Turbine blade crown damping structure vibration characteristic test device and method

Abstract

The invention discloses a turbine blade crown damping structure vibration characteristic test device and method. The device comprises a workbench, a mounting plate, a blade clamp, a first clamping plate, a second clamping plate, a first limiting block, a second limiting block, a first pressure sensor, a second pressure sensor, a pre-tightening module, a vibration exciter, an acceleration sensor and a control module. During working, the positive pressure of the blade crown is adjusted through the pre-tightening module, the excitation force is directly applied to a test piece through the vibration exciter, and feedback data is obtained through the acceleration sensor. The technical problems that the loading force cannot be adjusted, the loading precision is poor or the loading force is easy to attenuate in the prior art are solved; the universality of the whole test device for turbine blades of different specifications is improved; the coupling interference of the loading mechanism on the excitation signal is avoided; the test process and procedure are simplified, and the test preparation time and efficiency are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of aero-engine vibration testing technology, and in particular to a device and method for testing the vibration characteristics of a turbine blade crown damping structure. Background Technology

[0002] Turbine blades are core hot-end components of aero-engines, subjected to high temperatures, high pressures, high centrifugal forces, and complex alternating loads over extended periods. Blade vibration fatigue is a key factor limiting engine reliability and lifespan. To effectively suppress severe blade vibrations and improve overall damping characteristics, blade crown contact damping structures are widely used in engineering design. The performance of this damping structure, particularly its nonlinear characteristics, directly depends on the magnitude of the normal pressure on the blade crown contact surface and the clearance control. Therefore, precise and controllable vibration characteristic experimental studies of blade crown damping structures are crucial for optimizing blade design and improving engine safety margins.

[0003] In existing technologies, testing methods for turbine blade vibration characteristics mainly include traditional cantilever beam excitation, electromagnetic excitation, and annular blade segment tests simulating real-world conditions. However, when the test object changes to a crown-contact damping structure, existing technologies generally reveal limitations in load application and control. Many devices use simplified mechanical bolt fixing or hydraulic loading methods to apply crown normal pressure, which often lacks precise force feedback mechanisms and online adjustment capabilities. Once the device is assembled, the crown normal pressure is fixed; if the pressure value under test conditions needs to be changed, time-consuming disassembly and reassembly are required. This indirect and non-adjustable loading method is not only cumbersome to operate but also makes it difficult to guarantee high accuracy and repeatability of the loading force under different test conditions, thus failing to accurately capture the nonlinear law of damping value change with normal pressure. Furthermore, some test devices rely on indirect displacement or torque estimation for loading force measurement rather than directly sensing the pressure on the crown contact surface, resulting in a lack of necessary accuracy and reliability in the test data.

[0004] Besides the deficiencies in loading control, existing testing equipment also suffers from shortcomings in structural versatility and ease of assembly. Most blade clamp designs lack versatility, requiring significant time and cost to customize specialized clamps for different turbine blade models and tenon types. Furthermore, the base frame lacks flexible adjustment mechanisms, such as a T-slot array capable of multi-dimensional, high-precision positioning, making the alignment and relative position adjustment between the test piece, clamps, and exciter complex and time-consuming. In some cases, the excitation mechanism and loading clamping system are complexly designed and coupled, resulting in low excitation force transmission efficiency and making the test results susceptible to the influence of coupled vibrations within the system.

[0005] In summary, existing devices and methods for testing the vibration characteristics of turbine blade crown damping structures have significant technical shortcomings in achieving precise stepless adjustment of crown normal pressure, real-time load monitoring, and rapid, high-precision assembly of the test system. These shortcomings severely hinder the high-precision, repeatable measurement of damping characteristics under different normal pressure conditions required in the field of aero-engine blade design. Therefore, there is an urgent need for a test device and method with optimized structure, convenient operation, precise control and measurement of crown normal pressure, and efficient excitation to overcome the deficiencies of existing technologies. Summary of the Invention

[0006] The technical problem to be solved by the present invention is that the existing devices and methods for testing the vibration characteristics of turbine blade crown damping structures generally have technical defects such as low loading force adjustment accuracy, inability to monitor and adjust the crown normal pressure in real time, and poor structural versatility. The present invention provides a device and method for testing the vibration characteristics of turbine blade crown damping structures, which can achieve precise control and real-time monitoring of the crown normal pressure.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] A test device for vibration characteristics of a turbine blade crown damping structure includes a worktable, a mounting plate, a blade clamp, first and second clamping plates, first and second limiting blocks, first and second pressure sensors, a preload module, a vibrator, an acceleration sensor, and a control module.

[0009] The workbench is horizontally positioned, and the mounting plate is fixed to the workbench;

[0010] The blade clamp is fixed on the mounting plate, which has M mortises for detachably connecting with the tenons of the turbine blades to be tested; when the M turbine blades to be tested are installed on the blade clamp, the tenons of the M turbine blades to be tested are on the same circumference, the working surfaces of the blade crowns of adjacent turbine blades to be tested cooperate with each other, and the included angle between adjacent turbine blades to be tested is equal to a preset angle threshold, where M is a natural number greater than or equal to 3.

[0011] The mounting plate is symmetrically provided with a first hinge seat and a second hinge seat on both sides of the blade clamp;

[0012] The first and second clamping plates have the same structure, and each has a strip-shaped through groove for the excitation rod of the exciter to pass through. The lower end of the first clamping plate is hinged to the first hinge seat, and the lower end of the second clamping plate is hinged to the second hinge seat, so that the first and second clamping plates can rotate freely on the plane where the M turbine blades to be tested are located.

[0013] The first and second limiting blocks have the same structure and are fixed to the inner walls of the first and second clamping plates, respectively. The first limiting block is used to mate with the outer working surface of the crown of the first turbine blade to be tested, and the second limiting block is used to mate with the outer working surface of the crown of the Mth turbine blade to be tested. When the first limiting block mates with the outer working surface of the crown of the first turbine blade to be tested, and the second limiting block mates with the outer working surface of the crown of the Mth turbine blade to be tested, both the first and second clamping plates are perpendicular to the mounting plate.

[0014] The first and second pressure sensors have the same structure; one end of the first pressure sensor is perpendicularly fixed to the outer wall of the first clamping plate, and is used to measure the pressure applied by the first limiting block to the crown of the first turbine blade to be tested; one end of the second pressure sensor is perpendicularly fixed to the outer wall of the second clamping plate, and is used to measure the pressure applied by the second limiting block to the crown of the Mth turbine blade to be tested.

[0015] The pre-tightening module includes first and second loading bases, first and second loading bolts, and first and second anti-slip screws;

[0016] The first loading base and the second loading base have the same structure and are symmetrically arranged on both sides of the mounting plate. They are both fixed on the worktable and are provided with threaded through holes with the axis parallel to the worktable and through slots for the excitation rod of the vibrator to pass through.

[0017] The first loading bolt is sequentially threaded to the first anti-slip screw and the threaded through hole on the first loading base, and its stud passes through the threaded through hole on the first loading base and abuts against the other end of the first pressure sensor; the second loading bolt is sequentially threaded to the second anti-slip screw and the threaded through hole on the second loading base, and its stud passes through the threaded through hole on the second loading base and abuts against the other end of the second pressure sensor.

[0018] The excitation rod of the exciter is parallel to the worktable and is used to pass through the through slot on the second loading base, the strip through slot on the second clamping plate, and abut against the back of the Mth turbine blade to be tested, so as to output vibration.

[0019] The acceleration sensor is attached to any one of the turbine blades to be tested to obtain its acceleration vibration response signal.

[0020] The control module is electrically connected to the vibrator, the first pressure sensor, the second pressure sensor, and the acceleration sensor, respectively, and is used to control the operation of the vibrator and obtain the sensing data from the first pressure sensor, the second pressure sensor, and the acceleration sensor.

[0021] As a further optimization of the test device for the vibration characteristics of the turbine blade crown damping structure of the present invention, M is set to 3.

[0022] As a further optimization of the test device for vibration characteristics of turbine blade crown damping structure of the present invention, the workbench is provided with a T-shaped slide array, the T-shaped slide array includes a number of first T-shaped slides arranged in parallel at equal intervals and a number of second T-shaped slides arranged in parallel at equal intervals, the first T-shaped slides intersecting each of the second T-shaped slides perpendicularly.

[0023] The mounting plate, the first loading base, and the second loading base are all detachably connected by bolts that cooperate with the T-shaped sliding groove array.

[0024] As a further optimization of the test device for the vibration characteristics of the turbine blade crown damping structure of the present invention, the tenon groove on the blade fixture is a sliding groove for the tenon of the turbine blade to be tested to slide in and out parallel to the worktable; for each tenon groove, the bottom of the mounting plate is provided with at least one threaded blind hole connected to its bottom, and the tenon of the turbine blade to be tested in the tenon groove is fixed or loosened by bolts that cooperate with the threaded blind hole.

[0025] This invention also discloses a test method for the vibration characteristic test device of the turbine blade crown damping structure, comprising the following steps:

[0026] Step 1), mount the M turbine blades to be tested onto the blade fixture;

[0027] Step 2), tighten the first loading bolt and the second loading bolt respectively to apply pressure to the blade crowns of the 1st and Mth turbine blades to be tested;

[0028] Step 3), record the pressure values ​​of the first pressure sensor and the second pressure sensor;

[0029] Step 4), tighten the first anti-slip nut and the second anti-slip nut so that they abut against the first loading base and the second loading base respectively, to complete the loading lock required for the test condition;

[0030] Step 5), the control module drives the exciter to work, applies excitation force to the Mth turbine blade under test through its excitation rod, and records the vibration response data fed back by the acceleration sensor to complete the vibration characteristic test.

[0031] Compared with the prior art, the present invention, employing the above technical solution, has the following technical effects:

[0032] 1. This invention enables precise, continuous, stepless adjustment and real-time monitoring of the magnitude of the positive pressure on the leaf crown, solving the technical problems of non-adjustable loading force, poor loading accuracy, or easy attenuation of loading force in the prior art;

[0033] 2. The T-slot array on the workbench of this invention, combined with T-bolts, allows for flexible adjustment of the relative positions of the blade clamp, the first loading base, and the second loading base, thereby improving the versatility of the entire test device for turbine blades of different specifications.

[0034] 3. In this invention, the excitation rod applies the excitation force directly to the test piece through a pre-set through hole penetrating the loading base and the loading clamp, ensuring efficient and direct transmission of the excitation force, avoiding coupling interference of the loading mechanism to the excitation signal, and improving the signal-to-noise ratio and accuracy of vibration measurement;

[0035] 4. This invention enables in-situ adjustment and real-time monitoring of the loading force, simplifies the test process and procedures, and significantly improves test preparation time and efficiency. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of the present invention;

[0037] Figure 2 This is a schematic diagram of the structure of the blade clamp and mounting plate in this invention.

[0038] Figure 3 This is a schematic diagram of the workbench structure in this invention.

[0039] In the figure, 1-workbench, 2-mounting plate, 3-blade clamp, 4-first clamping plate, 5-second clamping plate, 6-second limiting block, 7-first loading base, 8-second loading base, 9-first loading bolt, 10-first anti-slip screw, 11-turbine blade to be tested, 12-vibrator, 13-first hinge seat, 14-second hinge seat. Detailed Implementation

[0040] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings:

[0041] This invention can be implemented in many different forms and should not be considered limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully express the scope of the invention to those skilled in the art. In the drawings, components are enlarged for clarity.

[0042] It should be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, and / or parts, these elements, components, and / or parts are not limited by these terms. These terms are merely used to distinguish elements, components, and / or parts from one another. Therefore, the first element, component, and / or part discussed below may be a second element, component, or part without departing from the teachings of this invention.

[0043] In the description of this invention, it should be understood that the terms "horizontal," "vertical," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and should not be construed as limiting this invention; the terms "installation," "connection," "fixing," etc., should be interpreted broadly, for example, they can refer to a fixed connection, a detachable connection, or an integral connection, they can refer to a direct connection, an indirect connection through an intermediate medium, or a connection within two components; for those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0044] like Figure 1 As shown, the present invention discloses a test device for the vibration characteristics of a turbine blade crown damping structure, including a workbench, a mounting plate, a blade clamp, first and second clamping plates, first and second limiting blocks, first and second pressure sensors, a preload module, a vibrator, an acceleration sensor, and a control module.

[0045] The workbench is horizontally positioned, and the mounting plate is fixed to the workbench;

[0046] like Figure 2 As shown, the blade clamp is fixed on the mounting plate, which has M mortises for detachably connecting with the tenons of the turbine blades to be tested; when the M turbine blades to be tested are installed on the blade clamp, the tenons of the M turbine blades to be tested are on the same circumference, the working surfaces of the blade crowns of adjacent turbine blades to be tested cooperate with each other, and the included angle between adjacent turbine blades to be tested is equal to a preset angle threshold, where M is a natural number greater than or equal to 3;

[0047] The mounting plate is symmetrically provided with a first hinge seat and a second hinge seat on both sides of the blade clamp;

[0048] The first and second clamping plates have the same structure, and each has a strip-shaped through groove for the excitation rod of the exciter to pass through. The lower end of the first clamping plate is hinged to the first hinge seat, and the lower end of the second clamping plate is hinged to the second hinge seat, so that the first and second clamping plates can rotate freely on the plane where the M turbine blades to be tested are located.

[0049] The first and second limiting blocks have the same structure and are fixed to the inner walls of the first and second clamping plates, respectively. The first limiting block is used to mate with the outer working surface of the crown of the first turbine blade to be tested, and the second limiting block is used to mate with the outer working surface of the crown of the Mth turbine blade to be tested. When the first limiting block mates with the outer working surface of the crown of the first turbine blade to be tested, and the second limiting block mates with the outer working surface of the crown of the Mth turbine blade to be tested, both the first and second clamping plates are perpendicular to the mounting plate.

[0050] The first and second pressure sensors have the same structure; one end of the first pressure sensor is perpendicularly fixed to the outer wall of the first clamping plate, and is used to measure the pressure applied by the first limiting block to the crown of the first turbine blade to be tested; one end of the second pressure sensor is perpendicularly fixed to the outer wall of the second clamping plate, and is used to measure the pressure applied by the second limiting block to the crown of the Mth turbine blade to be tested.

[0051] The pre-tightening module includes first and second loading bases, first and second loading bolts, and first and second anti-slip screws;

[0052] The first loading base and the second loading base have the same structure and are symmetrically arranged on both sides of the mounting plate. They are both fixed on the worktable and are provided with threaded through holes with the axis parallel to the worktable and through slots for the excitation rod of the vibrator to pass through.

[0053] The first loading bolt is sequentially threaded to the first anti-slip screw and the threaded through hole on the first loading base, and its stud passes through the threaded through hole on the first loading base and abuts against the other end of the first pressure sensor; the second loading bolt is sequentially threaded to the second anti-slip screw and the threaded through hole on the second loading base, and its stud passes through the threaded through hole on the second loading base and abuts against the other end of the second pressure sensor.

[0054] The excitation rod of the exciter is parallel to the worktable and is used to pass through the through slot on the second loading base, the strip through slot on the second clamping plate, and abut against the back of the Mth turbine blade to be tested, so as to output vibration.

[0055] The acceleration sensor is attached to any one of the turbine blades to be tested to obtain its acceleration vibration response signal.

[0056] The control module is electrically connected to the vibrator, the first pressure sensor, the second pressure sensor, and the acceleration sensor, respectively, and is used to control the operation of the vibrator and obtain the sensing data from the first pressure sensor, the second pressure sensor, and the acceleration sensor.

[0057] M is preferred to be 3.

[0058] like Figure 3 As shown, the workbench is provided with a T-shaped slide array, which includes a number of first T-shaped slides arranged in parallel at equal intervals and a number of second T-shaped slides arranged in parallel at equal intervals. The first T-shaped slides intersect each of the second T-shaped slides perpendicularly.

[0059] The mounting plate, the first loading base, and the second loading base are all detachably connected by bolts that cooperate with the T-shaped sliding groove array.

[0060] The tenon groove on the blade fixture preferably adopts a sliding groove for the tenon of the turbine blade to be tested to slide in and out parallel to the worktable; for each tenon groove, the bottom of the mounting plate is provided with at least one threaded blind hole connected to its bottom, and the tenon of the turbine blade to be tested in the tenon groove is fixed or loosened by bolts that cooperate with the threaded blind hole.

[0061] This invention also discloses a test method for the vibration characteristic test device of the turbine blade crown damping structure, comprising the following steps:

[0062] Step 1), mount the M turbine blades to be tested onto the blade fixture;

[0063] Step 2), tighten the first loading bolt and the second loading bolt respectively to apply pressure to the blade crowns of the 1st and Mth turbine blades to be tested;

[0064] Step 3), record the pressure values ​​of the first pressure sensor and the second pressure sensor;

[0065] Step 4), tighten the first anti-slip nut and the second anti-slip nut so that they abut against the first loading base and the second loading base respectively, to complete the loading lock required for the test condition;

[0066] Step 5), the control module drives the exciter to work, applies excitation force to the Mth turbine blade under test through its excitation rod, and records the vibration response data fed back by the acceleration sensor to complete the vibration characteristic test.

[0067] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0068] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A test device for the vibration characteristics of a turbine blade crown damping structure, characterized in that, It includes a worktable, mounting plate, blade clamp, first and second clamping plates, first and second limit blocks, first and second pressure sensors, pre-tightening module, vibrator, acceleration sensor and control module; The workbench is horizontally positioned, and the mounting plate is fixed to the workbench; The blade clamp is fixed on the mounting plate, which has M mortises for detachably connecting with the tenons of the turbine blades to be tested; when the M turbine blades to be tested are installed on the blade clamp, the tenons of the M turbine blades to be tested are on the same circumference, the working surfaces of the blade crowns of adjacent turbine blades to be tested cooperate with each other, and the included angle between adjacent turbine blades to be tested is equal to a preset angle threshold, where M is a natural number greater than or equal to 3. The mounting plate is symmetrically provided with a first hinge seat and a second hinge seat on both sides of the blade clamp; The first and second clamping plates have the same structure, and each has a strip-shaped through groove for the excitation rod of the exciter to pass through. The lower end of the first clamping plate is hinged to the first hinge seat, and the lower end of the second clamping plate is hinged to the second hinge seat, so that the first and second clamping plates can rotate freely on the plane where the M turbine blades to be tested are located. The first and second limiting blocks have the same structure and are fixed to the inner walls of the first and second clamping plates, respectively. The first limiting block is used to mate with the outer working surface of the crown of the first turbine blade to be tested, and the second limiting block is used to mate with the outer working surface of the crown of the Mth turbine blade to be tested. When the first limiting block mates with the outer working surface of the crown of the first turbine blade to be tested, and the second limiting block mates with the outer working surface of the crown of the Mth turbine blade to be tested, both the first and second clamping plates are perpendicular to the mounting plate. The first and second pressure sensors have the same structure; one end of the first pressure sensor is perpendicularly fixed to the outer wall of the first clamping plate, and is used to measure the pressure applied by the first limiting block to the crown of the first turbine blade to be tested; one end of the second pressure sensor is perpendicularly fixed to the outer wall of the second clamping plate, and is used to measure the pressure applied by the second limiting block to the crown of the Mth turbine blade to be tested. The pre-tightening module includes first and second loading bases, first and second loading bolts, and first and second anti-slip screws; The first loading base and the second loading base have the same structure and are symmetrically arranged on both sides of the mounting plate. They are both fixed on the worktable and are provided with threaded through holes with the axis parallel to the worktable and through slots for the excitation rod of the vibrator to pass through. The first loading bolt is sequentially threaded to the first anti-slip screw and the threaded through hole on the first loading base, and its stud passes through the threaded through hole on the first loading base and abuts against the other end of the first pressure sensor; the second loading bolt is sequentially threaded to the second anti-slip screw and the threaded through hole on the second loading base, and its stud passes through the threaded through hole on the second loading base and abuts against the other end of the second pressure sensor. The excitation rod of the exciter is parallel to the worktable and is used to pass through the through slot on the second loading base, the strip through slot on the second clamping plate, and abut against the back of the Mth turbine blade to be tested, so as to output vibration. The acceleration sensor is attached to any one of the turbine blades to be tested to obtain its acceleration vibration response signal. The control module is electrically connected to the vibrator, the first pressure sensor, the second pressure sensor, and the acceleration sensor, respectively, and is used to control the operation of the vibrator and obtain the sensing data from the first pressure sensor, the second pressure sensor, and the acceleration sensor.

2. The test device for vibration characteristics of turbine blade crown damping structure according to claim 1, characterized in that, M is set to 3.

3. The test device for vibration characteristics of turbine blade crown damping structure according to claim 1, characterized in that, The workbench is provided with a T-shaped slide array, which includes a number of first T-shaped slides arranged in parallel at equal intervals and a number of second T-shaped slides arranged in parallel at equal intervals. The first T-shaped slides intersect each of the second T-shaped slides perpendicularly. The mounting plate, the first loading base, and the second loading base are all detachably connected by bolts that cooperate with the T-shaped sliding groove array.

4. The test device for vibration characteristics of turbine blade crown damping structure according to claim 1, characterized in that, The tenon groove on the blade fixture is a sliding groove for the tenon of the turbine blade to be tested to slide in and out parallel to the worktable; for each tenon groove, the bottom of the mounting plate is provided with at least one threaded blind hole connected to its bottom, and the tenon of the turbine blade to be tested in the tenon groove is fixed or loosened by bolts that cooperate with the threaded blind hole.

5. The test method based on the turbine blade crown damping structure vibration characteristic test device according to claim 1, characterized in that, Includes the following steps: Step 1), mount the M turbine blades to be tested onto the blade fixture; Step 2), tighten the first loading bolt and the second loading bolt respectively to apply pressure to the blade crowns of the 1st and Mth turbine blades to be tested; Step 3), record the pressure values ​​of the first pressure sensor and the second pressure sensor; Step 4), tighten the first anti-slip nut and the second anti-slip nut so that they abut against the first loading base and the second loading base respectively, to complete the loading lock required for the test condition; Step 5), the control module drives the exciter to work, applies excitation force to the Mth turbine blade under test through its excitation rod, and records the vibration response data fed back by the acceleration sensor to complete the vibration characteristic test.

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