Blisk vibration detection device

Abstract

In a vibration detection apparatus (1), a plurality of blades (7) formed integrally with the outer periphery of a disk (5) of a blisk (3) are respectively excited by a plurality of excitation signals from progressive waves or regressive waves, the phases of which are sequentially offset in an advancing direction or a delay direction, a laser beam for detecting vibration of the plurality of blades is output, a reflected beam from an object irradiated by the laser beam is received, the optical paths of the output laser beam (LB) and the reflected beam are changed in accordance with a vibration detection position of a blade (7) designated as the irradiation object of the laser beam (LB), and a vibration response to excitation of each blade (7) is detected from the reflected beam and the laser beam (LB) corresponding to each excited blade (7).

Description

[Technical Field]

[0001] The present disclosure relates to a vibration detection device for a blisk. [Background technology]

[0002] For example, the low-pressure and high-pressure compressors of jet engines are provided with rotor blades. Each rotor blade has a disk and a plurality of blades attached to the outer periphery of the disk. If there is variation in mass, stiffness, or natural frequency between the blades of the rotor blade, the rotor blade will vibrate in an unexpected mode due to resonance during rotation, which may shorten the life of the rotor blade.

[0003] Patent Document 1 discloses a technology for suppressing vibrations in modes caused by mistuning of mass, stiffness, or natural frequency of rotating blades configured by fitting the dovetail of the blade to the outer periphery of a disk. The technology proposed in Patent Document 1 proposes arranging blades with different masses, stiffness, or natural frequencies in a deliberate pattern. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-1222 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, rotor blades are sometimes configured with blisks. Blisks are also called integrally bladed rotors (IBRs). In blisks, the blades are formed integrally with the disk. For this reason, with blisks, it is not possible to intentionally position each blade, as in the technology of Patent Document 1. Therefore, when rotor blades are configured with blisks, it is necessary to analyze whether or not the blisk will cause vibrations in unexpected modes during rotation, based on the measurement results of the vibration response that occurs in each blade of an actual blisk during rotation.

[0006] An object of the present disclosure is to provide a blisk vibration detection device that can accurately detect vibration responses occurring in each blade of an actual blisk during rotation. [Means for solving the problem]

[0007] The blisk vibration detection device according to the present disclosure includes a plurality of excitation units that excite a plurality of blades formed integrally on the outer periphery of a blisk disk with a plurality of excitation signals based on progressive waves or backward waves whose phases are sequentially shifted in the advance or delay direction, respectively; a laser vibrometer that outputs laser beams for vibration detection of the plurality of blades and receives reflected beams from an object irradiated with the laser beams; an optical path changing unit that is arranged on the optical path of the laser beams and changes the optical paths of the laser beams and the reflected beams in accordance with the vibration detection position of a blade designated as an object to be irradiated with the laser beams among the plurality of blades; and a controller that detects the vibration response of each of the blades to the excitation from the laser beams and the reflected beams corresponding to each of the blades being excited by the excitation units.

[0008] In the blisk vibration detection device according to the present disclosure, each of the excitation units may change the frequency of the excitation signal to vibrate each of the corresponding blades, and the controller may detect the vibration response for each frequency of the excitation signal.

[0009] In the blisk vibration detection device according to the present disclosure, each of the vibrating units may vibrate each of the corresponding blades at an excitation order that simulates pressure fluctuations that occur in a fluid around the blisk due to rotation of the blisk.

[0010] In the blisk vibration detection device according to the present disclosure, the controller may detect the amplitude and phase of the vibration response, analyze the distribution of the detected amplitude and phase of each of the blades, and detect the number of nodal diameters of the vibration generated in the blisk by the vibration response. [Effects of the Invention]

[0011] According to the present disclosure, it is possible to accurately detect the vibration response occurring in each blade of an actual blisk during rotation. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view showing a vibration detection device for a blisk according to one embodiment. [Figure 2] FIG. 2 is an enlarged perspective view of a laser head, an optical path changing unit, and an imaging unit arranged above the blisk installation portion in FIG. [Figure 3] FIG. 3 is an explanatory diagram of the galvanometer mirror and motor that constitute the optical path changing unit of FIG. [Figure 4] FIG. 4 is an explanatory diagram showing the deviation between the calculated irradiation position of the laser beam and the actual irradiation position on the target plane when the voltage applied to the motor in FIG. 3 is changed linearly. [Figure 5A] FIG. 5A is an explanatory diagram showing the characteristics of the amount of deviation of the actual irradiation point from the calculated irradiation point of the laser beam shown in FIG. 4 in the X-axis direction. [Figure 5B] FIG. 5B is an explanatory diagram showing the characteristic of the amount of deviation of the actual irradiation point from the calculated irradiation point of the laser beam shown in FIG. 4 in the Y-axis direction. [Figure 6] FIG. 6 is a flowchart showing an example of the procedure for adjusting the irradiation location of the laser beam, which is performed prior to detecting the vibration response of each blade of the blisk in the vibration detection device of FIG. [Figure 7] FIG. 7 is a flowchart showing an example of a procedure for detecting vibrations occurring during rotation of a blisk, which is executed in the vibration detection device under the control of the controller of FIG. [Figure 8] FIG. 8 is a diagram showing a ZZENF diagram superimposed on the vibration characteristic diagram of the blisk in FIG. [Figure 9] FIG. 9 is a graph showing the vibration response of the blade detected by the vibration detection unit of the controller in FIG. 1 for each blade of the blisk as a distribution for each frequency of the excitation signal. DETAILED DESCRIPTION OF THE INVENTION

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some exemplary embodiments will be described below with reference to the drawings. Figure 1 is an explanatory diagram showing a vibration detection device 1 for a blisk 3 according to one embodiment.

[0014] The vibration detection device 1 for a blisk 3 of the embodiment shown in Fig. 1 detects the vibration response of a plurality of blades 7 formed integrally on the outer periphery of a disk 5 of the blisk 3. Then, from the detected vibration response of each blade 7, the vibration detection device 1 detects the ratio between the responses of each blade 7 to the vibration of the blisk 3 as an evaluation index for vibrations occurring in the blisk 3 during rotation. Note that the blisk 3 shown in Fig. 1 is simplified for the purpose of explanation, and the number of blades 7 formed on the disk 5 is not limited to the number shown in Fig. 1.

[0015] The vibration detection device 1 includes, for example, an excitation speaker 11, a laser head 13, an optical path changing unit 15, an imaging unit 17, and a controller 19. The blisk 3, the object of which vibrations are to be detected during rotation, is fixed to a blisk installation portion 23 of a test table 21 and installed horizontally, as in the example shown in FIG.

[0016] A plurality of excitation speakers 11 are provided, for example, in one-to-one correspondence with each blade 7 of the blisk 3. Each excitation speaker 11 is disposed, for example, between the blisk 3 installed in the blisk installation section 23 and the test table 21, and faces the ventral surface of each corresponding blade 7 that faces the test table 21.

[0017] Each excitation speaker 11 is activated by an excitation signal of a traveling wave or a backward wave of the same frequency and amplitude. The phase of each excitation signal is sequentially shifted in the leading or lagging direction. Each excitation signal is a traveling wave with a traveling speed or a backward wave with a backward speed that simulates the pressure fluctuations that occur in the fluid around the blisk 3 due to the rotation of the blisk 3.

[0018] The excitation speakers 11, activated by the excitation signal, output sound waves corresponding to the waveform of the excitation signal from the vibration surface (not shown) of the speaker. These sound waves excite the blades 7 of the blisk 3 facing each excitation speaker 11. By exciting each blade 7 with the excitation speaker 11, it is possible to generate a vibration response in each blade 7 that simulates the rotation of the blisk 3. In other words, each excitation speaker 11 functions as a vibration unit that excites each blade 7 facing the excitation speaker 11.

[0019] A support column 25 is erected on the test table 21. The support column 25 supports an arm 27 shown in FIG. 2 so that its position can be adjusted in the up-down and front-rear directions. The tip end of the arm 27 extends forward from the support column 25. A support base 29 is attached to the tip end of the arm 27. The support base 29 is arranged above the blisk installation section 23. The laser head 13, the optical path changing unit 15, and the photography unit 17 are attached to the support base 29.

[0020] The laser head 13 outputs a laser beam LB for vibration detection to be irradiated onto an object and receives a reflected beam (not shown) from the object. The focal length of the laser beam LB output by the laser head 13 can be adjusted according to the length of the optical path of the laser beam LB to the object. The laser head 13 has a laser light source, an optical system, and a photoreceiver. The optical system separates the laser light output by the laser light source into detection light and reference light, combines the detection light reflected by the object with the reference light modulated for vibration direction detection, and receives the combined light at the photoreceiver. The laser head 13 is connected to a vibration detection unit (not shown) of the controller 19, which will be described later.

[0021] The optical path changing unit 15 is disposed on the optical path of the laser beam LB output by the laser head 13. The optical path changing unit 15 changes the optical path of the laser beam LB from the laser head 13 toward the blade 7, which is the irradiation target for vibration detection. In other words, the optical path changing unit 15 functions as an optical path changing section that changes the optical paths of the laser beam LB and a reflected beam (not shown) to match the vibration detection position of the blade 7, which is designated as the irradiation target. The optical path changing unit 15 includes, for example, an X-axis galvanometer mirror 31, an X-axis motor 35, a Y-axis galvanometer mirror 33, and a Y-axis motor 37, as shown in FIG. 3 .

[0022] The X-axis galvanometer mirror 31 reflects the laser beam LB from the laser head 13. The motor 35 rotates the galvanometer mirror 31 to change the optical path of the laser beam LB after reflection by the galvanometer mirror 31 along the X-axis direction. The Y-axis galvanometer mirror 33 reflects the laser beam LB after reflection by the X-axis galvanometer mirror 31. The motor 37 rotates the galvanometer mirror 33 to change the optical path of the laser beam LB after reflection by the galvanometer mirror 33 along the Y-axis direction.

[0023] When one of the galvanometer mirrors 31 and 33 is rotated, the incident angle and the outgoing angle of the laser beam LB with respect to the other mirror change even if the other mirror is not rotated. This change in the incident angle and the outgoing angle causes distortion in the optical path traced by the reflected laser beam when the other mirror is rotated.

[0024] For example, as shown in Fig. 4, motors 35 and 37 of galvanometer mirrors 31 and 33 are driven so that laser beam LB is irradiated onto a calculated irradiation point T where ruled lines drawn at equal intervals along the X and Y axes intersect on a target plane 39. Then, in the example shown in Fig. 4, actual irradiation point S of laser beam LB deviates from the calculated irradiation point T, particularly in the X-axis direction.

[0025] In the example of Figure 4, the deviation of the actual irradiation point S from the calculated irradiation point T in the X-axis direction increases as the coordinate value on the X-axis increases, and increases as the point moves away from the origin in the Y-axis direction. Note that deviation of the actual irradiation point S also occurs in the Y-axis direction. The deviation of the actual irradiation point S has nonlinear characteristics in both the X-axis and Y-axis directions.

[0026] The above-described deviation characteristics can be represented by, for example, a B-spline (Basis spline) surface for each of the X-axis and Y-axis directions. B-spline surfaces 41 and 43 shown in Figures 5A and 5B, respectively, are surfaces that include all points indicating deviation amounts of actual irradiation points S plotted for each calculated irradiation point T of the laser beam LB.

[0027] The correction function for correcting the above-mentioned deviation and making the actual irradiation point S of the laser beam LB coincide with the calculated irradiation point T can be defined by the inverse function of the B-spline surface for each of the X-axis and Y-axis directions. In other words, by correcting the rotation angles of the galvanometer mirrors 31 and 33 corresponding to the calculated irradiation point T using the above-mentioned correction function, the actual laser beam LB can be irradiated onto the calculated irradiation point T.

[0028] As shown in FIG. 1, the photographing unit 17 is disposed above the optical path changing unit 15. For example, a PTZ (Pan Tilt Zoom) camera can be used as the photographing unit 17. A PTZ camera is a 360-degree camera unit that combines a pan head with a swivel function in the X-axis and Y-axis directions with a network camera with a zoom function. The photographing unit 17 photographs, from above the optical path changing unit 15, images for confirming the location of irradiation of the laser beam on the blisk 3 installed in the blisk installation section 23.

[0029] The controller 19 includes, for example, a vibration detection unit that controls the laser head 13, a vibration speaker 11, and a personal computer. The personal computer controls the operations of the optical path changing unit 15 and the photographing unit 17.

[0030] The vibration detection unit cooperates with the laser head 13 to form a non-contact laser vibrometer utilizing the conventionally known Doppler effect. The vibration detection unit controls the output of the laser beam LB from the laser head 13. The vibration detection unit receives an electrical signal corresponding to the amount of light received from the photodetector of the laser head 13, which receives a reflected beam (not shown) of the laser beam LB reflected by a vibrating object. This reflected beam undergoes a Doppler shift corresponding to the vibration velocity of the object. Therefore, the vibration detection unit demodulates the electrical signal input from the laser head 13 to measure the vibration velocity of the object. The vibration detection unit then detects the amplitude of the vibration occurring in the object from the measured vibration velocity and outputs the detection result to a personal computer.

[0031] The personal computer includes, for example, a main body having a CPU, ROM, and RAM, and an input unit and an output unit connected to the main body. When the CPU in the personal computer executes a program stored in the ROM, the controller 19 controls the operations of the vibration speaker 11, the optical path changing unit 15, and the photographing unit 17. The controller 19 also controls the operation of the laser head 13 via the vibration detection unit.

[0032] In this embodiment, the vibration detection unit is configured as hardware that is physically separate from the personal computer. However, the vibration detection unit may be virtually configured on the personal computer by the CPU of the personal computer executing a program. In this case, the controller 19 may be configured as a standalone personal computer that also functions as the vibration detection unit.

[0033] The vibration detection device 1 having the above configuration can detect the vibration response of the blades 7 that occurs during rotation of the blisk 3 and detect the blade-to-blade ratio of the responses of each blade 7. The procedure of the operation performed by the vibration detection device 1 will be described later.

[0034] In addition, when detecting the vibration response of each blade 7 in the vibration detection device 1, prior to that, an adjustment process can be performed on the irradiation point S of each blade 7 where the laser beam LB of the laser head 13 is actually irradiated.

[0035] This adjustment process can be performed individually for each blade 7. The adjustment process for each blade 7 includes, for example, as shown in Fig. 6, a step of correcting the rotation angles of the galvanometer mirrors 31 and 33 (step S1) and a step of fine-tuning the vibration detection points (step S3).

[0036] In step S1, a specific position on each blade 7 of the blisk 3 installed in the blisk installation section 23 is set as a calculated irradiation point T of the laser beam LB. The calculated irradiation point T on each blade 7 can be, for example, an upstream corner in the rotation direction of the blisk 3, on the tip side of the suction surface of the blade 7 that is exposed to the photographing unit 17 when the blisk 3 is installed in the blisk installation section 23. The position of the irradiation point T on each blade 7 of the blisk 3 installed in the blisk installation section 23 is known in advance.

[0037] Then, the rotation angles of the galvanometer mirrors 31 and 33 corresponding to the calculated irradiation point T of each blade 7 are corrected using the correction function described above, and the galvanometer mirrors 31 and 33 are rotated to the corrected rotation angles.

[0038] In step S1, before or after the correction of the rotation angles of the galvanometer mirrors 31 and 33, or in parallel, the laser head 13 outputs a laser beam LB whose focal length is adjusted to the calculated irradiation point T of each blade 7.

[0039] Next, in step S3, the wing 7 irradiated with the laser beam LB after reflection by the galvanometer mirrors 31, 33 at the corrected rotation angle is photographed by the PTZ camera of the photographing unit 17. Then, the image photographed by the PTZ camera is processed by the controller 19 to extract from the photographed image the edge on the tip side of the wing 7 that is closest to the calculated irradiation point T of the laser beam LB and the beam spot of the laser beam LB on the wing 7, i.e., the actual irradiation point S.

[0040] Furthermore, the controller 19 determines whether the laser beam LB is irradiated onto the calculated irradiation point T of the blade 7 by the galvanometer mirrors 31 and 33 at the corrected rotation angle, based on the positional relationship between the extracted edge of the blade 7 and the actual irradiation point S. If the actual irradiation point S of the laser beam LB deviates from the calculated irradiation point T, the controller 19 fine-tunes the vibration detection point of the blade 7. Specifically, the controller 19 fine-tunes the rotation angles of the galvanometer mirrors 31 and 33 so that the laser beam LB is irradiated onto the calculated irradiation point T of the blade 7.

[0041] When the adjustment process of the irradiation point S is completed by the above procedure, the vibration detection device 1 is ready to detect the vibration response of the blade 7 that occurs during rotation of the blisk 3.

[0042] An example of a procedure executed in the vibration detection device 1 to detect the nodal diameter mode of the blisk 3 during rotation will be described with reference to FIG.

[0043] First, in order to simulate the vibrations applied to each blade 7 during rotation of the blisk 3, the controller 19 activates each excitation speaker 11 with an excitation signal (step S11). The excitation signal of each excitation speaker 11 is a traveling wave or a backward wave with the same frequency and amplitude. The controller 19 activates each excitation speaker 11 with an excitation signal of a traveling wave whose phase is sequentially shifted in the leading direction or a backward wave whose phase is sequentially shifted in the lagging direction.

[0044] When each excitation speaker 11 is activated, each corresponding blade 7 of the blisk 3 installed in the blisk installation section 23 is excited by a sound wave according to the waveform of the excitation signal. This excitation generates a vibration response in each blade 7 that simulates the rotation of the blisk 3. The vibration response of each blade 7 contains the same frequency components as the excitation signal used by the controller 19 to activate the corresponding excitation speaker 11.

[0045] Next, the controller 19 controls the vibration detection unit to output the laser beam LB from the laser head 13. The controller 19 also rotates the galvanometer mirrors 31 and 33 of the optical path changing unit 15 by the motors 35 and 37 to a rotation angle corresponding to the calculated irradiation point T on the blade 7 whose vibration response is to be detected (step S13).

[0046] As a result, the laser beam LB from the laser head 13 is irradiated onto the irradiation point T of the blade 7 by the optical path changing unit 15. The reflected beam from the irradiation point T is received by the laser head 13 via the optical path changing unit 15.

[0047] Next, the controller 19 causes the vibration detection unit to detect the speed of vibration generated in the target wing 7 as a vibration response based on the laser beam LB output by the laser head 13 and the received reflected beam (step S15).

[0048] Then, the controller 19 repeats the procedures of steps S13 and S15 (NO in step S17) until the vibration detection unit detects vibration responses for all of the blades 7 of the blisk 3. During this repetition, the order of the blades 7 targeted in the procedures of steps S13 and S15 may be the order in which they are arranged in the rotation direction of the blisk 3, or may be any other order, including random.

[0049] Furthermore, the controller 19 may, as necessary, execute the procedures of step S13 and step S15 multiple times for the same wing 7. When executing the procedures multiple times, the controller 19 may execute the procedures of step S13 and step S15 consecutively for each execution, or may execute the procedures of step S13 and step S15 after executing the procedures of step S13 and step S15 for another wing 7.

[0050] When each blade 7 of the blisk 3 is excited at its natural frequency, it resonates with a large amplitude. Therefore, the controller 19 needs to detect the vibration response when each blade 7 is excited at its natural frequency. However, the natural frequency of each blade 7 is usually unknown. Therefore, the controller 19 repeatedly executes all the steps in Fig. 7 while sequentially changing the frequency of the excitation signal.

[0051] When the vibration detection unit has detected vibration responses for all blades 7 (YES in step S17), the controller 19 determines whether or not the vibration responses of the blades 7 have been detected by setting the frequency of the vibration signal to all frequencies from the upper limit to the lower limit of the selection range (step S19). If there are any frequencies that have not been set (NO in step S19), the controller 19 resets the frequency of the vibration signal (step S21) and then returns to step S11. The controller 19 repeatedly executes the procedures of steps S13 and S15, for example, as follows.

[0052] The graph in Figure 8 shows a ZZENF diagram (zig-zag shaped excitation line in the nodal diameters versus frequency diagram) superimposed on the vibration characteristic diagram of the blisk 3. The vibration characteristic diagram of the blisk 3 shows the relationship between the vibration frequency of the blisk 3 and the nodal diameter number of vibrations occurring in the disk 5 and each blade 7. The graphs 1F to 3F in the diagram show the vibration frequency and nodal diameter number when each blade 7 vibrates in the first to third bending (1F to 3F) modes. The graph 1T in the diagram shows the vibration frequency and nodal diameter number when each blade 7 vibrates in the first torsional (1T) mode. The zigzag line in the ZZENF diagram shows the excitation frequency at a certain rotation speed.

[0053] In the graph of Figure 8, it is possible to confirm whether the vibration in each mode is due to a progressive wave or a backward wave by looking at the slope of the zigzag line of the ZZENF diagram that intersects with the graph of the vibration characteristics diagram.

[0054] By using a Campbell diagram, which shows the resonant rotation range with frequency on the vertical axis, rotation speed on the horizontal axis, and rotation order on the diagonal axis, in conjunction with the graph in Figure 8, it is possible to identify the modes that should be investigated in testing in the design.

[0055] Note that the natural frequencies plotted in the vibration characteristics diagram of the blisk 3 in Fig. 8 are values ​​after centrifugal force correction and temperature correction according to the actual machine state. Therefore, in tests conducted in a stationary state at room temperature, it is necessary to confirm the frequency of the corresponding mode before the test.

[0056] First, in the example shown in Fig. 8, the controller 19 converts the frequency at which the nodal diameter number becomes a first specific number in the 1F mode vibration of each blade 7 into a frequency at room temperature and in a stationary state, and sweep-vibrates each blade 7 with a traveling wave in a frequency range in which a resonance curve can be obtained. At this time, the phase difference of the vibration signal for each blade 7 is set to a phase difference corresponding to the first specific number of nodal diameters. In other words, the nodal diameter number is fixed.

[0057] Next, the controller 19 converts the frequency at which the nodal diameter number becomes a second specific number in the 1T mode vibration of each blade 7 into a frequency at room temperature and in a stationary state, and sweeps and vibrates each blade 7 with a backward wave in a frequency range in which a resonance curve can be obtained.

[0058] The phase difference of the vibration signals of each blade 7 is set to a phase difference according to the number of nodal diameters.

[0059] By repeating sweep excitation using forward and backward waves in such a mode with a number of nodal diameters that may be excited, the controller 19 repeatedly executes the procedures of steps S13 and S15 in FIG. 7 while sequentially changing the frequency of the excitation signal.

[0060] When the frequencies of the vibration signals have been set to all frequencies (YES in step S19), the controller 19 extracts the detected peak amplitudes of the vibration responses of each blade 7 (step S23). Then, the controller 19 detects the blade-to-blade ratio of the responses of each blade 7 to the vibrations occurring in the rotating blisk 3 from the extracted peak amplitudes of each blade 7 (step S25).

[0061] Here, the vibration response of each blade 7 of the blisk 3 detected by the vibration detection unit of the controller 19 will be described with reference to Fig. 9. The graph in Fig. 9 shows the vibration response of each blade 7 detected by the vibration detection unit as a distribution for each frequency of the excitation signal.

[0062] In the graph of Fig. 9, the width direction axis indicates the vibration frequency of the blades 7, the depth direction axis indicates the arrangement number of each blade 7 in the rotation direction of the blisk 3, and the height direction axis indicates the peak amplitude of the blades 7. Fig. 9 shows the distribution of the amplitude of each blade 7 only for some vibration frequency bands.

[0063] As shown in Figure 9, the amplitude of the vibration response detected for each blade 7 peaks at a specific vibration frequency for each blade 7. The vibration frequency at which the amplitude peaks is considered to be the resonant frequency of each blade 7. In other words, there is variation in the natural frequency of each blade 7. There is also variation in the amplitude peaks of each blade 7.

[0064] The vibration response of each blade 7 is a progressive wave or a backward wave whose phase is sequentially shifted in the leading or lagging direction, just like the excitation signal from the excitation speaker 11 that vibrates each blade 7 while the blisk 3 is stopped, simulating the rotation of the blisk 3. At this time, the vibration mode generated in each blade 7 is a mode of the nodal diameter number according to the excitation order applied to the blisk 3 of the stationary system.

[0065] It should be noted that the amplitude peaks in the vibration response of each blade 7 vary from blade to blade even if the vibration frequency is the same. The controller 19 analyzes the vibration responses of the blades 7 detected by the vibration detection units over the entire circumference of the blisk 3, and compares the vibration peaks of each blade 7 at each vibration frequency between the blades 7. The vibration and phase of each blade 7 can be measured using, for example, a lock-in amplifier.

[0066] With the above, the controller 19 completes a series of procedures for detecting the blade-to-blade ratio of the response of each blade 7 to the excitation of the blisk 3. As is clear from the above explanation, the controller 19 functions as a response detection unit that detects the vibration response of each blade 7 to the excitation from the laser beam LB and the reflected beam (not shown) corresponding to each blade 7 during excitation by each excitation speaker 11. The controller 19 also functions as a nodal diameter number detection unit that detects the nodal diameter number of the vibration generated in the blisk 3 in response to the excitation of each blade 7.

[0067] As described above, in the vibration detection device 1 of this embodiment, the excitation speakers 11 are excited by excitation signals of progressive or backward waves of the same frequency and amplitude, with the phases sequentially shifted in the leading or lagging direction. Then, a vibration response simulating the rotation of the blisk 3 is generated in each blade 7 of the blisk 3 facing each excitation speaker 11.

[0068] By changing the optical path using the optical path changing unit 15, the laser beam LB from the laser head 13 is irradiated onto each blade 7 in sequence, and the reflected beam from each blade 7 is received by the laser head 13. Then, from the Doppler shift amount of the reflected beam relative to the laser beam LB irradiated onto each blade 7, the controller 19 detects the vibration velocity and amplitude of each blade 7, and further detects the inter-blade ratio of the response of each blade 7.

[0069] Therefore, a vibration response simulating the rotating blisk 3 is generated in each blade 7, the vibration response is detected by irradiation with the laser beam LB, and the blade-to-blade ratio of the response of each blade 7 to the vibration generated in the rotating blisk 3 is detected, thereby making it possible to evaluate the vibration of the blisk 3.

[0070] In this embodiment, it is assumed that the natural frequency of each blade 7 is unknown, and the frequency of the excitation signal used to activate the excitation speaker 11 is changed sequentially. However, if the natural frequency of each blade 7 is known, the excitation speaker 11 corresponding to each blade 7 may be activated with an excitation signal having a resonant frequency corresponding to the natural frequency of each blade 7 when detecting the vibration response of each blade 7. In this case, the configuration for changing the frequency of the excitation signal can be omitted.

[0071] The present disclosure may be utilized in a variety of articles where blisks are used, not just low or high pressure compressors.

[0072] Although several embodiments have been described above, the embodiments can be modified or varied based on the above disclosure. All components of the above embodiments and all features described in the claims may be individually extracted and combined, unless they contradict each other.

[0073] The entire contents of Patent Application No. 2021-157576 (filing date: September 28, 2021) are incorporated herein by reference. [Explanation of symbols]

[0074] 1. Vibration detection device 3. Brisket 5 discs 7 wings 11. Excitation speaker (excitation part) 15 Optical path changing unit (optical path changing section) 19 Controller (response detection unit, nodal diameter number detection unit) LB laser beam

Claims

1. a plurality of excitation units that respectively excite a plurality of blades formed integrally on the outer periphery of the blisk disk with a plurality of excitation signals of progressive waves or backward waves whose phases are sequentially shifted in the leading direction or the lagging direction by a phase difference corresponding to a fixed number of nodal diameters; a laser vibrometer that outputs a laser beam for detecting vibration of the plurality of blades and receives a reflected beam from an object irradiated with the laser beam; an optical path changing unit that is disposed on the optical path of the laser beam and changes the optical paths of the laser beam and the reflected beam in accordance with a vibration detection position of a blade designated as an irradiation target of the laser beam among the plurality of blades; a controller for detecting a vibration response of each of the blades to the excitation from the laser beam and the reflected beam corresponding to each of the blades during excitation by each of the excitation units; The controller detects the amplitude and phase of the vibration response, analyzes the detected distribution of the amplitude and phase of each of the blades, detects the number of nodal diameters of vibration generated in the blisk by the vibration response, and evaluates the vibration of the blisk. Blisk vibration detection device.

2. each of the vibration units changes the frequency of the vibration signal to vibrate each of the corresponding blades; The controller detects the vibration response for each frequency of the vibration signal.

2. The vibration detection device for a blisk according to claim 1.

3. Each of the vibration excitation units excites each of the corresponding blades at an excitation order that simulates pressure fluctuations that occur in a fluid around the blisk due to rotation of the blisk.

2. The vibration detection device for a blisk according to claim 1.

4. Each of the vibration excitation units excites each of the corresponding blades at an excitation order that simulates pressure fluctuations that occur in a fluid around the blisk due to rotation of the blisk.

3. The vibration detection device for a blisk according to claim 2.

5. The plurality of vibration units are a plurality of speakers that output sound waves corresponding to waveforms of the plurality of vibration signals. The vibration detection device for a blisk according to any one of claims 1 to 4.

6. The laser vibrometer is a laser vibrometer that utilizes the Doppler effect. The vibration detection device for a blisk according to any one of claims 1 to 4.

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