JP2015001414A - Tip clearance measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a measurement error of tip clearance without involving influence of an environmental temperature and restriction on measurement objects.SOLUTION: There is provided a tip clearance measurement device for measuring a tip clearance D in an axial flow rotary machine 1. The tip clearance measurement device includes: a first laser sensor 50 which emits a laser beam 51 in a prescribed direction; a second laser sensor 60 which emits a laser beam 61 in a prescribed direction other than the above prescribed direction; a tachometer 70 capable of detecting a rotational frequency of a rotor blade 30; and a data processing unit 80 which calculates a passage time Tfrom a prescribed position to another prescribed position of the rotor blade 30 in accordance with detection results of the first laser sensor 50 and the second laser sensor 60 and calculates a rotation time Tfor a prescribed phase of the rotor blade 30, which is detected by the tachometer 70, and calculates the tip clearance D by a tip clearance correction formula comprising the passage time T, the rotation time T, and corrected tip clearance values a and b.

Description

  The present invention relates to a tip clearance measuring device that measures a gap distance (tip clearance) between a moving blade and a casing in an axial-flow rotating machine.

  In an axial-flow rotating machine such as a gas turbine or a steam turbine, a rotor shaft having a plurality of moving blades in a circumferential direction is rotatably installed in a cylindrical casing, and the rotor shaft and the moving blade are rotated in the casing. Is. In order to improve operational safety and operational efficiency as an axial-flow rotating machine, an appropriate tip clearance gap is provided between the moving blade and the casing.

  When the tip clearance is too small, when the axial flow rotating machine is operated and the rotor shaft and the moving blade are rotated, the moving blade is deformed by centrifugal force or thermal expansion, so that the moving blade and the casing are There is a risk that the safety of the axial-flow rotating machine is impaired due to interference. On the other hand, when the tip clearance is excessive, when the axial flow rotating machine is operated and the rotor shaft and the rotor blade are rotated, the fluid flows out from the gap between the rotor blade and the casing in the axial direction. There is a risk that the fluid does not contribute to the rotating operation of the rotor blade, and the operating efficiency of the axial-flow rotating machine is reduced.

  Therefore, in order to ensure safety and operating efficiency as an axial flow rotating machine, it is necessary to minimize the tip clearance to such an extent that the moving blade and the casing do not interfere with each other. Therefore, the axial flow rotating machine is provided with a chip clearance measuring device in order to confirm whether the designed chip clearance is secured. Various methods are known for measuring the tip clearance, such as an overcurrent method, a capacitance method, a light amount method, and a discharge method.

Japanese Patent Laid-Open No. 9-324603

  However, these chip clearance measuring methods have the following problems. In the chip clearance measurement method using the eddy current method and the electrostatic capacitance method, the electrical resistance changes as the environmental temperature changes, so the measurement result is greatly influenced by the environmental temperature at the time of measurement, and the chip that is the measurement result The clearance cannot be measured accurately. In the light amount type chip clearance measurement method, since the distance is measured by the intensity of light reflection, the sensitivity changes due to dirt on the measurement surface and the light emitting / receiving surface of the sensor, and the chip clearance cannot be measured accurately. In the discharge type tip clearance measuring method, since the clearance value cannot be obtained as continuous data, it is unsuitable for measuring the tip clearance in an axial rotating machine. In the eddy current type, electrostatic capacitance type and discharge type chip clearance measurement methods, the material of the object to be measured is limited to a conductor.

  As another tip clearance measuring method, there is, for example, Patent Document 1. This is because the outgoing light emitted at an angle θ receives the light scattered and reflected by the moving blade, detects the time when the moving blade passes one arbitrary point, and the time when the moving blade passes two different points by the position sensor. The tip clearance is geometrically measured from the rotational speed of the moving blade.

  However, an error occurs in the angle θ, which is a known emission direction of the emitted light, due to an attachment error of the emission part, and an accurate chip clearance cannot be calculated.

  The present invention has been made in view of the above problems, and an object of the present invention is to reduce the measurement error of the tip clearance without the influence of the environmental temperature and the limitation of the object to be measured.

  A tip clearance measuring device according to a first invention for solving the above-mentioned problems includes a cylindrical casing, a rotor shaft that is rotatably supported in the casing, and an outer periphery of the rotor shaft that is implanted in the casing together with the rotor shaft. A tip clearance measuring device that measures a tip clearance that is a distance between a blade top portion of the moving blade and an inner peripheral surface of the casing in an axial-flow rotating machine including a rotating blade, and is installed in the casing. A first laser sensor capable of detecting that the moving blade has passed a predetermined position by emitting a laser beam in a predetermined direction and receiving reflected light reflected by the moving blade, and installed in the casing, By receiving the reflected light reflected from the moving blade by emitting laser light in a predetermined direction different from the predetermined direction, the moving blade is different from the predetermined position. From the detection results of the second laser sensor capable of detecting passing through a fixed position, the tachometer capable of detecting the rotational speed of the moving blade or the rotor shaft, and the detection results of the first laser sensor and the second laser sensor, Calculating the passage time of the moving blade from the predetermined position to the other predetermined position, calculating the rotation time of the moving blade for a predetermined phase detected by the tachometer, and calculating the passage time and the rotation time; A data processing unit for calculating a tip clearance by a tip clearance calibration formula comprising a tip clearance calibration value, and the tip clearance calibration value is obtained by assembling a simulated moving blade different from the moving blade in the casing. It is characterized by being.

  A chip clearance measuring apparatus according to a second invention for solving the above-mentioned problems is the chip clearance measuring apparatus according to the first invention, wherein the first laser sensor and the second laser sensor are connected to the first laser light and the first laser light. The two laser beams are inclined with respect to each other in a direction perpendicular to the axial direction of the casing, and the intersection of the first laser beam and the second laser beam is located inside the blade top of the moving blade. It is installed so that it may become the circumference side.

  A chip clearance measuring device according to a third invention for solving the above-mentioned problems is the chip clearance measuring device according to the first invention, wherein the first laser sensor and the second laser sensor are connected to the first laser beam and the first laser beam. The two laser beams are installed so as to be inclined with respect to each other so as to spread toward the inner peripheral side of the casing so that they do not intersect in a direction perpendicular to the axial direction of the casing.

  A chip clearance measuring apparatus according to a fourth invention for solving the above-mentioned problems is the chip clearance measuring apparatus according to any one of the first to third inventions, wherein the first laser sensor and the second laser sensor are It installs toward the rotation direction side of the said moving blade rather than the center of a casing.

  According to the chip clearance measuring apparatus according to the first aspect of the present invention, the moving blade is not limited as long as it reflects the first laser beam and the second laser beam. It is not affected. Further, the tip clearance calibration values a and b are obtained by using the simulated rotor shaft 120 different from the rotor shaft 20 and the moving blade 30, the first simulated moving blade 130A and the second simulated moving blade 130B, and the first laser sensor 50 and Since the calculation is performed in the casing 10 in which the second laser sensor 60 is already installed, mounting errors of the first laser sensor 50 and the second laser sensor 60 do not affect the calculated value of the chip clearance D. That is, an installation error or the like of the first laser sensor 50 and the second laser sensor 60 can be allowed. Therefore, more accurate tip clearance D can be measured.

  According to the chip clearance measuring apparatus according to the second invention, the first laser beam and the second laser beam are emitted to a small range, and therefore the moving blade that is the measurement target among the plurality of moving blades installed on the rotor shaft Can be easily identified and the risk of misidentification can be reduced.

  According to the chip clearance measuring apparatus of the third invention, the first laser beam and the second laser beam do not intersect with each other, so there is no need to consider the position of the intersection between the first laser beam and the second laser beam. The restriction on the installation angle of the one laser sensor and the second laser sensor can be relaxed.

  According to the chip clearance measuring apparatus according to the fourth aspect of the invention, even when the amount of reflected light changes due to dirt on the measurement surface of the moving blade, the time in the detection result of the first laser sensor and the second laser sensor does not change. Measurement errors can be reduced.

It is explanatory drawing which shows a part of axial flow rotary machine provided with the chip clearance measuring apparatus which concerns on Example 1. FIG. It is a graph which shows the relationship of the reflected light quantity v with respect to time t obtained by the 1st laser sensor of an axial flow rotary machine in Example 1, and the 2nd laser sensor. FIG. 3 is an enlarged view of the vicinity of the top of the rotor blade of the axial flow rotating machine according to the first embodiment. FIG. 3 is an enlarged view of the vicinity of the top of the first simulated moving blade and the second simulated moving blade of the axial-flow rotating machine in the first embodiment. It is explanatory drawing which shows a part of axial flow rotary machine provided with the chip clearance measuring device which concerns on Example 2. FIG. It is a graph which shows the relationship of the reflected light quantity v with respect to time t obtained by the 1st laser sensor of an axial flow rotary machine in Example 2, and the 2nd laser sensor. It is explanatory drawing which shows a part of axial flow rotary machine provided with the chip clearance measuring device which concerns on Example 3. FIG. It is a graph which shows the relationship of the reflected light quantity v with respect to the time t obtained by the 1st laser sensor of an axial flow rotary machine in Example 3, and a 2nd laser sensor.

  Embodiments of a chip clearance sensor device according to the present invention will be described below in detail with reference to the accompanying drawings. Needless to say, the present invention is not limited to the following examples, and various modifications can be made without departing from the spirit of the present invention.

  First, the structure of an axial-flow rotating machine provided with a tip clearance measuring device according to Embodiment 1 of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, an axial-flow rotating machine 1 equipped with a tip clearance measuring device according to this embodiment includes a cylindrical casing 10, a rotor shaft 20 that is rotatably supported in the casing 10, and a rotor shaft. And a rotor blade 30 which is provided on the outer periphery of the rotor 20 and is rotated in the casing 10 together with the rotor shaft 20. In the axial-flow rotating machine 1 according to the present embodiment, a gap 40 is provided between the blade top (tip) 31 of the moving blade 30 and the inner peripheral surface 11 of the casing 10 in order to prevent interference between the moving blade 30 and the casing 10. And the gap 40 is set to a predetermined distance (chip clearance) D.

  When the tip clearance D is too small, when the axial rotating machine 1 is operated and the rotor shaft 20 and the moving blade 30 are rotated, the moving blade 30 is deformed by centrifugal force or thermal expansion. The moving blade 30 and the casing 10 may interfere with each other, and the safety of the axial-flow rotating machine 1 may be impaired. On the other hand, when the tip clearance D is excessive, when the axial-flow rotating machine 1 is operated and the rotor shaft 20 and the rotor blade 30 are rotated, fluid (not shown) is caused between the rotor blade 30 and the casing 10. By flowing out from the gap 40 in the axial direction (the front-rear direction in FIG. 1), the fluid does not contribute to the rotating operation of the moving blade 30 and the operating efficiency of the axial-flow rotating machine 1 may be reduced.

  Therefore, in this embodiment, in order to ensure the safety and operating efficiency of the axial-flow rotating machine 1, the axial-flow rotating machine 1 is provided with a tip clearance D measuring device. Thereby, the tip clearance D can be accurately measured, and it can be confirmed that the tip clearance D is the minimum setting that ensures safety and operating efficiency.

  The axial-flow rotating machine 1 in the present embodiment is a measuring device for accurately measuring the tip clearance D, a first laser sensor 50 for detecting that the rotating moving blade 30 has passed a predetermined position, A second laser sensor 60 for detecting that the rotating blade 30 that has been rotated has passed a predetermined position different from the predetermined position, and a tachometer for detecting the rotation speed of the rotor blade 30, that is, the rotation speed of the rotor shaft 20. 70, a first laser sensor 50, a second laser sensor 60, and a data processing unit 80 for calculating the chip clearance D from the detection results of the tachometer 70.

  The first laser sensor 50 and the second laser sensor 60 are respectively provided with an emission unit (not shown) for emitting the first laser beam 51 and the second laser beam 61, and the emitted first laser beam 51 and the second laser beam 61 are moved. And a light receiving unit (not shown) that senses light reflected by the blade 30 (reflected light), and the rotating blade 30 is rotated so that the first laser beam 51 and the second laser beam 61 are traversed. The emitting part is installed toward the inner peripheral side of the casing 10 so as to emit the laser light 51 and the second laser light 61 toward the rotational trajectory range of the rotor blade 30, that is, toward the inner peripheral side of the casing 10 (lower side in FIG. 1). Is done.

  In the present embodiment, the first laser sensor 50 emits the first laser beam 51 from the casing 10 side toward the rotational direction side (right side in FIG. 1) of the rotor blade 30 from the center of the rotor shaft 20. As described above, the second laser sensor 60 is installed so as to be inclined with respect to the radial direction of the casing 10. 1 is disposed so as to be inclined toward the radial direction of the casing 10.

  That is, the first laser sensor 50 and the second laser sensor 60 are configured so that the first laser beam 51 and the second laser beam 61 are moved from the installation position of the first laser sensor 50 and the second laser sensor 60 to the casing 10 and the rotor shaft 20. It is installed in the casing 10 so as to intersect between the center positions. As shown in FIG. 3, the first laser sensor 50 is arranged such that the intersection point P between the first laser beam 51 and the second laser beam 61 is located on the inner peripheral side of the trajectory 31 a of the blade top 31 of the moving blade 30. The installation angle of the second laser sensor 60 is set.

Further, the first laser beam 51 and the second laser beam 61 are arranged such that the intersection point P of the first laser beam 51 and the second laser beam 61 is not in the vicinity of the center of the rotor shaft 20 and the blade root portion of the rotor blade 30 but in the vicinity of the blade top portion 31 of the rotor blade 30. It is preferable to set the installation angle of the sensor 50 and the second laser sensor 60. According to this, the influence on the calculated value of the tip clearance D due to the measurement error of the passage time T _X of the moving blade 30 described later can be suppressed.

  Details of the measurement of the tip clearance D in the above-described axial-flow rotating machine 1 will be described below.

  When the rotating blade 30 to be rotated traverses the path of the first laser beam 51 and the path of the second laser beam 61, the amount of reflected light (reflected light) with respect to time t obtained by the first laser sensor 50 and the second laser sensor 60 is reflected. (Amount of light) v is shown in FIGS. 2A and 2B, respectively. The amount of reflected light v detected by a light receiving unit (not shown) of the first laser sensor 50 and the second laser sensor 60 is the first laser beam 51 and the second laser beam 61 from the first laser sensor 50 and the second laser sensor 60, respectively. In proportion to the distance to the irradiation position, as shown in FIGS. 2A and 2B, it changes so as to draw a diagram in which the upright portion a, the parallel portion b, and the inclined portion c are combined.

  Specifically, in the first laser sensor 50, since the first laser beam 51 is emitted from the casing 10 toward the rear side in the rotation direction of the rotor blade 30, the first laser beam 51 is first rotated. The front side surface 32 of the moving blade 30 is not irradiated but irradiated to the blade top portion 31 (corresponding to the upright portion a in FIG. 2A), and the irradiation position is the blade of the moving blade 30 as the moving blade 30 rotates. It moves to the rear side in the rotational direction on the surface of the top portion 31 (corresponding to the parallel portion b in FIG. 2A), and further moves to the rear side surface 33 of the moving blade 30 and moves on the rear side surface 33 to the blade root side ( This corresponds to the inclined portion c in FIG.

  On the other hand, in the second laser sensor 60, since the second laser light 61 is emitted from the casing 10 toward the rear side in the rotation direction of the moving blade 30, the second laser light 61 is first rotated. 30 is irradiated to the blade root portion side of the front side surface 32 of the blade 30, and the irradiation position moves to the blade top portion 31 side on the front side surface 32 of the blade 30 as the blade 30 rotates (the upright portion in FIG. 2B). a), and further moves onto the surface of the blade top portion 31 of the moving blade 30 and moves backward on the surface of the blade top portion 31 (corresponding to the parallel portion b in FIG. 2B). Passes through the path of the second laser beam 61 without being irradiated with the second laser beam 61 on the rear side surface 33 (corresponding to the inclined portion c in FIG. 2B).

In the data processing unit 80, based on the detection results of the first laser sensor 50 and the second laser sensor 60, the rotating blade 30 passes through the path of the first laser beam 51 at a predetermined position and then passes through the predetermined path. A passing time T _X until the second laser beam 61 passes through a path that is a predetermined position different from the position is calculated.

In the present embodiment, the time when the moving blade 30 passes through the path of the first laser beam 51 and the path of the second laser beam 61 respectively, and the predetermined position on the moving blade 30 is the path of the first laser beam 51 and the second laser beam. Times T _X1 and T _X2 reaching the path of the light 61 are set. Specifically, at the times T _X1 and T _X2 when the rotational direction front end 34 of the blade tip 31 of the moving blade 30 reaches the path of the first laser beam 51 and the path of the second laser beam 61, respectively. Yes (see FIG. 3), as shown in FIG. 2 respectively, the front end of the parallel part b in the first laser sensor 50 (the right end in FIG. 2) and the front end of the parallel part b in the second laser sensor 60 Is the time difference T _X (= T _X2 −T _X1 ).

Further, as shown in FIG. 3, the predetermined portion of the moving blade 30 (in this embodiment, the front end 34 in the rotational direction of the blade top 31) is located at a predetermined distance C from the inner peripheral surface of the casing 10. Corresponding to passing the first reference point M ₁ on the path of the first laser beam 51, the second reference point M ₂ on the path of the second laser beam 61 located at a predetermined distance C from the inner peripheral surface of the casing 10. The phase to be calculated is calculated from the rotation phase of the rotor shaft 20 by the tachometer 70, and the rotation time for the predetermined phase of the rotor blade 30 is defined as a reference passage time T _M (= T _M2 −T _M1 ).

Then, the tip clearance D is calculated from the ratio (X = T _M / T _X ) between the passing time T _X and the reference passing time T _M obtained above by the tip clearance calibration formula of the following formula (1).

  D = aX + b (1)

  Here, the coefficient a and the coefficient b are chip clearance calibration values in the chip clearance calibration formula of the formula (1), respectively, and are determined by the mounting angles, mounting positions, etc. of the first laser sensor 50 and the second laser sensor 60. It is.

  Details of how to obtain the tip clearance calibration values a and b in the tip clearance calibration equation of equation (1) will be described below. In this embodiment, the tip clearance calibration values a and b are obtained by using a rotor shaft and a moving blade different from the rotor shaft 20 and the moving blade 30 described above.

  First, instead of the rotor shaft 20 and the moving blade 30 in the axial flow rotary machine 1 described above, as shown in FIG. The blade 130 </ b> A and the second simulated blade 130 </ b> B are rotatably assembled to the casing 10 to which the first laser sensor 50 and the second laser sensor 60 are attached.

  Actually, after attaching the first laser sensor 50 and the second laser sensor 60 to the casing 10 and before attaching the rotor shaft 20 and the moving blade 30, the simulated rotor shaft 120, the first simulated moving blade 130A. It is preferable to attach the second simulated moving blade 130B and complete the work of obtaining the tip clearance calibration values a and b described below.

  The simulated rotor shaft 120 is a shaft body that is concentric with the casing 10 and is assembled so as to be rotatable. The first simulated moving blade 130A and the second simulated moving blade 130B are rotary blades that are installed on the outer periphery of the simulated rotor shaft 120 and are rotated together with the simulated rotor shaft 120 in the casing 10, and have a length in the radial direction ( (Wing length) shall be different from each other. The first simulated moving blade 130A and the second simulated moving blade 130B have a blade shape, particularly a blade, so that the reflection of the first laser light 51 and the second laser light 61 is equivalent to the moving blade 30 described above. It is preferable that the top portions 131A and 131B have the same shape.

  In the casing 10 in which the simulated rotor shaft 120, the first simulated moving blade 130A, and the second simulated moving blade 130B are assembled, the first laser sensor 50 is connected to the first laser sensor 50 in the same manner as the casing 10 including the moving blade 30 described above. The first laser light 51 is emitted toward the rotational direction side of the first simulated moving blade 130A and the second simulated moving blade 130B, and the second laser sensor 60 rotates the first simulated moving blade 130A and the second simulated moving blade 130B. The second laser beam 61 is emitted toward the opposite side.

The first simulated moving blade 130A is rotated work with simulated rotor shaft 120, Tsubasaitadaki portion (tip) 131A of the first simulated moving blades 130A, the diameter of the first laser beam 51 away from the reference point M ₁ by a distance L _A The light passes through a passing point T _LA1 on the road and passes through a passing point T _LA2 on the path of the second laser beam 61 that is also separated from the reference point M ₂ by the same distance L _A.

On the other hand, the second simulated moving blade 130B is rotated together with the simulated rotor shaft 120 and the first simulated moving blade 130A, but the blade length of the second simulated moving blade 130B is different from the first simulated moving blade 130A. top (chip) 131B, the second laser passes through the passing point T _LA1 on path of the first laser beam 51 away from the reference point M ₁ by a distance L _B, separated by same distance L _B from the reference point M ₂ through the passing point T _LA2 on path of the light 61.

In the casing 10 in which the simulated rotor shaft 120, the first simulated moving blade 130A, and the second simulated moving blade 130B are assembled as described above, the first simulated moving blade 130A and the first simulated moving blade 130A The relationship between the reflected light quantity v and the time t when the second simulated moving blade 130B crosses the path of the first laser beam 51 and the path of the second laser beam 61 (this is the same as FIG. 2 and is not shown). Is detected by the data processing unit 80, and the passing times T _LA and T _{LB of} the first simulated moving blade 130A and the second simulated moving blade 130B are calculated from the detection result.

The tip clearance calibration values a and b in the tip clearance calibration equation (1) are the shape setting values of the first simulated rotor blade 130A and the second simulated rotor blade 130B in the following equations (2) and (3). The distances L _A and L _B from the reference points M ₁ and M ₂ indicating the respective blade lengths and the passage times T _LA and T _LB that are values calculated by the data processing unit 80 are substituted. In Equation (2), T = T _LA / T _LB.

a = (L _B −L _A ) / (T−1) (2)

b = L _A -ac (3)

  The tip clearance calibration values a and b obtained as described above are stored in the data processing unit 80, and the tip in the gap 40 between the casing 10 and the moving blade 30 in the axial-flow rotating machine 1 provided with the rotor shaft 20 and the moving blade 30 described above. Find clearance D. That is, the simulated rotor shaft 120, the first simulated moving blade 130A, and the second simulated moving blade 130B are removed from the casing 10, the original rotor shaft 20 and the moving blade 30 are assembled to the casing 10, and the axial-flow rotating machine 1 is operated. Thus, the chip clearance D is measured.

  Measurement of the tip clearance D in the axial-flow rotating machine 1 according to the present embodiment will be described below. As described above, the tip clearance D is calculated from the detection results of the first laser sensor 50 and the second laser sensor 60 and the detection result of the tachometer 70 using the above-described tip clearance calibration values a and b. ) Chip clearance calibration formula.

In the data processing unit 80, the first laser sensor 50 and the second laser sensor 60 cause the front end 34 in the rotational direction of the blade top 31 of the moving blade 30 to be on the path of the first laser beam 51 and the second laser beam 61, respectively. Times T _X1 and T _X2 reaching the path of the first laser beam 51 are detected, and the passage time T _X (= T _X2) from when the moving blade 30 crosses the path of the first laser beam 51 to the path of the second laser beam 61 -T _X1 ) is calculated (see FIGS. 2 and 3).

Further, the rotation meter 70 detects a phase corresponding to the rotation direction front end portion 34 of the blade tip portion 31 of the moving blade 30 passing through the first reference point M ₁ and the second reference point M _2, and the phase. A reference passage time T _M for rotating the difference is calculated (see FIG. 3).

Then, from the ratio (X = T _M / T _X ) between the passage time T _X and the reference passage time T _M obtained as described above, the tip clearance calibration equation (1) using the tip clearance calibration values a and b is used. The tip clearance D is calculated.

  As described above, the tip clearance D can be obtained in the axial-flow rotating machine 1 provided with the tip clearance measuring device according to the present embodiment. According to the present embodiment, the moving blade 30 only needs to reflect the first laser light 51 and the second laser light 61 by the first laser sensor 50 and the second laser sensor 60, and therefore the material of the object to be measured. Is not restricted, and is not affected by the environmental temperature.

  Further, as in the present embodiment, the first laser light 51 and the second laser light 61 are transmitted from the installation position of the first laser sensor 50 and the second laser sensor 60 to the center position of the casing 10 and the rotor shaft 20. By installing the first laser sensor 50 and the second laser sensor 60 on the casing 10 so as to cross each other, the first laser light 51 and the second laser light 61 are emitted to a small range. Among the plurality of moving blades 30, it is easy to specify the moving blade 30 that is the measurement target. Therefore, the possibility of misidentifying the moving blade 30 to be measured can be reduced.

  Further, the tip clearance calibration values a and b are obtained by using the simulated rotor shaft 120 different from the rotor shaft 20 and the moving blade 30, the first simulated moving blade 130A and the second simulated moving blade 130B, and the first laser sensor 50 and Since the calculation is performed in the casing 10 in which the second laser sensor 60 is already installed, mounting errors of the first laser sensor 50 and the second laser sensor 60 do not affect the calculated value of the chip clearance D. That is, an installation error or the like of the first laser sensor 50 and the second laser sensor 60 can be allowed. Therefore, more accurate tip clearance D can be measured.

Of course, in the tip clearance measuring device according to the present invention, the position where passage is detected by the first laser sensor 50 and the second laser sensor 60 is not limited to the front end 34 in the rotational direction of the blade top 31 of the moving blade 30. For example, the passage detection point a rotationally trailing side end portion of the Tsubasaitadaki 31 in the blades 30 may be as the passing time T _X a transit time T _Y in FIG. 2, the rotation direction ahead of Tsubasaitadaki portion 31 of rotor blade 30 With the side end 34 and the rotation direction rear side end as passage detection locations, the passage time T _X may be obtained by removing the thickness of the moving blade 30 from the passage time T _Z in FIG.

  Further, in the tip clearance measuring apparatus according to the present invention, when the tip clearance calibration values a and b are obtained, the first simulated moving blade 130A and the second simulated moving blade 130B having different blade lengths are used as in the present embodiment. It is not limited to. For example, when obtaining the tip clearance calibration values a and b, a test blade having a variable blade length, that is, a radial length may be used.

In addition, the installation angles of the first laser sensor and the second laser sensor in the chip clearance measuring apparatus according to the present invention are not limited to the present embodiment, and the first laser light 51 of the first laser sensor 50 and the second laser sensor 60. Any of the second laser beams 61 may be emitted in a direction that does not coincide with the radial direction of the rotor shaft 20. By making one of the first laser beam 51 and the second laser beam 61 not coincide with the radial direction of the rotor shaft 20, the radial position of the blade tip portion 31 of the rotor blade 30, that is, the tip clearance D is changed. In this case, since the passage time T _X when the path of the first laser beam 51 and the second laser beam 61 crosses changes, the chip clearance D corresponding to the passage time T _X can be obtained.

  An axial-flow rotating machine provided with a tip clearance measuring device according to Embodiment 2 of the present invention will be described with reference to FIGS.

  The axial-flow rotating machine according to the present embodiment has the same configuration as that of the first embodiment except for the mounting angles of the first laser sensor 50 and the second laser sensor 60 with respect to the casing 10 in the first embodiment. Are denoted by the same reference numerals and redundant description is omitted.

  As shown in FIG. 5, the axial-flow rotating machine 1 in the present embodiment is a measuring device for accurately measuring the tip clearance D, and detects that the rotating moving blade 30 has passed a predetermined position. A first laser sensor 250; a second laser sensor 260 for detecting that the rotating moving blade 30 has passed a predetermined position different from the predetermined position; and the rotational speed of the moving blade 30, that is, the rotor shaft 20 A tachometer 70 that detects the number of revolutions, a first laser sensor 250, a second laser sensor 260, and a data processing unit 80 that calculates a chip clearance D from the detection results of the tachometer 70 are provided.

  The first laser sensor 250 and the second laser sensor 260 have an emission unit (not shown) that emits the first laser beam 251 and the second laser beam 261, respectively, and the emitted first laser beam 251 and the second laser beam 261 move. A light receiving portion (not shown) that senses light reflected by the blade 30 (reflected light), and the rotating blade 30 that rotates is traversed by the first laser light 251 and the second laser light 261 that are emitted. The emitting part is installed toward the inner peripheral side of the casing 10 so that the laser light 251 and the second laser light 261 are emitted toward the rotation trajectory range of the rotor blade 30, that is, toward the inner peripheral side of the casing 10 (the lower side in FIG. 5). Is done.

  In the present embodiment, the first laser sensor 250 emits the first laser beam 251 from the casing 10 side toward the side opposite to the rotation direction of the rotor blade 30 from the center of the rotor shaft 20 (left side in FIG. 5). The second laser sensor 260 is installed so as to be inclined with respect to the radial direction of the casing 10. 5 is arranged so as to be inclined toward the radial direction of the casing 10 so as to be emitted toward the right side in FIG.

  That is, the first laser sensor 250 and the second laser sensor 260 are installed in the casing 10 so as to open toward the inner peripheral side of the casing 10 so that the first laser beam 251 and the second laser beam 261 do not intersect.

  The amount of reflected light (the amount of reflected light) with respect to time t obtained by the first laser sensor 250 and the second laser sensor 260 when the rotating blade 30 is rotated across the path of the first laser beam 251 and the path of the second laser beam 261. The relationship of the amount of light (v) is shown in FIGS. 6 (a) and 6 (b), respectively. The amount of reflected light v detected by a light receiving unit (not shown) of the first laser sensor 250 and the second laser sensor 260 is the first laser beam 251 and the second laser beam 261 from the first laser sensor 250 and the second laser sensor 260, respectively. As shown in FIGS. 6A and 6B, the distance to the irradiation position changes so as to draw a diagram in which the upright part a, the parallel part b, and the inclined part c are combined.

  Specifically, in the first laser sensor 250, the first laser light 251 is emitted from the casing 10 side toward the opposite side of the rotating direction of the rotor blade 30, so the first laser light 251 is first rotated. The blade root side of the rear side surface 33 of the moving blade 30 is irradiated, and the irradiation position moves on the rear side surface 33 of the moving blade 30 to the blade top portion 31 side as the moving blade 30 rotates (in FIG. 6A). (Corresponding to the inclined portion c), and further moving onto the surface of the blade top portion 31 of the moving blade 30 and moving backward on the surface of the blade top portion 31 (corresponding to the parallel portion b in FIG. 6A). The blade 30 passes through the path of the second laser beam 261 without being irradiated with the second laser beam 261 on the rear side surface 33 (corresponding to the upright portion a in FIG. 6A).

  On the other hand, in the second laser sensor 260, since the second laser light 261 is emitted from the casing 10 toward the rear side in the rotation direction of the moving blade 30, the second laser light 261 is first rotated. 30 is not irradiated on the front side surface 32 of the blade 30 but irradiated on the blade top portion 31 (corresponding to the upright portion a in FIG. 6A), and the irradiation position is the blade top portion 31 of the blade 30 as the blade 30 rotates. 6 is moved to the rear side in the rotational direction (corresponding to the parallel part b in FIG. 6A), further moved to the rear side surface 33 of the moving blade 30 and moved to the blade root side on the rear side surface 33 (FIG. 6). (Corresponding to the inclined portion c in (a)).

In the data processing unit 80, based on the detection results of the first laser sensor 250 and the second laser sensor 260, the rotating blade 30 passes through the path of the first laser beam 251 at a predetermined position and then passes through the predetermined path. The passage time T _X until the second laser beam 261 passes through the path that is a predetermined position different from the position is calculated.

In the present embodiment, the time when the moving blade 30 passes the path of the first laser beam 251 and the path of the second laser beam 261 respectively, and the predetermined position on the moving blade 30 passes the path of the first laser beam 251 and the second laser beam. The times T _X1 and T _X2 are reached on the path of the light 261. Specifically, at the time T _X1 and T _X2 when the rotational direction front end 34 of the blade tip 31 of the moving blade 30 reaches the path of the first laser beam 251 and the path of the second laser beam 261, respectively. 6, as shown in FIG. 6, the time difference T _X (between the front end of the parallel portion b in the first laser sensor 250 (the right end in FIG. 6) and the front end of the parallel portion b in the second laser sensor 260. = T _X1 -T _X2 ).

  Since the tip clearance calibration formula and the tip clearance calibration values a and b in the formula (1) are the same as those in the first embodiment, description thereof will be omitted.

  According to the present embodiment, since the first laser beam 251 and the second laser beam 261 do not intersect, it is not necessary to consider the position of the intersection between the first laser beam 251 and the second laser beam 261, and the first laser sensor The restriction on the installation angle of 250 and the second laser sensor 260 can be relaxed.

  An axial-flow rotating machine provided with a tip clearance measuring apparatus according to Embodiment 3 of the present invention will be described with reference to FIGS.

  The axial-flow rotating machine according to the present embodiment has the same configuration as that of the first embodiment except for the mounting angles of the first laser sensor 50 and the second laser sensor 60 with respect to the casing 10 in the first embodiment. Are denoted by the same reference numerals and redundant description is omitted.

  As shown in FIG. 7, the axial-flow rotating machine 1 in the present embodiment is a measuring device for accurately measuring the tip clearance D, and detects that the rotating moving blade 30 has passed a predetermined position. A first laser sensor 350, a second laser sensor 360 for detecting that the rotating rotor blade 30 has passed a predetermined position different from the predetermined position, and the rotational speed of the rotor blade 30, that is, the rotor shaft 20 A tachometer 70 for detecting the number of revolutions, a first laser sensor 350, a second laser sensor 360, and a data processing unit 80 for calculating a chip clearance D from the detection results of the tachometer 70 are provided.

  The first laser sensor 350 and the second laser sensor 360 are respectively configured to emit a first laser beam 351 and a second laser beam 361 that are not shown, and the emitted first laser beam 351 and the second laser beam 361 are moved. And a light receiving unit (not shown) that senses light reflected by the blade 30 (reflected light), and the rotating blade 30 is rotated so that the first laser beam 351 and the second laser beam 361 are emitted. The emitting part is installed toward the inner peripheral side of the casing 10 so that the laser beam 351 and the second laser light 361 are emitted toward the rotation trajectory range of the rotor blade 30, that is, toward the inner peripheral side of the casing 10 (the lower side in FIG. 7). Is done.

  In the present embodiment, the first laser sensor 350 emits the first laser beam 351 from the casing 10 side toward the rotation direction side (right side in FIG. 7) of the rotor blade 30 from the center of the rotor shaft 20. As described above, the second laser sensor 360 is installed so as to be inclined with respect to the radial direction of the casing 10. It is installed inclining with respect to the radial direction of the casing 10 so as to be emitted toward the right side).

  The first laser sensor 350 and the second laser sensor 360 are installed in the casing 10 so as to open toward the inner peripheral side of the casing 10 so that the first laser beam 351 and the second laser beam 361 do not intersect. Of course, as in the first embodiment, the first laser sensor 350 and the second laser sensor 360 may be installed so that the first laser beam 351 and the second laser beam 361 intersect.

  The amount of reflected light (the amount of reflected light) with respect to the time t obtained by the first laser sensor 350 and the second laser sensor 360 when the rotating blade 30 crosses the path of the first laser beam 351 and the path of the second laser beam 361. The relationship of the amount of light (v) is shown in FIGS. 8 (a) and 8 (b), respectively. The amount of reflected light v detected by the light receiving portions (not shown) of the first laser sensor 350 and the second laser sensor 360 is the first laser light 351 and the second laser light 361 from the first laser sensor 350 and the second laser sensor 360, respectively. As shown in FIGS. 8A and 8B, the distance to the irradiation position changes so as to draw a line diagram combining the upright portion a, the parallel portion b, and the inclined portion c.

  Specifically, in the first laser sensor 350, the first laser light 351 is emitted from the casing 10 toward the rotation direction of the rotor blade 30, and therefore the first laser light 351 is first rotated. The front side surface 32 of the blade 30 is not irradiated but irradiated to the blade top portion 31 (corresponding to the upright portion a in FIG. 8A), and the irradiation position is the blade top portion of the blade 30 as the moving blade 30 rotates. 31 moves to the rear side in the rotational direction (corresponding to the parallel part b in FIG. 8A), and further moves to the rear side surface 33 of the moving blade 30 and moves to the blade root side on the rear side surface 33 (see FIG. 8 (a) corresponding to the inclined portion c).

  On the other hand, in the second laser sensor 360, since the second laser light 361 is emitted from the casing 10 toward the rotating direction of the moving blade 30, the second laser light 361 is first rotated. The front side surface 32 of the moving blade 30 is not irradiated but irradiated to the blade top portion 31 (corresponding to the upright portion a in FIG. 8B). It moves to the rear side in the rotational direction (corresponding to the parallel part b in FIG. 8B), further moves to the rear side surface 33 of the moving blade 30 and moves to the blade root side on the rear side surface 33 (FIG. 8 ( equivalent to the inclined portion c in b).

In the data processing unit 80, based on the detection results of the first laser sensor 350 and the second laser sensor 360, the rotating blade 30 passes through the path of the first laser light 351 at a predetermined position and then passes through the predetermined path. A passing time T _X until the second laser beam 361 passes through a path that is a predetermined position different from the position is calculated.

In the present embodiment, the time when the moving blade 30 passes through the path of the first laser beam 351 and the path of the second laser beam 361 respectively, and the predetermined position on the moving blade 30 passes the path of the first laser beam 351 and the second laser beam. The times T _X1 and T _X2 are reached on the path of the light 361. Specifically, at the time T _X1 and T _X2 when the rotational direction front end 34 of the blade tip 31 of the moving blade 30 reaches the path of the first laser beam 351 and the path of the second laser beam 361, respectively. As shown in FIG. 8, the time difference T _X (between the front end of the parallel portion b in the first laser sensor 350 (the right end in FIG. 8) and the front end of the parallel portion b in the second laser sensor 360. = T _X2 -T _X1 ).

  Since the tip clearance calibration formula and the tip clearance calibration values a and b in the formula (1) are the same as those in the first embodiment, description thereof will be omitted.

According to the present embodiment, the times T _X1 and T _X2 in the detection results of the first laser sensor 350 and the second laser sensor 360 are the front ends of the parallel portion b as shown in FIGS. That is, it is the time at the intersection of the parallel part b and the upright part a (the upper end part of the upright part a), and even when the amount of reflected light v changes, the time does not change, so that a measurement error hardly occurs. That is, even when the amount of reflected light v changes due to dirt on the measurement surface of the moving blade 30, the times T _X1 and T _X2 in the detection results of the first laser sensor 350 and the second laser sensor 360 do not change, resulting in measurement errors. Can be reduced.

  In the present embodiment, the first laser beam 351 and the second laser beam 361 do not intersect with each other, so that the restriction on the installation angle of the first laser sensor 350 and the second laser sensor 360 can be relaxed. Of course, as in the first embodiment, the first laser sensor 350 and the second laser sensor 360 may be installed so that the first laser beam 351 and the second laser beam 361 intersect.

1 Axial Flow Rotating Machine 10 Casing 20 Rotor Shaft 30 Rotor Blade 31 Rotor Top (Tip)
31a Trajectory of blade tip (tip) 32 of rotor blade Front side surface 33 of rotor blade Rotational rear side surface 40 of rotor blade Gap 50 First laser sensor 51 First laser beam 60 Second laser sensor 61 Second laser beam 70 Tachometer 80 Data processor 120 Simulated rotor shaft 130A First simulated moving blade 130B Second simulated moving blade

Claims (4)

The rotor blade in an axial-flow rotating machine comprising: a cylindrical casing; a rotor shaft rotatably supported in the casing; and a rotor blade planted on the outer periphery of the rotor shaft and rotated in the casing together with the rotor shaft. A tip clearance measuring device for measuring a tip clearance which is a distance between a blade top and an inner peripheral surface of the casing,
A first laser sensor installed in the casing, capable of detecting that the moving blade has passed a predetermined position by receiving reflected light reflected by the moving blade by emitting laser light in a predetermined direction;
The moving blade is placed in the casing and emits a laser beam in a predetermined direction different from the predetermined direction and receives reflected light reflected by the moving blade, so that the moving blade has a predetermined position different from the predetermined position. A second laser sensor capable of detecting passing, and
A tachometer capable of detecting the rotation speed of the rotor blade or the rotor shaft;
The passage time from the predetermined position of the moving blade to the different predetermined position is calculated from the detection results of the first laser sensor and the second laser sensor, and the predetermined phase of the moving blade detected by the tachometer A data processing unit for calculating a minute clearance, and calculating a tip clearance by a tip clearance calibration formula composed of the passage time, the rotation time, and a tip clearance calibration value,
The tip clearance calibration value is obtained by assembling a simulated moving blade different from the moving blade into the casing.   The first laser sensor and the second laser sensor are inclined with respect to each other so that the first laser beam and the second laser beam intersect in a direction perpendicular to the axial direction of the casing, 2. The chip clearance measuring device according to claim 1, wherein the tip clearance measuring device is installed so that an intersection of the laser beam and the second laser beam is located on an inner peripheral side with respect to a blade top portion of the moving blade.   The first laser sensor and the second laser sensor are moved toward the inner circumferential side of the casing so that the first laser beam and the second laser beam do not intersect in a direction perpendicular to the axial direction of the casing. 2. The chip clearance measuring device according to claim 1, wherein the chip clearance measuring device is installed so as to be inclined with respect to each other.   The said 1st laser sensor and said 2nd laser sensor are installed toward the rotation direction side of the said moving blade rather than the center of the said casing, The Claim 1 thru | or 3 characterized by the above-mentioned. Tip clearance measuring device.

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