Non-contact blade vibration test test bed

Abstract

The application belongs to the field of mechanical parts vibration monitoring, and proposes a non-contact blade vibration test test bed. High-pressure airflow or magnet is used as excitation load to synchronously or asynchronously excite the blade, the blade tip distance can be freely adjusted, and the non-contact test of the blade vibration condition is realized through the optical fiber type sensor. Specifically, the motor drives the blade to rotate or the magnet sleeved on the bolt to realize synchronous excitation of the blade, the motor drives the nozzle to rotate, the nozzle sprays high-speed gas to realize synchronous excitation or asynchronous excitation of the blade, and the position of the rubbing block can be adjusted to realize the rubbing experiment of the blade. The device can conveniently realize synchronous excitation and asynchronous excitation of the blade disc device, and provide strong support for vibration characteristic test research and blade rubbing experiment research of the blade disc structure, and is convenient for vibration test of the aero-engine whole blade disc.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of mechanical component vibration monitoring, and particularly relates to a non-contact blade vibration test test bed. BACKGROUND

[0002] Blade disc is one of the key components of an aero-engine. During the operation of the aero-engine, the blades in the compressor disc structure are excited by high-pressure airflow and other external loads when rotating at high speed, so that the blades vibrate. Long-term external excitation can cause high-cycle fatigue, damage the blades, and even cause the blades to break, leading to major accidents. At the same time, in order to reduce the compressor tip flow loss as much as possible and improve the performance of the compressor, it is hoped that the tip clearance is as small as possible. However, the smaller the tip clearance, the greater the risk of collision between the high-speed rotating blades and the inner wall of the casing, which may lead to an increase in the rotor-stator clearance, bearing wear, blade breakage and other mechanical failures, thereby reducing the safety and reliability of the engine and endangering aviation safety. Therefore, the vibration characteristics of the blades need to be tested and the blades need to be subjected to a rubbing experiment. In the test and research of the vibration characteristics of the blades, due to the long test period and high test cost of the real running aero-engine, and the fact that the contact type blade measurement changes the vibration characteristics of the blades, an offline simulation method is now used to simulate the resonance of the blades caused by external excitation during the operation of the aero-engine, and the non-contact vibration test of the blades is carried out. In order to better study the vibration of the blades during the operation of the aero-engine, a multifunctional, adjustable tip distance, low-cost non-contact blade vibration simulation test bed is designed, which is of great significance for the test and research of the vibration characteristics of the blades.

[0003] In the aspect of blade non-contact vibration test experiment, Yang Bin, a Chinese scholar, reported a non-contact blade vibration test system in the literature "Rotating blade vibration monitoring test and parameter identification". The blade vibration test device adopts a fixed nitrogen nozzle fixed on one side of the casing to excite the rotating blade by airflow, and four eddy current sensors are installed on the casing of the outer circle of the blade to non-contact measure the blade vibration. The eddy current sensor used in the test device has low resolution, and the number of sensors arranged is small, the sampling rate of blade vibration displacement is low, and it is greatly affected by the rotating speed. At the same time, the fixed nozzle is used for airflow excitation in the device, the excitation mode is single and can only be synchronous excitation. Xu Hai-long, a Chinese scholar, reported a blade online vibration test platform using pneumatic excitation and a blade online vibration test platform using magnet excitation in the literature "Key technology research on blade end timing non-contact online detection of rotating blade cracks". Two experimental platforms are designed to realize two different excitation modes, and the experimental platform has a long construction period and high cost. The invention patent "Rotating blade excitation system and rotating blade vibration test system" (CN201810222468.3) of Beijing University of Chemical Technology reports a rotating blade vibration test system using pneumatic excitation. Two eddy current sensors are arranged in the test device, the sensor position is fixed, the space variability is small, and the excitation mode for the blade is single. SUMMARY

[0004] To solve the above problems, the present application provides a non-contact blade vibration test platform, which uses high-pressure airflow or a magnet as an excitation load to excite the blade synchronously or asynchronously, can freely adjust the blade tip distance, and realizes non-contact test of blade vibration through an optical fiber sensor. The test platform has the advantages of realizing high-pressure airflow and magnet external excitation, freely adjusting the sensor installation position along the circumference, freely adjusting the blade tip distance, realizing synchronous and asynchronous excitation, and adjusting the blade disc along the axial direction, can realize various excitation forms, and freely adjust the blade tip gap.

[0005] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0006] A non-contact blade vibration test platform mainly consists of a platform base assembly 7 and a power assembly 1, a connecting assembly 2, a bearing assembly 3, a vibration test assembly 4, a gas excitation application assembly 5, a driving and control assembly 6 connected in sequence.

[0007] The power assembly 1 is mainly composed of the motor 8 and the motor support 21. The connecting assembly 2 is mainly composed of the fixing bolt 23, the shaft sleeve 24, the pin 25 and the diaphragm 26. The bearing assembly 3 is mainly composed of the bearing seat 11, the bearing seat support 20, the sealing ring 27, the bearing end cover 28, the screw 29 and the angular contact ball bearing 30. The vibration test component 4 is mainly composed of the sensor mounting block 12, the test tool support 19, the expansion sleeve 31, the test support 32, the blade disc 33, the fixing bolts a 34 and 39, the rubbing block, the bolt a 41 and the magnetic block 42. The gas excitation applying assembly 5 is mainly composed of the gas nozzle 13, the gas nozzle support 14 and the gas excitation tool support 18. The driving and control assembly 6 is mainly composed of the stepping motor 15, the stepping motor driving board 16 and the stepping motor speed regulation board 17. The platform base assembly 7 is mainly composed of the lifting lugs 40 and 22 and the mounting bottom plate.

[0008] The motor 8 in the power assembly 1 is connected with the main shaft 10 through the coupling 9 at one end. The main shaft 10 penetrates the bearing assembly 3 and the vibration test assembly 4. The bearing assembly 3 is used for supporting the rotating movement of the main shaft 10. The vibration test component 4 includes the sensor mounting block 12, the test tool support 19, the expansion sleeve 31, the test support 32, the blade disc 33, the rubbing block 39, the bolt a 41 and the magnetic block 42. The test support 32 is in the shape of a ring and is fixed to the mounting bottom plate 22 through the test tool support 19. The expansion sleeve 31 is sleeved on the main shaft 10. The blade disc 33 is fixed between the expansion sleeve 31 and the inner ring of the test support 32. The test support 32 is provided with radial through holes for mounting the rubbing block 39. One end of the rubbing block 39 is in contact with the blade end of the blade disc 33. The clearance distance of the blade end is changed by adjusting the radial position of the rubbing block 39 to complete the rubbing experiment. The sensor mounting block 12 is mounted on the outer ring of the test support 32 in the axial position and is used for connecting the optical fiber sensor to test the vibration of the blade. A plurality of threaded holes 38 are distributed circumferentially on the test support 32. The bolt a 41 with the magnetic block 42 is mounted on the threaded hole 38 and is used for synchronously exciting the blade installed on the rotating blade disc 33.

[0009] The gas excitation applying assembly 5 includes the gas nozzle 13, the gas nozzle support 14 and the gas excitation tool support 18. The gas nozzle support 14 is in the shape of L. One side of the gas nozzle support 14 is mounted on the gas excitation tool support 18. The other side of the gas nozzle support 14 is mounted with the gas nozzle 13. The gas nozzle 13 is connected with the stepping motor 15 of the driving and control assembly 6. The gas nozzle 13 applies gas excitation to the blade disc 33. The gas nozzle 13 is stationary. The motor 8 drives the blade disc 33 to rotate to realize the synchronous excitation of the blades on the blade disc 33. When the motor 8 drives the blade disc 33 to rotate and the stepping motor 15 drives the gas nozzle 13 to rotate and the rotating speeds of the two meet the requirements, the rotating gas is sprayed to realize the asynchronous excitation of the blades on the blade disc 33. The frequency of the rotation of the blade disc 33 and the frequency of the rotation of the gas nozzle 13 are adjusted by the following formula to realize the synchronous excitation or the asynchronous excitation.

[0010]

[0011] wherein, EO is the shaft frequency multiple, (+: counter-rotation; -: co-rotation)

[0012] wherein, f 固有频率 is the natural frequency of the blade installed on the disk 33, f 轴频 is the frequency of the disk 33 rotation, f 喷嘴转频 is the frequency of the gas nozzle 13 rotation.

[0013] The sensor mounting block 12 is provided with seven blocks.

[0014] The power assembly 1 is used to provide power for the disk 33 rotation. The connecting assembly 2 is used to connect the motor 8 and the main shaft 10 to transmit the rotation movement and power. The bearing assembly 3 is used to support the rotation movement of the main shaft 10. The vibration test assembly 4 is used to test the vibration of the blade during the disk 33 rotation. The gas excitation application assembly 5 applies high-pressure gas excitation to the blade on the disk 33 through the gas nozzle 13. The driving and control assembly 6 is used to provide rotation power and control the speed for the gas excitation application assembly 5. The platform base assembly 7 is used to fix the gas excitation tool support 18, the test tool support 19, the bearing seat support 20, and the motor support 21. The bearing seat 11 serves as the outer support of the angular contact ball bearing 30. The sensor mounting block 12 can be fixed at any position around the test support 32 through the threaded hole a36 by screwing in the set screw, and the optical fiber sensor is arranged through the through hole 35 on the sensor mounting block 12. The step motor driving board 16 and the step motor speed regulating board 17 drive and control the rotation movement of the gas nozzle 13.

[0015] The fixing bolt 23 is connected to the shaft of the motor 8 through the shaft sleeve 24. The pin 25 fastens the diaphragm 26 on the shaft sleeve 24. The sealing ring 27 is used to isolate the oil and protect the angular contact ball bearing 30. The bearing end cover 28 is connected with the bearing seat 11 through the screw 29 to fix the angular contact ball bearing 30.

[0016] The expansion sleeve 31 realizes the keyless connection of the disk 33 and the main shaft 10 through the bolt 37. The test support 32 is fixed through the fixing bolt a34.

[0017] The lifting lug 40 is connected with the installation base plate 22 to facilitate the movement of the installation base plate 22 under stress.

[0018] The beneficial effects of the present application are: the non-contact blade vibration test test bench designed by the present application can make the blade produce synchronous or asynchronous excitation through magnetic excitation, static pneumatic excitation and rotating pneumatic excitation, the vibration of the blade is monitored through the installation of multiple optical fiber sensors, the position and number of the optical fiber sensors and the magnet are adjustable, the position of the blade disc can be adjusted along the axial direction, and the rub-impact experiment can be completed by adjusting the blade tip distance. The device can be conveniently used for vibration test of the aero-engine blisk, and provides strong support for the vibration characteristic test research of the blisk structure. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a schematic view of a non-contact blade vibration test test bench;

[0020] Figure 2 is a sectional view of a non-contact blade vibration test test bench;

[0021] Figure 3 is a schematic view of a connecting assembly;

[0022] Figure 4 is a schematic view of a bearing assembly;

[0023] Figure 5 is a schematic view of a vibration test assembly;

[0024] Figure 6 is a sectional view of a part of a vibration test assembly;

[0025] Figure 7 is a schematic view of a platform base assembly;

[0026] Figure 8 is a local sectional view of a magnet installation area.

[0027] In the drawings: 1-power assembly; 2-connecting assembly; 3-bearing assembly; 4-vibration test assembly; 5-gas excitation application assembly; 6-driving and control assembly; 7-platform base assembly; 8-motor; 9-coupling; 10-main shaft; 11-bearing seat; 12-sensor installation block; 13-gas nozzle; 14-gas nozzle support; 15-stepping motor; 16-stepping motor driving plate; 17-stepping motor speed regulating plate; 18-gas excitation tool support; 19-test tool support; 20-bearing seat support; 21-motor support; 22-installation base; 23-fixing bolt; 24-shaft sleeve; 25-pin; 26-diaphragm; 27-sealing ring; 28-bearing end cover; 29-screw; 30-angular contact ball bearing; 31-expanding sleeve; 32-test support; 33-blade disc; 34-fixing bolt a; 35-through hole; 36-threaded hole a; 37-bolt; 38-threaded hole; 39-rubbing block; 40-lifting lug; 41-bolt a; 42-magnetic block. DETAILED DESCRIPTION

[0028] Embodiments of the present application are described below in detail, examples of which are shown in the drawings, in which the same reference numbers represent the same parts. The embodiments described below by reference to the drawings are exemplary only, and are used to explain the present application, and cannot be construed as limiting the present application.

[0029] The non-contact blade vibration test test bench comprises a gas excitation applying device 5, a motor 8, a shaft coupling 9, a main shaft 10, a bearing seat 11, a sensor mounting block 12, a stepping motor 15, a stepping motor drive board 16, a stepping motor speed regulation board 17, a gas excitation tool support 18, a test tool support 19, a bearing seat support 20, a motor support 21, a mounting base 22, a sealing ring 27, a bearing end cover 28, a screw 29, an angular contact ball bearing 30, an expansion sleeve 31, a test support 32, a bladed disc 33, a fixing bolt a 34, a bolt 37, a rubbing block 39, bolts a 41, 42 magnetic blocks and the like.

[0030] Working process: After the motor 8 is started and runs, the main shaft 10 is driven to rotate through the shaft coupling 9. The main shaft 10 and the bladed disc 33 are tightly coupled through the expansion sleeve 31. The bladed disc 33 rotates under the driving of the main shaft 10. Then the gas excitation applying device 5 sprays high-pressure gas on the blades on the bladed disc 33 to aerodynamically excite them, so that the blades are synchronously excited. If the stepping motor 15 is driven to rotate by the stepping motor drive board 16 to drive the gas excitation applying device 5 to rotate, rotary aerodynamic excitation can be realized, and the blades are asynchronously excited. During the operation of the stepping motor 15, the speed of the stepping motor 15 can be adjusted through the stepping motor speed regulation board 17. In addition to the aerodynamic excitation mode as described above, the non-contact blade vibration test test bench can also apply magnetic excitation to make the blades on the bladed disc 33 synchronously excited. A plurality of threaded holes 38 are distributed circumferentially on the test support 32. The magnetic block 42 is sleeved on the bolt a 41, passes through the threaded hole 38, and is fixed on the test support 32, so as to realize magnetic excitation of the bladed disc 33. By adjusting the radial position of the rubbing block 39 to change the tip distance, the blades of the bladed disc 33 are in contact with the rubbing block 39 to study the mechanism and influencing factors of rubbing. A plurality of sensor mounting blocks 12 are distributed circumferentially on the test support 32. The sensor mounting blocks 12 are fixed on the test support 32 through the threaded hole a 36 matched with the set screw. The optical fiber sensor is inserted through the through hole 35 on the sensor mounting block 12. After the bladed disc 33 is excited by one of the magnetic excitation, static aerodynamic excitation or rotary aerodynamic excitation, the vibration of the blades on the bladed disc 33 is monitored and tested by a plurality of optical fiber sensors.

[0031] The gas nozzle 13 applies gas excitation to the blade disc 33 to realize synchronous excitation of the blades on the blade disc 33. In synchronous vibration, the gas nozzle 13 is stationary, and the motor 8 drives the blade disc 33 to rotate at a certain speed. The rotating speed of the blade disc 33 is calculated as follows: assuming that (1) the first-order bending mode frequency of the blade is 450 Hz, and (2) the number of the gas nozzles 13 is 10. In order to excite the first-order bending vibration of the blade, the rotating frequency of the blade disc 33 should be 450 / 10=45 Hz; that is, the rotating speed of the blade disc 33 relative to the gas nozzle 13 is 45*60=2700 r / min.

[0032] The stepping motor 15 drives the gas nozzle 13 to rotate, and the rotating gas jet realizes asynchronous excitation of the blades on the blade disc 33. In asynchronous vibration, the blade disc 33 and the gas nozzle 13 rotate at certain speeds, respectively. The rotating speeds of the blade disc 33 and the gas nozzle 13 are calculated as follows: assuming that (1) the first-order bending mode frequency of the blade is 450 Hz, and (2) the number of the nozzles is 10. In order to ensure asynchronous excitation, it is assumed that the frequency multiplication value is 10.5 (non-integer). The relative rotating frequency of the blade disc 33 relative to the gas nozzle 13 should be 450 / 10.5=42.857 Hz; assuming that the rotating frequency of the blade disc 33 is 45 Hz, the rotating frequency of the gas nozzle 13 should be 45-42.857=2.143 Hz. That is, the rotating speed of the gas nozzle 13 should be 2.143*60=128.57 r / min. When the rotating frequency of the blade disc 33 is less than 42.857 Hz, the gas nozzle 13 should rotate in the opposite direction, and the rotating frequency of the gas nozzle 13 increases with the decrease of the rotating frequency of the blade disc 33. When the rotating frequency of the blade disc 33 is greater than 42.857 Hz, the gas nozzle 13 should rotate in the same direction, and the rotating frequency of the gas nozzle 13 increases with the increase of the rotating frequency of the blade disc 33.

Claims

1. A non-contact blade vibration testing rig, characterized in that, The non-contact blade vibration test bench is mainly composed of a platform base assembly (7) and a power assembly (1), a connection assembly (2), a bearing assembly (3), a vibration test assembly (4), a gas excitation application assembly (5), and a drive and control assembly (6) connected in sequence. One end of the motor (8) in the power assembly (1) is connected to the main shaft (10) via a coupling (9); the main shaft (10) passes through the bearing assembly (3) and the vibration test assembly (4); the bearing assembly (3) is used to support the rotational movement of the main shaft (10); the vibration test component (4) includes a sensor mounting block (12), a test fixture bracket (19), a tightening sleeve (31), a test bracket (32), an impeller (33), a rubbing block (39), a bolt a (41), and a magnetic block (42); the test bracket (32) is annular and is fixed to the mounting base plate (22) via the test fixture bracket (19); the tightening sleeve (31) is fitted onto the main shaft (10), and the impeller (33) Fixed between the expansion sleeve (31) and the inner ring of the test bracket (32); the test bracket (32) is provided with a radial through hole for installing a rubbing block (39). One end of the rubbing block (39) contacts the blade end of the blade disk (33). The gap distance at the blade end is changed by adjusting the radial position of the rubbing block (39); a sensor mounting block (12) is installed on the outer ring of the test bracket (32) in the axial position for connecting the fiber optic sensor to test the blade vibration; several threaded holes (38) are distributed circumferentially on the test bracket (32). Bolts a (41) with magnets (42) are installed on the threaded holes (38) for synchronous excitation of the blades installed on the rotating blade disk (33); The gas excitation application component (5) includes a gas nozzle (13), a gas nozzle support (14), and a gas excitation tooling bracket (18). The gas nozzle support (14) is L-shaped, with one side mounted on the gas excitation tooling bracket (18) and the other side mounted on the gas nozzle (13). The gas nozzle (13) is connected to the stepper motor (15) of the drive and control component (6). The gas nozzle (13) applies gas excitation to the impeller (33). When the gas nozzle (13) is stationary, the motor (8) drives the impeller (33) to rotate, thereby achieving synchronous excitation of the blades on the impeller (33). When the motor (8) drives the impeller (33) to rotate and the stepper motor (15) drives the gas nozzle (13) to rotate, and both rotation speeds meet the requirements, the rotating gas is ejected to achieve asynchronous excitation of the blades on the impeller (33). Synchronous or asynchronous excitation is achieved by adjusting the rotation frequency of the impeller (33) and the rotation frequency of the gas nozzle (13) using the following formula. Where EO is the axis frequency multiple, (+: rotation in the opposite direction; -: rotation in the same direction) Among them, f 固有频率 f is the natural frequency of the blades mounted on the bladed disk (33). 轴频 f is the frequency of rotation of the bladed disk (33). 喷嘴转频 The frequency of rotation of the gas nozzle (13).

2. The non-contact blade vibration testing rig according to claim 1, characterized in that, The sensor mounting block (12) consists of seven blocks.

Images