JP3746736B2 - Steam turbine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a steam turbine, and more particularly, to a steam turbine that includes a shield that shields heat transfer from steam to a passenger compartment, and includes means for suppressing erosion due to the steam flow of the shield.
[0002]
[Prior art]
Steam turbines with a shield that shields heat transfer from the steam to the passenger compartment are now known. As such a steam turbine, a technique described in JP-A-6-129207 is known. FIG. 5 is a side cross-sectional view showing an overall configuration of a conventional steam turbine, and FIG. 6 is a cross-sectional view taken along line A showing a main part of the steam turbine shown in FIG. The steam turbine 100 includes an impeller 101, a high-pressure turbine 102, an intermediate-pressure turbine 103, and a casing 110 that accommodates them. The vehicle compartment 110 can be divided into an upper vehicle compartment 110a and a lower vehicle compartment 110b in the horizontal direction, and is configured by bolting 112 with flange portions 111 and 111 (see FIG. 6). Further, the steam turbine 100 includes a cast dummy 120 on the outer periphery of the impeller 101. The dummy 120 is a cylindrical member that partitions the high-pressure turbine 102 and the intermediate-pressure turbine 103 and suppresses internal leakage of steam in the vehicle interior 110. The dummy 120 is a so-called nozzle chamber-integrated dummy 120 that forms part of the steam flow path wall on the intermediate pressure turbine 103 side and the nozzle chamber 104 on the high-pressure turbine 102 side. .
[0003]
Further, four high pressure nozzles 113 and four medium pressure nozzles 114 are formed on the outer periphery of the casing 110 so as to protrude from the outside, and constitute steam inlets 115 and 116 from the outside to the interior of the casing 110. (See FIG. 6). FIG. 7 is an enlarged cross-sectional view illustrating a main part of the steam turbine 100 illustrated in FIG. 6, and FIG. 8 is a cross-sectional view taken along the line BB of the steam turbine 100 illustrated in FIG. 6. A steam chamber 106 that distributes the introduced steam evenly to the steam passage 105 is formed inside the vehicle compartment 110, and an inlet 115 of the intermediate pressure nozzle 114 communicates with the steam chamber 106. The steam chamber 106 is provided with a shield 130 formed by processing an iron plate into a sheet metal.
[0004]
The shield 130 includes an annular main body 131, a tubular sleeve 132 welded to the side surface of the main body 131, and a back surface 133 formed on one edge of the main body 131 (see FIG. 9). . The shield 130 is installed by inserting the sleeve 132 into the intermediate pressure tube base 114 from the inside of the passenger compartment 110 and the cuff 135 against the stepped portion 139 provided on the inner periphery of the intermediate pressure tube base 114. The shield 130 is installed with the main body 131 moored by a pin 140 while providing a gap 134 between the inner wall of the passenger compartment 110. Thereby, the shield 130 covers the inner wall 107 of the passenger compartment 110 and shields heat conduction from the steam. An annular seal member 136 is sandwiched in a gap 134 between the outer periphery of the cuff 135 of the sleeve portion 132 and the inner periphery of the inlet portion 115 of the intermediate pressure tube base 114 to suppress convection between the internal steam and the steam in the gap 134. (See FIG. 7). In addition, seal members 137 a and 137 b are also sandwiched between the outer periphery of the main body 131 and the back surface 133 to seal the gap 134. The vehicle compartment 110 is assembled after the shield 130 is moored to the inner wall 107.
[0005]
In this conventional steam turbine 100, steam is introduced into the vehicle compartment 110 from the inlet portion 115 of the intermediate pressure nozzle 114 and flows into the steam chamber 106 through the sleeve portion 132 of the shield 130. At this time, the shield 130 covers the inner wall 107 of the passenger compartment 110 and shields heat transfer from the steam to the passenger compartment 110. As a result, thermal deformation of the passenger compartment 110 is suppressed to prevent the bolt 112 from creeping, and problems such as steam leakage due to a decrease in tightening force have been solved. The steam then flows from the steam chamber 106 through the steam passage 105 into the intermediate pressure turbine 103 and is converted into rotational energy by the impeller 101.
[0006]
[Problems to be solved by the invention]
Here, although the above-described shield 130 is widely used, the erosion of the shield 130 by steam has not been regarded as a problem in the past, and the means for solving it has hardly been studied. However, various problems may occur as the development of high-temperature and high-pressure steam turbines progresses in the future. That is, in the conventional steam turbine 100, since the shield 130 is formed by sheet metal welding, the inner peripheral surface near the base 138 of the sleeve portion 132 has an angular shape. For this reason, when the flow velocity of the steam is high, a vortex of steam is generated in the vicinity, and the shield 130 may be eroded and peeled off.
[0007]
Conventionally, since the shield 130 and the dummy 120 have different uses and functions, and have different installation positions and installation processes, it has been common knowledge of those skilled in the art to configure them separately. For this reason, naturally the discontinuous part 121 has arisen between these members. However, if high-temperature and high-pressure steam flows through the flow path wall, erosion may occur at the discontinuous portion 121.
[0008]
Then, this invention is made | formed in view of the above, Comprising: It aims at providing the steam turbine which can suppress the erosion of the shield (heat shielding member) by steam.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a steam turbine according to the present invention (Claim 1) includes a casing that houses a turbine therein, a steam that is formed in the casing, and steam from the outside to the inside of the casing. And a shield that forms a flow path wall of the steam inside the passenger compartment and shields heat transfer from the steam to the passenger compartment, and the shield includes And erosion inhibiting means for inhibiting erosion of the shield by the steam.
[0010]
In the present invention, the shield shields heat transfer from the steam to the passenger compartment and suppresses adverse effects such as creep due to thermal deformation of the passenger compartment. Further, the erosion prevention means suppresses erosion of the shield due to steam. Thereby, peeling of a shield etc. are suppressed and internal leakage of steam is prevented. The construction of the steam flow path wall is not limited to the case where the shield constitutes all of the steam flow path wall, but includes the case where the shield constitutes a part. The channel wall refers to a wall that partitions the steam channel, and includes a wall of a steam chamber, a steam passage of a turbine, and the like.
[0011]
Further, the steam turbine according to the present invention (Claim 2) is the steam turbine according to Claim 1, wherein the shield is extended from the main body portion and a main body portion installed on an inner wall of the vehicle compartment. And a sleeve portion inserted into the nozzle from the inside of the passenger compartment, and the erosion prevention means is configured to substantially follow an inner circumferential surface near the base of the sleeve portion along the flow of the steam. It is formed in a streamline shape.
[0012]
In the present invention, the inner peripheral surface near the base of the sleeve is formed in a substantially streamlined shape, thereby reducing the resistance to steam flow. Thereby, generation | occurrence | production of the vapor | steam vortex in the sleeve base vicinity is suppressed, and the erosion of a shield can be suppressed. The length of the sleeve portion is not particularly limited, and may be a length that allows the inner peripheral surface near the base to be formed into a substantially streamline shape.
[0013]
The steam turbine according to the present invention (Claim 3) is the steam turbine according to Claim 1 or 2, further characterized in that the sleeve portion and the main body portion are integrally formed. Thereby, compared with the formation by the conventional sheet metal welding, the inner peripheral surface near the base of the sleeve portion can be more easily formed into an arbitrary shape.
[0014]
The steam turbine according to the present invention (Claim 4) is the steam turbine according to any one of Claims 1 to 3, wherein the erosion inhibiting means covers the cuff of the sleeve portion from the upstream side. And a fin for guiding the steam to the inside of the cuff by regulating the flow path of the steam. Thereby, the erosion of the cuffs by steam can be suppressed.
[0015]
In addition, the steam turbine according to the present invention (Claim 5) is the steam turbine according to any one of Claims 1 to 4, further comprising the steam flow path wall and in the vehicle interior. It includes a dummy that partitions the turbine and prevents internal leakage of steam, and the shield is integrally formed with the dummy.
[0016]
In the present invention, since the shield is integrally formed with the dummy, it is possible to design and form the vapor flow path wall formed by these integrally. Further, since the shield mooring member and the like can be omitted, there are various benefits such as simplification of the manufacturing process, increased structural strength, and more effective prevention of steam internal leakage. The construction of the steam flow path wall is not limited to the case where the shield constitutes all of the steam flow path wall, but includes the case where the shield constitutes a part. The channel wall refers to a wall that partitions the steam channel, and includes a wall of a steam chamber, a steam passage of a turbine, and the like. In addition to the nozzle chamber integrated dummy, the dummy includes a single dummy, a partition plate, and the like.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiments. In addition, the constituent elements of the embodiments described below include those that can be normally modified by those skilled in the art.
[0018]
FIG. 1 is an overall configuration diagram showing a steam turbine according to an embodiment of the present invention. In the figure, the same components as those in the conventional steam turbine 100 are denoted by the same reference numerals, and the description thereof is omitted. The steam turbine 1 includes an impeller 101, a high-pressure turbine 102, an intermediate-pressure turbine 103, and a casing 110 that accommodates them. A cast dummy 120 that partitions the high-pressure turbine 102 and the intermediate-pressure turbine 103 and is integrally formed with the nozzle chamber 104 of the high-pressure turbine 102 is installed on the outer periphery of the impeller 101. In addition, four high pressure nozzles 113 and four medium pressure nozzles 114 are formed on the outer periphery of the passenger compartment 110 so as to protrude from the outside, and these are inlets 115 and 116 for steam introduced into the passenger compartment 110 from the outside. Configure. The intermediate pressure turbine 103 side inlet portion 115 communicates with the steam chamber 106 formed in the vehicle interior 110, and the steam chamber 106 is separated from the inner wall of the vehicle interior 110 by a gap 134 and the shield portion 2. Is placed. The shield part 2 is a shielding member that shields heat transfer from the steam to the inner wall of the passenger compartment 110 and prevents thermal deformation of the passenger compartment 110.
[0019]
Here, the shield part 2 is integrally formed with the dummy 120 by casting. That is, the steam turbine 1 is characterized in that a shield 120 that is a shielding member is integrally formed with a dummy 120 that also has a nozzle chamber 104 (see FIG. 1). The shield part 2 includes an annular main body part 3, a skirt part 4 that extends from the edge of the main body part 3, and a rear part 5. The skirt 4 has a substantially L-shaped cross section, constitutes a steam flow path wall from the steam chamber 106 to the steam passage 105, and supports one end of the first stage stationary blade 108 at the skirt 7. Note that the other end of the first stage stationary blade 108 is supported by the outer peripheral edge 121 of the dummy 120, thereby fixing the first stage stationary blade 108. Further, the back surface portion 5 extends from the main body portion 3 and is coupled to the outer periphery of the dummy 120. The wall surface 8 on the steam passage 105 side of the back surface portion 5 and the dummy 120 is formed smoothly and continuously, and the flow passage wall of the steam from the steam chamber 106 to the steam passage 105 suppresses resistance to the steam flow. Have a shape to
[0020]
2 is a front cross-sectional view showing the main part of the steam turbine 1 shown in FIG. 1, and FIG. 3 is an enlarged cross-sectional view showing the main part of the steam turbine 1 shown in FIG. The shield part 2 has a sleeve part 6 extending from the main body part 3 and integrally formed by casting. The inner peripheral surface 4 near the base of the sleeve 6 has a smooth streamline shape and suppresses resistance to steam flowing into the steam chamber 106. The sleeve portion 6 is inserted into the intermediate pressure nozzle base 114 and fitted with a cuff 135 against a stepped portion 139 provided on the inner periphery of the intermediate pressure nozzle base 114. An annular seal member 136 is fitted between the outer periphery of the cuff 135 and the inner periphery of the intermediate pressure tube base 114, and the gap 134 is sealed. Thereby, the convection of the vapor | steam in the clearance gap 134 of sleeve part 6 outer periphery, and an internal vapor | steam is suppressed. In addition, the shape of the flow path wall of the steam from the steam chamber 106 to the steam passage 105 and the shape of the inner peripheral surface of the vicinity 138 of the sleeve portion 6 are optimized by three-dimensional fluid analysis so that the fluid loss is small. It is formed.
[0021]
In this embodiment, the steam flows from the inlet portion 115 of the intermediate pressure nozzle 114 through the sleeve portion 6 of the shield portion 2 into the steam chamber 106 of the vehicle compartment 110. At this time, the inner peripheral surface of the vicinity 138 of the sleeve 6 root smoothly guides the steam by its streamline shape, reduces resistance, and suppresses the generation of vortices and separation of the inner peripheral surface. In addition, the continuous flow path wall 8 formed by the main body 3 and the dummy 120 suppresses the generation of steam vortex by the smooth wall surface and suppresses the separation. Note that the stepped portion 139 and the seal member 136 provided in the vicinity of the cuff 135 suppress convection between the inflowing steam and the steam in the gap 134 on the outer periphery of the cuff 135. Further, the steam flows from the steam chamber 106 into the steam passage 105 of the intermediate pressure turbine 103 and is used for the rotational movement of the impeller 101.
[0022]
According to this embodiment, since the sleeve portion 6 and the main body portion 3 are integrally formed by casting, the inner peripheral surface near the base 138 of the sleeve portion 6 is smoother and more easily than in the case of conventional sheet metal welding. Any shape can be formed. As a result, the flow path wall can be designed by three-dimensional fluid analysis, and the resistance of the flow path wall to the steam flow can be reduced to suppress separation and erosion of the wall surface. Moreover, since it formed integrally by casting, compared with the case by the conventional sheet metal welding, an operation | work can be simplified more.
[0023]
In addition, according to this embodiment, since the dummy 120 and the shield part 2 are integrally formed, a mooring member such as the pin 140 which has been conventionally required is not required, and the number of parts can be reduced and complicated manual work is performed. The necessary mooring process can be omitted. Further, since the joint between the dummy 120 and the shield part 2 can be eliminated, the internal leakage of steam can be more reliably prevented as compared with the case of another conventional component. Moreover, the structural strength is also increased. Further, if these are integrally formed by casting, the steam flow path wall 8 can be formed smoothly and in an arbitrary shape, so that the resistance of the flow path wall 8 to the steam flow can be reduced and the peeling and erosion of the wall surface can be suppressed. Furthermore, this integral formation allows the steam flow path wall extending from the cuff 135 through the steam chamber 106 to the steam passage 105 to be designed and formed as a single unit, and therefore has lower resistance and breakage than conventional steam turbines. It is difficult to eat and can be formed into a shape with little loss of fluid energy.
[0024]
Moreover, according to this embodiment, since the shield part 2 shields the heat transfer from the steam to the passenger compartment 110, the thermal deformation of the passenger compartment 110 can be suppressed. Further, the stepped portion 139 and the seal member 136 provided in the vicinity of the cuff 135 suppress convection between the inflowing steam and the air in the gap 134 on the outer periphery of the cuff 135, so that thermal deformation of the vehicle interior 110 can be suppressed.
[0025]
In this embodiment, the inner peripheral surface of the sleeve portion 6 root vicinity 138 has a smooth streamline shape, which is intended to suppress the inner peripheral surface peeling due to the steam flow. Therefore, the streamline shape mentioned here can achieve the above object by reducing the resistance of the steam flow on the inner peripheral surface or suppressing the generation of vortices as compared with the shield 130 by conventional sheet metal welding. It shall mean the shape.
[0026]
Further, in this embodiment, the dummy 120 is a partition member that partitions the high-pressure turbine 102 and the intermediate-pressure turbine 103, but is not limited to the dummy 120 that partitions such a plurality of turbines, and a single turbine is externally provided. A partition may be used. That is, in this embodiment, the purpose of integrally forming the shield part 2 and the dummy 120 is to form a steam channel wall that is not easily eroded, so the dummy 120 constitutes at least a steam channel wall. As long as the turbine is partitioned and internal leakage of steam is prevented.
[0027]
Further, in this embodiment, the flow path wall of the steam is integrally formed from the inside of the intermediate pressure tube stage 114 to the steam passage 105 through the steam chamber 106 by integrally forming the shield portion 2 and the dummy 120. However, it is not necessary to integrally form all the flow path walls of the vapor in this way, and only a portion where the erosion is significant among the flow path walls may be formed into a smooth shape. The reason why the shield part 2 and the dummy 120 are integrally formed is to prevent erosion of the flow path wall due to high-temperature and high-pressure steam.
[0028]
Further, in this embodiment, when the shield part 2 and the dummy 120 are formed by casting, the casing 110 is also generally cast, so that the fitting dimension between the sleeve part 6 cuff 135 and the intermediate pressure tube base 114 cannot be obtained. In some cases, the cuff 135 does not hit the stepped portion 139 of the intermediate pressure tube base 114 (see FIG. 10). Then, a discontinuous portion 141 is generated between the cuff 135 and the intermediate pressure tube base 114, and there may be a problem that the steam is entrained or the steam collides directly with the cuff 135 and the cuff 135 is eroded. In view of this, the fin 9 may be provided at the fitting portion between the cuff 135 and the intermediate pressure tube base 114 so as to cover the cuff 135 from the upstream side of the steam and guide the steam flow into the cuff 135 (see FIG. 4). Thereby, the cuff 135 is protected and erosion is suppressed.
[0029]
【The invention's effect】
As described above, according to the steam turbine according to the present invention (Claim 1), the erosion suppressing means suppresses the erosion of the shield due to the steam. Can be prevented.
[0030]
Further, according to the steam turbine of the present invention (Claim 2), the inner peripheral surface near the base of the sleeve is formed in a substantially streamline shape, so that the resistance to the steam flow can be reduced. Thereby, generation | occurrence | production of the vapor | steam vortex in the sleeve base vicinity is suppressed, and the erosion of a shield can be suppressed.
[0031]
Further, according to the steam turbine of the present invention (Claim 3), since the sleeve portion and the main body portion are integrally formed, the inner peripheral surface near the root of the sleeve portion as compared with the formation by conventional sheet metal welding. Can be more easily formed into an arbitrary shape.
[0032]
According to the steam turbine of the present invention (Claim 4), the fin as the erosion inhibiting means covers the cuff of the sleeve portion from the upstream side to regulate the flow path of the steam, and the steam is supplied to the cuff. Since it leads to the inside of the sleeve, erosion of the cuffs of the sleeve portion can be suppressed.
[0033]
Further, according to the steam turbine of the present invention (Claim 5), since the shield is integrally formed with the dummy, it is possible to design and form the steam flow path wall formed by these as a single body. Further, since parts such as the mooring member of the shield can be omitted, there are various benefits such as simplification of the manufacturing process, increased structural strength, and more effective prevention of steam internal leakage.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram showing a steam turbine according to an embodiment of the present invention.
FIG. 2 is a front sectional view showing a main part of the steam turbine shown in FIG. 1;
FIG. 3 is a side cross-sectional view showing a main part of the steam turbine shown in FIG. 1;
4 is a front cross-sectional view showing a main part of the steam turbine shown in FIG. 1. FIG.
FIG. 5 is an overall configuration diagram showing a conventional steam turbine.
6 is a cross-sectional view of the steam turbine illustrated in FIG.
7 is a side cross-sectional view showing a main part of the steam turbine shown in FIG. 6. FIG.
8 is a cross-sectional view taken along the line BB showing a main part of the steam turbine shown in FIG. 6;
9 is a perspective view showing a main part of the shield shown in FIG. 5. FIG.
10 is a front cross-sectional view showing a main part of the steam turbine shown in FIG.
[Explanation of symbols]
1 Steam turbine 2 Shield part 9 Fin 120 Dummy

Claims (5)

A vehicle housing the turbine inside;
A nozzle that is formed in the passenger compartment and serves as an inlet for steam from the outside to the inside of the passenger compartment,
A shield that shields heat transfer from the steam to the passenger compartment, while configuring the steam passage wall inside the passenger compartment,
And the shield includes
A steam turbine comprising erosion inhibiting means for inhibiting erosion of the shield by the steam. The shield is
A main body installed on the inner wall of the vehicle compartment;
A sleeve portion that extends from the main body portion and is inserted and installed in the nozzle from the inside of the vehicle compartment,
And the erosion inhibiting means includes
The steam turbine according to claim 1, wherein an inner peripheral surface near a base of the sleeve portion is formed in a substantially streamline shape along the flow of the steam. Furthermore, the said sleeve part and the said main-body part were integrally formed, The steam turbine of Claim 1 or 2 characterized by the above-mentioned. The erosion inhibiting means is
The cuff of the cuff is installed so as to cover the cuff from the upstream side, and includes a fin that regulates the flow path of the steam and guides the steam to the inside of the cuff. A steam turbine according to any one of the above. Further, the steam comprises a steam flow path wall, and includes a dummy that partitions the turbine in the passenger compartment to prevent internal leakage of steam, and
The steam turbine according to claim 1, wherein the shield is integrally formed with the dummy.

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