JP2023128681A - Exhaust system for gas turbine and gas turbine - Google Patents

Abstract

To provide an exhaust system for a gas turbine capable of suppressing an impact on a flow of exhaust gas in an exhaust duct, and the gas turbine.SOLUTION: An exhaust system for a gas turbine according to at least one embodiment of this disclosure includes: an annular exhaust duct that is connected to a downstream side of the turbine and to which combustion gas used for rotating the turbine is guided; and an extraction pipe for guiding part of compressed air extracted from a compressor to the exhaust duct. In a flowing direction of the compressed air, the extraction pipe includes a gradually increasing part of which flow passage cross section gradually increases toward an end part on a downstream side in the flowing direction. The end part on the downstream side does not project into an exhaust passage of the exhaust duct.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a gas turbine exhaust system and a gas turbine.

Generally, industrial gas turbines have a configuration in which a portion of the compressed air is extracted from the compressor during startup to improve the starting characteristics of the compressor, and the extracted air is released into the exhaust duct via a bleed pipe. is known (for example, see Patent Document 1).

Patent No. 5571015

However, in the gas turbine described in Patent Document 1, for example, the bleed pipe protrudes into the exhaust duct, which may disturb the flow of exhaust gas flowing inside the exhaust duct and increase pressure loss.

In view of the above-mentioned circumstances, at least one embodiment of the present disclosure aims to provide a gas turbine exhaust system and a gas turbine that can suppress the influence on the flow of exhaust gas in the exhaust duct.

(1) A gas turbine exhaust system according to at least one embodiment of the present disclosure includes:
an annular exhaust duct connected to the downstream side of the turbine, through which combustion gas that rotates the turbine is guided;
an air bleed pipe for guiding a part of the compressed air extracted from the compressor to the exhaust duct;
Equipped with
The air bleed pipe has a gradually increasing portion in which the cross-sectional area of the flow passage gradually increases as it goes toward the downstream end in the flow direction along the flow direction of the compressed air,
The downstream end portion does not protrude into the exhaust passage of the exhaust duct.

(2) The gas turbine according to at least one embodiment of the present disclosure includes:
a compressor that generates compressed air;
a combustor that generates combustion gas;
a turbine rotationally driven by combustion gas generated in the combustor;
A gas turbine exhaust system configured as described in (1) above;
Equipped with

According to at least one embodiment of the present disclosure, it is possible to suppress the influence on the flow of exhaust gas within the exhaust duct in a gas turbine.

1 is a diagram showing a schematic configuration of a gas turbine 1 according to some embodiments. It is a typical sectional view for explaining an example of an exhaust device. It is a typical sectional view for explaining another example of an exhaust device. It is a typical sectional view for explaining still another example of an exhaust device. 5 is a sectional view taken along the line VV in FIG. 4. FIG. 6 is a sectional view taken along the line VI-VI in FIG. 5. FIG. FIG. 5 is a cross-sectional view taken along the line VV in FIG. 4 for explaining still another example of the exhaust device. It is a typical sectional view for explaining still another example of an exhaust device. FIG. 5 is a cross-sectional view taken along the line VV in FIG. 4 for explaining still another example of the exhaust device. FIG. 9 is a sectional view taken along the line XX in FIG. 9; It is a typical sectional view for explaining still another example of an exhaust device.

Hereinafter, some embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present disclosure, and are merely illustrative examples. do not have.
For example, expressions expressing relative or absolute positioning such as "in a certain direction,""along a certain direction,""parallel,""orthogonal,""centered,""concentric," or "coaxial" are strictly In addition to representing such an arrangement, it also represents a state in which they are relatively displaced with a tolerance or an angle or distance that allows the same function to be obtained.
For example, expressions such as "same,""equal," and "homogeneous" that indicate that things are in an equal state do not only mean that things are exactly equal, but also have tolerances or differences in the degree to which the same function can be obtained. It also represents the existing state.
For example, expressions expressing shapes such as squares and cylinders do not only refer to shapes such as squares and cylinders in a strict geometric sense, but also include uneven parts and chamfers to the extent that the same effect can be obtained. Shapes including parts, etc. shall also be expressed.
On the other hand, the expressions "comprising,""comprising,""comprising,""containing," or "having" one component are not exclusive expressions that exclude the presence of other components.

First, the overall configuration of a gas turbine 1 according to some embodiments will be described with reference to FIG. 1 as an example. Here, FIG. 1 is a diagram showing a schematic configuration of a gas turbine 1 according to some embodiments.

The gas turbine 1 according to some embodiments includes a compressor 3 for generating compressed air, a combustor 4 for generating combustion gas by burning fuel using the compressed air, and a gas turbine driven by the combustion gas. a turbine 5 configured to

In the gas turbine 1, air taken into the compressor 3 passes through a plurality of stator blades and rotor blades provided in the compressor compartment and is compressed, thereby generating high-temperature and high-pressure air (compressed air). Ru.
The combustor 4 is supplied with fuel and high-temperature, high-pressure air from the compressor 3. In this combustor 4, fuel and air are mixed and combusted in the combustor compartment to generate combustion gas. When the gas turbine 1 is operating at partial load or at full load, the flow rate of fuel supplied to the combustor 4 is determined by the operating state and load of the gas turbine 1. For example, the fuel flow rate is determined based on at least one of the load of the gas turbine 1, the rotational speed (rotational speed), or the combustion gas temperature.
Combustion gas from the combustor 4 is introduced into the turbine 5 . This combustion gas passes through a plurality of stator blades and rotor blades arranged in the turbine casing, thereby rotating a rotor that is provided so as to penetrate the turbine casing and the compressor casing. When the gas turbine 1 is used for power generation, the rotation of the rotor causes a generator (not shown) connected to the rotor to generate power.
An exhaust duct 6 is connected to the downstream side of the turbine 5 and communicates with the turbine casing. Exhaust gas after driving the turbine 5 passes through an exhaust duct 6 and a chimney 7 connected to the downstream side of the exhaust duct 6 to be exhausted to the outside.

The gas turbine 1 further includes at least one bleed line 20 (20a to 20c) that bleeds air from the compressor 3.

The bleed air line 20 is connected to a cooling line 21 (21a to 21c). The cooling line 21 is arranged so as to guide at least a portion of the compressed air extracted from the compressor 3 via the air extraction line 20 to the turbine 5 as cooling air.

Further, the bleed air line 20 is connected to an exhaust line 24 (24a to 24c).
The exhaust line 24 is arranged to guide at least a portion of the compressed air extracted from the compressor 3 to the downstream side of the turbine 5, that is, to the exhaust duct 6 in FIG.

In the embodiment shown in FIG. 1, the bleed lines 20 include a high pressure bleed line 20a that bleeds air from the high pressure stage (outlet side) of the compressor 3, and an intermediate pressure bleed line 20b that bleeds air from the middle pressure stage (middle) of the compressor 3. and a low pressure bleed line 20c that bleeds air from the low pressure stage (inlet side) of the compressor 3.
The cooling line 21 is connected to a high-pressure extraction line 20a, which introduces compressed air into the high-pressure stage (inlet side) of the turbine 5, and an intermediate-pressure extraction line 20b, which is connected to the intermediate-pressure extraction line 20a of the turbine 5. It includes an intermediate pressure cooling line 21b that introduces compressed air to the stage (intermediate), and a low pressure cooling line 21c that is connected to the low pressure extraction line 20c and introduces compressed air to the low pressure stage (outlet side) of the turbine 5.
The exhaust line 24 includes a high pressure exhaust line 24a connected to a high pressure bleed line 20a and a high pressure cooling line 21a, an intermediate pressure exhaust line 24b connected to an intermediate pressure bleed line 20b and an intermediate pressure cooling line 21b, and a low pressure bleed line 20c. and a low pressure exhaust line 24c connected to the low pressure cooling line 21c.

In the conventional gas turbine, the bleed pipe that is the piping of the exhaust line 24 protrudes into the exhaust duct 6, which may disturb the flow of exhaust gas flowing through the exhaust duct 6 and increase pressure loss.
Further, inside the exhaust duct 6, a heat insulating material may be arranged for heat shielding. Depending on the operating conditions of the gas turbine, the flow velocity of compressed air discharged from the bleed pipe may increase, so if compressed air is inadvertently blown out from the bleed pipe within the exhaust duct, the insulation material inside the exhaust duct may There is a risk of damaging the product.

Therefore, in the gas turbine 1 according to some embodiments, the above-described problems are solved by configuring the exhaust system of the gas turbine 1 as follows.
FIG. 2 is a schematic cross-sectional view for explaining an example of the exhaust system 10 of the gas turbine 1.
FIG. 3 is a schematic cross-sectional view for explaining another example of the exhaust device 10.
FIG. 4 is a schematic cross-sectional view for explaining still another example of the exhaust device 10.
FIG. 5 is a sectional view taken along the line VV in FIG. 4, and for convenience of explanation, the heat insulating material 62 inside the exhaust duct 6 is omitted.
FIG. 6 is a sectional view taken along the line VI-VI in FIG.
FIG. 7 is a cross-sectional view taken along the line VV in FIG. 4 for explaining still another example of the exhaust system 10. For convenience of explanation, the heat insulating material 62 inside the exhaust duct 6 is not shown. It is omitted.
FIG. 8 is a schematic cross-sectional view for explaining yet another example of the exhaust device 10.
FIG. 9 is a cross-sectional view taken along the line VV in FIG. 4 for explaining still another example of the exhaust system 10. For convenience of explanation, the heat insulating material 62 inside the exhaust duct 6 is not shown. It is omitted.
FIG. 10 is a sectional view taken along the line XX in FIG.
FIG. 11 is a schematic cross-sectional view for explaining still another example of the exhaust device 10.

The exhaust system 10 according to some embodiments shown in FIGS. 2 to 11 includes an annular exhaust duct 6 connected to the downstream side of the turbine 5 and through which combustion gas (exhaust gas) that rotationally drives the turbine 5 is guided. , and a bleed pipe 25 for guiding a part of the compressed air bleed from the compressor 3 to the exhaust duct 6. The air bleed pipe 25 has a gradually increasing portion 250 in which the flow passage cross-sectional area gradually increases along the flow direction of the compressed air toward the exhaust duct side end 251 which is the downstream end in the flow direction. The exhaust duct side end portion 251 does not protrude into the exhaust passage 61 of the exhaust duct 6.

In the exhaust device 10 according to some embodiments described below with reference to FIGS. 2 to 11, the bleed pipe 25 is connected to the medium pressure exhaust line 24b, the medium pressure bleed discharge pipe 25b, or the low pressure exhaust line 24c. Although it is the low pressure bleed gas discharge pipe 25c, it may be the high pressure bleed gas discharge pipe 25a of the high pressure exhaust line 24a. In the following description, there will be cases where the intermediate pressure bleed discharge pipe 25b, the low pressure bleed discharge pipe 25c, and the high pressure bleed discharge pipe 25a are not particularly distinguished, and the intermediate pressure bleed discharge pipe 25b, the low pressure bleed discharge pipe 25c, and the high pressure bleed discharge pipe 25a. When these are collectively referred to, they are simply referred to as the bleed pipe 25.

In the exhaust device 10 according to some embodiments, a heat insulating material 62 for heat shielding is arranged inside the exhaust duct 6. The heat insulating material 62 preferably covers the outer periphery of at least a portion of the gradually increasing portion 250 of the bleed pipe 25, which will be described below.

In the exhaust device 10 according to some embodiments, the bleed pipe 25 extends along the central axis AX of the exhaust duct 6, and near the confluence with the exhaust duct 6, the bleed pipe 25 extends along the central axis AX of the exhaust duct 6. It is bent towards AX.
In the following description, the direction in which the central axis AX extends is also referred to as the axial direction. In the axial direction, the upstream side in the exhaust gas flow direction is referred to as the axial upstream side, or simply the upstream side, and the downstream side in the exhaust gas flow direction is referred to as the axial downstream side, or simply the downstream side.
Further, in the following description, the circumferential direction centered on the central axis AX is also simply referred to as the circumferential direction, and the radial direction centered on the central axis AX is also simply referred to as the radial direction.

Note that when describing the direction with respect to the air bleed pipe 25, the direction may be referred to as the upstream side in the flow direction or the downstream side in the flow direction based on the flow direction of the compressed air flowing through the air bleed pipe 25.
In the section where the bleed pipe 25 extends along the axial direction, the upstream side in the flow direction coincides with the axial upstream side, and the downstream side in the flow direction coincides with the axial downstream side.
That is, in the exhaust device 10 according to some embodiments, the bleed pipe 25 has an upstream region 25U that extends in the axial direction on the upstream side of the gradually increasing portion 250 described below in the flow direction.
The gradually increasing portion 250 of the bleed pipe 25, which will be described below, is arranged so as to move radially inward as it goes downstream in the axial direction.

As described above, the gradually increasing portion 250 of the air bleed pipe 25 is formed such that the flow passage cross-sectional area gradually increases toward the exhaust duct side end 251, which is the downstream end in the flow direction.
For example, in the examples shown in FIGS. 2, 3, and 11, the gradually increasing portion 250 has inner circumferential surfaces 250a of the gradually increasing portion 250 that are spaced apart from each other in the axial direction toward the exhaust duct side end 251. The flow path cross-sectional area is formed so as to gradually increase as the separation distance between them increases. That is, in the examples shown in FIGS. 2, 3, and 11, the gradually increasing portion 250 has an inner circumferential surface 250a that is spaced apart in the axial direction and is inclined in a tapered shape when viewed from the circumferential direction. ing.

For example, in the examples shown in FIGS. 4, 5, 8, and 9, the gradually increasing portion 250 is formed on the inner peripheral surface of the gradually increasing portion 250 that is spaced apart in the circumferential direction toward the exhaust duct side end 251. The passage cross-sectional area is formed so as to gradually increase as the circumferential distance between the 250b increases gradually. That is, in the examples shown in FIG. 4, FIG. 5, FIG. 8, and FIG. is inclined to.

Note that in the examples shown in FIGS. 2, 3, and 11, as in the examples shown in FIGS. The inner circumferential surfaces 250b of the gradually increasing portions 250 may be formed so that the circumferential distance between them gradually increases.
Similarly, in the examples shown in FIGS. 4, 5, 8, and 9, the gradually increasing portion 250 increases toward the exhaust duct side end 251, as in the examples shown in FIGS. , the inner peripheral surfaces 250a of the gradually increasing portions 250 are formed so that the distance in the axial direction gradually increases.

In the exhaust device 10 according to the several embodiments described above, as shown in FIGS. It does not protrude further inward in the radial direction. That is, in the exhaust device 10 according to the several embodiments described above, the exhaust duct side end portion 251 does not protrude into the exhaust passage 61 of the exhaust duct 6.

According to the exhaust device 10 according to the several embodiments described above, since the air bleed pipe 25 does not protrude into the exhaust passage 61 of the exhaust duct 6, it becomes difficult to disturb the flow of exhaust gas flowing inside the exhaust duct 6, and the exhaust The influence on the flow of exhaust gas within the duct 6 can be suppressed. Further, according to the exhaust device 10 according to the several embodiments described above, the flow velocity of the compressed air discharged from the bleed pipe 25 into the exhaust duct 6 decreases in the gradually increasing portion 250. As a result, even if the heat insulating material 62 for heat shielding is arranged inside the exhaust duct 6, for example, the heat insulating material 62 will be damaged by the compressed air discharged from the air bleed pipe 25 into the exhaust duct 6. It becomes difficult to cause negative effects such as

Further, according to the exhaust system 10 according to the several embodiments described above, the bleed pipe 25 does not protrude into the exhaust passage 61 of the exhaust duct 6, so that the bleed pipe 25 does not protrude into the exhaust passage 61 of the exhaust duct 6, unlike a conventional gas turbine. A support structure for the bleed pipe 25 that would be required if it were to protrude into the exhaust passage 61 is not required, and the configuration of the exhaust device 10 can be simplified. In addition, as in the case where the bleed pipe 25 protrudes into the exhaust passage 61 of the exhaust duct 6, the bleed pipe 25 protruding into the exhaust duct 6 may vibrate and be damaged by the exhaust gas flowing within the exhaust duct 6. Not at all.

When the bleed pipe 25 protrudes into the exhaust passage 61 of the exhaust duct 6 as in a conventional gas turbine, the bleed pipe 25 is A member such as a perforated pipe may be disposed at the downstream end to suppress the flow velocity of the compressed air discharged. In such a case, if the portion including the member that protrudes into the exhaust passage 61 becomes long in the axial direction, it becomes difficult to suppress the length of the exhaust duct 6 in the axial direction.
On the other hand, according to the exhaust device 10 according to the several embodiments described above, the bleed pipe 25 does not protrude into the exhaust passage 61 of the exhaust duct 6, so the axial length of the exhaust duct 6 can be easily suppressed. Become.

The gas turbine 1 according to some embodiments includes a compressor 3 that generates compressed air, a combustor 4 that generates combustion gas, a turbine 5 that is rotationally driven by the combustion gas generated in the combustor 4, and the above-mentioned The exhaust device 10 according to some embodiments is provided.
Thereby, the same effects as those described above are achieved.

As described above, for example, in the examples shown in FIGS. 4, 5, 8, and 9, the gradually increasing portions 250 are spaced apart in the circumferential direction toward the exhaust duct side end 251. The passage cross-sectional area is formed so as to gradually increase as the distance between the inner peripheral surfaces 250b in the circumferential direction increases gradually. That is, in the examples shown in FIGS. 4, 5, 8, and 9, the gradually increasing portion 250 is larger than the axial inner dimension a of the exhaust duct 6, as shown in FIGS. The inner dimension b in the circumferential direction is larger.
Thereby, it is possible to suppress the size of the gradually increasing portion 250 from increasing in the axial direction, and therefore it is possible to suppress the exhaust duct 6 from increasing in the axial direction.

For example, in the examples shown in FIGS. 4, 5, and 7, the upstream region 25U of the bleed pipe 25 is spaced a first distance It is arranged offset in one direction Dr1, and also offset in a second direction Dr2 perpendicular to the first direction Dr1 with respect to the central axis AX of the exhaust duct 6 by a second distance X2 smaller than the radius. It's okay.
Note that, for example, when the diameter of the exhaust duct 6 increases as it goes downstream in the axial direction, the above-mentioned radius of the exhaust duct 6 is, for example, the outer peripheral portion of the exhaust duct 6 at the axial position where the exhaust duct side end 251 exists. It is the radius.

For example, in the examples shown in FIGS. 5 and 7, one of the two illustrated air bleed pipes 25 may be the medium pressure bleed air discharge pipe 25b, and the other may be the low pressure bleed air discharge pipe 25c.
Furthermore, in the examples shown in FIGS. 5 and 7, the first direction Dr1 may be a vertical direction, and the second direction Dr2 may be a horizontal direction.

A line segment that passes through the central axis C of the upstream region 25U of the bleed pipe 25 and extends in the first direction Dr1 when viewed from the axial direction of the exhaust duct 6 is defined as a first line segment L1 (see FIG. 7).
For example, in the example shown in FIG. 7, the gradually increasing portion 250 has an inner circumferential surface 250b located farther from the central axis AX of the exhaust duct 6 than the first line segment L1 when viewed from the axial direction of the exhaust duct 6. It is preferable to extend parallel to one direction Dr1.

If separation of the flow of compressed air from the inner circumferential surfaces 250a and 250b of the gradually increasing portion 250 occurs in the gradually increasing portion 250, there is a risk that the flow velocity of the compressed air discharged from the air bleed pipe 25 into the exhaust duct 6 will be insufficiently suppressed. There is.
In the example shown in FIG. 7, the flow of compressed air separates from the inner circumferential surface 250b, which is located farther from the central axis AX of the exhaust duct 6 than the first line segment L1 when viewed from the axial direction of the exhaust duct 6. Therefore, the flow velocity of the compressed air discharged from the air bleed pipe 25 into the exhaust duct 6 can be effectively suppressed.

For example, as shown in FIGS. 8, 9, and 10, the gradually increasing portion 250 may include a rectifying plate 260 that is disposed inside the gradually increasing portion 250 and rectifies the flow of compressed air.
As described above, when separation of the compressed air flow from the inner circumferential surfaces 250a and 250b of the gradually increasing part 250 occurs in the gradually increasing part 250, the flow velocity of the compressed air discharged from the bleed pipe 25 into the exhaust duct 6 is suppressed. There is a risk that it will be insufficient.
For example, according to the configurations shown in FIGS. 8, 9, and 10, the flow of compressed air from the inner circumferential surfaces 250a, 250b of the gradually increasing portion 250 is rectified by the rectifying plate 260. Since separation of the air can be suppressed, the flow velocity of compressed air discharged from the bleed pipe 25 into the exhaust duct 6 can be effectively suppressed.

The baffle plate 260 may include a first baffle plate 261 that extends in the circumferential direction and the radial direction of the exhaust duct 6 when viewed from the axial direction of the exhaust duct 6, for example, as shown in FIG.
According to the first rectifier plate 261 shown in FIG. 8, it is possible to suppress the flow of compressed air from separating in the axial direction from the inner circumferential surface 250a of the gradually increasing portion 250, so that it is discharged from the bleed pipe 25 into the exhaust duct 6. The flow velocity of compressed air can be effectively suppressed.
Note that, as shown in FIG. 8, only one first rectifying plate 261 may be arranged, or two or more first rectifying plates 261 may be arranged spaced apart from each other in the axial direction.

The baffle plate 260 includes a second baffle plate 262 that extends in the circumferential direction and the radial direction of the exhaust duct 6 when viewed from the axial direction of the exhaust duct 6, as shown in FIGS. 9 and 10, for example. You can stay there.
According to the second baffle plate 262 shown in FIGS. 9 and 10, it is possible to suppress the flow of compressed air from separating in the circumferential direction from the inner circumferential surface 250b of the gradually increasing portion 250. The flow velocity of compressed air discharged into the air can be effectively suppressed.
In addition, as shown in FIGS. 9 and 10, the second current plate 262 may be arranged in two pieces spaced apart from each other in the circumferential direction, only one plate may be arranged, or in three pieces spaced apart from each other in the circumferential direction. More than one may be placed.

Further, the exhaust device 10 according to some embodiments may include both the first current plate 261 and the second current plate 262.

In the exhaust device 10 according to some embodiments, for example, as shown in FIG. 3, a suppressing member 27 is provided at the exhaust duct side end 251, through which compressed air can pass, and which suppresses the passage speed of the compressed air. You may be prepared.
The suppressing member 27 may be, for example, a perforated plate in which a plurality of through holes are formed, or may be a porous member. Further, the suppressing member 27 may be, for example, a slit plate in which at least one slit is formed, a net member, or a louver.
As a result, the flow velocity of the compressed air discharged from the air bleed pipe 25 into the exhaust duct 6 is further reduced by the suppressing member 27. Therefore, even if the heat insulating material 62 for heat shielding is arranged inside the exhaust duct 6, for example, the heat insulating material 62 may be damaged by the compressed air discharged from the bleed pipe 25 into the exhaust duct 6. It becomes even more difficult to cause negative effects.

The exhaust device 10 according to some embodiments may include a heat insulating member 63 disposed on the inner circumference of the gradually increasing portion 250, as shown in FIG. 11, for example.
As a result, even if the flow rate of compressed air discharged from the bleed pipe 25 into the exhaust duct 6 is small, the gradually increasing portion 250 is less likely to be affected by the heat of the exhaust gas.

The present disclosure is not limited to the embodiments described above, and also includes forms in which modifications are added to the embodiments described above, and forms in which these forms are appropriately combined.

The contents described in each of the above embodiments can be understood as follows, for example.
(1) The exhaust system 10 for the gas turbine 1 according to at least one embodiment of the present disclosure includes an annular exhaust duct 6 connected to the downstream side of the turbine 5 and into which combustion gas that rotationally drives the turbine 5 is guided, and a compressed A bleed pipe 25 is provided for guiding a part of the compressed air bleed from the machine 3 to the exhaust duct 6. The air bleed pipe 25 has a gradually increasing portion 250 in which the cross-sectional area of the flow passage gradually increases along the flow direction of the compressed air toward the downstream end in the flow direction (exhaust duct side end 251). The downstream end (exhaust duct side end 251) does not protrude into the exhaust passage 61 of the exhaust duct 6.

According to the configuration (1) above, the downstream end (exhaust duct side end 251) of the air bleed pipe 25 does not protrude into the exhaust passage 61 of the exhaust duct 6, so that the exhaust gas flowing inside the exhaust duct 6 is It becomes difficult to disturb the flow, and the influence on the flow of exhaust gas in the exhaust duct 6 can be suppressed. Further, according to the configuration (1) above, the flow velocity of the compressed air discharged from the air bleed pipe 25 into the exhaust duct 6 decreases in the gradually increasing portion 250. As a result, even if the heat insulating material 62 for heat shielding is arranged inside the exhaust duct 6, for example, the heat insulating material 62 will be damaged by the compressed air discharged from the air bleed pipe 25 into the exhaust duct 6. It becomes difficult to cause negative effects such as

(2) In some embodiments, in the configuration of (1) above, the gradually increasing portion 250 has an inner dimension b in the circumferential direction of the exhaust duct 6 that is larger than an inner dimension a in the axial direction of the exhaust duct 6. good.

According to the configuration (2) above, it is possible to suppress the size of the gradually increasing portion 250 from increasing in the axial direction. Thereby, it is possible to suppress the length of the exhaust duct 6 in the axial direction from increasing.

(3) In some embodiments, in the configuration of (2) above, the bleed pipe 25 may have an upstream region 25U that extends in the axial direction on the upstream side of the gradually increasing portion 250 in the flow direction. The upstream region 25U is arranged offset in a first direction Dr1 with respect to the central axis AX of the exhaust duct 6 by a first distance X1 larger than the radius of the exhaust duct 6, and a second distance X1 smaller than the radius The exhaust duct 6 may be offset by a distance X2 from the central axis AX of the exhaust duct 6 in a second direction Dr2 perpendicular to the first direction Dr1. A line segment passing through the central axis C of the upstream region 25U and extending in the first direction Dr1 when viewed from the axial direction of the exhaust duct 6 is referred to as a first line segment L1. The gradually increasing portion 250 has an inner circumferential surface 250b located further from the central axis AX of the exhaust duct 6 than the first line segment L1 when viewed from the axial direction of the exhaust duct 6 and extends parallel to the first direction Dr1. good.

If separation of the flow of compressed air from the inner circumferential surfaces 250a and 250b of the gradually increasing portion 250 occurs in the gradually increasing portion 250, there is a risk that the flow velocity of the compressed air discharged from the air bleed pipe 25 into the exhaust duct 6 will be insufficiently suppressed. There is.
According to the configuration (3) above, compressed air flows from the inner peripheral surface 250b located further from the central axis AX of the exhaust duct 6 than the first line segment L1 when viewed from the axial direction of the exhaust duct 6. Since it becomes difficult to separate, the flow velocity of the compressed air discharged from the bleed pipe 25 into the exhaust duct 6 can be effectively suppressed.

(4) In some embodiments, in any of the configurations (1) to (3) above, the gradually increasing part 250 is arranged inside the gradually increasing part 250, and includes a rectifying plate for rectifying the flow of compressed air. It is preferable to have 260.

As described above, when separation of the compressed air flow from the inner circumferential surfaces 250a and 250b of the gradually increasing part 250 occurs in the gradually increasing part 250, the flow velocity of the compressed air discharged from the bleed pipe 25 into the exhaust duct 6 is suppressed. There is a risk that it will be insufficient.
According to the configuration (4) above, separation of the compressed air flow from the inner circumferential surfaces 250a, 250b of the gradually increasing portion 250 can be suppressed by rectifying the flow of compressed air in the gradually increasing portion 250 with the rectifying plate 260. The flow velocity of compressed air discharged from the air bleed pipe 25 into the exhaust duct 6 can be effectively suppressed.

(5) In some embodiments, in the configuration of (4) above, the current plate 260 includes a first straightening plate 260 extending in the circumferential direction and the radial direction of the exhaust duct 6 when viewed from the axial direction of the exhaust duct 6. A current plate 261 may also be included.

According to the configuration (5) above, it is possible to suppress the flow of compressed air from separating in the axial direction from the inner circumferential surface 250a of the gradually increasing portion 250, so that the flow of compressed air discharged from the air bleed pipe 25 into the exhaust duct 6 can be Flow velocity can be effectively suppressed.

(6) In some embodiments, in the configuration of (4) or (5) above, the current plate 260 extends in the circumferential direction and radial direction of the exhaust duct 6 when viewed from the axial direction of the exhaust duct 6. The second current plate 262 may also be included.

According to the configuration (6) above, it is possible to suppress the flow of compressed air from separating in the circumferential direction from the inner circumferential surface 250b of the gradually increasing portion 250, so that the flow of compressed air discharged from the air bleed pipe 25 into the exhaust duct 6 can be Flow velocity can be effectively suppressed.

(7) In some embodiments, in any of the configurations (1) to (6) above, it is arranged at the downstream end (exhaust duct side end 251) and allows compressed air to pass through. A suppressing member 27 that suppresses the passage speed of compressed air may be provided.

According to the configuration (7) above, the flow velocity of the compressed air discharged from the bleed pipe 25 into the exhaust duct 6 is further reduced by the suppressing member 27. As a result, even if the heat insulating material 62 for heat shielding is arranged inside the exhaust duct 6, for example, the heat insulating material 62 will be damaged by the compressed air discharged from the air bleed pipe 25 into the exhaust duct 6. It becomes even more difficult to cause negative effects such as

(8) In some embodiments, the structure of any one of the above (1) to (7) may include a heat insulating member 63 disposed on the inner peripheral portion of the gradually increasing portion 250.

According to the configuration (8) above, even if the flow rate of compressed air discharged from the bleed pipe 25 into the exhaust duct 6 is small, the gradually increasing portion 250 is less likely to be affected by the heat of the exhaust gas.

(9) The gas turbine 1 according to at least one embodiment of the present disclosure includes a compressor 3 that generates compressed air, a combustor 4 that generates combustion gas, and is rotationally driven by the combustion gas generated in the combustor 4. It includes a turbine 5 and an exhaust system 10 for the gas turbine 1 having any of the configurations (1) to (8) above.

According to the configuration (9) above, the downstream end (exhaust duct side end 251) of the air bleed pipe 25 does not protrude into the exhaust passage 61 of the exhaust duct 6, so that the exhaust gas flowing inside the exhaust duct 6 is It becomes difficult to disturb the flow, and the influence on the flow of exhaust gas in the exhaust duct 6 can be suppressed. Further, according to the configuration (9) above, the flow velocity of the compressed air discharged from the bleed pipe 25 into the exhaust duct 6 decreases in the gradually increasing portion 250. As a result, even if the heat insulating material 62 for heat shielding is arranged inside the exhaust duct 6, for example, the heat insulating material 62 will be damaged by the compressed air discharged from the air bleed pipe 25 into the exhaust duct 6. It becomes difficult to cause negative effects such as

1 Gas turbine 3 Compressor 4 Combustor 5 Turbine 6 Exhaust duct 10 Exhaust device 25 Bleed pipe 25U Upstream region 27 Suppressing member 61 Exhaust passage 62 Heat insulating material 63 Heat insulating member 250 Gradually increasing portions 250a, 250b Inner peripheral surface 251 Exhaust duct side end Part 260 Current plate 261 First current plate 262 Second current plate

Claims (9)

an annular exhaust duct connected to the downstream side of the turbine, through which combustion gas that rotates the turbine is guided;
an air bleed pipe for guiding a part of the compressed air extracted from the compressor to the exhaust duct;
Equipped with
The air bleed pipe has a gradually increasing portion in which the cross-sectional area of the flow passage gradually increases as it goes toward the downstream end in the flow direction along the flow direction of the compressed air,
the downstream end does not protrude into the exhaust passage of the exhaust duct;
Gas turbine exhaust system. The gradually increasing portion has an inner dimension in the circumferential direction of the exhaust duct that is larger than an inner dimension in the axial direction of the exhaust duct.
The exhaust system for a gas turbine according to claim 1. The bleed pipe has an upstream region extending in the axial direction upstream of the gradually increasing portion in the flow direction,
The upstream region is arranged to be offset in a first direction with respect to the central axis of the exhaust duct by a first distance that is larger than the radius of the exhaust duct, and the upstream region is offset from the central axis of the exhaust duct by a second distance that is smaller than the radius. arranged offset in a second direction perpendicular to the first direction with respect to the central axis of the duct,
When a line segment passing through the central axis of the upstream region and extending in the first direction is defined as a first line segment when viewed from the axial direction of the exhaust duct, the gradually increasing portion is arranged along the axis of the exhaust duct. an inner circumferential surface located further from the central axis of the exhaust duct than the first line segment when viewed from the direction extends parallel to the first direction;
The exhaust system for a gas turbine according to claim 2. The gradually increasing part has a rectifying plate disposed inside the gradually increasing part to straighten the flow of the compressed air.
An exhaust system for a gas turbine according to any one of claims 1 to 3. The current plate includes a first current plate that extends in the circumferential direction and the radial direction of the exhaust duct when viewed from the axial direction of the exhaust duct.
The exhaust system for a gas turbine according to claim 4. The current plate includes a second current plate that extends in the circumferential direction and the radial direction of the exhaust duct when viewed from the axial direction of the exhaust duct.
The exhaust system for a gas turbine according to claim 4 or 5. a suppressing member disposed at the downstream end, through which the compressed air can pass, and suppressing the passage speed of the compressed air;
The exhaust system for a gas turbine according to any one of claims 1 to 6, comprising: a heat insulating member disposed on the inner periphery of the gradually increasing part;
The exhaust system for a gas turbine according to any one of claims 1 to 7, comprising: a compressor that generates compressed air;
a combustor that generates combustion gas;
a turbine rotationally driven by combustion gas generated in the combustor;
The exhaust system for a gas turbine according to any one of claims 1 to 8,
Equipped with
gas turbine.

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