for improving flame holding performance and stability against combustion vibration at the inner and outer peripheral ends thereof. , Dynamic combustion stability is improved.

FIGS. 13 and 14 show FIGS. 11 and 12.
However, the pilot burner 1 is a revolving flame holding burner. Also in this embodiment, FIG.
The same effect as can be achieved.

In FIG. 15, instead of the flame stabilizer 9 in FIG. 11, the outflow direction of the premixer outlet is inclined to the hot gas flow from the pilot burner (9a, 9b) to mix the unburned premixed gas with the hot gas. With this structure, the same effects as in FIG. 11 can be obtained according to the present embodiment as well, and since the flame stabilizer does not intensively promote combustion, it is possible to operate with small combustion oscillation.

Another embodiment will be described with reference to FIGS. 16 and 17. A combustor outer cylinder 51 is closed by a fuel supply flange 52. 12 is a fuel nozzle,
Reference numeral 1 is a pilot burner around which eight main burners 10 are annularly arranged. These are fixed to the connecting member 57, a combustion region is formed inside the liner 16 on the downstream side thereof, and the combustion gas is guided to the turbine by the transition piece 59.

The pilot burner 1 has a cylindrical shape, in which a swirl vane 60 and a swirler 61 having a smaller diameter are arranged, and a double cylindrical fuel nozzle 12 is provided in the center portion thereof to upstream side. And fuel are supplied separately to the two downstream locations. The main burner 10 has a cylindrical shape, and a triangular plate-shaped vortex generator 62 attached to the upstream inner peripheral wall at an angle of attack with respect to the inflowing air is provided in an annular shape with the apex angle toward the burner central axis. A rod-shaped fuel nozzle 12 is placed at the center of the burner.

Next, the operation of the gas turbine combustor configured as described above will be described. At the start of combustion, the fuel is supplied only to the downstream injection port of the fuel nozzle 12 of the main burner 10 to cause diffusion combustion. When the load increases, fuel is also supplied to the upstream injection port of the fuel nozzle 12 to perform premixed combustion. At this time, since the outer peripheral end of the swirl vane 60 is not connected to other members and is open as shown in FIGS. 18 and 19, it also functions as a vortex generator. The vertical vortex discharged from the swirl vanes 60 promotes the mixing of air and fuel, and forms a uniform premixed gas.

When the load is further heavy, fuel is also supplied to the fuel nozzle of the main burner 10 to start combustion. At this time, the vertical vortexes emitted from the swirl vanes 60 cause the combustion gas of the pilot burner 1 to move from the main burner 1
Heat is actively supplied to 0, and good fire transfer property can be expected.

As shown in FIG. 20, the swirl vane 60 can be provided with a lip to divide the outer peripheral end into a triangular shape so as to generate a stable vortex. Further, as shown in FIGS. 21 to 23, the outer peripheral end of the swirling blade 60 may be fixed and the blade may have a cut. In this case, a similar effect can be expected due to the vertical vortex generated from the cut portion.

Inside the main burner 10, a vertical vortex is generated from the vortex generator, and at the same time, the air flow swirls around the burner axis. Therefore, the high cost of both promotes the mixing of air and fuel. Even if the holding angle of the vortex generator against the air flow is small, a uniform mixture can be formed and the pressure loss can be reduced.

As described above in various ways, in the combustor of the present invention, a plurality of recesses are provided on the inner peripheral cylindrical surface of the annular premixer arranged around the pilot burner, and inside the recesses. By allowing the combustion gas of the pilot burner to flow, it is possible to transfer the pilot burner from the main burner to the main burner at a partial load without fail, even when the premixture of the main burner has a low fuel-air ratio and a low partial load. It is possible to operate a low NOx combustor in a wide load band without using a control mechanism such as flow rate control.

Similar to the concave portion of the premixer, the same effect as above can be obtained by the convex portion provided at the outlet of the auxiliary combustion chamber of the pilot burner in the flow of the premixed main burner.

By making the heights and widths of the plurality of concaves and convexes in one combustor in various types, when oscillating combustion occurs, the flow of the concave and convex wakes can be reduced. Since the frequency characteristics are distributed, all concave and convex combustions do not resonate, so that large combustion vibrations can be prevented from occurring and the reliability of the device is improved.

By providing a heat transfer promoting structure or a cooling flow path on the premixed gas flow side of the concave and convex portions, it is possible to reduce the temperature rise on the wall surface of the concave and convex portions and raise the combustion gas temperature of the pilot burner to a high temperature. As a result, it is possible to transfer the fire to the main burner with a lower premixed fuel-air ratio, and to widen the operation range.

By providing a flame propagation pipe in the concave and convex outlet liners, the energy required for flame propagation to another adjacent combustor at the time of ignition of the combustor is used for combustion in the surrounding main burner. Propagation is possible without being obstructed by air, and stable and reliable flame propagation is possible.

By providing a cylindrical portion upstream of the convex portion of the auxiliary combustion chamber with respect to the seal structure for reducing the leakage air flow rate flowing through the gap generated between the auxiliary combustion chamber and the premixer of the main burner, Since the spring-like seal structure operates effectively, the leakage air flow rate can be reduced. Therefore, by increasing the flow rate of air that can be used for premixed combustion, combustion can be performed with a premixed gas having a lower fuel-air ratio, and the NOx emission amount can be reduced.

[0040]

As described above, according to the present invention, the mixing of air and fuel is promoted within a short mixing distance, and even if the load is low, that is, the amount of heat generation is small,
It is possible to obtain a gas turbine combustor of this type that can perform stable fire transfer from the pilot burner to the main burner and can expand the operation range of the gas turbine.

[Brief description of drawings]

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

FIG. 2 is a view on arrow A in FIG.

FIG. 3 is a vertical sectional side view showing another embodiment of the gas turbine combustor of the present invention.

FIG. 4 is a view taken in the direction of arrow B in FIG. 3;

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

FIG. 6 is a view taken in the direction of the arrow C in FIG. 5;

FIG. 7 is a vertical sectional side view showing another embodiment of the gas turbine combustor of the present invention.

FIG. 8 is a view on arrow D of FIG.

FIG. 9 is a vertical sectional side view showing another embodiment of the gas turbine combustor of the present invention.

FIG. 10 is a view taken in the direction of arrow E in FIG. 9;

FIG. 11 is a vertical sectional side view showing another embodiment of the gas turbine combustor of the present invention.

FIG. 12 is a view on arrow F of FIG.

FIG. 13 is a vertical sectional side view showing another embodiment of the gas turbine combustor of the present invention.

FIG. 14 is a view on arrow G in FIG.

FIG. 15 is a vertical sectional side view showing another embodiment of the gas turbine combustor of the present invention.

FIG. 16 is a vertical sectional side view showing another embodiment of the gas turbine combustor of the present invention.

17 is a view on arrow H of FIG.

FIG. 18 is a vertical sectional side view showing another embodiment of the gas turbine combustor of the present invention.

FIG. 19 is a view on arrow I of FIG.

FIG. 20 is a perspective view showing the shape of blades used in the gas turbine combustor of FIG. 18.

FIG. 21 is a vertical sectional side view showing another embodiment of the gas turbine combustor of the present invention.

FIG. 22 is a view on arrow J of FIG. 21.

FIG. 23 is a perspective view showing the shape of blades used in the gas turbine combustor of FIG. 21.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Pilot burner, 3 ... Secondary combustion chamber, 4 ... Premixer concave part, 5 ... Premixer convex part, 10 ... Main burner, 14 ... Premixer, 16 ... Liner, 18 ... Main combustion chamber, 25 ... Flame Propagation tube, 60 ... Swirl vane.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Noriyuki Hayashi, Noriyuki Hayashi, 502 Jinritsucho, Tsuchiura-shi, Ibaraki Hiritsu Seisakusho Co., Ltd.Mechanical Research Institute (72) Toshifumi Sasao, 502 Kintate-cho, Tsuchiura-shi, Ibaraki Hiritsu Seisakusho Co., Ltd. Mechanical Research Laboratory (72) Inventor Hiromi Koizumi 502 Jinritsu-cho, Tsuchiura-shi, Ibaraki Hiritsu Seisakusho Co., Ltd. (72) Inventor Osamu Yokota 502 Jinmachi-cho, Tsuchiura-shi, Ibaraki Hiritsu Seisakusho Co., Ltd. 72) Inventor Kazuyuki Ito 7-1, 1-1 Omika-cho, Hitachi-shi, Ibaraki Hitachi Co., Ltd. Hitachi Research Laboratory (72) Inventor Masaya Otsuka 7-2-1 Omika-cho, Hitachi-shi, Ibaraki Hitachi Electric Power & Electric Machinery Development Division

Claims (18)

[Claims] 1. A pilot burner and a premixing main burner arranged so as to surround the pilot burner, the premixing main burner having an annular shape for mixing a fuel nozzle and fuel and air ejected from the fuel nozzle. In a gas turbine combustor having a premixer, the inner peripheral side wall surface of the annular premixer has a plurality of recesses toward the outer peripheral side whose height and width in the flow direction of the premixed gas increase. The gas turbine combustor is characterized in that a high temperature gas burned by the pilot burner flows inside the recess. 2. A pilot burner, a sub-combustion chamber located downstream of the pilot burner, in which combustion of the pilot burner is performed, and a premixing main burner arranged so as to surround the periphery of the sub-combustion chamber. A main combustion chamber located downstream of the premixing main burner, in which combustion of the premixing main burner is performed, and a premixer of the premixing main burner is formed in an annular shape around the auxiliary combustion chamber. In the gas turbine combustor, the premixer outlet inner peripheral wall surface of the premixer is provided with a plurality of recesses toward the outer peripheral side whose height and width in the flow direction of the premixed gas increase, and A gas turbine combustor characterized in that a high temperature gas burned by the pilot burner is circulated inside. 3. The gas turbine combustor according to claim 1, wherein the plurality of recesses are formed so as to have different heights or widths, and the different recesses are arranged in parallel. 4. A fin or a turbulence promoter for promoting heat transfer performance is provided in a flow passage located on the opposite side of the combustion gas flow passage from the recess.
A gas turbine combustor as described. 5. The gas turbine combustor according to claim 1, wherein a vortex generator for mixing promotion is provided on a surface of the recess in the premixer where the premixed gas flows and on an upstream side thereof. 6. A pilot burner, a sub-combustion chamber located downstream of the pilot burner, in which combustion of the pilot burner is performed, and a premixing main burner arranged so as to surround the periphery of the sub-combustion chamber. A main combustion chamber located downstream of the premixing main burner, in which combustion of the premixing main burner is performed, and a premixer of the premixing main burner is formed in an annular shape around the auxiliary combustion chamber. In the gas turbine combustor, a plurality of convex passages are provided in the auxiliary combustion chamber portion near the main burner outlet portion of the pilot burner so as to enter the premixer passage of the main burner. A gas turbine combustor characterized in that a gas burned by a pilot burner is circulated in the partial flow path. 7. A pilot burner, a sub-combustion chamber located downstream of the pilot burner, in which combustion of the pilot burner is performed, and a premixing main burner arranged so as to surround the periphery of the sub-combustion chamber. A main combustion chamber located downstream of the premixing main burner, in which combustion of the premixing main burner is performed, and a premixer of the premixing main burner is formed in an annular shape around the auxiliary combustion chamber. In the gas turbine combustor, the auxiliary combustion chamber portion of the pilot burner near the outlet of the premixing main burner is provided with a plurality of convex passages that spread in the gap formed between the cylindrical or rectangular main burners. The gas turbine combustor characterized in that 8. The gas turbine combustor according to claim 6, wherein the height and the width of the convex flow path are formed so as to gradually increase in the premixed gas flow direction of the pilot burner. 9. The main burner outlet and the pilot burner auxiliary combustion chamber are arranged so that the premixed air of the main burner flows along the auxiliary combustion chamber convex passage of the pilot burner. Gas turbine combustor. 10. The gas turbine combustor according to claim 6, wherein the convex portion of the auxiliary combustion chamber of the pilot burner has a plurality of heights or widths. 11. The gas turbine combustor according to claim 6, wherein the sub-combustion chamber convex portion of the pilot burner is formed so as to allow air to flow behind the surface of the pilot burner which is in contact with the combustion gas. 12. The gas turbine combustor according to claim 6, wherein the outlet liner at the circumferential position of the auxiliary combustion chamber of the pilot burner is provided with a flame propagation tube. 13. A cylindrical auxiliary combustion chamber portion is provided on the upstream side of the convex portion of the pilot burner auxiliary combustion chamber.
The gas turbine combustor according to 7 or 8. 14. A gas turbine combustor comprising a pilot burner and a premixing main burner arranged so as to surround the pilot burner, wherein a vortex generator for promoting mixing in the premixer and a flame stabilizer at its outlet. A gas turbine combustor characterized in that a plurality of vortex generators are provided on the pilot burner side inner periphery of the premixer outlet and the outer periphery of the pilot burner auxiliary combustion chamber outlet. 15. A gas turbine combustor composed of a pilot burner and a premixing main burner arranged so as to surround the pilot burner, wherein a vortex generator for promoting mixing in the premixer and a flow direction of an outlet thereof. Is inclined toward the combustion gas from the central pilot burner, and a plurality of vortex generators are provided at the pilot burner side inner circumference of the premix outlet and the pilot burner auxiliary combustion chamber outlet outer circumference. Turbine combustor. 16. A pilot burner having swirl vanes and a premixing main burner arranged so as to surround the pilot burner, wherein the premixing main burner feeds a fuel nozzle and fuel and air ejected from the fuel nozzle. A gas turbine combustor including an annular premixer for mixing, characterized in that a gap is formed between the blade outer peripheral portion of the burner having the swirl blade and an annular ring around the blade outer peripheral portion. And a gas turbine combustor. 17. The gas turbine combustor according to claim 15, wherein said swirl vane outer peripheral portion is formed in a triangular shape which becomes higher in the direction of gas flow. 18. A pilot burner having swirl vanes and a premixing main burner arranged so as to surround the pilot burner, wherein the premixing main burner feeds a fuel nozzle and fuel and air ejected from the fuel nozzle. A gas turbine combustor having an annular premixer for mixing, wherein a blade of the burner having the swirl blade is provided with a notch extending in the circumferential direction.