JP2005233574A - Combustor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a combustor capable of reducing the generation of NOx per charged fuel, preventing the generation of combustion vibration and the generation of flashback, having reduced environmental load and preventing the combustor and a structure connected with the combustor from being broken by the vibration. <P>SOLUTION: This combustor BS1 comprises a casing 1, a cylindrical premixing cylinder 2, a combustion cylinder 3 communicated with the premixing cylinder 1, an air inflow part 11 for supplying the air for combustion, an airflow introducing part 13 for introducing the airflow to the premixing cylinder 2 while changing the direction of airflow, a pilot nozzle 4 mounted on an axis of the premixing cylinder 2, and main premixing nozzles 5 extended approximately in parallel with the pilot nozzle 4, and mounted in the premixing cylinder 2 at equal center angle intervals. The main premixing nozzles 5 respectively have a downstream-side fuel injection pegs 53, a first upstream-side fuel injection peg 71a is mounted at an upstream side of the air inflow part, and a second upstream-side fuel injection peg 72a is mounted between the first upstream-side fuel injection peg 71a and the main premixing fuel injection peg 53. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a combustor that supplies combustion gas to a turbine of a gas turbine by mixing and burning combustion gas supplied from a compressor and fuel.

  In a conventional gas turbine combustor, a diffusion combustion method in which fuel and combustion air are ejected from different nozzles and burned is often used. However, in recent years, a premixed combustion method that is more advantageous for reducing thermal NOx has been used instead of the diffusion combustion method described above. In the premixed combustion method, fuel and combustion air are mixed in advance on the upstream side of a nozzle and ejected as an air-fuel mixture from the nozzle for combustion.

  FIG. 6 shows a cross-sectional view of an example of a premixed combustion type combustor. A combustor BS5 shown in FIG. 6 has a casing 91, a premixing cylinder 92, and a combustion cylinder 93, and a pilot nozzle 94 is disposed on the central axis of the premixing cylinder 92. A plurality of main premixing nozzles 95 extending substantially parallel to the pilot nozzle 94 are arranged at equal central angular intervals in the circumferential direction.

  The main premixing nozzle 95 is provided with a main fuel rod 951 for supplying fuel. A pilot swirl vane 941 is disposed around the pilot nozzle 94. A fuel injection hole 942 for ejecting fuel is formed at the tip of the pilot nozzle 94.

  A premix swirl vane 952 is disposed around the main fuel rod 951 of the main premix nozzle 95. The main premixing nozzle 95 is provided with a plurality of fuel injection pegs 953 extending radially outward from the side wall of the main fuel rod 951 at equal central angular intervals in the circumferential direction. The bar 951 is in communication. A plurality of fuel injection holes 954 are provided in the fuel injection peg 953, and fuel is injected from the fuel injection holes 954 to mix fuel and combustion air.

  The combustor BS5 is provided with an air inflow portion 911 through which combustion air flows. The combustion air that has flowed in from the air inflow portion 911 is injected with fuel from an upstream fuel injection peg 97 provided in the casing 91. A lean mixture is formed. The lean air-fuel mixture is reversed by about 180 degrees at the end of the premixing cylinder 92 and flows into the premixing cylinder 92.

  The air-fuel mixture flowing into the premixing cylinder 92 flows into the main premixing nozzle 95 and the pilot nozzle 94. The inflowing air-fuel mixture passes through the pilot swirl vane 941 and the premixed swirl vane 952, and turns into an airflow (swirl) swirling in the circumferential direction. The air-fuel mixture raises the temperature of the diffusion flame by fuel injection from the pilot fuel injection port 942 and stabilizes the flame.

  In addition, the air flowing into the main premixing nozzle 95 is mixed with the fuel injected from the fuel injection peg 953, and further passes through the swirl vane 952 in a state of a rich mixture to form a swirl. Mix so that there is no shading. The air-fuel mixture flowing into the gap 96 between the premixing cylinder 92 and the main premixing nozzle 95 is a combustion cylinder 93 as a cooling film Fi through a film hole 961 communicating with the combustion cylinder 93 through the gap 96 between the premixing cylinder 92 and the main premixing nozzle 95. Flow into. The air-fuel mixture ejected from the pilot nozzle 94 forms a pilot diffusion flame, and the air-fuel mixture ejected from the main premixing nozzle 95 contacts the pilot diffusion flame to form a main flame Bn and burns.

  In this way, fuel is injected into the combustion air in advance by the air inflow portion 911 to form a low-concentration air-fuel mixture, and then injected into the combustion cylinder 93 as a high-concentration air-fuel mixture by the main premixing nozzle 95. By doing so, it is possible to mix the fuel of the air-fuel mixture and the combustion air more uniformly.

  The fuel concentration (fuel / air ratio) of the air / fuel mixture is determined so that the combustion gas generated by the combustion of the air / fuel mixture reaches a predetermined temperature, but the fuel / air ratio partially increases in the air / fuel mixture ( If there is a portion that is not uniformly mixed, more NOx is generated in that portion. By using a premixed combustion type combustor, the uniformity of the air-fuel mixture can be further increased. As a result, it is possible to prevent the generation of the high temperature portion of the combustion gas due to the deviation of the fuel-air ratio, and it is possible to prevent the generation of NOx.

  By providing the upstream fuel injection peg 97, fuel can be mixed with pilot air and cooling film that are not used in the main premixing nozzle 95, and the concentration distribution at the outlet of the main premixing nozzle 95 tends to be uniform. The fuel concentration is made uniform throughout the combustor. The more fuel injected from the upstream fuel injection peg 97, the greater the uniformity of the air-fuel mixture. However, in order to prevent the cooling film from burning, but not limited thereto, here, the upstream fuel injection peg 97, the main fuel injection peg 97, About 10% to 30% of the fuel injected from the fuel injection peg 953 and the pilot nozzle 94 is injected.

Furthermore, the pilot air or the film air becomes an air-fuel mixture, so that the flame holding property can be improved when the fuel stabilization (flame holding property) by the diffusion flame from the pilot nozzle 94 is insufficient.
Japanese Patent Laid-Open No. 10-318541 JP 2003-65536 A JP 2003-120934 A

  However, as the fuel injection amount injected from the upstream fuel injection peg 97 increases, the air-fuel mixture is mixed more uniformly. However, when the ratio of fuel injected from the upstream fuel injection peg 97 is increased, Combustion vibration occurs. When combustion vibration occurs, a loud vibration noise is generated, and the structure may be destroyed by resonance of the combustion vibration with the structure.

  It is known that the frequency oscillated by the combustion vibration varies depending on the position of the upstream fuel injection peg 97. When combustion vibration occurs, it is effective to move the upstream fuel injection peg 97. However, even if the upstream fuel injection peg 97 is moved, combustion vibration having a frequency different from the frequency of the combustion vibration may occur.

  In view of the above problems, the present invention aims to promote the mixing of a premixed mixture of fuel and combustion air, and forms a premixed mixture having a uniform fuel concentration, thereby generating NOx generated per fuel input to the combustor. An object of the present invention is to provide a combustor that can suppress combustion and prevent the occurrence of combustion vibrations.

  In order to achieve the above object, the present invention is a combustor for supplying combustion gas to a gas turbine, comprising a casing, a cylindrical premixing cylinder provided inside the casing, and combustion communicating with the premixing cylinder A cylinder, an airflow introduction section for introducing an airflow into the premixing cylinder by changing the direction of the airflow flowing through the air inflow section, a pilot nozzle provided on the central axis of the premixing cylinder, and the pilot nozzle A main premixing nozzle that extends substantially in parallel and is provided at equal central angular intervals in the premixing cylinder, the main premixing nozzle having a fuel rod for flowing fuel on a central axis, and the fuel rod The downstream fuel injection pegs are attached at equal central angular intervals and extend radially outward, and upstream fuel injection pegs arranged in a plurality of stages along the airflow direction on the upstream side of the premixing cylinder. Provided It is characterized in.

  According to this configuration, by dividing the upstream side fuel injection peg into a plurality of stages, the premixed gas flowing into the combustion cylinder is agitated with high uniformity and the occurrence of combustion vibration can be suppressed.

  As much as that, the amount of NOx generated per input fuel can be reduced and combustion vibrations can be prevented. The environmental impact is low, and the combustor and the structure connected to the combustor are vibrated and destroyed. Can be prevented.

  In the combustor configured as described above, an upstream side fuel disposed in the plurality of stages has a gap between the casing and the premixing cylinder, has an air inflow portion for supplying combustion air. At least one stage of the injection pegs may be provided in the air inflow portion and extend from the casing toward the premixing cylinder.

  In the combustor configured as described above, an air suction portion for allowing combustion air to flow into the casing is provided upstream of the air inflow portion, and at least of the upstream fuel injection pegs arranged in the plurality of stages. One stage may be provided in the air suction part.

  In the combustor configured as described above, at least one of the upstream fuel injection pegs arranged in the plurality of stages may extend radially inward from the casing and be provided at equal central angular intervals.

  In the combustor having the above-described configuration, at least one of the upstream fuel injection pegs arranged in the plurality of stages is provided at an equal center angle interval substantially parallel to the central axis of the premixing cylinder at the folded portion of the airflow. It may be a thing.

  In the combustor having the above configuration, the casing is provided with stays that are attached at equal central angular intervals and connected to the premixing cylinder, and the stay has a hollow portion in which fuel flows and a hollow surface on the inside. A fuel injection hole penetrating from the portion to the outside is formed, and the stay may be used as one stage of the upstream fuel injection pegs arranged in the plurality of stages.

  According to this configuration, by using the stay as one stage of the upstream side fuel injection pegs arranged in the plurality of stages, the number of constituent members is reduced, and the labor for manufacturing can be saved. Further, the pressure loss of the airflow can be reduced, and the air-fuel mixture can be mixed more uniformly.

  In the combustor having the above-described configuration, at least one of the upstream fuel injection pegs arranged in the plurality of stages may be attached to the fuel rods at equal central angular intervals and extend radially outward.

  Although the fuel flow path may be branched, according to this configuration, at least one of the downstream fuel injection pegs and the upstream fuel injection pegs arranged in the plurality of stages with the main fuel rod as the fuel supply path. Therefore, the fuel supply path can be simplified.

  Examples of the upstream fuel injection peg having the above-described configuration include a two-stage one having a first upstream fuel injection peg and a second upstream fuel injection peg.

  According to the present invention, the amount of NOx generated per input fuel can be reduced, combustion vibration can be prevented, and the combustor and the structure to which the combustor is connected vibrate with little environmental load. Thus, it is possible to provide a combustor that can be prevented from being broken.

  The best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 shows a cross-sectional view of the internal structure of a combustor according to the present invention.

  A combustor BS1 shown in FIG. 1 has a casing 1, a premixing cylinder 2, a combustion cylinder 3 connected to the premixing cylinder 2, and a pilot nozzle 4 disposed on the central axis of the combustion cylinder 3. Around the pilot nozzle 4, a plurality of main premixing nozzles 5 extending substantially parallel to the pilot nozzle 4 are arranged at equal central angular intervals in the circumferential direction. A gap 6 is formed between the main premixing nozzle 5 and the premixing cylinder 2, and an end of the gap 6 on the combustion cylinder 3 side is a cooling for forming a cooling film Fi on the inner surface of the combustion cylinder 3. A film hole 61 is formed.

  A pilot swirl vane 41 is disposed around the pilot nozzle 4. A fuel injection hole 42 for ejecting fuel is formed at the tip of the pilot nozzle 4. The tip of the pilot nozzle 4 forms a pilot diffusion flame, and an air-fuel mixture ejected from a main premixing nozzle 5 to be described later is sent to the combustion cylinder 3 to form a main flame Bn in contact with the pilot diffusion flame. And burn. The combustion gas after combustion is introduced into the turbine.

  The casing 1 is provided with an air suction portion 11 for supplying air compressed by a compressor. An air inflow portion 12 that supplies combustion air is formed between the casing 1 and the premixing cylinder 2, and the air inflow portion 12 is connected downstream of the air suction portion 11. Further, an air flow introduction portion 13 is provided in the vicinity of the end of the premixing tube 2 opposite to the side where the combustion tube 3 is connected to bend the direction in which the air flowing in from the air inflow portion 12 flows by approximately 180 °. The airflow introduction portion 13 is provided with a direction changing member 131 having a semicircular cross section.

  Further, the air flow introducing portion 13 is provided with a stay 132 that connects the casing 1 and the premixing cylinder 2. A plurality of stays 132 (for example, eight) are provided at equal central angular intervals. The stay 132 has one end 1321 on the casing 1 and the other end 1322 on the air introduction portion 13 side of the premixing cylinder 2. Connected to the end.

  The main premixing nozzle 5 is provided with a main fuel rod 51 for supplying fuel. Inside the main premixing nozzle 5, a premixing swirl vane 52 for generating a swirling flow that swirls the airflow flowing through the main premixing nozzle 5 around the main fuel rod 51 is provided. Further, on the upstream side of the premixed swirl vane 52, downstream fuel injection pegs 53 extending radially outward from the main fuel rod 51 are attached at equal central angular intervals. The downstream fuel injection peg 53 includes a plurality of fuel injection holes 531 for injecting fuel supplied from the main fuel rod 51.

  The main fuel rods 51 of the pilot nozzle 4 and the main premixing nozzle 5 pass through the end of the casing 1 of the combustor BS1, and supply fuel from the outside of the combustor BS1.

  A plurality of (for example, 16) first upstream fuel injection pegs 71a extending inward in the radial direction from the casing 1 and disposed at equal central angular intervals in the air inflow portion 12, and a first upstream fuel injection peg 71a A plurality of (for example, 16) second upstream fuel injection pegs 72a extending radially inward from the casing 1 and disposed at equal central angular intervals on the downstream side in the air flow direction. The first upstream fuel injection peg 71a and the second upstream fuel injection peg 72a include a plurality of fuel injection holes 73 for injecting fuel.

  Combustion air is supplied to the air intake portion 11 from the compressor. The combustion air supplied to the air suction part 11 is introduced into the air inflow part 12. By injecting fuel from the first upstream fuel injection peg 71a to the combustion air flowing into the air inflow portion 12, a very lean combustion air and fuel ultra-lean mixture is formed. Thereafter, the ultra lean mixture flows downstream through the air suction portion 12, and fuel is further injected into the lean mixture by the second upstream fuel injection peg 72 a provided on the downstream side.

  The lean air-fuel mixture is bent in the flow direction along the direction changing member 131 provided in the air flow introduction portion 13 and flows into the premixing cylinder 2. Most of the lean mixture that has flowed into the premixing cylinder 2 flows into the main premixing nozzle 5, a part of the remaining lean mixture is around the pilot nozzle 4, and the remaining lean mixture is pre-mixed with the premixing cylinder 2. It flows into the gap 6 of the main premixing nozzle 5.

  The lean air-fuel mixture that has flowed around the pilot nozzle 4 passes through the swirl vane 41. Thereafter, the fuel is injected in the combustion cylinder 3 together with the fuel injected from the fuel injection nozzle 42 to form a pilot flame.

  The lean air-fuel mixture flowing into the main premixing nozzle 5 flows along the main fuel rod 51 and injects fuel from a downstream fuel injection peg 53 provided on the main fuel rod 51. Thereafter, the premixed gas passes through the premixed swirl vane 52 to form a spiral airflow, and the fuel and air can be stirred so as to be uniform. The premixed gas flowing into the combustion cylinder 3 from the main premixing nozzle 5 comes into contact with the pilot diffusion flame to form the main flame Bn.

  The lean air-fuel mixture flowing into the gap 6 is blown onto the inner wall surface of the combustion cylinder 3 from the film cooling holes 61 formed on the downstream side of the gap 6 to form the cooling film Fi.

  After the fuel is injected by the first upstream fuel injection peg 71a and the second upstream fuel injection peg 72a to generate a lean mixture, the main premix nozzle 5 mixes the fuel to generate the premix Therefore, the uniformity of mixing of fuel and air can be increased. Here, since the lean air-fuel mixture is ejected from the film cooling hole 61 to form a cooling film, it is better that the fuel concentration is low. However, the present invention is not limited to this, but here, the first and second upstream fuel injection pegs 71a and 72a More injected fuel can be exemplified by about 10% to 30% of the total fuel input.

It is known that the combustion vibration generated in the combustion cylinder 3 is generated by the positional relationship between the upstream fuel injection peg and the downstream fuel injection peg 53 and the fuel injection amount. By dividing the fuel injection peg 71a and the second upstream fuel injection peg 72a, it is possible to prevent the occurrence of combustion vibration. The combustion vibration is currently considered as follows.
-Combustion oscillation is pressure fluctuation and flow velocity fluctuation.
-Even if the fuel supply is constant, if there is a fluctuation in speed, the concentration of the premixed gas can be increased or decreased.
・ Dense and dense waves are transmitted to the combustion zone along with the flow, generating new combustion vibrations.
・ The distance between the combustion area and the fuel supply position greatly affects the frequency and stability (difficulty of occurrence) of combustion vibration.
-Since combustion vibration occurs at various frequencies, there is no universally stable fuel injection position.
-With respect to the position along the air flow direction in which fuel is injected, it can be stabilized against various combustion vibration frequencies by installing it at multiple positions.

  FIG. 2 shows an axial sectional view of the internal structure of the combustor according to the present invention. The combustor BS2 shown in FIG. 2 has a second upstream fuel injection peg attached to a position different from that of the combustor BS1 shown in FIG. The other parts have substantially the same structure as the combustor BS1 shown in FIG. 1, and the substantially same parts are denoted by the same reference numerals.

  As shown in FIG. 2, the casing 1 and the premixing cylinder 2 of the combustor BS2 are connected by a stay 132, and the second upstream fuel injection peg 72b is connected to the air flow introduction portion 13 with the central axis of the premixing cylinder 2 The stays 132 are arranged in parallel so as to dodge. The second upstream fuel injection peg 72b is provided at the end 15 of the casing 1 and includes a plurality of fuel injection holes 73 through which fuel is injected.

  A fuel is injected from the first upstream fuel injection peg 71a to the combustion air flowing into the air inflow portion 12 to generate an ultra lean mixture. The ultra-lean air-fuel mixture flows into the air flow introduction unit 13 and is redirected by the direction changing member 131, and fuel is injected from the second upstream fuel injection peg 72b to become a lean air-fuel mixture. Thereafter, combustion gas is generated in the same manner as the combustor BS1 shown in FIG.

  FIG. 3 shows an enlarged view of the stay. The stay 133 shown in FIG. 3 has a hollow portion 1331 formed therein, and a fuel injection hole 1332 penetrating from the hollow portion 1331 to the outside. The fuel flows in the hollow portion 1331 of the stay 133, and the fuel can be injected from the fuel injection hole 1332 to generate a lean air-fuel mixture. By using the stay 133 formed in this way also as the second upstream fuel injection peg, the stay 133 can be used as the second upstream fuel injection peg, and the pressure loss at the air flow introducing portion 13 is increased accordingly. Can be suppressed.

  FIG. 4 is a sectional view in the axial direction of the internal structure of the combustor according to the present invention. The combustor BS3 shown in FIG. 4 has a second upstream fuel injection peg 72c attached to the upstream side of the main fuel rod 51 of the main premixing nozzle 5. Other than that, it has the same shape as the combustor BS1 shown in FIG. 1, and substantially the same parts are denoted by the same reference numerals.

  The second upstream fuel injection peg 72b of the combustor BS3 shown in FIG. 4 is upstream of the fuel injection peg 53 downstream of the main combustion rod 51 provided in the main premixing nozzle 5 inside the premixing cylinder 2. Are provided at equal central angular intervals.

  A lean mixture is generated by injecting fuel from the second upstream fuel injection peg 72c to the ultra lean mixture that has flowed into the premixing cylinder 2 from the air flow introduction portion 13 of the combustor BS3. Thereafter, combustion gas is generated in the same manner as the combustor BS1 shown in FIG.

  The attachment position of the second upstream fuel injection peg 72c is provided in the vicinity of the inlet of the main premixing nozzle 5, so that the air-fuel mixture flowing into the gap 6 between the main premixing nozzle 5 and the premixing cylinder 2 can be diluted more leanly. It can be. Thereby, a cooling film with a high cooling effect can be formed.

  Also, the provision of the second upstream fuel injection peg 72c makes it easier to reduce the concentration of the gap 6 than in the embodiment of FIGS. Usually, when an upstream nozzle is installed, it tends to be easy to backfire, but the embodiment of FIG. 4 has an advantage that backfire can be avoided. Further, the main fuel rod 51 and the fuel system can be integrated, so that the cost is reduced.

  FIG. 5 shows an axial sectional view of the internal structure of the combustor according to the present invention. The combustor BS4 shown in FIG. 5 has a first upstream fuel injection peg 71d attached to the air suction portion 11. Other than that, it has the same shape as the combustor BS1 shown in FIG. 1, and substantially the same parts are denoted by the same reference numerals.

  In the combustor BS4 shown in FIG. 5, a first upstream fuel injection peg 71d is attached to an air suction portion 11 for sucking combustion air. Fuel is injected from the first upstream fuel injection peg 71a into the combustion air sucked into the air suction portion 11 of the combustor BS4, and the combustion air becomes an ultra lean mixture. The ultra-lean air-fuel mixture flows along the inner wall of the casing 1 and flows into the air inflow portion 12. In the air inflow portion 12, the second upstream fuel injection peg 72a injects fuel into the ultra lean mixture, and the fuel is injected, whereby the ultra lean mixture becomes a lean mixture. Thereafter, combustion gas is generated in the same procedure as that of the combustor BS1 shown in FIG.

  In the combustor BS4 shown in FIG. 5, the second upstream fuel injection peg 71d provided in the air inflow portion 11 is adopted as the second upstream fuel injection peg, but is not limited thereto. As shown in FIGS. 2 and 4, the second upstream fuel injection peg 72 b provided in the air flow introducing portion 13 and the second fuel injection peg 72 b in the main fuel rod 51 of the main premixing nozzle 5 in the premixing cylinder 2 An upstream fuel injection peg 72c may be used.

  Both the first upstream fuel injection pegs 71a and 71d may be used. Further, two or more second upstream fuel injection pegs 72a, 72b, 72c may be provided. By arranging various types of upstream fuel injection pegs, combustion vibration can be prevented to a higher degree.

  In the above-described embodiments, the upstream fuel injection pegs are illustrated as being arranged in two stages. However, the present invention is not limited thereto, and the upstream fuel injection pegs arranged in two or more stages are illustrated. You may have. As the number of upstream fuel injection pegs increases, the concentration of the premixed gas becomes more uniform and can be stabilized with respect to many combustion vibration frequencies.

It is sectional drawing of an example of the combustor concerning this invention. It is sectional drawing of an example of the combustor concerning this invention. It is sectional drawing of an example of the stay which connects a casing and a premixing cylinder. It is sectional drawing of an example of the combustor concerning this invention. It is sectional drawing of an example of the combustor concerning this invention. It is sectional drawing of the conventional combustor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Casing 11 Air intake part 12 Air inflow part 13 Airflow introduction part 131 Direction change member 132 Stay 133 Stay 2 Premixing cylinder 3 Combustion cylinder 4 Pilot nozzle 41 Swirl vane 42 Fuel injection hole 5 Main premixing nozzle 51 Main fuel rod 52 Preliminary Mixed swirl vane 53 Downstream fuel injection peg 6 Gap 61 Film cooling holes 71a, 71d First upstream fuel injection pegs 72a, 72b, 72c Second upstream fuel injection pegs BS1-BS4 Combustor Bn Main flame

Claims (8)

A combustor for supplying combustion gas to a gas turbine,
A casing,
A cylindrical premixing cylinder provided inside the casing;
A combustion cylinder communicating with the premixing cylinder;
An air flow introducing portion for changing the direction of the air flow flowing through the air inflow portion and introducing the air flow into the premixing cylinder;
A pilot nozzle provided on the central axis of the premixing cylinder;
A main premixing nozzle that extends substantially parallel to the pilot nozzle and is provided at equal central angular intervals in the premixing cylinder,
The main premixing nozzle has a fuel rod for flowing fuel on a central axis, and a downstream fuel injection peg attached to the fuel rod at equal central angular intervals and extending radially outward.
A combustor comprising upstream fuel injection pegs arranged in a plurality of stages along an air flow direction on an upstream side of the premixing cylinder. There is a gap between the casing and the premixing cylinder, and an air inflow portion for supplying combustion air is formed,
2. The combustor according to claim 1, wherein at least one of the upstream fuel injection pegs arranged in the plurality of stages is provided in the air inflow portion and extends from the casing toward the premixing cylinder. . An air suction part for allowing combustion air to flow into the casing is provided on the upstream side of the air inflow part,
The combustor according to claim 1 or 2, wherein at least one of the upstream fuel injection pegs arranged in the plurality of stages is provided in the air suction portion.   3. The upstream fuel injection pegs arranged in the plurality of stages, wherein at least one stage extends radially inward from the casing and is provided at equal central angular intervals. Item 4. The combustor according to Item 3.   The at least one stage among the upstream side fuel injection pegs arranged in the plurality of stages is provided at an equal center angle interval substantially parallel to the central axis of the premixing cylinder at a folded portion of the airflow. The combustor according to any one of claims 1 to 4. The casing is provided with stays attached at equal central angular intervals and connected to the premixing cylinder,
The stay has a hollow portion through which fuel flows and a fuel injection hole penetrating from the hollow portion to the outside on the surface, and serves as one stage of the upstream fuel injection peg arranged in the plurality of stages. The combustor according to any one of claims 1 to 5, wherein the combustor is used.   The at least one stage among the upstream side fuel injection pegs arranged in the plurality of stages is attached to the fuel rod at equal central angular intervals and extends outward in the radial direction. The combustor described in.   8. The upstream fuel injection peg is a two-stage upstream fuel injection peg having two stages, a first upstream fuel injection peg and a second upstream fuel injection peg. A combustor according to any one of the above.

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