JP6037736B2 - Gas turbine combustor and gas turbine engine equipped with the same - Google Patents

Description

  The present invention relates to a gas turbine combustor capable of reducing emissions by promoting mixing of air and fuel supplied from a main burner and preventing backfire, and a gas turbine engine including the gas turbine combustor.

  In recent years, with increasing interest in environmental problems, reduction of emissions of nitrogen oxides (hereinafter referred to as NOx) has been demanded. The gas turbine engine is no exception, and various researches and developments on the combustor are in progress.

  For example, in a premixing type combustor widely applied to gas turbine engines, it is known that making the mixing ratio of fuel gas and air uniform is effective in reducing NOx. If the mixing ratio is not uniform, the flame in the region where the fuel gas concentration is high becomes locally hot, and there is a concern that a large amount of NOx is generated.

  The conventional gas turbine combustor disclosed in Patent Document 1 includes a pilot burner disposed along the central axis of the combustion cylinder and surrounds the pilot burner, as shown in FIGS. And a plurality of main burners arranged as described above, and an extension nozzle is connected to the main nozzle (premixing nozzle) of each main burner. Each of these extension nozzles has an independent substantially cylindrical shape, and an opening on each outlet side thereof is disposed so as to surround the periphery of the pilot cone connected to the pilot burner.

  Each main nozzle is provided with a swirler (swirl blade), which makes the fuel mixture flowing in the main nozzle a swirling flow to achieve a uniform fuel / air mixing ratio and generate NOx. Is suppressed.

  Since the vicinity of the inner wall surface of the extension nozzle has a low flow velocity, flashback (backfire) is likely to occur. In order to prevent this flashback, film-like air (film air) is introduced from the connection portion between the pilot burner and the extension nozzle. Specifically, a gap is provided in the connection portion between the main burner and the extension nozzle, and a part of the compressed air passing through the outer peripheral side of the main burner is taken from this gap and supplied to the inner surface of the extension nozzle as film air. The The film air dilutes the fuel mixture in the vicinity of the inner wall surface of the extension nozzle, and the occurrence of flashback is suppressed. The film air also has an effect of cooling the inner wall surface of the extension nozzle.

JP 2002-61841 A

  However, the conventional gas turbine combustor as described above has the following problems because the extension nozzles connected to the downstream side of the plurality of main burners have each formed an independent tubular shape.

  First, as described above, in order to prevent flashback inside each extension nozzle, film air is formed on the inner surface of the extension nozzle, but since each extension nozzle is independent, the total inner circumferential length thereof Increases and the amount of air required to form film air increases. For this reason, the air that should be flown to the main burner is subtracted to reduce the film air formation, and the fuel concentration (air-fuel ratio) of the fuel mixture generated by the main burner tends to increase. . In this way, the fuel mixture with a high fuel concentration cannot be mixed uniformly because the extension nozzle is short, and a region with a high fuel concentration remains in the center of the flow of the fuel mixture injected from the extension nozzle. End up.

  In addition, as described above, swirlers (swirl blades) are installed inside each main burner, so that the fuel / air mixture flowing in the main nozzle is swirled to achieve a uniform fuel / air mixture ratio. However, inside the extension nozzle, the fuel concentration distribution tends to be stratified in the radial direction by centrifugal force, and the mixing rate tends to decrease.

  Further, in order to prevent high-temperature combustion gas from being caught in the low flow velocity region around the extension nozzle, air is discharged from the base holding the main burner and the pilot burner. As a result, the amount of air to be flowed to the main burner further decreased, and the air-fuel ratio of the fuel mixture generated by the main burner tended to be further increased.

Due to the above problems, it is difficult to suppress the generation of NOx.
The present invention has been made in view of the above circumstances, and is a gas turbine combustion capable of promoting the mixing of air and fuel supplied from a main burner to reduce emissions such as NOx and preventing backfire. And a gas turbine engine including the same.

In order to solve the above problems, the present invention employs the following means.
That is, a gas turbine combustor according to the present invention includes a pilot burner disposed along a central axis of a combustion cylinder, a plurality of main burners disposed so as to surround the pilot burner, and the plurality of main burners. Each of the plurality of cylindrical premixing nozzles forming a primary mixing region therein, and an annular continuous in the circumferential direction of the pitch circle of the premixing nozzle, Each of the mixing nozzles is connected to an outlet side thereof, and a secondary mixing region is formed therein, and an annular extension nozzle having a jet outlet opened downstream is provided, and the premixing nozzle and the annular nozzle are provided. A constriction part for constricting the flow of the fuel mixture flowing from the premixing nozzle to the annular extension nozzle is provided at a connection part with the extension nozzle, and the annular extension is provided. The slip has an annular outer peripheral wall surface and an annular inner peripheral wall surface along the circumferential direction of the pitch circle, and the contraction portion has the outer peripheral wall surface directed radially inward of the pitch circle, A radial dimension between the outer peripheral wall surface and the inner peripheral wall surface is narrowed toward the radially outer side of the pitch circle of the wall surface .

  According to this gas turbine combustor, the premixing nozzle provided in each of the plurality of main burners is an annular extension nozzle that forms an annular shape that is annularly continuous along the circumferential direction of the pitch circle of these premixing nozzles. Since they are connected to each other, the fuel mixture premixed in the primary mixing area inside each premixing nozzle flows into the secondary mixing area inside the annular extension nozzle, where it further mixes with each other. .

  For this reason, it is possible to promote the mixing of the compressed air flowing from each main burner to the annular extension nozzle and the fuel to prevent stratification of the fuel concentration distribution, and to make the mixture ratio of the fuel mixture uniform. Since the fuel mixture that is uniformly mixed in this way is supplied to the combustion region, there is no portion where the fuel gas concentration is locally high, the combustion temperature is made uniform, and the generation of NOx can be reduced. .

  Moreover, since the wall surface of the annular extension nozzle is continuous in the circumferential direction, the circumferential length of the wall surface is much shorter than that of a conventional independent extension nozzle. For this reason, the amount of air required to form film air for flashback prevention on the inner surface of the annular extension nozzle and the air that must be supplied to the outer periphery of the annular extension nozzle to prevent the entrainment of combustion gas. The amount is very small.

  Accordingly, a large amount of air that should be flown to the main burner is not deducted and reduced, thereby preventing an increase in the fuel concentration (air-fuel ratio) of the fuel mixture generated by the main burner. However, it is possible to uniformly mix the fuel mixture and eliminate the high fuel concentration region, lower the combustion temperature to reduce NOx, and reduce the possibility of backfire.

  In the above configuration, the plurality of premixing nozzles may be provided with swirl flow generating means for causing swirl flow in the same rotation direction.

  According to the above configuration, the fuel mixture flowing in each premixing nozzle (primary mixing region) becomes a swirling flow by the action of the swirling flow generating means. Since a low flow velocity region is generated at the center of these swirling flows, there has been a possibility of backfire in this low flow velocity region. However, when the fuel mixture which is such a swirl flow merges inside the annular extension nozzle (secondary mixing region), the flow of the adjacent swirl flows is canceled and the circumferential direction of the annular extension nozzle A large counter rotating swirl flow swirling in the opposite direction on the outer peripheral side and the inner peripheral side is formed. For this reason, the low speed region is erased.

  Therefore, in the annular extension nozzle (secondary mixing region), the mixing of the fuel mixture flowing from each main burner is promoted, and the locally high fuel concentration portion or the low speed region is included in the flow of the combustion mixture. Will not occur. Therefore, the rise in combustion temperature can be prevented to suppress the generation of NOx, and backfire can be prevented.

  In the above-described configuration, it is preferable that a connecting portion between the premixing nozzle and the annular extension nozzle is provided with a contraction portion that contracts the flow of the fuel mixture flowing from the premixing nozzle to the annular extension nozzle. .

  According to the above configuration, when the fuel mixture flows from the premixing nozzle into the annular extension nozzle, the flow at the connection portion is contracted by the contraction portion, the flow velocity is accelerated, and the low flow velocity region is removed. Further, the boundary layer on the inner wall surface of the annular extension nozzle can be thinned. For these reasons, the fuel mixture can be mixed uniformly to reduce NOx and prevent backfire.

  In the above configuration, the air flowing around the main burner is introduced into the annular extension nozzle at least one of the connecting portion between the premixing nozzle and the annular extension nozzle, or the annular extension nozzle itself. Air introducing means for forming film air on the inner wall surface of the annular extension nozzle by the introduced air may be provided.

  According to the above configuration, the film air is formed on the inner wall surface of the annular extension nozzle, and the fuel concentration in the low flow velocity region near the wall surface is reduced, thereby reducing the fuel mixture flowing near the inner wall surface to a combustible limit concentration or less. You can prevent backfire.

  The said structure WHEREIN: You may further provide the film air swirling means which generates a swirling flow in the said film air in the said air introduction means.

  According to the above configuration, the film air can be swung in accordance with the swirling direction of the fuel mixture in the main burner, which is swirled to promote mixing, thereby weakening swirling in the annular extension nozzle. This prevents the occurrence of NOx and promotes the mixing of the fuel mixture more effectively, and prevents backfire.

  In the above-described configuration, the air introduction means may be configured such that the introduced film air flows over a predetermined length along the outer wall surface of at least one of the premixing nozzle or the annular extension nozzle and then the inner wall surface of the annular extension nozzle. It may be configured to be introduced into.

  According to the above configuration, the premixing nozzle and the annular extension nozzle can be convectively cooled from the outer peripheral side by the film air. As a result, even if a backfire occurs due to an abnormal situation, they are prevented from being burned out and continuous operation is possible.

  Further, a gas turbine engine according to the present invention includes a compressor that compresses air, any one of the gas turbine combustors that combusts the air compressed in the compressor, and combustion that is ejected from the gas turbine combustor. And a turbine driven by gas expansion.

  According to the above configuration, mixing of air and fuel generated in the main burner of the combustor is promoted to prevent stratification of the fuel concentration distribution, and the mixing ratio of the fuel mixture is made uniform, so that the combustion temperature is increased. It can be made uniform to reduce the generation of NOx and prevent backfire.

  As described above, according to the gas turbine combustor and the gas turbine engine including the gas turbine combustor according to the present invention, the mixing of air and fuel supplied from the main burner is promoted to reduce the emission of NOx and the like, and backfire Can be prevented.

It is a longitudinal cross-sectional view of the gas turbine combustor which shows 1st Embodiment of this invention. FIG. 2 is a front view of a main burner and an annular extension nozzle as viewed in the direction of arrow II in FIG. 1. It is a front view explaining the formation process of a counter rotating swirl | vortex flow. It is a longitudinal cross-sectional view which shows the state by which the fuel mixture is contracted. It is a schematic diagram which shows the velocity distribution of the fuel mixture which was contracted. It is a longitudinal cross-sectional view of the gas turbine combustor which shows 2nd Embodiment of this invention. It is a longitudinal cross-sectional view of the gas turbine combustor which shows 3rd Embodiment of this invention. It is a longitudinal cross-sectional view of the gas turbine combustor which shows 4th Embodiment of this invention. It is a longitudinal cross-sectional view of the gas turbine combustor which shows 1st reference embodiment of this invention. It is a longitudinal cross-sectional view of the gas turbine combustor which shows 2nd reference embodiment of this invention. It is a longitudinal cross-sectional view of the gas turbine combustor which shows 3rd reference embodiment of this invention.

  Hereinafter, a plurality of embodiments of a gas turbine combustor according to the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a longitudinal sectional view of a gas turbine combustor showing a first embodiment of the present invention.
The gas turbine combustor 1 is mounted on a gas turbine engine (not shown). As is well known, a gas turbine engine is driven by a compressor that compresses air, a gas turbine combustor that combusts air compressed in the compressor, and expansion of combustion gas ejected from the gas turbine combustor. The turbine is rotated at high speed using the energy of the combustion gas generated in the gas turbine combustor, and the generator is driven by obtaining shaft output. And the gas turbine combustor 1 which concerns on this invention is used as said gas turbine combustor.

  The gas turbine combustor 1 includes a combustion cylinder 2 forming an outer peripheral portion thereof, a single pilot burner 3 disposed along a central axis C of the combustion cylinder 2, and so as to surround the periphery of the pilot burner 3. It has the structure of the general premixing system provided with a plurality of (for example, 8) main burners 4 arranged at intervals. The compressed air A compressed by a compressor (not shown) flows from the left side to the right side in FIG. 1 in the gas turbine combustor 1 (combustion cylinder 2).

  The pilot burner 3 includes a shaft-like pilot nozzle 5 at the axial center. A plurality of fuel injection holes 6 are drilled at the downstream end of the pilot nozzle 5, from which fuel F1 is injected. Also, a substantially funnel-shaped pilot nozzle outer cylinder 7 is attached so as to surround the pilot nozzle 5 with a space therebetween. The diameter of the pilot nozzle outer cylinder 7 is gradually reduced toward the downstream side of the flow of the compressed air A.

  A plurality of wing-like pilot swirlers 8 are installed on the inner peripheral surface of the pilot nozzle outer cylinder 7 so as to stand up toward the pilot nozzle 5. Since these pilot swirlers 8 are given a pitch angle that is inclined in the same direction, the flow of the compressed air A becomes a swirl flow (swirl flow), and is injected from the compressed air A and the fuel injection holes 6. Mixing with the fuel F1 is promoted. Thus, in the pilot burner 3, the fuel F1 is mixed with the compressed air A in advance to generate the fuel mixture M1.

  Further, a pilot cone 9 is provided so as to cover the periphery of the pilot nozzle 5. The pilot cone 9 is formed in a substantially funnel shape whose diameter increases toward the downstream side of the flow. Inside the upstream end portion of the pilot cone 9, the downstream end portion of the pilot nozzle outer cylinder 7 is Shortly inserted with a gap in the radial direction. The pilot cone 9 prevents the fuel mixture M1 injected from the pilot burner 3 and its combustion flame from diffusing in the centrifugal direction, and prevents interference with the fuel mixture M2 from the main burner 4 described later. The

  On the other hand, the plurality of main burners 4 are provided with shaft-shaped main nozzles 11 in the respective shaft centers. The main nozzle 11 has a tip that narrows toward the downstream side of the flow of compressed air. A premixing nozzle 12 is provided near each outlet of the main burner 4. The premixing nozzle 12 has a cylindrical shape, and its upstream inlet portion is expanded in a bell mouth shape, and the inside is a primary mixing region 13.

  The plurality of wing-like support stays 14 extending in the radial direction from the main nozzle 11 support the premixing nozzle 12 from the inside, so that the premixing nozzle 12 is installed concentrically so as to surround the main nozzle 11. The support stay 14 is provided with a plurality of fuel injection holes 15 from which fuel F2 is injected. Thus, in the main burner 4, the fuel F2 is mixed with the compressed air A in advance to generate the fuel mixture M2.

  Also, a plurality of wing-shaped main swirlers 16 (swirl flow generating means) stand up toward the main nozzle 11 at a position downstream of the fuel injection hole 15 on the inner peripheral surface of the premixing nozzle 12. is set up. Since these main swirlers 16 are provided with pitch angles that are inclined in the same direction, as shown in FIG. 3, the flow of the fuel mixture M2 passing through the inside of each premixing nozzle 12 has the same rotational direction. A swirling flow (swirl flow) S is generated, which promotes mixing of the fuel mixture M2.

  An annular extension nozzle 18 is connected to the downstream side of each main burner 4 (premixing nozzle 12). As shown in FIGS. 1 and 2, the annular extension nozzle 18 has an annular shape (annular shape) that continues along the circumferential direction of the pitch circle P of the premixing nozzle 12. The peripheral wall surface 18b is continuous in the circumferential direction (see FIG. 2). For this reason, as shown in FIG. 1, the annular extension nozzle 18 surrounds the pilot cone 9 of the pilot burner 3. In the present embodiment, the radius of the pitch circle P of the premixing nozzle 12 and the radius of the pitch circle C1 of the passage of the annular extension nozzle 18 are the same radius R1. The diameter of the pilot cone 9 is indicated by D1.

  The outlet side of each premixing nozzle 12 is connected to the inlet side (upstream side) of the annular extension nozzle 18, and is a portion excluding the connecting portion of the premixing nozzle 12, that is, between the premixing nozzles 12. The portion is the end plate portion 19 (see the hatched portion in FIG. 2). For this reason, the upstream side of the annular extension nozzle 18 does not communicate with the outside.

  The downstream side of the annular extension nozzle 18 is open and serves as a spout 20. The jet nozzle 20 has an annular shape, and the premix nozzles 12 of the plurality of main burners 4 can be seen from the jet nozzle 20 as shown in FIG. The inside of the annular extension nozzle 18 is a secondary mixing region 21.

  A constricted portion 22 is provided at the connecting portion between the annular extension nozzle 18 and the premixing nozzle 12. The contracted portion 22 is integrally formed on the annular extension nozzle 18 side, and the longitudinal cross-sectional shape (see FIG. 1) of the contracted portion 22 is a bell mouth shape (funnel shape). By providing the contracted flow part 22, the thickness (diameter dimension) of the annular annular extension nozzle 18 is narrowed toward the downstream side. For this reason, in FIG. 2, the inner peripheral side and the outer peripheral side of the plurality of premixing nozzles 12 that can be seen from the ejection port 20 are hidden by the contracted portion 22.

  The combustion process in the gas turbine combustor 1 configured as described above will be described. First, compressed air A compressed in a compressor of a gas turbine engine (not shown) flows into the combustion cylinder 2, and the pilot burner 3 and It flows from the upstream end side of the main burner 4 toward the downstream end side.

  In the pilot burner 3, when the compressed air A flows along the pilot nozzle outer cylinder 7, the fuel F1 injected from the fuel injection hole 6 is mixed while being swirled by the pilot swirler 8, and becomes the fuel mixture M1. Then, the fuel is ejected from the pilot cone 9 toward a combustion region (not shown). The fuel mixture M1 is ignited by a seed flame (not shown), and diffusion combustion is performed inside and downstream of the pilot cone 9.

  On the other hand, in the main burner 4, when the compressed air A flows along the premixing nozzle 12, the fuel F2 injected from the fuel injection holes 15 while being swirled by the main swirler 16 is mixed and the fuel mixture M2 Then, the fuel is ejected from the ejection port 20 of the annular extension nozzle 18 toward a combustion region (not shown). This fuel mixture M2 is ignited and burned by touching the combustion gas (flame) of the fuel mixture M1 ejected from the pilot cone 9 and combusted.

  A turbine (not shown) of the gas turbine engine is driven by the expansion pressure of the combustion gas of the fuel mixture M1 and M2 that burns in this way and is taken out as an output, and a compressor provided coaxially with the main shaft of the turbine. Driven and compressed air A is supplied.

  In the gas turbine combustor 1, the premixing nozzles 12 provided in each of the plurality of main burners 4 are annular extension nozzles 18 that form an annular shape that is annularly continuous along the circumferential direction of the pitch circle P. The fuel mixture M2 previously mixed in the primary mixing region 13 inside each premixing nozzle 12 flows into the secondary mixing region 21 inside the annular extension nozzle 18, Here, they are further mixed with each other.

  For this reason, the mixing of the compressed air A and the fuel F2 flowing from each main burner 4 to the annular extension nozzle 18 is promoted to prevent stratification of the fuel concentration distribution, and the mixing ratio of the fuel mixture M2 is made uniform. Can do. Since the fuel mixture M2 thus uniformly mixed is supplied to the combustion region, there is no portion where the fuel gas concentration is locally high, the combustion temperature is made uniform, and the generation of NOx can be reduced. it can.

  In addition, since the outer peripheral wall surface 18a and the inner peripheral wall surface 18b of the annular extension nozzle 18 are continuous in the circumferential direction, the peripheral lengths of these inner and outer peripheral wall surfaces 18a and 18b are much higher than those of conventional independent extension nozzles. It has become shorter. For this reason, the amount of air required to form film air for preventing flashback on the inner and outer peripheral wall surfaces 18a and 18b of the annular extension nozzle 18 and the outer periphery of the annular extension nozzle 18 to prevent the entrainment of combustion gas. The amount of air that must be supplied is very small.

  Accordingly, a large amount of air that should be flown to the main burner 4 is not subtracted and reduced, and the fuel concentration (air-fuel ratio) of the fuel mixture M2 generated by the main burner 4 is thereby increased. In addition, the fuel mixture M2 is uniformly mixed to eliminate the region where the fuel concentration is high, the combustion temperature is lowered to reduce NOx, and the possibility of backfire can be reduced.

  Moreover, since the main swirler 16 as the swirl flow generating means is installed in the premixing nozzle 12 of each main burner 4, the flow of the fuel mixture M2 passing through the inside of each premixing nozzle 12 as shown in FIG. A swirling flow (swirl flow) S in the same rotational direction is generated. Since a low flow velocity region is generated in the central portion of these swirl flows S, there has been a possibility of backfire in this low flow velocity region.

  However, when such a swirl flow S of the fuel mixture M2 merges inside the annular extension nozzle 18 (secondary mixing region 21), the swirl flows adjacent to each other, that is, in FIG. The flow indicated by the arrow Sa cancels each other and only the flow indicated by the arrow Sb remains. These arrows Sb are combined to form large counter rotating swirl flows S1 and S2 swirling in opposite directions along the circumferential direction of the annular extension nozzle 18 on the outer peripheral side and the inner peripheral side. For this reason, the low speed region generated in the premixing nozzle 12 is erased in the annular extension nozzle 18.

  Therefore, in the secondary mixing region 21 inside the annular extension nozzle 18, the mixing of the fuel mixture M2 flowing from each main burner 4 is promoted by the flow of the counter-rotating swirl flows S1 and S2, and the fuel mixture M2 There are no local high fuel concentration or low speed regions in the flow. For this reason, it is possible to prevent the rise of the combustion temperature, suppress the generation of NOx, and prevent backfire.

  Further, since the flow reducing portion 22 is provided at the connecting portion between the premixing nozzle 12 of each main burner 4 and the annular extension nozzle 18, the premixing nozzle 12 changes to the annular extension nozzle 18 as shown in FIG. 4. The flow of the flowing fuel mixture M2 is contracted by the contraction section 22. For this reason, the flow velocity of the fuel mixture M2 after the contracted flow portion 22 is accelerated, and the low flow velocity region is removed.

  That is, as shown in FIG. 5, the velocity distribution V1 of the fuel mixture M2 inside the premixing nozzle 12 is fast at the center of the premixing nozzle 12, becomes slow as it approaches the inner peripheral wall, and at a position close to the inner peripheral wall. Although a low flow velocity region is formed, when this flow is reduced by the reduced flow portion 22 and enters the annular extension nozzle 18, a substantially uniform velocity distribution V2 is obtained, and the low flow velocity region is eliminated. Further, the boundary layer on the inner wall surface of the annular extension nozzle 18 can be thinned.

  For these reasons, the fuel mixture M2 can be mixed more uniformly inside the annular extension nozzle 18, NOx can be reduced more effectively, and backfire can be prevented.

[Second Embodiment]
FIG. 6 is a longitudinal sectional view of a gas turbine combustor showing a second embodiment of the present invention.
Here, only the main burner 4 and the annular extension nozzle 18 are shown. The configuration of the main burner 4 (premixing nozzle 12) is the same as that in the first embodiment.

  The annular extension nozzle 18 has a two-piece structure including a nozzle body 18c and a nozzle extension pipe 18d, and the nozzle extension pipe 18d is spaced from the outer periphery of the nozzle body 18c at the connecting portion of both the members 18c and 18d. And an annular gap 25 (air introduction means) is formed between the members 18c and 18d. The inlet portions on the upstream side of both members 18c and 18d are both expanded in a bell mouth shape.

  Similarly, at the connecting portion between the premixing nozzle 12 and the annular extension nozzle 18 (nozzle body 18c), the nozzle body 18c surrounds the outer periphery of the premixing nozzle 12 with an interval therebetween, and both the members 12, 18c. An annular gap 26 (air introduction means) is formed between them.

  Since these annular gaps 25 and 26 are provided, a part of the compressed air A flowing around the main burner 4 enters the annular extension nozzle 18 from the annular gaps 25 and 26 whose inlets are formed in a bell mouth shape. After being introduced, film air FA is formed on the inner wall surface of the annular extension nozzle 18. For this reason, the fuel concentration in the low flow velocity region in the vicinity of the inner wall surface of the annular extension nozzle 18 (18c, 18d) becomes thin, and thereby the combustible limit concentration of the portion of the fuel mixture M2 flowing in the vicinity of the inner wall surface of the annular extension nozzle 18 is reduced. The following can be used to prevent combustion and flashback.

[Third Embodiment]
FIG. 7 is a longitudinal sectional view of a gas turbine combustor showing a third embodiment of the present invention.
Here, in addition to the configuration of the second embodiment shown in FIG. 6, swirl wing-like film air swirlers 29 and 30 (film air swirling means) are respectively installed in the annular gaps 25 and 26 that are air introducing means. ing. Other parts are the same as those of the second embodiment. The film air swirlers 29 and 30 generate a swirl flow in the film air FA (see FIG. 6) formed on the inner wall surface of the annular extension nozzle 18 by the annular gaps 25 and 26.

  The plurality of swirl blades forming the film air swirlers 29 and 30 are given pitch angles that are inclined in the same direction. The inclination direction of the pitch angle is preferably the same as the inclination direction of the main swirler 16 installed in the premixing nozzle 12. Thereby, the film air FA can be swirled in accordance with the swirling direction of the fuel mixture M2 (see FIG. 6) that is swirled to promote mixing inside the premixing nozzle 12. For this reason, the swirling flow (double counter-rotating swirling flow S1, S2) in the annular extension nozzle 18 is prevented from weakening, more effectively promoting the mixing of the fuel mixture, reducing the generation of NOx, Backfire can be prevented.

[Fourth Embodiment]
FIG. 8 is a longitudinal sectional view of a gas turbine combustor showing a fourth embodiment of the present invention.
Here, compared with the structure of 3rd Embodiment shown in FIG. 7, the length of the annular clearances 25 and 26 which are air introduction means is extended. Specifically, the premixing nozzle 12 is covered by the nozzle body 18c of the annular extension nozzle 18 in a range of about 50% or more of the total length from the downstream end thereof. Further, the nozzle main body 18c is covered with a nozzle extension pipe 18d in a range of about 50% or more of the length from the downstream end to the downstream end of the premixing nozzle 12.

  Since the lengths of the annular gaps 25 and 26 are thus extended, the film air (not shown) introduced from the annular gaps 25 and 26 is supplied to the premixing nozzle 12 and the annular extension nozzle 18 (nozzle body 18c). After flowing for a predetermined length along the outer wall surface of the nozzle, it is introduced into the inner wall surface of the annular extension nozzle 18.

  According to this configuration, the premixing nozzle 12 and the annular extension nozzle 18 can be convectively cooled from the outer peripheral side by the film air. Thereby, even if a backfire occurs due to an abnormal situation, the premix nozzle 12 and the annular extension nozzle 18 can be prevented from being burned out, and continuous operation is possible.

[First embodiment]
FIG. 9 is a longitudinal sectional view of a gas turbine combustor showing a first reference embodiment of the present invention.
This gas turbine combustor 31 is different from the gas turbine combustor 1 of the first embodiment shown in FIG. 1 in that the pitch circle P of the premixing nozzle 12 and the pitch circle C2 of the passage of the annular extension nozzle 18 have the same radius. Absent. That is, the radius R2 of the pitch circle C2 of the annular extension nozzle 18 is larger than the radius R1 of the pitch circle P of the premixing nozzle 12. Accordingly, the diameter D2 of the pilot cone 9 of the pilot burner 3 is larger than the diameter D1 of the pilot cone 9 in the first embodiment. Since the configuration of other parts is the same as that of the first embodiment, the same reference numerals are given to the respective parts and the description thereof is omitted.

  According to this configuration, the opening area of the pilot cone 9 can be made larger than the opening area of the annular extension nozzle 18. Here, when the inner peripheral side of the annular extension nozzle 18 is throttled, the swirl flow on the inner peripheral side inside the main burner 4 (premixing nozzle 12) can be crushed and eliminated. Thereby, mixing with the gas ejected from the pilot burner 3 is suppressed, and a long flame can be achieved.

[Second embodiment]
FIG. 10 is a longitudinal sectional view of a gas turbine combustor showing a second reference embodiment of the present invention.
In this gas turbine combustor 41, contrary to the gas turbine combustor 31 of the first reference embodiment, the radius R 3 of the pitch circle C 3 of the annular extension nozzle 18 is larger than the radius R 1 of the pitch circle P of the premixing nozzle 12. Is smaller. Accordingly, the diameter D3 of the pilot cone 9 of the pilot burner 3 is reduced accordingly.

  According to this configuration, the opening area of the pilot cone 9 can be made smaller than the opening area of the annular extension nozzle 18. Here, since the inner peripheral side of the annular extension nozzle 18 is not restricted, the swirling flow on the inner peripheral side inside the main burner 4 (premixing nozzle 12) can be completely left. Thereby, mixing with the gas ejected from the pilot burner 3 can be promoted, and the flame can be shortened.

[Third Reference Embodiment]
FIG. 11 is a longitudinal sectional view of a gas turbine combustor showing a third reference embodiment of the present invention.
In this gas turbine combustor 51, the radius R4 of the pitch circle C4 of the passage of the annular extension nozzle 18 is larger than the radius R1 of the pitch circle P of the premixing nozzle 12 as in the case of the first reference embodiment. . The diameter D4 of the pilot cone 9 is the same as the diameter D2 in the first reference embodiment.

  The annular extension nozzle 18 extends from the inner peripheral side of the premixing nozzle 12 on the upstream side and expands radially outward toward the downstream side, and the radius R4 of the pitch circle C4 of the passage in the most downstream portion has a premixing nozzle. It is larger than the radius R1 of the 12 pitch circles P. That is, the diameter is increased while smoothly curving from the upstream side toward the downstream side.

  According to this configuration, the pilot cone 9 is smoothly expanded so that the flow of the fuel mixture flowing through the pilot burner 3 is made smooth, and the flame flow from the main burner 4 is changed into the downstream portion 2 a of the combustion cylinder 2. It is possible to extend along the peripheral wall surface, thereby extending the main circulation flow MC to the downstream side and promoting the fire transfer, thereby improving the flame holding property.

  As described above, according to the gas turbine combustor according to the present invention and the gas turbine engine equipped with the combustor, the mixing of air and fuel supplied from the main burner 4 is promoted to generate a uniform fuel mixture. In addition, while reducing emissions of NOx and the like, it is possible to prevent backfire and improve the reliability of the gas turbine engine.

  It should be noted that the present invention is not limited to the configuration of the above-described embodiment, and can be appropriately modified or improved within a scope not departing from the gist of the present invention. Are also included in the scope of rights of the present invention. For example, the above embodiments and reference embodiments may be combined with each other.

1, 31, 41, 51 Gas turbine combustor 2 Combustion cylinder 3 Pilot burner 4 Main burner 5 Pilot nozzle 6, 15 Fuel injection hole 7 Pilot nozzle outer cylinder 8 Pilot swirler 9 Pilot cone 11 Main nozzle 12 Premix nozzle 13 First Next mixing area 16 Main swirler (swirl flow generating means)
18 Annular Extension Nozzle 19 Face Plate 20 Spout 21 Secondary Mixing Region 22 Shrinking Portions 25, 26 Annular Gap (Air Introducing Means)
29, 30 Film air swirler (film air swirl means)
A Compressed air C Center axis C1, C2, C3, C4 of combustion cylinder Pitch circle F1, F2 Fuel FA Film air M1, M2 Fuel mixture P Pitch circle of premix nozzle

Claims (6)

A pilot burner disposed along the central axis of the combustion cylinder;
A plurality of main burners arranged to surround the pilot burner;
A plurality of cylindrical premixing nozzles respectively provided in the plurality of main burners and forming a primary mixing region therein;
The premixing nozzle has a continuous annular shape along the circumferential direction of the pitch circle, the outlet side of each of the plurality of premixing nozzles is connected, a secondary mixing region is formed therein, and on the downstream side An annular extension nozzle having an open spout,
It comprises a,
A connecting part between the premixing nozzle and the annular extension nozzle is provided with a contraction part for reducing the flow of the fuel mixture flowing from the premixing nozzle to the annular extension nozzle,
The annular extension nozzle has an annular outer peripheral wall surface and an annular inner peripheral wall surface along the circumferential direction of the pitch circle,
The contracted portion has a radial direction between the outer peripheral wall surface and the inner peripheral wall surface, with the outer peripheral wall surface facing inward in the radial direction of the pitch circle, and the inner peripheral wall surface inward in the radial direction outer side of the pitch circle. The gas turbine combustor is characterized in that the size of is reduced.   2. The gas turbine combustor according to claim 1, wherein the plurality of premixing nozzles are each provided with a swirl flow generating means for causing swirl flow in the same rotation direction. At least one of the connecting portion between the premixing nozzle and the annular extension nozzle or the annular extension nozzle itself introduces air flowing around the main burner into the annular extension nozzle, and the introduced air gas turbine combustor according to claim 1 or 2, characterized in that the air introducing means for forming a film air on the inner wall surface of said annular extension nozzle. The gas turbine combustor according to claim 3 , wherein the air introduction unit further includes a film air swirl unit that generates a swirl flow in the film air. The air introduction means introduces the introduced film air into the inner wall surface of the annular extension nozzle after flowing for a predetermined length along the outer wall surface of at least one of the premixing nozzle or the annular extension nozzle. The gas turbine combustor according to claim 3 , wherein the gas turbine combustor is configured as described above. A compressor that compresses air, the gas turbine combustor according to any one of claims 1 to 5 that combusts the air compressed in the compressor, and expansion of combustion gas ejected from the gas turbine combustor. A gas turbine engine comprising a driven turbine.

Images