JP2013185494A - Steam turbine including steam sealing function and moisture removing function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the leakage of effective steam, and to remove moisture in a steam turbine to improve internal efficiency.SOLUTION: A steam turbine 1 includes a plurality of moving vanes 20 arranged while vane tops thereof are made close to the inner peripheral surface of a turbine casing 10, and a plurality of stator vanes 30 held at the inner peripheral side of the turbine casing 10 so as to be adjacent to the moving vanes 20. The steam turbine further includes: an in-vane space 33 which is formed in the stator vane 30, and to which high-pressure steam 61 at a pressure higher than steam 60 flowing to the outside of the stator vane 30 is supplied; a circulation path 11 which communicates with the in-vane space 33 and to which the high-pressure steam 61 is supplied from the in-vane space 33; and one or a plurality of sealing steam introduction and ejection parts 70 which communicate with the circulation path 11 and are formed in the turbine casing 10 in the vicinity of the moving vane 20 in such a way that an ejection opening 71 faces a gap 40 between the vane top of the moving vane 20 and the turbine casing 10, and which ejects the high-pressure steam 61 supplied from the in-vane space 33 via the circulation path 11 from the ejection opening 71.

Description

  The present invention relates to a steam turbine that achieves both steam sealing of a moving blade and moisture removal of a stationary blade.

  In a steam turbine, there is a demand for improvement in internal efficiency for efficiently converting thermal energy of steam into mechanical work. As a cause of a decrease in internal efficiency in the steam turbine, there are a leakage effect of effective steam and a braking effect due to excessive moisture.

  As the leakage of the effective steam, for example, there is a phenomenon in which the effective steam in the expansion stage flows out downstream between the turbine casing and the shroud at the top of the rotor blade.

  The rotor blades and shroud that rotate during operation of the steam turbine are installed so as not to interfere with other components, and a gap is provided between the shroud and the turbine casing. When the shroud and the turbine casing interfere with each other, the shroud and the turbine casing are seriously damaged, and much cost and work are required for repair and replacement of parts. Therefore, the gap provided between the shroud and the turbine casing is a sufficiently large space with no risk of interference. Since the steam in the steam turbine is effectively used so that the rotor blades are rotated by being applied to the rotor blades, a gap provided between the shroud and the turbine casing without the steam being applied to the rotor blades. Outflowing downstream through the steam causes a decrease in internal efficiency of the steam turbine.

  There are steam turbines in which one or more labyrinth fins are installed between the shroud and the turbine casing. The labyrinth fin is an annular seal plate, and suppresses steam from flowing out downstream between the shroud and the turbine casing. The labyrinth fin has a small and simple structure as compared with the turbine casing, and is hardly damaged when interfering with the shroud. Therefore, the gap between the shroud and the labyrinth fin can be set narrower than the gap provided between the shroud and the turbine casing, and leakage of effective steam can be reduced. However, the gap between the shroud and the labyrinth fin cannot be eliminated and the leakage of effective steam is still a problem because the steam flows downstream between the shroud and the labyrinth fin.

  The braking effect due to excessive moisture means that the impact force when water droplets scattered from a stationary blade collide with a rotating blade that is installed downstream of the stationary blade works in the opposite direction to the rotation of the moving blade. This is a phenomenon that suppresses rotation. The situation is as follows.

  Steam works with changing conditions such as pressure and temperature drops. For example, the steam supplied from the boiler to the steam turbine is superheated steam, and the degree of superheat decreases as the pressure decreases, resulting in dry saturated steam, and further expanded into wet steam containing moisture. In the wet steam region, moisture easily aggregates on the blade surface of the stationary blade, and the moisture aggregated on the blade surface becomes a water vein, which is blown by the steam flow and flows downstream. When the water vein reaches the trailing edge, which is the wing tip on the downstream side, it scatters and becomes water droplets. The water droplets scattered from the stationary blade collide with the rotating moving blade installed on the downstream side of the stationary blade by the steam flow, causing a braking effect and erosion (erosion phenomenon).

JP-A-3-26802 JP-A-4-350302

  Patent Document 1 and Patent Document 2 are techniques for reducing the braking effect due to leakage of effective steam or excessive moisture, which is the cause of the decrease in internal efficiency.

  A steam turbine according to Patent Document 1 sucks water droplets and water veins flowing on a blade surface from a slit-like suction hole provided in a stationary blade into the blade together with steam, and gas-liquid separation is performed in a blade top ring or a blade root ring of the stationary blade. The vapor-liquid-separated steam is jetted to the blade top portion or the blade root portion of the blade. According to this steam turbine, the erosion and braking effect of the rotor blade is reduced, and the steam is prevented from flowing out from between the rotor disk and the top ring of the stationary blade or between the turbine casing and the shroud of the rotor blade. Can do.

  However, due to the structure of this steam turbine, the structure for ejecting steam near the blade top of the rotor blade is limited to the lower half of the steam turbine, and the structure for ejecting steam near the blade root is in the upper half of the steam turbine. Limited. Therefore, only the lower half of the steam turbine can reduce the effective steam leakage between the shroud and the turbine casing, which is insufficient to improve the internal efficiency.

  The steam turbine according to Patent Document 2 has a structure in which part of steam is sucked into a blade from a slit-like suction hole provided in a stationary blade, and the sucked steam is ejected in the vicinity of a blade top portion of a moving blade. According to this steam turbine, the secondary flow of steam can be prevented and steam can be prevented from flowing out between the shroud and the turbine casing.

  However, this structure of the steam turbine is a technique applied to a steam turbine provided with a high nozzle type stationary blade, which is likely to be deteriorated in internal efficiency due to the secondary flow. Further, depending on the ejection direction when the steam is ejected in the vicinity of the top of the rotor blade, the effective steam may leak together with the ejected steam.

  The present invention has been made in view of the above problems, and an object of the present invention is to reduce effective steam leakage and remove moisture in the steam turbine to improve internal efficiency.

  A steam turbine according to a first aspect of the present invention for solving the above problems includes a plurality of blades whose blade tops are arranged close to the inner peripheral surface of the turbine casing, and an inner portion of the turbine casing so as to be adjacent to the blades. In a steam turbine provided with a plurality of stationary blades held on the circumferential side, a blade inner space that is formed in the stationary blade and is supplied with high-pressure steam having a pressure higher than that of the steam flowing outside the blade. A flow passage that communicates with the blade inner space and that is supplied with the high-pressure steam from the blade inner space, communicates with the flow passage, and faces a gap between the blade top portion of the moving blade and the turbine casing. One or a plurality of seals in which an ejection opening is formed in the turbine casing in the vicinity of the rotor blade, and the high-pressure steam supplied from the inner space of the blade through the flow passage is ejected from the ejection opening Steam And having a introduction ejection unit.

  A steam turbine according to a second aspect of the present invention for solving the above-described problem is characterized in that one or more of the high-pressure steam supplied to the inner space of the stationary blade is jetted out of the stationary blade. It is characterized in that a jet hole is formed.

  In the steam turbine according to a third aspect of the present invention for solving the above-described problem, the ejection hole is formed at 50% or more of the blade width from the front edge portion of the stationary blade and 70% of the blade width from the front edge portion of the stationary blade. It is characterized by being formed in the following range and in a range of 50% or more of the blade height from the outer peripheral side of the stationary blade and 70% or less of the blade height from the outer peripheral side of the stationary blade.

  A steam turbine according to a fourth aspect of the present invention for solving the above-mentioned problems is that the ejection hole is a slit, and the blade width is 50% or more of the blade width from the front edge portion of the stationary blade and from the front edge portion of the stationary blade. It is formed at a position of 70% or less, and is formed with a length of 50% or more of the blade height from the outer peripheral side of the stationary blade and a length of 70% or less of the blade height from the outer peripheral side of the stationary blade. Features.

  A steam turbine according to a fifth invention for solving the above-mentioned problems is characterized in that the high-pressure steam is superheated steam having a pressure higher than that of the steam flowing outside the stationary blade.

  In the steam turbine according to a sixth aspect of the present invention for solving the above-described problem, steam that flows upstream from a position where the stationary blade is installed or steam generated from an external steam supply source is used as the high-pressure steam in the blade. It is supplied to the space.

  A steam turbine according to a seventh aspect of the present invention that solves the above-described problem is provided with one or a plurality of steam turbines on an inner peripheral side of the turbine casing in the vicinity of the moving blade or an outer peripheral side of a shroud attached to the blade top of the moving blade. A labyrinth fin is installed, and the labyrinth in the turbine casing in the vicinity of the rotor blade is disposed so that the seal steam introducing and ejecting portion faces the gap between the blade top portion of the rotor blade and the turbine casing. It is characterized by being formed upstream of the fins.

  A steam turbine according to an eighth aspect of the present invention that solves the above-described problem is the installation of a plurality of labyrinth fins on the inner peripheral side of the turbine casing or on the outer peripheral side of a shroud attached to the top of the moving blade in the vicinity of the moving blade. And a plurality of the labyrinth fins in the turbine casing in the vicinity of the rotor blades so that the seal steam introduction jetting portion faces the gap between the blade top portion of the rotor blade and the turbine casing. It forms in the inner peripheral side of the said turbine casing between any two.

  According to the steam turbine according to the first aspect of the present invention, high pressure steam is passed through the blade inner space of the stationary blade to heat the stationary blade and the moisture on the blade surface evaporates, thereby reducing the erosion and braking effect of the moving blade. Can be made. Moreover, steam flows out from the gap between the rotor blade and the turbine casing to the downstream side by creating a high-pressure space with high pressure locally by ejecting the high-pressure steam from the seal steam introduction and ejection section provided in the turbine casing. Therefore, leakage of effective steam can be reduced regardless of the ejection direction when the steam is ejected to the tip of the rotor blade. By communicating from the space inside the blade of the stationary blade to the seal steam introduction / injection section, it is possible to achieve a reduction in braking effect and a reduction in effective steam leakage in the steam turbine with a single steam path, thereby improving internal efficiency. .

  According to the steam turbine according to the second aspect of the present invention, a part of the high-pressure steam is ejected from the ejection holes formed on the blade surface of the stationary blade, so that it cannot be evaporated by heating the stationary blade. Since the water vein formed by the accumulation of water can be scattered and evaporated as fine water droplets, the water removal effect in the steam turbine can be improved and the internal efficiency can be further improved.

  According to the steam turbine according to the third aspect of the present invention, it is possible to remove moisture with a simple structure by an efficient moisture removing structure, and therefore it is possible to suppress an increase in extra manufacturing cost and a decrease in blade strength. In addition, the high-pressure steam that is ejected from the ejection hole is higher in pressure than the steam that flows outside the blade of the stationary blade, and because of the pressure difference, it is ejected vigorously from the ejection hole. And easy to refine.

  According to the steam turbine concerning the 4th invention, since the ejection hole formed in a stationary blade is simple structure, formation and processing become easy and it can control an increase in manufacturing cost.

  According to the steam turbine of the fifth aspect of the invention, the high-pressure steam is superheated steam having a pressure higher than that of the steam flowing outside the stationary blade, so that the temperature is higher than that of the steam flowing outside the stationary blade. By spraying high-pressure steam from the ejection holes, it is possible to evaporate a part of the fine water droplets.

  According to the steam turbine according to the sixth aspect of the present invention, when the steam flowing upstream from the position where the stationary blade is installed is extracted, there is no increase in equipment other than the steam turbine, thereby suppressing an increase in cost. When steam generated from an external steam supply source is extracted, it is possible to remove moisture from the blades even in nuclear steam turbines where the high-pressure stage is a wet steam region, such as the temperature and pressure of the steam to be extracted Can be adjusted easily.

  According to the steam turbine according to the seventh aspect of the present invention, effective steam flows out from the gap between the moving blade and the turbine casing to the downstream side by installing the labyrinth fin on the inner peripheral side of the turbine casing or the outer peripheral side of the shroud. Leakage can be reduced. In addition, by installing the labyrinth fin in the vicinity of the downstream side of the seal steam introduction / injection part, high-pressure steam ejected from the ejection opening of the seal steam introduction / injection part is surrounded in three directions by the turbine casing, shroud, and labyrinth fin. It becomes easy to keep the high-pressure space created by the generated high-pressure steam in a high-pressure state.

  According to the steam turbine according to the eighth aspect of the present invention, by installing the labyrinth fin on the inner peripheral side of the turbine casing or the outer peripheral side of the shroud, the effective steam from which the steam flows out downstream from the gap between the moving blade and the turbine casing. Leakage can be reduced. In addition, by installing the labyrinth fin in the vicinity of the upstream side and the downstream side of the seal steam introduction / injection part, the high-pressure steam ejected from the ejection opening of the seal steam introduction / injection part is surrounded by the turbine casing, the shroud, and the labyrinth fin. Therefore, it is easy to keep the high-pressure space created by the jetted high-pressure steam in a high-pressure state.

1 is a longitudinal sectional view showing one stage of a steam turbine according to Embodiment 1. FIG. It is an enlarged view which shows the circumference | surroundings of the seal | steam vapor | steam introduction jet part in FIG. 1 is a perspective view illustrating a stationary blade of a steam turbine according to Embodiment 1. FIG. It is a side view which shows the IV direction arrow in FIG. FIG. 4 is a transverse sectional view showing a V section in FIG. 3. 1 is a longitudinal sectional view showing one stage of a steam turbine according to Embodiment 1. FIG. It is explanatory drawing which shows the flow with respect to the downstream rotor blade of the steam and water droplet in a steam turbine. It is explanatory drawing which shows the track analysis result of the particle | grains of 50 micrometers in diameter adhering to a stationary blade. It is explanatory drawing which shows the track analysis result of the particle | grains with a diameter of 100 micrometers adhering to a stationary blade. It is a longitudinal cross-sectional view which shows the example which changed the distribution path of the high pressure superheated steam in the steam turbine which concerns on Example 1. FIG. It is a longitudinal cross-sectional view which shows the example which does not install the labyrinth fin in the steam turbine which concerns on Example 1. FIG. FIG. 6 is a longitudinal sectional view showing one stage of a steam turbine according to a second embodiment. It is a longitudinal cross-sectional view which shows the example which changed the formation location of the seal | sticker steam introduction injection part in the steam turbine which concerns on Example 2. FIG. FIG. 6 is a longitudinal sectional view showing one stage of a steam turbine according to a third embodiment. It is a longitudinal cross-sectional view which shows the example which changed the formation location of the seal steam introduction injection part in the steam turbine which concerns on Example 3. FIG.

  Embodiments 1 to 3 of the steam turbine according to the present invention will be described below in detail with reference to the accompanying drawings. Needless to say, the present invention is not limited to the following examples, and various modifications can be made without departing from the spirit of the present invention.

  A steam turbine according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 11.

  First, the structure of the steam turbine 1 of a present Example is demonstrated.

  As shown in FIG. 1, the steam turbine 1 of this embodiment includes a turbine casing 10, a moving blade 20 provided in the turbine casing 10, a shroud 21 and a rotor disk 22 that hold the moving blade 20, and a stationary blade 30. It has a blade root ring 31 and a blade tip ring 32 for holding.

  The rotor blade 20 is held on the outer peripheral side of a disk-shaped rotor disk 22. A plurality of moving blades 20 are arranged at regular intervals in the circumferential direction of the rotor disk 22 to form a moving blade row. A plurality of rows of moving blades are arranged along the rotor disk 22 at regular intervals in the axial direction.

  Further, the moving blade 20 has a shroud piece on the outer peripheral side (blade top), and a plurality of arc-shaped shroud pieces are connected to form a shroud 21. When the moving blade 20 is deformed by centrifugal force, the shroud piece attached to the moving blade 20 comes into close contact with the shroud piece of the moving blade 20 adjacent in the circumferential direction, and the shroud piece attached to the moving blade 20 on the entire circumference in the circumferential direction. Are in close contact with each other to form an annular shroud 21.

  The stationary blade 30 is installed between an annular blade root ring 31 and a blade top ring 32, and is held on the inner peripheral side of the turbine casing 10 by the blade root ring 31. A plurality of the stationary blades 30 are arranged at regular intervals in the circumferential direction of the blade root ring 31 and the blade top ring 32 to form a stationary blade row. The stationary blade rows are arranged in a plurality of rows at regular intervals alternately with the moving blade rows in the axial direction together with the blade root ring 31 and the blade top ring 32.

  Each row of adjacent stationary blade rows and moving blade rows is made into one stage, and the steam pressure is different for each stage. In other words, a high-speed steam flow is obtained by setting the downstream stage of the adjacent stages to a space having a lower pressure than the upstream stage. The steam turbine 1 of the present embodiment has a structure having a steam sealing function for reducing leakage of effective steam and a moisture removing function for reducing a braking effect due to excessive moisture in a low-pressure stage that becomes a wet steam region. .

  Next, a structure (steam sealing mechanism) that achieves a steam sealing function for reducing leakage of effective steam will be described with reference to FIGS. 1 and 2.

  As shown in FIG. 2, the shroud 21 and the turbine casing 10 are installed with a gap 40 so that the shroud 21 and the turbine casing 10 do not come into contact with each other when the moving blade 20 rotates. Since the moving blade 20 is deformed by receiving centrifugal force due to the rotational operation, the gap 40 provided between the shroud 21 and the turbine casing 10 is a sufficiently large space.

  One labyrinth fin 50 is installed on the inner peripheral side of the turbine casing 10 in the vicinity of the shroud 21. The labyrinth fin 50 is an annular seal plate that extends over the entire inner circumference of the turbine casing 10 and prevents the steam 60 flowing through the stage from flowing out downstream through the gap 40 described above. The labyrinth fin 50 has a small and simple structure as compared with the turbine casing 10, and damage caused when the labyrinth fin 50 interferes with the shroud 21 is slight. Therefore, the labyrinth fin 50 is smaller than the gap 40 provided between the shroud 21 and the turbine casing 10. And the labyrinth fin 50 can be set narrow.

  Of course, the number of labyrinth fins 50 is not limited to the present embodiment, and a plurality of labyrinth fins 50 may be installed. Further, the shape of the labyrinth fin 50 is not limited to the present embodiment. For example, it is good also as a structure divided | segmented into the circumferential direction which comprises the cyclic | annular form over the perimeter of the inner peripheral side of the turbine casing 10 by integrating | stacking a some sealing plate piece integrally, and it is sufficient to have a several seal | sticker performance to such an extent that seal performance is not impaired remarkably. You may install a sealing board piece intermittently, providing a clearance gap in the circumferential direction. Further, the labyrinth fin 50 may be installed on the shroud 21.

  A seal steam introduction jet portion forming an annular groove communicating with the entire circumference of the turbine casing 10 on the upstream side of the position where the labyrinth fin 50 is installed in the turbine casing 10 in the vicinity of the shroud 21 (or the blade top portion of the moving blade 20). 70 is formed. The seal steam introduction jet part 70 is for jetting the high-pressure superheated steam 61, and is formed so that the jet opening 71 faces the gap 40 between the shroud 21 and the turbine casing 10. The high pressure superheated steam 61 is ejected into the gap 40 between the shroud 21 and the turbine casing 10 to create a high pressure space 80 having a locally high pressure. Since the steam flows from the high pressure space to the low pressure space, the steam 60 flowing through the stage does not flow into the gap 40 between the shroud 21 having the high pressure space 80 and the turbine casing 10, and the moving blade on the inner peripheral side of the shroud 21. It flows to 20.

  By making the shape of the seal steam introduction jet part 70 into an annular groove that communicates over the entire circumference of the turbine casing 10, a high-pressure space 80 can be created over the entire circumference of the gap 40 between the shroud 21 and the turbine casing 10. . Moreover, since the high pressure space 80 is surrounded by the turbine casing 10, the shroud 21, and the labyrinth fin 50 by making the high pressure space 80 upstream from the position where the labyrinth fin 50 is installed, the high pressure space 80 is in a high pressure state. Easy to keep.

  Of course, the shape and forming position of the seal steam introduction / injection portion 70 are not limited to the present embodiment, and the seal steam introduction / injection portion 70 is formed with a plurality of slits or a plurality of circular holes in consideration of the structure and strength of the turbine casing 10. May be formed intermittently in the circumferential direction of the turbine casing 10, and may be formed downstream of the position where the labyrinth fin 50 is installed as long as it is in the vicinity of the shroud 21.

  The high-pressure superheated steam 61 ejected from the ejection opening 71 of the seal steam introducing / injecting section 70 is steam having a pressure higher than that of the steam 60 flowing through the stage, and is supplied from the stage upstream of the stage in the steam turbine 1 of the present embodiment. As shown in FIG. 1, one or a plurality of first flow passages 11 are formed in the turbine casing 10 in the circumferential direction so as to communicate with the seal steam introduction / injection portion 70, and the first flow passage 11 is connected from the upstream stage through the first flow passage 11. The high-pressure superheated steam 61 thus supplied is jetted from the seal steam introduction jetting portion 70 toward the gap 40 between the shroud 21 and the turbine casing 10. The high pressure superheated steam 61 supplied from the upstream stage through the first flow passage 11 is formed by forming the seal steam introduction jetting portion 70 with a smaller cross-sectional area than the first flow passage 11. The high pressure superheated steam 61 can be brought into a higher pressure state when flowing to the introduction jetting part 70.

  Of course, the supply source of the high-pressure superheated steam 61 ejected from the ejection opening 71 of the seal steam introduction ejection section 70 is not limited to this embodiment, and a steam supply source such as an external boiler is provided by installing piping outside the turbine casing 10. Alternatively, the high pressure superheated steam 61 may be supplied.

  Next, a structure (moisture removal mechanism) that achieves a moisture removal function for reducing the braking effect due to excessive moisture will be described with reference to FIGS. 1 and 3 to 10.

  The moisture removal function of the present embodiment uses high-pressure superheated steam 61 supplied from an upstream stage in order to eject from the ejection opening 71 of the seal steam introduction jetting part 70, and the high-pressure superheated steam 61 causes the stationary blade 30 to move. The function of evaporating water droplets and water veins 91 adhering to the blade surface by heating (hereinafter, referred to as an evaporation function such as a water droplet) and a part of the high-pressure superheated steam 61 from the blade surface of the stationary blade 30 It has a function of refining the water vein 91 (hereinafter referred to as a water refining function).

  First, a structure that achieves an evaporation function such as a water droplet will be described with reference to FIGS. 1, 5, and 10.

  As shown in FIG. 1, a blade inner space 33 is formed in the stationary blade 30, the downstream side communicates with the first flow passage 11 described above via a blade root ring 31, and the upstream side via a blade root ring 31. Then, the second flow path 12 formed in the turbine casing 10 is communicated. The first flow passage 11 is a flow path for supplying the high-pressure superheated steam 61 from the blade inner space 33 to the seal steam introduction jetting portion 70, and the second flow passage 12 is the high-pressure superheated steam 61 from the upstream stage to the blade inner space 33. Is a distribution channel for supplying Since the high-pressure superheated steam 61 supplied from the upstream stage is at a higher temperature than the steam 60 flowing outside the blades of the stationary blade 30 installed in the stage, the high-pressure superheated steam 61 passes through the blade inner space 33 so that the stationary blade 30 is heated, and water droplets accumulated on the blade surface of the stationary blade 30 and water veins 91 formed by the accumulation of water droplets are evaporated.

  In addition, as shown in FIG. 5, the water droplet adhesion range of the stationary blade 30 described later is formed by forming the blade inner space 33 along the back side 100 in the vicinity of the front edge portion 102 that is the upstream side of the stationary blade 30. 92 (see FIG. 8 and FIG. 9) has a structure that is easy to heat.

  Of course, the shape of the blade inner space 33 is not limited to the present embodiment, and may be a space extending throughout the stationary blade 30. Further, the flow path of the high-pressure superheated steam 61 is not limited to the turbine casing 10 as in this embodiment. Piping may be installed outside the turbine casing 10, and as shown in FIG. 10, an in-ring passage 34 may be formed inside the top ring 32 of the stationary blade 30.

  Next, a structure that achieves the function of miniaturizing water droplets and the like will be described with reference to FIGS.

  As shown in FIG. 3, slit-like ejection holes 110 for ejecting high-pressure superheated steam 61 are formed on the back side 100, which is the convex curved surface side of the stationary blade 30. As shown in FIG. 4, the ejection hole 110 of the stationary blade 30 in the low pressure stage of the steam turbine 1 of the present embodiment is a linear slit along the blade height H direction, and the ejection hole forming position X is set to the blade. 70% of the width W and the jet hole formation length Y are set to 70% of the blade height H.

  Here, the ejection hole formation position X is a distance (distance in the axial direction of the rotor disk 22) from the front edge portion 102 on the upstream side of the stationary blade 30, and the ejection hole formation length Y is the distance of the stationary blade 30. The distance from the blade bottom 104 on the outer peripheral side (the distance in the radial direction of the rotor disk 22). The blade width W is the width of the blade (the chord length of the blade in the axial direction of the rotor disk 22). In the case of a blade whose cross-sectional area changes from the blade bottom 104 to the blade top 105, the blade width W is the maximum width. The blade height H is the blade height (blade length in the radial direction of the rotor disk 22) at the nozzle hole forming position X in which the slit-shaped nozzle hole 110 is formed. The blade height H depends on the nozzle hole forming position X. H is different.

  The high pressure superheated steam 61 supplied to the blade inner space 33 has a higher pressure than the steam 60 flowing outside the blades of the stationary blades 30 installed in the stage, and a part of the high pressure superheated steam 61 is statically discharged from the ejection holes 110. Since the wings 30 are ejected vigorously out of the wings, the effect of the function of miniaturizing the water droplets and the water veins 91 can be improved. Further, the high-pressure superheated steam 61 is a superheated steam having a temperature higher than the saturation temperature at the pressure, and a part of the water droplets refined by ejecting the high-pressure superheated steam 61 from the ejection holes 110 is evaporated. In parallel with the function of evaporating water droplets and water veins 91 adhering to the water, the effect of removing water can be improved.

  Next, an analysis for determining the ejection hole formation position X and the ejection hole formation length Y of the ejection hole 110 formed in the stationary blade 30 in the present embodiment will be described with reference to FIGS. 4 and 6 to 9. To do.

  The erosion and braking effect that occurs in the moving blade 20 is that the water vein 91 that flows on the blade surface of the stationary blade 30 that is adjacent to the moving blade 20 and located upstream is scattered from the trailing edge 103 of the stationary blade 30 by the steam flow. This is caused by water droplets. As shown in FIG. 6, the water vein 91 on the blade surface of the stationary blade 30 is scattered from the blade 20 by the steam flow on the surface of the moving blade 20 adjacent to the stationary blade 30 and located upstream. Water droplets generated by doing so can adhere to the stationary blade 30 and aggregate.

  The water droplets scattered from the moving blade 20 in the wet steam region of the steam turbine 1 can be divided into three according to the size. The fine water droplet 90a having a diameter of about several μm smaller than the diameter of 50 μm has a small mass and flows downstream along the steam flow, and therefore does not adhere to the stationary blade 30 adjacent to the moving blade 20 and located downstream. Medium-sized water droplets 90 b having a diameter of about 50 to 100 μm are attached to the stationary blade 30 located adjacent to the moving blade 20 on the downstream side, and aggregate on the blade surface of the stationary blade 30 to form a water vein 91. Coarse water droplets 90c having a diameter of several hundred μm larger than the diameter of 100 μm have a large mass and are greatly affected by the centrifugal force due to the rotation of the rotor blade 20, and therefore flow toward the turbine casing 10 on the outer peripheral side of the stationary blade 30; It does not adhere to the stationary blade 30 located adjacent to the moving blade 20 and on the downstream side.

  As shown in FIG. 7, regarding the flow of steam and water droplets in the steam turbine 1 with respect to the moving blade 20, the steam flows at a high speed toward the outlet of the moving blade 20 (steam vector α <b> 1), and the water droplets move in the same direction as the steam. It flows at a slow speed (water droplet vector β1). Since the mass of the water droplet is larger than that of the steam, the speed of the water droplet is slower than that of the steam.

  Next, with respect to the flow of the steam and water droplets with respect to the stationary blade 30 located on the downstream side of the moving blade 20, the inertia due to the rotation of the moving blade 20 is considered (the moving blade vector γ). Since the water droplet has a mass larger than that of the vapor, the velocity is slow, and the inertia due to the rotation of the moving blade 20 greatly affects the direction in which the water droplet flows. Therefore, the steam flows toward the ventral side 101 of the stationary blade 30 positioned on the downstream side (steam vector α2), and the water droplet flows toward the back side 100 of the stationary blade 30 positioned on the downstream side (water droplet vector β2).

  That is, of the water droplets scattered from the moving blade 20, an intermediate large water droplet 90 b having a diameter of about 50 to 100 μm is attached to the back side 100 of the stationary blade 30 that is adjacent to the moving blade 20 and located downstream.

  As shown in FIG. 8, a water droplet adhesion range 92 when a water droplet having a diameter of 50 μm adheres to the back side 100 of the stationary blade 30 is within 70% of the blade width W from the front edge portion 102 of the stationary blade 30, and It is within 70% of the blade height H from the blade bottom 104 on the outer peripheral side.

  As shown in FIG. 9, a water droplet adhesion range 92 when a water droplet having a diameter of 100 μm adheres to the back side 100 of the stationary blade 30 is within 50% of the blade width W from the front edge portion 102 of the stationary blade 30, and It is within 50% of the blade height H from the blade bottom 104 on the outer peripheral side.

  That is, the medium-sized water droplet 90b having a diameter of about 50 to 100 μm is 50 to 70% of the blade width W from the front edge portion 102 on the back side 100 of the stationary blade 30 and from the blade bottom portion 104 on the outer peripheral side to the blade. It adheres within the range of 50 to 70% of the height H, that is, within the water droplet adhesion range 92. Therefore, as shown in FIG. 4, the ejection hole formation position X is set in the range of 50 to 70% of the blade width W, and the ejection hole formation length Y is set in the range of 50 to 70% of the blade height H. By using the slit-shaped ejection hole 110, it is possible to efficiently remove moisture.

  In the steam turbine 1 according to the present embodiment, since the water droplets 90b having a diameter of about 50 to 100 μm are generated evenly at the stage where the stationary blade 30 having the moisture removing function is installed, the ejection hole forming position X is set to the blade. A slit-like ejection hole 110 having a width W of 70% and an ejection hole formation length Y of 70% of the blade height H was formed. For example, when there are not many water droplets having a diameter of about 50 μm and many water droplets having a diameter of about 100 μm are generated, the ejection hole formation position X is set to 50% of the blade width W and the ejection hole formation length Y is set to the A slit-like ejection hole 110 may be formed as 50% of the blade height H.

  The size of the water droplets and the water droplet adhesion range 92 that are likely to be generated vary depending on various conditions. Therefore, in accordance with these water droplet scattering conditions, the ejection hole formation position X, which is the distance from the leading edge portion 102 of the blade forming the slit-shaped ejection hole 110, is in the range of 50% to 70% of the blade width W. The ejection hole formation length Y, which is the distance from the blade bottom 104 on the outer peripheral side of the stationary blade 30 forming the slit-shaped ejection hole 110, is 50% or more and 70% or less of the blade height H. It is preferable to select from the range.

  Of course, even when the ejection hole 110 is formed outside the above range, the water droplets adhering to the blade surface of the stationary blade 30 and the water vein 91 formed by collecting the water droplets are scattered to remove the water in the steam turbine 1. Needless to say, you can. Therefore, the ejection hole 110 may be formed on the ventral side 101 or the entire surface of the stationary blade 30.

  Further, if moisture can be sufficiently removed only by the structure that achieves the function of evaporating water droplets or the like by heating the stationary blade 30 with the high-pressure superheated steam 61 described above, the stationary blade 30 communicates with the blade inner space 33. The ejection hole 110 may not be formed.

  Next, operation | movement of the steam turbine 1 of a present Example is demonstrated.

  The steam sent to the steam turbine 1 of the present embodiment is superheated steam, and the degree of superheat is reduced to dry saturated steam as it expands with pressure drop, and further expands to wet steam containing moisture.

  As shown in FIGS. 6, 8, and 9, in the low-pressure stage that is a wet steam region in the steam turbine 1 of the present embodiment, fine water droplets 90 a among the water droplets in the wet steam or the water droplets scattered from the moving blade 20. Is light and flows downstream along with the steam 60, and the coarse water droplet 90c is heavy and thus receives a large centrifugal force and scatters toward the turbine casing 10, while the intermediate water droplet 90b moves and moves with the flow of the steam 60. Due to the inertia of the rotation of the blade 20, the centrifugal force acting in the range of 70% of the blade width from the front edge portion 102 on the back side 100 of the stationary blade 30 adjacent to the moving blade 20 and located downstream is applied to the outer peripheral side. The blade adheres in the range of 70% of the blade height H from the blade bottom 104 on the outer peripheral side of the stationary blade 30, that is, in the water droplet adhesion range 92.

  Since the stationary blade 30 is heated from the inside by the high-pressure superheated steam 61 supplied to the blade inner space 33, water droplets adhering to the surface of the stationary blade 30 and a part of the water vein 91 formed by aggregation of water droplets evaporate. Then, it becomes steam 60 and flows downstream. In addition, since the blade inner space 33 is formed along the back side 100 on the upstream side of the ejection hole 110 that is the water droplet adhesion range 92, the high pressure superheated steam 61 leads to the water droplets and the water vein 91 on the surface of the stationary blade 30. Heat can be transferred efficiently.

  As shown in FIG. 4, extra water droplets and water veins 91 that could not be evaporated again aggregate again to form new water veins 91 that flow downstream on the blade surface of the stationary blade 30 (water vein flow direction 91d). Then, the water vein 91 is formed on the back side 100 of the stationary blade 30 from the front edge portion 102 to an ejection hole forming position X that is 70% of the blade width W, and from the blade bottom portion 104 on the outer peripheral side of the stationary blade 30 to the blade height. It reaches the slit-shaped ejection hole 110 formed with the ejection hole formation length Y of 70% of the length H.

  As shown in FIG. 5, the high-pressure superheated steam 61 supplied to the blade inner space 33 is ejected vigorously from the slit-shaped ejection hole 110. Therefore, the water vein 91 reaching the ejection hole 110 is scattered from the surface of the stationary blade 30 into the steam 60 and flows downstream as fine water droplets 90a having a diameter smaller than 50 μm. Further, some of the scattered fine water droplets 90 a are evaporated by the heat of the high-pressure superheated steam 61 ejected from the ejection holes 110 of the stationary blade 30.

  Therefore, according to the steam turbine 1 according to the present embodiment, the water droplets scattered from the stationary blades 30 in the wet steam region become the fine water droplets 90a having a diameter smaller than 50 μm, and the moving blades 20 located on the downstream side of the stationary blades 30 The medium-sized water droplet 90b that can collide can be removed. This leads to a reduction in the erosion phenomenon occurring in the rotor blade 20 and the braking effect.

  In addition, since the size of water droplets that are likely to be generated and the range that is liable to adhere to the stationary blades 30 differ depending on the type or stage of the steam turbine 1, the ejection hole forming position X for forming the ejection holes 110 in the stationary blades 30 and The ejection hole formation length Y is not limited to the present embodiment. For each stationary blade 30 with different water droplet scattering conditions, the ejection hole formation position X is set in the range of 50% to 70% of the blade width W from the leading edge 102 of the stationary blade 30 to form ejection holes. The length Y may be set in a range from 50% to 70% of the blade height H from the blade bottom 104 on the outer peripheral side of the stationary blade 30.

  Moreover, the shape of the ejection hole 110 is not limited to the linear slit along the radial direction as shown in FIG. 4, and the ejection hole has a shape that takes into account the ease of formation of the ejection hole 110 and the strength of the blades. 110. For example, within the range of 50% to 70% of the blade width W from the leading edge 102 of the stationary blade 30, and within the range of 50% to 70% of the blade height H from the outer peripheral side of the stationary blade 30. If it exists, it may be a slit inclined with respect to the radial direction or a wavy slit, or may be a broken-line slit or a plurality of holes.

  Next, as shown in FIG. 1, the high pressure superheated steam 61 passes through the first flow passage 11 in the turbine casing 10 from the seal steam introduction jetting portion 70 formed in the turbine casing 10 and the gap between the shroud 21 and the turbine casing 10. It spouts toward 40. At this time, since the jet opening 71 of the seal steam introduction jet part 70 is formed smaller than the cross section of the first flow passage 11, the high pressure superheated steam 61 is jetted into the gap 40 in a higher pressure state.

  As shown in FIG. 2, the high-pressure superheated steam 61 ejected from the ejection opening 71 of the seal steam introduction ejection section 70 creates a local high-pressure space 80 in the gap 40 between the shroud 21 and the turbine casing 10. The high-pressure space 80 acts as a pressure wall and prevents the steam 60 flowing through the stage from flowing out from the gap 40 to the downstream side.

  By installing the labyrinth fin 50 on the inner peripheral side of the turbine casing 10, it is possible to prevent the steam 60 flowing through the stage from flowing out from the gap 40 between the moving blade 20 and the turbine casing 10 to the downstream side.

  By jetting the high-pressure superheated steam 61 in the vicinity of the upstream side of the labyrinth fin 50, the high-pressure superheated steam 61 ejected from the ejection opening 71 of the seal steam introduction jet section 70 is moved in three directions by the turbine casing 10, the shroud 21 and the labyrinth fin 50. Will be surrounded. Therefore, the high pressure space 80 created by the jetted high pressure superheated steam 61 is easily kept in a high pressure state. In addition, since the high-pressure space 80 is created upstream of the position where the labyrinth fin 50 is installed, the high-pressure superheated steam 61 flows downstream by installing the labyrinth fin 50 in the vicinity of the downstream side of the seal steam introduction jetting portion 70. Can be reduced.

  As described above, it is possible to obtain a sufficient effect in reducing effective steam leakage and braking effect due to excessive moisture. The steam turbine 1 according to the present embodiment has an efficient structure in which the high-pressure superheated steam 61 can be used in two applications of reducing effective steam leakage and reducing braking effect due to excessive moisture in one steam path. Internal efficiency can be improved.

  Of course, even when the ejection hole 110 is not formed in the stationary blade 30, the stationary blade 30 is heated by the high-pressure superheated steam 61 passing through the blade inner space 33, and water droplets and water droplets accumulated on the blade surface of the stationary blade 30 are collected. Needless to say, the accumulated water veins 91 are evaporated, so that a sufficient effect can be obtained in reducing the braking effect due to excessive moisture.

  Further, as shown in FIG. 11, it goes without saying that even when the labyrinth fin 50 is not installed on the inner peripheral side of the turbine casing 10 in the vicinity of the shroud 21, a sufficient effect can be obtained in reducing leakage of effective steam. The high-pressure superheated steam 61 ejected from the ejection opening 71 of the seal steam introduction ejection portion 70 formed so as to face the gap 40 creates a local high-pressure space 80 in the gap 40 between the shroud 21 and the turbine casing 10, and Can be prevented from flowing out from the gap 40 to the downstream side.

  A second embodiment of the present invention will be described with reference to FIGS.

  The steam turbine 1 of the present embodiment has the same structure as that of the first embodiment except for the number of labyrinth fins 50 and the formation position of the seal steam introduction / injection portion 70, and therefore, duplicate description of the same structure is omitted.

  As shown in FIG. 12, two labyrinth fins 50 are installed on the inner peripheral side of the turbine casing 10 in the vicinity of the shroud 21. The labyrinth fin 50 is an annular seal plate that extends over the entire inner circumference of the turbine casing 10 and prevents the steam 60 flowing through the stage from flowing out downstream through the gap 40 described above. The labyrinth fin 50 has a small and simple structure as compared with the turbine casing 10, and damage caused when the labyrinth fin 50 interferes with the shroud 21 is slight. Therefore, the labyrinth fin 50 is smaller than the gap 40 provided between the shroud 21 and the turbine casing 10. And the labyrinth fin 50 can be set narrowly.

  Of course, the shape of the labyrinth fin 50 is not limited to the present embodiment. For example, it is good also as a structure divided | segmented into the circumferential direction which comprises the cyclic | annular form over the perimeter of the inner peripheral side of the turbine casing 10 by integrating | stacking a some sealing plate piece integrally, and it is sufficient to have a several seal | sticker performance to such an extent that seal performance is not impaired remarkably. You may install a sealing board piece intermittently, providing a clearance gap in the circumferential direction. Further, the labyrinth fin 50 may be installed on the outer peripheral side of the shroud 21.

  While the two labyrinth fins 50 in the turbine casing 10 in the vicinity of the shroud 21 are installed, a seal steam introduction jetting portion 70 that forms an annular groove that communicates with the entire circumference of the turbine casing 10 is formed. The seal steam introduction jet part 70 is for jetting the high-pressure superheated steam 61, and is formed so that the jet opening 71 faces the gap 40 between the shroud 21 and the turbine casing 10. The high-pressure superheated steam 61 ejected from the ejection opening 71 of the seal steam introducing / injecting section 70 is in a state where the four directions are surrounded by the turbine casing 10, the shroud 21 and the two labyrinth fins 50. Therefore, it becomes easy to keep the high pressure space 80 created by the jetted high pressure superheated steam 61 in a high pressure state.

  Of course, the shape and forming position of the seal steam introduction / injection portion 70 are not limited to the present embodiment, and the seal steam introduction / injection portion 70 is formed with a plurality of slits or a plurality of circular holes in consideration of the structure and strength of the turbine casing 10. May be formed intermittently in the circumferential direction of the turbine casing 10, and if it is in the vicinity of the shroud 21, the seal steam introduction / injection portion 70 is formed upstream or downstream of the position where the two labyrinth fins 50 are installed. May be.

  Further, the number of the seal steam introduction / injection portions 70 is not limited to the present embodiment, and a plurality of seal steam introduction / injection portions 70 may be formed. For example, as shown in FIG. 13, in the turbine casing 10 in the vicinity of the shroud 21, the seal steam introducing and ejecting portions 70 are respectively provided between the two labyrinth fins 50 and upstream of the positions where the two labyrinth fins 50 are installed. It may be formed. Since the range of the high-pressure space 80 is widened by the two seal steam introduction jetting portions 70, the sealing performance for preventing the steam 60 flowing through the stage from flowing out from the gap 40 to the downstream side is improved.

  Note that the position where the seal steam introducing / injecting portion 70 is formed is such that the high pressure space 80 formed by the high pressure superheated steam 61 is surrounded by the turbine casing 10, the shroud 21, and the two labyrinth fins 50 in four directions. It is most preferable that two labyrinth fins 50 are installed. Next, the high-pressure space 80 created by the high-pressure superheated steam 61 is in a state where three directions are surrounded by the turbine casing 10, the shroud 21 and the labyrinth fin 50, and the labyrinth fin 50 is placed in the vicinity of the downstream side of the seal steam introduction jet part 70. Since the installation can reduce the outflow of the high-pressure superheated steam 61 to the downstream side, the upstream side is preferable to the position where the two labyrinth fins 50 are installed. Finally, since the high-pressure space 80 created by the high-pressure superheated steam 61 is surrounded by the turbine casing 10, the shroud 21, and the labyrinth fin 50, the downstream side of the position where the two labyrinth fins 50 are installed. The range of is preferable.

  A third embodiment of the present invention will be described with reference to FIGS. 14 and 15.

  The steam turbine 1 according to the present embodiment has the same structure as that of the first embodiment except for the number of rows of the labyrinth fins 50 and the position where the seal steam introduction / injection part 70 is formed. To do.

  As shown in FIG. 14, three labyrinth fins 50 are installed in the axial direction on the inner peripheral side of the turbine casing 10 in the vicinity of the shroud 21. The labyrinth fin 50 is an annular seal plate that extends over the entire inner circumference of the turbine casing 10 and prevents the steam 60 flowing through the stage from flowing out downstream through the gap 40 described above. The labyrinth fin 50 has a small and simple structure as compared with the turbine casing 10, and damage caused when the labyrinth fin 50 interferes with the shroud 21 is slight. Therefore, the labyrinth fin 50 is smaller than the gap 40 provided between the shroud 21 and the turbine casing 10. And the labyrinth fin 50 can be set narrowly.

  Of course, the shape of the labyrinth fin 50 is not limited to the present embodiment. For example, it is good also as a structure divided | segmented into the circumferential direction which comprises the cyclic | annular form over the perimeter of the inner peripheral side of the turbine casing 10 by integrating | stacking a some sealing plate piece integrally, and it is sufficient to have a several seal | sticker performance to such an extent that seal performance is not impaired significantly. You may install a sealing board piece intermittently, providing a clearance gap in the circumferential direction. Further, the labyrinth fin 50 may be installed on the outer peripheral side of the shroud 21. Further, the number of rows of the labyrinth fins 50 is not limited to three, and may be four or more.

  Among the three labyrinth fins 50 in the turbine casing 10 in the vicinity of the shroud 21, a seal steam introduction jet part 70 that forms an annular groove that communicates with the entire circumference of the turbine casing 10 between two labyrinth fins 50 installed upstream. Form. The seal steam introduction jet part 70 is for jetting the high-pressure superheated steam 61, and is formed so that the jet opening 71 faces the gap 40 between the shroud 21 and the turbine casing 10. The high-pressure superheated steam 61 ejected from the ejection opening 71 of the seal steam introducing / injecting section 70 is in a state where the four directions are surrounded by the turbine casing 10, the shroud 21 and the two labyrinth fins 50. Therefore, it becomes easy to keep the high pressure space 80 created by the jetted high pressure superheated steam 61 in a high pressure state.

  Of course, the shape and forming position of the seal steam introduction / injection portion 70 are not limited to the present embodiment, and the seal steam introduction / injection portion 70 is formed with a plurality of slits or a plurality of circular holes in consideration of the structure and strength of the turbine casing 10. May be formed intermittently in the circumferential direction of the turbine casing 10, and if near the shroud 21, the seal steam introduction jet part 70 is formed upstream or downstream from the position where the three labyrinth fins 50 are installed. May be.

  Further, the number of the seal steam introduction / injection portions 70 is not limited to the present embodiment, and a plurality of seal steam introduction / injection portions 70 may be formed. For example, as shown in FIG. 15, in the turbine casing 10 near the shroud 21, the two labyrinth fins 50 are installed while the two upstream labyrinth fins 50 are installed, and the three labyrinth fins 50 are installed. You may form the seal | sticker vapor | steam introduction jet part 70 in an upstream rather than a position, respectively. Since the range of the high-pressure space 80 is expanded by the three seal steam introduction jetting portions 70, the sealing performance for preventing the steam 60 flowing through the stage from flowing out from the gap 40 to the downstream side is improved.

  Note that the position where the seal steam introducing / injecting portion 70 is formed is such that the high pressure space 80 formed by the high pressure superheated steam 61 is surrounded by the turbine casing 10, the shroud 21, and the two labyrinth fins 50 in four directions. It is most preferable that two upstream labyrinth fins 50 are installed or two downstream labyrinth fins are installed. Next, the high-pressure space 80 created by the high-pressure superheated steam 61 is in a state where three directions are surrounded by the turbine casing 10, the shroud 21 and the labyrinth fin 50, and the labyrinth fin 50 is placed in the vicinity of the downstream side of the seal steam introduction jet part 70. Since it can reduce that the high pressure superheated steam 61 flows out downstream by installing, the range of an upstream side is preferable rather than the position where the three labyrinth fins 50 were installed. Finally, the high-pressure space 80 created by the high-pressure superheated steam 61 is in a state where the three directions are surrounded by the turbine casing 10, the shroud 21, and the labyrinth fin 50, and is located downstream of the position where the three labyrinth fins 50 are installed. A range is preferred.

DESCRIPTION OF SYMBOLS 1 Steam turbine 10 Turbine casing 11 1st flow path 12 2nd flow path 20 Rotor blade 21 Shroud 22 Rotor disk 30 Stator blade 31 Blade root ring 32 Blade top ring 33 Blade inner space 34 Ring flow channel 40 Turbine casing Clearance 41 between the shroud Clearance 50 between the labyrinth fin and the shroud 50 Labyrinth fin 60 Steam 61 High pressure superheated steam 70 Seal steam introduction jet part 71 Jet opening 80 High pressure space 90a Fine water droplet 90b Medium water droplet 90c Coarse water droplet 91 Water vein 91 d Water vein flow direction 92 Water drop adhesion range 100 Stator blade dorsal side 101 Stator blade ventral side 102 Stator blade leading edge 103 Stator blade trailing edge 104 Stator blade bottom 105 Stator blade top 110 Hole X Spout-hole formation position Y Spout-hole formation length W Stator blade width H Stator blade height

Claims (8)

Steam comprising a plurality of moving blades whose blade tops are arranged close to the inner peripheral surface of the turbine casing, and a plurality of stationary blades held on the inner peripheral side of the turbine casing so as to be adjacent to the moving blades In the turbine,
A blade inner space that is formed in the stationary blade and is supplied with high-pressure steam having a pressure higher than that of the steam flowing outside the stationary blade;
A flow passage that is in communication with the space in the blade and is supplied with the high-pressure steam from the space in the blade;
An ejection opening is formed in the turbine casing in the vicinity of the rotor blade so as to face a gap between the blade top portion of the rotor blade and the turbine casing, and communicated with the flow passage, and from the blade inner space, the A steam turbine, comprising: one or a plurality of seal steam introducing and ejecting portions through which the high-pressure steam supplied through the flow passage is ejected from the ejection opening.   The one or a plurality of ejection holes in which a part of the high-pressure steam supplied to the inner space of the stationary blade is ejected to the outside of the stationary blade is formed in the stationary blade. Steam turbine.   The ejection hole is formed in a range of 50% or more of the blade width from the leading edge of the stationary blade and 70% or less of the blade width from the leading edge of the stationary blade, and the blade height from the outer peripheral side of the stationary blade. The steam turbine according to claim 2, wherein the steam turbine is formed in a range of 50% or more of the height and 70% or less of the blade height from the outer peripheral side of the stationary blade.   The ejection hole is formed as a slit, formed at a position of 50% or more of the blade width from the leading edge of the stationary blade and 70% or less of the blade width from the leading edge of the stationary blade, and the outer periphery of the stationary blade 4. The steam turbine according to claim 2, wherein the steam turbine has a length of 50% or more of the blade height from the side and a length of 70% or less of the blade height from the outer peripheral side of the stationary blade. 5. .   The steam turbine according to any one of claims 1 to 4, wherein the high-pressure steam is superheated steam having a higher pressure than steam flowing outside the stationary blade. As the high-pressure steam,
The steam flowing upstream from the position where the stationary blade is installed or the steam generated from an external steam supply source is supplied to the space in the blade. The steam turbine according to one item. One or more labyrinth fins are installed on the inner peripheral side of the turbine casing in the vicinity of the moving blade or on the outer peripheral side of the shroud attached to the blade top of the moving blade,
The seal steam introducing and ejecting portion is disposed upstream of the labyrinth fin in the turbine casing in the vicinity of the rotor blade such that the ejection opening faces a gap between the blade top portion of the rotor blade and the turbine casing. It forms, The steam turbine as described in any one of Claim 1 thru | or 6 characterized by the above-mentioned. A plurality of labyrinth fins are installed on the inner peripheral side of the turbine casing in the vicinity of the moving blade or on the outer peripheral side of the shroud attached to the blade top of the moving blade,
A plurality of the labyrinth fins in the turbine casing in the vicinity of the rotor blade so that the seal steam introducing and ejecting portion faces the gap between the blade top of the rotor blade and the turbine casing. It forms in the inner peripheral side of the said turbine casing between two, The steam turbine as described in any one of Claim 1 thru | or 6 characterized by the above-mentioned.

Images