JP2009114866A - Sealing apparatus of gas turbine plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing apparatus of gas turbine plant capable of maintaining sealing effects by surface contact with wall surfaces of seal grooves of a sealing member, even if seal grooves formed on facing surfaces of divided structures of adjacent gas turbines are displaced in radial direction by thermal deformation. <P>SOLUTION: A component member of a gas turbine is composed of divided structures (13A, 13B) having facing surfaces facing via a gap, and includes seal grooves 25A, 25B with rectangular-shaped cross-section formed opposed to the facing surfaces 24A, 24B of these divided structures, respectively, and a sealing member 28 mounted to straddle over these facing seal grooves, for blocking the gap. The sealing member is configured to have two sheets of sealing plates 29A, 29B spaced apart from each other in a direction where differential pressure acts, and elastic elements (30A, 30B, 31A, 31B) which establishes connection between these two sheets of sealing plates, and to bring one of the sealing plates into surface contact with wall surfaces inside the seal grooves utilizing the differential pressure. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sealing device for gas turbine equipment, and more particularly to a sealing device for gas turbine equipment suitable for preventing leakage of cooling air of a gas turbine.

  In gas turbines of normal gas turbine equipment, the working gas is heated for the purpose of improving the thermal efficiency. In particular, the stationary blades and moving blades of the gas turbine exposed in the working gas flow path are hot. Cooling air is circulated inside the blade so that it can withstand.

  This type of gas turbine cooling system that is generally adopted is called an open cooling system. The high-pressure air extracted from the air compressor is used as cooling air, and this high-pressure air passes through the casing and gas turbine structure. To cool inside the blade. A part of the compressed air after cooling the inside of the blade is discharged into the working gas flow path from a film cooling hole on the outer surface of the blade, a trailing edge cooling hole of the blade, or the like. On the other hand, the remaining part of the compressed air after cooling is supplied into the wheel space in order to prevent the working gas in the working gas passage from leaking into the wheel space, and finally into the working gas passage. Released.

  By the way, a plurality of stationary blades are integrally formed between the inner and outer annular endwalls, but in consideration of thermal elongation due to temperature rise during operation, a plurality of inner and outer endwalls including the stationary blades are circumferentially arranged. The stationary blade body segment is formed by dividing the segment. Then, in order to secure a gap on the facing surface and close the gap so that the facing surfaces of the stationary blade body segments adjacent in the circumferential direction do not contact during thermal expansion, for example, as shown in Patent Document 1, both stationary blades A seal plate is mounted across the seal grooves formed on the opposing surfaces of the body segments.

  With such a configuration, it is possible to prevent the compressed air from leaking into the working gas flow path via the gap.

US Pat. No. 5,158,430

  However, the conventional configuration has the following problems. That is, in the adjacent stationary blade body segment, the two seal grooves may be displaced in the radial direction due to thermal deformation in the radial direction of the stationary blade. As a result, if the seal plate is tilted in the two seal grooves to reduce the sealing effect, or if the seal plate is in contact with the opening edge of the seal groove and the thermal deformation further proceeds in the radial direction, There is a risk that the end wall may be deformed, as well as being bent to further reduce the sealing effect.

  An object of the present invention is to provide a seal by surface contact with an inner wall of a seal groove of a seal member even if a seal groove formed on an opposing surface of a split structure of an adjacent gas turbine is displaced in the radial direction by thermal deformation of the split structure. An object of the present invention is to provide a sealing device for gas turbine equipment that can maintain the effect.

  The gas turbine component member is composed of a divided structure having opposing surfaces opposed to each other through a gap, and has a rectangular cross-sectional seal groove formed to face the opposed surfaces of the divided structure, and the opposed seal grooves. A sealing member that is mounted across the gap and seals the gap, and a sealing device for a gas turbine facility in which differential pressure acts on both sides of the sealing member as a boundary. The sealing member is separated in a direction in which the differential pressure acts The two sealing plates and an elastic body connecting the two sealing plates, and one of the two sealing plates is brought into surface contact with the wall surface in the sealing groove using the differential pressure. It was configured as follows.

  With the above configuration, when adjacent divided structures are displaced in the radial direction in the same way due to thermal deformation, the sealing plate is similarly applied to the wall surface in the sealing groove on both sides by the differential pressure acting on the sealing plate. Since the surface contact is made, the gap is closed and the sealing effect is maintained. When adjacent divided structures are displaced differently in the radial direction due to thermal deformation, one spaced apart seal plate comes into surface contact with the wall surface in one seal groove and the other seal plate is in contact with the other. Since the surface contact is made with the wall surface of the seal groove, the gap is closed and the sealing effect is maintained. As a result, even if the seal groove formed on the opposing surface of the split structure of the adjacent gas turbine is displaced in the radial direction due to thermal deformation of the split structure, the sealing effect is maintained by surface contact with the inner wall of the seal groove of the seal member. It is possible to obtain a seal device for a gas turbine facility.

  A gas turbine equipment sealing device according to the present invention will be described below with reference to FIGS.

  The gas turbine equipment 1 is broadly divided into an air compressor 2 that compresses air a1, a combustor 3 that mixes and burns compressed air a2 and fuel to obtain high-temperature combustion gas (working gas) G1, and combustion gas. A gas turbine power generation facility is configured by connecting a generator 5 driven by the gas turbine 4 to such a gas turbine facility 1. The exhaust gas G2 after driving the gas turbine 4 is recovered and used for heat exchange and then discharged into the atmosphere.

  And in order to cool the gas turbine 4, the compressed air a3-a5 compressed with the air compressor 2 is supplied to each structure of the gas turbine 4. FIG.

  The gas turbine 4 has multistage stationary blades and moving blades, and an example of the configuration thereof will be described for the upstream two stages shown in FIG. The first stage stationary blade 7A and the second stage stationary blade 7B are positioned on the downstream side of the first stage stationary blade 6A and the second stage stationary blade 6B, respectively. The first stage stationary blade 6A and the second stage stationary blade 6B are casings via shrouds 8A and 8B. 9, the first stage moving blade 7 </ b> A and the second stage moving blade 7 </ b> B are supported by the rotor 10. The rotor 10 includes a first wheel 11A and a second wheel 11B, and a spacer 12 positioned therebetween, and these are integrally connected.

  The detailed configuration of the first stage stationary blade 6A and the second stage stationary blade 6B will be described with the second stage stationary blade 6B shown in FIG. 3 as a representative. The annular outer end wall 13 supported across the shrouds 8A and 8B and the outer end An annular inner end wall 14 that is concentric with the wall 13, a plurality of blade portions 15 that are installed at predetermined intervals in the circumferential direction, and a cavity that forms a cooling air cavity 16 on the outer diameter side of the outer end wall 13 A cover 17 and a diaphragm 19 that forms a diaphragm chamber 18 on the inner diameter side of the inner end wall 14 are provided. A working gas flow path is formed between the outer end wall 13 and the inner end wall 14. A seal fin 20 is provided on the inner diameter side of the diaphragm 19 so as to face the outer peripheral surface of the spacer 12 with a minute gap. In the second stage stationary blade 6B, a plurality of stationary blade body segments 21 are formed by dividing the outer end wall 13 and the inner end wall 14 in the circumferential direction with a plurality of blade portions 15 as a unit.

  When the gas turbine 4 configured in this manner is in operation, the high-temperature combustion gas G1 passes through the working gas flow path, so that the first stage stationary blade 6A and the second stage stationary blade 6B are heated and heated and deformed. Compressed air a3 is supplied for cooling the first stage stator blade 6A, compressed air a4 is supplied for cooling the second stage stator blade 6B, and compressed air a5 is supplied for cooling the first stage rotor blade 7A and the second stage rotor blade 7B. Yes.

  Here, the cooling will be described by taking the second stage stationary blade 6B as an example. The compressed air a4 supplied to the cooling air chamber 22 formed by the shrouds 8A and 8B, the casing 9, and the cavity cover 17 of the outer end wall 13 has a vent hole (not shown) provided in the cavity cover 17. Then, the air enters the cooling air cavity 16 and then passes through a cooling flow path (not shown) formed in the blade 15 to cool the blade 15, and a part of the compressed air a4 after cooling is a blade After being introduced into the working gas channel from the exhaust port of the cooling channel formed in the part, the remaining part is introduced into the diaphragm chamber 18 and then released into the wheel space 23A on the upstream side. A part of the discharged air discharged into the wheel space 23A is adjusted in flow rate by the seal fin 20 and introduced into the downstream wheel space 23B. Since the pressure of the discharge air discharged into each wheel space 23A, 23B is set to be higher than the pressure of the working gas G1 flowing through the working gas flow path, this discharged air acts as a seal air, and the working gas flow It is discharged into the road and prevents the working gas G1 from leaking into the wheel spaces 23A and 23B.

  When the outer end wall 13 of the stator blade segment 21 having the above configuration is developed, the arrangement shown in FIG. 4 is obtained. In other words, the outer endwalls 13A and 13B of the adjacent stationary blade body segments 21 and the so-called divided structure according to the present invention are adjacent to each other even if there is circumferential deformation due to thermal expansion during rated operation of the gas turbine 4. The gap δc is held between the opposing surfaces 24A and 24B of the outer end walls 13A and 13B so that the outer end walls 13A and 13B are in contact with each other to prevent thermal deformation. Therefore, the compressed air a4 for cooling supplied to the cooling air chamber 22 and the diaphragm chamber 18 leaks into the working gas flow path as indicated by arrows R1 and R2 shown in FIG. As a result, the cooling of the blade 15 is insufficient, or the effect of sealing the leakage of the combustion gas G1 in the working gas flow path is lost.

  Therefore, in the present embodiment, seal grooves 25A and 25B having a rectangular cross section are provided on the opposing surfaces 24A and 24B of the outer end walls 13A and 13B of the adjacent stationary blade body segment 21, respectively. Similarly, a seal groove 27 is provided on the facing surface 26 of the adjacent inner end wall 14. A seal member 28 is mounted across the seal grooves 25A, 25B, and 27 to prevent leakage of the compressed air a4 from the gap δc.

  The case where the seal member 28 is mounted in the seal grooves 25A and 25B will be described as an example. The seal member 28 has two seal plates 29A and 29B spaced apart in the height direction of the seal grooves 25A and 25B, in other words, in the radial direction of the outer end walls 13A and 13B. These seal plates 29A and 29B have a length straddling the seal grooves 25A and 25B, and come into surface contact with the wall surfaces in the height direction of the seal grooves 25A and 25B. The seal plate 29A is provided with plate springs 30A and 30B, which are elastic bodies, and the seal plate 29B is provided with plate springs 31A and 31B facing each other. These leaf springs 30A, 30B and 31A, 31B extend from the intermediate portion of the seal plates 29A, 29B toward the groove bottom wall 25a side of the seal grooves 25A, 25B, and the groove bottoms respectively extend to the extended end portions thereof. Seal blocks 32A and 32B, which are second seal members that come into surface contact with the wall 25a, are fixed.

  Therefore, when the adjacent outer end walls 13A and 13B are not displaced differently in the radial direction, the seal member 28 mounted in the seal grooves 25A and 25B has a higher pressure on the outer diameter side than the combustion gas G1 on the inner diameter side. The seal plate 29B comes into surface contact with the inner diameter wall surfaces of the seal grooves 25A and 25B due to the differential pressure caused by the compressed air a4, so that leakage of the compressed air a4 from the gap δc is prevented.

  On the other hand, when the outer end walls 13A and 13B are thermally deformed only in the circumferential direction without being displaced differently in the radial direction and approach each other, the gap δc shown in FIG. 5 is reduced to the gap δc-a shown in FIG. Since the seal blocks 32A and 32B are in surface contact with the groove bottom wall 25a and the seal plate 29B is in surface contact with the inner wall surface of the seal grooves 25A and 25B by the action of the differential pressure, the compressed air a4 from the gap δc is obtained. Leakage can be effectively prevented by surface contact with the wall surfaces of the seal grooves 25A and 25B of the seal plate 29B and surface contact with the groove bottom wall 25a of the seal blocks 32A and 32B. At this time, the interval between the seal blocks 32A and 32B and the compression force of the leaf springs 30A, 30B and 31A, 31B are set so that the leaf springs 30A, 30B and 31A, 31B bend as much as the gap δc becomes narrower to the gap δc-a. By doing so, the seal blocks 32A and 32B can be brought into surface contact with the groove bottom wall 25a with pressure, so that leakage from the gap of the cooling air (compressed air a4) can be effectively prevented.

  Further, when the adjacent outer end walls 13A and 13B are displaced differently in the radial direction, and the outer end wall 13B is displaced by a step δr above the paper surface with respect to the outer end wall 13A, for example, as shown in FIG. The seal plate 29A of the seal member 28 is in surface contact with the outer diameter side wall surface of the seal groove 25A of the outer end wall 13A, and the seal plate 29B is in surface contact with the inner diameter side wall surface of the seal groove 25B of the outer end wall 13B. Here, since the two sealing plates 29A and 29B are continuously connected by the leaf springs 30A and 30B and 31A and 31B, the cooling air (compressed air a4) which is about to leak from the outer diameter side of the gap is This can be prevented by leaf springs 30B and 31B connecting the contact surface of the seal plate 29A and the contact surface of the seal plate 29B and the seal plates 29A and 29B. At this time, the interval between the seal plates 29A and 29B and the compression force of the leaf springs 30A, 30B and 31A, 31B are set so that the leaf springs 30A, 30B and 31A, 31B are bent by the step δr. Since the seal plates 29A and 29B can be brought into surface contact with pressure, leakage from the gap of the cooling air (compressed air a4) can be effectively prevented. When the outer end wall 13A deviates from the outer end wall 13B by a step δr above the paper surface, the surface contact positions of the seal plates 29A and 29B are reversed, but the same effect can be achieved.

  By the way, generally, the stationary blade body segment 21 is precision cast with a Ni-based heat-resistant alloy which is a nonmagnetic material. Therefore, by installing the magnetic material 33 on the groove bottom wall 25a of the seal groove 25B on one side of the seal grooves 25A and 25B and setting the seal block 32B with a permanent magnet or the like, the seal block 32B is always provided. Is magnetically attracted to the groove bottom wall 25a. When the seal member 28 is mounted in the seal grooves 25A, 25, the seal member 28 is magnetically held on the groove bottom wall 25a in the seal groove 25B on one side. Thus, since the seal member 28 can be mounted in the seal groove 15A on the other side, the assembling work of the seal member 28 can be easily and accurately performed. When the stationary blade body segment 21 is made of a heat-resistant alloy having magnetism, the magnetic material 33 does not need to be provided on the groove bottom wall 25a.

  Next, the effect | action at the time of operation | movement of the gas turbine equipment 1 in this Embodiment is demonstrated.

  The high-temperature and high-pressure combustion gas G1 generated in the combustor 3 has a pressure of about 1.2 MPa and a temperature of 1200 ° C., and flows into the inlet of the first stage stationary blade 6A in the gas turbine 4. In the following, the first stage rotor blade 7A and the like progress dramatically while reducing the pressure and temperature while converting the fluid energy of the combustion gas into rotational energy, and pass through the final stage rotor blade at about 600 ° C. and exhausted. The

  Since the turbine blades (moving blades and stationary blades) are exposed to the high-temperature combustion gas G1, high-pressure compressed air a3 to a5 obtained by the air compressor 2 is used as cooling air. The cooling air exchanges heat inside the blade, and the temperature is reduced to an allowable temperature of 800 ° C. or less of the Ni-base alloy blade material having high heat resistance. However, each member has a higher temperature than that at normal temperature, and each member is thermally deformed by such a temperature. Therefore, the stationary blade body segment 21 is designed so as to secure a gap δc between the adjacent stationary blade body segments 21 in consideration of circumferential elongation due to thermal deformation, and this gap δc does not contact even during rated operation. ing.

  As the gap δc is reduced from the gap δc due to circumferential elongation to the gap δc-a, the seal block 32B in contact with the groove bottom wall 25a of the seal groove 25B replaces the opposite seal block 32A with the groove bottom wall 25a of the seal groove 25A. When they are displaced to the side and brought into surface contact, and further in the circumferential direction, compression forces by the leaf springs 30A, 30B and 31A, 31B act between the seal blocks 32A, 32B. This compressive force increases the surface contact pressure to the groove bottom wall 25a of the seal blocks 32A and 32B, and increases the radial distance between the seal plates 29A and 29B, thereby making the seal plate 29A a radius of the seal grooves 25A and 25B. The seal plate 29B is pressed against the wall surface on the lower side in the radial direction of the seal grooves 25A and 25B. Therefore, the gap can be closed by surface contact within the seal grooves 25A and 25B of the seal plates 29A and 29B and the seal blocks 32A and 32B.

  On the other hand, when a step δr is generated in the radial direction of the adjacent stationary blade body segment 21 due to the thermal deviation, a step is generated between the opposing seal grooves 25A and 25B. Due to the step between the seal grooves 25A and 25B, the seal plates 29A and 29B are in surface contact with the inner walls in the radial direction of the seal grooves 25A and 25B on the opposite side, as shown in FIG. At this time, the ambient temperature of the seal plates 29A and 29B is about 500 ° C., and the magnetic force of the seal block 32B has disappeared, but the seal blocks 32A and 32B have already been groove bottom walls of the seal grooves 25A and 25B. Since the surface is in contact with 25a, the sealing effect is not lost.

  As described above, the seal member 28 does not incline within the seal grooves 25A and 25B and forms a seal surface by surface contact of each part, despite the occurrence of the step δr in the radial direction of the adjacent stationary blade body segment 21. Therefore, leakage of cooling air from the gap δc-a can be prevented.

  The embodiment described above is the description of the outer end walls 13A and 13B of the adjacent stationary blade body segments 21, but the inner end wall 14 adjacent in the circumferential direction, the shrouds 8A and 8B, the diaphragm 19, and the like are provided with gaps. Needless to say, the present invention can be applied to a divided structure having opposing surfaces facing each other.

The block diagram which shows the gas turbine installation with which the sealing device by this invention is applied. The expanded sectional view which shows a part of gas turbine of FIG. FIG. 3 is an enlarged view around the stationary blade shown in FIG. 2. FIG. 3 is a development view of an adjacent outer end wall. The expanded sectional view which follows the AA line of FIG. FIG. 5 is a view corresponding to FIG. 5 showing a thermal displacement state of the outer end wall.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Gas turbine equipment, 2 ... Air compressor, 3 ... Combustor, 4 ... Gas turbine, 5 ... Generator, 6A ... First stage stationary blade, 6B ... Second stage stationary blade, 7A ... First stage rotor blade 7A, 7B ... Second stage blade, 8A, 8B ... shroud, 9 ... casing, 10 ... rotor, 11A ... first wheel, 11B ... second wheel, 12 ... spacer, 13, 13A, 13B ... outer end wall, 14 ... inner end Wall, 15 ... Wing, 16 ... Cooling air cavity, 17 ... Cavity cover, 18 ... Diaphragm chamber, 19 ... Diaphragm, 20 ... Seal fin, 21 ... Stator body segment, 22 ... Cooling air chamber, 23A, 23B ... Wheel Space, 24A, 24B, 26 ... Opposing surface, 25A, 25B, 27 ... Seal groove, 25a ... Groove bottom wall, 28 ... Seal groove, 29A, 29B ... Le plate, 30A, 30B, 31A, 31B ... leaf spring, 32A, 32B ... seal block, 33 ... magnetic material.

Claims (4)

  A gas turbine facility comprising an air compressor, a combustor, and a gas turbine, wherein the constituent members of the gas turbine are formed of a divided structure having opposing surfaces facing each other through a gap, and the opposed parts of the divided structures A seal groove having a rectangular cross-section formed to face each of the surfaces, a seal member that is mounted across the opposite seal grooves and closes the gap, and a gas on which differential pressure acts on both sides of the seal member In the sealing device for turbine equipment, the seal member includes two seal plates that are separated in a direction in which the differential pressure acts, and an elastic body that connects the two seal plates, and the two seals A sealing device for a gas turbine facility, wherein one of the plates is brought into surface contact with a wall surface in a sealing groove using the differential pressure.   A gas turbine facility comprising an air compressor, a combustor, and a gas turbine, wherein the constituent members of the gas turbine are formed of a divided structure having opposing surfaces facing each other through a gap, and the opposed parts of the divided structures A seal groove having a rectangular cross-section formed to face each of the surfaces, a seal member that is mounted across the opposite seal grooves and closes the gap, and a gas on which differential pressure acts on both sides of the seal member In the sealing device for turbine equipment, the seal member includes two seal plates that are separated in a direction in which the differential pressure acts, and an elastic body that connects the two seal plates, and the two seals A structure is provided in which one of the plates is brought into surface contact with the wall surface in the seal groove using the differential pressure, and in contact with the groove bottom wall of each of the seal grooves when the divided structure is thermally expanded. Sea Sealing apparatus for a gas turbine equipment, characterized in that a member on the seal plate.   The gas turbine equipment sealing device according to claim 2, wherein, when the divided structure is formed of a magnetic material, at least one of the second sealing members is formed of a permanent magnet.   When the divided structure is formed of a nonmagnetic material, at least one of the second seal members is formed of a permanent magnet, and a magnetic material is applied to the groove bottom wall of the seal groove facing the permanent magnet. The sealing device for gas turbine equipment according to claim 2, wherein the sealing device is provided.

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