Device and method for testing vibration characteristics of turbine damping blade of gas turbine under multi-load loading condition

Abstract

The invention discloses a gas turbine damping blade vibration characteristic testing device and method under a multi-load loading condition, an electric heating furnace is internally provided with an induction heating coil, and a damping blade test piece is arranged in the induction heating coil; a tenon tooth fixture is mounted on the tenon tooth fixing base, and a tenon tooth part of the damping blade test piece is mounted in the tenon tooth fixture; a loading top block is mounted on the positive pressure loading disc and is in contact with a damping structure of the damping blade test piece; a modal vibration exciter is installed on the vibration excitation support, one end of the large-rigidity-ratio vibration excitation rod is connected with the modal vibration exciter, and the other end of the large-rigidity-ratio vibration excitation rod is connected with the blade body surface of a damping blade test piece. And the optical head is connected with a laser controller and is over against the furnace wall of the electric heating furnace. The change rule of the blade vibration characteristic along with each load factor can be obtained, and the accuracy of the damping blade vibration characteristic analysis method is verified.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of vibration test of turbomachinery, and relates to a device and method for testing vibration characteristics of a gas turbine turbomachinery damping blade under a multi-load loading condition. BACKGROUND

[0002] As the core power equipment in the fields of power, industrial manufacturing and ship propulsion, the safety and reliability of the gas turbine is directly related to the economic security. The damage of the turbine blade is the primary cause of the failure of such rotating machinery, and vibration fatigue is the main mechanism leading to the damage of the blade. In order to improve the vibration safety of the blade, a damping structure is usually introduced into the turbine blade, and the vibration energy is dissipated through the dry friction between the structural members, so as to effectively reduce the vibration stress level of the blade.

[0003] In order to accurately obtain the vibration level of the turbine damping blade, on the one hand, the vibration characteristics can be predicted by a numerical solution method, and on the other hand, the accuracy of the numerical calculation needs to be verified by designing and carrying out vibration characteristic tests. The vibration characteristic test of the turbine damping blade is usually carried out at room temperature, and the vibration characteristic test results are obtained by loading the blade. However, the turbine blade of the gas turbine will bear high-temperature thermal load, so that the overall material performance of the damping blade changes, and then the working mechanism and damping effect of the damping structure are affected, which threatens the fatigue resistance and reliability of the blade. At present, there are relatively few damping blade vibration test platforms considering multiple load factors such as thermal load, and there is a lack of relevant test data of the vibration response of the blade and the friction characteristics of the damping structure under heating conditions, which restricts the development of vibration test research on the damping blade under simulated real environment. SUMMARY

[0004] The present application aims to overcome the shortcomings of the prior art, and provides a device and method for testing vibration characteristics of a gas turbine turbomachinery damping blade under a multi-load loading condition, which can obtain the variation law of the blade vibration characteristics with each load factor and verify the accuracy of the damping blade vibration characteristic analysis method.

[0005] To achieve the above-mentioned purpose, the following technical solutions are adopted: A device for testing vibration characteristics of a gas turbine turbomachinery damping blade under a multi-load loading condition, comprising an electric heating furnace, a damping blade test piece, a tenon-tooth fixed base, a positive pressure loading disc, an excitation support, a large-stiffness-ratio excitation rod and an optical head; The electric heating furnace is internally provided with an induction heating coil, and the damping blade test piece is arranged in the induction heating coil; A tenon-tooth clamp is mounted on the tenon-tooth fixed base, and the tenon-tooth part of the damping blade test piece is mounted in the tenon-tooth clamp; A loading top block is installed on the positive pressure loading plate, and the loading top block is in contact with the damping structure of the damping blade test piece; A modal exciter is installed on the vibration support. One end of the high stiffness ratio exciter rod is connected to the modal exciter, and the other end is connected to the blade surface of the damped blade test piece. The optical head is connected to a laser controller and is positioned directly opposite the furnace wall of the electric heating furnace.

[0006] Preferably, the top of the electric heating furnace is sealed by a sealing flange; a viewing window is provided on the furnace wall of the electric heating furnace.

[0007] Preferably, the furnace wall of the electric heating furnace is further provided with a positive pressure loading slot, a vibration loading slot, and a tenon fixing slot; the loading top block passes through the positive pressure loading slot and contacts the damping structure of the damping blade test piece; the high stiffness ratio excitation rod passes through the vibration loading slot and connects to the damping blade test piece; the tenon clamp passes through the tenon fixing slot and is installed on the tenon fixing base.

[0008] Preferably, it also includes a loading plate bracket, on which the positive pressure loading plate is mounted; the positive pressure loading plate is provided with a loading pull ring, which is connected by a steel wire rope, and a dynamic force sensor is connected in series on the steel wire rope.

[0009] Preferably, the excitation support is provided with an exciter rotation guide groove centered on the axis of the damped blade test piece, and the position of the modal exciter along the exciter rotation guide groove is adjustable; a dynamic force sensor is provided on the high stiffness ratio excitation rod, and the dynamic force sensor is located between the modal exciter and the damped blade test piece.

[0010] Preferably, a hydraulic jack is provided on the tenon fixing base, and the output end of the hydraulic jack abuts against the tenon clamp.

[0011] Preferably, the high stiffness ratio excitation rod is a variable cross-section structure, in which the cross-sectional dimensions of the middle section are smaller than those of its two ends.

[0012] Preferably, it also includes a temperature control cabinet and a thermocouple, with the temperature control cabinet connected to the induction heating coil, and the temperature measuring end of the thermocouple extending into the electric heating furnace and connected to the temperature control cabinet.

[0013] A method for testing the vibration characteristics of a gas turbine damping blade under multiple load conditions includes the following steps: Install the tenon part of the damping blade test piece in the tenon clamp, and fix the tenon clamp on the tenon fixing base; A normal pressure load is applied to the damping structure of the damping blade test specimen by means of the loading top block on the normal pressure loading plate; One end of the high stiffness ratio excitation rod is fixed to the blade surface of the damped blade test specimen; Put the damping blade test piece in the induction heating coil of the electric heating furnace, start the induction heating coil to heat the damping blade test piece to the preset temperature; A modal exciter is used to apply a simple harmonic exciting force to the damping blade test piece through a large stiffness ratio excitation rod; An optical head and a laser controller are used to collect the vibration response signal of the damping blade test piece.

[0014] Preferably, the method further comprises the following steps: The excitation frequency of the simple harmonic exciting force is changed to perform sweep frequency measurement, and the vibration response signal under different excitation frequencies is obtained; The amplitude of the simple harmonic exciting force is changed, and the sweep frequency measurement is repeated to obtain the vibration response signal under different excitation force amplitudes; The size of the positive pressure load is changed, and the sweep frequency measurement is repeated to obtain the vibration response signal under different positive pressure loads; The value of the preset temperature is changed, and the sweep frequency measurement is repeated to obtain the vibration response signal under different temperatures.

[0015] Compared with the prior art, the present application has the following beneficial effects: The present application solves the technical problem that the prior art cannot accurately simulate the multi-physical field coupling of the gas turbine turbine blade under the real working environment in static test by integrating electric heating, tenon tooth fixation, positive pressure loading and excitation force loading. First, a controllable high temperature environment is constructed by using high frequency induction heating principle, which truly reproduces the thermal load borne by the blade; second, static prestress and positive pressure are applied to the blade tenon and damping structure respectively by using hydraulic pre-tightening and torque balance principle, which equivalently simulates the fixed constraint and damping contact pressure of the blade under high speed rotation due to centrifugal force; third, dynamic excitation load is applied by combining controllable modal exciter, which simulates aerodynamic excitation. Finally, non-contact laser vibration measurement technology is used to penetrate the high temperature environment for high precision vibration response measurement. The design of synchronous coupling loading and accurate measurement of multiple loads enables the present application to obtain accurate experimental data of blade vibration and damping characteristics under near real working conditions, which provides reliable test basis for verifying numerical analysis model and optimizing blade damping design, thereby significantly improving the operation safety and reliability of the gas turbine. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The present application is a load loading condition gas turbine turbine damping blade vibration characteristic testing device structure schematic diagram; Figure 2 The present application is an electric heating device structure schematic diagram, which is a three-dimensional model and a sectional view; Figure 3 The present application is a positive pressure equivalent loading and measuring device schematic diagram; Figure 4 Figure 1 is a schematic diagram of a tenon fixture according to the present application; Figure 5 Figure 2 is a schematic diagram of an excitation force equivalent loading and measuring device according to the present application; Figure 6 Figure 3 is a schematic diagram of an excitation and measuring device according to the present application; Figure 7 Figure 4 is a flow chart of a method for testing the vibration characteristics of a gas turbine turbine damping blade under a multi-load loading condition according to the present application; Figure 8 Figure 5 is a flow chart of a test measurement signal processing procedure according to the present application.

[0017] Wherein: 1 - laser controller; 2 - optical head; 3 - positive pressure loading disc; 4 - electric heating furnace; 5 - induction heating coil; 6 - visual window; 7 - damping blade test piece; 8 - tenon clamp; 9 - tenon fixing base; 10 - multi-channel data acquisition device; 11 - thermocouple; 12 - loading top block; 13 - large stiffness ratio excitation rod; 14 - hydraulic jack; 15 - dynamic force sensor; 16 - modal exciter; 17 - high-performance computer; 18 - signal generator; 19 - power amplifier; 20 - temperature control cabinet; 21 - positive pressure loading slot; 22 - sealing flange; 23 - constant temperature zone; 24 - excitation force loading slot; 25 - tenon fixing slot; 26 - loading disc bracket; 27 - loading disc rotating guide groove; 28 - top block rotating guide groove; 29 - loading pull ring; 30 - steel wire rope; 31 - exciter rotating guide groove; 32 - excitation support. DETAILED DESCRIPTION

[0018] Embodiments of the present application are described in detail below with reference to the attached drawing figures, wherein the same or like reference numerals and letters in the drawing figures and the following description denote the same or like elements or components. The embodiments described below are exemplary and not intended to be limiting of the scope of the present application, as defined by the appended claims.

[0019] In the description of the present application, it is to be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements indicated thereby must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated thereby. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically defined.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terms "install", "connect with", "connect" should be understood broadly, for example, can be fixed connection, can also be detachable connection, or integral connection; can be mechanical connection, can also be electrical connection or can communicate with each other; can be directly connected, can also be indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship between two elements. The term "and / or" used herein includes any and all combinations of one or more related listed items. The specific meaning of the above terms in the present application can be understood by the person skilled in the art according to the specific circumstances. The terms used in the specification of the present application are only for the purpose of describing the specific embodiments, and are not intended to limit the present application.

[0021] In the present application, unless otherwise specifically defined and limited, the "upper" or "lower" of the first feature to the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the "upper", "above" and "on" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The "under", "below" and "under" of the first feature to the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0022] The following disclosure provides many different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0023] like Figure 1 As shown, the device for testing the vibration characteristics of a gas turbine damping blade under multiple load conditions according to the present invention mainly includes: The electric heating device includes a detachable electric heating furnace 4, an induction heating coil 5, a thermocouple 11, a temperature control cabinet 20, etc. By placing the damping blade test piece 7 in the induction heating coil 5 of the electric heating device, the overall damping blade test piece 7 is heated and the working environment is simulated. The tenon fixing device includes a tenon clamp 8, a tenon fixing base 9, a hydraulic jack 14, etc. By installing the blade tenon in the tenon clamp 8, the hydraulic jack 14 is used to apply a prestress load to the tenon, and the blade is fixed on the base as a whole.

[0024] The positive pressure equivalent loading and measurement device includes a positive pressure loading disk 3, a loading top block 12, a loading pull ring 29, a steel wire rope 30, a dynamic force sensor 15, etc., to apply a positive pressure load to the blade damping structure such as the shroud, so that the loading top block 12 on the loading disk 3 comes into contact with the blade damping structure, and the positive pressure load is changed by adjusting the tension of the steel wire ropes 30 on both sides.

[0025] The excitation force equivalent loading and measurement device includes a modal exciter 16, a high stiffness ratio excitation rod 13, etc., and applies a single-point excitation load of a certain frequency and amplitude to the blade surface through the modal exciter 16.

[0026] The laser vibration measurement device includes a laser controller 1 and an optical head 2. The optical head 2 transmits and receives vibration measurement signals to the laser controller 1, thereby realizing the real-time acquisition of blade vibration response signals.

[0027] The data acquisition and processing device includes a multi-channel data acquisition unit 10 and a high-performance computer 17. The multi-channel data acquisition unit 10 decodes and processes the excitation force signal, normal pressure signal and response signal, and can realize vibration simulation tests of various damper contact surface normal pressure load, excitation frequency and excitation force conditions. It can obtain resonance response curves of measuring points at different blade heights, study the vibration damping characteristics of the blade, and verify the accuracy of the vibration analysis method.

[0028] This invention enables the construction and adjustment of the working environment temperature of the entire blade from room temperature to 800°C by building an electric heating device based on high-frequency induction heating. Figure 2 A schematic diagram of the electric heating device is provided, where a is a 3D model and b is a sectional view. It mainly consists of a detachable electric heating furnace 4, a sealing flange 22, an induction heating coil 5, and a thermocouple 11, used to construct a high-temperature, sealed working environment for the damping blades. A vertical electric heating furnace 4 with a suitable heating zone length is selected based on the blade length. The furnace body adopts a concentric, detachable cylindrical design with an inner cylinder, insulation layer, and outer wall. The furnace body and control cabinet are separable, and the mounting base at the bottom of the furnace body is fixed to the foundation with bolts. The electric heating furnace 4 is opened, and the entire damping blade test piece 7 and part of the tenon clamp 8 are placed into the induction heating coil 5. The heating temperature is adjusted by the temperature control cabinet 20 to achieve uniform loading of the coil current intensity, generating an induced current to heat the blades, ultimately creating a stable temperature field inside the furnace. A thermocouple temperature sensor is installed from the top of the electric heating furnace 4 to the constant temperature zone 23 and connected to the temperature control cabinet 20 to read the furnace temperature in real time. The top of the electric heating furnace 4 is sealed with a flange to isolate air, and the middle layer is filled with insulation material. Two positive pressure loading slots 21 are provided at the height of the shroud for installing a positive pressure application device to apply a positive pressure load to the shroud. An excitation force loading slot 24 is provided on the excitation application side for applying an excitation load to the blades. A tenon fixing slot 25 is provided at the bottom for mounting the tenon clamp 8 on the tenon fixing base 9. Viewing windows 6 are provided at three different heights corresponding to the blades on the furnace body. These windows are made of high-transmittance, high-temperature resistant optical quartz glass to isolate the high-temperature environment and enable the laser vibrometer to emit and receive optical signals. The visible light transmittance reaches over 95%, and the thickness is only 1mm, reducing laser refraction loss. The openings in contact with air are filled and sealed with high-temperature resistant heat-insulating material.

[0029] A temperature control cabinet 20, connected to the induction heating coil 5, is installed outside the electric heating device to load and adjust the thermal load on the blades. By adjusting the temperature setpoint of the temperature control cabinet 20 via a knob, the induction heating coil 5 inside the electric heating furnace 4 starts working, generating an induced current to heat the blades. A thermocouple 11 is inserted near the blades to measure the temperature in real time, and the reading is displayed on the panel of the temperature control cabinet 20, with the indicator light showing green. When the measured value reaches the set temperature, the switch automatically disconnects, the coil stops heating, and the furnace temperature fluctuates around the set value until it finally reaches a stable value, at which point the indicator light shows red. The temperature measured by the thermocouple when the furnace temperature reaches a steady state is the blade temperature.

[0030] This invention establishes a normal pressure equivalent loading and measurement device, a tenon fixing device, and an excitation force loading device suitable for blade damping structure forms, to simulate the centrifugal force and excitation force load that the actual blade is subjected to under rotation conditions, and realizes the equivalent and accurate simulation of the load applied to the rotating state by static test.

[0031] Taking the blade damping shroud as an example, Figure 3 A schematic diagram is provided showing the application of a positive pressure load to the contact surface of the blade sheath using a positive pressure equivalent loading and measuring device. This includes a loading disc bracket 26, a positive pressure loading disc 3, a loading top block 12, a loading pull ring 29, a steel wire rope 30, and a dynamic force sensor 15. Based on the height of the blade sheath, through holes are opened at corresponding height positions in the electric heating furnace 4 to apply positive pressure to both sides of the sheath. Four rotating guide grooves 28 are provided on the loading disc to fix the loading top blocks 12. The loading top blocks 12 on opposite sides pass through the through holes and contact both sides of the blade sheath. The loading pull ring 29 is bolted into the positive pressure loading disc 3 and connected to the steel wire rope 30. The dynamic force sensor 15 is connected to the middle of the steel wire rope 30. By simultaneously rotating the handles on both sides to tighten or loosen the steel wire rope 30, the rotation angle of the positive pressure loading disc 3 is adjusted, thereby changing the magnitude of the tension applied by the dynamic force sensor 15. The loading pull rings 29 on both sides apply tension to the positive pressure loading disc 3, causing the loading top block 12 to contact the blade sheath and generate a positive pressure load. The contact area between the loading top block 12 and the shroud is a circular surface to simulate the frictional damping characteristics of a spherical-plane micro-slip model. The normal pressure borne between the contact surfaces of the blade shroud... N 0, can be achieved by the tensile force borne by the loading disk. F and the corresponding lever arm L and the positive pressure arm of the belt d To calculate this, based on the principle of torque balance, the normal force acting on the damping structure is converted into a tensile force for application, achieving an equivalent loading of the normal force on the damping structure. The following equation can be established:

[0032] in, N 0 represents the normal pressure load (N) at the contact surface of the shroud. F 0 represents the tensile force (N) on the outer side of the positive pressure loading disk of the surrounding belt; L The lever arm (mm) of the tensile force on the outer side of the positive pressure loading plate of the belt; d The positive pressure arm of the belt is shown in mm. After adjustment, the rotating guide groove 27 of the loading plate and the horizontal groove on the bracket are connected by bolts to fix the currently adjusted rotation angle. During adjustment, ensure that the readings of the sensors on both sides are the same to ensure that the applied tension at both ends is the same. The four through holes of the electric heating furnace are filled with heat insulation material to maintain the high temperature environment inside the furnace.

[0033] Figure 4A schematic diagram of the tenon tooth fixing device is provided, mainly including a tenon tooth clamp 8, a tenon tooth fixing base 9, and a hydraulic jack 14. The main objective is to fully constrain the tenon tooth in all directions. Based on the tenon tooth groove profile of the three-tooth fir tree-shaped blade, a fir tree-shaped tenon tooth clamp 8 is designed and manufactured to perfectly match it, thereby simulating the tooth surface contact during tenon tooth and groove assembly. During the experiment, the blade is clamped in the fir tree-shaped tenon tooth clamp 8, ensuring that the tenon tooth portion of the blade is subjected to a uniform clamping force. Through the close contact between the clamp and the blade tooth surface, the circumferential and radial displacement of the blade under vibration is effectively limited. A groove is provided on the tenon tooth fixing base 9, into which the tenon tooth clamping block can be installed radially from below. The axial and radial displacement constraints on the tenon tooth are further applied by the action of the jack.

[0034] Figure 5 A schematic diagram of the equivalent loading and measurement device for excitation force is provided, including a modal exciter 16, a high stiffness ratio excitation rod 13, a dynamic force sensor 15, and an excitation support 32. Its main function is to apply a stable harmonic excitation force load of a certain amplitude and frequency to the blade. The excitation support 32 has a rotating guide groove 31 centered on the blade axis, allowing adjustment of the position and angle of the applied excitation force. The high stiffness ratio excitation rod 13 has a variable cross-section design; one end is connected to the output end of the modal exciter 16, and the other end passes through a slot in the electric heating furnace 4 and is fixed to the blade excitation point with high-temperature sealant. The axial to lateral stiffness ratio of the high stiffness ratio excitation rod 13 is >>100, effectively absorbing the tangential load generated by the excitation equipment through its own flexibility, thereby reducing the nonlinear excitation effect on the blade caused by the additional constraints of the connecting rod. A dynamic force sensor 15 is also installed on the side of the connecting rod near the exciter output end to accurately measure and monitor the actual excitation force on the blade in real time.

[0035] Figure 6 A schematic diagram of the vibration measurement device is provided. Under high-temperature testing conditions, the damping blades are heated within a sealed electric heating device. Therefore, direct measurement of the vibration response using a room-temperature eddy current displacement sensor is not possible. A laser vibrometer is used for non-contact measurement of the vibration response of the high-temperature damping blades. This laser vibrometer consists of an optical head 2 and a laser controller 1. The optical head 2 is mounted on a tripod and connected to the laser controller. The measurement range and filter are set using the touchscreen on the laser controller 1. The optical head 2 is then aligned with the viewing window 6 of the electric heating furnace. The laser beam strikes the measurement point on the blade surface through the viewing window 6 and is reflected back to the optical head 2. The relative position is adjusted to ensure the signal strength received by the laser, and the corresponding vibration data is obtained at the signal output terminal. An optical reflective film is attached to the blade surface to reduce laser signal loss. By adjusting the tripod height, vibration response measurements at different blade heights are achieved. The emitted laser spot diameter is within the micrometer range, ensuring high-precision measurement of the response signal.

[0036] like Figure 7 The diagram shows the method for testing the vibration characteristics of a gas turbine damping blade under multiple load conditions, as described in this invention. The specific steps are as follows: Step S1: Place the blade in the heating coil and use the tenon fixing device to constrain the tenon part of the blade in various directions, so that the natural frequency of the blade measured by the force hammer excitation method matches the numerical calculation result, and achieve complete constraint of the tenon. Step S2 involves obtaining the normal pressure load between the contact surfaces of the blade shroud at different rotational speeds through three-dimensional contact finite element analysis based on the blade. The normal pressure on the shroud is then applied by rotating the loading disk, changing the measured tension values ​​on both sides, and adjusting the loading top block. Step S3: Adjust the direction of the high stiffness ratio excitation link to be perpendicular to the surface of the blade excitation point, then install the modal exciter onto the excitation bracket, and use high temperature resistant sealant to fix the flexible link and the blade. Step S4: Install the sealing flange and insert the thermocouple sensor. Completely fill the furnace body opening with thermal insulation material. Set the heating temperature value through the control cabinet. The heating coil works to generate an induced current to heat the blades. The thermocouple measures the temperature of the constant temperature zone inside the furnace in real time. At this time, the indicator light on the temperature control cabinet panel will be green. Step S5: When the measured value reaches the set temperature, the temperature control cabinet switch is automatically turned off, the coil stops heating and maintains fluctuations around the temperature until it finally reaches a stable value. At this time, the indicator light is red. Step S6: By adjusting the input signal, a simple harmonic excitation force with a given amplitude frequency is applied to the blade; Step S7: Adjust the tripod to align the laser sensor with the viewing window, and measure the vibration response signal at different blade heights to obtain the vibration response of the blade at the excitation frequency. Step S8: Adjust the signal generator, change the excitation frequency to perform frequency sweep measurement, repeat step S6, and at the same time monitor the temperature field inside the furnace to keep it stable, and adjust the output power of the power amplifier to ensure that the excitation generated in the test remains constant, and obtain the test data of the blade response curve under high temperature load. Step S9: Adjust the power amplifier to change the amplitude of the excitation force, repeat steps S6 to S8, and measure the vibration response curves of the blade under different excitation forces. Step S10: Adjust the positive pressure loading disk and repeat steps S6 to S8 to obtain the blade vibration frequency response curves under different positive pressure loads. Step S11: Adjust the set temperature value of the temperature control cabinet, and repeat steps S6 to S8 to obtain the blade vibration frequency response curves under different high-temperature heat loads.

[0037] Figure 8A flowchart of the experimental measurement signal processing is provided. The raw signals acquired during the experiment require post-processing to obtain the necessary test data. The laser vibrometer obtains the time-domain signal of the blade's velocity at the measuring point by measuring the Doppler frequency shift of the reflected light wave from the blade surface; this signal needs to be further integrated to obtain the time-domain signal of the displacement. The dynamic force sensor at the loading ring measures the charge signal, which needs to be converted into the corresponding mechanical signal. For the obtained physical quantity signals, the average value needs to be subtracted to remove the DC offset. To eliminate high-frequency noise interference during the measurement process, filtering is typically performed, followed by FFT to obtain the frequency domain signal at the excitation frequency. Finally, the average value of multiple measurement results is taken to avoid the influence of random factors such as improper operation during the test on the analysis results.

[0038] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0039] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0040] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0041] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0042] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

[0043] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this patent should not be determined by reference to the above description, but rather by reference to the foregoing claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the applicant has not considered that subject matter as part of the disclosed inventive subject matter.

Claims

1. A device for testing the vibration characteristics of a gas turbine damping blade under multiple load conditions, characterized in that, It includes an electric heating furnace (4), a damping blade test piece (7), a tenon fixing base (9), a normal pressure loading plate (3), an excitation bracket (32), a high stiffness ratio excitation rod (13), and an optical head (2); The electric heating furnace (4) is equipped with an induction heating coil (5) inside, and the damping blade test piece (7) is placed inside the induction heating coil (5); A tenon clamp (8) is installed on the tenon fixing base (9), and the tenon part of the damping blade test piece (7) is installed in the tenon clamp (8); A loading top block (12) is installed on the positive pressure loading disk (3), and the loading top block (12) is in contact with the damping structure of the damping blade test piece (7); A modal exciter (16) is installed on the excitation bracket (32). One end of the high stiffness ratio excitation rod (13) is connected to the modal exciter (16), and the other end is connected to the blade surface of the damped blade test piece (7). The optical head (2) is connected to the laser controller (1), and the optical head (2) is facing the furnace wall of the electric heating furnace (4).

2. The testing device for vibration characteristics of gas turbine damping blades under multi-load conditions according to claim 1, characterized in that, The top of the electric heating furnace (4) is sealed by a sealing flange (22); a viewing window (6) is provided on the furnace wall of the electric heating furnace (4).

3. The testing device for vibration characteristics of gas turbine damping blades under multi-load conditions according to claim 2, characterized in that, The furnace wall of the electric heating furnace (4) is also provided with a positive pressure loading slot (21), an excitation force loading slot (24) and a tenon tooth fixing slot (25); the loading top block (12) passes through the positive pressure loading slot (21) and contacts the damping structure of the damping blade test piece (7); the high stiffness ratio excitation rod (13) passes through the excitation force loading slot (24) and connects to the damping blade test piece (7); the tenon tooth clamp (8) passes through the tenon tooth fixing slot (25) and is installed on the tenon tooth fixing base (9).

4. The testing device for vibration characteristics of gas turbine damping blades under multi-load conditions according to claim 1, characterized in that, It also includes a loading plate bracket (26), and a positive pressure loading plate (3) is installed on the loading plate bracket (26); a loading pull ring (29) is provided on the positive pressure loading plate (3), and the loading pull ring (29) is connected by a steel wire rope (30), and a dynamic force sensor (15) is connected in series on the steel wire rope (30).

5. The testing device for vibration characteristics of gas turbine damping blades under multi-load conditions according to claim 1, characterized in that, The excitation support (32) is provided with a rotating guide groove (31) for the exciter centered on the axis of the damped blade test piece (7). The position of the modal exciter (16) along the rotating guide groove (31) is adjustable. A dynamic force sensor (15) is provided on the high stiffness ratio excitation rod (13). The dynamic force sensor (15) is located between the modal exciter (16) and the damped blade test piece (7).

6. The testing device for vibration characteristics of gas turbine damping blades under multi-load conditions according to claim 1, characterized in that, A hydraulic jack (14) is provided on the tenon fixing base (9), and the output end of the hydraulic jack (14) abuts against the tenon clamp (8).

7. The testing device for vibration characteristics of gas turbine damping blades under multi-load conditions according to claim 1, characterized in that, The high stiffness ratio excitation rod (13) is a variable cross-section structure, in which the cross-sectional dimensions of the middle section are smaller than those of the two ends.

8. The testing device for vibration characteristics of gas turbine damping blades under multi-load conditions according to claim 1, characterized in that, It also includes a temperature control cabinet (20) and a thermocouple (11). The temperature control cabinet (20) is connected to the induction heating coil (5). The temperature measuring end of the thermocouple (11) extends into the electric heating furnace (4) and is connected to the temperature control cabinet (20).

9. A method for testing the vibration characteristics of a gas turbine damping blade under multi-load conditions based on the device described in any one of claims 1-8, characterized in that, Includes the following steps: Install the tenon part of the damping blade test piece (7) in the tenon clamp (8) and fix the tenon clamp (8) on the tenon fixing base (9); A positive pressure load is applied to the damping structure of the damping blade test piece (7) by means of the loading top block (12) on the positive pressure loading disk (3); One end of the high stiffness ratio excitation rod (13) is fixed to the blade surface of the damped blade test piece (7); The damping blade test piece (7) is placed in the induction heating coil (5) of the electric heating furnace (4), and the induction heating coil (5) is started to heat the damping blade test piece (7) to the preset temperature; A simple harmonic excitation force is applied to the damped blade test piece (7) via a modal exciter (16) and a high stiffness ratio excitation rod (13); The vibration response signal of the damped blade test piece (7) is acquired by an optical head (2) and a laser controller (1).

10. The method for testing the vibration characteristics of a gas turbine damping blade under multiple load conditions according to claim 9, characterized in that, It also includes the following steps: By changing the excitation frequency of the simple harmonic excitation force, frequency sweep measurement was performed to obtain vibration response signals at different excitation frequencies. By changing the amplitude of the simple harmonic excitation force and repeatedly performing frequency sweep measurements, vibration response signals under different excitation force amplitudes can be obtained. By changing the magnitude of the normal pressure load and repeatedly performing frequency sweep measurements, vibration response signals under different normal pressure loads can be obtained. By changing the preset temperature value and repeatedly performing frequency sweep measurements, vibration response signals at different temperatures can be obtained.

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