JP5944295B2 - Low speed balance method and low speed balance device - Google Patents

Description

  Embodiments described herein relate generally to a low speed balance method and a low speed balance apparatus.

  In gas turbines, a low speed balance test is performed prior to incorporating the rotor into the equipment to remove the imbalance caused by blade replacement.

  The low-speed balance test is a balance test that is performed at a sufficiently low speed relative to the rated speed of the gas turbine, and is a balance test as a rigid rotor that does not consider elastic deformation due to the vibration mode of the rotor at a high speed. is there.

  A counterweight (balance weight) is attached to two weight attachment correction surfaces provided in the vicinity of both ends of the rotor to remove residual unbalance remaining in the rotor.

  In a turbine having a laminated rotor such as a gas turbine, there are two types of imbalance after the turbine blades are replaced. In other words, due to the imbalance caused by the variation in the circumferential moment of the turbine blades implanted in each wheel part by turbine blade replacement, and the state of rotor stacking over time from the balance state at the previous low-speed balance It is an imbalance due to the generated rotor bending. Hereinafter, the former is referred to as rotor blade exchange unbalance, and the latter is referred to as rotor bending unbalance.

Japanese Patent No. 477594

  FIG. 13 is a front view showing the shape of the rotor of the gas turbine and the position of the correction surface, and shows an example of a gas turbine having three-stage turbine blades.

  The rotor 1 has a rotor compressor side portion 1a and a rotor turbine side portion 1b, which are coupled by a coupling 4 at the center in the axial direction. The rotor 1 is mounted on the first bearing 8 and the second bearing 9 in the first bearing mounting portion 2 and the second bearing mounting portion 3, respectively, and rotates. The rotor turbine side portion 1 b has a first stage turbine blade 5, a second stage turbine blade 6 and a third stage turbine blade 7.

The rotor 1 has six correction surfaces to which balance weights are added for correcting unbalance from the central axis. That is, from the coupling 4 to the compressor side,
A first correction surface 11 at the inlet of the rotor compressor side portion 1a, a second correction surface 12 at the outlet of the rotor compressor side portion 1a, and a third correction surface 13 near the coupling 4 are provided. .

  Further, on the turbine side of the coupling 4, a fourth correction surface 14 near the first stage turbine blade 5, a fifth correction surface 15 near the second stage turbine blade 6, and a vicinity near the third stage turbine blade 7. A sixth correction surface 16 is provided.

  FIG. 14 is a flowchart showing the steps of the low-speed balance method according to the conventional method. The case where all of the first stage turbine blade 5, the second stage turbine blade 6, and the third stage turbine blade 7 are updated is shown as an example.

  First, as a preparation, the balance weight at the previous turbine blade replacement in each paragraph is removed (S1). After step S1, the first stage turbine blade 5, the second stage turbine blade 6 and the third stage turbine blade 7 are removed (S2).

  After step S2, turning is sufficiently performed (S3), and then the two-surface correction balance is performed (S4). Specifically, the imbalance is measured in a low-speed rotation state, and a balance weight is added to the correction surface at the end closest to the compressor and the correction surface at the end closest to the turbine.

  After step S4, the second stage turbine blade 6 is attached (S5). After step S5, turning is performed (S6), imbalance is measured in a low-speed rotation state (S7), and a balance weight is added to the correction surface in the second stage turbine blade 6 (S8).

  After step S8, the first stage turbine blade 5 is attached (S9). After step S9, turning is performed (S10), an unbalance is measured in a low-speed rotation state (S11), and a balance weight is added to the correction surface in the first stage turbine blade 5 (S12).

  After step S12, the third stage turbine rotor blade 7 is attached (S13). After step S13, turning is performed (S14), imbalance is measured in a low-speed rotation state (S15), and a balance weight is added to the correction surface in the third stage turbine rotor blade 7 (S16).

  After step S16, turning is performed (S17), and then the unbalance is measured in the low-speed rotation state as the two-surface correction balance (S18). After step S18, the balance weight is distributed to the correction surface provided between the correction surface at the end closest to the compressor and the correction surface at the end closest to the turbine side, and is added to each (S19). .

  After step S19, turning is performed (S20), and then the unbalance is measured in the low-speed rotation state as the final balance of the two surfaces (S21). After step S21, a balance weight is added to the correction surface at the end closest to the compressor and the correction surface at the end closest to the turbine. Further, the rotor run-out measurement is finally performed (S22).

  In this manner, step S4, step S7, step S11, step S15, step S18, and step S21, and conventionally, balance confirmation, that is, measurement of unbalance, is performed at six low-speed revolutions.

  Therefore, an object of the embodiment of the present invention is to enable low-speed balance with few steps without degrading accuracy.

  In order to achieve the above-described object, an embodiment of the present invention is a low-speed balance method that is performed at low speed rotation in order to regenerate unbalance around the rotation axis of the rotor in a turbine having a rotor in which disks are laminated in the axial direction. A blade removal step for removing all stages of turbine blades, a blade attachment step for attaching new turbine blades at each stage, a first balance measurement step for measuring an unbalance in a low-speed rotation state, and the first From the measurement results in the balance measurement step, unbalance separation that separates unbalance into rotor bending unbalance and rotor blade replacement unbalance is performed, and unbalance separation that sets the balance weight amount and position to be added to each correction surface Based on the result of the evaluation step and the unbalance separation evaluation step, a balance weight is applied to each correction surface. A first addition step to be applied; a second balance measurement step for measuring an unbalance in a low-speed rotation state after the first addition step; and a correction surface at both ends after the second balance measurement step. And a final addition step of adding a balance weight to the balance.

  In addition, an embodiment of the present invention is a low-speed balance device that performs low-speed rotation in a turbine having a rotor in which discs are laminated in the axial direction to regenerate unbalance around the rotation axis of the rotor, and includes at least two bearings A vibration sensor provided on each of the two bearings, a low-speed balancer coupled to a rotor of a rotating device mounted on the bearing to rotate the rotor at a low speed, and a signal from the vibration sensor as inputs. An evaluation device that performs unbalance evaluation, and the evaluation device performs unbalance measurement at a first measurement point that is a measurement point on the turbine exhaust side and a second measurement point that is a measurement point on the anti-turbine side. A database of actual machine data related to the results, a rotor bending unbalanced second vector at the second measurement point, and the database The rotor bending unbalance first vector obtained by multiplying the rotor bending unbalance second vector by a predetermined magnification obtained, and the rotor bending unbalance first vector is subtracted from the unbalance measurement result of the first measurement point. The rotor blade unbalance vector, the rotor bending unbalance first vector, and the rotor bending unbalance second vector added to the rotor bending unbalance total vector are calculated, and each unbalance evaluation result is calculated based on the unbalance evaluation result. An intermediate correction surface weight calculation unit that distributes the balance to each correction surface.

  According to the embodiment of the present invention, it is possible to achieve low speed balance with fewer steps without reducing accuracy.

It is a flowchart which shows the procedure of the low speed balance method which concerns on the 1st Embodiment of this invention. It is a front view for demonstrating the low speed balance method which concerns on the 1st Embodiment of this invention. It is a table | surface which shows the example of the unbalance characteristic of the correction surface of the compressor side end, and the correction surface of a turbine side end in each unit of rotor bending unbalance for demonstrating the low speed balance method which concerns on the 1st Embodiment of this invention. is there. It is a vector diagram for demonstrating the method of isolate | separating a rotor bending imbalance and a rotor blade exchange imbalance from a both-ends weight state in the low speed balance method which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the procedure of the isolation | separation evaluation step in the low speed balance method which concerns on the 1st Embodiment of this invention. FIG. 3 is a region diagram showing a method for distributing blade replacement unbalance in the low speed balance method according to the first embodiment of the present invention. It is a figure which shows the vibration risk calculation result by embodiment calculated | required from the results by the conventional method for demonstrating the effect of the low speed balance method which concerns on the 1st Embodiment of this invention, (a) is plant A, (b) Is an example of plant B. It is an area diagram showing a simple distribution method of blade exchange imbalance as a modification of the first embodiment of the present invention. It is a block diagram which shows the low speed balance implementation apparatus for implementing the low speed balance method which concerns on the 2nd Embodiment of this invention. It is a front view which shows the attachment position of the dial gauge at the time of rotor runout state measurement on the balancer of the low speed balance method which concerns on the 2nd Embodiment of this invention. It is explanatory drawing which shows the calculation process of a rotor bending imbalance from the rotor run-out measurement in the low speed balance method which concerns on the 2nd Embodiment of this invention. It is explanatory drawing which shows the calculation process of the rotor bending imbalance only by the analysis in the low speed balance method which concerns on the 2nd Embodiment of this invention. It is a front view which shows the shape of the rotor of a gas turbine, and the position of a correction surface. It is a flowchart which shows the step of the low speed balance method by the conventional method.

  Hereinafter, a low speed balance method and a low speed balance device according to an embodiment of the present invention will be described with reference to the drawings. Here, the same or similar parts are denoted by common reference numerals, and redundant description is omitted.

[First Embodiment]
FIG. 1 is a flowchart showing the procedure of the low-speed balance method according to the first embodiment of the present invention.

  First, in order to remove the bending due to non-uniform temperature distribution or the like, the turning is performed with sufficient time. Turning is usually performed at a rotational speed of several revolutions per minute (S3). After step S3, the deflection in the radial direction is measured along the circumferential direction at each axial portion of the rotor 1 (S24).

  After step S24, the previous weight is removed (S1). Further, all stages of the turbine blades, that is, the first stage turbine blade 5, the second stage turbine blade 6 and the third stage turbine blade 7 are removed (S2).

  After step 2, a new second stage turbine blade 6 is attached (S5), a new first stage turbine blade 5 is attached (S9), and a new third stage turbine blade 7 is attached (S13).

  After step S13, that is, after replacing the turbine blades with new ones (S13) and sufficiently turning (S17), the first balance measurement is performed (S18). Here, the first balance measurement is a step of measuring unbalance at measurement points at both ends of the rotor 1 in a low-speed rotation state.

  Based on the result of the unbalance measurement in step S18, the two types of imbalance that are generated at the time of turbine blade replacement are separated into rotor bending unbalance and blade replacement unbalance and added to each part. The power weight is calculated (S30).

  After step S30, internal weight distribution is performed (S19). Here, the internal weight distribution is the attachment of the balance weight to the correction surfaces other than the first correction surface 11 sandwiched between the first correction surface 11 and the sixth correction surface 16.

  Specifically, the second correction surface mounting balance weight 22 and the third correction surface are attached to the second correction surface 12, the third correction surface 13, the fourth correction surface 14, the fifth correction surface 15, and the sixth correction surface 16, respectively. In this adjustment, the balance weight 23, the fourth correction surface attachment balance weight 24, the fifth correction surface attachment balance weight 25, and the sixth correction surface attachment balance weight 26 are attached. The attachment of the balance weight includes a case where the weight is zero, that is, not attached depending on the correction surface.

  After step S19, the turning is sufficiently performed (S20), and then the second balance measurement is performed (S21). In the second balance measurement, an unbalance at the measurement points at both ends of the rotor 1 is measured.

  After the second balance measurement step S21, weight distribution at both ends is performed (S23). Here, the weight distribution at both ends is an adjustment in which the first correction surface mounting balance weight 21 and the sixth correction surface mounting balance weight 26 are attached to the first correction surface 11 and the sixth correction surface 16, respectively, and the balance weight final adding step It is.

  In this embodiment, since the rotor shake measurement is performed in the initial step S24 and the recording remains, unlike the conventional method, the rotor shake measurement after the weight distribution at both ends may not be performed.

  FIG. 2 is a front view for explaining the low-speed balance method according to the first embodiment of the present invention. The rotor 1 is taken out from a casing (not shown), and the first bearing mounting portion 2 and the second bearing mounting portion 3 are respectively mounted on the first bearing mount 31a and the second bearing mount 31b of the low speed balance test apparatus. In the figure, only the measurement part of the low-speed balance test apparatus is illustrated.

  The rotor 1 can be driven in a turning state. The turning speed is usually about several revolutions per minute, for example. Further, the rotor 1 can be driven at a low rotational speed that is sufficiently higher than the turning speed but smaller than the rated speed. The low-speed rotation speed is usually about several hundred rotations per minute, for example.

  The first bearing equivalent member and the second bearing equivalent member are provided with an unbalance measuring unit 33a and an unbalance measuring unit 33b, respectively. The unbalance measuring unit 33a and the unbalance measuring unit 33b are, for example, vibration detectors.

  Signals from the unbalance measurement unit 33a and the unbalance measurement unit 33b are input to the unbalance calculation unit 34a and the unbalance calculation unit 34b, respectively. The unbalance calculation unit 34a and the unbalance calculation unit 34b evaluate the unbalance angle and size from the vibration waveform.

  The calculation of the unbalance angle and size is performed, for example, by Fourier transforming the measured vibration waveform (size / time) to extract the low-speed rotation speed component and comparing it with the low-speed rotation speed input (drive input). It is sufficient to calculate the circumferential angle and moment value.

  The unbalance measured by the unbalance measuring unit 33a and the unbalance measuring unit 33b and calculated by the unbalance calculating unit 34a and the unbalance calculating unit 34b is distributed according to the ratio of the distance from each moving blade to the correction surface. .

  Here, in the actual example of a certain plant, the detection ratio in the imbalance measuring unit 33a and the unbalance measuring unit 33b of the moving blade replacement imbalance is determined for the first stage turbine moving blade 5 in the unbalance measuring unit 33a. 18.5%, second stage turbine blade 6 is 8.3%, third stage turbine blade 7 is 0%, and the detection ratio in the imbalance measuring unit 33a is small, and the blade replacement unbalance Is mostly detected by the unbalance measuring unit 33b which is the rotor turbine side portion 1b.

  FIG. 3 is an example of unbalance characteristics of the correction surface of the compressor side end and the correction surface of the turbine side end in each unit of rotor bending unbalance for explaining the low speed balance method according to the first embodiment of the present invention. It is a table | surface which shows.

  “Eccentric moment ratio” in the table indicates the ratio of the eccentric moment due to the rotor bending unbalance at the correction surface provided at the turbine side to the eccentric moment due to the rotor bending unbalance at the correction surface provided at the compressor side end. . "Eccentric angle difference" indicates the difference between the eccentric angle due to the rotor bending unbalance at the correction surface provided at the compressor side end and the eccentric angle due to the rotor bending unbalance at the correction surface provided at the turbine side end. .

  In the results of the seven plants A to G, the average value of the “eccentric moment ratio” is 1.4. The average value of “eccentric angle difference” is 0 °. That is, on average, the eccentricity due to the rotor bending unbalance of the correction surface provided at the turbine side end is the same direction as the rotor bending unbalance of the correction surface provided at the compressor side end, and the eccentric moment is large. It can be seen that the value at the correction surface provided at the turbine side end is 1.4 times the value at the correction surface provided at the compressor side end.

  FIG. 4 is a vector diagram for explaining a method of separating the rotor bending unbalance and the rotor blade replacement unbalance from the both-ends weight state in the low speed balance method according to the first embodiment of the present invention. FIG. 5 is a flowchart showing the procedure of the separation evaluation step in the low speed balance method according to the first embodiment of the present invention.

  A method and a procedure for separating the rotor bending imbalance and the blade replacement imbalance will be described in detail below with reference to FIGS.

  When the two-surface correction balance is performed, the unbalance vector measured by the unbalance measurement unit 33a is <Bal-a>, and the unbalance vector measured by the unbalance measurement unit 33b is <Bal-b>. Further, these combined vectors are set to <Unb>.

  Based on the results, the unbalance vector <Bal-a> measured by the unbalance measuring unit 33a can be regarded as an unbalance caused by the rotor bending unbalance.

  Therefore, the unbalance vector <Bal-a> is set as the rotor bending unbalance first vector (S31).

  Further, according to actual results, most of the blade replacement unbalance is detected by the unbalance measuring unit 33b which is the rotor turbine side portion 1b. Further, based on the results, the unbalance vector <Bal-b> measured by the unbalance measuring unit 33b is an eccentricity 1.4 times larger than <Bal-a> as an unbalance component due to rotor bending unbalance. It can be regarded as having a vector component.

  That is, of the eccentric moment in the unbalance measuring unit 33b, the magnitude of the unbalance due to the rotor bending unbalance is 1.4 times the magnitude of the eccentric moment in the unbalance measuring unit 33a, and the eccentric angle in the unbalance measuring unit 33b. The eccentric angle in the unbalance measuring unit 33a can be regarded as 0 °.

  Therefore, as shown in FIG. 4, a vector having a magnitude of 1.4 times in the same direction as <Bal-a> is set as the rotor bending unbalance second vector (S32). Then, in addition to <Bal-a>, a rotor bending unbalance total vector is obtained (S33).

  Further, <Unb_blade>, which is a component obtained by removing <Bal-a> × 1.4 from <Bal-b>, is an eccentric vector due to the moving blade imbalance. Therefore, <Unb_blade> is set as a blade replacement unbalance vector (S34).

  As a result, the composite vector <Unb> is divided into an eccentric vector (<Bal-a> + <Bal-a> × 1.4) caused by rotor bending imbalance and an eccentric vector (< Unb_blade>).

  Based on the result of separating the eccentric vector due to rotor bending imbalance and the eccentric vector due to rotor blade imbalance, the distribution of the correction weight to each correction surface is calculated according to the type of each imbalance. (S35).

  FIG. 6 is a region diagram showing a method for distributing blade replacement unbalance in the low speed balance method according to the first embodiment of the present invention.

  Regarding the correction of the rotor bending unbalance, the balance weight for correction is distributed to each intermediate correction surface. However, with respect to the distribution ratio, the bending of the rotor 1 changes linearly from both ends of the rotor 1 and the coupling at the center. 4 is assumed to have the maximum distribution. From the past results, it can be assumed that this is the case.

  On the other hand, with regard to the correction of the moving blade replacement imbalance, since the variations of the fourth correction surface 14, the fifth correction surface 15, and the sixth correction surface 16 (see FIG. 13) cannot be predicted, they can be equally allocated to the respective correction surfaces. desirable. However, the balance weight can be reduced in weight by cutting, but there is a limit, so there is a practically practical minimum value. Let the minimum value of this balance weight be Wmin.

  Considering the existence of the minimum value, the allocation method to each of the fourth correction surface 14, the fifth correction surface 15, and the sixth correction surface 16 according to the value of the total weight W necessary for correcting the moving blade replacement imbalance Is set as shown in FIG.

  That is, when W is larger than three times Wmin, the fourth correction surface 14, the fifth correction surface 15, and the sixth correction surface 16 are allotted equally. When W is greater than twice Wmin and less than or equal to three times Wmin, the fourth correction surface 14 and the sixth correction surface 16 are evenly allocated. If W is greater than Wmin and less than or equal to twice Wmin, it is allocated only to the fifth modified surface 15. If W is smaller than Wmin, it is not attached to either. By clarifying the division in this way, the distribution can be calculated automatically.

  FIG. 7 is a diagram showing a vibration risk calculation result according to the embodiment obtained from the results of the conventional method for explaining the effect of the low-speed balance method according to the first embodiment of the present invention. (B) is an example of plant B.

  The total unbalance was analyzed by adding the balance results of each blade replacement, that is, the blade replacement unbalance, to the actual value of unbalance detected after the blade replacement and balancing, that is, the actual value of rotor bending unbalance. .

  FIG. 7 uses this result to calculate vibration values in the first bearing mount 31a and the second bearing mount 31b (see FIG. 2) when using the method in the present embodiment, and carried out in an actual plant. The difference is shown in comparison with the conventional performance.

  7A and 7B, the difference in amplitude is within 5 μmp-p at the maximum. For example, when 1/100 mmp-p is taken as a reference, 0.5 × 1/100 mmp Within -p. This indicates that the necessary accuracy is ensured.

  As described above, in the past, the unbalance measurement was performed in steps of one stage of turbine blade replacement. In this embodiment, the turbine blade replacement is performed at once, and the two-surface corrected balance result is used. This is a technique for appropriately distributing the correction weight by separating the rotor blade unbalance and the rotor bending unbalance.

  As a result, it is possible to perform low-speed balance with fewer steps without reducing accuracy, and balance work can be performed in a shorter process than before.

  In the present embodiment, the allocation method is divided according to the value of the total amount W of the weight necessary for the correction regarding the correction of the moving blade replacement imbalance. However, the present invention is not limited to this, and a simpler method may be used. Good.

  FIG. 8 is a region diagram showing a simple distribution method of moving blade replacement imbalance as a modified example of the first embodiment.

  In this modification, when W is larger than Wmin, the entire amount is allocated to the fifth correction surface 15 corresponding to the second stage turbine blade 6. When W is smaller than Wmin, the balance weight is not allocated to any correction surface, and the method is divided into two. This is based on the following grounds.

  First, the response sensitivity of the second bearing vibration at the rated speed is 1: 2: 3 for the first stage turbine blade 5, the second stage turbine blade 6, and the third stage turbine blade 7, respectively. It is in.

  Here, for example, the influence on vibration when the third stage turbine blade 7 is replaced will be considered. In the case of the equal mounting as shown in FIG. 6, assuming that the increment of vibration at the first stage turbine blade 5 is 1, 2 for the second stage turbine blade 6 and 3 for the third stage turbine blade 7. The total vibration increase is 6.

  On the other hand, in the case of this modification, since there are three fifth modified surfaces 15 corresponding to the second stage turbine rotor blades 6, 6 is similarly obtained by multiplying the sensitivity of 2. As a result, at the time of replacement of the turbine rotor blade, there is no significant difference in the vibration increase risk between the first embodiment and the present modification.

  Therefore, this modification is also effective in terms of further shortening the work process.

[Second Embodiment]
FIG. 9 is a configuration diagram showing a low-speed balance execution device for performing the low-speed balance method according to the second embodiment of the present invention.

  The low-speed balance execution device includes a first bearing mount 31a and a second bearing mount 31b, unbalance measurement units 33a and 33b, unbalance calculation units 34a and 34b, and a balance evaluation device 100.

  The rotor 1 is mounted on the first bearing mount 31a and the second bearing mount 31b. The rotor 1 is coupled to a low-speed balancer 32 and is configured to be driven by the low-speed balancer 32 and to rotate at a low speed.

  The first bearing mount 31a and the second bearing mount 31b are provided with unbalance measuring units 33a and 33b, respectively, and can measure a state such as vibration during rotation of the rotor 1 at a low speed. The measurement results from the unbalance measurement units 33a and 33b are input to the unbalance calculation units 34a and 34b, respectively, and an eccentric vector due to the unbalance is calculated. The results calculated by the unbalance calculation units 34 a and 34 b are input to the balance evaluation apparatus 100.

  The balance evaluation apparatus 100 includes an unbalance separation / weight calculation unit 51, each correction surface weight calculation unit 52, an output display unit 53, a database 54, and an input unit 55.

  In the unbalance separation / weight calculation unit 51, the eccentric vector calculated by the unbalance calculation units 34a and 34b is separated into an eccentric vector caused by rotor bending unbalance and an eccentric vector caused by moving blade replacement imbalance. .

  Further, the unbalance separation / weight calculation unit 51 calculates a balance weight for correcting the rotor bending unbalance and a balance weight for correcting the blade replacement unbalance based on the result of separating the unbalance.

  In each correction surface weight calculation unit 52, the balance weight for correcting the rotor bending unbalance and the balance weight for correcting the blade replacement unbalance calculated by the unbalance separation / weight calculation unit 51 are assigned to each correction surface. It is done.

  This result is displayed by the output display unit 53.

  The input unit 55 receives necessary data. The database 54 stores data necessary for balancing the rotor type, weight, dangerous speed data, and the like, and is used for calculating the weight of each correction surface.

  In addition, a dial gauge 41 that is movable in the axial direction of the rotor 1 is provided, and is configured to be able to measure the deflection of each part. The run-out measurement is performed on the low-speed balance execution device at the timing after turning and before implanting the turbine rotor blade.

  When the rotor runout is measured in the casing as in the past, rotor bending occurs due to the difference in the upper and lower rotor temperatures, and the rotor runout accuracy cannot be ensured. However, sufficient turning is performed on the gas turbine rotor low-speed balancer to remove the temporary bend. By carrying out in such a state, disturbance is further eliminated and highly accurate measurement is realized.

  The rotor shake measurement is performed, for example, every 45 ° in the circumferential direction by attaching a dial gauge 41 directly below the rotor 1 at, for example, ten or more rotor shake measurement points in the axial direction of the rotor 1.

  FIG. 10 is a front view showing a dial gauge mounting position at the time of rotor runout state measurement on the balancer of the low speed balance method according to the second embodiment of the present invention. It is necessary to determine the key phaser (reference point) 42 when measuring the distribution of the vibration in the circumferential direction of the rotor 1. The reference point 42 may be a specific direction on the structure of the rotor 1, for example.

  FIG. 11 is an explanatory diagram illustrating a calculation process of rotor bending unbalance from rotor run-out measurement in the low speed balance method according to the second embodiment of the present invention.

  First, an eccentric amount and angle for each measurement point, that is, an eccentric vector is calculated by adding a vector in the circumferential measurement for each measurement point from the gas turbine shake measurement result.

  Next, each vector is plotted on the polar coordinates at a dozen measurement points, and a curved line diagram is completed by plotting points having a large deflection among the polar coordinates in the rotor axis direction.

  Then, the rotor bending unbalance calculation is performed. The rotor bending calculation method will be specifically described below.

  First, a section between the end of the rotor compressor side portion 1a of the rotor 1 and the end of the rotor turbine side portion 1b is divided into small sections in the axial direction, and the axial length of each section (the rotor compressor side portion 1a calculates dWx, and rotor turbine side portion 1b calculates dWy) and weight (Wx).

  Next, the eccentric amount (εx) of the minute section in the previous stage is calculated based on the rotor bending diagram produced from the measured vibration measurement result of the rotor 1, and the minute amount caused by the eccentricity is calculated by multiplying the eccentric amount by the section weight. Calculate the unbalance moment (Mx) of the section section.

  Next, the unbalance moment (Mx) of the minute section is assigned to the nearest correction surface before and after the minute section by the span ratio as follows.

U ₁ = ΣdWx · εx · (L ₁ −x) / L ₁ (1)
U _2R = ΣdWy · εy · (L ₂ −y) / L ₂ (2)
U _2L = ΣdWx · εx · x / L ₁ (3)
U ₃ = ΣdWy · εy · y / L ₂ (4)
The unbalance moment of the next minute section is calculated from one shaft end to the other shaft end, and the unbalance moment at each correction surface is calculated. In this way, it is possible to calculate the imbalance for each correction surface and compare and examine the tendency for each correction surface.

  FIG. 12 is an explanatory diagram showing a process of calculating the rotor bending unbalance based only on the analysis in the low speed balance method according to the second embodiment of the present invention.

  From the results described so far, the following is known regarding the bending of the rotor 1. First, the eccentric directions of the runout measurement points are substantially the same. Next, the eccentricity distribution tends to change substantially linearly with each bearing as the origin and the vicinity of the coupling 4 as the apex.

  From this fact, the eccentric direction on each correction surface is the same, and the distribution of the eccentricity is assumed to be a linear distribution shape with the coupling 4 as the maximum point, and the analysis is performed excluding the actual values such as measurement results. It was.

  First, in FIG. 12, all unbalance moments between the first bearing mounting portion 2 and the unbalance measuring portion 33a are allocated to the first correction surface 11, and the unbalance moment between the second bearing mounting portion 3 and the sixth correction surface 16 is All are allocated to the sixth correction surface 16. About the eccentricity between the 1st correction surface 11 and the 6th correction surface 16, it calculates by the method similar to FIG. 11 (refer Formula (1) thru | or Formula (4)).

That is, the distance from the first correction surface 11 is set as x, and the product of the eccentricity ε and the distance dx in a minute section from x to x + dx is an inverse ratio of the distances to the first correction surface 11 and the sixth correction surface 16. Allocate and integrate it over the distance between the first correction surface 11 and the sixth correction surface 16.

  Finally, the moment ratio is calculated by dividing the calculated allocation moment to the sixth correction surface 16 by the allocation moment of the first correction surface 11. When each distance parameter was input using an actual plant as an example, it was 1.4, which was a result supporting the actual value shown in FIG.

  However, this value varies depending on each distance parameter. In the present embodiment, assuming that the bending form of the rotor 1 is the maximum runout at a portion other than the coupling 4, the moment ratio between the first correction surface 11 and the sixth correction surface 16 is made constant at 1.4. Instead, the plant-specific moment ratio is calculated for each plant by calculation using the equations (5) and (6), and the bending unbalance and rotor blade replacement unbalance of the rotor 1 are calculated based on the moment ratio obtained by the analysis. As a way to separate.

  As described above, in the present embodiment, similar to the first embodiment, the turbine blades are replaced at once, and the blade replacement unbalance and the rotor bending unbalance are separated from the two-surface correction balance result, The correction weight can be appropriately distributed.

  Furthermore, by calculating the rotor bending imbalance, even when the eccentric axial peak position is not in the coupling 4, the imbalance can be separated.

  As a result, it is possible to perform low-speed balance with fewer steps without reducing accuracy, and balance work can be performed in a shorter process than before.

[Other Embodiments]
As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention.

  Moreover, you may combine the characteristic of each embodiment.

  Furthermore, these embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention.

  These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Rotor, 1a ... Rotor compressor side part, 1b ... Rotor turbine side part, 2 ... 1st bearing mounting part, 3 ... 2nd bearing mounting part, 4 ... Coupling, 5 ... First stage turbine blade, 6 2nd stage turbine blade, 7 ... 3rd stage turbine blade, 8 ... 1st bearing, 9 ... 2nd bearing, 11 ... 1st correction surface, 12 ... 2nd correction surface, 13 ... 3rd correction surface, 14 ... Fourth correction surface, 15 ... Fifth correction surface, 16 ... Sixth correction surface, 21 ... First correction surface mounting balance weight, 22 ... Second correction surface mounting balance weight, 23 ... Third correction surface mounting balance weight 24 ... 4th correction surface mounting balance weight, 25 ... 5th correction surface mounting balance weight, 26 ... 6th correction surface mounting balance weight, 31a ... 1st bearing mount, 31b ... 2nd bearing mount, 32 ... low-speed balancer, 33a, 33b ... , Balance balance measurement unit, 34a, 34b ... unbalance calculation unit, 41 ... dial gauge, 42 ... key phaser (reference point), 51 ... unbalance separation / weight calculation unit, 52 ... correction surface weight calculation unit, 53 ... output Display unit, 54 ... database, 55 ... input unit, 100 ... balance evaluation device

Claims (9)

In a turbine having a rotor in which discs are laminated in the axial direction, a low-speed balance method is performed at low speed rotation to regenerate unbalance around the rotation axis of the rotor,
A blade removal step for removing all stages of the turbine blade;
A blade attachment step to install a new turbine blade for each stage;
A first balance measurement step for measuring an unbalance in a low-speed rotation state;
Based on the measurement result in the first balance measurement step, unbalance separation for separating the unbalance into the rotor bending unbalance and the rotor blade replacement unbalance is performed, and the balance weight amount and position to be added to each correction surface are set. An unbalance separation evaluation step;
A first addition step of adding a balance weight to each correction surface based on the result of the unbalance separation evaluation step;
A second balance measuring step for measuring an unbalance in a low-speed rotation state after the first adding step;
After the second balance measurement step, a final addition step of adding balance weights to the correction surfaces at both ends,
A low-speed balance method characterized by comprising: The first balance measurement step includes unbalance measurement at a first measurement point that is a measurement point on the turbine exhaust side and a second measurement point that is a measurement point on the compressor intake side,
The unbalance separation evaluation step includes
The rotor bending unbalance first vector for setting the rotor bending unbalance first vector at the first measurement point on the assumption that all the unbalance measurement results at the second measurement point are unbalanced due to the bending of the rotor. Configuration steps;
The rotor bending unbalance first vector is multiplied by a predetermined magnification obtained based on the moment ratio and angle difference of the rotor bending unbalance at the first measurement point and the second measurement point to the rotor bending unbalance first vector. A rotor bending unbalance second vector setting step for setting a vector;
A rotor bend unbalance total vector setting step for setting a rotor bend unbalance total vector by adding the rotor bend unbalance first vector and the rotor bend unbalance second vector;
A blade replacement unbalance vector separation step of obtaining a blade replacement unbalance vector by subtracting the rotor bending unbalance second vector from the unbalance measurement result of the second measurement point;
A distributing step of distributing each unbalance to each correction surface from the blade replacement unbalance vector and the rotor bending unbalance total vector;
The low-speed balance method according to claim 1, wherein:   The low speed balance method according to claim 2, wherein the moment ratio and the angle difference are calculated based on a rotor bending unbalance analysis.   4. The low speed balance method according to claim 3, wherein the rotor bending unbalance analysis is calculated based on a change to the balance weight added this time, based on the balance weight added last time. A third low-speed rotation step for rotating the rotor at a low speed;
After the third low-speed rotation step, a rotor run-out measurement step for measuring the amount of eccentricity in each direction for each part in the axial direction of the rotor;
Have
4. The rotor bending unbalance is calculated by calculating an eccentric amount and an angle from a result of the rotor deflection measurement step, and integrating a moment due to eccentricity of each axial section. The low-speed balance method described.   The low speed balance method according to claim 5, wherein the rotor shake measurement step is performed before the moving blade removal step.   The correction moment corresponding to the rotor blade exchange imbalance is equally attached to each turbine blade if the value evenly allocated to each turbine blade is equal to or greater than the specified value, and in the priority order if it is less than the specified value. The low-speed balance method according to any one of claims 2 to 6, wherein the low-speed balance method is attached according to the method.   The low-speed balance method according to any one of claims 1 to 7, further comprising a previous weight removing step of removing a balance weight before the moving blade removing step. In a turbine having a rotor in which discs are laminated in the axial direction, a low-speed balance device that performs low-speed rotation to regenerate unbalance around the rotation axis of the rotor,
At least two bearings;
A vibration sensor provided in each of the two bearings;
A low-speed balancer that is coupled to a rotor of a rotating device mounted on the bearing and rotates the rotor at a low speed;
An evaluation device for performing an unbalance evaluation using a signal from the vibration sensor as an input;
With
The evaluation device is
A database in which actual machine data relating to unbalance measurement results at a first measurement point that is a measurement point on the turbine exhaust side and a second measurement point that is a measurement point on the anti-turbine side is accumulated;
A rotor bending unbalance second vector at a second measurement point, a rotor bending unbalance first vector obtained by multiplying the rotor bending unbalance second vector by a predetermined magnification obtained based on the database, and the first measurement. Rotor bending by adding the rotor blade unbalance vector obtained by subtracting the rotor bending unbalance first vector from the point unbalance measurement result, and the rotor bending unbalance first vector and the rotor bending unbalance second vector. An unbalance total vector, and based on this unbalance evaluation result, each unbalance is distributed to each correction surface weight calculation unit for the correction surface,
A low-speed balance device comprising:

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