JP4101358B2 - Turbine vane - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
More specifically, the present invention relates to a stationary blade of a turbine, and more specifically, the rotor blade is driven by a steam jet having velocity energy that has a steam passage and jets high-pressure steam from the steam passage to the rotor blade. The present invention relates to a stationary vane of a steam turbine that relatively rotationally drives the turbine.
[0002]
[Prior art]
Steam turbines that expand the steam and convert the thermal energy of the steam into mechanical work are widely used for generators or for driving compressors in chemical plants because they can achieve high horsepower and high-speed rotation.
It can be classified into several types according to the steam power operation method and the steam flow direction, etc., but in any type of turbine, it is generated in a boiler (not shown) as shown in FIG. A stationary blade 2 that forms a steam passage 10 through which the high-pressure and high-temperature steam 1 is ejected, and a blade-shaped cross-sectional profile that generates a rotational force as indicated by an arrow F by receiving a steam jet that has obtained velocity energy. The unit is a set of paragraphs composed of the rotor blades 3.
[0003]
As shown in FIG. 7, in the conventional turbine, the stationary blade 2 has a large number of nozzle plates 21 having a blade-shaped cross-sectional profile arranged on the partition plate 5 in the circumferential direction. Further, the partition plate 15 is fixed to the turbine casing 12. On the other hand, the blade 3 has a blade root 6 implanted radially on the outer periphery of the rotor 4 (see FIG. 6).
[0004]
[Problems to be solved by the invention]
By the way, the conventional turbine of this type has the following problems. That is, the steam jet 1 that has obtained velocity energy through the steam passage 10 flows into the rotor blade 3 and gives rotational energy to the rotor 4. However, when the wetness of the steam atmosphere is high and the peripheral speed of the moving blade 3 is high, the moving blade 3 may be eroded by the water droplets 7 flowing out from the steam passage 10.
[0005]
Further, the water droplet 7 accumulates on the outer peripheral side A of the stationary blade 2 due to the radial velocity vector due to the centrifugal force added in the previous stage due to large inertia, and the curved surface portion ( (Ventral) Accumulated in B. As a result, damage C caused by the water droplets 7 on the moving blade 3 was concentrated in the vicinity of the outer peripheral side end portion of the moving blade 3 facing the outer peripheral side A of the stationary blade 2.
[0006]
Furthermore, in order to prevent an increase in the wetness of the steam atmosphere, the steam in the middle of expansion in the turbine is taken out and reheated. However, for reheating, the flow path to the boiler and the boiler Since equipment such as a heater is required, the structure is complicated and the cost is increased.
In particular, the low pressure stage L of the turbine uses the large stationary blades 2 and the moving blades 3 as described above. When the low pressure stage L is reached, the steam 1 expands and the pressure becomes low. It was particularly difficult.
[0007]
An object of the present invention is to solve such a conventional problem. A steam ejection hole is provided in a part of the outer peripheral side of the stationary blade, and high-pressure steam is ejected from the steam ejection hole, thereby moistening. It is an object of the present invention to provide a turbine stationary blade that prevents erosion caused by water droplets in steam from occurring on a moving blade.
[0008]
[Means for Solving the Problems]
The invention described in claim 1 is a stationary blade of a turbine, and is configured as follows in order to solve the technical problem described above. That is, a stationary blade of a turbine according to the present invention includes a rotor supported by a turbine casing, a plurality of moving blades attached radially to the outer periphery of the rotor, and a steam passage disposed in the vicinity of the moving blade. A turbine that relatively rotates the rotor by spraying a high-speed steam flow from the steam passage toward the rotor blade,
The stationary blade is formed by attaching a number of nozzle plates in the circumferential direction inside an outer ring, the steam passage is formed between the nozzle plates, and a conical hole formed from the outer ring to the outer periphery of the nozzle plate. A steam ejection hole is formed by the slit that opens into the steam passage following the conical hole, and the slit of the steam ejection hole is located on the upstream side in the vicinity of the throat of the abdomen of the nozzle plate. as well as, it said the inlet of the steam jetting holes to prevent the is formed on the outer periphery of the outer ring, said that by the water droplets in the steam flowing out from the vane erosion occurs in the rotor blade To do.
Here, the “abdominal side” of the stationary blade is the concave curved surface portion side of the stationary blade forming the steam passage, and the “throat portion” indicates a narrow portion of the steam passage formed of the stationary blade. Hereinafter, they are simply referred to as “ventral side” and “throat part”.
[0009]
In the present invention, the turbine can be applied to any type of impulse turbine and reaction turbine. The present invention is preferably applied to a low pressure stage. Moreover, the steam injection hole formed in the outer peripheral side of a stationary blade will not be limited to a specific structure, if it can prevent erosion of a moving blade. In addition, the number of steam ejection holes installed on the stationary blades can be selected as appropriate.
In addition, as long as the stationary blade forms a steam passage that converts the thermal energy of steam into velocity energy, in addition to the partition plate incorporating a large number of nozzle plates, an assembly type in which machined stationary blades are assembled, Includes those formed by welding, casting, etc.
[0010]
The invention according to claim 2 is a turbine stationary blade , and the high-pressure steam before flowing into the stationary blade is formed inside the turbine casing to which the outer peripheral portion of the outer ring is mounted from the inlet side of the steam passage. It is led to the introduction port of the steam ejection hole through a groove.
[0011]
Furthermore, turbine vane of the invention of this third aspect, inlet of the steam ejection hole is connected to passage formed turbines casing, the high-pressure stage of a steam or Mamorutai steam passage It is possible to introduce etc.
[0012]
Further, the turbine vane according to the invention of claim 4 is characterized in that a seal is attached to a connecting portion between the inlet of the steam ejection hole and a passage formed in the turbine casing.
[0013]
[Action]
According to the stationary blade of the turbine according to the first aspect of the present invention, steam is ejected from the steam ejection hole due to the difference between the steam pressure in the steam path and the steam pressure at the inlet of the steam ejection hole, and flows along the steam path. . Then, the drain is subdivided by the shearing force with the steam acceleration flow flowing in the steam passage and flows out of the steam passage. For this reason, even when the wetness of the steam atmosphere is high, water droplets do not accumulate on the outer peripheral side of the stationary blade, and the moving blade is not damaged by erosion.
Further, water droplets are not collected on the outer peripheral side of the stationary blade and are not accumulated on the concave curved surface portion (abdominal side) of the stationary blade due to the bending of the steam passage.
[0014]
According to the second aspect of the present invention, the high-pressure steam before flowing into the steam passage of the stationary blade is immediately introduced into the inlet of the steam ejection hole without passing through a special structure to prevent the erosion of the moving blade due to water droplets. To do.
[0015]
According to the third aspect of the present invention, even in the low pressure stage where the pressure has been lowered due to the expansion of the steam, the stage of the high pressure section or the sanitary steam acts to surely prevent the erosion by the water droplets of the large moving blade. .
Furthermore, according to the fourth aspect of the present invention, high-pressure steam is surely ejected from the steam ejection hole into the steam passage without leaking, and the erosion of the moving blade by water droplets is surely prevented. Further, the turbine casing and the partition plate are centered.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the turbine vane of the present invention will be described in more detail with respect to an embodiment shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention to that unless otherwise specified. It is just an illustrative example.
[0017]
FIG. 1 shows a cross section of a stationary blade and a moving blade according to the first embodiment of the present invention. FIG. 2 shows a cross section of the vapor passage section taken along line II-II in FIG. FIG. 3 shows a cross section of a stationary blade and a moving blade according to the second embodiment. FIG. 4 shows a cross section of the steam passage section taken along line IV-IV in FIG. FIG. 5 shows a partial front view of the partition plate incorporating the stationary blade used in the first embodiment, and FIG. 6 shows a partial front view of the partition plate incorporating the stationary blade used in the second embodiment.
[0018]
(First embodiment)
First, the first embodiment will be described with reference to FIGS. A rotor 4 is rotatably supported in the turbine casing 12. A plurality of blades 3 are attached to the rotor 4 by implanting the blade root 6 in the radial direction on the outer periphery of the rotor 4. A shroud cover 8 is attached to the outer periphery of the moving blade 3 to prevent the steam 1 from leaking from the tip of the moving blade 3.
[0019]
A stationary blade 2 is disposed in the vicinity of the moving blade 3. The stationary blade 2 forms a steam passage 10 as shown in FIG. 2 by attaching a large number of nozzle plates 21 to the inner side of the outer ring 14 in the circumferential direction. The inner side of the stationary blade 2 is attached to the inner ring 15, and the partition plate 5 is configured by the stationary blade 2, the outer ring 14, and the inner ring 15. Further, the inner ring 15 has a nozzle labyrinth formed on the inner periphery, and surrounds the rotor 4 with a clearance 23.
Further, as is clear from FIG. 5, the partition plate 5 is divided into two in the horizontal plane HH, and is attached to the inside of the turbine casing 12 that is also divided into two in the horizontal plane through the groove 17. The
[0020]
As shown in FIGS. 1 and 2, a steam ejection hole 16 is formed on the outer peripheral side of the stationary blade 2. As is apparent from FIG. 1, the steam ejection hole 16 is formed by a conical hole 16a that reaches the nozzle plate 21 from the outer ring 14 of the partition plate 5, and a slit 16b that opens into the steam passage 10 following the conical hole 16a. ing. In the present embodiment, the slit 16 b constituting the vapor ejection hole 16 is open on the upstream side in the vicinity of the throat portion D on the ventral side B of the stationary blade 2. The introduction port 16 c of the steam ejection hole 16 is configured such that the high-pressure steam 1 can be introduced from the inlet side E of the steam passage 10 of the stationary blade 2 through the groove 17.
[0021]
According to the stationary blade of the turbine of this embodiment, first, the high-pressure and high-temperature steam 1 is ejected from the steam passage 10 of the stationary blade 2, and the rotational force indicated by the arrow F is generated in the moving blade 3. The rotor 4 is rotated at a high speed by rotating the rotor blade 3. At that time, steam is ejected from the steam ejection hole 16 due to the difference between the pressure of the high-pressure steam in the steam path 10 and the steam pressure at the inlet 16 c of the steam ejection hole 16, and the drain is blown into the steam path 10.
This drain is subdivided by the shearing force with the accelerated flow of the steam 1 flowing in the steam passage 10 and flows out of the steam passage 10. For this reason, even when the wetness of the steam atmosphere is high, water droplets do not accumulate on the outer peripheral side of the stationary blade 2, and the moving blade 3 is not likely to be damaged by erosion.
[0022]
Further, since the opening of the steam ejection hole 16 into the steam passage 10 is located on the upstream side in the vicinity of the throat D on the ventral side B of the stationary blade 2, the drain ejected from the steam ejection hole 16 has a radius Water droplets that are to be collected on the outer peripheral side A of the stationary blade 2 are reliably removed by the directional velocity vector.
Further, since the high-pressure steam 1 before flowing into the steam passage 10 of the stationary blade 2 is introduced into the introduction port 16c of the steam ejection hole 16, water droplets are reliably removed while the structure is simple.
[0023]
(Second Embodiment)
Next, a stationary blade of a turbine according to the second embodiment will be described based on FIGS. 3, 4 and 6. However, parts having the same structure as in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
[0024]
The partition plate 5 fitted in the turbine casing 12 is provided with a conical hole 16a from the outer ring 14 toward the outer peripheral end of the nozzle plate 21 forming the stationary blade 2, and further, the slit 16b following the conical hole 16a. Is provided, and the slit 16 b is open to the steam passage 10.
The outer ring 14 of the partition plate 5 is formed with an arc-shaped space 18 that is closed inside, and a connecting hole 19 is provided in the space 18, and the space 18 communicates with an appropriate number of steam ejection holes 16. . The inlet 16c of the connection hole 19 is connected to a passage 21 formed in the turbine casing 12, and a piston ring 22 is attached to a connection portion between the connection hole 19 and the passage 21, and the connection portion is It is sealed. Further, the passage 21 is connected to an appropriate high-pressure stage or satellite steam.
[0025]
According to the present embodiment, the steam from the appropriate high-pressure section or the steam from the passage 21 formed in the turbine casing 12 passes through the conical hole 16a of the steam ejection hole 16 and the steam path from the slit 16b. 10 spouts out. Then, the drain is surely blown out into the flow of the steam 1 flowing on the surface of the stationary blade 2, and water droplets in the wet steam are prevented from accumulating on the outer peripheral surface A of the stationary blade 2.
[0026]
Further, since the connecting portion between the inlet 16c of the steam ejection hole 16 and the passage 21 is sealed, the adhesion between the steam ejection hole 16 and the passage 21 of the turbine casing 12 is ensured, and high-pressure steam is prevented from leaking. In addition to preventing it reliably, the partition plate 5 and the turbine casing 12 are centered, and adhesion between the low-pressure side end face and the turbine casing is ensured.
[0027]
【The invention's effect】
As described above, according to the stationary blade of the turbine according to the first aspect of the present invention, the water droplets to be accumulated on the outer peripheral side A of the stationary blade 2 by the radial velocity vector by the steam ejected from the steam ejection hole. It can be reliably removed, and the erosion of the moving blade due to water droplets can be reliably prevented.
Also, since the erosion that occurs in the rotor blades is ubiquitous at the top of the blade, it is sufficient to provide a steam blowout hole to prevent erosion, and the rigidity of the stator blades is not impaired. There is almost no effect on.
Furthermore, since the opening part of the steam outlet hole in the steam passage is located on the upstream side in the vicinity of the ventral throat of the stationary blade, where water droplets are likely to accumulate, accumulation of water drops can be reliably prevented. .
[0028]
According to the turbine vanes of the invention of this second aspect, the inlet of the steam injection holes, the high pressure steam prior to entering the steam path of the vane is introduced, while the structure is simple Water droplets can be reliably removed.
[0029]
According to the turbine vanes of the invention of this third aspect, the inlet of the steam injection holes, by connecting in a passage formed in the turbine casing, leads to high-pressure steam or Mamorutai vapor appropriate stage This ensures that the water droplets are deposited and removed. The effect is particularly remarkable in a low-pressure stage equipped with large stationary blades and moving blades.
[0030]
According to the turbine vanes of the invention of the present claim 4, by mounting a seal connection of a passage formed in the inlet and the turbine casing of a steam injection holes, the steam injection holes and the turbine casing Adhesion with the passage is ensured and leakage of high-pressure steam can be reliably prevented. Further, centering of the stationary blade and the turbine casing is performed, and a highly accurate turbine with good adhesion between the low pressure side end face and the turbine casing can be assembled.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view of a stationary blade and a moving blade according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view of a steam passage and a moving blade taken along line II-II in FIG.
FIG. 3 is a partial cross-sectional view of a stationary blade and a moving blade according to a second embodiment of the present invention.
4 is a cross-sectional view of a steam passage section and a moving blade taken along line IV-IV in FIG. 3;
FIG. 5 is a partial front view of a partition plate incorporating a stationary blade used in the first embodiment.
FIG. 6 is a partial front view of a partition plate incorporating a stationary blade used in the second embodiment.
FIG. 7 is a partial cross-sectional view of a stationary blade and a moving blade of a conventional turbine.
8 is a cross-sectional view of a steam passage and a moving blade taken along line VV in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Steam 2 Stator blade 3 Rotor blade 4 Rotor 7 Water drop 10 Steam passage 12 Turbine casing 16 Steam ejection hole 16a Conical hole 16b Slit 16c Inlet 19 Connection hole 20 Turbine 21 Passage A Outer side of stationary blade B Abdominal side D throat E Steam passage entrance side

Claims (4)

A rotor supported by a turbine casing; a plurality of moving blades radially attached to an outer periphery of the rotor; and a stationary blade disposed in the vicinity of the moving blade to form a steam passage; In the turbine for relatively rotating the rotor by blowing a high-speed steam flow toward the moving blade from
The stationary blade is formed by attaching a number of nozzle plates in the circumferential direction inside an outer ring, the steam passage is formed between the nozzle plates, and a conical hole formed from the outer ring to the outer periphery of the nozzle plate. A steam ejection hole is formed by the slit that opens into the steam passage following the conical hole, and the slit of the steam ejection hole is located on the upstream side in the vicinity of the throat of the abdomen of the nozzle plate. In addition, a turbine is characterized in that the inlet of the steam ejection hole is formed in the outer peripheral portion of the outer ring , and prevents erosion due to water droplets in the steam flowing out from the stationary blade from occurring in the moving blade. Static wings. The high-pressure steam before flowing into the stationary blade is guided from the inlet side of the steam passage to the inlet of the steam ejection hole through a groove formed in the turbine casing in which the outer peripheral portion of the outer ring is mounted. The turbine vane according to claim 1, wherein: 2. The turbine according to claim 1, wherein the inlet of the steam ejection hole is connected to a passage formed in a turbine casing, and high-pressure stage steam or satellite steam can be introduced into the passage. Static wings. The turbine vane according to claim 3, wherein a seal is attached to a connecting portion between the inlet of the steam ejection hole and a passage formed in the turbine casing .

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