JP4598583B2 - Steam turbine seal equipment - Google Patents

Description

  The present invention relates to a steam turbine seal device that reduces steam leakage between a nozzle diaphragm inner ring side of a steam turbine and a rotor outer peripheral portion.

  In a conventional steam turbine seal device, a plurality of seal fins are provided on the stationary part side, and the seal fins are arranged facing the rotor surface at a radial interval, and the seal fin faces the rotor surface portion facing the seal fin. An uneven portion is formed, and the seal fin length is changed in accordance with the uneven portion. This is called a high / low type labyrinth seal device, where the radial gap between the seal fin and the rotor concavo-convex portion is set as small as possible, or a large number of seal fins are provided to increase the steam passage distance. By doing so, the steam leakage loss is reduced and the turbine efficiency is thereby improved.

  There is also an embedded sealing technique called caulking seal. In this method, a plurality of grooves are provided at a predetermined interval in a stationary part or a rotating part, and seal fins are caulked and fixed in these grooves, and there are a staggered type and a double strip type as a caulking seal. In the staggered type, the seal fins on the stationary part side and the seal fins on the rotating part side are shifted in the axial direction of the rotor and arranged in an overlapping manner. The double strip type is a seal fin on the stationary part side and the rotating part. The side seal fins are arranged with a constant gap in the radial direction. Such a caulking seal has an advantage that excessive shaft vibration (rubbing vibration) due to thermal deformation of the rotor hardly occurs because the seal fin itself is extremely thin and has good heat dissipation.

  In addition, seal fins are provided on each of the stationary part and the rotating part to improve the sealing performance of the sealing device in which the stationary part side sealing fins and the rotating part side seal fins are shifted in the rotor axial direction and arranged alternately. As a technique for doing this, there is a sealing device described in Japanese Patent Laid-Open No. 2003-201806. This is a seal fin provided on the stationary blade diaphragm outer ring on the stationary part side, and a plurality of protruding plates are provided in the circumferential direction, causing fluid to collide with the protruding plate, generating a separation vortex, and rotating with the seal fin The fluid leakage is reduced by increasing the flow pressure loss of the fluid flowing through the gap with the rotor blade shroud, which is the part side.

JP 2003-201806 A

  In the conventional high / low type labyrinth seal device, when there is a large temperature difference between the turbine non-operation and the steady operation, a difference between the thermal expansion amount in the stationary portion and the thermal expansion amount in the rotating portion occurs. There is a possibility that a part on the circumference of the rotor is deformed into a convex shape due to the temperature rise and thermal expansion at the contact portion. In this case, the contact is further strengthened, and the local thermal elongation of the rotor is enlarged, and finally an excessive shaft vibration called rubbing vibration is generated. When rubbing vibration occurs, the operation of the turbine must be stopped, and in the worst case, there is a problem that the turbine rotor is deformed due to distortion caused by thermal stress at the contact portion.

  In the staggered type caulking seal device, when the seal fin on the rotating part side contacts the stationary part, the temperature of the seal fin rises temporarily, but the seal fin itself is extremely thin and the rotor itself rotates at high speed. Therefore, the seal fin is cooled by the flow of steam, and heat input into the rotor is kept low. For this reason, there is no thermal elongation or rubbing vibration caused by local heat input to the rotor, as seen in high-low labyrinth seal devices. However, if the clearance between the seal fin on the rotating part side and the rotor is made too small, contact between the seal fin and the rotor will occur, and the thermal expansion or the like due to the local heat input to the rotor as described above will occur. There was a problem that rubbing vibration occurred.

  Also, in the staggered type caulking seal device, when the seal fins come into contact with each other due to the difference in thermal expansion between the stationary part and the rotating part in the rotor axial direction, the seal fins themselves are deformed and the seal gap is widened to improve the sealing performance. There was also a problem of deterioration.

  In the double strip type caulking seal device, even when a deviation in the rotor axial direction occurs due to a difference in thermal elongation between the stationary portion and the rotating portion, there is no possibility that the seal fins contact each other. However, in the double strip type, the sealing performance is high if the axial distance between the opposing seal fins is always kept constant, but the stationary part and the rotor (rotation) are required before the steam turbine starts operation and enters steady operation. Temperature difference between the two parts), and thus a thermal expansion difference also occurs in the axial direction. When a change occurs in the axial interval between the seal fins, this sealing device has a problem in that the sealing performance is greatly deteriorated.

  The sealing device described in Japanese Patent Laid-Open No. 2003-201806 reduces fluid leakage by causing a fluid to collide with a protruding plate provided on a seal fin to generate a separation vortex and increasing fluid flow pressure loss. . However, in the configuration of this sealing device, as in the case of the staggered type caulking sealing device, there is a possibility that the seal fins come into contact with each other due to the difference in thermal expansion between the stationary portion and the rotating portion in the rotor axial direction. There is a problem that the fin breaks and leads to an accident.

  An object of the present invention is to avoid contact between a seal fin and a rotor or seal fins in a steam turbine seal device provided in the vicinity of a turbine rotor in order to prevent steam leakage, thereby preventing rubbing vibration and deformation of the seal fins. The present invention also provides a steam turbine seal device that can reduce the steam leakage loss due to the difference in thermal elongation between the stationary part and the rotating part in the rotor axial direction and improve the sealing performance.

  In order to solve the above object, the present invention adopts the following configuration.

First, the first aspect of the present invention provides a steam turbine seal device disposed on the nozzle diaphragm inner ring side and the rotor outer peripheral portion in order to reduce steam leakage from between the nozzle diaphragm inner ring side and the rotor outer peripheral portion of the steam turbine. A plurality of first seal fins projecting radially in the nozzle diaphragm inner ring side, and a plurality of second seal fins projecting radially in the outer periphery of the rotor are provided, and the plurality of second seal fins The rotor causes a flow in the direction of the rotor rotation axis to form a structure that prevents a flow leaking between the first seal fin and the second seal fin. Regarding the two opposing surfaces of the second seal fin, the surface on the upstream side has a finer surface roughness than the surface on the downstream side .

A second aspect of the present invention is a steam turbine seal device disposed on the nozzle diaphragm inner ring side and the rotor outer peripheral part in order to reduce steam leakage from between the nozzle diaphragm inner ring side of the steam turbine and the rotor outer peripheral part. A plurality of first seal fins projecting radially in the nozzle diaphragm inner ring side, and projecting radially in the outer peripheral portion of the rotor with a gap in the radial direction with respect to the plurality of first seal fins. And a plurality of second seal fins are provided, and the plurality of second seal fins are caused to flow in the rotor rotation axis direction by rotation of the rotor, and between the first seal fins and the second seal fins. Forming a structure that obstructs the flow that leaks out of the second seal fin, and the structure is disposed downstream of the two opposing surfaces of the second seal fin. Towards the upstream side of the surface from the surface it is to finely configuration surface roughness.

  Further, the second seal fin preferably has a plurality of grooves provided at predetermined intervals in the rotor, and a plurality of second seal fins on which the structure is formed are caulked and fixed in the plurality of grooves. It is. Further, the second seal fin may be formed by cutting a plurality of second seal fins from a rotor, and further creating the structure by cutting out the plurality of second seal fins. .

  According to the present invention, the following effects can be obtained.

  (1) Steam leakage loss due to the difference in thermal expansion in the rotor axial direction between the stationary part (nozzle diaphragm inner ring side) and the rotating part (rotor side) can be reduced, and the sealing performance can be improved. As a result, the turbine efficiency can be improved.

  (2) Contact between the seal fin and the rotor or the seal fin can be avoided, and generation of rubbing vibration and deformation of the seal fin can be prevented.

  (3) The steam leakage loss due to the difference in thermal elongation between the stationary part and the rotating part in the rotor axial direction, which is a weak point of the double strip type, can be reduced, the sealing performance can be improved, and as a result, the turbine efficiency can be improved.

  (4) Since the sealing performance per sealing device is improved, the number of sealing devices arranged along the rotor rotation axis direction can be reduced.

  (5) Since the number of sealing devices can be reduced, the rotor shaft length and the casing portion axial length can be shortened.

  (6) Since the number of sealing devices can be reduced and the length of the rotor shaft and the casing portion in the axial direction can be shortened, material costs and processing costs associated with the manufacture of the rotor and casing can be reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  First, in order to facilitate understanding of the present invention, a conventional technique and its problems will be described with reference to the drawings.

  FIG. 13 is a configuration diagram of the steam turbine. In FIG. 13, 101 is a turbine rotor, 102 is a moving blade, 103 is an inner casing, 104a is a nozzle diaphragm inner ring side, 104b is a nozzle diaphragm outer ring side, and 105 is a stationary blade. In the steam turbine, the moving blades 102 arranged in the circumferential direction of the turbine rotor 101 and the stationary blades 105 provided in the inner casing 103 via the nozzle diaphragm outer ring side 104b are alternately arranged. And a plurality of stages of turbine stages formed by one row of stationary blades. Then, after the steam drawn into the turbine is expanded and speeded up by the stationary blade 105, the steam is caused to flow into the rotor blade 102, thereby rotating the turbine rotor 101.

  A gap is provided between the turbine rotor 101 and the nozzle diaphragm inner ring side 104 a of the stationary blade 105 to allow the rotational movement of the turbine rotor 101. This gap prevents leakage of steam flowing into the stationary blade 105. It was also a cause. Since such a leak causes a decrease in turbine efficiency, a portion for preventing a steam leak called a seal device is provided in the vicinity of the turbine rotor on the nozzle diaphragm inner ring side 104a of the stationary blade 105.

  FIG. 14 is a configuration diagram showing a typical example of a conventional sealing device, and is a diagram showing a high-low labyrinth sealing device. In FIG. 14, a nozzle stationary diaphragm 106 having a plurality of seal fins 107 is fitted and fixed to the nozzle diaphragm inner ring side 104 a, and a plurality of convex portions 108 are formed on the outer peripheral portion of the rotor 101. The seal fins 107 are disposed to face the rotor protrusion 108 and the bottom surface of the concave portion therebetween with a radial interval therebetween. Such a seal device having a non-contact structure with the turbine rotor 101 is called a labyrinth seal, and is a seal device that has been widely used in steam turbines (hereinafter referred to as Conventional Technology 1). In this prior art 1, the gap between each seal fin 107 and the turbine rotor 101 is set to be as small as possible, or a large number of seal fins 107 are provided to increase the steam passage distance. The amount of steam leaking from the gap between the rotors 101 is reduced to reduce steam leakage loss and thereby improve turbine efficiency.

  However, in the prior art 1, when there is a large temperature difference between when the turbine is not operating and during steady operation, a difference between the thermal expansion amount at the stationary portion and the thermal expansion amount at the rotating portion occurs, so the rotor protrusion 108 and the seal fin 107 may overlap in the flow direction and come into contact with each other. When the rotor protrusion 108 and the seal fin 107 come into contact with each other, a part of the circumference of the rotor 101 is deformed into a convex shape due to temperature rise and thermal expansion at the turbine rotor contact portion. In this case, the contact is further strengthened and the local thermal elongation of the rotor 101 is enlarged, and finally an excessive shaft vibration called rubbing vibration is generated. When rubbing vibration occurs, the operation of the turbine must be stopped, and in the worst case, there is a problem that the turbine rotor 101 is deformed due to distortion due to thermal stress at the contact portion.

  As a solution to such a problem, there is a rotor embedded seal technology called a caulking seal. The caulking seal is roughly classified into a staggered type caulking seal (hereinafter referred to as Conventional Technology 2) and a double strip type caulking seal (hereinafter referred to as Conventional Technology 3).

  FIG. 15 shows a typical example of the prior art 2. In the prior art 2, a groove is provided at a predetermined interval in the seal stationary body 106 on the inner side of the nozzle diaphragm, and the seal fin 107A is caulked and fixed in this groove, and a groove is also provided in the rotor 101 at a predetermined interval. The seal fins 109 are caulked and fixed, and the seal fins 107A and the seal fins 109 are displaced in the axial direction of the rotor and arranged so as to alternately overlap.

  In this sealing device, when the seal fin 109 embedded in the turbine rotor 101 and the seal stationary body 106 come into contact with each other, the temperature of the seal fin 109 temporarily rises. However, since the seal fin itself is extremely thin and the turbine rotor 101 itself rotates at high speed, the seal fin 109 is cooled by the flow of steam, and heat input into the turbine rotor 101 is kept low. Therefore, there is no thermal elongation or rubbing vibration caused by local heat input to the rotor 101 as seen in the prior art 1.

  However, in the prior art 2, when the seal fin 107A and the seal fin 109 come into contact with each other due to the difference in thermal expansion between the stationary portion and the rotating portion in the axial direction, the seal fin itself is deformed, and the seal gap is widened to deteriorate the seal performance. Resulting in. Also, if the gap between the seal fin 107A and the turbine rotor 101 is made too small, contact between the seal fin 107A and the rotor 101 will occur, and local heat input to the rotor 101 as seen in the prior art 1 will occur. There was a problem that heat elongation by rubbing and rubbing vibration occurred.

  Conventional technique 3 has been proposed to solve such a problem. FIG. 16 shows a representative example of the prior art 3. In the prior art 3, grooves are provided in the seal stationary body 106 on the inner side of the nozzle diaphragm at predetermined intervals, and the seal fins 107A are caulked and fixed in the grooves, and grooves are also provided in the rotor 101 at predetermined intervals. The seal fin 109 is caulked and fixed, and the seal fin 107A and the seal fin 109 are arranged with a certain gap in the radial direction. In the illustrated example, the pitch interval is different between the seal fin 107 </ b> A and the seal fin 109.

  In this sealing device, even if a shift in the axial direction occurs due to a difference in thermal expansion between the stationary part and the rotating part, there is no possibility that the seal fins come into contact with each other, and the number of seal fins may be increased to further improve the sealing performance. Is possible.

  In the prior art 3, the sealing performance is high if the axial distance between the opposing seal fins 107A and 109 is always kept constant. However, there is a temperature difference between the casing (stationary part) and the rotor 101 (rotating part) before the steam turbine enters the steady operation from the start, so that a difference in thermal expansion also occurs in the axial direction. When a change occurs in the axial interval between the seal fins, this sealing device has a problem in that the sealing performance is greatly deteriorated. There is also a method of arranging a large number of seal fins in order to compensate for the performance degradation due to the difference in axial thermal expansion. However, when the number of seal fins exceeds a certain number, blow-through occurs, so that there is a limit to the number of seal fins to be arranged. This blow-through is the kinetic energy of the fluid that passes through the expansion chamber and flows into the next expansion chamber without completely dissipating the heat energy through one seal fin, that is, the kinetic energy carry-over phenomenon to the next stage. That means. This increase in the blow-through deteriorates the sealing performance.

  The present invention solves the above-described problems.

FIG. 1 shows a configuration diagram of a steam turbine provided with a steam turbine seal device according to a first embodiment of the present invention. In FIG. 1, 1 is a rotor, 2 is a moving blade, 3 is an inner casing, 4a is a nozzle diaphragm inner ring side, 4b is a nozzle diaphragm outer ring side, 5 is a stationary blade, 10 is an outer casing, and 11 is a steam inlet portion. .
In the steam turbine, the moving blades 2 arranged in the circumferential direction of the turbine rotor 1 and the stationary blades 5 provided in the inner casing 3 via the nozzle diaphragm outer ring side 4b are alternately arranged. And a plurality of stages of turbine stages formed by one row of stationary blades. Then, the steam drawn into the turbine is expanded and speeded up by the stationary blade 5, and then flows into the moving blade 2 portion, thereby rotating the turbine rotor 1.

  FIG. 2 is a detailed view of the A-A portion of FIG. 1 and shows the configuration of the sealing device in the first embodiment of the present invention. In the figure, the present invention is applied to a double strip type caulking seal device.

  In FIG. 2, a plurality of grooves are provided at predetermined intervals in the seal stationary body 6 on the inner side of the nozzle diaphragm, and a plurality of seal fins 7 are caulked and fixed to the plurality of grooves, and a plurality of grooves are also fixed to the rotor 1 at predetermined intervals. Grooves are provided, and a plurality of seal fins 9 are caulked and fixed in the plurality of grooves, and the seal fins 7 and the seal fins 9 are arranged with a constant gap in the radial direction. In the illustrated example, the plurality of seal fins 7 and the plurality of seal fins 9 have different pitch intervals in the rotor axial direction.

  On the surface of the seal fin 9 on the rotor 1 side, uneven portions 12 extending in the radial direction are formed discretely at predetermined intervals in the circumferential direction. The optimum number of the concavo-convex portions 12 is the leakage speed and the interval between the seal fins 9 (interval in the rotor axial direction), the gap between the seal fins 7 and the seal fin 9 (interval in the rotor axial direction and radial direction), and the turbine rotor. It is determined from the number of revolutions of 1. What is important here is that the concave and convex portions 12 are discretely installed in the circumferential direction. The uneven portion 12 only needs to have a structure that induces a speed component that disturbs the blow-by flow and a speed component that is radially outward with respect to the rotation axis of the turbine rotor 1. In the drawing, 13 indicates the steam flow direction in the turbine, and 14 indicates the rotation direction of the turbine rotor 1.

  3 is a detailed view of the seal fin on the rotor 1 side shown in FIG. In this embodiment, the surface on one side of the seal fin 9 embedded in the surface of the turbine rotor 1 is perpendicular to the rotational direction 14 of the turbine rotor 1, that is, radially (in the radial direction) with a predetermined interval. A plurality of concave portions 15a and convex portions 15b are alternately formed. The concave portion 15 a and the convex portion 15 b are a convex portion and a concave portion on the surface on the opposite side of the seal fin 9, and constitute the concave and convex portion 12. As a result, the surface on the opposite side of the seal fin 9 has a configuration in which concave portions and convex portions are alternately formed in a radial pattern.

  In the concave portion 15a and the convex portion 15b formed as described above, when the turbine rotor 1 rotates, the fluid in the outer peripheral portion of the turbine rotor 1 is caused by the slopes (inclined portions) 16 of the concave portion 15a and the convex portion 15b. A flow 17 is induced in the concave surface portion of the concave portion 15a and the convex surface portion of the convex portion 15b to form a flow component radially outward with respect to the rotation axis. The outward radial component 17 along the concave portion and the convex portion reduces the blow-through speed of the seal structure constituted by the turbine rotor 1, the seal stationary body 6, and the seal fins 7 and 9. As a result, the sealing performance is improved. The effect of improving is produced.

  FIG. 4 is a schematic diagram of streamlines of the sealing device according to the present embodiment. By providing the turbine rotor 1 with the seal fin 9 having the concave and convex portions 12 (the concave portions 15a and the convex portions 15b) shown in FIG. 3, a flow component 17 radially outward with respect to the rotor rotation shaft is formed. The radially outward flow 17 turns the leakage flow 18 generated by the static pressure ratio P1 / P2 around the seal fin 7 outward in the radial direction. Compared with the conventional leak flow 18, the leak flow 19 generated thereby collides with the seal fin 7b on the downstream side, and a larger flow rate is formed by the seal fins 7, 7b, 9, 9b. The kinetic energy of the flow can be dissipated into thermal energy.

  Therefore, according to the present embodiment, the leakage flow 18 is diverted radially outward to generate a three-dimensional and unsteady vortex having a large kinetic energy dissipation effect in the expansion chamber 20. Blow-out due to thermal expansion difference in the rotor axial direction between the stationary part (nozzle diaphragm inner ring side) and the rotating part (rotor side), which is a weak point of the double strip type in which the fin 7 and the seal fin 9 are arranged with a certain gap in the radial direction. The amount (steam leakage loss) can be greatly reduced, and the sealing performance can be improved. Further, according to the present embodiment, since the blow-by can be reduced without changing the seal fin interval, the sealing performance can be further improved.

  Further, since the seal fin 7 and the seal fin 9 are of a double strip type in which a certain gap is provided in the radial direction, the contact between the seal fin and the rotor or the seal fin is surely avoided, the occurrence of rubbing vibration and the seal The deformation of the fin can be prevented.

  In addition, since the sealing performance per sealing device is improved, the number of sealing devices arranged along the rotor rotation axis direction can be reduced. Moreover, since the number of sealing devices can be reduced, the rotor shaft length and the casing axial direction length can be shortened, and as a result, material costs and processing costs associated with the manufacture of the rotor and casing can be reduced.

  FIG. 5 is a view showing details of the seal fins of the steam turbine seal device according to the second embodiment of the present invention. The illustrated one is also one in which the present invention is applied to a double strip type caulking seal device. In the following description, members equivalent to those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the present embodiment, the surface on one side (upstream side in the illustrated example) of the seal fin 9 embedded in the surface of the turbine rotor 1 has a plurality of blade shapes curved from the radius of the turbine rotor 1 to the circumferential direction. The wing portion 21 is formed at a predetermined interval.

  In the blade portion 21 formed as described above, the turbine rotor 1 rotates, and the fluid in the outer peripheral portion of the turbine rotor 1 is induced as a flow 17 along the blade shape of the blade portion 21 and rotates. A flow component is formed radially outward with respect to the shaft. The radially outward flow component 17 along the blade shape reduces the blow-through speed of the seal structure composed of the turbine rotor 1, the seal stationary body 6, and the seal fins 7 and 9, thereby improving the sealing performance. The effect of being played.

  FIG. 6 is a schematic diagram of streamlines of the sealing device according to the present embodiment. By providing the turbine rotor 1 with the seal fins 9 that count the blade portions 21 shown in FIG. 5, a flow component 17 that is radially outward with respect to the rotor rotation axis is formed. The radially outward flow 17 turns the leakage flow 18 generated by the static pressure ratio P1 / P2 around the seal fin 7 outward in the radial direction. Compared with the conventional leak flow 18, the leak flow 19 generated thereby collides with the seal fin 7b on the downstream side, and a larger flow rate is formed by the seal fins 7, 7b, 9, 9b. The kinetic energy of the flow can be dissipated into thermal energy.

  Therefore, according to the present embodiment, the leakage flow 18 is diverted radially outward to generate a three-dimensional and unsteady vortex having a large kinetic energy dissipation effect in the expansion chamber 20. Blow-out due to thermal expansion difference in the rotor axial direction between the stationary part (nozzle diaphragm inner ring side) and the rotating part (rotor side), which is a weak point of the double strip type in which the fin 7 and the seal fin 9 are arranged with a certain gap in the radial direction. The amount (steam leakage loss) can be greatly reduced, and the sealing performance can be improved. Further, according to the present embodiment, since the blow-through can be reduced without changing the seal fin interval, the sealing performance can be further improved.

  In addition, the same effects as those of the first embodiment can be obtained, for example, the contact between the seal fin and the rotor or the seal fin can be reliably avoided, and the occurrence of rubbing vibration and the deformation of the seal fin can be prevented.

  FIG. 7 is a view showing details of the seal fins of the steam turbine seal device according to the third embodiment of the present invention. The illustrated one is also one in which the present invention is applied to a double strip type caulking seal device. In the following description, members equivalent to those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In this embodiment, the surface on one side (upstream side in the illustrated example) of the seal fin 9 embedded in the surface of the turbine rotor 1 is perpendicular to the rotational direction 14 of the turbine rotor 1, that is, radially (radius) (Direction), the groove portion 22 is formed. In the present embodiment, the groove 22 is formed by stamping a seal fin material. As a result, radial convex portions 22 a extending in the radial direction are formed at positions corresponding to the groove portions 22 on the surface on the opposite side of the seal fin 9.

  In the groove portion 22 formed as described above, when the turbine rotor 1 rotates, the fluid in the outer peripheral portion of the turbine rotor 1 is guided as a flow 17 inside the groove by the slope (inclined portion) 16 of the groove portion 22. A flow component radially outward with respect to the rotation axis is formed. The radially outward flow component 17 along the groove interior reduces the blow-through speed of the seal structure composed of the turbine rotor 1, the seal stationary body 6, and the seal fins 7 and 9, thereby improving the seal performance. The effect of being played. The same applies to the convex portion 22a formed on the surface on the opposite side of the seal fin 9.

  FIG. 8 is a schematic diagram of streamlines of the sealing device according to the present embodiment. By providing the turbine rotor 1 with the seal fin 9 formed with the groove portion 22 and the convex portion 22a shown in FIG. 7, a flow component 17 radially outward with respect to the rotor rotation shaft is formed. The radially outward flow 17 turns the leakage flow 18 generated by the static pressure ratio P1 / P2 around the seal fin 7 outward in the radial direction. Compared with the conventional leak flow 18, the leak flow 19 generated thereby collides with the seal fin 7b on the downstream side, and a larger flow rate is formed by the seal fins 7, 7b, 9, 9b. The kinetic energy of the flow can be dissipated into thermal energy.

  Therefore, according to the present embodiment, the leakage flow 18 is diverted radially outward to generate a three-dimensional and unsteady vortex having a large kinetic energy dissipation effect in the expansion chamber 20. Blow-out due to thermal expansion difference between the stationary part (nozzle diaphragm inner ring side) and the rotating part (rotor side) in the rotor axial direction, which is a weak point of the double strip type in which the fins 7 and the seal fins 9 are arranged with a constant gap in the radial direction. The amount (steam leakage loss) can be greatly reduced, and the sealing performance can be improved. Further, according to the present embodiment, since the blow-through can be reduced without changing the seal fin interval, the sealing performance can be further improved.

  In addition, the same effects as those of the first embodiment can be obtained, for example, the contact between the seal fin and the rotor or the seal fin can be reliably avoided, and the occurrence of rubbing vibration and the deformation of the seal fin can be prevented.

  FIG. 9 is a diagram showing details of the seal fins of the steam turbine seal device in the fourth embodiment of the present invention. The illustrated one is also one in which the present invention is applied to a double strip type caulking seal device. In the following description, members equivalent to those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the present embodiment, radial grooves 22 extending in the radial direction are provided on the surface 23 a on one side (upstream side in the illustrated example) of the seal fin 9 embedded in the surface of the turbine rotor 1, and the opposite side of the seal fin 9 is provided. Radial convex portions 22a extending in the radial direction are formed at positions corresponding to the groove portions 22 on the surface 23b. Further, the surface roughness of the seal fin 9 is such that the surface roughness of the surface 23a of the seal fin 9 located on the upstream side with respect to the steam flow leaking through the radial gap between the seal fins 7 and 9 is on the downstream side. It is configured to be finer with respect to the surface roughness of the surface 23b of the seal fin 9 positioned. That is, the upstream surface 23a of the seal fin 9 is a seal fin surface subjected to fine surface processing, and the downstream (opposite side) surface 23b is a seal fin surface subjected to rough surface processing.

  In the configuration in which the surface roughness is different from that of the groove 22 and the convex portion 22a formed as described above, when the turbine rotor 1 rotates, the fluid in the outer peripheral portion of the turbine rotor 1 is guided as the flow 17 to rotate. A flow component is formed radially outward with respect to the shaft. In addition, the flow velocity of the downstream surface 23b having a large surface roughness is larger than that of the upstream surface 23a having a small surface roughness. This difference in the outward flow velocity in the radial direction is induced as a flow in a direction opposite to the blow-through flow of the seal structure constituted by the turbine rotor 1, the seal stationary body 6, and the seal fins 7 and 9, and as a result, the flow There is an effect that the sealing performance is improved by reducing the speed.

  FIG. 10 is a schematic diagram of streamlines of the sealing device according to the present embodiment. By providing the turbine rotor 1 with seal fins 9 having different surface roughnesses of the groove 22 and the surfaces 23a and 23b shown in FIG. 9, flow components 24a and 24b radially outward with respect to the rotor rotation shaft are formed. Is done. The radially outward flows 24a and 24b generate an axial flow 25 in the opposite direction to the leakage flow 18 generated by the static pressure ratio P1 / P2 before and after the seal fin 7. As a result, a larger flow rate stays in the expansion chamber 20 formed by the seal fins 7, 7b, 9, 9b, and the kinetic energy of the flow can be dissipated into thermal energy.

  Therefore, according to the present embodiment, the flow is diverted to the opposite side in the axial direction with respect to the leakage flow 18, so that the seal fin 7 and the seal fin 9 are arranged with a constant gap in the radial direction. The amount of blow-through (steam leakage loss) due to the difference in thermal elongation between the stationary part (nozzle diaphragm inner ring side) and the rotating part (rotor side), which are weak points, can be greatly reduced, and the sealing performance can be improved. . Further, according to the present embodiment, since the blow-through can be reduced without changing the seal fin interval, the sealing performance can be further improved.

  In addition, the same effects as those of the first embodiment can be obtained, for example, the contact between the seal fin and the rotor or the seal fin can be reliably avoided, and the occurrence of rubbing vibration and the deformation of the seal fin can be prevented.

  FIG. 11 is a view showing details of seal fins of a steam turbine seal device according to a fifth embodiment of the present invention. The illustrated one is also one in which the present invention is applied to a double strip type caulking seal device. In the following description, members equivalent to those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In this embodiment, a plurality of radial notches 26 are provided radially on the seal fin 9 embedded in the surface of the turbine rotor 1, and one or both of the opposite edges of the notches 26 are provided on the rotor. It has a configuration in which it is spread in the axial direction and has a gap therebetween.

  In the seal fin 9 formed as described above, when the turbine rotor 1 rotates, a flow in a direction opposite to the blow-through flow of the seal structure including the turbine rotor 1, the seal stationary body 6, and the seal fins 7 and 9 is generated. As a result, the flow velocity is reduced and the sealing performance is improved.

  FIG. 12 is a schematic diagram of streamlines of the sealing device according to the present embodiment. When the turbine rotor 1 is provided with the seal fin 9 having the notch portion 26 shown in FIG. The flow 25 on the opposite side in the axial direction is generated. As a result, a larger flow rate remains in the expansion chamber 20 formed by the seal fins 7, 7b, 9, 9b, and the kinetic energy of the flow can be dissipated into thermal energy.

  Therefore, according to the present embodiment, the flow is diverted to the opposite side in the axial direction with respect to the leakage flow 18, so that the seal fin 7 and the seal fin 9 are arranged with a constant gap in the radial direction. The amount of blow-through (steam leakage loss) due to the difference in thermal elongation between the stationary part (nozzle diaphragm inner ring side) and the rotating part (rotor side), which are weak points, can be greatly reduced, and the sealing performance can be improved. . Further, according to the present embodiment, since the blow-through can be reduced without changing the seal fin interval, the sealing performance can be further improved.

  In addition, the same effects as those of the first embodiment can be obtained, for example, the contact between the seal fin and the rotor or the seal fin can be reliably avoided, and the occurrence of rubbing vibration and the deformation of the seal fin can be prevented.

  In the above embodiment, the present invention is applied to a double strip type sealing device in which the seal fin 7 and the seal fin 9 are arranged with a constant gap in the radial direction. The present invention may be applied to a staggered seal device in which the seal fins and the seal fins on the rotating part side are shifted in the rotor axial direction and are alternately arranged. Also in this case, the seal fins on the rotating part side are configured as in the first to fifth embodiments, and the rotation of the rotor causes a flow outward in the radial direction of the rotor or a flow in the rotor rotation axis direction. By preventing the leaking flow, the steam leakage loss due to the thermal expansion difference in the rotor axial direction between the stationary part (nozzle diaphragm inner ring side) and the rotating part (rotor side) can be reduced, and the sealing performance can be improved. In addition, since the sealing performance can be improved in this way, the gap between the seal fin and the rotor or the gap between the seal fins can be made longer than the conventional distance, and thereby the contact between the seal fin and the rotor or the seal fin can be made. This can avoid rubbing vibration and deformation of the seal fin.

It is a figure which shows the structure of the steam turbine provided with the sealing device of this invention. It is a figure which shows the structure of the sealing device in 1st Example of this invention. It is detail drawing of the seal fin by the side of a rotor. It is a schematic diagram of the streamline of the sealing device by 1st Example of this invention. It is a figure which shows the detail of the seal fin of the steam turbine seal apparatus in the 2nd Example of this invention. It is a schematic diagram of the streamline of the sealing device by 2nd Example of this invention. It is a figure which shows the detail of the seal fin of the steam turbine seal apparatus in the 3rd Example of this invention. It is a schematic diagram of the streamline of the sealing device by 3rd Example of this invention. It is a figure which shows the detail of the seal fin of the steam turbine seal apparatus in the 4th Example of this invention. It is a schematic diagram of the streamline of the sealing apparatus by the 4th Example of this invention. It is a figure which shows the detail of the seal fin of the steam turbine seal apparatus in the 5th Example of this invention. It is a schematic diagram of the streamline of the sealing device by 5th Example of this invention. It is a figure which shows the structure of the conventional steam turbine. It is a figure which shows the conventional sealing device, and a high / low type labyrinth sealing device. It is a figure which shows the conventional other sealing apparatus and is a staggered type caulking sealing apparatus. It is a figure which shows another conventional sealing apparatus, and is a double strip type caulking sealing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rotor 2 ... Moving blade 3 ... Inner casing 4a ... Nozzle diaphragm inner ring side 4b ... Nozzle diaphragm outer ring side 5 ... Stator blade 6 ... Seal stationary body 7 ... Seal fin 9 ... Seal fin 10 ... Outer casing 11 ... Steam inlet part 12 ... seal fin uneven part 13 ... steam flow direction 14 ... turbine rotor rotation direction 15a ... seal fin concave part 15b ... seal fin convex part 16 ... slope 17 ... radial outward flow 18 ... blow-off flow 19 ... leak flow 20 ... expansion chamber 21 ... Wings 22 ... Grooves 23a ... Fine surface processed seal fin surfaces 23b ... Rough surface processed seal fin surfaces 24a and 24b ... Radially outward flow 25 ... Axial flow direction flow 26 ... Seal fin notch 27 ... Axial flow direction flow

Claims (4)

In order to reduce steam leakage from between the nozzle diaphragm inner ring side of the steam turbine and the outer periphery of the rotor, in the steam turbine seal device disposed on the nozzle diaphragm inner ring side and the rotor outer periphery,
Providing a plurality of first seal fins projecting radially on the nozzle diaphragm inner ring side, and providing a plurality of second seal fins projecting radially on the outer periphery of the rotor;
A structure is formed in the plurality of second seal fins to cause a flow in a rotor rotation axis direction by rotation of the rotor and to prevent a flow leaking between the first seal fin and the second seal fin. And
The steam turbine seal device according to claim 1, wherein the structure has a configuration in which the surface on the upstream side of the two opposite surfaces of the second seal fin has a finer surface roughness than the surface on the downstream side. In order to reduce steam leakage from between the nozzle diaphragm inner ring side of the steam turbine and the outer periphery of the rotor, in the steam turbine seal device disposed on the nozzle diaphragm inner ring side and the rotor outer periphery,
A plurality of first seal fins projecting in the radial direction are provided on the inner side of the nozzle diaphragm, and the rotor outer peripheral portion projects in a radial direction and is positioned with a gap in the radial direction with respect to the plurality of first seal fins. Providing a plurality of second seal fins,
A structure is formed in the plurality of second seal fins to cause a flow in a rotor rotation axis direction by rotation of the rotor and to prevent a flow leaking between the first seal fin and the second seal fin. And
The steam turbine seal device according to claim 1, wherein the structure has a configuration in which the surface on the upstream side of the two opposite surfaces of the second seal fin has a finer surface roughness than the surface on the downstream side. 3. The steam turbine seal device according to claim 1, wherein a plurality of grooves are provided in the rotor at predetermined intervals, and a plurality of second seal fins on which the structure is formed are caulked and fixed in the plurality of grooves. A steam turbine seal device characterized by that. 3. The steam turbine seal device according to claim 1 or 2 , wherein the plurality of second seal fins are formed by cutting out from a rotor, and the structure is created by cutting out the plurality of second seal fins. A steam turbine seal device.

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