Damage detection system of rotating machinery blade based on vibration

Abstract

The utility model relates to a vibration-based rotary machinery blade damage detection system, which comprises a blade clamping device and a signal detection device, the blade clamping device comprises a blade clamp, a mortise chuck, a driving device and a support table, the blade clamp is a clamping body formed by oppositely buckling a fixed half body and a movable half body, the fixed half body is provided with a sliding seat, and the movable half body is provided with a sliding groove. The movable half body is slidably connected to the sliding seat, the fixed half body is fixedly connected to one side of the supporting table, the movable half body is connected with the driving device, and the driving device is connected with the other side of the supporting table; the mortise chuck is composed of two chuck half bodies, one chuck half body is fixed to the fixed half body, the other chuck half body is fixed to the movable half body, and a mortise formed after the two chuck half bodies are buckled is matched with a tenon at the root of a blade to be detected. The signal detection device comprises a data acquisition instrument, a computer, an exciting force hammer and a three-axis modal acceleration sensor. The device is used for detecting the damage of the rotating mechanical blade, and the accuracy of detection data is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of rotating machinery blade detection, specifically relates to a kind of damage detection system of rotating machinery blade based on vibration. BACKGROUND

[0002] Impeller rotating machinery refers to the turbine, flue gas turbine, water turbine and the working machine driven by steam turbine, flue gas turbine, water turbine and the turbine type fluid power machinery of composition. Blade is an important component of rotating machinery, and its working environment is relatively bad, usually under extreme conditions such as high speed, high temperature and high pressure. In addition, the blade excitation force generated by mechanical transmission, airflow, rotating stall can also cause cracks in rotating blades, breakage and other failures, and ultimately failure, thereby directly affecting the safety and economy of the whole unit. Taking steam turbine as an example, according to statistics, blade failure accounts for about 40% of steam turbine accidents, and blade maintenance cost accounts for about 50.5% of steam turbine maintenance cost, most of which is due to blade vibration fatigue fracture.

[0003] The current online monitoring technology provides a possibility for blade health state identification, but it only considers whether the blade is damaged under operating conditions, and the specific damaged blade still needs to be determined by traditional non-destructive testing technologies such as penetration detection and ultrasonic detection. However, the penetration detection method is effective for blade surface cracks, but it cannot detect internal defects, torsional deformation, installation quality and other problems; ultrasonic detection method cannot detect blades with coating. As can be seen, if the blade surface crack damage, internal crack defect, blade torsional deformation and blade installation quality and other problems cannot be effectively detected, it will bring major hidden dangers to enterprise safety production. Therefore, it is of great significance to develop an effective and convenient blade damage detection technology.

[0004] Modal frequency and modal shape are important structural dynamic characteristic parameters for structural damage detection. Among them, modal frequency can effectively represent the stiffness and mass information of blade structure, and once it deviates from the normal value, it can indicate that the blade is damaged. Therefore, the structural damage detection method based on vibration modal analysis provides an effective means for blade damage detection. SUMMARY

[0005] The utility model aims at providing a kind of damage detection system of rotating machinery blade based on vibration, and this kind of damage detection system of rotating machinery blade based on vibration is used to solve the problem of impeller rotating machinery into blade damage detection.

[0006] The utility model discloses a technical scheme that solves its technical problem is as follows: this kind of damage detection system of rotating machinery blade based on vibration includes blade clamping device, signal detection device, and blade clamping device includes blade clamp, mortise chuck, drive arrangement, bolster, and the blade clamp is formed by the clamping body of open upper end of fixed half and mobile half buckling, and fixed half has sliding seat, and mobile half is slidably connected on the sliding seat, and fixed half is fixedly connected on one side of bolster, and mobile half is connected drive arrangement, and drive arrangement is connected with the other side of bolster through trunnion support, and mortise chuck is formed by two chuck halves, and chuck half is fixed on fixed half, and the other chuck half is fixed on mobile half, and the mortise formed after two chuck halves buckling is matched with the tenon of the root of blade to be measured, and signal detection device includes data acquisition instrument, computer, excitation force hammer, three-axis modal acceleration sensor, first load sensor, and the second load sensor is arranged on excitation force hammer, and three-axis modal acceleration sensor is arranged on the root of blade to be measured, and first load sensor is arranged on drive arrangement, and data acquisition instrument is connected with three-axis modal acceleration sensor, first load sensor, second load sensor, drive arrangement and computer respectively.

[0007] The positioning hole is arranged on each chuck half in the above scheme, the fixed half and the mobile half are provided with the positioning pin, the fixed half fixes one chuck half through the positioning pin and the positioning hole, and the mobile half fixes the other chuck half through the positioning pin and the positioning hole.

[0008] The fixed half is fixed on the bolster through the bolt in the above scheme, and the mobile half is connected with the drive arrangement through the trunnion support.

[0009] The three-axis modal acceleration sensor is located at the central position of the upper side of the blade root of the blade to be measured in the above scheme.

[0010] The blade to be measured is the blade of a steam turbine in the above scheme, which comprises a fir-tree shaped blade root and a blade body, and the mortise of the mortise chuck is matched with the tenon and the lower edge plate of the blade of the steam turbine.

[0011] The blade body of the blade of the steam turbine comprises a blade basin surface and a blade back surface, and the knocking point is located at 3-5 mm of the top close to the inlet edge of the blade body.

[0012] The utility model has the following beneficial effects:

[0013] The utility model can be suitable for the damage detection of rotating machinery blades with different root shapes, the operation steps are simple, the on-site detection is convenient, different test pieces can be ensured to be in the same clamping working condition, and the accuracy of the detection data is improved.

[0014] The blade clamping device is simple in structure, can realize the same clamping force each time, ensures that the test conditions of different test pieces are consistent, and can effectively ensure the precision of vibration test.

[0015] 3、The utility model discloses a data acquisition instrument is connected with three -axis modal acceleration sensor and two load sensors, collects, records and analyzes data, and control drive arrangement realizes the clamping force of each time to the blade under test keeps consistent, BRIEF DESCRIPTION OF DRAWINGS

[0016] Fig. 1 It is the structural diagram of the utility model.

[0017] Fig. 2 It is the working flow diagram of the utility model.

[0018] In the drawing: 1 blade under test;2 three -axis modal acceleration sensor;3 mortise chuck;4 blade clamp;5 drive arrangement;6 first load sensor;7 trunnion support;8 positioning pin;9 bed;10 compression bolt;11 knock point;12 second load sensor;13 excitation force hammer;14 data acquisition instrument;15 computer. DETAILED DESCRIPTION

[0019] The utility model will be further explained in connection with the drawings:

[0020] Combination Figs. 1-2 As shown in the figure, this kind of damage detection system of rotating machinery blade based on vibration includes blade clamping device, signal detection device, the blade clamping device includes blade clamp 4, mortise chuck 3, drive arrangement 5, bed 9, the blade clamp 4 is the clamping body of open upper end by the fixed half and the mobile half and is buckled, the fixed half has sliding seat, the mobile half is slidably connected on the sliding seat, the fixed half is fixedly connected on one side of bed 9, the mobile half is connected drive arrangement 5, and drive arrangement 5 is connected with the other side of bed 9 through trunnion support 7;Mortise chuck 3 is formed by two chuck halves, and the chuck half is fixed on the fixed half, and the other chuck half is fixed on the mobile half, and the mortise formed after the buckling of two chuck halves is matched with the tenon of the root of blade under test 1;Signal detection device includes data acquisition instrument 14, computer 15, excitation force hammer 13, three -axis modal acceleration sensor 2, first load sensor 6, and second load sensor 12 is arranged on excitation force hammer 13, three -axis modal acceleration sensor 2 is arranged at the root of blade under test, first load sensor 6 is arranged on drive arrangement 5, and data acquisition instrument 14 is connected with three -axis modal acceleration sensor 2, first load sensor 6, second load sensor 12, drive arrangement 5 and computer 15 respectively.

[0021] The blade clamping device is used for fixing the collet 3 and locking the blade to be tested 1, so as to ensure that the blade to be tested does not displace or fall off during the detection process; the blade clamp 4 is provided with a positioning pin 8 on the bottom, one end of the blade clamp 4 is connected with the support table 9, and the other end is connected with the driving device 5; the mortise and tenon joint collet 3 is customized and designed according to the specific shape and size of the blade root, so as to ensure that the collet matches the mortise of the blade root, and the bottom is provided with a positioning hole facilitating replacement of different shaped collets; the driving device 5 adopts force control technology, which is used to ensure that the mortise and tenon joint collet 3 is fixed to the blade clamp 4 with the same clamping force each time; the support table 9 is used to support and fix the blade clamp 4 and the driving device 5; and the driving device 5 is precisely controlled by the data acquisition instrument control module in the signal detection device, so as to ensure that the test pieces have consistent working conditions.

[0022] The signal detection device is used for collecting and analyzing the vibration acceleration signals of the test pieces and performing data processing to obtain the modal frequency of the measured blade, and the functions further include applying a pulse force and controlling the required clamping force. The excitation force hammer 13 is used to provide the pulse force required for the vibration of the flue gas turbine blade; the three-axis modal acceleration sensor is located at the central position on the upper side of the blade root, and the three-axis modal acceleration sensor 2 is used to collect the measured vibration acceleration signals of the blade after being subjected to the pulse force; the first load sensor 6 and the second load sensor 12 are used to collect the pulse force signals provided by the excitation force hammer 13 and the size of the clamping force provided by the driving device 5; the data acquisition instrument 14 is connected with the three-axis modal acceleration sensor 2, the first load sensor 6 and the second load sensor 12, and is used to collect, record and analyze data, and control the driving device 5 to keep the clamping force on the test pieces consistent each time; the computer 15 is connected with the data acquisition instrument 14, and tests and analyzes the collected data to obtain the modal frequency of the measured blade.

[0023] The driving device in the blade clamping device is adjusted by the control module in the data acquisition instrument, and the control mode is load control, real-time feedback is obtained according to the load sensor on one side of the driving device, and precise control of the clamping force is realized. Embodiment 1

[0024] In this embodiment, the flue gas turbine rotor blade is taken as an example as the test piece for damage detection. This vibration-based rotating machinery blade damage detection system comprises:

[0025] The blade clamping device is used for clamping and fixing the test piece, the test piece is a flue gas turbine rotor blade, and the flue gas turbine blade comprises a fir tree-shaped blade root and a blade body.

[0026] Signal detection device for collecting and analyzing vibration acceleration signal of the test piece and processing data to obtain modal frequency of the measured blade, the device comprising driving device required for blade clamping, excitation force hammer, data acquisition instrument and the like, the functions comprising applying pulse force and controlling the size of the required clamping force, the three-axis modal acceleration sensor is located at the central position on the upper side of the blade root.

[0027] The blade clamping device comprises a blade clamp 4, an upper base of the blade clamp 4 is provided with a positioning pin 8 for positioning and replacing different shaped chuck, and a threaded hole is formed at one end of the blade clamp 4 for fixing to the support table 9 through a compression bolt 10;

[0028] A mortise and tenon chuck 3 is provided with a mortise and tenon groove matched with the blade root clamping part, and a positioning hole is formed at the bottom for replacing different shaped chuck;

[0029] The compression bolt 10 is matched with the threaded hole and used for fixing the blade clamp 4 to the support table 9;

[0030] One end of the driving device 5 is connected to the support table 9 through an ear shaft support 7, the front end of the piston rod is connected to one end of the blade clamp 4 with a sliding rail through the ear shaft support 7, and the driving device 5 is supported by a bracket or a base in a horizontal state;

[0031] A threaded hole is formed at one end of the support table 9 for fixing the fixed half of the blade clamp 4 through the compression bolt 10, and one end is connected to the driving device 5 through the ear shaft support 7 by screw connection.

[0032] In the embodiment, the piston rod of the driving device 5 is extended to move the blade clamp 4 in the positive direction of the sliding rail arranged at the bottom, so that the mortise and tenon chuck 3 on the blade clamp 4 is extruded to fix and lock the flue gas turbine blade (the test blade 1) (that is, one chuck half moves with the moving half, moves to the other chuck half, and fixes and locks the flue gas turbine blade 1). The blade clamp 4 is provided with a positioning pin 8 at the bottom, and the positioning pin 8 is used for positioning the mortise and tenon chuck 3 on the blade clamp 4. The blade clamp 4 is provided with an ear shaft support 7 at one end (that is, the moving half), and the front end of the piston rod of the driving device 5 is connected to the ear shaft support 7 by screw connection, so as to clamp and fix the flue gas turbine blade. One end of the driving device 5 is connected to the support table 9 through the ear shaft support 7, and a clearance ring is arranged between the driving device 5 and the ear shaft support 7.

[0033] The blade clamping device of the embodiment has simple structure, can apply the same clamping force each time, ensures that the test conditions of different test pieces are consistent, and can effectively ensure the precision of vibration test.

[0034] The signal detection device comprises:

[0035] The excitation force hammer 13 is connected to the data acquisition instrument 14 and used for applying pulse force to the flue gas turbine blade;

[0036] Load sensor 12 is located on the excitation force hammer 13, for real-time feedback of the applied pulse force signal;

[0037] Triaxial modal acceleration sensor 2 is a contact type measurement, which converts the pressure signal into an electrical signal through piezoelectric conversion and inputs the data collection instrument 14 for receiving the vibration acceleration signal generated by the test piece;

[0038] Load sensor 6 is connected to one end of driving device 5, for receiving the applied clamping force, ensuring consistent clamping conditions of different test pieces;

[0039] Data collection instrument 14 is used to receive the signals collected by each sensor and control the driving device to apply the same clamping force;

[0040] Computer 15 is connected to data collection instrument 14, for testing and analyzing the signals received by each sensor of data collection instrument, obtaining the modal frequency of the flue gas turbine blade.

[0041] In this embodiment, the control module in the data collection instrument 14 is used to keep the load applied by the driving device 5 consistent each time, and the control mode is load control. Load sensor 6 is installed at the end connected to the driving device 5 and the table 9, and the load applied is precisely controlled by real-time feedback of the load sensor 6 and setting its full scale range, and PID adjustment is used to complete the clamping and fixing of the flue gas turbine blade by the driving device 5, so that different test pieces have consistent clamping conditions, ensuring the accuracy of the test results.

[0042] Triaxial modal acceleration sensor 2 is placed on the upper side of the flue gas turbine blade root, and the excitation force hammer 13 is used to vertically knock the knocking point 11 near the top 3-5 mm of the blade air inlet edge, to complete the collection of the blade vibration acceleration signal. Due to the limited size of the blade, the knocking point and the triaxial modal acceleration sensor position are kept consistent as much as possible, and the average value is taken after multiple knockings. When using the excitation force hammer to knock, the position and angle of the hammer are controlled as much as possible to avoid continuous knocking; the force of each hammer should be consistent. Load sensor 12 is provided on the excitation force hammer 13 to provide accurate knocking force measurement data. The excitation force hammer 13 is a market product, and its setting and connection use existing technology.

[0043] Data collection instrument 14 collects, records and transmits various signals collected by the sensor to computer 15, and the test analysis software in computer 15 completes the test analysis of the data, converts the vibration acceleration signal into modal frequency through frequency response function analysis and modal parameter extraction, completes the modal frequency extraction of the measured blade and compares it with the modal frequency parameter of the non-destructive blade, and views the damage state of the measured blade.

Claims

1. A damage detection system for rotating mechanical blades based on vibration, characterized in that: The vibration-based damage detection system for the rotating machinery blade comprises a blade clamping device and a signal detection device. The blade clamping device comprises a blade clamp, a tenon-and-slot chuck, a driving device and a support table. The blade clamp is an open-end clamping body formed by a fixed half and a movable half. The fixed half has a sliding seat, and the movable half is slidably connected to the sliding seat. The fixed half is fixedly connected to one side of the support table, and the movable half is connected to the driving device. The driving device is connected to the other side of the support table through an ear shaft support. The tenon-and-slot chuck is formed by two chuck halves. One chuck half is fixed to the fixed half, and the other chuck half is fixed to the movable half. The tenon-and-slot formed by the two chuck halves after buckling matches the tenon of the root of the blade to be detected. The signal detection device comprises a data acquisition instrument, a computer, an excitation hammer, a three-axis modal acceleration sensor, a first load sensor, a second load sensor arranged on the excitation hammer, the three-axis modal acceleration sensor arranged at the root of the blade to be detected, and the first load sensor arranged on the driving device. The data acquisition instrument is connected to the three-axis modal acceleration sensor, the first load sensor, the second load sensor, the driving device and the computer respectively.

2. A vibration-based system for detecting damage to a blade of a rotating machine as recited in claim 1, wherein: Positioning holes are arranged on the chuck halves, and the fixed half and the movable half are provided with positioning pins. The fixed half fixes one chuck half through the positioning pins and the positioning holes, and the movable half fixes the other chuck half through the positioning pins and the positioning holes.

3. A vibration-based system for detecting damage to a blade of a rotating machine as recited in claim 2, wherein: The fixed half is fixed to the support table through bolts, and the movable half is connected to the driving device through the ear shaft support.

4. A vibration-based system for detecting damage to a blade of a rotating machine as recited in claim 3, wherein: The three-axis modal acceleration sensor is located at the central position of the upper end of the blade root of the blade to be detected.

5. A vibration-based system for detecting damage to a blade of a rotating machine as recited in claim 4, wherein: The blade to be detected is a steam turbine blade, which comprises a fir tree-shaped blade root and a blade body. The tenon-and-slot chuck matches the tenon and the lower edge plate of the steam turbine blade.

6. A vibration-based system for detecting damage to a blade of a rotating machine as defined in claim 5, wherein: The blade body of the steam turbine blade comprises a blade pressure surface and a blade suction surface. The knocking point is located at 3-5 mm from the top of the inlet edge of the blade body.

Images