JPH04241743A - Cooling air passage for gas turbine - Google Patents

Abstract

PURPOSE:To shorten a bearing span of a rotor shaft while easily and surely holding a width of required minimum limit of a cooling air passage by forming a protruding part for a spacer in the cooling air passage between a scroll chamber side end wall part and a compressor side heat shield plate. CONSTITUTION:A scroll chamber 16 is provided so as to surround a rotor shaft in a turbine casing 13. A combustion gas passage S is provided in an axial center side from the scroll chamber 16 to arrange turbine rotor blades 17 and nozzle blades 18 in the passage. Further, a heat shield plate 43 is arranged between an end wall part 32 of the scroll chamber 16 and a supporting wall 33 of a compressor A thus to partition a cooling air passage 60. Here in the end wall part 32, a spacer protruding part 70, protruded to a side of the heat shield plate 43, is formed. In this way, a width of the cooling air passage 60, fluctuated according to engine vibration or the like, is easily and surely held to a value of required minimum limit. Accordingly, ensuring cooling air and shortening a bearing span of the rotor shaft can be attained.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention provides a heat shield plate disposed between a scroll chamber in a turbine casing and a compressor, and a heat shield plate formed between the heat shield plate and an end wall portion of the scroll chamber. The present invention relates to a cooling air passage of a gas turbine that supplies a portion of air discharged from a compressor to turbine nozzle blades as cooling air.

0002

2. Description of the Related Art A structure in which a heat shield plate is interposed between a scroll chamber and a compressor is disclosed in Japanese Patent Application Laid-Open No. 117611/1983. In this prior art, the heat shield plate and the end wall of the scroll chamber are simply opposed to each other. Therefore, in order to avoid interference between the two due to engine vibration or thermal deformation, a sufficient width is secured in the axial direction.

0003

However, if the axial clearance is widened, the bearing span of the rotor shaft becomes long, and as a result, the shaft diameter also becomes excessive in order to avoid dangerous speeds of the rotor shaft.

0004

[Means for Solving the Problems] In order to solve the above problems and to make the bearing span of the rotor shaft more compact and to stabilize the cooling performance of the turbine nozzle blades, the present invention provides a scroll chamber in a turbine casing and a compressor. A heat shield is disposed between the compressor and the end wall of the scroll chamber, and a part of the air discharged from the compressor is supplied to the turbine nozzle blade as cooling air. In the cooling air passage of a gas turbine, a protrusion is formed on at least one of the end wall of the scroll chamber and the heat shield plate so as to protrude toward the other member to ensure a gap in the cooling air passage. It is characterized by what it does.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an overall schematic diagram of a gas turbine equipped with cooling air passages according to the present invention, and the overall structure will be briefly explained in FIG. The gas turbine includes a compressor A, a turbine section B, and a combustor C. The compressor A has an outer shell composed of an intake housing 3, a compressor bearing housing 4, an intermediate housing 5, etc., and includes a centrifugal force-type front-stage compression section 11 and a rear-stage compression section 12, and both compression sections 11 and 12 are They mesh with each other via a meshing portion 10 so as to rotate integrally with each other, and are interlocked and connected via a seal housing 15 to a disk 19 for supporting rotor blades of the turbine section B.

A scroll chamber 16 is provided in the turbine casing 13 so as to surround the rotor shaft (turbine main shaft) 1.
A radially outer end of the scroll chamber 16 is connected to a combustion gas discharge portion of the combustor C via a combustion gas communication pipe 8. A combustion gas passage S is provided closer to the axis than the scroll chamber 16, and the combustion gas passage S includes a turbine blade section consisting of a plurality of turbine rotor blades (moving blades) 17 and a plurality of nozzle blades (stationary blades) 18. It is located. A scroll chamber 16 is provided at the exhaust gas upstream end of the combustion gas passage S.
The discharge port on the axial center side is opened, and combustion gas is supplied from the discharge port in the axial direction of arrow R.

Each turbine rotor blade 17 is fixed to the outer peripheral end of a disk 19 for supporting the rotor blade.
The disks 19 are connected to each other through meshing portions so as to be able to rotate together, and are also interlocked to a coupling 25, which is spline-fitted to the rotor shaft 1 and rotates together with the rotor shaft. ing. The rotor shaft 1 extends along the inner peripheral side of the disk 19 toward the compressor A side, passes through the compressor A, etc., and is used as a power extraction shaft for driving a load such as a generator.

[0008] Each nozzle blade 18 is fixedly supported by a cylindrical turbine case 20 for supporting the nozzle on the outer circumferential side thereof, and a cylindrical turbine case 20 for supporting the nozzle is provided on the radially outer side of the turbine case 20. A containment ring (cylindrical partition wall) 21 is arranged to prevent debris from scattering to the outside.

A cylindrical exhaust diffuser 28 for decelerating exhaust gas is attached to the opening of the turbine casing 13, and communicates with the exhaust gas outlet side of the combustion gas passage S, and is connected to the downstream side of the exhaust diffuser 28. The end portion is connected to, for example, an exhaust muffler.

[0010] The air sequentially compressed in the front-stage compression section 11 and the rear-stage compression section 12 of the compressor A is transferred to the turbine casing 13.
The combustion gas is sent to the combustor C through the compressed air chamber 30, mixed with fuel and used for combustion, and the combustion gas generated there is supplied to the combustion gas passage S through the scroll chamber 16. After the turbine rotor blades 17 are rotated within the combustion gas passage S, the combustion gas passes through an exhaust diffuser 28 and is sent to an exhaust muffler or the like.

In FIG. 2 showing an enlarged detailed view of portion II in FIG. 1, a support wall 33 for forming an air passage is fixed to the turbine section side of the intermediate housing 5 of the compressor A. A compressed air passage 45 is formed between the end wall 5a of the intermediate housing 5, the radially inner end of the passage 45 communicates with the rear compression section 12, and the outer end communicates with the compressed air in the turbine casing 13. It communicates with room 30. Support wall 3
An outer seal housing 40 facing the seal housing 15 from the outside is fixed to the inner end of the seal housing 3.
A pair of labyrinth seals 47, 48 are formed by both the seal housings 15, 40 and spaced apart from each other in the axial direction. A nozzle housing 41 is fixed to the end face of the outer seal housing 40, and a first stage turbine nozzle blade 18 is fixed to the nozzle housing 41.

The scroll chamber 16 is formed of a main body portion 31 made of sheet metal and an end wall portion 32 made of sheet metal on the compressor A side, and is configured such that the flow cross-sectional area becomes smaller as it goes inward in the radial direction. ing. The scroll chamber 16 is fixed to the turbine casing 13 at multiple locations on the radially outer end of the main body 31 with fixing pins 50, etc., and is attached at multiple locations on the outer end on the compressor side. A mounting piece 35 is welded to the outer end of the support wall 33 with a bolt 36.
Fixed by The inner end of the end wall 32 is curved toward the combustion gas passage S side to form a discharge port, and a plurality of inner mounting pieces 37 are welded to the inner end. extends toward the compressor A side while being gently bent, and is welded to an annular mounting plate 46 having an L-shaped cross section. The annular mounting plate 46 integrally includes a cylindrical portion 46a, a vertical plate portion 46b, and an extension portion 46c at the inner end.
is the seal housing 40 and the nozzle blade housing 41.
It is held together with the shim 51 between them. A small hole 65 for passing cooling air is formed in the cylindrical portion 46a. Further, a socket portion 53 that projects in the axial direction is formed in the radially inward portion of the main body portion 31, and the socket portion 53 fits into an annular projection portion 57 formed on the cover 56 of the turbine case 20. There is.

End wall portion 32 of scroll chamber 16 and compressor A
A heat shield plate 43 is arranged between the supporting walls 33 with a certain gap from the scroll chamber end wall 32, and a cooling air passage 60 is formed between this and the scroll chamber end wall 32. . The inner end of the heat shield plate 43 is fixed to the outer end of the seal housing 40.

A spacer protrusion 70 that protrudes toward the heat shield plate 43 is formed on the end wall 32 of the scroll chamber 16, and the axial height H of the spacer protrusion 70 is the same as when the operation is stopped. The width D of the cooling air passage 60 in the axial direction is set to be slightly smaller than that of the cooling air passage 60, and a plurality of the cooling air passages 60 are formed at intervals in the circumferential direction. Further, the spacer protrusion 70 is formed in the radially inner portion of the end wall 32,
This is the part that extends to the compressor A side.

The flow of cooling air will be explained. In FIG. 1, most of the air supplied from the latter stage compression section 12 to the compressed air chamber 30 is supplied to the combustor C as described above, but in FIG. 60 from the outer end, reaches the inner end, and enters the small hole 6
5 to cool the vicinity of the discharge part of the scroll chamber end wall part 32, and further pass through the gap G between the mounting plate 46 and the discharge side edge of the end wall part 32 as shown by the arrow to cool the nozzle blade 18 part. is ejected to cool the nozzle blades 18.

[0016]

[Another Embodiment] In the illustrated embodiment, the spacer protrusion 70 is formed on the end wall portion 32 of the scroll chamber, but the protrusion may also be formed on the heat shield plate 43. In this case, of course, it protrudes toward the scroll chamber end wall 32 side.

[0017]

As explained above, according to the present invention, the cooling air passage 60 is formed between the end wall portion 32 of the scroll chamber 16 and the heat shield plate 43 to cool the nozzle blade 18, and the end wall portion 32 or the heat shield plate 43 is formed with a spacer protrusion 70 that protrudes toward the other member: (1) The relative distance between the scroll chamber 16 and the compressor A can be minimized as much as possible. When contracted, the cooling air passage 60 maintains a minimum width equal to or greater than the height of the protrusion 70 even if there is engine vibration or the like. This ensures a constant flow of cooling air and ensures reliable cooling of the turbine nozzle blades. (2) By shortening the width of the cooling air passage 60 and shortening the bearing span of the rotor shaft 1, the critical speed of the rotor shaft can be largely avoided, and the high speed of the gas turbine,
It can contribute to high output.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical cross-sectional view of the entire gas turbine to which the present invention is applied.

FIG. 2 is an enlarged detailed view of part II in FIG. 1.

[Explanation of symbols]

13 Turbine casing 16 Scroll room 17 Turbine rotor blade 18 Turbine nozzle blade 32 Scroll chamber end wall 33 Supporting wall 43 Heat shield plate 60 Cooling air passage 70 Protruding part for spacer A Compressor B Turbine

Claims (1)

[Claims] 1. A heat shield plate is disposed between a scroll chamber in a turbine casing and a compressor, and a heat shield plate is formed between the heat shield plate and an end wall of the scroll chamber, and a heat shield plate is formed between the heat shield plate and an end wall of the scroll chamber, and a heat shield plate is provided between the scroll chamber and the compressor. In the cooling air passage of the gas turbine that supplies a part of the cooling air to the turbine nozzle blades, the cooling air passage protrudes from at least one of the end wall of the scroll chamber or the heat shield plate so as to be able to abut against the other member. A cooling air passage for a gas turbine, characterized in that a protrusion is formed to ensure a gap in the cooling air passage.