JP2009192175A - Combustor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact combustor achieved in NOx reduction. <P>SOLUTION: The combustor includes a pilot nozzle 21 installed a shaft core of the combustor 1 to carry out diffusion combustion, a plurality of main nozzles 22 installed in an outer circumference side of the pilot nozzle 21 at intervals in a circumference direction and carrying out premix combustion, one inner tube 2a surrounding the pilot nozzle 21 and each main nozzle 22, and an outer tube coaxially surrounding the inner tube 2a from the outside and formed with a compressed air passage 6 between its inner circumference face and an outer circumference face of the inner tube. Compressed air flowing in the compressed air passage 6 is introduced in the pilot nozzle 21 with a flow direction substantially reversed in an end of the inner tube 2a. A flow control means for increasing a flow rate of a combustor 1 inner circumference side of the passage more than a flow rate of an outer circumference side is provided in the compressed air passage 6. A straightening vane 51 formed with holes 55, 56 can be given as the flow control means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a combustor for a gas turbine, and more particularly, to a combustor having a structure for reducing drift and turbulence of an air flow flowing inside the combustor.

  In order to reduce the NOx in the gas turbine combustor, it is important not to generate a local high fuel concentration by controlling the fuel distribution, and it is necessary to make the fuel concentration uniform. For this purpose, it is important to increase the amount of main air through which most of the fuel passes and to make it uniform.

Conventionally, a combustor has been disclosed in which mainstream air from a passenger compartment is turned 180 degrees to guide mainstream air to a main premixing nozzle (see, for example, Patent Document 5). In such a combustor, in order to eliminate the uneven distribution of the flow due to flow separation, etc., a rectifying plate is provided at the inlet, and two turning vanes are provided at the turning point, or from the combustion mixing point to the 180 degree turning point. By making the commutation distance long enough, the flow and concentration in the combustion region are made uniform.
JP 2007-232348 A

  However, the conventional structure causes an increase in weight and cost as the length of the combustor increases, and the turning portion is complicated, so that it is not effective for making the combustor compact. On the other hand, when the distance from the turning part to the fuel mixing point is shortened, there is a problem that the amount of NOx generated due to the worsening of the uneven distribution of air increases as an exhaust event.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a combustor that is compact and realizes NOx reduction.

  The present invention provides a pilot nozzle that is installed in the axis of a combustor and performs diffusion combustion, a main nozzle that is installed in a circumferential direction at an outer peripheral side of the pilot nozzle and that performs premix combustion, and the pilot nozzle And an inner cylinder that surrounds each main nozzle, and an outer cylinder that surrounds the inner cylinder substantially coaxially from the outside, and a compressed air flow path is formed between the inner peripheral surface and the outer peripheral surface of the inner cylinder. A compressed gas flow path in which the compressed air flowing through the compressed air flow path is introduced into the pilot nozzle after the flow direction is substantially reversed at the end of the inner cylinder. A flow rate adjusting means for making the flow rate on the inner peripheral side of the combustor larger than the flow rate on the outer peripheral side is provided.

If the holes provided in the current plate are uniform, the flow has no distribution in the radial direction of the combustor. In such a state, when the flow direction is substantially reversed, a low speed region is formed by peeling or the like inside the flow path reversal point downstream side. Therefore, when the combustor length is short, the rectification distance is shortened and the flow rate on the inner peripheral side tends to decrease.
According to the configuration of the present invention, the flow rate in the radial direction can be made uniform by the flow rate adjusting means. Thereby, the flow velocity distribution is given in the radial direction, and the velocity of the mainstream air in the radial direction downstream is made uniform.

  In the above invention, the compressed air flow path is provided with a rectifying plate as the flow rate adjusting means by blocking the flow path, and the rectifying plate sandwiches the rectifying plate between the upstream side and the downstream side of the flow path. A plurality of holes communicating with each other may be provided, and the diameter of the hole on the inner peripheral side may be larger than the diameter of the hole on the outer peripheral side.

  As described above, by arranging the large holes and the small holes in the rectifying plate, local speed non-uniformity occurs, and disturbance increases on the downstream side of the large holes. As a result, momentum exchange is activated, and the tendency of separation at the time of channel inversion is suppressed. In particular, by configuring the diameter of the hole located on the inner peripheral side of the combustor to be larger than the diameter of the hole positioned on the outer peripheral side, the flow rate in the radial direction can be made uniform.

  In the above invention, the compressed air passage is provided with a rectifying plate as the flow rate adjusting means by blocking the passage, and the inner peripheral side of the rectifying plate includes an upstream side and a downstream side of the rectifying plate. It is good also as providing the slit which connects these.

By providing the slits in the current plate where the speed deficit occurs, the flow rate increases, and the flow rate in the radial direction can be made uniform. In addition, such slits cause local speed non-uniformity and increase turbulence downstream. As a result, the exchange of momentum is activated, and the separation tendency on the downstream side of the flow path inversion portion is also suppressed.
A support rib that supports the inner cylinder to the outer cylinder is provided, and the rectifying plate is provided with a slit that communicates the upstream side and the downstream side of the rectifying plate in the vicinity of the support rib. Good. In particular, slits may be provided not only on the inner peripheral side of the current plate but also on the outer peripheral side and on the left and right sides of the support ribs. It may be set as appropriate according to the flow of the compressed air which part is specifically provided with the slit.

  In the above invention, the compressed air channel may be provided with a top hat nozzle at a position where the channel is substantially reversed.

  More specifically, the attachment angle, that is, the turn angle of the top hat nozzle is 0 degree or more and less than 90 degrees on the downstream side of the mainstream air with reference to the direction perpendicular to the flow direction of the mainstream air. In the prior art, a low speed region is formed by peeling or the like on the downstream side of the portion where the flow path is reversed. Therefore, when the combustor length is short, the rectification distance is shortened and the flow rate on the inner peripheral side tends to decrease. In this configuration, compressed air is mixed by a top hat nozzle provided at a position where the flow path is substantially reversed, and flow separation is suppressed. In other words, the momentum exchange is activated by the vortex generated downstream of the top hat nozzle, so that there is an effect of suppressing the separation region generated on the inner peripheral side when the flow path is reversed.

  In the above invention, the compressed air flow path is provided with a turning vane for guiding the fluid in the reversing flow path facing the inner cylinder edge, and the flow of the fluid is agitated on the back side of the turning vane. A stirrer may be provided.

  The turning vane reduces the pressure loss by bending the flow without separation as its role. Although such a clean flow is ideal, since the occurrence of turbulence is small, the force for mixing the fuel is small. For this reason, in the conventional combustor, the fuel concentration tends to locally increase downstream of the fuel mixing location, and the NOx concentration sometimes increases. In particular, since the flow on the back side of the turning vane is considered to be gently bent without separation, the turbulence is small compared to the ventral side of the turning vane, and the fuel mixing force is weak on the downstream side. According to this configuration, since the stirrer is provided on the back side of the turning vane, fuel mixing on the downstream side is promoted, and the fuel concentration is made uniform.

  In the above invention, a slit that communicates the back side and the abdomen side of the turning vane may be provided at the downstream end of the turning vane.

  Since the ventilating side of the turning vane tends to flow toward the outer peripheral side due to centrifugal force, the flow from the inner peripheral side of the turning vane to the outer peripheral side is generated by providing the slit. As a result, mixing on the back side of the turning vane is promoted, and the fuel concentration is made uniform.

  According to the present invention, it is possible to reduce NOx while reducing the axial length of the combustor by suppressing the separation of compressed air and making the fuel concentration uniform.

[First Embodiment]
Next, embodiments of the present invention will be described with reference to the drawings.
First, the combustor which concerns on 1st Embodiment is demonstrated using FIG. As shown in FIG. 1, the combustor 1 according to the present embodiment is installed along the axial center of the combustor 1 and performs diffusion combustion so that the combustor 1 is equally spaced in the circumferential direction on the outer peripheral side of the pilot nozzle 21. A plurality of main nozzles 22 that perform premix combustion, a pilot cone 23 that is installed so as to cover the front end side of the pilot nozzle 21, and a main burner 24 that is installed so as to cover the front end side of the main nozzle 22. A pilot swirler 25 installed between the outer wall of the pilot nozzle 21 and the inner wall of the pilot cone 23, and a main swirler 26 installed between the outer wall of the main nozzle 22 and the inner wall of the main burner 24.

  The combustor shown in FIG. 1 is fitted to the inner cylinder 2a and an inner cylinder 2a that 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. And a tail cylinder 2b that guides combustion gas from the pilot nozzle 21 and the main nozzle 22 to a turbine side (not shown), and an outer cylinder 2c that is substantially coaxial with the inner cylinder 2a and surrounds the inner cylinder 2a substantially coaxially from the outside. A rear wall 2d for closing the downstream of the outer cylinder 2c.

A compressed air flow path 6 is formed between the inner cylinder 2a and the outer cylinder 2c. The inner cylinder 2a includes a 180-degree turning portion 8 that substantially reverses the flow direction of the compressed air flow path 6 so as to go around the inner cylinder 2a at the end of the inner cylinder 2a. The radially outer wall portion of the 180-degree turning portion 8 bulges radially outward, and the portion corresponding to the edge of the inner tube 2a is shown in FIG. It is a smooth curve connecting the outer peripheral surface and the inner peripheral surface of 2a. More specifically, as shown in FIG. 2, the tapered portion 53a that is closer to the inner wall of the outer cylinder 2c from the upstream tip toward the downstream side, and the outer cylinder 2c on the downstream side of the tapered portion. A flat portion 53b having a constant distance from the inner wall and a semicircular portion 53c having a substantially semicircular cross section at the downstream end are provided. And the part where the inclination of the upstream of the taper-shaped part 53a starts, and the connection part of the taper-shaped part 53a and the flat part 53b are made into the rounded shape smoothly.
As described above, since the 180-degree turning portion 8 is configured, the outer wall of the 180-degree turning portion 8 is configured to approach the inner peripheral surface of the outer cylinder 2c toward the downstream side. The flow passage cross-sectional area of the compressed air formed between the peripheral surface and the outer peripheral surface of the 180-degree turning portion 8 is gradually narrowed toward the downstream. Thereby, the flow of compressed air is restrict | squeezed and the uniformity of the circumferential direction of a combustor will be given with respect to the flow in the downstream of the 180 degree | times turning part 8. FIG.

  Further, as shown in the cross-sectional view of FIG. 1, the back wall 2 d is an arc-shaped portion whose outer peripheral side is a curved surface with respect to the 180-degree turning portion 8, and the inner peripheral side is flat with respect to the 180-degree turning portion 8. The inner wall surface is a mortar-shaped concave curved surface. At this time, the curvature of the arc-shaped portion is a curvature corresponding to the outer peripheral surface side of the semicircular portion 53c of the 180-degree turning portion 8, and the inner wall surface of the arc-shaped portion of the back wall 2d and the semicircle of the 180-degree turning portion 8 The distance from the outer wall surface of the shape portion 53c is constant. Further, a connecting portion between the arc-shaped portion and the flat portion in the back wall 2d is formed on an extension line in the axial direction from the downstream end of the semicircular portion 53c in the 180-degree turning portion 8.

  In this way, by configuring the back wall 2d, the cross-sectional area between the inner wall surface of the arc-shaped portion of the back wall 2d and the outer wall surface of the semicircular portion 53c of the 180-degree turning portion 8 is set to the inner wall of the outer tube 2c. It can be made constant with an area equal to the cross-sectional area of the flat portion 53b of the 180 degree turning portion 8. Thereby, the compressed air which flows between the outer wall of the 180 degree | times turning part 8 and the inner wall of the outer cylinder 2c can be smoothly guide | induced to the inner side of the 180 degree | times turning part 8. FIG.

  A rectifying plate (flow rate adjusting means) 51 is provided in the vicinity of the inlet of the compressed air channel 6. 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 is 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. Is a perforated plate formed in large numbers. 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. As shown in the front view of FIG. 3A, the ribs 52 are provided radially with respect to the axis of the combustor 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. Also, 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 and are connected to the outer cylinder 2c to support the inner cylinder 2a.

  As shown in the cross-sectional view of FIG. 3B, the rib 52 is formed so as to protrude from the fixing member 52a to the inner cylinder 2a and to be fixed to the outer peripheral side of the rectifying plate 51. A plate-like member 52b in contact with the cylinder 2a. The fixing member 52a has a columnar structure with a semicircular cross section protruding on the upstream side and the downstream side of the rectifying plate 51, and internally includes a threaded hole through which the bolt 52c is inserted. On the upstream side of the fixing member 52a, a recess 52d is provided so that the head portion of the bolt 52c is embedded. After the bolt 52c is inserted, the recess 52d is embedded with a metal component to form a flat end surface.

  Further, as shown in the cross-sectional view of FIG. 3B, the outer cylinder 2c is provided with a rib connecting member 52e having a substantially columnar shape in the axial direction, which is connected to the fixing member 52a of the rib 52 on the inner wall thereof. The rib connecting member 52e includes a screw hole into which the bolt 52c is inserted. Thereby, the bolt 52c that penetrates the screw hole of the fixing member 52a is inserted into the screw hole of the rib connecting member 52e, and the fixing member 52a is fixed to the rib connecting member 52e. The rib 52 is fixed to the outer cylinder 2c. In addition, by making the downstream end face a curved surface having a substantially ¼ spherical shape, it is possible to minimize the disturbance of the flow of compressed air.

  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. Accordingly, the length of the pilot nozzle 21 and the main nozzle 22 in the axial direction is made uniform by uniformizing the compressed air flowing through the inner cylinder 2a by the configuration of the back wall 2d, the 180-degree turning portion 8, and the turning vane 54 described later. Since the length can be shortened, a support column connected to the pilot nozzle 21 that supports the downstream side of the main nozzle 22 is not required. 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.

  A ring-shaped turning vane 54 is provided in the vicinity of the upstream end portion of the inner cylinder 2 a so as to cover the space between the main nozzles 22. The turning vane 54 is disposed inside the inner cylinder 2a and in the vicinity of the 180-degree turning portion 8, and the axial position of the main nozzle 22 from the radially outer side to the downstream side from the upstream side toward the downstream side. It is formed of a single plate bent up to. The curvature of the turning vane 54 is formed to be equal to the inner wall surface of the semicircular portion 53c of the 180 degree turning portion 8. Further, the turning vane 54 is an arc-shaped plate that connects the side surfaces of the main nozzle 22. By the turning vane 54 configured as described above, the compressed air rotated 180 degrees along the 180 degree turning 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 180-degree turning 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 180-degree turning portion 8 is converted into the 180-degree turning portion. After being rectified by the taper-shaped part 53 a of 8, it is turned 180 degrees by the 180-degree turning part 8. Then, it is rectified by the turning vane 54 and guided to the pilot cone 23 and the main burner 24.

  Next, the current plate 51 which is a characteristic configuration in the present embodiment will be described. As shown in the front view seen from the downstream side of the outer cylinder 2c in FIG. 3A, the rectifying plate 51 covers the inlet of the compressed air flow path 6 between the outer wall of the inner cylinder 2a and the inner wall of the outer cylinder 2c. While having a ring-shaped configuration, a large number of holes are formed penetrating in the axial direction. As shown in FIG. 3A, the diameter of the hole 55 on the inner peripheral side is larger than the diameter of the hole 56 formed on the outer peripheral side. That is, the mainstream air flow rate on the inner peripheral side is configured to be larger than that on the outer peripheral side.

  In FIG. 4, the flow of the mainstream air at the time of using the baffle plate 51 which concerns on this embodiment was shown. If the holes provided in the rectifying plate are uniform as in the prior art, the flow has no distribution in the radial direction of the combustor 1. In such a state, the flow that bends through the 180 ° turning portion 8 forms a low speed region by peeling or the like, as indicated by reference numeral 100 in FIG. Therefore, when the combustor length is short, the rectification distance is shortened and the flow rate on the inner peripheral side tends to decrease.

In the rectifying plate 51 according to the present embodiment, by providing the hole 55 having a large diameter on the inner peripheral side, the flow rate on the inner peripheral side increases, and the flow rate in the radial direction becomes uniform. That is, the current plate 51 of the present embodiment functions as a flow rate adjusting unit.
In addition, by arranging the large holes and the small holes in a mixed manner, local uneven speed occurs, and the disturbance increases on the downstream side of the large holes. As a result, the momentum exchange is activated and the peeling tendency in the 180 degree turning portion 8 is also suppressed.

  Thus, according to the combustor of the present embodiment, the flow velocity distribution is given in the radial direction, and the separation is suppressed by promoting the turbulence. As a result, the velocity of the mainstream air in the radial direction and the mixing property can be improved downstream of the 180-degree turning portion 8 (upstream of the main premixing nozzle). Thereby, NOx reduction can be performed.

  In the above-described embodiment, the inner diameter side hole diameter of the rectifying plate 51 is configured to be larger than the outer diameter hole diameter, but the inner diameter side may be changed to the inner diameter side or the outer diameter side may be made larger. Further, the pressure loss adjustment may be performed by changing the thickness of the rectifying plate 51.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. The overall configuration is the same as that of the first embodiment, and the same reference numerals are used for the same configurations, and the description thereof is omitted.
FIG. 5 shows a partial front view of the current plate 152 according to the present embodiment. The rectifying plate 152 of the present embodiment is annular, and an outer slit 153 is formed as a gap between the outer cylinder 2c along the outer peripheral edge, and as a gap between the inner cylinder 2a along the inner peripheral edge. An inner slit 154 is formed. The outer slit 153 and the inner slit 154 are flow paths that penetrate the rectifying plate 152 in the axial direction of the flow path. In addition, rib vicinity slits 155 are respectively provided on the left and right sides of the rib 52. The rib vicinity slit 155 is a flow path that penetrates the rectifying plate 152 in the axial direction of the flow path, and is provided over the entire length in the radial direction.

  FIG. 6 shows the flow of mainstream air when the rectifying plate 152 according to the present embodiment is used. If the holes provided in the rectifying plate 152 are uniform as in the prior art, the momentum supply to the low speed region near the wall surface and the velocity deficit region formed downstream of the structure such as the rib 52 is not sufficient. For this reason, the flow that bends through the 180 degree turning portion 8 with the velocity deficit in the vicinity of the wall surface or the rib 52 in this way causes unevenness in the flow, and induces fuel density, thereby improving combustion stability and exhaust gas characteristics. make worse.

  In the present embodiment, the slits are provided on the inner peripheral side, the outer peripheral side, and the vicinity of the rib 52 of the rectifying plate 152 in which the speed deficiency occurs, so that the flow rate is increased and the above problems are solved. In addition, such slits cause local speed non-uniformity and increase turbulence downstream. As a result, momentum exchange is activated, and the tendency to peel off at the 180 ° turning portion 8 is also suppressed.

  As described above, according to the combustor of the present embodiment, the rectifying plate 152 according to the present embodiment is provided with the slit, thereby eliminating the speed deficit that occurs in the vicinity of the wall surface and the support in the rectifying plate 152. As a result, it is possible to realize the uniform velocity of the mainstream air and the improvement of the mixing property downstream of the 180 degree turning portion (upstream of the main premixing nozzle).

  In particular, the inner slit 154 may be provided only on the inner peripheral side of the current plate. It may be set as appropriate according to the flow of the compressed air which part is specifically provided with the slit.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. The overall configuration is the same as that of the first embodiment, and the same reference numerals are used for the same configurations, and the description thereof is omitted.
As shown in FIG. 7, the top hat nozzle 160 is provided in the middle of the 180 degree turning part. The top hat nozzle 160 is a fuel nozzle for premixed combustion that burns after mixing the top hat fuel gas and compressed air further upstream than the case of the main nozzle 22 for the purpose of reducing NOx and the like. A plurality of nozzles are provided on the outer peripheral side of the main nozzle 22.

  The inner peripheral part of the 180 degree turning part 8 has a partial circular shape in a cross-sectional shape along the axis of the combustor as shown in the figure, and smoothly changes the direction of the flow path by 180 degrees. In the present embodiment, the top hat nozzle 160 is a cylinder having a diameter of 10 mm, and is provided along the radial direction of the circular shape of the semicircular portion 53c. A gap 161 is formed between the periphery.

  The nozzle installation position needs to be upstream of the peeling point, which will be described later, and the attachment angle with respect to the 180-degree turning portion 8, that is, the turn angle, is based on the direction perpendicular to the flow direction of the mainstream air. It is θ (0 degree or more and less than 90 degree) on the downstream side of. The size of the gap 161 is about 0.5 to 2.0 times the thickness Dp of the top hat nozzle.

  In the prior art, the top hat nozzle is provided in an intermediate region between the current plate and the 180-degree turning portion 8. In the prior art, the flow that bends through the 180-degree turning portion 8 forms a low speed region by peeling or the like, as indicated by reference numeral 100 in FIG. Therefore, when the combustor length is short, the rectification distance is shortened and the flow rate on the inner peripheral side tends to decrease.

  In the present embodiment, the separation of the flow is suppressed by the mixing effect by the top hat nozzle 160. That is, the momentum exchange is activated by the vortex generated downstream of the top hat nozzle 160, so that there is an effect of suppressing the separation region generated in the inner periphery of the turn of the 180-degree turning portion 8 whose direction is greatly changed. In addition, by appropriately securing the gap 161 between the top hat nozzle 160 and the turn inner periphery within the above-described range, a separation region in which disturbance from the gap occurs downstream of the turn inner periphery can be more effectively suppressed. . Further, by providing the top hat nozzle 160 in the middle of the 180 degree turning portion 8, the distance between the current plate and the 180 degree turning portion 8 can be shortened, and the functions of the top hat nozzle 160 and the 180 degree turning portion 8 are integrated. This makes it possible to reduce the size of the combustor.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described. The overall configuration is the same as that of the first embodiment, and the same reference numerals are used for the same configurations, and the description thereof is omitted.
As shown in FIG. 8, the turning vane 54 has a pin-like stirrer 170 projecting radially inward on the back side (that is, radially outward of the compressed air flow path 6 that turns 180 degrees). Is provided. A plurality of stirrers 170 are provided in a substantially uniform manner along the circumferential direction.

The turning vane 54 reduces the pressure loss by bending the flow without separation as its role. Although such a clean flow is ideal, since the occurrence of turbulence is small, the force for mixing the fuel is small. For this reason, in the conventional combustor, the fuel concentration tends to increase locally downstream of the fuel mixing point, and the NOx concentration sometimes increases. In particular, since it is considered that the flow on the back side of the turning vane 54 is gently bent without separation, the turbulence is smaller than that on the abdominal side of the turning vane 54, and the fuel mixing force is weak on the downstream side.
In the present embodiment, the pin-shaped stirrer 170 is provided on the back side of the turning vane 54, so that the fuel mixing on the downstream side is promoted and the fuel concentration is made uniform. As a result, NOx reduction can be realized.

[Fifth Embodiment]
Next, a fifth embodiment of the present invention will be described. The overall configuration is the same as that of the first embodiment, and the same reference numerals are used for the same configurations, and the description thereof is omitted.
In the present embodiment, as in the fourth embodiment, fuel mixing is promoted with respect to the flow on the back side of the turning vane by increasing the disturbance on the back side of the turning vane.
That is, as shown in FIGS. 9A and 9B, a notch (slit) 172 is provided along the flow path direction at the downstream end of the turning vane 171 of the present embodiment. The notches 172 communicate the abdominal side and the back side of the turning vane 171, and a plurality of notches 172 are provided at intervals along the circumferential direction of the turning vane 171. The other structure of the turning vane 171 is the same as that of the turning vane 54 of the first embodiment, and a description thereof is omitted.

  Since the ventilating side of the turning vane 171 tends to flow toward the outer peripheral side due to centrifugal force, by providing the notch 172, a flow from the inner peripheral side of the turning vane toward the outer peripheral side occurs. As a result, as shown by arrows in FIGS. 9A and 9B, mixing on the back side of the turning vane is promoted, and the fuel concentration is made uniform. As a result, NOx reduction can be realized.

It is sectional drawing in the plane along the axis | shaft of the combustor which concerns on 1st Embodiment of this invention. It is the elements on larger scale which showed the 180 degree | times turning part vicinity of FIG. It is the figure which showed the baffle plate of the combustor, (a) The figure seen from the axial direction, (b) The elements on larger scale of FIG. It is sectional drawing which showed the flow of the mainstream air at the time of using the same baffle plate. It is a partial top view of the baffle plate used for the combustor which concerns on 2nd Embodiment of this invention. It is sectional drawing which showed the flow of the mainstream air at the time of using the same baffle plate. It is sectional drawing which showed the top hat nozzle vicinity used for the combustor which concerns on 3rd Embodiment of this invention. It is sectional drawing which showed the stirrer vicinity used for the combustor which concerns on 4th Embodiment of this invention. It is sectional drawing which showed the turning vane used for the combustor which concerns on 5th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Combustor, 2a ... Inner cylinder, 2c ... Outer cylinder, 6 ... Compressed air flow path, 8 ... 180 degree | times turning part, 51 ... Current plate (flow volume adjustment means), 52 ... Rib, 54 ... Turning vane, 55 ... Hole 56 ... hole 152 ... rectifier plate 153 ... outer slit 154 ... inner slit 155 ... rib vicinity slit 160 ... top hat nozzle 170 ... stirrer 171 ... turning vane 172 ... notch (slit)

Claims (6)

A pilot nozzle that is installed in the axial center of the combustor and performs diffusion combustion; a plurality of main nozzles that are installed at circumferential intervals on the outer peripheral side of the pilot nozzle and perform premix combustion; and the pilot nozzles and the main nozzles An inner cylinder that surrounds the nozzle, and an outer cylinder that surrounds the inner cylinder substantially coaxially from the outside and that has a compressed air flow path formed between the inner circumferential surface and the outer circumferential surface of the inner cylinder. In the combustor in which the compressed air flowing through the compressed air flow path is introduced into the pilot nozzle after the flow direction is substantially reversed at the end of the inner cylinder.
The combustor, wherein the compressed air flow path is provided with flow rate adjusting means for making the flow rate on the inner peripheral side larger than the flow rate on the outer peripheral side. The compressed air flow path is provided with a rectifying plate as the flow rate adjusting means by blocking the flow path,
The rectifying plate is provided with a plurality of holes that connect the upstream side and the downstream side of the passage across the rectifying plate, and the diameter of the hole on the inner peripheral side is larger than the diameter of the hole on the outer peripheral side. The combustor according to claim 1. The compressed air flow path is provided with a rectifying plate as the flow rate adjusting means by blocking the flow path,
The combustor according to claim 1, wherein a slit that communicates the upstream side and the downstream side of the rectifying plate is provided on an inner peripheral side of the rectifying plate.   The combustor according to any one of claims 1 to 3, wherein a top hat nozzle is provided in the compressed air flow path at a position where the flow path is substantially reversed. In the compressed air flow path, a turning vane for guiding the fluid in the flow path to be reversed is provided to face the inner cylinder edge,
The combustor according to any one of claims 1 to 4, wherein an agitator for agitating a flow of fluid is provided on a back side of the turning vane.   The combustor according to claim 5, wherein a slit that communicates the back side and the abdomen side of the turning vane is provided at a downstream end portion of the turning vane.

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