Gas turbine combustor, gas turbine, control device, and control method

To provide a gas turbine combustor that can suppress a generation amount of NOx and maintain a flame holding property, while suppressing burn damage around a pilot nozzle including the pilot nozzle. A gas turbine combustor includes a pilot nozzle that can inject fuel F and cooling air A for cooling a nozzle tip, a flow regulating valve that can adjust a flow rate of cooling air to be supplied to the pilot nozzle, a detection sensor that detects a combustion state of fuel, and a control device that controls the flow regulating valve based on a detection result of the detection sensor.

FIELD

The present invention relates to a gas turbine combustor including an injection nozzle, a gas turbine including a gas turbine combustor, and a control device and a control method for a gas turbine combustor.

BACKGROUND

A general gas turbine is configured by a compressor, a combustor, and a turbine. Air taken in from an air inlet is compressed by a compressor, thereby becoming high-temperature and high-pressure compressed air. The combustor supplies fuel to the compressed air to burn the fuel, thereby acquiring high-temperature and high-pressure combustion gas (a working fluid). The turbine is driven by the combustion gas to drive a generator connected to the turbine.

In a conventional gas turbine combustor, a plurality of main combustion burners are arranged so as to surround a circumference of a pilot combustion burner, a pilot nozzle is incorporated in the pilot combustion burner, and a main nozzle is incorporated in the main combustion burners. The pilot combustion burner and the main combustion burners are arranged inside of an inner cylinder of the gas turbine.

As such a gas turbine combustor, there are gas turbine combustors described in Patent Literatures 1 and 2. A gas turbine combustor described in Patent Literature 1 has a configuration such that a sleeve is arranged outside of a body that forms a fuel passage, a cover ring is arranged therebetween to form an air passage inside and outside thereof, and a nozzle chip having a fuel injection hole that communicates with the fuel passage is provided at an apical end of the cover ring to configure a pilot nozzle. A gas turbine combustor described in Patent Literature 2 has a configuration such that a diffusion chip, which is a passage through which fuel, air, or an air-fuel mixture passes to function together with main and auxiliary mixing circuits, is provided in a fuel nozzle.

CITATION LIST

Patent Literatures

Patent Literature 1: Japanese Patent Application Laid-open No. 2009-168397 A

Patent Literature 2: Japanese Patent Application Laid-open No. 2010-159757 A

SUMMARY

Technical Problem

When fuel is injected from main nozzles and is combusted, circulating flow is formed by swirling flow and circulating flow of high-temperature gas (hot gas) flows into a space opposite to a nozzle tip of a pilot nozzle. Cooling air is injected to the circulating flow from the pilot nozzle. At this time, an injection amount of fuel injected from the main nozzles and the pilot nozzle changes depending on an output of a gas turbine. Therefore, a forming position of the circulating flow of the high-temperature gas approaches to the pilot nozzle or moves away therefrom and the forming position of the circulating flow becomes unstable. If the circulating flow approaches too much to the pilot nozzle, the temperature around the pilot nozzle including the pilot nozzle increases, and thus the nozzle tip of the pilot nozzle may be burn damaged and a generation amount of NOx also increases. On the other hand, if the circulating flow is too far away from the pilot nozzle, the flame holding property deteriorates and combustion becomes unstable. Further, due to a decrease of combustibility, generation of CO and unburnt combustible contents increases. Depending on the arrangement of the pilot nozzle and the main nozzles, the circulating flow of the high-temperature gas may be formed on the nozzle tip side of the main nozzles. Therefore, the main nozzles have a problem similar to that of the pilot nozzle.

Therefore, an object of the present invention is to provide a gas turbine combustor, a gas turbine, a control device, and a control method that can suppress the generation amount of NOx and maintain the flame holding property, while suppressing burn damage around an injection nozzle including the injection nozzle.

Solution to Problem

In one aspect, there is provided a gas turbine combustor comprising: an injection nozzle that can inject fuel and cooling air for cooling a nozzle tip; an air flow-rate adjustment unit that can adjust a flow rate of the cooling air to be supplied to the injection nozzle; a detection unit that detects a combustion state of the fuel; and a control device that controls the air flow-rate adjustment unit based a detection result of the detection unit.

According to this configuration, the control device can control the air flow-rate adjustment unit to adjust the flow rate of the cooling air to be injected from the injection nozzle. Therefore, a forming position of a circulating flow that flows into the front of the injection nozzle can be adjusted to an appropriate forming position according to the flow rate of the cooling air. Accordingly, it is possible to suppress the generation amount of NOx and maintain the flame holding property, while suppressing burn damage around the injection nozzle including the injection nozzle. As the detection unit that detects the combustion state of the fuel, for example, there can be mentioned an NOx detection sensor that detects the generation amount of NOx generated depending on the combustion state of the fuel, a temperature sensor that detects the temperature of a member that changes depending on the combustion state of the fuel, and a pressure sensor that detects pressure fluctuations in the combustor, which is caused depending on the combustion state of the fuel. The flow rate of the cooling air can be adjusted through the control device depending on an output of the gas turbine or an operating state quantity such as fuel proportion. Further, the injection nozzle can be the pilot nozzle or the main nozzle, and is not particularly limited.

In one aspect, the gas turbine combustor further comprises a cooling-air supply flow channel connected to the injection nozzle to supply the cooling air toward the injection nozzle, wherein the air flow-rate adjustment unit has a flow regulating valve provided in the cooling-air supply flow channel.

According to this configuration, the control device can easily adjust the flow rate of the cooling air to be injected from the injection nozzle by adjusting an opening degree of the flow regulating valve.

In one aspect, the gas turbine combustor further comprises a cooling-air supply flow channel connected to the injection nozzle to supply the cooling air toward the injection nozzle, wherein the air flow-rate adjustment unit has a compressor that supplies the cooling air toward the cooling-air supply flow channel.

According to this configuration, the control device can easily adjust the flow rate of the cooling air to be injected from the injection nozzle by controlling actuation of the compressor.

In one aspect, the injection nozzle includes a plurality of internal flow channels formed therein from a nozzle base end side to a nozzle tip side, through which the fuel and the cooling air can circulate respectively, the plurality of internal flow channels include a first fuel flow channel through which the fuel circulates toward the nozzle tip, a second fuel flow channel through which the fuel circulates toward the nozzle tip, and a cooling flow channel through which the cooling air circulates toward the nozzle tip, and the cooling flow channel is provided between the first fuel flow channel and the second fuel flow channel in a direction from an internal side toward an external side of the injection nozzle.

According to this configuration, because the cooling passage can be arranged between the first fuel gas passage and the second fuel gas passage, the cooling air can be effectively introduced to the nozzle tip depending on the shape of the injection nozzle.

In one aspect, the injection nozzle includes a plurality of internal flow channels formed therein from a nozzle base end side to a nozzle tip side, through which the fuel and the cooling air can circulate respectively, a contraction portion formed by narrowing down a part of at least one of the internal flow channels, a manifold formed on an apical end side of the contraction portion to communicate with the internal flow channel, and an injection hole that communicates with the manifold, wherein one part of the plurality of internal flow channels is a cooling flow channel through which the cooling air circulates toward the nozzle tip side.

According to this configuration, the injection nozzle can circulate the fuel and the cooling air respectively depending on the internal flow channels. Therefore, the fuel and the cooling air circulating in the internal flow channels are not mixed with each other. Further, the fuel and the cooling air circulating in the internal flow channels pass through the contraction portion. Therefore, a circulation amount of the fuel and the cooling air flowing toward the nozzle tip side is stabilized, thereby enabling to stabilize the injection amount of the fuel and the cooling air to be injected from the injection holes. The fuel and the cooling air having passed through the contraction portion pass through the manifold and are injected from the injection holes. Therefore, the fuel and the cooling air injected from the injection holes via the manifold are injected with a uniform pressure. For example, by forming the manifold in a circumferential direction and forming a plurality of injection holes in the circumferential direction along the manifold, the fuel and the cooling air injected from the injection holes can be injected with a uniform pressure in the circumferential direction.

The injection nozzle includes a nozzle body provided to extend from the nozzle base end side toward the nozzle tip side, and a plurality of swirler vanes arranged and provided around the nozzle body with a predetermined gap therebetween, and in the plurality of internal flow channels, the cooling flow channel, which is the part of the internal flow channels, is provided to extend from the nozzle base end side toward the nozzle tip side, and a fuel flow channel through which the fuel circulates, which is the other part of the internal flow channels, is provided to extend from the nozzle base end side toward the swirler vanes.

According to this configuration, the cooling air can be injected from an apical end side of the nozzle body, and the fuel can be injected from the plurality of swirler vanes.

In one aspect, the injection nozzle includes a nozzle body provided to extend from the nozzle base end side toward the nozzle tip side, and a film-air flow channel formed around the nozzle body, through which film air circulates from the nozzle base end side toward the nozzle tip side.

According to this configuration, the film air flow channel can be formed around the nozzle body.

In one aspect, the film-air flow channel communicates with an external flow channel formed outside of the nozzle body.

According to this configuration, the air taken in from the external flow channel can be used as the film air.

In one aspect, one part of the plurality of internal flow channels is the film-air flow channel provided to extend from the nozzle base end side toward the nozzle tip side.

According to this configuration, the film air flow channel can be formed as the internal flow channel of the nozzle body.

In one aspect, the cooling flow channel is provided inside of the injection nozzle with respect to the film-air flow channel.

According to this configuration, the cooling flow channel can be formed inside of the film air flow channel.

In one aspect, there is provided a gas turbine combustor comprising: a pilot nozzle, and main nozzles provided around the pilot nozzle, wherein as the pilot nozzle, the injection nozzle according to any one of claims1to10is applied.

According to this configuration, the fuel and the cooling air can be injected from the pilot nozzle. At this time, because the pilot nozzle can inject the cooling air from the nozzle tip side, the forming position of the circulating flow that flows into the front of the pilot nozzle can be adjusted to an appropriate forming position depending on the flow rate of the cooling air.

In one aspect, there is provided a gas turbine comprising: the gas turbine combustor according to any one of claims1to11, and a turbine that is rotated by combustion gas generated by combusting the fuel in the gas turbine combustor.

According to this configuration, the generation amount of NOx can be suppressed and the flame holding property can be maintained, while suppressing burn damage around the injection nozzle including the injection nozzle of the gas turbine combustor. Therefore, combustion by the gas turbine combustor can be stably performed, and as a result, turbine efficiency can be improved by stable combustion.

In one aspect, there is provided a control device for a gas turbine combustor that includes an injection nozzle that can inject fuel and cooling air for cooling a nozzle tip, an air flow-rate adjustment unit that can adjust a flow rate of the cooling air to be supplied to the injection nozzle, and a detection unit that detects a combustion state of the fuel, wherein the control device controls the air flow-rate adjustment unit based on a detection result of the detection unit.

In one aspect, there is provided a control method for a gas turbine combustor that includes an injection nozzle that can inject fuel and cooling air for cooling a nozzle tip, an air flow-rate adjustment unit that can adjust a flow rate of the cooling air to be supplied to the injection nozzle, and a detection unit that detects a combustion state of the fuel, wherein the air flow-rate adjustment unit is controlled based on a detection result of the detection unit.

According to this configuration, the flow rate of the cooling air to be injected from the injection nozzle can be adjusted by controlling the air flow-rate adjustment unit. Therefore, the forming position of the circulating flow that flows into the front of the injection nozzle can be adjusted to an appropriate forming position depending on the flow rate of the cooling air.

DESCRIPTION OF EMBODIMENTS

Exemplary embodiments of the present invention will be explained below in detail with reference to the accompanying drawings. The present invention is not limited to the embodiments. In addition, constituent elements in the embodiments described below include those that can be easily replaced or assumed by persons skilled in the art, or that are substantially equivalent. Further, the constituent elements described below can be appropriately combined and when there are a plurality of embodiments, these embodiments can also be combined.

First Embodiment

FIG. 1is a schematic configuration diagram illustrating a gas turbine according to a first embodiment.FIG. 2is a schematic configuration diagram illustrating a gas turbine combustor according to the first embodiment.FIG. 3is a sectional view of relevant parts in the gas turbine combustor according to the first embodiment.FIG. 4is a sectional view illustrating an apical end of a pilot nozzle according to the first embodiment.FIG. 5is a schematic diagram illustrating the gas turbine according to the first embodiment.

A gas turbine1according to the first embodiment is configured, as illustrated inFIG. 1andFIG. 5, by a compressor11, a combustor (gas turbine combustor)12, and a turbine13. A power generator14(seeFIG. 5) is connected to the gas turbine1so as to be able to generate power.

The compressor11has an air inlet20that takes in air. An inlet guide vane (IGV)22is arranged in a compressor casing21, a plurality of compressor vanes23and turbine blades24are alternately arranged in a front-back direction (an axial direction of a rotor32described later), and a bleed air chamber25is provided outside thereof. By supplying fuel to compressed air compressed by the compressor11and igniting the fuel, the combustor12can combust the fuel. In the turbine13, a plurality of turbine vanes27and turbine blades28are alternately arranged in the front-back direction (the axial direction of the rotor32described later) in a turbine casing26. On a downstream side of the turbine casing26, an exhaust chamber30is arranged via an exhaust casing29, and the exhaust chamber30has an exhaust diffuser31connected to the turbine13.

The rotor (a rotary shaft)32is positioned so as to penetrate a central portion of the compressor11, the combustor12, the turbine13, and the exhaust chamber30. While an end of the rotor32on the side of the compressor11is supported rotatably by a bearing33, an end thereof on the side of the exhaust chamber30is rotatably supported by a bearing34. In the rotor32, a plurality of disks attached with the respective turbine blades24are overlapped on each other and fixed in the compressor11, and a plurality of disks attached with the respective turbine blades28are overlapped on each other and fixed in the turbine13, and a drive shaft of the power generator14is connected to an end of the turbine13on the side of the compressor11.

In the gas turbine1, the compressor casing21of the compressor11is supported by a leg portion35, the turbine casing26of the turbine13is supported by a leg portion36, and the exhaust chamber30is supported by a leg portion37.

Therefore, air taken in from the air inlet20of the compressor11passes through the inlet guide vane22and the plurality of compressor vanes23and turbine blades24and is compressed, to become high-temperature and high-pressure compressed air. The combustor12supplies predetermined fuel to the compressed air to combust the fuel. Because high-temperature and high-pressure combustion gas that is a working fluid generated by the combustor12passes through the plurality of turbine vanes27and turbine blades28constituting the turbine13, the rotor32is driven and rotated thereby driving the power generator14connected to the rotor32. Meanwhile, the combustion gas that has driven the turbine13passes through the exhaust diffuser31and is discharged from the exhaust chamber30to the air as flue gas.

In the combustor12described above, as illustrated inFIG. 2, a combustor inner cylinder42is arranged inside of a casing41with a predetermined gap therebetween, and a combustor transition piece43is connected to an apical end of the combustor inner cylinder42. In the combustor inner cylinder42, a pilot combustion burner44is arranged to be positioned at an inside central part thereof and a plurality of main combustion burners45are arranged so as to surround the pilot combustion burner44in a circumferential direction on an inner periphery of the combustor inner cylinder42. The combustor transition piece43is connected with a bypass pipe46and a bypass valve47is provided on the bypass pipe46.

A top hat portion54is fitted to the casing41and is fastened by a plurality of fastening bolts55. The combustor inner cylinder42is arranged inside of the casing41with a predetermined gap therebetween, and an air passage56in a cylindrical shape is formed between an inner surface of the top hat portion54and an outer surface of the combustor inner cylinder42. The air passage56communicates with a supply passage57of the compressed air compressed by the compressor11at one end thereof and communicates with a base end side of the combustor inner cylinder42at the other end thereof. The combustor inner cylinder42has a large-diameter portion42aformed on the base end side, and thus the air passage56has a bell-mouth shape.

The pilot combustion burner44is arranged in the combustor inner cylinder42, positioned in the central part thereof, and the plurality of main combustion burners45are arranged around the pilot combustion burner44. The pilot combustion burner44is configured by a pilot cone58supported by the combustor inner cylinder42and a pilot nozzle59arranged inside of the pilot cone58, and swirler vanes60are provided on an outer periphery of the pilot nozzle59. Each of the main combustion burners45is configured by a burner cylinder61and a main nozzle62arranged inside of the burner cylinder61, and swirler vanes63are provided on an outer periphery of the main nozzle62.

The top hat portion54is provided with fuel ports64and65, a pilot fuel line (not illustrated) is connected to the fuel port64of the pilot nozzle59and a main fuel line (not illustrated) is connected to the fuel port65of each of the main nozzles62. Although not illustrated herein, the top hat portion54is provided with a cooling-air supply port66(seeFIG. 5). As illustrated inFIG. 5, the cooling-air supply port66is connected to a branch passage (cooling-air supply flow channel)67branched from the supply passage57extending from the compressor11to the gas turbine combustor12. That is, the supply passage57communicates with the air passage56in the gas turbine combustor12, and the branch passage67branched from the supply passage57is connected to the cooling-air supply port66of the gas turbine combustor12.

Therefore, as illustrated inFIG. 2,FIG. 3, andFIG. 5, the high-temperature and high-pressure compressed air flows into the air passage56and the branch passage67from the supply passage57, flows into the combustor inner cylinder42from the air passage56, and also flows into the cooling-air supply port66from the branch passage67. In the combustor inner cylinder42, the compressed air is mixed with the fuel injected from the main combustion burners45to become a swirling flow of a premixed air-fuel mixture and flows into the combustor transition piece43. Further, in the combustor inner cylinder42, the compressed air is mixed with the fuel injected from the pilot combustion burner44, ignited by a pilot burner (not illustrated) and combusted to become combustion gas, and is ejected into the combustor transition piece43. At this time, a part of the combustion gas is ejected so as to be diffused circumferentially inside of the combustor transition piece43with flames and combusted by being ignited by the premixed air-fuel mixture flowing into the combustor transition piece43from each of the main combustion burners45. That is, flame holding for performing stable combustion of lean premixed fuel from the main combustion burners45is enabled by pilot flames by means of the pilot fuel injected from the pilot combustion burner44.

A high-temperature circulating flow is generated in the pilot cone58due to combustion of the main fuel. The circulating flow opposingly flows into the front of the pilot nozzle59. The forming position of the circulating flow is changed in a direction approaching to and moving away from the pilot nozzle59due to the cooling air injected from the pilot nozzle59. At this time, the compressed air flowing into the cooling-air supply port66is used as cooling air for cooling the pilot nozzle59.

The pilot nozzle59according to the first embodiment is described next in detail with reference toFIG. 4. At an apical end of the pilot nozzle59, as illustrated inFIG. 4, a nozzle body71has a hollow cylindrical shape, and swirler vanes60are provided around the nozzle body71. A plurality of internal flow channels are formed inside the nozzle body71, and a first fuel passage72, a second fuel passage74, and a cooling passage73are formed as the internal flow channels.

The second fuel passage74is formed at the center of the shaft inside of the nozzle body71and is formed from a base end side to an apical end side thereof. The base end side of the second fuel passage74communicates with the fuel port64, and fuel F supplied from the fuel port64passes through the second fuel passage74and is injected from the apical end of the nozzle body71.

The cooling passage73is formed on an outer peripheral side of the second fuel passage74inside the nozzle body71and is formed from the bottom end side to the apical end side thereof. The cooling passage73communicates with the cooling-air supply port66on the bottom end side, and the compressed air flowing into the cooling-air supply port66from the compressor11via the supply passage57and the branch passage67circulates therethrough as cooling air A.

The first fuel passage72is formed on an outer peripheral side of the cooling passage73inside the nozzle body71and is formed from the bottom end side along the inside of the swirler vanes60. The first fuel passage72communicates with the fuel port64on the bottom end side and with a first fuel injection hole75formed in the swirler vane60on the apical end side. Therefore, the fuel F supplied from the fuel port64passes through the first fuel passage72and is injected from the first fuel injection hole75formed in the swirler vane60.

In this manner, the cooling passage73is provided between an inner side of the first fuel passage72and an outer side of the second fuel passage74in a radial direction of the nozzle body71. The fuel F1circulating in the first fuel passage72and fuel F2circulating in the second fuel passage74contain fuel gas such as LNG, and become an air-fuel mixture of fuel gas and compressed air (pilot fuel).

The cooling passage73is connected to the supply passage57via the branch passage67and the branch passage67is provided with a flow regulating valve (air flow-rate adjustment unit)77. The flow regulating valve77is connected to a control device91provided in the gas turbine1. An opening degree of the flow regulating valve77is adjusted by the control device91. An apical end of the cooling passage73communicates with air injection holes79formed in the apical end of the nozzle body71. The air injection holes79are directed inward of the nozzle body71to inject the cooling air A to the inner side of the nozzle body71toward the front of the nozzle body71.

An apical end of the second fuel passage74communicates with a second fuel injection holes78formed at the apical end of the nozzle body71. The second fuel injection holes78are directed outward of the nozzle body71to inject the fuel F2to the outer side of the nozzle body71toward the front of the nozzle body71.

In this manner, the pilot nozzle59can inject the fuel F1from the first fuel injection holes75in the swirler vanes60and the fuel F2from the second fuel injection holes78of the nozzle body71. That is, the pilot nozzle59can inject the fuel F1and the fuel F2selectively or simultaneously. Further, the pilot nozzle59injects the cooling air A from the air injection holes79of the nozzle body71.

As described above, the bottom end of the cooling passage73is connected to the branch passage67via the cooling-air supply port66and the branch passage67is provided with the flow regulating valve77. The control device91controls the flow regulating valve77depending on the operating state of the gas turbine1, to adjust the flow rate of the cooling air A circulating in the branch passage67, thereby adjusting the injection amount of the cooling air A to be injected from the air injection holes79.

Specifically, if the forming position of the circulating flow in the pilot cone58is close to the pilot nozzle59, the control device91increases the opening degree of the flow regulating valve77to increase the injection amount of the cooling air A to be injected into the pilot cone58. On the other hand, if the forming position of the circulating flow in the pilot cone58is away from the pilot nozzle59, the control device91decreases the opening degree of the flow regulating valve77to decrease the injection amount of the cooling air A to be injected into the pilot cone58. That is, the control device91adjusts the opening degree of the flow regulating valve77according to the operating state of the gas turbine1(a combustion state of the fuel F).

In the first embodiment, a detection sensor92that detects the operating state of the gas turbine1is provided, and the detection sensor92is connected to the control device91. As the detection sensor92, for example, an NOx detection sensor that detects a generation amount of NOx generated depending on the combustion state of the fuel F, a gas-component detection sensor92athat detects CO generated depending on the combustion state of the fuel F or unburnt hydrocarbon, a temperature sensor92bthat detects the temperature of members constituting the gas turbine combustor12that changes depending on the combustion state of the fuel F, or a pressure sensor92cthat detects pressure fluctuations in the combustor inner cylinder42can be applied. The control device91adjusts the opening degree of the flow regulating valve77based on a detection result of the detection sensor92. The opening degree of the flow regulating valve77(that is, the flow rate of the cooling air A) can be adjusted by the control device91according to the operating state quantity such as an output of the gas turbine or fuel proportion.

Specifically, when the detection sensor92is the pressure sensor92c, the control device91decreases the opening degree of the flow regulating valve77along with an increase of the pressure fluctuations detected by the pressure sensor92c, thereby decreasing the injection amount of the cooling air A from the air injection holes79.

When the detection sensor92is the temperature sensor92band if the temperature detected by the temperature sensor92bis higher than a preset set temperature, the control device91increases the opening degree of the flow regulating valve77to increase the injection amount of the cooling air A from the airinjection holes79.

The detection sensor92can be any sensor that can detect the operating state of the gas turbine1, that is, the combustion state of the fuel F.

Combustion in the pilot nozzle59according to the first embodiment is described next. In the pilot nozzle59, as illustrated inFIG. 4, the air-fuel mixture (fuel) F1injected from the first fuel injection holes75in the swirler vanes60and the air-fuel mixture (fuel) F2injected from the second fuel injection holes78of the nozzle body71are ignited by a pilot burner (not illustrated) and combusted to become high-temperature combustion gas, and ejected so as to be diffused circumferentially with flames. Further, the cooling air A passing through the cooling passage73is injected to the inner side of the nozzle body71, thereby adjusting the forming position of the circulating flow by the cooling air A.

At this time, the control device91adjusts the opening degree of the flow regulating valve77based on the detection result of the detection sensor92to adjust the injection amount of the cooling air A to be injected from the air injection holes79to the pilot cone58. Therefore, if the circulating flow approaches the pilot nozzle59, the injection amount of the cooling air A injected from the air injection holes79is increased, thereby enabling to keep away the forming position of the circulating flow flowing into the front of the pilot nozzle59rearward by the increased cooling air A. On the other hand, if the circulating flow is away from the pilot nozzle59, the injection amount of the cooling air A injected from the air injection holes79is decreased, thereby enabling to move the forming position of the circulating flow flowing into the front of the pilot nozzle59close to the pilot nozzle59by the decreased cooling air A. In this manner, the control device91can adjust the forming position of the circulating flow by adjusting the flow regulating valve77.

As described above, according to the first embodiment, the control device91can adjust the injection amount of the cooling air A to be injected from the pilot nozzle59by controlling the flow regulating valve77based on the detection result of the detection sensor92. Therefore, the forming position of the circulating flow flowing into the front of the pilot nozzle59can be adjusted to an appropriate forming position by the flow rate of the cooling air A. Accordingly, the generation amount of NOx, CO, or unburnt combustible contents can be suppressed and the flame holding property can be maintained, while suppressing burn damage around the pilot nozzle59including the pilot nozzle59.

According to the first embodiment, the control device91can adjust the flow rate of the cooling air A to be injected from the pilot nozzle59easily by adjusting the opening degree of the flow regulating valve77.

Furthermore, according to the first embodiment, because the cooling passage73can be arranged between the first fuel passage72and the second fuel passage74, the cooling air A can be effectively supplied to the nozzle tip depending on the shape of the pilot nozzle59.

Second Embodiment

A gas turbine combustor110according to a second embodiment is described next with reference toFIG. 6.FIG. 7is a schematic diagram illustrating a gas turbine according to the second embodiment. In the second embodiment, to avoid redundant explanations, portions different from those of the first embodiment are described, and portions having identical configurations as those of the first embodiment are denoted and described by like reference signs. In the first embodiment, the control device91controls the flow regulating valve77, thereby adjusting the flow rate of the cooling air A circulating in the cooling passage73. In the second embodiment, a compressor111is provided instead of the flow regulating valve77, and the control device91controls the compressor111to adjust the flow rate of the cooling air A circulating in the cooling passage73.

As illustrated inFIG. 6, in the gas turbine combustor110according to the second embodiment, the bottom end of the cooling passage73is connected to the branch passage67via the cooling-air supply port66, and the compressor111is provided in the branch passage67. An inflow port side of the compressor111is connected to the side of the compressor11and an outflow port side thereof is connected to the side of the gas turbine combustor110. The control device91controls the compressor111depending on the operating state of the gas turbine1to adjust the flow rate of the cooling air A circulating in the branch passage67, thereby adjusting the injection amount of the cooling air A to be injected from the air injection holes79. Specifically, if the forming position of the circulating flow in the pilot cone58is close to the pilot nozzle59, the control device91increases the number of revolutions of the compressor111to increase the injection amount of the cooling air A to be injected into the pilot cone58. On the other hand, if the forming position of the circulating flow in the pilot cone58is away from the pilot nozzle59, the control device91decreases the number of revolutions of the compressor111to decrease the injection amount of the cooling air A to be injected into the pilot cone58. That is, the control device91adjusts the number of revolutions of the compressor111according to the operating state of the gas turbine1(the combustion state of the fuel F).

As described above, according to the second embodiment, the control device91can adjust the flow rate of the cooling air A to be injected from the pilot nozzle59by controlling the compressor111based on the detection result of the detection sensor92. Therefore, the forming position of the circulating flow flowing into the front of the pilot nozzle59can be adjusted to an appropriate forming position by the flow rate of the cooling air A. Accordingly, the generation amount of NOx, CO, or unburnt combustible contents can be suppressed and the flame holding property can be maintained, while suppressing burn damage around the pilot nozzle59including the pilot nozzle59.

Furthermore, according to the second embodiment, the control device91can adjust the injection amount of the cooling air A to be injected from the pilot nozzle59easily by controlling the actuation of the compressor111. At this time, as compared to the case where the flow regulating valve77is provided in the branch passage67as in the first embodiment, the pressure in the cooling passage73can be increased, thereby enabling to adjust the injection amount of the cooling air A in a wider range.

In the second embodiment, the flow regulating valve77according to the first embodiment is omitted. However, the flow regulating valve77can be provided in the branch passage67on the downstream side of the compressor111. In this case, the control device91adjusts the injection amount of the cooling air A by appropriately controlling the flow regulating valve77and the compressor111.

In the first and second embodiments, the first fuel passage72, the second fuel passage74, and the respective cooling passages73are provided inside of the pilot nozzle59. However, the configuration is not limited thereto, and a plurality of internal flow channels can be formed appropriately depending on the type or the like of the fuel F to be used or the gas turbine combustor12or110.

Third Embodiment

A gas turbine combustor120according to a third embodiment is described next with reference toFIG. 7.FIG. 7is a sectional view illustrating an apical end of a pilot nozzle according to the third embodiment. In the third embodiment also, to avoid redundant explanations, portions different from those of the first and second embodiments are described, and portions having identical configurations as those of the first and second embodiments are denoted and described by like reference signs. In the first and second embodiments, the pilot nozzle59illustrated inFIG. 4is applied as the pilot nozzle. In the third embodiment, a pilot nozzle121illustrated inFIG. 7is applied.

The pilot nozzle121according to the third embodiment can inject as fuel, the fuel gases F1and F2and fuel oil F3selectively or simultaneously. Therefore, the fuel port64communicating with the pilot nozzle121is configured to include a line for supplying the fuel oil F3and lines for supplying the fuel gases F1and F2, so that the fuel gases F1and F2and the fuel oil F3can be supplied toward the pilot nozzle121. The pilot nozzle121according to the third embodiment is specifically described with reference toFIG. 7.

As illustrated inFIG. 7, the pilot nozzle121has a nozzle body171and a sleeve182provided on an outer periphery of the nozzle body171on an apical end side thereof. A plurality of swirler vanes160identical to those of the first embodiment are arranged and provided around the nozzle body171with a predetermined gap therebetween in a circumferential direction.

The nozzle body171has a hollow cylindrical shape and a plurality of internal flow channels are formed inside the nozzle body171, and a first fuel gas passage173, a second fuel gas passage172, a cooling passage174, a fuel oil passage175, and a water passage176are formed as the internal flow channels.

The fuel oil passage175is formed at the center of the shaft inside of the nozzle body171and is formed from a base end side to an apical end side thereof. The base end side of the fuel oil passage175communicates with the fuel port64, and the fuel oil F3that flows in via the fuel port64circulates therethrough. The apical end side of the fuel oil passage175communicates with a fuel-oil injection portion185formed at the center of the apical end of the nozzle body171. The fuel-oil injection portion185is formed at the center of the apical end of the nozzle body171and injects the fuel oil F3toward the front of the nozzle body171.

The water passage176is formed in a cylindrical shape along an outer periphery of the fuel oil passage175inside the nozzle body171and is formed from the base end side to the apical end side thereof. A base end side of the water passage176is connected to a water supply source (not illustrated), and water W supplied from the water supply source circulates therethrough. An apical end side of the water passage176communicates with a water injection hole186formed at the apical end of the nozzle body171. The water injection hole186is formed in a plurality of numbers to be arranged with a predetermined gap therebetween in the circumferential direction along an outer periphery of the fuel-oil injection portion185at the apical end of the nozzle body171. Each of the water injection holes186is directed inward (toward the center) of the nozzle body171and injects the water W to the inner side of the nozzle body171toward the front of the nozzle body171.

The cooling passage174is formed on an outer peripheral side of the water passage176inside the nozzle body171, and is formed from the base end side to the apical end side thereof. A base end side of the cooling passage174communicates with the cooling-air supply port66and compressed air that flows in from the compressor11via the cooling-air supply port66circulates therethrough as the cooling air A. An apical end side of the cooling passage174communicates with an air injection hole187formed at the apical end of the nozzle body171. The air injection hole187is formed in a plurality of numbers to be arranged with a predetermined gap therebetween in the circumferential direction along an outer periphery of the water injection holes186at the apical end of the nozzle body171. Each of the air injection holes187is directed inward of the nozzle body171and injects the cooling air A to the inner side of the nozzle body171toward the front of the nozzle body171.

The first fuel gas passage173is formed on the outer peripheral side of the water passage176inside the nozzle body171, and is provided in parallel with the cooling passage174along the circumferential direction and is formed from the base end side to the apical end side of the nozzle body171. A base end side of the first fuel gas passage173communicates with the fuel port64and the fuel gas F1that flows in via the fuel port64circulates therethrough. An apical end side of the first fuel gas passage173communicates with a first fuel-gas injection hole188formed at the apical end of the nozzle body171. The first fuel-gas injection hole188is formed in a plurality of numbers to be arranged with a predetermined gap therebetween in the circumferential direction along an outer periphery of the air injection hole187, at the apical end of the nozzle body171. Each of the first fuel-gas injection holes188is directed outward of the nozzle body171to inject the fuel gas F1to the outer side of the nozzle body171toward the front of the nozzle body171.

The second fuel gas passage172is formed on the outer peripheral side of the cooling passage174and the first fuel gas passage173inside the nozzle body171, and is formed from the base end side of the nozzle body171along the inside of the swirler vanes160. A base end side of the second fuel gas passage172communicates with the fuel port64and the fuel gas F2that flows in via the fuel port64circulates therethrough. An apical end side of the second fuel gas passage172communicates with a plurality of second fuel-gas injection holes189formed in the plurality of swirler vanes160. The second fuel-gas injection holes189inject the fuel gas F2toward the front of the swirler vanes160.

In this manner, the respective injection holes (injection portions)185,186,187,188, and189are formed so that the injection directions of the fluids such as the fuel gas F1, the fuel gas F2, the fuel oil F3, the cooling air A, and the water W are made different.

The sleeve182is formed in a cylindrical shape along the outer periphery of the nozzle body171and is arranged concentrically with the nozzle body171with a predetermined gap therebetween. That is, the nozzle body171and the sleeve182keep a predetermined gap therebetween by interposing a plurality of spacers191with a predetermined gap therebetween in the circumferential direction. The gap between the nozzle body171and the sleeve182becomes a film air passage (film-air flow channel)192through which film air circulates.

The film air passage192is formed on the outer periphery of the nozzle body171and is formed from the base end side to the apical end side thereof. A base end side of the film air passage192communicates with the air passage (external flow channel)56and a part of the compressed air that flows into the air passage56from the compressor11via the supply passage57circulates as film air. The film air passage192injects the film air toward the front of the nozzle body171along the outer periphery of the nozzle body171.

Contraction portions172a,173a, and174aare respectively formed in the second fuel gas passage172, the first fuel gas passage173, and the cooling passage174, of the plurality of internal flow channels of the nozzle body171described above, by narrowing down the respective passages so that a passage area thereof decreases.

The contraction portion172aof the second fuel gas passage172has a circular cross section, and a plurality of contraction portions172aare formed to be arranged along the circumferential direction of the nozzle body171with a predetermined gap therebetween (at a regular interval). The contraction portion173aof the first fuel gas passage173and the contraction portion174aof the cooling passage174have a circular cross section similarly to the contraction portion172aof the second fuel gas passage172, and are formed in a plurality of numbers to be arranged along the circumferential direction of the nozzle body171with a predetermined gap therebetween (at a regular interval). The contraction portion173aof the first fuel gas passage173and the contraction portion174aof the cooling passage174are formed on the inner peripheral side of the contraction portions172aof the second fuel gas passage172and are arranged alternately along the circumferential direction.

In this manner, the plurality of contraction portions172a,173a, and174aare provided such that the plurality of contraction portions172aof the second fuel gas passage172, which are one part of the contraction portions172a,173a, and174a, are arrayed in the circumferential direction, and the contraction portions173aof the first fuel gas passage173and the contraction portions174aof the cooling passage174which are the other part of the contraction portions172a,173a, and174a, are arrayed in the circumferential direction. The plurality of contraction portions172aas one part thereof and the plurality of contraction portions173aand174aas the other part thereof are provided concentrically.

In the second fuel gas passage172, the first fuel gas passage173, and the cooling passage174of the plurality of internal flow channels of the nozzle body171described above, manifolds172b,173b, and174bare respectively formed between each passage and each injection hole. The manifold172bof the second fuel gas passage172is formed on an apical end side of the contraction portion172a. That is, the manifold172bof the second fuel gas passage172is formed on a downstream side of the contraction portion172ain a flow direction of the fuel gas F2that circulates in the second fuel gas passage172.

The manifold172bof the second fuel gas passage172is formed over the whole circumference of the nozzle body171in an annular shape. The manifold172bcommunicates with the plurality of contraction portions172aon an upstream side (the base end side) and with the plurality of second fuel-gas injection holes189on the downstream side (the apical end side).

The manifold174bof the cooling passage174is formed on the downstream side of the contraction portion174ain the flow direction of the cooling air A that circulates in the cooling passage174. The manifold174bof the cooling passage174is formed over the whole circumference of the nozzle body171in an annular shape, similarly to the manifold172b. The manifold174bis formed on the inner side than the manifold172band on the apical end side than the manifold172b. The manifold174bcommunicates with the plurality of contraction portions174aon the upstream side (the base end side) and with the plurality of air injection holes187on the downstream side (the apical end side).

The manifold173bof the first fuel gas passage173is formed on the downstream side of the contraction portion173ain a flow direction of the fuel gas F1that circulates in the first fuel gas passage173. The manifold173bof the first fuel gas passage173is formed over the whole circumference of the nozzle body171in an annular shape, similarly to the manifold172band the manifold174b. The manifold173bis formed on the apical end side than the manifold174b. The manifold173bcommunicates with the plurality of contraction portions173aon the upstream side (the base end side) and with the plurality of first fuel-gas injection holes188on the downstream side (the apical end side).

In this manner, the plurality of manifolds172b,173b, and174bare formed sequentially from the base end side to the apical end side of the nozzle body171in order of the manifolds172bof the second fuel gas passage172, the manifolds174bof the cooling passage174, and the manifolds173bof the first fuel gas passage173. Therefore, the manifolds172b,173b, and174bare formed so that the positions thereof are different from each other in the direction connecting the base end side and the apical end side of the nozzle body171.

Fluids such as the fuel gas F1, the fuel gas F2, the fuel oil F3, the cooling air A, and the water W that circulate in the respective passages172,173,174,175, and176in the pilot nozzle121according to the third embodiment are described next.

The fuel oil F3that flows into the fuel oil passage175from the fuel port64circulates in the fuel oil passage175and is injected from the fuel-oil injection portion185formed at the center of the nozzle body171toward the front of the nozzle body171.

The water W that flows into the water passage176from the water supply source circulates in the water passage176and is injected from the plurality of water injection holes186formed around the fuel-oil injection portion185of the nozzle body171toward the front of the nozzle body171and to the inner side of the nozzle body171.

The cooling air A that flows into the cooling passage174from the cooling-air supply port66circulates in the cooling passage174. At this time, the cooling air A passes through the contraction portion174aof the cooling passage174, thereby stabilizing a circulation amount of the cooling air A flowing toward the apical end side. Thereafter, the cooling air A passes through the manifold174bto circulate over the whole circumference of the nozzle body171. The cooling air A that has passed through the manifold174bis injected from the air injection holes187formed around the water injection holes186in the nozzle body171toward the front of the nozzle body171and to the inner side of the nozzle body171.

The fuel gas F1that flows into the first fuel gas passage173from the fuel port64circulates in the first fuel gas passage173. At this time, the fuel gas F1passes through the contraction portion173aof the first fuel gas passage173, thereby stabilizing a circulation amount of the fuel gas F1flowing toward the apical end side. Thereafter, the fuel gas F1passes through the manifold173bto circulate over the whole circumference of the nozzle body171. The fuel gas F1that has passed through the manifold173bis injected from the first fuel-gas injection holes188formed around the air injection holes187in the nozzle body171toward the front of the nozzle body171and to the outer side of the nozzle body171.

The fuel gas F2that flows into the second fuel gas passage172from the fuel port64circulates in the second fuel gas passage172. At this time, the fuel gas F2passes through the contraction portion172aof the second fuel gas passage172, thereby stabilizing a circulation amount of the fuel gas F2flowing toward the apical end side. Thereafter, the fuel gas F2passes through the manifold172bto circulate over the whole circumference of the nozzle body171. The fuel gas F2that has passed through the manifold172bis injected from the second fuel-gas injection holes189in the swirler vanes160provided around the nozzle body171toward the front of the nozzle body171.

The film air that flows into the film air passage192from the air passage56circulates in the film air passage192and is injected toward the front of the nozzle body171along the outer periphery of the nozzle body171.

As described above, according to the third embodiment, the fuel gas F1, the fuel gas F2, the fuel oil F3, the cooling air A, and the water W that are fluids can be circulated without being mixed, according to the second fuel gas passage172, the first fuel gas passage173, the cooling passage174, the fuel oil passage175, and the water passage176that are the plurality of internal flow channels in the nozzle body171. Further, because the fuel gas F1, the fuel gas F2, and the cooling air A that circulate in the second fuel gas passage172, the first fuel gas passage173, and the cooling passage174respectively pass through the contraction portions172a,173a, and174a, the circulation amount thereof toward the apical end side can be stabilized. Accordingly, the injection amount injected from the second fuel-gas injection holes189, the first fuel-gas injection holes188, and the air injection holes187can be stabilized.

According to the third embodiment, the fuel gas F1, the fuel gas F2, and the cooling air A having passed through the contraction portions172a,173a, and174apass through the manifolds172b,173b, and174b, respectively, and are injected from the second fuel-gas injection holes189, the first fuel-gas injection holes188, and the air injection holes187. Therefore, the fuel gas F1, the fuel gas F2, and the cooling air A injected from the second fuel-gas injection holes189, the first fuel-gas injection holes188, and the air injection holes187via the manifolds172b,173b, and174bcan be injected in the circumferential direction with a uniform pressure.

According to the third embodiment, in the direction connecting the base end side and the apical end side of the nozzle body171, the manifolds172b,173b, and174bcan be formed with a positional deviation from each other. Therefore, the manifolds172b,173b, and174bare formed not to be overlapped on each other in the radial direction of the nozzle body171, and the nozzle body171can have a compact configuration.

According to the third embodiment, because the respective injection holes (injection portions)185,186,187,188, and189can be formed so that the injection directions of fluids such as the fuel gas F1, the fuel gas F2, the fuel oil F3, the cooling air A, and the water W are made different from each other, the injection shape of the fluids can be an arbitrary shape.

According to the third embodiment, because the plurality of contraction portions172a,173a, and174acan be arranged circumferentially and concentrically, the contraction portions172a,173a, and174acan be arranged without intersecting with each other.

According to the third embodiment, because the fluids such as the fuel gas F1, the fuel gas F2, the fuel oil F3, the cooling air A, and the water W can be injected, the fuel oil F3can be combusted to generate combustion gas, the fuel gases F1and F2can be combusted to generate combustion gas, and the nozzle body71can be cooled by the water W and the cooling air A. Therefore, a pilot nozzle having high versatility can be acquired.

According to the third embodiment, the pilot nozzle121can inject the fuel gas F1, the fuel gas F2, the fuel oil F3, the cooling air A, and the water W that circulate in the respective passages172,173,174,175, and176with a uniform pressure without mixing the fluids with each other, from the respective injection holes (injection portions)185,186,187,188, and189in a state where the injection amount is stabilized. Therefore, combustion of the pilot nozzle121can be performed stably. Consequently, combustion by the gas turbine combustor12can be performed stably, thereby enabling to improve the turbine efficiency by the stable combustion.

According to the third embodiment, the second fuel gas passage172, the first fuel gas passage173, the cooling passage174, the fuel oil passage175, and the water passage176are formed as the plurality of internal flow channels. However, the configuration is not limited thereto, and a passage through which another fluid passes can be formed or a part of the passages can be omitted.

Fourth Embodiment

A gas turbine combustor130according to a fourth embodiment is described with reference toFIG. 8.FIG. 8is a sectional view illustrating an apical end of a pilot nozzle according to the fourth embodiment. In the fourth embodiment also, to avoid redundant explanations, portions different from those of the first to third embodiments are described, and portions having identical configurations as those of the first to third embodiments are denoted and described by like reference signs. In the pilot nozzle121according to the third embodiment, the water passage176is formed in a cylindrical shape along the outer periphery of the fuel oil passage175. However, in a pilot nozzle131according to the fourth embodiment, the water passage176is formed on an outer peripheral side of the fuel oil passage175.

As illustrated inFIG. 8, in the pilot nozzle131of the fourth embodiment, the nozzle body171has a hollow cylindrical shape, and the swirler vanes160are provided around the nozzle body171similarly to the third embodiment. In the nozzle body171, the fuel oil passage175, the first fuel gas passage173and the water passage176, and the second fuel gas passage172and the cooling passage174are sequentially formed from the inside (the center side) toward the outside. The fuel oil passage175is substantially identical to that of the first embodiment, and thus descriptions thereof are omitted.

The first fuel gas passage173is formed on the outer peripheral side of the fuel oil passage175in the nozzle body171, and the water passage176is also formed on the outer peripheral side of the fuel oil passage175inside the nozzle body171. The first fuel gas passage173and the water passage176are provided in a parallel array along the circumferential direction of the nozzle body171.

The second fuel gas passage172is formed on the outer peripheral side of the first fuel gas passage173and the water passage176inside the nozzle body171, and the cooling passage174is also formed on the outer peripheral side of the first fuel gas passage173and the water passage176inside the nozzle body171. The second fuel gas passage172and the cooling passage174are provided in a parallel array along the circumferential direction of the nozzle body171.

As in the third embodiment, in the pilot nozzle131illustrated inFIG. 8, the contraction portions172a,173a, and174aand the manifolds172b,173b, and174bare respectively formed in the second fuel gas passage172, the first fuel gas passage173, and the cooling passage174. The contraction portions172a,173a, and174aand the manifolds172b,173b, and174bare identical to those of the third embodiment, and thus descriptions thereof are omitted. Further, as illustrated inFIG. 8, in the pilot nozzle131according to the fourth embodiment, a manifold176bis formed in the water passage176. The manifold176bof the water passage176is formed on the apical end side of the nozzle body171than other manifolds172b,173b, and174b. The manifold176bof the water passage176is formed over the entire periphery of the nozzle body171in an annular shape. The manifold176bis formed inward of the manifold174b, as illustrated inFIG. 8, and is formed on the apical end side than the manifold174b. The manifold176bcommunicates with the plurality of water injection holes186on the downstream side (the apical end side) thereof.

As described above, according to the fourth embodiment, the plurality of internal flow channels can be arranged in a pattern different from those of the first embodiment.

Fifth Embodiment

A gas turbine combustor140according to a fifth embodiment is described next with reference toFIG. 9.FIG. 9is a sectional view illustrating an apical end of a pilot nozzle according to the fifth embodiment. In the fifth embodiment also, to avoid redundant explanations, portions different from those of the first to fourth embodiments are described, and portions having identical configurations as those of the first to fourth embodiments are denoted and described by like reference signs. In the pilot nozzles121and131according to the third and fourth embodiments, the film air passage192is formed so as to communicate with the air passage56, which is the external flow channel outside of the nozzle body171. However, in a pilot nozzle141according to the fifth embodiment, the film air passage192is an internal flow channel of a nozzle body142. In other words, the film air passage192, which is an external flow channel in the pilot nozzles121and131according to the third and fourth embodiments, is an internal flow channel in the fifth embodiment.

Specifically, as illustrated inFIG. 9, the nozzle body142of the pilot nozzle131is provided with a plurality of internal flow channels formed therein. The first fuel gas passage173, the second fuel gas passage172, a cooling passage (cooling flow channel)174A, a film air passage (film-air flow channel)174B, the fuel oil passage175, and the water passage176are formed as the internal flow channels. In the fifth embodiment, because the first fuel gas passage173, the second fuel gas passage172, the fuel oil passage175, and the water passage176are identical to those of the third embodiment, descriptions thereof are omitted. The fifth embodiment has a configuration in which the sleeve182according to the third embodiment is omitted (in other words, the sleeve is integrated with the nozzle body142) therefrom.

The cooling passage174A and the film air passage174B are passages respectively branched from the manifold174bin the cooling passage174according to the third embodiment. That is, the cooling passage174A is a flow channel in which the cooling air passes through the contraction portion174aand the manifold174bin the cooling passage174according to the third embodiment toward the air injection holes187. Meanwhile, the film air passage174B is a flow channel in which the cooling air, as film air, passes through the contraction portion174aand the manifold174bin the cooling passage174according to the third embodiment toward the film air passage192according to the third embodiment. That is, the film air passage192according to the third embodiment forms a part (an apical end) of the film air passage174B according to the fifth embodiment.

In the cooling passage174A, a cooling air manifold174Ab is provided between the manifold174band the air injection holes187. The cooling air manifold174Ab is formed over the entire periphery of the nozzle body142in an annular shape. The cooling air manifold l74Ab is formed inside of the film air passage192and outside of the manifold173bon the apical end side, and formed on the apical end side than a film air manifold174Bb described later. The cooling air manifold174Ab communicates with the manifold174bon the upstream side (base end side) thereof and communicates with the air injection holes187on the downstream side (apical end side) thereof.

In the film air passage174B, the film air manifold174Bb is provided between the manifold174band the film air passage192on the apical end side. The film air manifold174Bb is formed over the entire periphery of the nozzle body142in an annular shape. The film air manifold174Bb is formed on the outermost side and on the base end side than the cooling air manifold174Ab. The film air manifold174Bb communicates with the manifold174bon the upstream side (base end side) thereof and communicates with the film air passage192on the apical end side on the downstream side (apical end side) thereof.

The cooling passage174A and the film air passage174B formed in this manner are arranged on the same circumference as the first fuel gas passage173. The cooling passage174A and the film air passage174B are formed in a circular hole shape in cross section, and the first fuel gas passage173is formed in an elongated hole shape having an oval shape (for example, an elongated shape) in cross section. The cooling passage174A and the film air passage174B on the apical end side of the manifold174bare formed in a plurality of numbers in the circumferential direction, and the first fuel gas passage173on the base end side of the manifold173bis formed in a plurality of numbers in the circumferential direction. The plurality of cooling passages174A and film air passages174B, and the plurality of first fuel gas passages173are arranged alternately along the circumferential direction. The cooling passages174A and the film air passages1743are arranged alternately along the circumferential direction.

Accordingly, the cooling air A that flows into the cooling passage174from the cooling-air supply port66passes through the contraction portion174a, thereby stabilizing the circulation amount of the cooling air A flowing toward the apical end side. Thereafter, the cooling air A passes through the manifold174b, thereby circulating around the whole circumference of the nozzle body142. A part of the cooling air A having passed through the manifold174bflows into the cooling passages174A, and a part of the remaining cooling air A flows into the film air passages174B. The cooling air A that flows into the cooling passages174A passes through the cooling air manifolds174Ab, thereby circulating around the whole circumference of the nozzle body142. The cooling air A having passed through the cooling air manifolds174Ab is injected from the air injection holes187toward the front of the nozzle body142and to the inner side of the nozzle body142. Meanwhile, the cooling air A that flows into the film air passages174B passes through the film air manifolds174Bb, thereby circulating around the whole circumference of the nozzle body142. The cooling air A having passed through the film air manifolds174Bb is injected from the film air passage192on the apical end side toward the front of the nozzle body142.

As described above, according to the fifth embodiment, the plurality of internal flow channels can be arranged in an arrangement pattern different from those of the first to fourth embodiments. That is, the fuel oil passage175, the water passage176, the first fuel gas passage173, the second fuel gas passage172, the cooling passages174A, and the film air passages174B can be the internal flow channels of the nozzle body142.

The first to fifth embodiments have been described by applying the present invention to the pilot nozzles59,121,131, and141. However, the present invention is not particularly limited so long as the injection nozzle can inject cooling air toward the circulating flow, and can be applied to, for example, the main nozzle62according to the arrangement of the pilot nozzles59,121,131, and141and the main nozzle62.

REFERENCE SIGNS LIST