JP2012145312A - Combustor and gas turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a combustor, along with a gas turbine, which can be made compact, and also capable of uniformizing a fuel distribution.SOLUTION: The combustor includes: a combustion chamber to which fuel is mixed with air and the fuel is burnt; a nozzle 22 for spraying the fuel to the combustion chamber; an air passage 6 for supplying air to the combustion chamber while having a folding area for changing the air flow direction to be opposite; a suction port 12 for sucking part of the air flowing on the surface of the air passage 6 provided on an area of the folding area after changing the air flow direction to be opposite; a discharge port 13 for discharging air which is sucked at a downstream side of the air passage 6 than the suction port 12; and a bypass flow channel 11 for connecting the suction port 12 and the discharge port 13.

Description

  The present invention relates to a combustor in which fuel and air are mixed to burn the fuel, and a gas turbine including the combustor.

  In order to reduce NOx in the combustion exhaust from the gas turbine combustor, it is necessary to control the fuel distribution in the combustor so as not to produce a local high fuel concentration and to make the fuel concentration uniform. is important. For this purpose, it is necessary to increase the amount of main air through which most of the fuel passes and make it uniform.

  Patent Document 1 discloses a combustor 1 as shown in FIG. 1 in which mainstream air A supplied from a passenger compartment is turned by 180 ° and mainstream air is guided to a main nozzle 22 that performs premixed combustion. Has been. FIG. 1 is a cross-sectional view showing a combustor 1. In this case, in order to eliminate the uneven distribution of the flow due to the separation of the flow, the rectifying plate 51 is provided at the inlet of the mainstream air, the two turning vanes 54 of the 180 ° turning portion C are used, or the fuel from the 180 ° turning portion C is fueled. By making the rectification distance L to the mixing part D sufficiently long, the flow and concentration in the combustion region 10 are made uniform.

JP 2009-192175 A

  However, the conventional structure has problems such as an increase in weight and cost accompanying an increase in the length of the combustor and a complication of the 180 ° turning portion C, which is not effective for making the combustor compact. On the other hand, in order to reduce the cost and reduce the weight, it is effective to shorten the rectification distance L from the 180 ° turning portion C to the fuel mixing portion D. As a result, there was a problem that the unevenness of air distribution worsened and the amount of NOx generated increased.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a combustor and a gas turbine capable of achieving compactness and uniform fuel distribution.

In order to solve the above problems, the combustor and gas turbine of the present invention employ the following means.
That is, the combustor according to the present invention has a combustion chamber in which fuel and air are mixed and fuel is burned, a nozzle that injects fuel into the combustion chamber, and a folded region in which the air flow direction changes in the opposite direction. An air flow path for supplying air to the combustion chamber, a suction port for sucking a part of the air flowing in the surface of the air flow path provided in the area after the flow direction of the air changes in the folded area, and A discharge port that discharges air sucked on the downstream side of the air channel from the port, and a bypass channel that connects the suction port and the discharge port.

  According to this invention, fuel is injected from the nozzle into the combustion chamber, air is supplied from the air flow path to the combustion chamber, the fuel and air are mixed, and the fuel is combusted in the combustion chamber. Here, since the air flow path has a folded region where the air flow direction changes in the opposite direction, boundary layer separation near the wall surface occurs in a region of the folded region where the air flow direction is reversed, and the air flow direction is low. An area arises. On the other hand, according to this invention, the suction inlet is provided in the area | region after the flow direction of air changes on the contrary. Since the fluid velocity at the boundary layer peeling portion is low, the static pressure is higher than the area inside the suction port. Therefore, a part of the air flowing on the surface of the air flow path is sucked into the suction port. As a result, the low-speed fluid near the wall surface decreases, and the flow that has not lost the kinetic energy flowing away from the wall surface flows near the wall surface. Boundary layer peeling in can be prevented.

In the said invention, a suction inlet may be provided in the inner periphery of a return area | region among air flow paths.
In the area of the folded area where the air flow direction is opposite, the inner circumference of the folded area tends to be low speed. According to the present invention, part of the air flowing on the surface of the air flow path It is sucked into the suction port provided on the circumference. As a result, boundary layer peeling at the inner periphery of the folded region can be prevented.

In the above invention, the discharge port may be provided in the combustion chamber to discharge the sucked air to the surface of the combustion chamber.
According to this invention, the air sucked from the suction port and flowing through the bypass channel is discharged from the discharge port to the surface of the combustion chamber. At this time, since relatively low temperature air flows on the surface of the combustion chamber, the surface of the combustion chamber is cooled, and burning of the combustion chamber can be prevented.

In the above invention, the bypass flow path may be provided along the combustion chamber, and air flowing through the bypass flow path may cool the wall surface of the combustion chamber.
According to this invention, since the surface of the combustion chamber is cooled by the relatively low temperature air flowing through the bypass flow path provided along the combustion chamber, the combustion chamber can be prevented from being burned out.

In the above invention, the discharge port may be provided in the combustion chamber, and the air flowing through the bypass flow path may be used for fuel combustion.
According to the present invention, the air that has flowed through the bypass flow path is discharged from the discharge port provided in the combustion chamber and used for fuel combustion. Therefore, the air sucked from the air flow path is burned without being wasted. It is used as business air.

  Further, the combustor according to the present invention has a combustion chamber in which fuel and air are mixed to burn the fuel, a nozzle that injects fuel into the combustion chamber, and a folded region in which the air flow direction changes in the opposite direction. An air flow path for supplying air to the chamber, a suction port provided in the air flow path for sucking a part of the air, and a suction area provided in the area after the air flow direction is changed in the reversed area. It has a discharge port for discharging air sucked in the downstream side of the air flow channel from the port to the surface of the air flow channel, and includes a bypass flow channel connecting the suction port and the discharge port.

  According to this invention, fuel is injected from the nozzle into the combustion chamber, air is supplied from the air flow path to the combustion chamber, and fuel and air are mixed in the combustion chamber to burn the fuel. Here, since the air flow path has a folded region where the air flow direction changes in the opposite direction, boundary layer separation near the wall surface occurs in a region of the folded region where the air flow direction is reversed, and the air flow direction is low. An area arises. On the other hand, according to the present invention, the discharge port is provided in the region after the air flow direction has changed in the opposite direction, and air is discharged from the discharge port to the surface of the air flow path. As a result, since kinetic energy can be supplied to the low-speed fluid near the wall surface, boundary layer separation in the region after the air flow direction has changed in the opposite direction can be prevented.

  Furthermore, a gas turbine according to the present invention includes a compressor that introduces and compresses air, the above-described combustor that generates combustion gas by burning fuel with air supplied from the compressor, and a combustion gas from the combustor. And a turbine that receives the supply of.

  According to the present invention, in the combustor of the gas turbine, the air flow path is provided with the folded region where the air flow direction changes in the opposite direction, and the low speed region is in the region where the air flow direction is reversed. However, by providing the bypass flow path having the suction port and the discharge port, it is possible to prevent separation of the boundary layer in the region after the air flow direction is changed in the opposite direction.

  According to the present invention, it is possible to achieve compactness and uniform fuel distribution.

It is a cross-sectional view which shows a combustor. 1 is a partially enlarged cross-sectional view showing a combustor according to a first embodiment of the present invention. It is a partial expanded horizontal sectional view which shows the combustor which concerns on 2nd Embodiment of this invention. It is a partial expanded cross-sectional view which shows the combustor which concerns on 3rd Embodiment of this invention. It is a model figure which shows boundary layer suction. It is a model figure which shows a boundary layer blowing.

Embodiments according to the present invention will be described below with reference to the drawings.
[First Embodiment]
Hereinafter, the structure of the combustor which has the bypass flow path 11 which concerns on 1st Embodiment of this invention is demonstrated. The combustor of the present embodiment is obtained by adding a bypass channel 11 to the combustor 1 of FIG. 1 as shown in FIG. First, a combustor 1 to which this embodiment can be applied will be described with reference to FIG.
As shown in FIG. 1, the combustor 1 includes a pilot nozzle 21, a main nozzle 22, a pilot cone 23, a main burner 24, a pilot swirler 25, and a main swirler 26.

  The pilot nozzle 21 is installed along the axis of the combustor 1 and injects fuel to perform diffusion combustion. A plurality of main nozzles 22 are arranged at equal intervals in the circumferential direction on the outer peripheral side of the pilot nozzle 21 and inject fuel B. In the fuel mixing section D, the fuel and the compressed air supplied from the air inlet 3 are mixed, and premixed combustion is performed. Combustion is performed in the combustion chamber 10. The pilot cone 23 is installed so as to cover the tip side of the pilot nozzle 21. The main burner 24 is installed so as to cover the front end side of the main nozzle 22. The pilot swirler 25 is installed between the outer wall of the pilot nozzle 21 and the inner wall of the pilot cone 23. The main swirler 26 is installed between the outer wall of the main nozzle 22 and the inner wall of the main burner 24.

  The combustor 1 shown in FIG. 1 further includes an inner cylinder 2a, a tail cylinder 2b, an outer cylinder 2c, and a back wall 2d.

  The inner cylinder 2 a is substantially coaxial with the pilot nozzle 21 and is formed so as to cover the pilot nozzle 21 and the main nozzle 22 as a whole. The inner surface of the tail cylinder 2b is fitted to the outer periphery of the inner cylinder 2a, and guides the combustion gas generated by the pilot nozzle 21 and the main nozzle 22 to the turbine side (not shown). The outer cylinder 2c is substantially coaxial with the inner cylinder 2a, and surrounds the inner cylinder 2a from the outside while being separated from the inner cylinder 2a. The back wall 2d closes the downstream side of the outer cylinder 2c and the upstream side of the inner cylinder 2a.

The compressed air channel 6 is formed between the outer peripheral surface of the inner cylinder 2a and the inner peripheral surface of the outer cylinder 2c.
Moreover, the turn inner peripheral part 8 is formed in the edge part of the inner cylinder 2a. The turn inner peripheral portion 8 becomes an inner peripheral surface of the 180 ° turning portion C. The 180 ° turning portion C substantially reverses the flow direction of the compressed air so that the compressed air supplied from the air inlet 3 wraps around from the outside to the inside of the inner cylinder 2a. The flow of the mainstream air is as indicated by an arrow A in FIG. The radially outer wall portion of the turn inner peripheral portion 8 bulges radially outward, and the portion corresponding to the edge of the inner cylinder 2a is an inner portion in a plane including the axis as shown in FIG. It is a smooth curve connecting the outer peripheral surface and the inner peripheral surface of the cylinder 2a.

  Since the turn inner peripheral portion 8 is configured in this way, the outer wall of the turn inner peripheral portion 8 is configured to approach the inner peripheral surface of the outer cylinder 2c toward the downstream side. The channel cross-sectional area of the compressed air formed between the peripheral surface and the outer peripheral surface of the turn inner peripheral portion 8 is gradually narrowed toward the downstream. Thereby, the flow of compressed air is throttled, and the uniformity in the circumferential direction of the combustor 1 is given to the flow on the downstream side of the inner peripheral portion 8 of the turn.

  Further, as shown in the cross-sectional view of FIG. 1, the rear wall 2 d is an arc-shaped portion having a curved surface on the radially outer side of the turn inner peripheral portion 8, and the inner radial portion of the turn inner peripheral portion 8. By making the side flat, the inner wall surface is a mortar-shaped concave curved surface.

  A rectifying plate 51 is provided inside the compressed air flow path 6 in the vicinity of the air inlet 3. The rectifying plate 51 is a ring-shaped member that covers the upstream side of the outer cylinder 2 c in the compressed air flow path 6, and has a hole that communicates the upstream side and the downstream side of the compressed air flow path 6 with the rectifying plate 51 interposed therebetween. A large number of perforated plates.

  Adjacent to the downstream side of the rectifying plate 51, a plurality of ribs 52 for fixing the rectifying plate 51 are provided at equal intervals in the circumferential direction. By connecting the rib 52 to the outer wall surface of the inner cylinder 2a and the inner wall surface of the outer cylinder 2c, the inner cylinder 2a is fixed inside the outer cylinder 2c.

  The ribs 52 are provided radially with respect to the axis of the combustor 1 so that both ends thereof are in contact with the outer wall of the inner cylinder 2a and the inner wall of the outer cylinder 2c. A plurality of ribs 52 are provided, and the plurality of ribs 52 are arranged at equal intervals in the circumferential direction of the combustor 1 and are connected to the outer cylinder 2c, thereby supporting the inner cylinder 2a. .

  Thus, by providing the ribs 52 fixed to the outer cylinder 2c radially, the inner cylinder 2a can be suppressed and fixed in the circumferential direction by the ribs 52. Thereby, the downstream end of the main nozzle 22 can be supported by the main swirler 26 in the main burner 24 connected to the inner cylinder 2a.

  Therefore, the compressed air flowing through the inner cylinder 2a can be made uniform by the configuration of the back wall 2d, the turn inner peripheral portion 8, and the turning vane 54 described later. As a result, since the axial lengths of the pilot nozzle 21 and the main nozzle 22 can be shortened, a support column connected to the pilot nozzle 21 to support the downstream side of the main nozzle 22 becomes unnecessary. Further, since the compressed air is made to flow uniformly, the resistance by the rectifying plate 51 can be reduced as compared with the conventional case, and the pressure loss in the rectifying plate 51 can be suppressed.

  The turning vane 54 has a ring shape and is provided in the vicinity of the upstream end portion of the inner cylinder 2 a so as to cover the main nozzle 22 between the adjacent main nozzles 22. The turning vane 54 is disposed inside the inner cylinder 2a and in the vicinity of the turn inner peripheral portion 8, and is axially positioned from the radially outer side of the main nozzle 22 from the upstream side toward the downstream side. It is formed of a single plate bent up to.

  The turning vane 54 is an arc-shaped plate connected to the side surface of the main nozzle 22. By the turning vane 54 configured in this way, the compressed air rotated 180 degrees along the turn inner peripheral portion 8 and the back wall 2 d is guided to the pilot cone 23 and the main burner 24.

  The back wall 2d, the turn inner peripheral portion 8, and the turning vane 54 are configured as described above, so that the compressed air flowing between the outer cylinder 2c and the turn inner peripheral portion 8 is supplied from the rectifying plate 51. After being rectified before the end portion 8 of the inner periphery of the turn, it is turned 180 degrees at the 180 ° turning portion C. Then, it is rectified by the turning vane 54 and guided to the pilot cone 23 and the main burner 24.

  Next, the bypass passage 11 of the combustor according to the present embodiment will be described with reference to FIG. FIG. 2 is a partially enlarged cross-sectional view showing the combustor according to the first embodiment of the present invention, and shows the bypass flow path 11. FIG. 2 is a view taken along a plane along the axis of the combustor.

  The bypass flow path 11 is a pipe provided along the inner cylinder 2 a and has a suction port 12 and discharge ports 13 and 14. The suction port 12 is a region in the 180 ° turning portion C after the flow direction of the compressed air changes in the opposite direction, and is provided in the turn inner peripheral portion 8. The suction port 12 has an opening formed on the inner peripheral side of the inner cylinder 2 a and sucks a part of the air flowing through the compressed air flow path 6.

  In the region where the air flow direction is opposite in the 180 ° turning portion C, the inner circumference of the 180 ° turning portion C tends to be low speed. According to this embodiment, the air flowing on the surface of the compressed air channel 6 Is sucked into the suction port 12 provided on the inner periphery of the 180 ° turning portion C. When air is sucked from the suction port 12, boundary layer separation at the inner periphery of the 180 ° turning portion C can be prevented.

  The discharge port 13 is provided downstream of the suction port 12 in the compressed air passage 6 that supplies air to the combustion chamber 10 along the main nozzle 22. The discharge port 13 is formed with an opening on the inner peripheral side of the inner cylinder 2a. The suction port 12 and the discharge port 13 are connected by a pipe, and the air sucked in the suction port 12 flows through the pipe and is discharged from the discharge port 13. The air discharged from the discharge port 13 forms a thin air layer along the inner peripheral side wall surface of the inner cylinder 2a, cools the root of the outlet outer ring 27 as film cooling, and can prevent the wall surface from burning.

  The discharge port 14 is provided on the downstream side of the discharge port 13, and an opening is formed on the outer peripheral side of the inner cylinder 2a. The discharge port 14 discharges air other than the air discharged from the discharge port 13 among the air sucked by the suction port 12. The air discharged from the discharge port 14 passes through the outer peripheral side of the outlet outer ring 27 and the inner peripheral side of the outer cylinder 2 c and is discharged from the air supply port 15. And the air discharged | emitted from the air supply port 15 forms a thin air layer along the inner peripheral wall surface of the tail cylinder 2b, can cool the tail cylinder 2b as film cooling, and can prevent the wall surface from burning.

  FIG. 1 shows the flow of mainstream air in the combustor when the bypass flow path according to the present embodiment is not provided. In such a state, the flow of the 180 ° turning portion C is changed in direction by the turning vane 54 and passes through the vicinity of the turn inner peripheral portion 8, but since it is a large turn, in the vicinity of the turning inner peripheral portion 8, As indicated by reference numeral E, a low speed region is formed by boundary layer separation, and the flow rate on the inner peripheral side of the 180 ° turning portion C tends to decrease. As a result, mixing with the main fuel while maintaining the speed distribution causes the concentration of the fuel concentration to occur, and NOx tends to increase due to local high temperatures.

  On the other hand, in this embodiment, the suction port 12 connected to the bypass flow path 11 is provided in the region after the air flow direction has changed in the opposite direction. Since the fluid velocity at the boundary layer peeling portion is low, the static pressure is higher than the region inside the suction port 12. Therefore, a part of the air flowing on the surface of the compressed air channel 6 is sucked into the suction port 12. As a result, the low-speed fluid near the wall surface decreases, and the flow that does not lose kinetic energy flowing away from the wall surface flows near the wall surface, so the region after the air flow direction has changed in the opposite direction Boundary layer peeling in can be prevented. FIG. 5 shows a model for preventing boundary layer peeling by boundary layer suction.

  Therefore, by providing the bypass flow path 11 of the present embodiment, the speed of the mainstream air A in the radial direction on the downstream side of the 180 ° turning portion C and the upstream side of the main nozzle 22 is made uniform. be able to. As a result, the concentration distribution becomes uniform, and the generated NOx can be reduced.

  In addition, the suction port 12 provided in the turn inner peripheral part 8 in this embodiment may be provided with a plurality of holes in one place, and the shape of the suction port 12 includes several shapes such as a circular shape and a slit shape. The shape can be considered. Further, the arrangement and size of the suction ports 12 may be uniform in the circumferential direction, and are not necessarily uniform in the circumferential direction. For example, since the combustor 1 shown in FIG. 1 has a plurality of main nozzles 22, the air flow is uneven in the circumferential direction. Therefore, the arrangement and size of the suction port 12 may be adjusted in accordance with the arrangement of the main nozzle 22.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a partial enlarged cross-sectional view showing a combustor according to the second embodiment of the present invention, and shows a bypass flow path 31. FIG. 3 is a view taken along a plane along the axis of the combustor.
Unlike the multi-type combustor 1 shown in FIG. 1, the combustor shown in FIG. 3 is an annular type. That is, the combustor of the present embodiment injects fuel from the fuel injection hole into the air flowing from the upstream side or a mixture of air and fuel and applies a swirling force to create a swirling mixed airflow ( Swirl wing).

  A combustion burner 43 is inserted through the center of the combustor. Further, the compressed air flow path 40 located on the outermost side in the radial direction, the first flow path 41 located on the innermost side in the radial direction, and the compressed air flow path 40 and the first flow path 41 are positioned between the compressed air flow path 40 and the first flow path 41. The second flow path 42 is provided.

  The compressed air flow path 40 and the second flow path 42 are partitioned (partitioned) by a peripheral wall that forms the inner cylinder 44a, and the first flow path 41 and the second flow path 42 are a peripheral wall. Are partitioned (partitioned) by a hollow cylindrical intermediate ring 30 located on the inside in the radial direction. The intermediate ring 30 has a cylindrical shape, and the central axis is the same as the central axis of the combustion burner 43. A bypass channel 31 is provided in the intermediate ring 30.

  In the compressed air channel 40, a nozzle 33 having a premixing injection hole 33a for ejecting premixed fuel into the compressed air channel 40 projects. The premixing fuel injected from the premixing injection holes 33a is mixed with the air flowing in from the air inlet 39, and together with the air flowing in from the air inlet 39, the first flow path located on the downstream side. 41 and the second flow path 42.

  An inner ring swirler vane (swirl blade) 34 protruding toward the inside of the first flow path 41 is provided at the tip end portion (downstream end portion) of the combustion burner 43. A plurality of (for example, 16) inner ring swirler vanes 34 are arranged radially from the outer peripheral surface of the combustion burner 43 and along the axial direction of the combustion burner 43, and fuel ( An inner fuel ejection hole 34a for ejecting (inner fuel) is provided. The inner fuel injected from the inner fuel injection hole 34a is the air-fuel mixture that has passed through the first flow path 41 (the air flowing in from the air inlet 39 and the premixing fuel injected from the premixing injection hole 33a. And the mixture that has passed through the first flow path 41 is sent (supplied) to the combustion chamber 45 located on the downstream side. The inner ring swirler vane 34 imparts a swirling force to the air-fuel mixture that has passed through the first flow path 41, and turns this air-fuel mixture into a swirling mixed airflow.

  An outer ring swirler vane (swivel blade) 36 protruding toward the inside of the second flow path 42 is provided at the distal end portion (downstream end portion) of the intermediate ring 30. A plurality of outer ring swirler vanes 36 (for example, 16 sheets) are arranged radially from the outer peripheral surface of the intermediate ring 30 and along the axial direction of the intermediate ring 30, and fuel ( An outer fuel ejection hole 36a for ejecting (outer fuel) is provided. The outer fuel injected from the outer fuel injection hole 36a is the air-fuel mixture that has passed through the second flow path 42 (the air flowing in from the air inlet 39 and the premixing fuel injected from the premixing injection hole 25a. And the mixture that has passed through the second flow path 42 is sent (supplied) to the combustion chamber 45 located on the downstream side. Note that the outer ring swirler vane 36 applies a swirling force to the air-fuel mixture that has passed through the second flow path 42 to turn this air-fuel mixture into a swirling mixed airflow.

  The bypass channel 31 is a pipe provided along the length direction of the intermediate ring 30, and has a suction port 32 and a discharge port 33. The suction port 32 is a region after the flow direction of the compressed air changes in the 180 ° turning portion C in the opposite direction, and is provided in the intermediate ring 30. The suction port 32 is formed with an opening on the first flow path 41 side of the intermediate ring 30 and sucks a part of the air flowing through the compressed air flow path 40.

  In the region where the air flow direction is opposite in the 180 ° turning portion C, the inner circumference of the 180 ° turning portion C tends to be low speed. According to this embodiment, the air flows on the surface of the first flow path 41. Part of the air is sucked into the suction port 12 provided on the inner periphery of the 180 ° turning portion C. When air is sucked from the suction port 12, boundary layer separation at the inner periphery of the 180 ° turning portion C can be prevented.

  The discharge port 33 is provided on the downstream side of the suction port 32 in the first flow path 41 or the second flow path 42 for supplying fuel and air-fuel mixture. The discharge port 33 has an opening at the end of the intermediate ring 30 and on the combustion chamber 45 side. The suction port 32 and the discharge port 33 are connected by a pipe, and the air sucked through the suction port 32 flows through the pipe and is discharged from the discharge port 33.

  When the air sucked from the suction port 32 passes through the bypass channel 31, the air sucked from the suction port 32 cools the wall surface of the intermediate ring 30 heated by the combustion gas. The air discharged from the discharge port 33 is ejected from between the first flow path 41 and the second flow path 42 and is finally used as combustion air for burning fuel. Therefore, even if the air flowing in from the air inlet 39 passes through the bypass flow path 31, it is not wasted as combustion air.

  As described above, according to the second embodiment, similarly to the first embodiment, the suction port 32 connected to the bypass flow path 31 is provided in the region after the air flow direction has changed in the 180 ° turning portion C in the opposite direction. It has been. Since the fluid velocity at the boundary layer peeling portion is low, the static pressure is higher than the region inside the suction port 32. Therefore, a part of the air flowing on the surface of the first flow path 41 is sucked into the suction port 12. As a result, the low-speed fluid near the wall surface decreases, and the flow that does not lose kinetic energy flowing away from the wall surface flows near the wall surface, so the region after the air flow direction has changed in the opposite direction Boundary layer peeling in can be prevented.

  Therefore, by providing the bypass flow path 31 of the present embodiment, the speed of the mainstream air A in the radial direction on the downstream side of the 180 ° turning portion C can be made uniform. As a result, the concentration distribution becomes uniform, and the generated NOx can be reduced.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a partial enlarged cross-sectional view showing a combustor according to a third embodiment of the present invention, and shows a bypass flow path 61. FIG. 4 is a view taken along a plane along the axis of the combustor.
The combustor of the present embodiment is the multi-type combustor described in FIG. In the present embodiment, unlike the first embodiment, a bypass channel 61 is provided in the turn inner periphery 8. Since other points are the same as those of the first embodiment, detailed description thereof is omitted.

Hereinafter, the bypass flow path 61 according to the present embodiment will be described with reference to FIG.
The bypass flow path 61 is provided along the compressed air flow path 6 in the turn inner peripheral portion 8. The bypass channel 61 is, for example, tubular and has a suction port 62 and a discharge port 63. The suction port 62 is provided in the compressed air flow path 6 upstream of the 180 ° turning portion C. The suction port 62 has an opening formed on the outer peripheral side of the inner cylinder 2 a and sucks a part of the air flowing through the compressed air flow path 6.

  The discharge port 63 is an area after the flow direction of the compressed air in the 180 ° turning portion C is changed in the opposite direction, and is provided in the turn inner peripheral portion 8. The discharge port 63 is formed with an opening on the inner peripheral side of the inner cylinder 2a. The suction port 62 and the discharge port 63 are connected by a pipe, and the air sucked through the suction port 62 flows through the pipe and is discharged from the discharge port 63.

  In the region where the air flow direction is opposite in the 180 ° turning portion C, the inner circumference of the 180 ° turning portion C tends to be low speed. According to this embodiment, the air discharged from the suction port 62 is The air is discharged from the discharge port 63 provided on the inner periphery of the 180 ° turning portion C to the surface of the compressed air flow path 6. By discharging air from the discharge port 63, it is possible to prevent boundary layer peeling at the inner periphery of the 180 ° turning portion C.

  That is, in the present embodiment, the discharge port 63 connected to the bypass flow path 61 is provided in the region after the air flow direction has changed in the opposite direction, and air is discharged from the discharge port 63 to the surface of the compressed air flow path 6. Is done. As a result, since kinetic energy can be supplied to the low-speed fluid near the wall surface, boundary layer separation in the region after the air flow direction has changed in the opposite direction can be prevented. FIG. 6 shows a model for preventing boundary layer peeling by boundary layer blowing.

  Therefore, by providing the bypass flow path 61 of the present embodiment, the speed of the mainstream air A in the radial direction on the downstream side of the 180 ° turning portion C and the upstream side of the main nozzle 22 is made uniform. be able to. As a result, the concentration distribution becomes uniform, and the generated NOx can be reduced.

DESCRIPTION OF SYMBOLS 1 Combustor 2a, 44a Inner cylinder 2b Tail cylinder 2c Outer cylinder 2d Back wall 3,39 Air inlet 6,40 Compressed air flow path (air flow path)
8 Turn inner peripheral portion 10, 45 Combustion chamber 11, 31, 61 Bypass passage 12, 32, 62 Suction port 13, 14, 33, 63 Discharge port 15 Air supply port 21 Pilot nozzle 22 Main nozzle (nozzle)
30 Intermediate ring 41 1st flow path 42 2nd flow path 43 Combustion burner 54 Turning vane C 180 degree turning part (folding area)

Claims (7)

A combustion chamber in which fuel and air are mixed and the fuel is combusted;
A nozzle for injecting the fuel into the combustion chamber;
An air flow path for supplying the air to the combustion chamber while having a folded area where the flow direction of the air changes in the opposite direction;
A suction port that sucks a part of the air that flows in the surface of the air flow path that is provided in a region after the air flow direction is changed in the opposite direction in the folded region, and the air flow channel than the suction port A bypass passage for discharging the sucked air on the downstream side, and a bypass flow path connecting the suction port and the discharge port,
A combustor.   The combustor according to claim 1, wherein the suction port is provided in an inner periphery of the folded region in the air flow path.   The combustor according to claim 1 or 2, wherein the discharge port is provided in the combustion chamber and discharges the sucked air to a surface of the combustion chamber.   4. The combustor according to claim 1, wherein the bypass flow path is provided along the combustion chamber, and the air flowing through the bypass flow path cools a wall surface of the combustion chamber. 5.   The combustor according to any one of claims 1 to 4, wherein the exhaust port is provided in the combustion chamber, and the air flowing through the bypass flow path is used for combustion of the fuel. A combustion chamber in which fuel and air are mixed and the fuel burns;
A nozzle for injecting the fuel into the combustion chamber;
An air flow path for supplying the air to the combustion chamber while having a folded area where the flow direction of the air changes in the opposite direction;
A suction port that is provided in the air flow path and sucks a part of the air; and is provided in a region after the air flow direction is changed in the reversed region, and the air flow is more than the suction port. A bypass passage for discharging the air sucked on the downstream side of the passage to the surface of the air flow path, and connecting the suction opening and the discharge opening;
A combustor. A compressor that introduces and compresses air; and
A combustor according to any one of claims 1 to 6, wherein combustion gas is generated by burning fuel with air supplied from the compressor;
A turbine that receives a supply of combustion gas from the combustor;
A gas turbine comprising:

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