Excitation precision loading method and device for turbine blade shroud damper system
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- AECC HUNAN AVIATION POWERPLANT RES INST
- Filing Date
- 2026-03-31
- Publication Date
- 2026-06-09
Smart Images
Figure CN122171141A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of testing equipment technology, and specifically to a method and apparatus for precise excitation loading of a turbine blade rim damper system. Background Technology
[0002] With the increasing demands for power-to-weight ratio and thrust-to-weight ratio in aero-engines, engine structures are evolving towards lightweight design and high structural efficiency. Turbine flow components, especially rotor blades, not only require higher aerodynamic efficiency but also necessitate thinner blade profiles (some less than 3mm thick) and increased blade height to achieve greater work capacity. Simultaneously, rotor blades must withstand extremely high vibration loads, centrifugal loads, thermal loads, and aerodynamic loads during engine operation. However, thin and long rotor blades are prone to high-frequency harmful vibrations under high-temperature, high-pressure combustion gas excitation and disk airflow excitation. In particular, turbine blades are highly susceptible to cracking and fracture after high-cycle fatigue vibration, which can lead to blade ejection and damage to turbine components, or even catastrophic engine consequences. Therefore, the vibration problem of rotor blades subjected to airflow excitation and high-speed rotation is a pressing issue for aero-engine designers.
[0003] To understand the vibration characteristics of turbine rotor blades, blade vibration characteristic testing is an essential research component, and industry scholars have conducted extensive research. Vibration table testing of blades / disks is an important testing method used to evaluate the vibration characteristics and structural integrity of blades and disks under simulated operating conditions. This testing is crucial for ensuring the safety and reliability of aero-engines. During vibration table testing, an electromagnetic vibration table is typically used to excite the blades, while strain gauges are used to measure the stress distribution. Non-contact eddy current sensors can be used to measure the blade's natural frequencies, while sand-throwing can be used to determine the mode shapes. These tests allow us to understand the blade's natural frequencies and vibration stress levels, and analyze the influence of different factors on these characteristics. Furthermore, modal analysis methods, such as the impact test, are used to study the blade's vibration modes. This method identifies the blade's vibration characteristics by striking the blade and measuring its response. Comparing the results obtained from the modal method with the results from the vibration table resonance method verifies the correctness of the resonance method. Gas excitation testing is a test method that simulates the periodic aerodynamic excitation of blades under actual operating conditions. Such experiments are crucial for understanding and predicting the vibration behavior of blades under actual operating conditions, as they help assess the blade's vibration characteristics and the vibration reduction effect of damping devices. Researchers have conducted numerous high-frequency gas-solid coupling experiments since early on. In the 1970s, RR in the UK developed a gas-excited testing device capable of studying engine blade vibration faults and performing large-scale blade vibration fatigue tests. In 2012, the Shenyang Engine Design Institute of AVIC developed a whistle-type high-frequency gas-excited testing device, completing vibration characteristic tests on a single non-rotating blade using gas excitation. Furthermore, rotating test bench excitation testing is a method that can be used to test the damping characteristics of blades and conduct high-cycle fatigue performance tests.
[0004] In terms of blade excitation load application, four common excitation methods are: atomized oil droplet excitation, airflow excitation, mechanical excitation, and dynamic load simulation. Atomized oil droplet excitation: This method simulates the periodic aerodynamic excitation of turbine blades by spraying atomized oil droplets through a nozzle. This technology can achieve non-contact excitation under high-speed rotation and is suitable for testing the vibration characteristics of high-pressure turbine rotor blades. This excitation method effectively replicates the connection between the rotor blade and the rotor disk and can obtain realistic blade vibration characteristics and damping reduction effects. Airflow excitation: Airflow excitation is a non-contact excitation method that applies periodic loads to the blades through airflow. This method is very effective in simulating the aerodynamic environment under real working conditions, but it may lead to a decrease in the vacuum level of the test system, thereby increasing system damping. Mechanical excitation: Vibration is directly applied using an electromagnetic exciter or vibration table, allowing for precise control of the excitation frequency and amplitude. This method is suitable for vibration testing under static or low-speed conditions, but its application under high-speed rotation is limited. Dynamic load simulation: This method can simulate the dynamic loads that blades experience in actual operation, including centrifugal force, aerodynamic force, and thermal stress. This method helps to evaluate the performance and reliability of blades under extreme conditions.
[0005] Therefore, current research on the vibration reduction characteristics of turbine blade rim dampers mainly focuses on static tests and simulating the application of centrifugal force to the dampers. While these two aspects have been extensively studied and numerous experimental setups exist, precise excitation loading methods are lacking. Furthermore, for excitation loads on blades, gas excitation methods cannot measure the vibration characteristics of the blades under actual rotational conditions, and rotating test bench excitation technology presents operational difficulties in both excitation and vibration measurement. Summary of the Invention
[0006] This invention provides a method and apparatus for precise excitation loading of a turbine blade rim damper system to solve the above-mentioned problems.
[0007] This invention provides a method for precise excitation loading of a turbine blade rim damper system, comprising the following steps: Specimen installation: The blade and a pair of edge plates are fixed to the test platform using experimental fixtures; the pair of edge plates are located on opposite sides of the blade; the blade is an equivalent flat blade or a real characteristic blade; Install and adjust the damper: Place a damper between the blade and the edge plate on each side, pass the wire rope through the damper, and apply tension to the wire rope to make the damper contact and squeeze the edge plate to generate positive pressure; a tension gauge connected to the wire rope is used to measure the tension, and the magnitude of the positive pressure is precisely adjusted by adjusting the tension of the wire rope. Excitation and Testing: The exciter is connected to the tip of the blade via a connecting rod, and a force sensor is installed on the connecting rod. An excitation signal is generated by a signal generation module and driven by a power amplifier to apply an excitation force to the tip of the blade. The frequency and amplitude of the excitation force are adjusted and controlled by the power amplifier and a signal acquisition instrument. During the test, the excitation force is acquired in real time by the force sensor, and the displacement response of the blade is acquired by a laser displacement sensor. Analysis of vibration reduction characteristics: Based on the collected excitation force and displacement response, the vibration and vibration reduction characteristics of the blade under different normal pressure values and different excitation force parameters are analyzed.
[0008] The method provided by this invention uses a scaled-down (specifically 5 times) flat blade to test the vibration reduction effect of the rim damper and correct the calculation method. Finally, vibration reduction experiments of the rim damper are conducted on a scaled-down blade with the actual blade structure characteristics, and the vibration reduction characteristics are obtained. Furthermore, this method, by adjusting the power amplifier and signal acquisition instrument, enables the excitation frequency and excitation force amplitude to reach the target values, accurately controlling the magnitude of the excitation force amplitude and frequency. The exciter and blade are connected by a connecting rod, allowing the exciter to apply an external excitation force to the blade tip, thus obtaining the influence law of the ideal blade vibration and vibration reduction characteristics under different conditions.
[0009] Real turbine blades have complex shapes. While using real blades as experimental specimens can accurately simulate the actual motion response of the blade-shroud damper system and yield more realistic experimental results, the actual turbine blades of small and medium-sized aero-engines are small, with a blade height typically less than 30mm, making them difficult to clamp and measure. This invention uses a 5x magnified blade as the experimental specimen while retaining the true shape of the blade. Furthermore, the complex shape of real blades makes it difficult to apply excitation. In this invention, the exciter is connected to the blade tip via a connecting rod. After assembly, the connecting rod indirectly applies excitation to the blade.
[0010] In one alternative implementation, both the equivalent flat blade and the real feature blade are models that are equivalent to and geometrically scaled up based on the modal parameters of a real turbine blade.
[0011] In one alternative implementation, the magnification ratio is 5x.
[0012] In one alternative implementation, the exciter is connected to the tip of the blade via a threaded rod.
[0013] In one alternative implementation, the frequency and amplitude of the excitation force are adjusted to the target values by adjusting the power amplifier and the signal acquisition device.
[0014] Secondly, the present invention also provides a device for precise excitation loading, comprising: The test specimen module includes blades, a pair of flanges, and a pair of dampers; The installation and loading module includes an experimental fixture for fixing the blade and the edge plate, a steel wire rope for applying tension to the damper, and a tension gauge adjustment device for measuring and adjusting the tension. The excitation and testing module includes an exciter for applying excitation force to the blade, a connecting rod for connecting the exciter and the blade tip, a force sensor disposed on the connecting rod, a signal generation module and a power amplifier for generating and adjusting excitation signals, a signal acquisition instrument for acquiring signals, and a laser displacement sensor for measuring the displacement response of the blade.
[0015] In one alternative embodiment, the experimental fixture includes a fixture steel plate platform, wherein the first natural frequency of the fixture steel plate platform is more than three times the first natural frequency of the blade.
[0016] In one alternative embodiment, the tension gauge adjustment device includes an industrial-grade tension gauge and an adjusting bolt, the tension of the wire rope being adjusted by moving the adjusting bolt forward and backward.
[0017] In one alternative implementation, the excitation and testing module further includes an exciter suspension bracket for mounting and fixing the exciter.
[0018] In one optional embodiment, the blade has a mounting base plate with a plurality of mounting holes. A boss is provided on one side of the mounting base plate, and the boss is used to abut against the damper. Attached Figure Description
[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0020] Figure 1 This is a schematic diagram of an excitation precision loading device according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a blade (equivalent flat plate blade) in an excitation precision loading device according to an embodiment of the present invention. Figure 3 This is a physical image of a blade in a precision loading device according to an embodiment of the present invention; Figure 4This is a schematic diagram of the damper structure (actual blade feature) in an excitation precision loading device according to an embodiment of the present invention. Figure 5 This is a schematic diagram of the structure of a blade in an excitation precision loading device according to an embodiment of the present invention; Figure 6 This is a physical image of a tension gauge in an excitation precision loading device according to an embodiment of the present invention; Figure 7 This is a physical diagram of the vibrator suspension bracket in an excitation precision loading device according to an embodiment of the present invention.
[0021] Explanation of reference numerals in the attached figures: 1. Leaves; 2. Edge plate; 3. Experimental fixtures; 4. Dampers; 5. Steel wire rope; 6. Force gauge; 7. Vibrator; 8. Force sensor; 9. Power amplifier; 10. Signal acquisition instrument; 11. Laser displacement sensor; 12. Computer; 13. Signal generation module. Detailed Implementation
[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0023] With the increasing demands for power-to-weight ratio and thrust-to-weight ratio in aero-engines, engine structures are evolving towards lightweight design and high structural efficiency. Turbine flow components, especially rotor blades, not only require higher aerodynamic efficiency but also necessitate thinner blade profiles (some less than 3mm thick) and increased blade height to achieve greater work capacity. Simultaneously, rotor blades must withstand extremely high vibration loads, centrifugal loads, thermal loads, and aerodynamic loads during engine operation. However, thin and long rotor blades are prone to high-frequency harmful vibrations under high-temperature, high-pressure combustion gas excitation and disk airflow excitation. In particular, turbine blades are highly susceptible to cracking and fracture after high-cycle fatigue vibration, which can lead to blade ejection and damage to turbine components, or even catastrophic engine consequences. Therefore, the vibration problem of rotor blades subjected to airflow excitation and high-speed rotation is a pressing issue for aero-engine designers.
[0024] To understand the vibration characteristics of turbine rotor blades, blade vibration characteristic testing is an essential research component, and industry scholars have conducted extensive research. Vibration table testing of blades / disks is an important testing method used to evaluate the vibration characteristics and structural integrity of blades and disks under simulated operating conditions. This testing is crucial for ensuring the safety and reliability of aero-engines. During vibration table testing, an electromagnetic vibration table is typically used to excite the blades, while strain gauges are used to measure the stress distribution. Non-contact eddy current sensors can be used to measure the blade's natural frequencies, while sand-throwing can be used to determine the mode shapes. These tests allow us to understand the blade's natural frequencies and vibration stress levels, and analyze the influence of different factors on these characteristics. Furthermore, modal analysis methods, such as the impact test, are used to study the blade's vibration modes. This method identifies the blade's vibration characteristics by striking the blade and measuring its response. Comparing the results obtained from the modal method with the results from the vibration table resonance method verifies the correctness of the resonance method. Gas excitation testing is a test method that simulates the periodic aerodynamic excitation of blades under actual operating conditions. Such experiments are crucial for understanding and predicting the vibration behavior of blades under actual operating conditions, as they help assess the blade's vibration characteristics and the vibration reduction effect of damping devices. Researchers have conducted numerous high-frequency gas-solid coupling experiments since early on. In the 1970s, RR in the UK developed a gas-excited testing device capable of studying engine blade vibration faults and performing large-scale blade vibration fatigue tests. In 2012, the Shenyang Engine Design Institute of AVIC developed a whistle-type high-frequency gas-excited testing device, completing vibration characteristic tests on a single non-rotating blade using gas excitation. Furthermore, rotating test bench excitation testing is a method that can be used to test the damping characteristics of blades and conduct high-cycle fatigue performance tests.
[0025] In terms of blade excitation load application, four common excitation methods are: atomized oil droplet excitation, airflow excitation, mechanical excitation, and dynamic load simulation. Atomized oil droplet excitation: This method simulates the periodic aerodynamic excitation of turbine blades by spraying atomized oil droplets through a nozzle. This technology can achieve non-contact excitation under high-speed rotation and is suitable for testing the vibration characteristics of high-pressure turbine rotor blades. This excitation method effectively replicates the connection between the rotor blade and the rotor disk and can obtain realistic blade vibration characteristics and damping reduction effects. Airflow excitation: Airflow excitation is a non-contact excitation method that applies periodic loads to the blades through airflow. This method is very effective in simulating the aerodynamic environment under real working conditions, but it may lead to a decrease in the vacuum level of the test system, thereby increasing system damping. Mechanical excitation: Vibration is directly applied using an electromagnetic vibrator or vibration table, allowing for precise control of the excitation frequency and amplitude. This method is suitable for vibration testing under static or low-speed conditions, but its application under high-speed rotation is limited. Dynamic load simulation: This method can simulate the dynamic loads experienced by the blades during actual operation, including centrifugal force, aerodynamic force, and thermal stress. This method helps to evaluate the performance and reliability of blades under extreme conditions.
[0026] Therefore, current research on the vibration reduction characteristics of turbine blade rim dampers mainly focuses on static tests and simulating the application of centrifugal force to the dampers. While these two aspects have been extensively studied and numerous experimental setups exist, precise excitation loading methods are lacking. Furthermore, for excitation loads on blades, gas excitation methods cannot measure the vibration characteristics of the blades under actual rotational conditions, and rotating test bench excitation technology presents operational difficulties in both excitation and vibration measurement.
[0027] The following is combined Figures 1 to 7 The following describes embodiments of the present invention.
[0028] According to an embodiment of the present invention, a method for precise excitation loading of a turbine blade rim damper system is provided, comprising the following steps: Specimen installation: Fix blade 1 and a pair of edge plates 2 to the test platform using experimental fixture 3; the pair of edge plates 2 are located on opposite sides of blade 1; blade 1 is an equivalent flat blade or a real characteristic blade; Specifically, blade 1 is secured to experimental fixture 3 with bolts via its mounting base plate to ensure a firm installation. Subsequently, a pair of edge plates 2 are respectively mounted and fixed on the fixture platform on opposite sides (i.e., the pressure side and suction side) of blade 1 to simulate the interaction interface between two adjacent blades 1 and the blade under test 1.
[0029] Install and adjust the damper 4: Place a damper 4 between the blade 1 and the edge plate 2 on each side, so that the wire rope 5 passes through the damper 4. By applying tension to the wire rope 5, the damper 4 contacts and squeezes the edge plate 2 to generate positive pressure. The tension gauge 6 connected to the wire rope 5 is used to measure the tension and to precisely adjust the magnitude of the positive pressure by adjusting the tension of the wire rope 5. Specifically, a damper 4 is placed in each of the gaps between the two rim plates 2 and the blade body 1. A high-strength steel wire rope 5 is passed sequentially through pre-drilled holes in the two dampers 4. Both ends of the steel wire rope 5 are connected to a tension gauge 6 adjustment device. An axial tension is applied to the steel wire rope 5 by operating this adjustment device (e.g., rotating the adjusting bolt). This tension is transmitted through the dampers 4, causing them to come into close contact with the rim plates 2 on both sides and generate compression, thus generating a positive pressure at the contact interface. The tension gauge 6 connected to the steel wire rope 5 is used to measure this tension value in real time. By adjusting the tension of the steel wire rope 5, the positive pressure can be precisely adjusted to the desired value.
[0030] Excitation and testing: The exciter 7 is connected to the tip of the blade 1 via a connecting rod, and a force sensor 8 is installed on the connecting rod; an excitation signal is generated by the signal generation module 13, which drives the exciter 7 via the power amplifier 9, thereby applying an excitation force to the tip of the blade 1. The frequency and amplitude of the excitation force are adjusted and controlled by the power amplifier 9 and the signal acquisition instrument 10; during the test, the excitation force is collected in real time by the force sensor 8, and the displacement response of the blade 1 is collected by the laser displacement sensor 11. Specifically, the output end of the exciter 7 is mechanically fixed to the tip of the blade 1 via a connecting rod. A force sensor 8 is installed in series on the connecting rod. The probe of the laser displacement sensor 11 is aligned with a pre-selected measurement point at the tip of the blade 1.
[0031] The test system is started, and a sinusoidal electrical signal with a set frequency and amplitude is generated by the signal generation module 13. This signal is amplified by the power amplifier 9 and drives the exciter 7. The exciter 7 converts the electrical signal into mechanical vibration, and the resulting excitation force is transmitted through the connecting rod and force sensor 8 and applied to the tip of the blade 1. During this process, by adjusting the relevant parameters of the power amplifier 9 and the signal acquisition instrument 10, the frequency and amplitude of the excitation force ultimately applied to the blade 1 can be precisely controlled and stably maintained.
[0032] During the test, force sensor 8 picks up and outputs the excitation force signal actually acting on blade 1 in real time; at the same time, laser displacement sensor 11 picks up and outputs the displacement response signal generated by the vibration of the tip of blade 1 in real time. Both signals are transmitted to signal acquisition instrument 10 for synchronous acquisition and recording.
[0033] Analyze the vibration damping characteristics: Based on the collected excitation force and displacement response, analyze and obtain the vibration and vibration damping characteristics of blade 1 under different normal pressure values and different excitation force parameters.
[0034] Specifically, after completing one test, import the collected excitation force time-domain signal and displacement response time-domain signal into data analysis software (such as the Econ analysis module supporting the signal collector 10). Through methods such as spectrum analysis and amplitude calculation, the vibration response level of blade 1 under the current specific normal pressure and excitation force parameters can be obtained.
[0035] To study the rules, the second to fourth steps can be repeated by changing the experimental conditions: Firstly, adjust to different normal pressure values in the second step, and keep the same excitation frequency and amplitude in the third step, so as to analyze the influence rule of normal pressure on the vibration damping characteristics; Secondly, keep a certain normal pressure value unchanged in the second step, and change the frequency or amplitude of the excitation force in the third step, so as to analyze the influence rule of excitation parameters on the vibration damping characteristics.
[0036] In this embodiment, the test platform mainly includes three parts: test specimens, installation equipment, and test equipment. The test specimens include a blade 1 to be tested (which can be an equivalent flat blade or a real feature blade with real geometric features), a pair of flange plates 2, and a damper 4. The bottom of blade 1 is designed with an installation base plate for connecting with the installation equipment. The flange plates 2 are used to simulate the constraints of adjacent blades 1 on the measured blade 1. The installation equipment mainly includes a cast iron platform and an experimental fixture 3. The experimental fixture 3 is used to rigidly fix blade 1 and flange plates 2. It also includes a set of tension gauge 6 adjustment devices for applying and adjusting pressure to the damper 4. The test equipment mainly includes an excitation application module and a data acquisition module. The excitation application module includes a vibrator 7, a power amplifier 9, and a signal generation module 13 for generating excitation signals (such as the Econ software integrated in the computer 12). The data acquisition module includes a force sensor 8 for measuring the input excitation force, a laser displacement sensor 11 for measuring the tip displacement response of blade 1, and a signal collector 10 for collecting and processing all sensor signals.
[0037] In one embodiment, both the equivalent flat blade 1 and the real feature blade 1 are models scaled up according to the real turbine blade 1.
[0038] The method provided in this embodiment uses a scaled-up (specifically five times) flat blade 1 to test the vibration reduction effect of the rim plate 2 damper 4 and correct the calculation method. Finally, a vibration reduction experiment of the rim plate 2 damper 4 is conducted on a scaled-up blade 1 with real blade structure characteristics, and the vibration reduction characteristics are obtained. Furthermore, this method adjusts the power amplifier 9 and the signal acquisition instrument 10 to achieve the target values for the excitation frequency and excitation force amplitude, accurately controlling the magnitude of the excitation force amplitude and frequency. The exciter 7 and blade 1 are connected by a connecting rod, allowing the exciter 7 to apply an external excitation force to the tip of blade 1, thus obtaining the influence law of the ideal blade 1 vibration and vibration reduction characteristics under different conditions.
[0039] The actual turbine blade 1 has a complex shape. While using the actual blade 1 as the experimental specimen could accurately simulate the actual motion response of the blade plate 2, damper 4, and blade 1 system, yielding more realistic experimental results, the actual turbine blade 1 of small and medium-sized aero-engines is relatively small, with a blade height typically less than 30mm, making it difficult to clamp and measure. This embodiment retains the actual shape of blade 1 while using a 5x magnified blade 1 as the experimental specimen. Furthermore, the complex shape of the actual blade 1 makes it difficult to apply excitation. In this embodiment, the exciter 7 is connected to the tip of blade 1 via a connecting rod. After assembly, the connecting rod indirectly applies excitation to blade 1.
[0040] In one embodiment, the vibrator 7 is connected to the tip of the blade 1 via a threaded rod. For example, an internally threaded hole is pre-machined at the tip of the blade 1, or a connecting block with an internal thread is fixed thereon.
[0041] In one embodiment, the frequency and amplitude of the excitation force are adjusted to the target value by adjusting the power amplifier 9 and the signal acquisition device 10.
[0042] Secondly, embodiments of the present invention also provide an excitation precision loading device, including a test specimen module, an installation and loading module, and an excitation and testing module. The test specimen module includes a blade 1, a pair of edge plates 2, and a pair of dampers 4. The installation and loading module includes an experimental fixture 3 for fixing the blade 1 and the edge plates 2, a steel wire rope 5 for applying tension to the dampers 4, and a tension gauge 6 for measuring and adjusting the tension. The excitation and testing module includes an exciter 7 for applying excitation force to the blade 1, a connecting rod for connecting the exciter 7 and the tip of the blade 1, a force sensor 8 disposed on the connecting rod, a signal generation module 13 and a power amplifier 9 for generating and adjusting excitation signals, a signal acquisition instrument 10 for acquiring signals, and a laser displacement sensor 11 for measuring the displacement response of the blade 1.
[0043] Blade 1 is a model made by scaling up a real turbine blade, such as... Figure 2As shown, it can be an equivalent flat blade with simplified geometry, such as... Figure 4 As shown, it can also be a real blade with actual blade shape characteristics. The bottom of blade 1 is designed with a mounting plate.
[0044] Two edge plates 2 are used to simulate the contact constraint between adjacent blades 1 and the tested blade 1 in an actual bladed disk. In the test, they are respectively set on opposite sides of the blade 1.
[0045] During testing, the two friction dampers 4 are placed between the blade 1 and the two side edge plates 2, respectively. The dampers 4 are designed with through holes for the steel wire rope 5 to pass through.
[0046] The experimental fixture 3 is a rigid mechanical fixing mechanism with two legs and a clamping steel plate platform fixed to the legs. The clamping steel plate platform is used to securely install and position the blade 1 and a pair of flanges 2 on the test platform (such as a cast iron platform). The wire rope 5 is a high-strength wire rope that passes through the through holes in a pair of dampers 4, and is used to apply tension to both dampers 4 simultaneously. The tension gauge 6 is an adjustment device connected to the end of the wire rope 5. It measures the real-time tension of the wire rope 5 through the tension gauge 6 inside; and changes the tension of the wire rope 5 through mechanical adjustment (such as rotating a screw), thereby continuously and accurately adjusting the tension acting on the dampers 4, and thus controlling the magnitude of the normal pressure between the dampers 4 and the flanges 2.
[0047] The exciter 7 is an actuator that converts electrical signals into mechanical forces (such as an electromagnetic exciter 7), and is the source of excitation. The connecting rod is a rigid rod used to mechanically connect the output end of the exciter 7 and the tip of the blade 1 to transmit the excitation force. The force sensor 8 is a sensor mounted in series on the connecting rod, used to measure the actual excitation force transmitted from the exciter 7 to the blade 1 in real time and in situ.
[0048] The signal generation module 13 (such as dedicated software in the computer 12) is used to generate an initial electrical excitation signal with the required frequency and amplitude. The power amplifier 9 is used to amplify the weak electrical signal output by the signal generation module 13 to drive the exciter 7. The two work together to regulate the excitation signal.
[0049] The signal acquisition device 10 is a data acquisition device used to synchronously acquire analog signals from all sensors such as the force sensor 8 and the laser displacement sensor 11, and convert them into digital signals for processing by the computer 12.
[0050] The laser displacement sensor 11 is a non-contact optical measuring instrument. Its probe is aligned with a specific position at the tip of the blade 1 to measure the vibration displacement response of the blade 1 under excitation in real time.
[0051] During testing, the installation and loading module fixes the test specimen module and applies precise normal pressure. Subsequently, the excitation and testing module is activated, and the signal generation module 13 generates a signal, which drives the exciter 7 via the power amplifier 9. The excitation force is applied to the tip of blade 1 through the connecting rod and force sensor 8, exciting blade 1 to vibrate. Simultaneously, the force sensor 8 and the laser displacement sensor 11 acquire the excitation force input and blade 1 displacement response output in real time, respectively, and these data are recorded by the signal acquisition instrument 10. Through the coordinated operation of these three modules, the entire device achieves precise loading and synchronous measurement of excitation and normal pressure.
[0052] In one embodiment, the experimental fixture 3 includes a fixture steel plate platform, the first natural frequency of which is more than three times the first natural frequency of the blade 1.
[0053] To prevent structural resonance between the fixture steel plate platform and the test object during testing, which could introduce additional systematic errors or distort test results, this embodiment specifies a clear design constraint on the ratio between the first-order natural frequency of the fixture steel plate platform and the first-order natural frequency of blade 1. Specifically, before the test begins, the first-order natural frequency of blade 1 is obtained through finite element simulation analysis or hammer impact modal testing. Subsequently, at least one of the following methods is used: topology optimization design, etc., to design the first-order natural frequency of the fixture steel plate platform to be more than three times the first-order natural frequency of blade 1.
[0054] By designing the first natural frequency of the fixture steel plate platform to be more than three times the first natural frequency of blade 1, when the excitation frequency sweeps within the working range, the fixture platform will not undergo modal coupling or resonant amplification with blade 1, ensuring that the measured vibration response comes entirely from blade 1 itself, rather than the parasitic response of the test system.
[0055] In one embodiment, the tension gauge 6 adjustment device includes an industrial-grade tension gauge and an adjustment bolt, which adjusts the tension of the wire rope 5 by moving the adjustment bolt forward or backward.
[0056] In one embodiment, such as Figure 7 As shown, the excitation and testing module also includes a suspension bracket for mounting and fixing the exciter 7.
[0057] In one embodiment, the blade 1 has a mounting base plate with a plurality of mounting holes; a boss is provided on one side of the mounting base plate for abutting against the damper 4.
[0058] like Figure 1 As shown, when installing the damper 4, the damper 4 abuts against this boss and the side wall of the flange 2, thus limiting its position. The mounting holes on the mounting base plate are used to insert bolts to fix the blade 1 to the experimental fixture 3.
[0059] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.
Claims
1. A method for precise excitation loading of a turbine blade rim damper system, characterized in that, Includes the following steps: Installation of the test specimen: The blade (1) and a pair of edge plates (2) are fixed to the test platform by the test fixture (3); the pair of edge plates (2) are respectively located on opposite sides of the blade (1); the blade (1) is an equivalent flat blade or a real characteristic blade; Install and adjust the damper (4): Place a damper (4) between the blade (1) and the edge plate (2) on each side, so that the wire rope (5) passes through the damper (4), and apply tension to the wire rope (5) so that the damper (4) contacts and squeezes the edge plate (2) to generate a positive pressure; a tension gauge (6) connected to the wire rope (5) is used to measure the tension, and the magnitude of the positive pressure is precisely adjusted by adjusting the tension of the wire rope (5); Apply excitation and test: Connect the exciter (7) to the tip of the blade (1) via a connecting rod, and set a force sensor (8) on the connecting rod; generate an excitation signal through the signal generation module (13), drive the exciter (7) through the power amplifier (9), thereby applying an excitation force to the tip of the blade (1), and adjust and control the frequency and amplitude of the excitation force through the power amplifier (9) and the signal acquisition instrument (10); during the test, the excitation force is collected in real time through the force sensor (8), and the displacement response of the blade (1) is collected through the laser displacement sensor (11); Analysis of vibration reduction characteristics: Based on the collected excitation force and displacement response, the vibration and vibration reduction characteristics of the blade (1) under different normal pressure values and different excitation force parameters are analyzed.
2. The method for precise excitation loading of a turbine blade rim damper system according to claim 1, characterized in that, Both the equivalent flat blade and the real feature blade are models that are equivalent to and geometrically enlarged based on the modal parameters of the real turbine blade (1).
3. The method for precise excitation loading of a turbine blade rim damper system according to claim 2, characterized in that, The magnification ratio is 5x.
4. The method for precise excitation loading of a turbine blade rim damper system according to claim 1, characterized in that, The exciter (7) is connected to the tip of the blade (1) via a threaded rod.
5. The method for precise excitation loading of a turbine blade rim damper system according to claim 1, characterized in that, By adjusting the power amplifier (9) and the signal acquisition device (10), the frequency and amplitude of the excitation force are made to reach the target values.
6. A device for precise excitation loading, characterized in that, include: The test specimen module includes a blade (1), a pair of flanges (2) and a pair of dampers (4); The installation and loading module includes an experimental fixture (3) for fixing the blade (1) and the edge plate (2), a steel wire rope (5) for applying tension to the damper (4), and a tension gauge (6) adjustment device for measuring and adjusting the tension. The excitation and testing module includes an exciter (7) for applying excitation force to the blade (1), a connecting rod for connecting the exciter (7) and the tip of the blade (1), a force sensor (8) disposed on the connecting rod, a signal generation module (13) and a power amplifier (9) for generating and adjusting excitation signals, a signal acquisition instrument (10) for acquiring signals, and a laser displacement sensor (11) for measuring the displacement response of the blade (1).
7. The excitation precision loading device according to claim 6, characterized in that, The experimental fixture (3) includes a fixture steel plate platform, the first natural frequency of which is more than three times the first natural frequency of the blade (1).
8. The excitation precision loading device according to claim 6, characterized in that, The tension gauge (6) adjustment device includes an industrial-grade tension gauge (6) and an adjustment bolt, and the tension of the wire rope (5) is adjusted by moving the adjustment bolt forward and backward.
9. The excitation precision loading device according to claim 6, characterized in that, The excitation and testing module also includes an exciter (7) suspension bracket for mounting and fixing the exciter (7).
10. The excitation precision loading device according to claim 6, characterized in that, The blade (1) has a mounting base plate, and the mounting base plate is provided with a plurality of mounting holes; A boss is provided on one side of the mounting base plate, and the boss is used to abut against the damper (4).