JP2016125439A - Turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a turbine that can demagnetize a rotor blade without opening a cabin and disassembling the rotor blade from a rotor blade row.SOLUTION: The turbine 100 includes: a rotor blade row including multiple rotor blades 1; a stationary body C provided on the outer peripheral side in a radial direction of the turbine 100 relative to the rotor blade row and accommodating the rotor blade row therein; and at least one hole part 6 provided in a position facing the rotor blades 1 of the stationary body C and capable of accommodating a demagnetization device F for demagnetizing the rotor blades 1 therein.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a turbine.

  Of the turbine blades (moving blades), the blades in the stage group (final blade group) located on the downstream side (low pressure side) in the flow direction of the working fluid have a large effect on the output of the turbine. It is important to manage it to work.

  The moving blades of the final blade group have a long blade length, so that the blade has low rigidity, and the vibration displacement tends to increase when excited. In a steam turbine, the flow of the working fluid tends to be disturbed by changes in the degree of vacuum or pressure in the exhaust chamber provided downstream of the working fluid flow direction around the moving blades of the final blade group, and the moving blades are excited. easy. For this reason, the behavior (for example, vibration displacement) of the moving blades of the final blade group during the turbine operation may be measured to evaluate the remaining life of the moving blades or to detect the risk of damage to the moving blades. As a method for measuring the behavior of a moving blade, there is a method in which a sensing object is attached on the cover of the moving blade and a magnetic field change is detected by an electromagnetic sensor arranged in the vicinity of the moving blade (Patent Documents 1 and 2). Etc.).

  By the way, a moving blade may be magnetized between assembly operations. When the moving blade is magnetized, the magnetic field around the moving blade changes, so that the methods of Patent Documents 1 and 2 may not be able to accurately measure the behavior of the moving blade. Therefore, when the moving blade is magnetized, it is necessary to demagnetize or demagnetize the moving blade (hereinafter collectively referred to as demagnetization).

  On the other hand, as a demagnetizing method, for example, there are methods that target videotapes, pipes, turbine rotors after magnetic inspection, and the like (see Patent Documents 3, 4, 5, etc.). However, there is no document that discloses a demagnetization method for moving blades.

US 2008/0206057 JP-A-7-26901 U.S. Pat. No. 4,930,033 Japanese Patent No. 2733909 JP 2013-160647 A

  The demagnetization method for moving blades is generally performed through a moving blade through a portal machine that generates an alternating magnetic field before assembly. However, in a structure where it is not easy to disassemble a moving blade row such as an all-around connected blade structure and take out the moving blade alone, if the moving blade is magnetized after assembling the moving blade row, it is different from the method described above. It is necessary to demagnetize by this method. Even if there is a method of demagnetizing without disassembling the rotor blade row, the demagnetizer cannot be brought close enough to the rotor blades when the casing is closed in the actual plant, and demagnetization is not possible. I can't do it.

  The present invention has been made in view of the above, and an object of the present invention is to provide a turbine capable of demagnetizing a moving blade without opening a casing and without disassembling the moving blade from a moving blade row.

  In order to achieve the above object, a turbine according to the present invention is provided at a position where a moving blade row including a plurality of moving blades, a stationary body that accommodates the moving blade row, and a position of the stationary body facing the moving blades. And at least one hole that can accommodate a demagnetizing device for demagnetizing the moving blade.

  ADVANTAGE OF THE INVENTION According to this invention, the turbine which can demagnetize a moving blade can be provided, without opening a compartment and without disassembling a moving blade from a moving blade row | line | column.

It is the schematic which looked at one structural example of the moving blade row | line | column arrange | positioned at the low pressure | pressure stage of the steam turbine which concerns on 1st Embodiment of this invention from the downstream. FIG. 2 is a schematic diagram illustrating a part of the moving blade row in FIG. 1 in an enlarged manner. It is the schematic showing the moving blade row | line | column of FIG. 1 with the cross section of a stationary body. FIG. 4 is a cross-sectional view taken along arrow IV-IV in FIG. 3. It is arrow sectional drawing by the arrow VV line of FIG. It is the schematic which looked at a part of moving blade row | line | column of the steam turbine which concerns on 2nd Embodiment of this invention along the circumferential direction of the turbine rotor with the cross section of a stationary body. It is a figure which illustrates the alternating current sent through a demagnetizing device. It is the figure which illustrated the response waveform (demagnetization response waveform) of the rotor cascade in a demagnetized state. It is the figure which illustrated the response waveform (magnetization response waveform) of the rotor cascade in a magnetized state. It is the figure which illustrated the response waveform (electromagnetic excitation response waveform) of the rotor cascade in an electromagnetic excitation state.

<First Embodiment>
(Constitution)
The steam turbine according to the present embodiment includes a plurality of blade stages having a moving blade row and a stationary blade row in a stationary body. The working fluid flowing through the working fluid flow path of the steam turbine is rectified by the stationary blade row, and rotates the turbine rotor that fixes the moving blade row.

  FIG. 1 is a schematic view of a configuration example of a moving blade row arranged in a low pressure stage of a steam turbine according to the present embodiment as viewed from the downstream side, and FIG. 2 is an enlarged view of a portion of the moving blade row of FIG. FIG. Hereinafter, a configuration in which the present invention is applied to a moving blade row arranged in a low-pressure stage of a steam turbine will be described, but a configuration in which the present invention is applied to a moving blade row arranged in another paragraph is basically the same. .

  As shown in FIGS. 1 and 2, the moving blade 1 includes a profile portion 3 and a cover portion 4. A plurality of moving blades 1 are provided on the outer peripheral portion of the disk 2 along the circumferential direction of the turbine rotor to constitute a moving blade row. The cover part 4 is provided on the outer peripheral part of each profile part 3 in the blade length direction. In FIG. 1, the moving blade 1 rotates clockwise (in the direction of arrow Y in FIG. 1) when viewed from the downstream side by the working fluid flowing through the working fluid flow path. However, the direction of rotation does not affect the present invention. A stationary blade row (not shown) having a plurality of stationary blades is provided upstream of the moving blade 1 of the turbine rotor in the flow direction of the working fluid.

  The moving blade 1 is assembled by pre-twisting the profile portion 3 to apply a pressing force to the cover portion 4 between adjacent blades, or by the centrifugal force when the moving blade 1 rotates. A structure in which a plurality of moving blades 1 are connected by a method of applying a pressing force to the contact surface 5 of the cover portion 4 between adjacent blades by twisting back generated in the blades (all-around connected blade structure). FIG. 2 illustrates the former connection structure.

  FIG. 3 is a schematic view showing the blade row of FIG. 1 together with a cross section of a stationary body. 3, parts that are the same as in FIG. 1 are given the same reference numerals, and descriptions thereof will be omitted as appropriate.

  As shown in FIG. 3, the steam turbine 100 according to the present embodiment includes a moving blade 1 and a stationary body C. The stationary body C is provided on the outer peripheral side in the radial direction of the steam turbine 100 with respect to the moving blade 1 and is configured to accommodate the moving blade 1 and the stationary blade. The stationary body C is, for example, a passenger compartment (casing), but when there is another member (for example, a diaphragm) provided on the outer peripheral side of the moving blade 1, it is also included in the stationary body C.

  The stationary body C is provided with a hole 6 capable of accommodating a demagnetizing device F (described later) and a hole 7 capable of accommodating a sensor S (described later). The hole 6 and the hole 7 are formed according to the shapes of the demagnetizer F and the sensor S, respectively, and the sizes and shapes of the holes 6 and 7 may be different or the same. Hereinafter, the hole 6 and the hole 7 will be described.

  4 is a cross-sectional view taken along line IV-IV in FIG.

  As shown in FIG. 4, in the present embodiment, the stationary body C is provided with an outer peripheral side hole 6 </ b> A and an upstream side hole 6 </ b> B as the holes 6.

  The outer peripheral side hole 6A faces the stationary body C so as to face the outer end in the radial direction of the steam turbine 100 (in the direction of arrow Z in FIG. 4) with respect to the tip of the rotor blade 1 (the cover 4 in this example). Is provided. A plurality of outer peripheral side holes 6A are provided in the stationary body C along the circumferential direction of the turbine rotor (see FIG. 3).

  The upstream hole 6B is stationary so as to face the upstream side in the axial direction of the steam turbine 100 (the direction opposite to the arrow X in FIG. 4) with respect to the tip of the rotor blade 1 (the cover 4 in this example). The body C is provided. Although not particularly illustrated, a plurality of upstream holes 6B are also provided in the stationary body C along the circumferential direction of the turbine rotor, as with the outer holes 6A. FIG. 4 illustrates the case where the upstream side hole 6B is provided at a position corresponding to the outer peripheral side hole 6A of the stationary body C in the circumferential direction of the turbine rotor. It may be provided at a shifted position. Moreover, if an appropriate effect is acquired, it is good also as installation only of the outer peripheral side hole 6A or only the upstream hole 6B.

  In the configuration example of FIG. 4, the demagnetizer F is accommodated in each of the outer peripheral side hole 6A and the upstream side hole 6B. The demagnetizer F is configured to generate an alternating magnetic field by energization, for example. When the moving blade 1 rotates in the arrow Y direction (see FIG. 3), it passes through the position (demagnetization position) facing the demagnetizer F and is demagnetized. In order to demagnetize the rotor blade 1, the rotor blade 1 needs to pass through the demagnetization position at least once. In the case of demagnetizing all the moving blades 1 in the moving blade row, for example, it is preferable to manually rotate the moving blade 1 one or more times by a driving device (not shown).

  FIG. 5 is a cross-sectional view taken along line VV in FIG.

  As shown in FIG. 5, in the present embodiment, the stationary body C is provided with an outer peripheral side hole 7 </ b> A and an upstream side hole 7 </ b> B as the holes 7.

  7 A of outer peripheral side holes are provided in the stationary body C so that it may oppose the front-end | tip part (cover part 4 in this example) of the moving blade 1 to the radial direction (arrow Z direction of FIG. 5) of the steam turbine 100. ing.

  The upstream hole portion 7B is stationary so as to face the upstream side in the axial direction of the steam turbine 100 (the direction opposite to the arrow X in FIG. 5) with respect to the tip side of the rotor blade 1 (in this example, the cover portion 4). The body C is provided. Although not shown in particular, the upstream side hole 7B is also displaced in the rotational direction of the moving blade 1 with respect to the outer side hole 6B, and the stationary body C is moved in the circumferential direction of the turbine rotor. A plurality are provided along. FIG. 5 illustrates the case where the upstream side hole 7B is provided at a position corresponding to the outer peripheral side hole 7A of the stationary body C in the circumferential direction of the turbine rotor. It may be provided at a shifted position.

  As shown in FIG. 5, the sensor S is accommodated in each of the outer peripheral side hole 7A and the upstream side hole 7B. The sensor S is for measuring the behavior of the moving blade 1 during operation of the steam turbine. 5 illustrates the case where the sensor S is accommodated in the outer peripheral hole 7A and the upstream hole 7B. However, if the behavior of the moving blade 1 can be measured, the outer peripheral hole 7A and the upstream hole 7B What is necessary is just to accommodate the sensor S in one side.

(effect)
(1) In this embodiment, since the hole 6 capable of accommodating the demagnetizing device F for demagnetizing the moving blade 1 is provided at a position facing the moving blade 1 of the stationary body C, the hole 6 is removed. By accommodating the magnetic device F and rotating the moving blade 1, the moving blade 1 can be demagnetized. Therefore, the moving blade can be demagnetized without opening the stationary body and without disassembling the moving blade row.

  (2) In the case of the above-described method in which the pressing force is applied to the cover portion 4 between adjacent blades by assembling the profile portion 3 in a previously twisted state, the cover portions 4 of the adjacent blades 1 The contact surface 5 always comes into contact immediately after the start of the connection of 1 (see FIG. 2). In the case of the above-described method in which the pressing force is applied to the cover portion 4 between adjacent blades by the twisting return generated in the profile portion 3 due to the centrifugal force when the moving blade 1 rotates, the moving blade 1 is stationary. Although a gap is formed between the cover portions 4 of the adjacent rotor blades 1, it has a very small size. There is no space for installing the demagnetizing device F between the cover portions 4, and it is not preferable to install the demagnetizing device F on the rotating body side in consideration of attachment, removal, wiring, and the like. Therefore, in order to demagnetize the moving blades of the moving blade row having the all-round connection blade structure with the casing closed, there is no other way than providing a demagnetizing device on the outer peripheral side of the moving blade row. However, in general, it is difficult to secure a space for providing a demagnetizing device around the rotor blade row of the turbine.

  In contrast, in the present embodiment, since the hole 6 capable of accommodating the demagnetizing device F is provided in the stationary body C, it is not necessary to secure a space for providing the demagnetizing device F around the rotor blade 1. .

  (3) In this embodiment, the stationary body C is provided with the outer peripheral side hole 6A and the upstream side hole 6B. Therefore, when the rotor blade 1 is demagnetized, the demagnetizing device F is accommodated in the outer peripheral side hole 6A and the upstream side hole 6B, so that demagnetization can be performed from the outer peripheral side and the upstream side of the rotor blade 1. Therefore, the demagnetization effect of the moving blade 1 can be improved.

  (4) The steam turbine 100 according to the present embodiment can be easily obtained by simply providing the hole 6 in the stationary body C and performing a simple operation on the stationary body of the steam turbine.

Second Embodiment
(Constitution)
FIG. 6 is a schematic view of a part of the moving blade row of the steam turbine according to the present embodiment as viewed along the circumferential direction of the turbine rotor together with the cross section of the stationary body. In FIG. 6, parts that are the same as those of the steam turbine 100 of the first embodiment are given the same reference numerals, and descriptions thereof are omitted as appropriate.

  The steam turbine 100 according to the present embodiment is different from the steam turbine 100 of the first embodiment in that a dummy D is accommodated in the outer peripheral side hole 6A instead of the demagnetizing device F, and a control device 8 is further provided. Other configurations are the same as those of the first embodiment.

  The dummy D is for blocking the communication between the inside of the outer peripheral side hole 6A and the working fluid flow path, and suppressing the inflow of the working fluid from the working fluid flow path to the outer peripheral side hole 6A. 6 illustrates the case where the dummy D is formed so as to fill the inside of the outer peripheral side hole 6A. However, the shape of the dummy D is not limited as long as the above-described function can be exhibited. Further, in FIG. 6, the dummy D is accommodated in the outer peripheral side hole 6A, but the dummy D may be accommodated in the upstream side hole 6B.

  The control device 8 is connected to the demagnetizing device F and has a function of controlling the magnitude (frequency) of the alternating current flowing through the demagnetizing device F. Generally, the magnitude of the alternating magnetic field generated by the demagnetizing device is correlated with the magnitude of the alternating current flowing through the demagnetizing device. Therefore, the control device 8 controls the magnitude of the alternating magnetic field generated by the demagnetizing device F by controlling the magnitude of the alternating current flowing through the demagnetizing device F. The magnitude of the alternating current that flows through the demagnetizing device F may be a value that allows the AC magnetic field generated by the demagnetizing device F to flow through the demagnetizing device F to demagnetize the rotor blade 1.

  FIG. 7 is a diagram illustrating an alternating current that flows through the demagnetizer F. FIG. The vertical axis represents the amplitude A of the alternating current, and the horizontal axis represents the elapsed time t from when the alternating current began to flow through the demagnetizer F.

  In the example of FIG. 7, the control device 8 gradually increases the amplitude from zero (first step), maintains the set value A1 for the set time t1 (second step), and gradually decreases from the set value A1. Then, the magnitude of the alternating current is controlled so that it becomes zero (third step). The set time t1 described above is a time during which an AC magnetic field for demagnetization can sufficiently act on all the rotor blades 1 in the rotor blade row. 7 illustrates the first to third steps. However, if the moving blade 1 can be demagnetized while maintaining the amplitude at a desired value for a certain period of time, the amplitude increases in the first step. However, the method of decreasing the amplitude in the third step is not limited.

  When the alternating current illustrated in FIG. 7 is passed through the demagnetizing device F, the demagnetizing device F gradually increases the magnitude of the alternating magnetic field from zero to an arbitrary value (first value) equal to or greater than the threshold. Is maintained for the time t1, and then an alternating magnetic field is generated that gradually decreases from the first value to zero. The first value described above is the magnitude of the alternating magnetic field corresponding to the alternating current when the amplitude reaches the set value A1 in FIG.

  As shown in FIG. 6, the control device 8 includes a switch 9 and a comparison device 10.

  The switch 9 has a function of turning on and off the demagnetizer F. 6 illustrates the case where the control device 8 includes the switch 9, but the switch 9 may be provided separately from the control device 8 as long as the above-described function can be exhibited.

  The comparison device 10 is electrically connected to the sensor S, and needs to be demagnetized by measuring the response waveform of the moving blade 1 measured by the sensor S in advance and storing it in the storage device of the control device 8, for example. Compared with the response waveform (reference response waveform) of the moving blade 1 having no air gap, for example, it has a function of determining the degree of magnetization, electromagnetic excitation, etc. of the moving blade 1 based on the difference from the reference response waveform. 6 illustrates a configuration in which the control device 8 includes the comparison device 10, but the comparison device 10 may be provided separately from the control device 8 as long as the above-described functions can be exhibited. Further, instead of providing the comparison device 10, for example, the response waveform of the moving blade 1 obtained by the sensor S and the reference response waveform are displayed on an output device such as a display device or a printing device, and the operator compares the two. The degree of magnetization of the moving blade 1 and the degree of electromagnetic excitation may be determined.

  The operation of the comparison device 10 will be described.

  FIG. 8 is a diagram illustrating a response waveform (demagnetization response waveform) of the rotor blade 1 in a demagnetized state. The vertical axis indicates the magnetic field (the strength of the magnetic field), and the horizontal axis indicates the elapsed time after the rotation of the rotor blade 1 is started.

  Each period of the demagnetization response waveform shown in FIG. 8 corresponds to each rotor blade 1 in the rotor blade row. In each period of the demagnetization response waveform, the strength of the magnetic field increases as the moving blade 1 approaches the position (detection position) where the moving blade 1 faces the sensor S, and becomes maximum when the moving blade 1 reaches the detection position. It decreases as the wing 1 moves away from the detection position.

  As shown in FIG. 8, in each period of the demagnetization response waveform, there is a point (passing point P) where the strength of the magnetic field crosses the threshold value TG from the bottom to the top. The sensor S can accurately measure the behavior of the moving blade 1 corresponding to the period when the strength of the magnetic field exceeds the threshold value TG (that is, the passing point P exists). On the other hand, when the strength of the magnetic field does not cross the threshold value TG (that is, there is no passing point P), the sensor S cannot accurately measure the behavior of the moving blade 1 corresponding to the cycle.

  The demagnetization response waveform shown in FIG. 8 has the same shape as the reference response waveform. Therefore, the comparison device 10 compares the demagnetization response waveform with the reference response waveform and determines that the rotor blade 1 is in a demagnetized state.

  FIG. 9 is a diagram illustrating a response waveform (magnetization response waveform) of the rotor blade 1 in a magnetized state. The vertical axis indicates the magnetic field (the strength of the magnetic field), and the horizontal axis indicates the elapsed time after the rotation of the rotor blade 1 is started.

  As shown in FIG. 9, the magnetization response waveform is different from the demagnetization response waveform (see FIG. 8), and disturbance occurs in the period corresponding to the magnetized blade 1. That is, the magnetic field strength does not straddle the threshold value TG in the period corresponding to the magnetized moving blade 1 (the passing point P does not exist). In this case, the comparison device 10 compares the magnetization response waveform with the reference response waveform, determines that the rotor blade 1 is in a magnetized state, and determines the degree of magnetization. In the magnetization response waveform shown in FIG. 9, there is no passing point P in the period corresponding to the magnetized moving blade 1. Therefore, the sensor S cannot accurately measure the behavior of the moving blade 1 corresponding to the cycle in which the passing point P does not exist.

  After the degree of magnetization of the moving blade 1 is determined by the comparison device 10, the control device 8 sends an alternating current to the demagnetizing device F based on the determination result of the comparison device 10, and the degree of magnetization of the moving blade 1. An alternating magnetic field corresponding to is generated to demagnetize the rotor blade 1. Note that the control device 8 may cause a DC magnetic field to flow through the demagnetizer F before flowing an AC current through the demagnetizer F to generate a DC magnetic field and raise or lower the magnetization response waveform as necessary. Thereafter, the moving blade 1 is demagnetized by the same method as described above.

  FIG. 10 is a diagram illustrating a response waveform (electromagnetic excitation response waveform) of the moving blade 1 in the electromagnetic excitation state. The vertical axis indicates the magnetic field (the strength of the magnetic field), and the horizontal axis indicates the elapsed time after the rotation of the rotor blade 1 is started. Electromagnetic excitation means that the moving blade 1 is forcibly excited by a DC magnet or an AC magnet, and is performed when the vibration characteristics of the moving blade 1 in the state of forced excitation are acquired. As shown in FIG. 10, the electromagnetic excitation response waveform has a stronger magnetic field (that is, the response waveform has a larger amplitude) than the demagnetization response waveform (see FIG. 8). In this case, the comparison device 10 compares the electromagnetic excitation response waveform with the reference response waveform, determines that the moving blade 1 is in the electromagnetic excitation state, and determines the degree of electromagnetic excitation.

(effect)
Also in this embodiment, since the hole 6 capable of accommodating the demagnetizing device F for demagnetizing the moving blade 1 is provided at the position facing the moving blade 1 of the stationary body C, the same effect as the first embodiment is provided. Is obtained. In addition, the following effects can be obtained in the present embodiment.

  The steam turbine 100 according to the present embodiment includes a switch 9 that turns on and off the demagnetizer F. Therefore, malfunction of the demagnetizer F with respect to the moving blade 1 can be suppressed, and the safety of the steam turbine 100 can be improved.

  Further, the steam turbine 100 according to the present embodiment compares the response waveform of the moving blade 1 measured by the sensor S with the reference response waveform, and determines the degree of magnetization, electromagnetic excitation, etc. of the moving blade 1. 10 is provided. Therefore, it is possible to easily determine the degree of magnetization of the moving blade 1 without separately providing a device for measuring the residual magnetic field of the moving blade 1.

  In addition, the steam turbine 100 according to the present embodiment includes a dummy D that blocks communication between the inside of the hole 6 and the working fluid channel and suppresses inflow of the working fluid from the working fluid channel to the hole 6. ing. Therefore, by accommodating the dummy D in the hole 6 that does not accommodate the demagnetizer F among the plurality of holes 6, the working fluid flows into the hole 6 during the operation of the steam turbine 100 and leakage loss or the like occurs. This can be suppressed. Further, when the demagnetizer F is extracted from the hole 6 in consideration of the thermal influence during the operation of the steam turbine 100, the working fluid is transferred to the hole 6 by accommodating the dummy D in the hole 6. It is possible to suppress the occurrence of leakage loss due to inflow.

<Others>
The present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described. For example, a part of the configuration of each embodiment can be deleted.

  In each of the above-described embodiments, the case where a plurality of the holes 6 and the holes 7 are provided in the stationary body C is illustrated. However, as long as the moving blade 1 can be demagnetized and the behavior of the moving blade 1 can be measured. The hole 6 and the hole 7 may be provided in the stationary body C at least one.

  Further, in each of the above-described embodiments, the case where the hole 6 and the hole 7 are provided on the outer peripheral side and the upstream side of the moving blade 1 is illustrated. However, the moving blade 1 is demagnetized and the behavior of the moving blade 1 is measured. As long as it is possible, the hole 6 and the hole 7 may be provided on the downstream side of the rotor blade 1.

  Further, in each of the above-described embodiments, the case where the present invention is applied to a moving blade row having an all-around linked blade structure has been described. However, for example, a gas turbine and a moving blade having a structure in which the blade tip is not connected are described. The present invention can also be applied to blade cascades, operation in test facilities, and rotating bodies such as engines.

DESCRIPTION OF SYMBOLS 1 Rotating blade 2 Disc 3 Profile part 4 Cover part 5 Contact surface 6 (6A, 6B) Hole part 7 (7A, 7B) Hole part 8 Control apparatus 9 Switch 10 Judgment apparatus 100 Steam turbine C Stationary body F Demagnetizing apparatus S Sensor D dummy X axis direction Y rotation direction Z radial direction A, A1 amplitude t, t1 time P passing point TG threshold

Claims (11)

A moving blade row comprising a plurality of moving blades;
A stationary body for housing the blade row;
A turbine comprising: at least one hole provided in a position of the stationary body facing the moving blade and capable of accommodating a demagnetizing device for demagnetizing the moving blade. The turbine according to claim 1,
The turbine further comprising the demagnetizing device accommodated in the hole. The turbine according to claim 2,
A turbine comprising: at least one sensor for measuring a behavior of the moving blade at a position shifted in a rotation direction of the moving blade row with respect to the hole of the stationary body. The turbine according to claim 3.
The turbine is characterized in that the sensor is an electromagnetic sensor. The turbine according to claim 2,
The turbine according to claim 1, wherein the demagnetizer generates an alternating magnetic field. The turbine according to claim 5, wherein
A control device connected to the demagnetizer;
The control device gradually increases the alternating magnetic field from zero to a first value that is equal to or greater than a threshold, maintains the first value, and then gradually decreases from the first value to zero. The turbine is characterized by controlling the demagnetizing device so that The turbine according to claim 2,
A turbine comprising a switch connected to the demagnetizing device and for switching the demagnetizing device on and off. The turbine according to claim 3.
A turbine comprising: a determination device connected to the sensor and determining a degree of magnetization or electromagnetic excitation of the moving blade based on a response waveform acquired by the sensor. The turbine according to claim 1,
A turbine comprising a dummy housed in the hole. The turbine according to claim 1,
The turbine is characterized in that the moving blade row is a moving blade row arranged in a low pressure stage of the turbine. In a turbine remodeling method comprising a moving blade row including a plurality of moving blades, and a stationary body that accommodates the moving blade row,
A turbine remodeling method comprising: providing at least one hole capable of accommodating a demagnetizing device for demagnetizing the moving blade at a position of the stationary body facing the moving blade.

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