JP2010001764A - Divided ring cooling structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a divided ring cooling structure of a gas turbine capable of minimizing the use amount of cooling air and of further increasing the cooling efficiency and cooling capacity of a divided ring. <P>SOLUTION: This divided ring cooling structure cools the divided ring of a gas turbine which comprises a plurality of divided bodies 11 arranged in the circumferential direction and formed in an annular shape and which is disposed in a cabin in such a manner that the inner peripheral surface thereof keeps a specified distance from the end of the moving blade 5 thereof. In the structure, a convection cooling flow passage 21 is formed to flow cooling air after impingement cooling along the upstream side end of the divided body 11 in the combustion gas flow direction, a restricted section 24 is formed at the outlet 23 of the convection cooling flow passage 21, and an air outlet hole 26 communicating with an impingement cooling space is formed at the side ends 14, 15 of the divided body 11 and the downstream side end 25 thereof in the combustion gas flow direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a split ring cooling structure for a gas turbine.

Conventionally, in a gas turbine used for power generation or the like, high-temperature and high-pressure combustion gas passes through a turbine portion, so cooling of a split ring or the like is important in order to continue stable operation.
As a conventional technique related to cooling of the split ring, there is disclosed a technique that suppresses the temperature of the split ring to prevent defects due to high-temperature oxidation and reduces distortion of the split ring due to thermal deformation. (For example, see Patent Document 1)

Moreover, about the cooling hole of the division | segmentation ring edge part, the cooling hole structure of the division | segmentation ring which reduces the location of a bending part and improves workability | operativity at the time of casting is proposed. (For example, see Patent Document 2)
In addition, in order to improve the cooling efficiency of the split ring, the split is provided with a plurality of cavities that are divided in the axial direction by a pressure partition plate extending in the circumferential direction between the split ring and the impingement cooling plate and adjusted to different pressures, respectively. An annulus cooling structure is disclosed. (For example, see Patent Document 3)
JP 2004-1000068 A Japanese Patent Laid-Open No. 11-22411 Japanese Patent Laid-Open No. 11-247621

By the way, in the division | segmentation ring cooling structure of patent document 2 and 3, the cooling air after impingement cooling was utilized, and convection cooling was performed only about a part of division | segmentation ring ends.
In addition, the split ring cooling structure of Patent Document 1 provides cooling passages on four sides of the split ring to discharge the cooling air after impingement cooling, so that the number of drilling operations increases, Due to the length of the cooling channel, the cooling air temperature at the outlet is raised, and there is a problem that sufficient end cooling cannot be performed. In particular, at the upstream end portion in the combustion gas flow direction where the heat load is large, the impingement cooling cannot be performed because there is a connecting portion, and the problem of insufficient cooling becomes more prominent.

Although it is conceivable to increase the cooling air amount to improve the cooling capacity of the split ring or the like, the increased amount of the cooling air amount lowers the temperature of the combustion gas passing through the turbine section. Therefore, even if the temperature of the combustion gas supplied from the combustor is set high, if the combustion gas temperature is lowered by using a large amount of cooling air, improvement in the operation efficiency of the gas turbine is hindered.
In recent years, the temperature of the combustion gas supplied to the turbine section tends to increase with the aim of improving the efficiency of gas turbines, so the thermal environment of the split ring becomes increasingly severe. There is concern about the shortage. Therefore, in order to continue the stable operation of the gas turbine, it is desired to eliminate the insufficient cooling of the split ring and further improve the cooling efficiency and cooling capacity of the split ring and the like.

From such a background, in the split ring cooling structure of a gas turbine, it is desired to minimize the amount of cooling air used and further improve the cooling efficiency and cooling capacity of the split ring.
The present invention has been made in view of the above circumstances, and its object is to minimize the amount of cooling air used and to further improve the cooling efficiency and cooling capacity of the split ring. An object of the present invention is to provide a split ring cooling structure for a gas turbine.

In order to solve the above problems, the present invention employs the following means.
The first aspect of the divided ring cooling structure according to the present invention is composed of a plurality of annularly arranged divided bodies arranged in the circumferential direction, and the inner circumferential surface keeps a certain distance from the tip of the moving blade. In the split ring cooling structure for cooling the split ring of the gas turbine disposed in the convection cooling channel, a convection cooling flow path for flowing cooling air after impingement cooling is formed along the upstream end of the split body in the combustion gas flow direction. In addition, a throttle portion is provided at the outlet of the convection cooling flow path, and an air outflow hole communicating with the impingement cooling space is provided at the side end portion of the divided body and the downstream end portion in the combustion gas flow direction. Is.

According to the first aspect of the present invention described above, the convection cooling flow path for flowing the cooling air after impingement cooling is formed along the upstream end portion in the combustion gas flow direction of the divided body. A throttle part is provided at the outlet, and an air outlet hole communicating with the impingement cooling space is provided at the side end of the divided body and the downstream end in the combustion gas flow direction. The amount of cooling air defined by the above flows through the convection cooling flow path, and the upstream end portion in the combustion gas flow direction of the divided body with severe heat load can be efficiently cooled. Such a convection cooling channel can reduce the number of processing compared to a structure in which a large number of cooling holes are formed.
Further, the side end portion of the divided body and the downstream end portion in the combustion gas flow direction can also be cooled by the cooling air after impingement cooling flowing out from the air outflow hole communicating with the impingement cooling space.

  The second aspect of the split ring cooling structure according to the present invention is composed of a plurality of annularly arranged divided bodies arranged in the circumferential direction, and the inner peripheral surface is kept at a certain distance from the tip of the moving blade. In the split ring cooling structure for cooling the split ring of the gas turbine disposed in the convection cooling channel, a convection cooling flow path for flowing cooling air after impingement cooling is formed along the upstream end of the split body in the combustion gas flow direction. In addition, an air outflow hole is provided at the end of the convection cooling channel, and an air outflow hole communicating with the impingement cooling space is provided at the side end of the divided body and the downstream end of the combustion gas flow direction. To do.

  According to the second aspect of the present invention described above, the convection cooling flow path for flowing the cooling air after impingement cooling is formed along the upstream end portion in the combustion gas flow direction of the divided body. Since the air outflow hole is provided at the end, and the air outflow hole communicating with the impingement cooling space is provided at the side end of the divided body and the downstream end of the combustion gas flow direction, the same action as the first aspect described above In addition, since the cooling air after the convection cooling is discharged into the combustion gas flow from the air outflow hole provided at the end of the convection cooling flow path, the cooling of the end portion on the leading edge side is enhanced.

  The third aspect of the split ring cooling structure according to the present invention is composed of a plurality of annularly arranged divided bodies arranged in the circumferential direction, and the inner peripheral surface is kept at a certain distance from the tip of the moving blade. In the split ring cooling structure for cooling the split ring of the gas turbine disposed in the convection cooling channel, a convection cooling flow path for flowing cooling air after impingement cooling is formed along the upstream end of the split body in the combustion gas flow direction. A side flow path communicating with the convection cooling flow path is formed at a side end of the divided body, an air outflow hole communicating with the side flow path is provided at a side end of the divided body, and a combustion gas flow An air outflow hole communicating with the impingement cooling space is provided at the downstream end in the direction.

  According to the third aspect of the present invention described above, the convection cooling flow path for flowing the cooling air after impingement cooling is formed along the upstream end portion in the combustion gas flow direction of the divided body, and the side end portion of the divided body A side flow passage that communicates with the convection cooling flow passage, an air outflow hole that communicates with the side flow passage is provided at the side end of the divided body, and an impingement cooling space at the downstream end in the combustion gas flow direction. Since the air outflow hole communicating with the air is provided, a side channel communicating with the convection cooling channel is formed at the side end of the divided body, and the air communicating with the side channel is formed at the side end of the divided body. Since the outflow hole is provided, the cooling air can be reused, and the amount of cooling air can be further reduced.

  In the above invention, the convection cooling flow path introduces cooling air from an inlet opening to the impingement cooling space on the upstream side in the rotor blade rotation direction of the divided body, and on the downstream side in the rotor blade rotation direction of the divided body. It is preferable to let it flow out from the outlet opening at the side end, so that the flow of cooling air flowing out from the outlet to the combustion gas flow path through the convection cooling flow path becomes smooth.

  In the above invention, the air outflow holes provided at the side ends of the divided bodies and the downstream end in the combustion gas flow direction are preferably inclined from the combustion gas flow direction, thereby reducing the amount of cooling air. Is possible.

  According to the present invention described above, it is possible to provide a split ring cooling structure for a gas turbine in which the amount of cooling air used is minimized and the cooling efficiency and cooling capacity of the split ring are further improved. Therefore, the combustion gas temperature of the gas turbine that is lowered by the cooling air can be minimized, and the reliability and operating efficiency of the gas turbine can be improved.

Hereinafter, an embodiment of a split ring cooling structure according to the present invention will be described with reference to the drawings.
As shown in FIG. 12, the gas turbine 1 includes a compressor (compressor) 2 that compresses combustion air, and injects and burns fuel into the high-pressure air sent from the compressor 2 to perform high-temperature combustion. The main elements are a combustion section (combustor) 3 that generates gas and a turbine section (turbine) 4 that is located on the downstream side of the combustion section 3 and is driven by the combustion gas exiting the combustion section 3. is there.

FIG. 2 shows a cross-sectional view of the main part of the split ring 10 as the split ring cooling structure of the gas turbine 1 according to the present embodiment. The split ring 10 is made of, for example, a nickel alloy.
The split ring 10 includes a plurality of ring-shaped split bodies 11 that are arranged in the circumferential direction, and the inner peripheral surface 11a is kept at a constant distance from the tip 5a of the rotor blade 5 so that the vehicle interior of the gas turbine 1 is kept. It is a structural member of the turbine part 4 arrange | positioned. In addition, the code | symbol 6 in a figure is a stationary blade of the turbine part 4. FIG.

  In the gas turbine 1 described above, the blade length L (the blade leading edge 5b and the blade trailing edge) set in the region where the split ring 10 and the blade 5 are close to each other, that is, the tip 5a of the blade 5 shown in FIG. In the region between 5c and 5c), since the high-temperature combustion gas flows through the gap between the split ring 10 and the rotor blade tip 5a, it is necessary to cool the split body 11 in particular.

  The divided body 11 is attached to the heat shield ring 30 by a hook 12 provided on the upstream side of the high-temperature gas and a hook 13 provided on the downstream side. For example, as shown in FIG. 1, the divided body 11 includes hooks 12 and 13 provided on the upstream side and the downstream side in the combustion gas flow direction, and the upstream side in the rotor blade rotation direction substantially orthogonal to the combustion gas flow direction. Further, an impingement cooling surface (hereinafter referred to as “cooling surface”) 16 surrounded by side end portions 14 and 15 provided on the downstream side is formed. The cooling surface 16 is on the back surface (outer peripheral surface) side when viewed from the inner peripheral surface 11a of the divided body 11 where the tip 5a of the rotor blade 5 rotates at a predetermined distance, and a large number of dimples 17 are formed to increase the surface area. Has been.

An impingement plate (hereinafter referred to as “shielding plate”) 19 is installed above the cooling surface 16 so as to form an impingement cooling space (hereinafter referred to as “cooling space”) 18. . A large number of small holes 20 through which cooling air for impingement cooling is passed are formed in the shielding plate 19.
Above the shielding plate 19, a cooling air receiving space 33 is formed which introduces cooling air for impingement cooling which is defined by the heat shielding ring 30 and is supplied through the cooling air supply flow path 32. The cooling air supplied into the cooling air receiving space 33 flows out from the small hole 20 in a state where the whole is equalized to substantially the same pressure, and impingement cools the cooling surface 16.

FIG. 3 is a plan view showing the first embodiment of the divided body 11 of the divided ring 10 shown in FIG. 4 is a cross-sectional view taken along the line AA in FIG. 3, and FIG. 5 is a cross-sectional view taken along the line BB in FIG.
In the divided body 11 of the present embodiment, a convection cooling flow path 21 is provided along the upstream end portion in the combustion gas flow direction. The convection cooling flow path 21 is a flow path for flowing the cooling air after impingement cooling in the direction of the broken line arrow Ca in the figure, and an inlet 22 that opens into the impingement cooling space on the upstream side in the moving blade rotation direction of the divided body 11. Then, cooling air is introduced from the outlet 23 and flows out from an outlet 23 that opens at the side end 14 of the divided body 11 on the downstream side in the rotor blade rotation direction.
A constricted portion 24 having a narrow channel cross-sectional area is provided at the outlet 23 of the convection cooling channel 21 formed in the divided body 11.

That is, the convection cooling channel 21 is a hollow portion formed inside the hook 12 at the upstream end portion of the divided body 11 in the combustion gas flow direction, and the convection cooling channel 21 has an inlet 22 in the cooling space 18. The outlet 23 opens to the side end portion 14 on the downstream side in the moving blade rotation direction. In this case, the outlet 23 coincides with the outlet of the throttle section 24 provided in the convection cooling channel 21.
With such a convection cooling flow path 21, the flow of cooling air flowing out from the outlet 23 to the combustion gas flow path between the stationary blade 4 and the moving blade 5 through the convection cooling flow path 21 becomes the flow of combustion gas. Smooth along.

  A plurality of air outflow holes 26 communicating with the cooling space 18 are provided at a predetermined pitch in the side end portions 14 and 15 of the divided body 11 and the downstream end portion 25 of the divided body 11 which is downstream in the combustion gas flow direction. It has been. In the following description, when distinguishing by the position where the air outflow hole 26 is installed, the passage (flow path) provided in the side end portion 14 is the air outflow hole 26A, and the passage provided in the side end portion 15 is the air outflow hole 26B, The passage provided in the downstream end portion 25 is referred to as an air outflow hole 26R, and the symbol H in the figure is the passage outlet opening.

Now, in the first embodiment shown in FIG. 3, the air outflow holes 26A, 26B provided in the side end portions 14, 15 are both inclined from the rotating blade rotation direction and the combustion gas flow direction. That is, the air outflow hole 26A is inclined from the combustion gas flow direction to the upstream side in the rotor blade rotation direction, and the air outflow hole 26B is inclined from the combustion gas flow direction to the downstream side in the rotor blade rotation direction. Is provided.
Moreover, the air outflow hole 26R provided in the downstream end 25 is provided in parallel with the combustion gas flow direction.

According to the split ring cooling structure described above, impingement cooling of the split ring 11 and the split ring 10 having the split body 11 as components is caused by the cooling air that has passed through the small holes 20 of the shielding plate 19 colliding with the cooling surface 16. Is done. A part of the cooling air thus used for impingement cooling flows into the convection cooling flow path 21 from the inlet 22 that opens to the cooling space 18. The cooling air flows through the convection cooling flow path 21 and flows out from the outlet 23. In this process, the upstream end region of the divided body 11 is cooled.
The rest of the cooling air used for impingement cooling, that is, the cooling air other than that used to cool the upstream end region after flowing into the convection cooling flow path 21 is the side ends 14, 15 and Since it flows out from the air outflow hole 26 provided in the downstream end 25, the side ends 14 and 15 and the downstream end 25 of the divided body 11 can also be cooled.

  In the conventional split ring cooling structure, impingement cooling is performed on the convection cooling channel 21 provided along the upstream end of the end region on the upstream side in the combustion gas flow direction of the split body 11 where there is a concern about insufficient cooling. Since subsequent cooling air flows and cools, efficient and reliable cooling can be performed. At this time, since the throttle part 24 is provided at the outlet 23 of the convection cooling channel 21, the amount of cooling air distributed to the upstream end region and the other end regions can be defined. That is, in the cooling air after impingement cooling, the amount of cooling air defined by the throttle portion 24 flows through the convection cooling flow path 21 and can efficiently cool the upstream end of the divided body 11 in the combustion gas flow direction. .

Such a convection cooling channel 21 has an advantage that the number of processing can be reduced as compared with the conventional structure in which a large number of cooling holes are formed. Further, in the region where the impingement cooling cannot be performed due to the presence of the hook 12, the temperature of the cooling air passing through the long cooling hole and flowing out from the outlet is considerably high. In the structure, it is difficult to secure the cooling capacity unless the amount of cooling air is increased. However, since the convection cooling channel 21 described above can be cooled reliably and efficiently, the amount of cooling air can be minimized. In addition, as shown in FIG. 6, the air outflow hole 26B on the side end 15 side serves to cool the ship wrap structure formed between the adjacent divided bodies 11 in addition to cooling the side end itself. Also fulfills.
In addition, the air outflow holes 26 provided in the side end portions 14 and 15 and the downstream end portion 25 of the divided body 11 are inclined from the direction of combustion gas flow, including the modifications described later, thereby cooling air. Therefore, the amount of cooling air can be reduced.

FIG. 6 is a plan view showing a second embodiment of the divided body 11 of the divided ring 10 shown in FIG.
The divided body 11A of the present embodiment differs from the first embodiment described above in that a plurality of air outflow holes 26C are provided on the side end portion 14 side of the convection cooling passage 21. The air outflow hole 26C is connected to the convection cooling passage 21 on the upstream side and is opened to the combustion gas flow on the downstream side, thereby cooling the vicinity of the end portion of the side end portion 14 on the upstream side in the combustion gas flow direction. is doing.
A plurality of air outflow holes 26C are arranged from the upstream side toward the downstream side of the side end of the combustion gas flow within a range not interfering with the impingement cooling surface 16, and FIG. 7 relates to the arrangement of the air outflow holes 26C. An example is shown (DD view of FIG. 6). Further, since the flow rate of the cooling air blown out from the air outflow hole 26C can be adjusted by changing the diameter of the air outflow hole 26C, the air outflow hole 26C also serves as a throttle.

  According to this embodiment, the convection cooling of the front edge side end portion is performed, and the upstream side of the side end portion 14 that is concerned about insufficient cooling in the conventional structure can be cooled by the cooling air after the convection cooling. Therefore, the amount of cooling air can be reduced by reusing the cooling air.

FIG. 8 is a plan view showing a third embodiment of the divided body 11 of the divided ring 10 shown in FIG.
The divided body 11B of this embodiment differs from the first embodiment described above in the following points. That is, the convection cooling passage 21 includes an inlet 22 for introducing cooling air from the impingement cooling space (cooling surface 16) in the vicinity of the center thereof. On the downstream side of the convection cooling passage 21, side cooling passages 27 </ b> A and 27 </ b> B arranged at the side end portions 14 and 15 of the divided body 11 </ b> B communicate with each other.
The side cooling passages 27A and 27B are provided with air outflow holes 26D and 26E so as to communicate with the side end portions 14 and 15, respectively.
In addition, the air outflow holes 26D and 27E communicating with the side end portions 14 and 15 are preferably arranged such that the opening H of the end surfaces 14a and 15a is within the range of the blade length L of the moving blade 5 shown in FIG. .

  As described above, when the side cooling passages 27A and 27B communicating with the convection cooling passage 21 are provided and the air outflow holes 26D and 26E opened in the side end portions 14 and 15 are provided, the use of the cooling air is performed. Since it can be rotated, a reduction in the amount of cooling air can be expected. Further, by arranging the opening H of the air outflow holes 26D and 27E within the range of the blade length L of the rotor blade 5, the split ring 10 can perform effective cooling particularly in a region where the heat load is severe. it can.

By the way, about the air outflow hole 26, it is not limited to each embodiment mentioned above, For example, the modification as demonstrated below based on FIG.10 and FIG.11 is possible. In addition, the same code | symbol is attached | subjected to the part similar to each embodiment mentioned above, and the detailed description is abbreviate | omitted.
In the first modification shown in FIG. 10 and the second modification shown in FIG. 11, the air outflow hole 26B at the side end 15 is eliminated, and the air outflow hole 26R ′ provided at the downstream end 25 is inclined. Yes. In these cases, as shown in FIG. 9 (C-C cross-sectional view of FIG. 3), for example, the cooling of the side end portion 15 employs a ship wrap structure with the adjacent divided body 11, so that it is adjacent. Cooling air flowing out from the air outflow hole 26A of the divided body 11 can be used.

Further, when the first modification and the second modification are compared, the inclination angles of the air outflow holes 26 provided in the side end portion 14 and the downstream end portion 25 are different. That is, in the first modification, the air outflow hole 26A and the air outflow hole 26R ′ are inclined at different angles, but in the second modification, the air outflow hole 26A ′ and the air outflow hole 26R ″ are formed. The angle of inclination is the same.
As a result, in the first modification, the flow of the cooling air flowing out from the air outflow hole 26A close to the downstream end 25 and the air outflow hole 26R ′ close to the side end 14 interfere with each other, and the flow is disturbed. On the other hand, this problem is solved in the second modification.

As described above, according to the above-described split ring cooling structure of the present invention, the amount of cooling air used is minimized, and the cooling efficiency and cooling capacity of the split body 11 and the split ring 10 including the split body 11 are increased. This can be further improved.
In addition, this invention is not limited to embodiment mentioned above, In the range which does not deviate from the summary of this invention, it can change suitably.

It is a perspective view of an important section showing one embodiment of a division ring cooling structure concerning the present invention. It is sectional drawing of the principal part which shows the condition where the split ring shown in FIG. 1 was assembled | attached to the gas turbine. It is the top view seen from the impingement cooling surface side about 1st Embodiment which concerns on the division body shown in FIG. It is AA sectional drawing of FIG. It is a BB arrow line view of FIG. It is the top view seen from the impingement cooling surface side about 2nd Embodiment which concerns on the division body shown in FIG. It is the DD arrow line view of FIG. It is the top view seen from the impingement cooling surface side about 3rd Embodiment which concerns on the division body shown in FIG. It is CC sectional drawing of FIG. It is a top view which shows the 1st modification which concerns on the division body of FIG. It is a top view which shows the 2nd modification which concerns on the division body of FIG. It is a partial section perspective view showing an outline of a gas turbine.

Explanation of symbols

1 Gas Turbine 10 Split Ring 11, 11A, 11B Split Body 12, 13 Hook 14, 15 Side End 16 Impingement Cooling Surface (Cooling Surface)
17 Dimple 18 Impingement cooling space (cooling space)
19 Impingement plate (shield plate)
20 Small hole 21 Convection cooling flow path 22 Inlet 23 Outlet 24 Restriction part 25 Downstream end part 26, 26A, 26B Air outflow hole 30 Heat shield ring 32 Cooling air supply flow path 33 Cooling air receiving space

Claims (5)

Divided to cool the ring ring of the gas turbine that is arranged in the vehicle interior so that the inner circumferential surface is kept at a certain distance from the tip of the rotor blade, and is composed of a plurality of annularly arranged divided bodies arranged in the circumferential direction In the ring cooling structure,
Forming a convection cooling flow path through which cooling air after impingement cooling flows along the upstream end portion in the combustion gas flow direction of the divided body, and providing a throttle at the outlet of the convection cooling flow path;
A split ring cooling structure characterized in that an air outflow hole communicating with the impingement cooling space is provided at a side end portion of the split body and a downstream end portion in the combustion gas flow direction. Divided to cool the ring ring of the gas turbine that is arranged in the vehicle interior so that the inner circumferential surface is kept at a certain distance from the tip of the rotor blade, and is composed of a plurality of annularly arranged divided bodies arranged in the circumferential direction In the ring cooling structure,
A convection cooling flow path for flowing cooling air after impingement cooling is formed along the upstream end portion in the combustion gas flow direction of the divided body, and an air outflow hole is provided at the end of the convection cooling flow path.
A split ring cooling structure characterized in that an air outflow hole communicating with the impingement cooling space is provided at a side end portion of the split body and a downstream end portion in the combustion gas flow direction. Divided to cool the ring ring of the gas turbine that is arranged in the vehicle interior so that the inner circumferential surface is kept at a certain distance from the tip of the rotor blade, and is composed of a plurality of annularly arranged divided bodies arranged in the circumferential direction In the ring cooling structure,
Forming a convection cooling flow path for flowing cooling air after impingement cooling along the upstream end portion in the combustion gas flow direction of the divided body;
Forming a side cooling channel communicating with the convection cooling channel at a side end of the divided body, and providing an air outflow hole communicating with the side cooling channel at a side end of the divided body;
A split ring cooling structure characterized in that an air outflow hole communicating with the impingement cooling space is provided at the downstream end portion in the combustion gas flow direction.   The convection cooling channel introduces cooling air from an inlet opening into the impingement cooling space on the upstream side in the rotor blade rotation direction of the divided body, and opens at a side end portion on the downstream side in the rotor blade rotation direction of the divided body. The split ring cooling structure according to claim 1, wherein the split ring cooling structure is caused to flow out from an outlet. The split ring cooling structure according to any one of claims 1 to 3, wherein the air outflow hole is inclined from a combustion gas flow direction.

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