JP2005069167A - Two-shaft gas turbine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a two-shaft gas turbine capable of reducing a thrust load of a low-pressure turbine rotor without the need to increase the axial dimensions. <P>SOLUTION: A two-shaft gas turbine has a high-pressure turbine 9 equipped with a high-pressure turbine rotor 8, and a low-pressure turbine 12 equipped with a low-pressure turbine rotor 11 separated from the high-pressure turbine rotor 8 by a bulkhead 16. The low-pressure turbine 12 includes a first cavity 27 formed by a first-stage turbine disk 18 of the low-pressure turbine rotor 11 and the bulkhead 16; an inner periphery side cavity 29a formed by the first-stage turbine disk 18 and a casing 20, and formed between seal parts 30A, 30B; and an introduction hole 31 for introducing a compressed air extracted from a compressor 4, for example, into the inner periphery side cavity 29a via a high-pressure air supply route 32, so that the pressure of the inner periphery side cavity 29a may become higher than the pressure of the first cavity 27. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a two-shaft gas turbine having a high-pressure turbine rotor and a low-pressure turbine rotor separated by partition walls.

  In general, a gas turbine includes a compressor, a combustor that mixes and burns compressed air and fuel from the compressor, a compressor rotor and a load (eg, a generator, a compressor, a pump, and the like) of the compressor. And a turbine with a connected turbine rotor. And the high pressure high temperature combustion gas from a combustor is introduce | transduced into a turbine, A turbine rotor is rotationally driven by this combustion gas, and a compressor and load are driven.

  At this time, the turbine rotor receives a thrust load downstream in the flow direction of the combustion gas due to a pressure difference in the flow direction of the combustion gas in the turbine (upstream pressure> downstream pressure). The compressor rotor is subjected to a thrust load on the upstream side in the flow direction of the compressed air due to a pressure difference in the flow direction of the compressed air in the compressor (upstream pressure <downstream pressure). As described above, since the turbine rotor is connected to the compressor rotor, the thrust loads are offset and reduced.

  Here, a gas turbine including a turbine rotor that is not connected to a compressor rotor, such as a compressed air storage gas turbine power generation system, is known. This gas turbine receives the thrust load generated by the pressure difference of the combustion gas described above by, for example, a thrust bearing provided on the downstream side of the turbine rotor. However, the pressure ratio may be increased in order to improve the thermal efficiency of the gas turbine. In this case, the pressure of the entire gas turbine is increased, and the thrust load is increased. As the thrust load increases, the thrust bearing increases the effective area while reducing the surface pressure (the value obtained by dividing the thrust load by the effective area) to a predetermined value or less, resulting in an increase in size and cost. In addition, due to the increase in the size of the thrust bearing, the thrust collar of the low-pressure turbine rotor increases and the peripheral speed on the outer periphery increases, so the possibility of seizure increases and the reliability of the thrust bearing decreases and bearing loss increases. As a result, there was a problem that the thermal efficiency was lowered.

  Therefore, conventionally, for example, a balance piston connected to the upstream side of the turbine rotor, a compressed air line for supplying compressed air to the gas turbine side of the balance piston, an anti-gas turbine side of the balance piston, and a downstream side of the gas turbine The structure provided with the air line which connects is proposed (for example, refer patent document 1). In this prior art, the pressure on the gas turbine side of the balance piston is adjusted to be higher than the pressure on the anti-gas turbine side, and a thrust load is applied to the anti-gas turbine side acting on the balance piston, so that the thrust of the turbine rotor is increased. The load is reduced.

JP 2001-140604 A

  Generally, a two-shaft gas turbine includes a high-pressure turbine having a high-pressure turbine rotor connected to a compressor, and a low-pressure turbine having a low-pressure turbine rotor separated from the high-pressure turbine rotor by a partition wall and connected to a load. Have Since the high-pressure turbine rotor is connected to the compressor rotor, as described above, the thrust load is offset by the thrust load acting on the compressor rotor and decreases. The low-pressure turbine rotor receives a thrust load with a thrust bearing provided on the downstream side thereof.

  Here, when it is going to apply the said prior art to the said low pressure turbine rotor, the following subjects exist. In other words, the conventional technology has a structure in which a balance piston is connected to the upstream side of the turbine rotor. Therefore, when a balance piston is provided on the upstream side of the low-pressure turbine rotor, a two-shaft gas turbine (specifically, a low-pressure turbine) The axial dimension of the turbine rotor and related parts) increases. For this reason, there are problems such as an increase in the area of the parts to be cooled exposed to the high-temperature combustion gas and an increase in the flow rate of cooling air for cooling them.

  An object of the present invention is to provide a two-shaft gas turbine capable of reducing the thrust load of a low-pressure turbine rotor without increasing the axial dimension.

  (1) In order to achieve the above object, the present invention provides a compressor, a combustor that mixes and burns compressed air and fuel from the compressor, and combustion from the combustor that is connected to the compressor. A high-pressure turbine having a high-pressure turbine rotor that is rotationally driven by gas, and a low-pressure turbine having a low-pressure turbine rotor that is separated from the high-pressure turbine rotor by a partition wall, is connected to a load, and is rotationally driven by the combustion gas from the high-pressure turbine The low pressure turbine includes: a first space formed by an initial stage turbine disk of the low pressure turbine rotor and the partition; a final stage turbine disk of the low pressure turbine rotor; and the low pressure turbine rotor. The second space formed by the casing and the pressure in the second space is higher than the pressure in the first space. And a first pressure adjusting means for adjusting the so that.

  Generally, in a two-shaft gas turbine, a first space formed by a first stage turbine disk and a partition wall of a low pressure turbine rotor, and a second space formed by a final stage turbine disk of the low pressure turbine rotor and a casing of the low pressure turbine rotor. Has a slightly higher pressure than the gas path to prevent the combustion gas from entering from the combustion gas flow path (gas path). Therefore, corresponding to the pressure difference in the flow direction of the combustion gas (upstream pressure> downstream pressure), the pressure difference between the first space and the second space (pressure in the first space> second pressure). Space pressure). As a result, the downstream thrust load acting on the rotor blade due to the pressure difference of the combustion gas and the downstream thrust load acting on the turbine disk due to the pressure difference between the first space and the second space are added. As a result, the thrust load of the low-pressure turbine rotor was increased.

  In the present invention, the first pressure adjusting means adjusts the pressure in the second space to be higher than that in the first space. Thus, an upstream thrust load acting on the turbine disk is generated by the pressure difference between the first space and the second space (the pressure in the first space <the pressure in the second space), and the pressure of the combustion gas Since the difference cancels out the thrust load in the downstream direction acting on the rotor blade, the thrust load of the low-pressure turbine rotor can be reduced. At this time, since the first pressure adjusting means introduces high-pressure air into the second space through, for example, an introduction hole provided in the casing of the low-pressure turbine rotor, for example, a structure in which a balance piston is provided upstream of the low-pressure turbine rotor. As described above, the axial dimension of the two-shaft gas turbine (specifically, the low-pressure turbine rotor and related components) does not increase. Therefore, the thrust load of the low-pressure turbine rotor can be reduced without increasing the axial dimension.

  (2) In the above (1), preferably, the first pressure adjusting means has a seal portion that is provided in the second space and suppresses leakage of high-pressure air in the second space.

  (3) In the above (1) or (2), preferably, the first pressure adjusting means includes an introduction hole provided in the casing forming the second space, and the second hole through the introduction hole. High pressure air supply means for supplying air having a pressure higher than the pressure of the first space to the space;

  (4) In order to achieve the above object, the present invention also provides a compressor, a combustor that mixes and burns compressed air and fuel from the compressor, and the compressor connected to the combustor. A high pressure turbine having a high pressure turbine rotor that is rotationally driven by combustion gas, and a low pressure having a low pressure turbine rotor that is separated from the high pressure turbine rotor by a partition, is connected to a load, and is rotationally driven by the combustion gas from the high pressure turbine In the two-shaft gas turbine having a turbine, the low-pressure turbine includes a first space formed by a first-stage turbine disk of the low-pressure turbine rotor and the partition, a final-stage turbine disk of the low-pressure turbine rotor, and the low-pressure turbine. The second space formed by the casing of the rotor, and the pressure in the second space is substantially equal to the pressure in the first space. And a second pressure adjusting means adjusted to be properly.

  In the present invention, the second pressure adjusting means adjusts the pressure in the second space so as to be approximately equal to the first space. As a result, the thrust load acting on the turbine disk due to the pressure difference between the first space and the second space can be reduced, and the thrust load of the low-pressure turbine rotor can be reduced. At this time, since the second pressure adjusting means communicates the first space and the second space with, for example, a communication hole provided in the low pressure turbine rotor, for example, a structure in which a balance piston is provided on the upstream side of the low pressure turbine rotor. Thus, the axial dimension of the two-shaft gas turbine does not increase. Therefore, the thrust load of the low-pressure turbine rotor can be reduced without increasing the axial dimension.

  (5) In the above (4), preferably, the second pressure adjusting means has a seal portion that is provided in the second space and suppresses leakage of high-pressure air in the second space.

  (6) In the above (4) or (5), preferably, the second pressure adjusting means is provided in the low-pressure turbine rotor, and has a communication hole that communicates the first space and the second space. Also have.

  According to the present invention, it is possible to reduce the thrust load of the low-pressure turbine rotor without increasing the axial dimension.

  Embodiments of the present invention will be described below with reference to the drawings.

A first embodiment of the present invention will be described with reference to FIGS.
FIG. 2 is a diagram schematically illustrating the overall configuration of the first embodiment of the two-shaft gas turbine of the present invention.

  In FIG. 2, the two-shaft gas turbine is roughly composed of a gas generator 1 and a power turbine 2. The gas generator 1 is connected to a compressor 4 that compresses the intake air 3 a that has been taken in to generate compressed air 3 b, a combustor 5 that mixes and burns the compressed air 3 b and fuel, and a compressor rotor 6 of the compressor 4. And a high-pressure turbine 9 including a high-pressure turbine rotor 8 that is rotationally driven by a high-temperature and high-pressure combustion gas 7 a from the combustor 5. The power turbine 2 includes a low-pressure turbine 12 that is connected to a load (for example, a generator, a compressor, a pump, and the like) 10 and includes a low-pressure turbine rotor 11 that is rotationally driven by the combustion gas 7 b that has passed through the high-pressure turbine 9.

  Then, the high-pressure turbine rotor 8 is rotationally driven by the combustion gas 7 a introduced from the combustor 5 to the high-pressure turbine 9, and the compressor rotor 6 is rotationally driven together with this to generate the compressed air 3 b, and passes through the high-pressure turbine 9. The low pressure turbine rotor 11 is driven to rotate by the combustion gas 7 b introduced into the low pressure turbine 12 to drive the load 10. Further, the combustion gas 7c that has passed through the low-pressure turbine 12 is discharged after being guided to, for example, a purification device.

  FIG. 1 is a partial sectional view showing a detailed structure of the low-pressure turbine 12 according to the present embodiment. In FIG. 1, for the sake of convenience, the high-pressure turbine rotor 8 is shown only for the final stage moving blades described later. The combustion gases 7b and 7c flow from the upstream side (left side in FIG. 1) to the downstream side (right side in FIG. 1).

  In FIG. 1, the low-pressure turbine 12 includes a plurality of stages of shrouds 13 provided in an annular shape in a substantially cylindrical turbine casing (not shown), and a first stage provided in an annular shape by being supported by the shrouds 13. A stationary blade (inlet stationary blade) 14, a first-stage moving blade 15 arranged annularly downstream of the first-stage stationary blade 14, and an outer peripheral side of the moving blade 15 (upper side in FIG. 1) And the low-pressure turbine rotor 11 provided in the above. Further, a substantially disc-shaped partition wall 16 is provided on the inner peripheral side (lower side in FIG. 1) of the first stage stationary blade 14, and the final stage moving blade 17 is provided on the outer peripheral side by the partition wall 16. The high pressure turbine rotor 8 and the low pressure turbine rotor 11 are separated.

  The low-pressure turbine rotor 11 includes a first-stage turbine disk 18 having a first-stage rotor blade 15 provided on the outer peripheral side, and a stub that connects the first-stage turbine disk 18 and the load 10 (see FIG. 1 described above). A casing 20 that includes the shaft 19 and encloses the stub shaft 19 is provided. The low-pressure turbine rotor 11 is disposed in the casing 20 and is rotatably supported via radial bearings 21A and 21B that receive a radial load. The stub shaft 19 is provided with a substantially annular thrust collar 22 for restricting movement of the low-pressure turbine rotor 11 in the axial direction (left-right direction in FIG. 1), and both axial sides of the thrust collar 22 (FIG. 1). Thrust bearings 23 </ b> A and 23 </ b> B that receive the thrust load of the low-pressure turbine rotor 11 are disposed on the middle left and right sides).

  The stationary blade 14 accelerates the combustion gas 7b from the high-pressure turbine 9, and the low-pressure turbine rotor 11 provided with the moving blade 15 is rotated by the combustion gas 7b. Further, the combustion gas 7c that has passed through the moving blades 15 is exhausted after being led to, for example, a purification device through the diffuser 24 and the like.

  At this time, since the first stage stationary blade 14 and the moving blade 15 are disposed in the combustion gas flow path (gas path) 25, the temperature becomes high. Therefore, as indicated by an arrow 26 in FIG. 1, the compressed air extracted from the compressor 4 is introduced as cooling air into the first stage stationary blade 14 through the turbine casing to cool the stationary blade 14. ing.

  A first cavity 27 is formed by the first stage turbine disk 18 and the partition wall 16, and a part of the air from the first stage stationary blade 14 is supplied to the first cavity 27 through the supply hole 28. . As a result, the pressure of the first cavity 27 is slightly higher than the pressure of the gas path 25 between the first stage stationary blade 14 and the first stage moving blade 15, and prevents the combustion gas 7 b from entering from the gas path 25. It is supposed to be.

  A second cavity 29 is formed by the first stage turbine disk 18 and the casing 20. Here, as a major feature of the present embodiment, the second cavity 29 includes a seal portion (for example, a labyrinth seal, a honeycomb seal, a brush seal, etc.) 30A that cooperates between the first stage turbine disk 18 and the casing 20. 30B, and is formed on the outer peripheral side of the gas path side seal portion 30A and the inner peripheral cavity 29a formed between these seal portions 30A and 30B (in other words, on the inner peripheral side of the gas path side seal portion 30A). It is comprised with the outer peripheral side cavity 29b.

  The casing 20 is provided with an introduction hole 31 that opens to the inner peripheral cavity 29a, and compressed air extracted from the compressor 4 is supplied to the inner peripheral cavity 29a via the high-pressure air supply path 32, and the inner peripheral cavity The pressure of 29 a is adjusted to be higher than the pressure of the first cavity 27.

  Further, the outer peripheral side cavity 29b is slightly leaked from the seal portion 30A and high pressure air is introduced, and the pressure thereof is slightly higher than the pressure of the gas path 25 on the downstream side of the first stage moving blade 15 (however, the outer peripheral cavity 29b The pressure of the side cavity 29b is lower than the pressure of the first cavity 27), and the combustion gas 7c from the gas path 25 is prevented from entering.

  In addition, in the above, the 1st cavity 27 comprises the 1st space of each claim, and the inner peripheral side cavity 29a comprises the 2nd space of each claim. The compressor 4 and the high pressure air supply path 32 constitute high pressure air supply means.

  Next, the operation and effect of this embodiment will be described.

  Along with the operation of the two-shaft gas turbine, the compressor 4 generates compressed air 3b compressed to a predetermined pressure by the rotation of the compressor rotor 6, and the combustor 5 mixes the compressed air 3b and fuel. Combustion produces combustion gas 7a. Then, the high pressure turbine rotor 8 is rotationally driven by the combustion gas 7a in the high pressure turbine 9 to rotationally drive the compressor rotor 6, and the low pressure turbine rotor is driven by the combustion gas 7b that has passed through the high pressure turbine in the low pressure turbine 12. 11 is rotationally driven to drive the load 10.

  At this time, due to the pressure difference in the flow direction of the combustion gases 7b and 7c in the low-pressure turbine 12 (upstream pressure> downstream pressure), the thrust load in the downstream direction (the above-described figure) is applied to the rotor blade 15 of the low-pressure turbine rotor 11. 1 is illustrated by the arrow 33 in FIG. Next, FIG. 3 shows a partial sectional view showing a detailed structure of a low-pressure turbine according to a comparative example for explaining the operation of the present embodiment. In this FIG. 3, the same code | symbol is attached | subjected to the part equivalent to 1st Embodiment of the said invention, and description is abbreviate | omitted suitably.

  In FIG. 3, the introduction hole 31 is not provided in the casing 20, and the seal portion 30 </ b> A is not provided in the second cavity 29. The pressures of the first and second cavities 27 and 29 are set higher than the corresponding gas paths 25 in order to prevent the combustion gases 7 b and 7 c from entering from the gas paths 25. Therefore, a pressure difference between the first cavity 27 and the second cavity 29 (the pressure of the first cavity 27> the pressure of the second cavity 29) is generated corresponding to the pressure difference between the combustion gases 7b and 7c. Thereby, a downstream thrust load (illustrated by an arrow 34 in FIG. 3) acting on the first stage turbine disk 18 is generated, and acts on the rotor blade 15 due to the pressure difference in the flow direction of the combustion gases 7b and 7c described above. The thrust load of the low-pressure turbine rotor 11 is increased by adding to the thrust load in the downstream direction.

  In the present embodiment, the second cavity 29 is provided with seal portions 30A and 30B that suppress leakage of high-pressure air, and high-pressure air is supplied to the inner peripheral cavity 29a formed between the seal portions 30A and 30B. The pressure in the inner peripheral cavity 29 a is adjusted to be higher than the pressure in the first cavity 27. As a result, an upstream thrust load (indicated by the arrow 35 in FIG. 1 described above) acting on the first stage turbine disk 18 is generated by the pressure difference between the first cavity 27 and the inner peripheral cavity 29a, and the combustion gas described above is generated. Since the pressure difference in the flow direction of 7b and 7c cancels out the thrust load in the downstream direction acting on the rotor blade 15, the thrust load of the low-pressure turbine rotor 11 can be reduced. At this time, since high pressure air is introduced into the inner peripheral cavity 29a from the introduction hole 31 provided in the casing 20, a two-shaft gas turbine (for example, a structure in which a balance piston is provided upstream of the low pressure turbine rotor 11). More specifically, the axial dimension of the low-pressure turbine rotor 11 and related components is not increased, and the number of parts to be cooled that are exposed to the combustion gas 7b and become high temperature does not increase. Therefore, the thrust load of the low-pressure turbine rotor 11 can be reduced without increasing the axial dimension.

  Further, since the seal portions 30A and 30B are provided in the inner peripheral side cavity 29a, the amount of high pressure air leaked from the inner peripheral side cavity 29a can be reduced, and the amount of high pressure air supplied to the inner peripheral side cavity 29a can be reduced. And thermal efficiency is improved.

  Further, by reducing the thrust load of the low-pressure turbine rotor 11, the thrust bearings 23A and 23B can be reduced in size, and the manufacturing cost can be reduced. Further, the downsizing of the thrust bearings 23A and 23B makes it possible to reduce the outer dimensions of the thrust collar 22, and the thrust bearings 23A. The reliability with respect to the baking of 23B can be improved. Further, the thrust bearing 23A. Since the bearing loss is reduced by the downsizing of 23B, the thermal efficiency is improved.

  In the present embodiment, the thrust load of the low-pressure turbine rotor 11 can be adjusted by adjusting the pressure of the compressed air supplied to the inner peripheral cavity 29a. As a result, the thrust load of the low-pressure turbine rotor 11 can be adjusted according to the operating state of the two-shaft gas turbine, such as starting, rated operation, trip, etc., and the reliability of the thrust bearings 23A, 23B can be improved. .

  In the first embodiment, the low-pressure turbine 12 in which the stationary blades 14 and the moving blades 15 are configured in one paragraph has been described as an example. However, the present invention is not limited to this example. May be. FIG. 4 is a cross-sectional view showing a detailed structure of a low-pressure turbine 12 ′ configured in two paragraphs according to the first modification. In FIG. 4, parts that are the same as in the above embodiment are given the same reference numerals, and descriptions thereof are omitted as appropriate.

  In this modified example, the low-pressure turbine 12 ′ includes a first stage and a second stage stationary blades 36a and 36b that are engaged and supported by a plurality of stages of shrouds 13, and downstream of the stationary blades 36a and 36b. First and second stage rotor blades 37a, 37b arranged annularly on the side (right side in FIG. 4), and the low pressure turbine rotor provided with these rotor blades 37a, 37b on the outer peripheral side (upper side in FIG. 4) 38.

  The low-pressure turbine rotor 38 includes solid or hollow first and second stage turbine disks 39a and 39b provided with first and second stage blades 36a and 36b, respectively, and turbine disks 39a and 39b. And a stub shaft 41 for connecting the second stage turbine disk 39b and the load 10, and the turbine disks 39a and 39b, the spacer 40, and the stub shaft 41 have a shaft. A plurality of stacking bolts 42 penetrating in the direction (left-right direction in FIG. 4) are fixedly held.

  A first cavity 27 ′ is formed by the first stage turbine disk 39 a and the partition wall 16, and a second cavity 29 ′ is formed by the second stage turbine disk 39 b (and the flange portion 41 a of the stub shaft 41) and the casing 20. Has been. Like the first embodiment, the second cavity 29 ′ includes seal portions 30A and 30B, and an inner peripheral cavity 29a ′ formed between the seal portions 30A and 30B and the gas path side seal portion 30A. The outer peripheral side cavity 29b 'is formed on the outer peripheral side.

  A third cavity 43 is formed on the inner peripheral side (upper side in FIG. 4) between the first stage turbine disk 39a and the spacer 40, and the inner peripheral side between the second stage turbine disk 39b and the spacer 40. A fourth cavity 44 is formed in the. The pressures of the third and fourth cavities 43 and 44 are set slightly higher than the pressures of the corresponding gas paths 25 in order to prevent the combustion gas 7b from entering the gas paths 25. Accordingly, the pressure decreases in the order of the first cavity 27 ′, the third cavity 43, the fourth cavity 44, and the outer peripheral side cavity 29 b ′.

  Also in the present modification, as in the first embodiment, high-pressure air extracted from the compressor 4 is introduced into the inner peripheral cavity 29a ′ through the introduction hole 31, and the pressure in the inner peripheral cavity 29a ′ is changed to the first cavity 27 ′. Adjust the pressure to be higher than As a result, a thrust load in the upstream direction (shown by the arrow 35 'in FIG. 4) is generated due to the pressure difference between the first cavity 27' and the inner peripheral cavity 29a ', so that the pressure in the flow direction of the combustion gases 7b and 7c The thrust load of the low-pressure turbine rotor 38 can be reduced by canceling out the thrust load in the downstream direction acting on the rotor blades 37a and 37b (shown by the arrow 33 'in FIG. 4) due to the difference. Therefore, the thrust load of the low-pressure turbine rotor 38 can be reduced without increasing the axial dimension as in the first embodiment.

  In the first embodiment and the first modification, the high-pressure air supply unit has been described by taking as an example a configuration in which compressed air extracted from the compressor 4 is supplied via the high-pressure air supply path 32. For example, a separately prepared compressor, blower, or the like may be used. In this case, the same effect as described above can be obtained.

  A second embodiment will be described with reference to FIG. This embodiment is an embodiment in which a communication hole is provided in a low-pressure turbine rotor.

  FIG. 5 is a partial cross-sectional view showing the detailed structure of the low-pressure turbine according to the present embodiment. In FIG. 5, parts that are the same as in the first embodiment are given the same reference numerals, and descriptions thereof are omitted as appropriate.

  In the present embodiment, the first stage turbine disk 18 of the low-pressure turbine rotor 11 is provided with a communication hole 45 in the axial direction (left-right direction in FIG. 5). The inner peripheral cavity 29a is communicated. Then, as indicated by an arrow 46 in the figure, the high pressure air in the first cavity 27 is introduced into the inner peripheral cavity 29a through the communication hole 45, and the high pressure air from the inner peripheral cavity 29a is sealed by the seal portions 30A and 30B. Since the leakage is suppressed, the pressure of the inner peripheral cavity 29 a becomes substantially equal to the pressure of the first cavity 27.

  As described above, according to the present embodiment, only the pressure in the inner peripheral cavity 29a is higher than the pressure difference between the first cavity 27 and the second cavity 29 in the comparative example shown in FIG. The differential pressure can be reduced. Therefore, the thrust load in the downstream direction acting on the first stage turbine disk 18 due to the pressure difference between the first cavity 27 and the second cavity 29 can be reduced, and the thrust load of the low-pressure turbine rotor 11 can be reduced.

  Further, since the communication hole 45 is only provided in the low-pressure turbine rotor 11, the axial dimension is not increased unlike a structure in which a balance piston is provided on the upstream side of the low-pressure turbine rotor 11, for example. Further, as compared with the first embodiment, since the high-pressure air supply path 32 is not provided, the structure can be further simplified and the manufacturing cost can be reduced.

  In the second embodiment, the low-pressure turbine 12 in which the stationary blades 14 and the moving blades 15 are configured in one paragraph has been described as an example. However, the present invention is not limited to this, and may be configured in, for example, two or more paragraphs. May be. FIG. 6 is a cross-sectional view showing a detailed structure of a low-pressure turbine 12 ′ configured in two paragraphs according to the second modification. In FIG. 6, parts that are the same as in the first modified example are given the same reference numerals, and descriptions thereof are omitted as appropriate.

  In this modification, a communication hole 47 is provided in the shaft center of the low-pressure turbine rotor 38 ′, for example, the stacking bolt 42 ′ (or the flange portions of the turbine disks 39a and 39b, the spacer 40, and the stacking bolt 41). Communication hole 47 may be provided so as to penetrate 41 in the axial direction), and the first cavity 27 ′ communicates with the inner peripheral cavity 29 a ′ through the communication hole 47. Then, as indicated by an arrow 48 in the figure, the high pressure air in the first cavity 27 ′ is introduced into the inner peripheral side cavity 29a ′ through the communication hole 47, and the high pressure in the inner peripheral side cavity 29a ′ by the seal portions 30A and 30B. Since air leakage is suppressed, the pressure in the inner peripheral cavity 29a ′ becomes substantially equal to the pressure in the first cavity 27 ′.

  Therefore, also in this modified example, the thrust load of the low-pressure turbine rotor 38 ′ can be reduced without increasing the axial dimension as in the second embodiment.

It is a fragmentary sectional view showing the detailed structure of the low pressure turbine which constitutes a 1st embodiment of the 2 axis type gas turbine of the present invention. 1 is a circuit diagram illustrating a schematic configuration of a first embodiment of a two-shaft gas turbine of the present invention. It is a fragmentary sectional view showing the detailed structure of the low pressure turbine which comprises the 2-shaft type gas turbine by the comparative example of this invention. It is a fragmentary sectional view showing the detailed structure of the low pressure turbine which comprises the 1st modification of the 2-shaft type gas turbine of this invention. It is a fragmentary sectional view showing the detailed structure of the low pressure turbine which constitutes a 2nd embodiment of the 2 axis type gas turbine of the present invention. It is a fragmentary sectional view showing the detailed structure of the low pressure turbine which comprises the 2nd modification of the two-shaft gas turbine of this invention.

Explanation of symbols

3b Compressed air 4 Compressor (High pressure air supply means)
5 Combustor 7a Combustion gas 7b Combustion gas 8 High pressure turbine rotor 9 High pressure turbine 10 Load 11 Low pressure turbine rotor 12 Low pressure turbine 16 Bulkhead 18 First stage turbine disk (first stage turbine disk, last stage turbine disk)
20 Casing 27 First cavity (first space)
29a Inner peripheral cavity (second space)
30A Seal part 30B Seal part 31 Introduction hole 32 High-pressure air supply path (high-pressure air supply means)
38 Low-pressure turbine rotor 39a First stage turbine disk (first stage turbine disk)
39b Second stage turbine disk (last stage turbine disk)
45 Communication hole 47 Communication hole

Claims (6)

A compressor, a combustor that mixes and burns compressed air and fuel from the compressor, and a high-pressure turbine that is connected to the compressor and includes a high-pressure turbine rotor that is rotationally driven by combustion gas from the combustor; A two-shaft gas turbine having a low pressure turbine separated from the high pressure turbine rotor by a partition wall, connected to a load, and having a low pressure turbine rotor driven to rotate by the combustion gas from the high pressure turbine;
The low-pressure turbine includes a first space formed by a first-stage turbine disk of the low-pressure turbine rotor and the partition wall, and a second space formed by a final-stage turbine disk of the low-pressure turbine rotor and a casing of the low-pressure turbine rotor. And a first pressure adjusting means for adjusting the pressure in the second space so as to be higher than the pressure in the first space.   2. The two-shaft gas turbine according to claim 1, wherein the first pressure adjusting means includes a seal portion that is provided in the second space and suppresses leakage of high-pressure air in the second space. A two-shaft gas turbine.   3. The two-shaft gas turbine according to claim 1, wherein the first pressure adjusting means includes an introduction hole provided in the casing that forms the second space, and the introduction hole extends from the introduction hole to the second space. A two-shaft gas turbine, further comprising high-pressure air supply means for supplying air having a pressure higher than that of the first space. A compressor, a combustor that mixes and burns compressed air and fuel from the compressor, and a high-pressure turbine that is connected to the compressor and includes a high-pressure turbine rotor that is rotationally driven by combustion gas from the combustor; A two-shaft gas turbine having a low pressure turbine separated from the high pressure turbine rotor by a partition wall, connected to a load, and having a low pressure turbine rotor driven to rotate by the combustion gas from the high pressure turbine;
The low-pressure turbine includes a first space formed by a first-stage turbine disk of the low-pressure turbine rotor and the partition wall, and a second space formed by a final-stage turbine disk of the low-pressure turbine rotor and a casing of the low-pressure turbine rotor. And a second pressure adjusting means for adjusting the pressure in the second space so as to be substantially equal to the pressure in the first space.   5. The two-shaft gas turbine according to claim 4, wherein the second pressure adjusting means includes a seal portion that is provided in the second space and suppresses leakage of high-pressure air in the second space. A two-shaft gas turbine. 6. The two-shaft gas turbine according to claim 4, wherein the second pressure adjusting means further includes a communication hole provided in the low-pressure turbine rotor and communicating the first space and the second space. A two-shaft gas turbine characterized by the above.

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