Blade vibration testing device with adjustable excitation angle

Abstract

The utility model provides a blade vibration testing device with an adjustable excitation angle, which belongs to the technical field of aero-engines and comprises a base, a vice, a blade group, an excitation block, a rotary table, an excitation module and a data acquisition module. The vice is fixedly mounted on the base; the blade group comprises a plurality of blades and is fixed on the vice; the excitation block is provided with an inclined surface and is fixedly mounted on one side surface; the rotary table is fixedly mounted on the base; the vibration excitation module comprises a vibration excitation rod and a modal vibration exciter, one end of the vibration excitation rod is fixedly connected to the modal vibration exciter, and the end face of the other end of the vibration excitation rod is fixedly connected with the inclined face of a vibration excitation block on the blade. The rotary table is used for adjusting the angle of the excitation rod so that the excitation rod can be perpendicular to the inclined face. According to the blade vibration device designed by the utility model, the excitation rod utilizes the excitation block vertically connected with the excitation rod, so that the excitation force applied by the excitation rod is decomposed to two directions of blade vibration, further multi-direction excitation can be carried out on the blade, and the test is closer to the actual working condition.

Description

Technical Field

[0001] This utility model belongs to the field of aero-engine technology, specifically relating to a blade vibration testing device with adjustable excitation angle. Background Technology

[0002] During operation, the axial-flow turbine rotor blades used in machines such as aero engines and gas turbines are subject to vibration due to the fluctuation of aerodynamic pressure on the blade surface over time. If effective measures are not taken to reduce the vibration level, the service life of the blades will be reduced, and the blades may even break due to excessive stress from the vibration, causing damage to the engine.

[0003] Blades are a crucial component of engines. Prolonged operation at high speeds can easily induce resonance, leading to high-cycle fatigue failure (HCF). HCF is one of the leading causes of engine failure. Therefore, from the perspective of improving engine lifespan and safety, it is essential to employ appropriate vibration reduction techniques during the design phase to lower the probability of blade failure.

[0004] During the operation of aero-engines, axial-flow turbine rotor blades operate in an unsteady flow field, making vibration unavoidable. To reduce the vibration stress on the rotor blades, experimental studies are typically conducted under actual operating conditions. Based on the experimental results, the most suitable operating parameters for the rotor blades are obtained. Therefore, the ability to use experimental analysis methods that closely resemble the actual operating conditions is extremely crucial.

[0005] Currently, existing blade vibration test and analysis devices rely on only one modal exciter to provide excitation force. If the direction of the excitation rod is perpendicular to the rotational tangential of the blade, then it can only provide excitation force in the rotational tangential direction of the blade. The same applies to the rotational radial direction.

[0006] However, in actual operating conditions, the external excitation experienced by the blades is multi-directional, not simply unidirectional. Therefore, a single modal exciter cannot achieve multi-directional excitation. For blade vibration characteristic testing, the commonly used method of using a single modal exciter for unidirectional excitation cannot closely approximate actual operating conditions, making it difficult to test the vibration characteristics of blades under real-world conditions. Utility Model Content

[0007] The purpose of this invention is to solve the problem that existing blade vibration test analysis methods, which use modal exciters to provide only unidirectional excitation to the blade and cannot closely reflect actual working conditions, provide a blade vibration testing device with adjustable excitation angle.

[0008] To achieve the above objectives, the technical solution provided by this utility model is as follows:

[0009] An adjustable excitation angle blade vibration testing device is provided, comprising: a base, a vise, a blade assembly, an excitation block, a rotary table, an excitation module, and a data acquisition module; the vise is fixedly mounted on the base; the blade assembly includes multiple blades, and the number of blades is odd, with the multiple blades vertically spaced on the vise by clamps; the excitation block has an inclined surface and is fixedly mounted on one side of the middle blade in the blade assembly; the rotary table is fixedly mounted on the base; the excitation module includes an excitation rod and a modal exciter, one end of the excitation rod is fixedly connected to the modal exciter, and the other end face is fixedly connected to the inclined surface of the excitation block on the blade; the modal exciter is fixedly mounted on the rotary table and is used to adjust the angle of the excitation rod so that the excitation rod is perpendicular to the inclined surface; it is used to acquire the magnitude of the excitation force applied to the blade by the modal exciter and to obtain the vibration time-domain response of the blade.

[0010] Furthermore, the blade vibration testing device also includes a data analysis and storage module, which is connected to both the data acquisition module and the excitation module to analyze the experimental data.

[0011] Furthermore, the vise is fixedly mounted on the base using fixing bolts; the rotary table is also fixedly mounted on the base using fixing bolts.

[0012] Furthermore, the top surface of the base is provided with multiple inverted T-shaped grooves for placing fixing bolts.

[0013] Furthermore, there are multiple excitation blocks, and the inclination angles of the inclined surfaces of the multiple excitation blocks are different from each other.

[0014] Furthermore, the rotary table includes an adjustment knob, a worm gear rotary table, and a worm gear meshing with the worm gear rotary table. The modal exciter is fixedly installed on the worm gear rotary table, and the adjustment knob is fixedly installed on one end of the worm gear to drive the worm gear rotary table to rotate.

[0015] Furthermore, the data acquisition module includes a force sensor connected between the excitation rod and the modal exciter, an acceleration sensor fixed on the blade, and a data acquisition instrument. Both the force sensor and the acceleration sensor are connected to the data acquisition instrument. The force sensor is used to acquire the magnitude of the excitation force applied to the blade by the modal exciter, and the acceleration sensor is used to acquire the vibration time-domain response of the blade.

[0016] Furthermore, the excitation module also includes a controller and a power amplifier. The controller is connected to the data analysis and storage module and the power amplifier, respectively. The power amplifier is connected to the modal exciter and is used to drive the modal exciter to generate excitation force.

[0017] The advantages of this utility model are:

[0018] 1. The blade vibration device designed in this utility model solves the problem that the existing modal exciter cannot achieve multi-directional excitation of the blade in the blade vibration test. By fixing an excitation block with an inclined surface on the blade, the excitation force applied by the excitation rod connected to it vertically is decomposed into two directions of blade vibration, thereby enabling multi-directional excitation of the blade, which is closer to the actual working conditions.

[0019] 2. The rotary table designed in this utility model is connected to the modal exciter and can change the angle of the excitation rod on the modal exciter so that the excitation rod is perpendicularly connected to the inclined surface of the excitation block. Then, the excitation force provided by the excitation rod can be decomposed into two mutually perpendicular components through orthogonal decomposition. The two components can provide excitation in two directions for the blade. Attached Figure Description

[0020] The features and advantages of this invention will become more readily understood from the following description with reference to the accompanying drawings, which are not drawn to scale and some features are enlarged or reduced to show details of specific parts.

[0021] Figure 1 This is a schematic diagram of the blade vibration testing device in this utility model;

[0022] Figure 2 This is a partial schematic diagram of the contact between the blade, clamp, and vise in this utility model;

[0023] Figure 3 This is a partial schematic diagram of the connection between the excitation block and the blade in this utility model;

[0024] Figure 4 This is a schematic diagram of the excitation block mechanism in this utility model;

[0025] Figure 5 This is a sectional view of the base in this utility model;

[0026] Figure 6 This is a partial schematic diagram of the connection between the excitation module and the blade in this utility model;

[0027] Figure 7 This is a partial schematic diagram of the rotary table in this utility model;

[0028] Figure 8 This is a schematic diagram of the force analysis of the excitation block in this utility model;

[0029] Figure 9 This is a flowchart of the test procedure for the blade vibration testing device in this utility model;

[0030] In the diagram: 1-base; 2-locking knob; 3-viper body; 4-clamping plate; 5-blade; 6-exciter block; 7-exciter rod; 8-force sensor; 9-modal exciter; 10-fixing bolt; 11-rotary table; 12-adjusting knob; 13-fastening bolt; 14-worm gear rotary table; 15-worm. Detailed Implementation

[0031] The present invention will now be described in detail with reference to the accompanying drawings and exemplary embodiments thereof. It should be noted that the following detailed description of the present invention is for illustrative purposes only and is not intended to limit the scope of the invention.

[0032] When aero-engine turbine blades are operating, parameters such as the direction of the excitation force, the amplitude of the external excitation, and the initial clearance have a significant impact on the vibration characteristics of the blade 5. If these parameters are not set appropriately, the lifespan of the blade 5 will be greatly affected. To address the problem that existing blade vibration test analyses using modal exciters 9 can only provide unidirectional excitation to the blade 5 and cannot closely approximate actual operating conditions, this invention provides a blade vibration testing device with an adjustable excitation angle. By exciting the middle blade 5 and observing the characteristics of adjacent blades 5, once the motion mechanism of one blade 5 relative to the left and right blades 5 is obtained, the motion mechanism of the remaining blades 5 can be obtained similarly.

[0033] like Figure 1 As shown, a blade vibration testing device with adjustable excitation angle includes: a base 1, a vise, a blade assembly, an excitation block 6, a rotary table 11, an excitation module, and a data acquisition module.

[0034] The vise is fixedly mounted on the base 1. The blade assembly includes multiple blades 5, and the number of blades 5 is odd. Multiple clamping plates 4 are provided, and the multiple blades 5 are fixed to the vise at vertical intervals through the clamping plates 4.

[0035] like Figure 3 , 4 As shown, the exciter 6 has an inclined surface and is fixedly installed on one side of the blade 5 located in the middle of the blade assembly. Both the exciter 6 and the blade 5 are provided with threaded holes, and the exciter 6 is fixed to the blade 5 by fastening bolts 13. The blade 5 on which the exciter 6 is installed has the same number of blades 5 on both sides, and the crowned blades 5 in the whole circle are cyclically symmetrical.

[0036] like Figure 1 , 2 As shown, this example uses three blades 5 as a group for research, and the clamping plate 4 has four blades.

[0037] like Figure 1 , 6As shown in Figure 8, the excitation module includes an excitation rod 7 and a modal exciter 9. One end of the excitation rod 7 is fixedly connected to the modal exciter 9, and the other end face is fixedly connected to the excitation block 6 on the inclined blade 5. The rotary table 11 is fixedly installed on the base 1, and the modal exciter 9 is fixedly installed on the rotary table 11 by fixing bolts 10, which are used to adjust the angle of the excitation rod 7 so that the excitation rod 7 is perpendicular to the inclined plane.

[0038] The data acquisition module is used to acquire the magnitude of the excitation force applied to the blade 5 by the modal exciter 9, and to obtain the vibration time-domain response of the blade 5.

[0039] The blade 5 vibration device designed in this utility model uses a vise fixed to the base 1 by the vise body 3. The blade assembly, consisting of the blade 5 and clamping plate 4, is fixed to the vise by the locking knob 2. The rotating body is fixed to the base 1, and the modal exciter 9, which provides the excitation force, is fixed to the rotary table 11. By rotating the rotary table 11, the angle of the excitation rod 7 on the modal exciter 9 is changed, making the excitation rod 7 perpendicularly connected to the inclined surface of the excitation block 6 on the blade 5. This allows for orthogonal decomposition of the excitation force provided by the excitation rod 7 into two mutually perpendicular components, which can provide excitation in two directions for the blade 5, more closely resembling actual operating conditions. The vibration response of multiple blades 5 is collected using a data acquisition module, and the experimental data is analyzed. This embodiment mainly obtains the component forces from the excitation rod 7 in different directions by adjusting the angle of the excitation block 6, ultimately obtaining the vibration law and vibration reduction characteristics of the blade 5 under two-dimensional vibration. By setting reasonable operating parameters, the vibration stress level of the blade 5 is reduced to within the allowable range, improving the service life of the aero-engine turbine blade 5.

[0040] Blade 5 is made of beryllium copper alloy and coated with a wear-resistant coating. The strength and surface material properties of blade 5 can meet the friction and normal pressure generated by the excitation contact of the excitation rod 7. After the angle is adjusted, the loosening of the locking knob 2 of the vise and the adjustment knob 12 of the rotary table 11 due to error or slight changes in angle will not affect the test results.

[0041] like Figure 1 As shown, in one embodiment, the blade vibration testing device further includes a data analysis and storage module, which is connected to both the data acquisition module and the excitation module 6, for analyzing experimental data. The modal exciter 9 is controlled by the data analysis and storage module, which is specifically a computer. The excitation frequency required for the current test is applied to the excitation block 6 via the excitation rod 7, and then applied to the blade 5 via the excitation block 6. The excitation rod 7 and the excitation block 6 can withstand pressure values ​​within the range of test parameters. The excitation force obtained by the excitation block 6 through the excitation rod 7 during the test is within the range of excitation force that the excitation block 6 can withstand, and the test results will not be affected by strength issues.

[0042] like Figure 1 As shown, the vise is fixedly mounted on the base 1 by fixing bolts 10; the rotary table 11 is mounted on the base 1 by fixing bolts 10. The installation and fixing effect can meet the normal test requirements.

[0043] like Figure 5 As shown, the top surface of the base 1 has multiple inverted T-shaped grooves for placing the fixing bolts 10. This facilitates the tightening of the fixing bolts 10 onto the base 1, thereby securing the vise and the rotating body onto the base 1.

[0044] like Figure 3 , 6 As shown, the excitation block 6 is fixed on the blade 5. Multiple excitation blocks 6 are provided, and the inclination angles of their inclined surfaces are different. During the experiment, multiple excitation blocks 6 of different sizes and inclination angles can be prepared and adjusted in real time according to the experimental requirements. The threaded holes on different excitation blocks 6 that mate with the excitation rod 7 are identical, ensuring that each excitation block 6 can mate with the excitation rod 7, thus facilitating the smooth conduct of the experiment.

[0045] like Figure 7 As shown, the rotary table 11 includes an adjustment knob 12, a worm gear rotary table 14, and a worm 15 meshing with the worm gear rotary table 14. The modal exciter 9 is fixedly mounted on the worm gear rotary table 14, and the adjustment knob 12 is fixedly mounted on one end of the worm 15, used to make the worm 15 drive the worm gear rotary table 14 to rotate. When adjusting the angle of the excitation rod 7, by rotating the adjustment knob 12, the adjustment knob 12 drives the worm 15 to rotate, and the worm gear rotary table 14 meshing with the worm 15 rotates along with the worm 15, so that the modal exciter 9 on the worm gear rotary table 14 rotates, thereby changing the angle of the excitation rod 7, so that it is perpendicularly connected to the inclined surface of the excitation block 6, and the test can be carried out smoothly.

[0046] like Figure 8 As shown, the excitation rod 7 is subjected to the excitation force transmitted from the modal exciter 9. The excitation block 6 and the excitation rod 7 are vertically connected, and the excitation block 6 is subjected to the excitation force F of the excitation rod 7 perpendicular to the contact surface. 激 F 激 Through orthogonal decomposition, two mutually perpendicular component forces F can be obtained. x and F y The two component forces can excite the blade 5 in two directions respectively. Different component forces F can be obtained for the excitation block 6 at different angles. x and F y .

[0047] like Figure 9As shown, the data acquisition module includes a force sensor 8 connected between the excitation rod 7 and the modal exciter 9, an accelerometer fixed to the blade 5, and a data acquisition instrument. Both the force sensor 8 and the accelerometer are connected to the data acquisition instrument. The force sensor 8 is used to acquire the magnitude of the excitation force applied to the blade 5 by the modal exciter 9, and the accelerometer is used to acquire the vibration time-domain response of the blade 5. The force sensor 8, connected to the data acquisition module, can acquire the magnitude of the excitation force on the current excitation rod 7, thereby obtaining the magnitudes of the two excitation force components. It also feeds back the reaction force generated by the blade 5 on the excitation rod 7 during vibration to the modal exciter 9, allowing the computer to acquire the corresponding experimental data. The accelerometer is a triaxial accelerometer. The excitation rod 7 excites the middle blade 5, causing the blades on both sides 5 to vibrate. The triaxial accelerometer collects the vibration response of the blade 5, and finally, the analysis module analyzes the experimental data.

[0048] like Figure 9 As shown, the excitation module also includes a controller and a power amplifier. The controller is connected to the data analysis and storage module and the power amplifier respectively. The power amplifier is connected to the modal exciter 9 and is used to drive the modal exciter 9 to generate excitation force.

[0049] In this invention, a modal exciter 9 is driven by a computer, controller, and power amplifier to generate a certain excitation force. This force is applied to the excitation block 6 via the excitation rod 7 and force sensor 8. The excitation block 6 decomposes the force into two directions on the blade 5, thus subjecting the blade 5 to excitation in two directions. This allows for the determination of the influence of key parameters on the vibration and damping characteristics of the blade 5 system under two-dimensional vibration. Based on this law, the optimal parameters are obtained, thereby improving the service life of the turbine blade 5. A dual-fixing method is used to fix the blade 5. First, the fixing device vise is fixed to the base 1. Then, the clamping plate 4 and the blade 5 are locked in the vise using the locking knob 2. The modal exciter 9 is fixed on a rotary table 11. The rotary table 11 can be adjusted according to the angle between the excitation rod 7 and the excitation block 6. The adjustment knob 12 of the rotary table 11 drives the worm gear 15 to rotate, causing the worm wheel rotary table 14 to rotate, ultimately rotating the exciter to the appropriate position.

[0050] Finally, it should be noted that the features mentioned and / or shown in the above description of exemplary embodiments of the present invention can be combined in the same or similar manner with one or more other embodiments, combined with features in other embodiments, or substituted for corresponding features in other embodiments. These combined or substituted technical solutions should also be considered as included within the protection scope of the present invention.

Claims

1. A blade vibration testing device with adjustable excitation angle, characterized in that, include: Base (1); A vise is fixedly installed on the base (1); The blade assembly includes multiple blades (5), and the number of the blades (5) is odd. The multiple blades (5) are fixed vertically at intervals on the vise by clamps (4). The excitation block (6) has an inclined surface and is fixedly installed on one side of the blade (5) located in the middle of the blade group; A rotary table (11) is fixedly installed on the base (1); The excitation module includes an excitation rod (7) and a modal exciter (9). One end of the excitation rod (7) is fixedly connected to the modal exciter (9), and the other end face is fixedly connected to the inclined surface of the excitation block (6) on the blade (5). The modal exciter (9) is fixedly installed on the rotary table (11) and is used to adjust the angle of the excitation rod (7) so that the excitation rod (7) is perpendicular to the inclined surface. And a data acquisition module, used to acquire the magnitude of the excitation force applied to the blade (5) by the modal exciter (9), and to obtain the vibration time domain response of the blade (5).

2. The blade vibration testing device according to claim 1, characterized in that, The blade vibration testing device also includes a data analysis and storage module, which is connected to the data acquisition module and the excitation module respectively, and is used to analyze the experimental data.

3. The blade vibration testing device according to claim 1 or 2, characterized in that, The vise is fixedly mounted on the base (1) by fixing bolts (10); the rotary table (11) is mounted on the base (1) by fixing bolts (10).

4. The blade vibration testing device according to claim 3, characterized in that, The top surface of the base (1) is provided with multiple "inverted T" shaped grooves for placing the fixing bolts (10).

5. The blade vibration testing device according to claim 1 or 2, characterized in that, The excitation block (6) is provided in multiple ways, and the inclined angles of the inclined surfaces of the multiple excitation blocks (6) are different from each other.

6. The blade vibration testing device according to claim 1 or 2, characterized in that, The rotary table (11) includes an adjustment knob (12), a worm gear rotary table (14), and a worm (15) meshing with the worm gear rotary table (14). The modal exciter (9) is fixedly installed on the worm gear rotary table (14), and the adjustment knob (12) is fixedly installed at one end of the worm (15) to drive the worm gear rotary table (14) to rotate.

7. The blade vibration testing device according to claim 2, characterized in that, The data acquisition module includes a force sensor (8) connected between the excitation rod (7) and the modal exciter (9), an acceleration sensor fixed on the blade (5), and a data acquisition instrument. The force sensor (8) and the acceleration sensor are both connected to the data acquisition instrument. The force sensor (8) is used to acquire the magnitude of the excitation force applied to the blade (5) by the modal exciter (9), and the acceleration sensor is used to acquire the vibration time-domain response of the blade (5).

8. The blade vibration testing device according to claim 7, characterized in that, The excitation module also includes a controller and a power amplifier. The controller is connected to the data analysis and storage module and the power amplifier respectively. The power amplifier is connected to the modal exciter (9) and is used to drive the modal exciter (9) to generate excitation force.

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