JP6178273B2 - Steam turbine - Google Patents

Description

  Embodiments of the present invention relate to a steam turbine.

  From the viewpoint of improving the efficiency of steam turbines, steam turbines using mainstream steam having a temperature of about 600 ° C. are currently in practical use. In order to further improve the efficiency of the steam turbine, the temperature of the mainstream steam is considered to be about 700 to 750 ° C., and development is being promoted.

  In such a steam turbine, since the mainstream steam is high temperature, some components need to be made of a heat-resistant alloy. However, heat resistant alloys are expensive. Therefore, for example, in a turbine rotor, a configuration in which a portion where the temperature is relatively low is made of a conventional material, a portion where the temperature is high is made of a heat resistant alloy, and the conventional material and the heat resistant alloy are connected by welding is studied. ing.

JP 2009-144650 A

  The strength of the joint between the above-described conventional material and the heat-resistant alloy is approximately the same as that of the conventional material or slightly inferior to the conventional material. For this reason, the joint portion must be configured at a position that becomes a temperature region where the strength can be maintained. In this case, in the steam turbine in which the steam temperature is increased, there are many portions made of a heat-resistant alloy. Considering the cost of welding, using a turbine rotor in which a conventional material and a heat-resistant alloy are welded may increase the cost.

  In addition, when the joint is exposed to high-temperature steam due to some trouble, there is a risk of insufficient strength.

  The problem to be solved by the present invention is to provide a steam turbine that can accurately cool a joint portion in a turbine rotor that is welded and can suppress an increase in temperature of the joint portion.

The steam turbine according to the embodiment includes a turbine rotor configured by joining a cylindrical first rotor body and a cylindrical second rotor body in the turbine rotor axial direction , and the outer periphery of the turbine rotor on the outer periphery of the turbine rotor. A steam seal portion provided with a gap from the turbine rotor is provided . The first rotor barrel before SL has a central through hole formed in the axial center of the first rotor body portion, provided on the first rotor body portion, the cooling steam introduced in communication with the central through-hole Formed between the hole, the cooling steam introduction hole, and the joint between the first rotor body and the second rotor body, and in the vicinity of the joint and in the first rotor body An opening is provided on the outer peripheral surface, and a cooling steam jet hole communicating with the central through hole is provided. The joint portion is opposed to the steam seal portion, and the opening of the cooling steam ejection hole is opposed to the steam seal portion, and cooling steam is ejected from the opening into the gap between the turbine rotor and the steam seal portion. To do .

It is a figure which shows the longitudinal cross-section (meridian cross section) containing the central axis of a turbine rotor of the steam turbine of 1st Embodiment. It is an expanded sectional view for explaining the composition of the cooling steam injection hole in the turbine rotor of the steam turbine of a 1st embodiment. It is the figure which showed the AA cross section of FIG. FIG. 4 is a cross section corresponding to the cross section of FIG. 3 showing a part of the steam turbine of the first embodiment, and showing a cross section along the central axis of a cooling steam ejection hole. It is a figure which shows the longitudinal cross-section (meridian cross section) containing the central axis of a turbine rotor of the steam turbine of 2nd Embodiment. It is a figure which shows the longitudinal cross-section (meridian cross section) containing the central axis of a turbine rotor of the steam turbine of the other structure in 2nd Embodiment.

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

(First embodiment)
FIG. 1 is a diagram illustrating a cross section (meridian cross section) including a central axis of a turbine rotor 24 of the steam turbine 10 according to the first embodiment. FIG. 2 is an enlarged cross-sectional view for explaining the configuration of the cooling steam ejection holes 45 in the turbine rotor 24 of the steam turbine 10 according to the first embodiment. FIG. 3 is a view showing a cross section taken along the line AA of FIG.

  In the following, an intermediate pressure turbine will be described as an example of the steam turbine 10, but the configuration of the present embodiment is also applied to a high pressure turbine to which high-temperature and high-pressure steam is supplied, and also to an ultra-high pressure turbine. Can do.

  As shown in FIG. 1, a turbine rotor 24 is provided through the casing 20. On the wheel portion 53 of the turbine rotor 24, the moving blade 25 is implanted in the circumferential direction to constitute a moving blade cascade.

  A diaphragm outer ring 21 is provided on the inner periphery of the casing 20 along the circumferential direction. Inside the diaphragm outer ring 21, a diaphragm inner ring 22 is provided along the circumferential direction. A plurality of stationary blades 23 are supported in the circumferential direction between the diaphragm outer ring 21 and the diaphragm inner ring 22 to constitute a stationary blade cascade. The stationary blade cascade is provided in the axial direction of the turbine rotor 24 alternately with the moving blade cascade. And the some turbine stage which consists of a stationary blade cascade and a moving blade cascade is comprised.

  A labyrinth seal 33 is provided on the inner periphery of the diaphragm inner ring 22 to suppress the leakage of steam from between the diaphragm inner ring 22 and the turbine rotor 24. A plurality of gland labyrinth seals 26 are provided along the turbine rotor axial direction on the inner periphery of the casing 20 on the outer side (left side in FIG. 1) than the position where the first stage rotor blades 25 are provided. Leakage of steam to the outside between the casing 20 and the turbine rotor 24 is prevented.

  Further, the steam turbine 10 is provided with a steam inlet pipe 30 so as to communicate the casing 20. Steam from the outside is introduced into the steam turbine 10 by the steam inlet pipe 30 and introduced into the steam flow path 31 as main steam.

  Next, the configuration of the turbine rotor 24 will be described.

  As shown in FIG. 1, the turbine rotor 24 is configured by joining two rotor body portions 40 and 50 in the turbine rotor axial direction, for example, by welding.

  As shown in FIG. 1, the rotor body 40 constitutes, for example, the turbine rotor 24 on the outer side (left side in FIG. 1) than the position of the first stage stationary blade cascade. Therefore, the rotor body 40 is not exposed to high-temperature steam and can be made of conventional steel such as CrMoV steel, for example. The rotor body 40 functions as a first rotor body.

  The rotor body 40 has a cylindrical shape. A recess 42 is formed at the center of the joint end surface 41 of the rotor body 40. The recess 42 is formed such that a cross-sectional shape perpendicular to the turbine rotor shaft is, for example, a circle. For example, the recess 42 can be formed so that the cross-sectional shape is substantially the same in any cross-section. That is, the recess 42 is, for example, a cylindrical cavity having a constant cross-sectional diameter.

  A central through-hole 43 whose one end communicates with the recess 42 is formed in the axial center of the rotor body 40 over the axial direction. The other end of the center through hole 43 is configured to be sealable in order to prevent the cooling steam introduced into the center through hole 43 from flowing out. The other end of the central through hole 43 is sealed with, for example, a sealing plate fixed through a flange.

  The rotor body 40 is formed with a cooling steam introduction hole 44 having an opening 44 a on the outer peripheral surface and communicating with the central through hole 43. For example, the cooling steam introduction holes 44 are configured by through holes that penetrate radially in the radial direction of the rotor body 40 and are formed at a plurality of locations in the circumferential direction. Cooling steam is introduced into the central through-hole 43 through the cooling steam introduction hole 44.

  A cooling steam injection hole 45 is formed between the cooling steam introduction hole 44 and the joint 60 between the rotor body 40 and the rotor body 50. The cooling steam ejection hole 45 has an opening 45 a on the outer peripheral surface of the rotor body 40 and communicates with the central through hole 43. The opening 45 a is located in the vicinity of the joint portion 60.

  Here, the vicinity of the joint portion 60 where the opening 45a is located will be described. As shown in FIG. 2, a heat affected zone 61 affected by heat in welding exists around the joint 60. The heat-affected zone 61 is a portion in which the structure is changed by heat from welding. Therefore, characteristics such as mechanical strength of the heat affected zone 61 and the base material are different. It is preferable to avoid the formation of a part of the cooling steam ejection hole 45 in the heat affected zone 61 in order to maintain the strength, for example.

  Therefore, the vicinity of the junction 60 where the opening 45a is located means the vicinity of the junction 60 avoiding the heat affected zone 61 as shown in FIG. Specifically, on the outer peripheral surface of the rotor body 40, the distance between the end of the opening 45a on the heat affected zone 61 side and the end of the heat affected zone 61 on the opening 45a side is 5 mm to 20 mm. Is preferred. The opening 45a is formed at a position facing the labyrinth seal 33 and a later-described ground labyrinth seal 26, or at a position not facing the labyrinth seal 33 and the ground labyrinth seal 26.

  Further, the cooling steam ejection hole 45 is inclined in the turbine rotor axial direction in the cross section shown in FIGS. 1 and 2. For example, as shown in FIG. 3, the cooling steam ejection holes 45 are configured by through holes that penetrate radially, and are formed at a plurality of locations in the circumferential direction. Here, an example is shown in which the cooling steam ejection holes 45 are not inclined in the circumferential direction. The cooling steam is ejected from the opening 45a to the vicinity of the joint 60 through the cooling steam ejection hole 45, and the joint 60 is cooled.

  The flow rate of the cooling steam is adjusted by, for example, the number of cooling steam ejection holes 45 and the hole diameter. Moreover, the pressure loss in the cooling steam ejection hole 45 can be changed by changing the length of the cooling steam ejection hole 45 according to the inclination angle in the turbine rotor axial direction. Thereby, the ejection flow rate of the cooling steam can be adjusted.

  As shown in FIG. 1, the rotor body 50 constitutes the turbine rotor 24 on the inner side (right side in FIG. 1) than the position of the first stage stationary blade cascade. As a result, the rotor body 50 is exposed to high-temperature steam and becomes high temperature. For example, the rotor body 50 is made of heat-resistant steel such as 12Cr steel or heat-resistant alloy such as Ni-based alloy. The rotor body 50 functions as a second rotor body.

  The rotor body 50 has a cylindrical shape. A recess 52 is formed at the center of the joint end surface 51 of the rotor body 50. The recess 52 is formed such that a cross-sectional shape perpendicular to the turbine rotor shaft is, for example, a circle. For example, the recess 52 can be formed so that the cross-sectional shape is substantially the same in any cross-section. That is, the recess 52 is, for example, a cylindrical cavity having a constant cross-sectional diameter. In addition, the hollow part which consists of the hollow part 42 and the hollow part 52 is comprised by joining the joint end surface 41 and the joint end surface 51. FIG.

  The joint end surface 51 of the rotor body 50 is configured in a shape corresponding to the joint end surface 41 of the rotor body 40, and for example, it is preferable that both the joint end surfaces 41 and 51 have the same shape.

  The rotor body portion 50 includes a wheel portion 53 formed over the circumferential direction so as to protrude outward in the radial direction. The wheel portion 53 is formed in a plurality of stages in the turbine rotor axial direction. As described above, the rotor blades 25 are implanted in the wheel portion 53.

  On the inner wall (inner surface) of the casing 20 facing the opening 44a of the cooling steam introduction hole 44 formed in the rotor body 40, a concave groove 27 is formed in the circumferential direction as shown in FIG. . A gland labyrinth seal 26 is provided on the outer side (left side in FIG. 1) and the inner side (right side in FIG. 1) than the groove portion 27. That is, the ground labyrinth seal 26 is provided on the inner wall of the casing 20 so as to sandwich the groove 27 in the turbine rotor axial direction. The gland labyrinth seal 26 sandwiching the groove 27 prevents leakage of steam to the outside and suppresses the cooling steam introduced into the groove 27 from leaking to the surroundings. The ground labyrinth seal 26 functions as a steam seal portion.

  The casing 20 is formed with a communication hole 29 that communicates with a cooling steam supply pipe 28 that supplies cooling steam and guides the cooling steam to the groove 27. The communication holes 29 are preferably formed at a plurality of locations in the circumferential direction, for example, in order to uniformly supply the cooling steam to the groove portion 27 over the circumferential direction. The communication hole 29 functions as a cooling steam supply channel.

  As the cooling steam, steam extracted from another steam turbine, steam exhausted from another steam turbine, steam extracted from a boiler, or the like can be used. When the steam turbine 10 is an intermediate pressure turbine, for example, steam extracted from a high-pressure turbine can be used as the cooling steam. When the steam turbine 10 is a high-pressure turbine, for example, steam extracted from a boiler can be used as the cooling steam.

  Note that the temperature of the cooling steam is preferably set to a temperature at which a large thermal stress is not generated in the components such as the turbine rotor 24 to be cooled. The temperature of the cooling steam can be changed according to the specifications of the steam turbine that supplies the cooling steam, and can be set to about 300 ° C., for example.

  The supply pressure of the cooling steam is set such that the pressure of the cooling steam at the opening 45a of the cooling steam ejection hole 45 is higher than the pressure in the space near the joint 60 where the cooling steam is ejected. That is, the supply pressure of the cooling steam is set to such an extent that the cooling steam can be reliably jetted from the cooling steam jet hole 45 into the space in the vicinity of the joint portion 60.

  Next, the operation of the steam turbine 10 having the cooling structure as described above will be described.

  As shown in FIG. 1, the steam introduced from the steam inlet pipe 30 into the steam turbine 10 is guided to the first stage stationary blade 23 and ejected toward the first stage moving blade 25. Then, the steam flows through the steam flow path 31 including the stationary blade 23 and the moving blade 25, and rotates the turbine rotor 24 while performing expansion work. The steam that has passed through the final stage moving blade 25 is exhausted from the steam turbine 10 through an exhaust passage (not shown).

  In addition, since the intermediate pressure turbine is illustrated here, the steam exhausted from the steam turbine 10 is introduced into the low pressure turbine. For example, when the steam turbine 10 is a high pressure turbine, the steam passes through the reheat boiler and is introduced into the intermediate pressure turbine.

  The cooling steam introduced from the cooling steam supply pipe 28 into the groove portion 27 through the communication hole 29 passes through the cooling steam introduction hole 44 and is guided to the central through hole 43. At this time, since the other end side of the central through hole 43 is sealed by a sealing member (not shown), the cooling steam does not flow out from the other end of the central through hole 43.

  The cooling steam guided to the central through hole 43 flows into the cooling steam ejection hole 45. The cooling steam that has flowed into the cooling steam ejection hole 45 is ejected from the opening 45 a to the vicinity of the joint portion 60. The jetted cooling steam flows downstream between the labyrinth seal 33 and the turbine rotor 24 while cooling the vicinity of the joint 60 and the joint 60.

  At this time, the cooling steam contacts the surface of the joint 60 and directly cools the joint 60. Further, the joint 60 is also cooled by the cooling steam passing through the cooling steam ejection holes 45. When the cooling steam passes through the cooling steam introduction hole 44, the central through hole 43, and the cooling steam ejection hole 45, the turbine rotor 24 is also cooled.

  The cooling steam that has flowed downstream between the labyrinth seal 33 and the turbine rotor 24 flows along the surfaces of the turbine rotor 24 and the wheel portion 53. Thereby, the turbine rotor 24 and the wheel part 53 are cooled. The cooling steam that flows along the surface of the wheel portion 53 flows into the steam flow path 31 from between the diaphragm inner ring 22 and the moving blade 25.

  As described above, according to the steam turbine 10 of the first embodiment, the cooling steam is once introduced into the turbine rotor 24, and the cooling steam is ejected from the cooling steam ejection hole 45 to the vicinity of the joint portion 60. Can do. Therefore, the vicinity of the joint portion 60 and the joint portion 60 can be accurately cooled, and the temperature rise of the joint portion 60 can be suppressed.

  In addition, by appropriately cooling the joint portion 60, for example, the joint portion 60 can be provided on the higher temperature side than the conventional one. Thereby, the part comprised with an expensive heat-resistant alloy can be reduced.

  Here, the configuration of the cooling steam ejection hole 45 described above is not limited to the configuration described above. 4 is a cross section corresponding to the cross section of FIG. 3 showing a part of the steam turbine 10 of the first embodiment, and showing a cross section along the central axis of the cooling steam jet hole 45.

  The cooling steam ejection holes 45 may be inclined in the turbine rotor axial direction and may be inclined in the circumferential direction as shown in FIG. In this case, the cooling steam ejection hole 45 is preferably inclined in the rotational direction of the turbine rotor 24 (the arrow direction in FIG. 4), but may be inclined in the direction opposite to the rotational direction of the turbine rotor 24.

  Moreover, the pressure loss in the cooling steam ejection hole 45 can be changed by changing the length of the cooling steam ejection hole 45 according to the inclination angle of the turbine rotor axial direction or the circumferential direction. Thereby, the ejection flow rate of the cooling steam can be adjusted.

(Second Embodiment)
FIG. 5 is a view showing a longitudinal section (meridional section) including the central axis of the turbine rotor 24 of the steam turbine 11 according to the second embodiment. In addition, the same code | symbol is attached | subjected to the component same as the steam turbine 10 of 1st Embodiment, and the overlapping description is abbreviate | omitted or simplified.

  In the steam turbine 11 of the second embodiment, the configurations of the steam turbine 10 and the turbine rotor 24 of the first embodiment are different. Therefore, here, the configuration of the different turbine rotor 24 will be mainly described.

  The turbine rotor 24 is configured by joining three rotor body portions 70, 80, 90 in this order in the turbine rotor axial direction, for example, by welding.

  As shown in FIG. 5, the rotor body 70 forms, for example, the turbine rotor 24 on the outer side (left side in FIG. 5) with respect to the position of the first stage stationary blade cascade. Therefore, the rotor body 70 is not exposed to high-temperature steam, and can be made of conventional steel such as CrMoV steel, for example. The rotor body 70 functions as a first rotor body.

  The rotor body 70 has a cylindrical shape. A recess 72 is formed at the center of the joint end surface 71 of the rotor body 70. The recess 72 is formed so that a cross-sectional shape perpendicular to the turbine rotor shaft is, for example, a circle. For example, the recess 72 can be formed so that the cross-sectional shape is substantially the same in any cross-section. That is, the recess 72 is, for example, a cylindrical cavity having a constant cross-sectional diameter.

  A central through-hole 73 whose one end communicates with the recess 72 is formed in the axial center of the rotor body 70 in the axial direction. The other end of the center through hole 73 is configured to be sealable in order to prevent the cooling steam introduced into the center through hole 73 from flowing out. The other end of the center through hole 73 is sealed with, for example, a sealing plate fixed via a flange. The center through hole 73 functions as a first center through hole.

  The rotor body 70 has an opening 74 a on the outer peripheral surface, and a cooling steam introduction hole 74 that communicates with the central through hole 73 is formed. The cooling steam introduction holes 74 are constituted by, for example, through holes that penetrate radially in the radial direction of the rotor body 70 and are formed at a plurality of locations in the circumferential direction. Cooling steam is introduced into the central through hole 73 through the cooling steam introduction hole 74.

  As shown in FIG. 5, the rotor body 80 constitutes the turbine rotor 24 on the inner side (right side in FIG. 5) than the position of the first stage stationary blade cascade. As a result, the rotor body 80 is exposed to high-temperature steam and becomes high temperature, so that the rotor body 80 is made of heat-resistant steel such as 12Cr steel or heat-resistant alloy such as Ni-based alloy, for example. The rotor body 80 functions as a second rotor body.

  The rotor body 80 has a cylindrical shape. A recess 82 is formed at the center of one joint end surface 81 of the rotor body 80. A recess 84 is formed at the center of the other joining end surface 83 of the rotor body 80. These hollow portions 82 and 84 are formed so that a cross-sectional shape perpendicular to the turbine rotor shaft is, for example, a circle. For example, the depressions 82 and 84 can be formed so that the cross-sectional shape is substantially the same in any cross-section. That is, the depressions 82 and 84 are, for example, cylindrical cavities having a constant cross-sectional diameter.

  The joint end surface 81 of the rotor body 80 is configured to have a shape corresponding to the joint end surface 71 of the rotor body 70, and for example, it is preferable that both the joint end surfaces 71 and 81 have the same shape. Further, the joint end surface 83 of the rotor body 80 is configured to have a shape corresponding to a joint end surface 91 of the rotor body 90 described later. For example, both the joint end surfaces 83 and 91 are configured to have the same shape. It is preferable.

  The rotor body 70 and the rotor body 80 are joined by welding or the like to form the joint 100. In addition, the hollow part which consists of the hollow part 72 and the hollow part 82 is comprised by joining these. Further, the rotor body 80 and the rotor body 90 are joined by welding or the like to constitute the joint 101. In addition, the hollow part which consists of the hollow part 84 and the hollow part 92 mentioned later is comprised by joining these.

  A central through hole 85 having one end communicating with the recess 82 and the other end communicating with the recess 84 is formed at the axial center of the rotor body 80. The central through hole 85 functions as a second central through hole.

  The rotor body portion 80 includes a wheel portion 86 formed over the circumferential direction so as to protrude outward in the radial direction. The wheel portion 86 is formed in a plurality of stages in the turbine rotor axial direction. At the tip of the wheel portion 86, the moving blade 25 is implanted in the circumferential direction to constitute a moving blade cascade.

  Further, the rotor body 80 is formed with a cooling steam ejection hole 87. The cooling steam ejection hole 87 has an opening 87 a on the outer peripheral surface of the rotor body 80 and communicates with the central through hole 85. The opening 87 a is located in the vicinity of the joint portion 101. The vicinity of the joint portion 101 where the opening 87a is formed is synonymous with the vicinity of the joint portion 60 where the opening 45a is formed in the first embodiment.

  Here, the opening 87 a is formed on the outer peripheral surface of the rotor body 80 between the wheel portions 86. The opening 87a may be a position facing the labyrinth seal 33 or a position not facing the opening 87a.

  The cooling steam ejection holes 87 are inclined in the turbine rotor axial direction in the cross section shown in FIG. Here, an example in which the cooling steam ejection hole 87 is not inclined in the circumferential direction is shown. Note that, as shown in FIG. 4 of the first embodiment, the cooling steam ejection hole 87 may be inclined in the turbine rotor axial direction and may be inclined in the circumferential direction.

  For example, as shown in FIG. 5, the cooling steam ejection holes 87 are configured by through holes that penetrate radially, and are formed at a plurality of locations in the circumferential direction. The cooling steam is ejected from the opening 87a to the vicinity of the joint portion 101 through the cooling steam ejection hole 87, and the joint portion 101 is cooled.

  The cooling steam ejection flow rate is adjusted by, for example, the number of cooling steam ejection holes 87 and the hole diameter. Moreover, the pressure loss in the cooling steam ejection hole 87 can be changed by changing the length of the cooling steam ejection hole 87 according to the inclination angle in the turbine rotor axial direction. Thereby, the ejection flow rate of the cooling steam can be adjusted.

  As shown in FIG. 5, the rotor body 90 constitutes the turbine rotor 24 on the downstream side (right side in FIG. 5) of the rotor body 90. As a result, the rotor body 90 is exposed to high-temperature steam and becomes high temperature. For example, the rotor body 90 is made of heat-resistant steel such as 12Cr steel or heat-resistant alloy such as Ni-based alloy. For example, the rotor body 90 may be made of the same material as that of the rotor body 80 or may be made of a different material. The rotor body 90 functions as a third rotor body.

  The rotor body 90 has a cylindrical shape. A recess 92 is formed at the center of the joint end surface 91 of the rotor body 90. The recess 92 is formed so that a cross-sectional shape perpendicular to the turbine rotor shaft is, for example, a circle. For example, the recess 92 can be formed so that the cross-sectional shape is substantially the same in any cross-section. That is, the hollow portion 92 is, for example, a cylindrical hollow portion having a constant cross-sectional diameter.

  Similar to the rotor body 80, the rotor body 90 includes a wheel portion 93 formed in the circumferential direction so as to protrude outward in the radial direction. The configuration of the wheel portion 93 is the same as the configuration of the wheel portion 53 in the rotor body portion 80.

  As shown in FIG. 5, a concave groove 27 is formed in the inner wall (inner surface) of the casing 20 facing the opening 74a of the cooling steam introduction hole 74 formed in the rotor body 70, as shown in FIG. . In addition, the structure of the groove part 27 is as having demonstrated in 1st Embodiment.

  Here, the supply pressure of the cooling steam is set so that the pressure of the cooling steam at the opening 87a of the cooling steam ejection hole 87 is higher than the pressure of the space in the vicinity of the joint portion 101 from which the cooling steam is ejected. That is, the supply pressure of the cooling steam is set to such an extent that the cooling steam can be reliably jetted from the cooling steam jetting hole 87 into the space in the vicinity of the joint portion 101.

  Next, the operation of the steam turbine 11 having the above-described cooling structure will be described. The flow of main steam is as described in the first embodiment.

  The cooling steam introduced from the cooling steam supply pipe 28 into the groove portion 27 through the communication hole 29 passes through the cooling steam introduction hole 74 and is guided to the central through hole 73. At this time, since the other end side of the center through hole 73 is sealed by a sealing member (not shown), the cooling steam does not flow out from the other end of the center through hole 73.

  The cooling steam guided to the center through hole 73 is guided to the center through hole 85 and flows into the cooling steam ejection hole 87. The cooling steam that has flowed into the cooling steam ejection hole 87 is ejected in the vicinity of the joint portion 101 from the opening 87a. Part of the jetted cooling steam flows into the steam flow path 31 from between the diaphragm inner ring 22 and the moving blade 25. The remainder of the jetted cooling steam flows downstream between the labyrinth seal 33 and the turbine rotor 24, and then flows into the steam flow path 31 from between the diaphragm inner ring 22 and the moving blade 25.

  At this time, the cooling steam contacts the surface of the joint portion 101 and directly cools the joint portion 101. The joint 101 is also cooled by the cooling steam passing through the cooling steam ejection hole 87. When the cooling steam passes through the cooling steam introduction hole 74, the central through holes 73 and 85, and the cooling steam ejection hole 87, the turbine rotor 24 is also cooled.

  As described above, according to the steam turbine 11 of the second embodiment, the cooling steam is once introduced into the turbine rotor 24, and the cooling steam is ejected from the cooling steam ejection hole 87 to the vicinity of the joint portion 101. Can do. Therefore, the vicinity of the joint portion 101 and the joint portion 101 can be accurately cooled, and the temperature rise of the joint portion 101 can be suppressed.

  Here, the configuration of the steam turbine 11 of the second embodiment is not limited to the configuration described above. FIG. 6 is a view showing a longitudinal section (meridional section) including the central axis of the turbine rotor 24 of the steam turbine 11 having another configuration according to the second embodiment.

  As shown in FIG. 6, a cooling steam ejection hole 110 may be formed between the cooling steam introduction hole 74 and the joint portion 100. The cooling steam ejection hole 110 has an opening 110 a on the outer peripheral surface of the rotor body 70 and communicates with the central through hole 73. The opening 110 a is located in the vicinity of the joint portion 100. The vicinity of the joint portion 100 where the opening 110a is formed is synonymous with the vicinity of the joint portion 60 where the opening 45a is formed in the first embodiment.

  Further, the cooling steam ejection hole 110 is inclined in the turbine rotor axial direction in the cross section shown in FIG. 6. Here, an example is shown in which the cooling steam ejection holes 110 are not inclined in the circumferential direction. As shown in FIG. 4 of the first embodiment, the cooling steam ejection hole 110 may be inclined in the turbine rotor axial direction and may be inclined in the circumferential direction. The cooling steam ejection hole 110 functions as a second cooling steam ejection hole.

  For example, as shown in FIG. 6, the cooling steam ejection holes 110 are configured by through holes that penetrate radially, and are formed at a plurality of locations in the circumferential direction. The cooling steam is jetted from the opening 110a to the vicinity of the joint 100 through the cooling steam jet hole 110, and the joint 100 is cooled.

  Here, in the flow of the cooling steam, it is preferable that the pressure loss in the cooling steam ejection hole 110 is smaller than the pressure loss in the cooling steam ejection hole 87. The pressure of the space where the cooling steam is ejected by the cooling steam ejection hole 110 is higher than the pressure of the space where the cooling steam is ejected by the cooling steam ejection hole 87. Therefore, the predetermined flow rate of the cooling steam ejected from the cooling steam ejection hole 110 can be maintained by making the pressure loss in the cooling steam ejection hole 110 smaller than the pressure loss in the cooling steam ejection hole 87.

  The pressure loss in the cooling steam ejection hole 110 is made smaller than the pressure loss in the cooling steam ejection hole 87. For example, when the diameters of the respective holes are the same, the passage length of the cooling steam ejection hole 110 is reduced. This can be realized by making the passage length shorter than 87. For example, the respective passage lengths can be adjusted by changing the inclination angle of the cooling steam ejection hole 110 and the cooling steam ejection hole 87 in the turbine rotor axial direction. In addition, not only this method but each pressure loss may be adjusted by changing a hole diameter, a number, etc., for example.

  In the steam turbine 11 shown in FIG. 6, the vicinity of the joint portion 101 and the joint portion 101 can be accurately cooled, and the vicinity of the joint portion 100 and the joint portion 100 can be accurately cooled.

  Further, by appropriately cooling the joint portion 100, for example, the joint portion 100 can be provided on the higher temperature side than the conventional one. Thereby, the part comprised with an expensive heat-resistant alloy can be reduced.

  According to the embodiment described above, it is possible to accurately cool the joint in the turbine rotor that has been welded and to suppress the temperature rise of the joint.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 10, 11 ... Steam turbine, 20 ... Casing, 21 ... Diaphragm outer ring, 22 ... Diaphragm inner ring, 23 ... Stator blade, 24 ... Turbine rotor, 25 ... Moving blade, 26 ... Grand labyrinth seal, 27 ... Groove, 28 ... Cooling steam Supply pipe, 29 ... communication hole, 30 ... steam inlet pipe, 31 ... steam flow path, 33 ... labyrinth seal, 40, 50, 70, 80, 90 ... rotor body, 41, 51, 71, 81, 83, 91 ... Join end face, 42, 52, 72, 82, 84, 92 ... Depression, 43, 73, 85 ... Center through hole, 44, 74 ... Cooling steam introduction hole, 45, 87, 110 ... Cooling steam ejection hole, 44a 45a, 74a, 87a, 110a ... opening, 53, 93 ... wheel part, 60 ... joint part, 61 ... heat affected part, 86 ... wheel part, 100, 101 ... joint part.

Claims (9)

Cylindrical shaped first rotor body portion and a cylindrical second rotor body portion and a configured by joining the turbine rotor axial direction the turbine rotor, and the turbine rotor and the gap on the outer periphery of the turbine rotor Contact A steam turbine having a steam seal portion provided,
The first rotor body is
A central through hole formed in the axial center of the first rotor body;
A cooling steam introduction hole provided in the first rotor body and communicating with the central through hole;
It is formed between the cooling steam introduction hole and the joint between the first rotor body and the second rotor body, and in the vicinity of the joint and on the outer peripheral surface of the first rotor body. A cooling steam ejection hole having an opening and communicating with the central through hole ,
The joint portion faces the steam seal portion, and the opening of the cooling steam ejection hole faces the steam seal portion, and the cooling steam is ejected from the opening into the gap between the turbine rotor and the steam seal portion. A steam turbine characterized by   The steam turbine according to claim 1, wherein the cooling steam ejection hole is inclined in the turbine rotor axial direction. Cylindrical shaped first rotor body portion and a cylindrical second rotor body portion and a cylindrical third rotor barrel and the turbine rotor is formed by joining in this order on the turbine rotor axial direction, and the A steam turbine provided with a steam seal portion provided on the outer periphery of the turbine rotor with a gap from the turbine rotor ,
The first rotor body is
A first central through hole formed at the axial center of the first rotor body;
A cooling steam introduction hole provided in the first rotor body and communicating with the first central through hole;
The second rotor body is
A second central through hole formed at the axial center of the second rotor body and communicating with the first central through hole;
Has an opening on the outer peripheral surface of the near and the second rotor body portion of the joint portion between said second rotor body part the third rotor barrel, cooling steam which communicates with the second central through-hole With a jet hole ,
The joint portion faces the steam seal portion, and the opening of the cooling steam ejection hole faces the steam seal portion, and the cooling steam is ejected from the opening into the gap between the turbine rotor and the steam seal portion. A steam turbine characterized by   The steam turbine according to claim 3, wherein the cooling steam ejection hole is inclined in the turbine rotor axial direction. It is formed between the cooling steam introduction hole and the joint between the first rotor body and the second rotor body, and in the vicinity of the joint and on the outer peripheral surface of the first rotor body. 5. The steam turbine according to claim 3, further comprising a second cooling steam ejection hole having an opening and communicating with the first central through hole.   The steam turbine according to claim 5, wherein the second cooling steam ejection hole is inclined in the turbine rotor axial direction.   The steam turbine according to claim 5 or 6, wherein in the flow of the cooling steam, the pressure loss in the second cooling steam ejection hole is smaller than the pressure loss in the cooling steam ejection hole. A groove formed in the circumferential direction on the inner wall of the casing facing the opening of the cooling steam introduction hole formed on the outer peripheral surface of the first rotor body ;
A second steam seal portion provided on the inner wall of the casing so as to sandwich the groove portion in the turbine rotor axial direction;
The steam turbine according to any one of claims 1 to 7, further comprising: a cooling steam supply passage formed in the casing and guiding the cooling steam introduced from the outside to the groove portion.   The steam turbine according to any one of claims 1 to 8, wherein the first rotor body and the second rotor body are made of different materials.

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