A high temperature damping blade vibration simulation test device and an operating method thereof

Abstract

This invention discloses a high-temperature damping blade vibration simulation testing device and its operation method. The high-temperature damping blade vibration simulation testing device includes a test bench base; a support frame disposed on the test bench base; a blade fixing frame for fixing and installing the damping blade to be tested; a shroud normal pressure loading device for fixing and applying normal pressure to the shroud area of ​​the damping blade to be tested; a vibration force loading device for applying vibration force to the damping blade to be tested; a heating device for heating the blade area; and a measurement and control device for controlling and adjusting the normal pressure loading, vibration force loading, and heating temperature to realize high-temperature damping blade vibration simulation testing. This invention can simulate the blade vibration response when a damping blade is subjected to certain normal pressure, vibration force, and thermal load, and can provide important data and theoretical guidance for the study of the vibration characteristics of damping blades in high-temperature turbine machinery.

Description

Technical Field

[0001] This invention belongs to the field of experimental device technology, specifically the field of vibration simulation testing, and particularly relates to a high-temperature damping blade vibration simulation testing device and its operation method. Background Technology

[0002] Steam turbines, gas turbines, and other similar equipment are crucial power units in the power industry, industrial manufacturing, and marine propulsion. Their safety and reliability are paramount to economic security. Operational experience shows that turbine blade damage is a major cause of failure in rotating machinery such as steam turbines and gas turbines, and blade vibration fatigue is the primary cause of blade damage. To improve blade vibration safety, commonly used turbine blades are typically designed with damping structures. These damping structures dissipate vibration energy through dry friction, thereby reducing blade vibration stress.

[0003] As the economic requirements for turbine machinery such as gas turbines, large nuclear power turbines, and ultra-supercritical turbines become increasingly stringent, the operating temperatures of these machines are also rising, leading to a significant increase in the inlet temperature of turbine blades. Against this backdrop, turbine blades frequently operate in high-temperature environments. These high temperatures affect the overall material properties of damping blades, consequently influencing the material characteristics, working mechanism, and vibration reduction effect of the damping structure, thus threatening the fatigue resistance and stability of the blades.

[0004] Current research on the vibration performance of damping blades is mostly conducted in ambient temperature environments, and research on the vibration performance of damping blades in high-temperature environments is still insufficient. Furthermore, no scholars have established a vibration testing platform for damping blades in high-temperature environments. Therefore, it is urgent to establish a vibration simulation testing device for damping blades in high-temperature environments. Summary of the Invention

[0005] The purpose of this invention is to provide a high-temperature damped blade vibration simulation testing device and its operating method to solve one or more of the aforementioned technical problems. The technical solution provided by this invention can simulate the vibration response of a damped blade under certain normal pressure, excitation force, and thermal load, providing important data and theoretical guidance for the study of the vibration characteristics of damped blades in high-temperature turbine machinery.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The present invention provides a high-temperature damping blade vibration simulation test device, comprising:

[0008] The test bench base serves as a support base for the high-temperature damping blade vibration simulation test device.

[0009] A support frame is fixedly mounted on the base of the test bench, and the support frame is provided with a first sliding groove;

[0010] A blade holder is fixedly mounted on the test bench base and is used to fix and install the damping blade to be tested.

[0011] A shroud positive pressure loading device is movably installed in the first slide groove of the support frame and is used to fix and apply positive pressure to the shroud area of ​​the damping blade to be tested.

[0012] A vibration force loading device is movably installed in the first slide groove of the support frame and is used to apply vibration force to the damping blade under test.

[0013] A heating device is fixedly mounted on the test bench base or the blade holder; the heating device is used to enclose the blade area of ​​the damping blade to be tested and to heat the blade area.

[0014] A measurement and control device is provided to control and adjust the positive pressure loading of the shroud positive pressure loading device, the excitation force loading of the excitation force loading device, and the heating temperature of the heating device, so as to realize the high-temperature damping blade vibration simulation test.

[0015] A further improvement of the present invention is that the support frame is provided with the first sliding groove in the following specific structure:

[0016] The support frame is provided with a vertical sliding groove, and the sliding groove is provided with fixing holes at multiple preset height positions. The fixing holes are used to fix the shroud positive pressure loading device or the excitation force loading device.

[0017] A further improvement of the present invention is that the blade holder comprises:

[0018] The mounting bracket is fixedly mounted on the base of the test bench;

[0019] Leaf root clamp fixing block, the leaf root clamp fixing block is fixedly mounted on the mounting bracket;

[0020] Leaf root clamp limiter, the leaf root clamp limiter is fixedly mounted on the leaf root clamp fixing block;

[0021] A leaf root clamp is fixedly mounted on the leaf root clamp limiter.

[0022] A further improvement of the present invention is that a heat insulation plate is provided between the leaf root clamp fixing block and the leaf root clamp limiter.

[0023] A further improvement of the present invention is that the annular positive pressure loading device includes:

[0024] The mounting side plate is movably mounted in the first slide groove of the support frame;

[0025] A positive pressure loading disk is fixedly mounted on the mounting side plate; the positive pressure loading disk is provided with a through hole for passing through the shroud area of ​​the damping blade to be tested;

[0026] An arc-shaped sliding groove is fixedly disposed on the positive pressure loading plate around the through hole;

[0027] A positive pressure application device, wherein there are multiple positive pressure application devices, all of which are slidably disposed in the arc-shaped first groove, for fixing and applying positive pressure to the surrounding area of ​​the damping blade to be tested.

[0028] The positive pressure application device includes a positive pressure application rod; the positive pressure application rod is equipped with a static force sensor for measuring the magnitude of the positive pressure applied; the rear end of the positive pressure application rod is equipped with an adjusting bolt for adjusting the magnitude of the applied positive pressure; and the front end of the positive pressure application rod is equipped with a heat insulation sheet and a heat-resistant top block.

[0029] A further improvement of the present invention is that the excitation force loading device includes:

[0030] A vibrator bracket is provided, which is movably mounted in a first slide groove of the support frame, and the vibrator bracket is provided with a second slide groove.

[0031] The vibrator chassis is movably mounted in the second slide groove of the vibrator bracket, and the vibrator chassis is provided with a third slide groove;

[0032] The vibrator is movably mounted in the third slide groove of the vibrator chassis; a dynamic force sensor is provided on the excitation rod of the vibrator, and the excitation rod is used to apply excitation force to the damping blade under test through the heating device.

[0033] A further improvement of the present invention is that the excitation rod of the exciter is a flexible variable cross-section connecting rod.

[0034] A further improvement of the present invention is that the heating device includes: a resistance heating furnace and a high-temperature gas flow system.

[0035] A further improvement of the present invention is that the measurement and control device includes: a signal generator, a power amplifier, a thermocouple, a data acquisition unit, a data processing workstation, a high-temperature strain gauge, a laser reflective coating, and a laser Doppler vibration meter;

[0036] The signal generated by the signal generator is used to be introduced into the exciter through the power amplifier to adjust the excitation force; the thermocouple is used to be placed on the surface of the heating device to measure the temperature of the test environment; the data acquisition unit is used to acquire the normal pressure measured by the static force sensor and the excitation force measured by the dynamic force sensor.

[0037] The high-temperature strain gauges are multiple and are fixedly installed at different preset positions on the damping blade to be tested; the high-temperature strain gauges are connected to the data acquisition unit; the laser reflective coatings are multiple and are installed at different preset positions on the damping blade to be tested; the laser Doppler vibration meter is used to measure the vibration displacement of the laser reflective coating area;

[0038] The data acquisition device is connected to the data processing workstation.

[0039] The present invention provides an operating method for a high-temperature damping blade vibration simulation testing device, comprising the following steps:

[0040] The damping blade to be tested is fixedly installed on the blade holder and placed in the heating device, so that the natural frequency measured in the free state of the blade is consistent with the frequency obtained by numerical analysis in the fully constrained state of the blade root.

[0041] After the temperature field of the heating device stabilizes, the surrounding area of ​​the damping blade under test is fixed and subjected to positive pressure by the surrounding positive pressure loading device, and the damping blade under test is subjected to excitation force by the excitation force loading device. The vibration response of the blade under a certain contact surface positive pressure load and a certain excitation frequency is measured and obtained. The vibration frequency response curve of the blade under a certain contact surface positive pressure load under high temperature load is obtained. The vibration frequency response curve of the blade under multiple different contact surface positive pressure loads under high temperature load is obtained.

[0042] The modal damping ratio of the blade is calculated based on the frequency response curves under various operating conditions, and the damping characteristics of the blade damping shroud under different normal pressure loads are analyzed.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] Addressing the current technical deficiencies in high-temperature testing conditions and research on damping blades, this invention specifically discloses a high-temperature damping blade vibration simulation testing device. The entire testing device is mounted on a test bench base, and the damping blade to be tested is fixed by a blade fixing frame. A sliding groove is arranged on the support frame, and a surrounding normal pressure loading device and an excitation force loading device are arranged on the sliding groove, which can apply excitation force and normal pressure to the blade respectively. A heating device is arranged around the blade to heat the blade area. The device provided by this invention can simulate the vibration response of a damping blade under certain normal pressure, excitation force, and thermal load, and then process the data to obtain the frequency response curve of the blade, providing important data for the vibration characteristics of damping blades in high-temperature turbine machinery such as gas turbines.

[0045] In this invention, a combination of contact and non-contact measurement methods is used to accurately measure the vibration response of blades. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art are briefly introduced below; obviously, the drawings described below are some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0047] Figure 1 This is a schematic diagram of the structure of a high-temperature damping blade vibration simulation test device provided in an embodiment of the present invention;

[0048] Figure 2 This is a schematic diagram of the structure of the base frame in an embodiment of the present invention;

[0049] Figure 3 This is a schematic diagram of the leaf root fixing device in an embodiment of the present invention; wherein, Figure 3 (a) is a schematic diagram of the whole. Figure 3 (b) is an enlarged schematic diagram of the leaf root clamp fitting part;

[0050] Figure 4 This is a schematic diagram of the positive pressure loading device for the shroud in an embodiment of the present invention; wherein, Figure 4 (a) is a schematic diagram of the whole. Figure 4 Image (b) is a magnified view of a portion of the positive pressure loading disk. Figure 4 (c) is a magnified view of the loaded top block;

[0051] Figure 5 This is a schematic diagram of the excitation force loading device in an embodiment of the present invention; wherein, Figure 5 (a) is a schematic diagram of the whole. Figure 5 (b) is Figure 5Partial sectional view at point AA in (a)

[0052] Figure 6 This is a schematic diagram of a resistance heating furnace device in an embodiment of the present invention; wherein, Figure 6 (a) is a frontal view. Figure 6 (b) is a side view diagram. Figure 6 (c) is Figure 6 (b) Schematic cross-sectional view at point AA;

[0053] Figure 7 This is a schematic diagram of a high-temperature gas flow device in an embodiment of the present invention;

[0054] Figure 8 This is a schematic diagram of blade strain measurement in an embodiment of the present invention;

[0055] Figure 9 This is a schematic diagram of the measurement and control device in an embodiment of the present invention;

[0056] Figure 10 This is a schematic diagram of the operation method of a high-temperature damping blade vibration simulation test device provided in an embodiment of the present invention;

[0057] In the diagram, 1. Test bench base; 2. Support frame; 3. Top support rod; 5. Blade fixing frame;

[0058] 7. Heat insulation board; 10. Blade root clamp fixing block; 11. Blade root clamp limiter; 12. Blade root clamp; 13. Blade root structure; 14. Blade body;

[0059] 15. L-shaped side plate; 16. Positive pressure loading plate; 17. Arc-shaped slide groove; 18. Adjusting bolt; 19. Convex slider; 20. Static force sensor; 21. Positive pressure application rod; 22. Heat insulation sheet; 23. Heat-resistant top block;

[0060] 24. Vibrator bracket; 25. Vibrator chassis; 26. Vibrator; 27. Variable cross-section vibration rod; 28. Dynamic force sensor; 29. ​​Thermal insulation material;

[0061] 30. Resistance heating furnace; 31. Observation window; 32. Flange sealing cover; 33. High-temperature gas flow flange; 34. Pipe heater; 35. Pipe heater base; 36. Heating tube; 37. Blower; 38. High-temperature gas flow pipe;

[0062] 39. Data processing workstation; 40. Data acquisition unit; 41. Signal generator; 42. Power amplifier; 43. Thermocouple; 44. High-temperature strain gauge; 45. Laser reflective coating; 46. Laser Doppler vibration meter. Detailed Implementation

[0063] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0064] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0065] The present invention will now be described in further detail with reference to the accompanying drawings:

[0066] Please see Figure 1 The present invention provides a high-temperature damping blade vibration simulation test device, comprising: a base frame, a blade root fixing device, a shroud positive pressure loading device, an excitation force loading device, a heating device, and a measurement and control device.

[0067] In this embodiment of the invention, two support frames 2 and one blade fixing frame 5 are arranged on the test bench base 1 of the basic test bench. Vertical grooves are arranged on the sides of the support frames 2, allowing the shroud positive pressure loading device and the excitation force loading device to move and be fixed freely on the grooves. This allows for position adjustment for damping blades of different shapes and heights, achieving positive pressure loading on the blade tip shroud and excitation force loading on the blade body 14. In the technical solution provided by this embodiment, the support frames 2 also have vertical fixing groove structures, enabling vertical height adjustment of the shroud positive pressure loading device and the excitation force loading device, thereby adapting to different blade geometries. Please refer to [link to relevant documentation]. Figure 2Specifically, exemplarily, the foundation frame of this invention comprises a test bench base 1, a support frame 2, a top support rod 3, and a blade fixing frame 5. The bottom of the support frame 2 is fixed to the test bench base 1, and the side of the support frame 2 has a vertically oriented sliding groove structure for fixing and adjusting the positions of the circumferential positive pressure loading device and the excitation force loading device. The top support rod 3 fixes the left and right support frames 2 with bolts, thus stabilizing the foundation frame. The bottom of the blade fixing frame 5 is fixed to the test bench base 1 and is used to fix the blade root fixing device.

[0068] In this embodiment of the invention, the blade holder 5 has a groove for fixing the blade root fixing device. The blade root fixing device is mounted on the blade holder 5 via the blade root clamp fixing block 10, and the heat insulation plate 7, the blade root clamp limiter 11, and the blade root clamp 12 are sequentially mounted on it. The heat insulation plate 7 can block most of the heat load from the high-temperature test environment, protecting the non-high-temperature areas. The combined use of the blade root clamp limiter 11 and the blade root clamp 12 allows for replacement of the blade test specimen by simply replacing the blade root profile in the blade root clamp 12, greatly reducing the cost and time of the test. Please refer to [link / reference]. Figure 3 Specifically, exemplarily, the blade root fixing device of this invention comprises a heat insulation plate 7, a blade root clamp fixing block 10, a blade root clamp limiter 11, and a blade root clamp 12; wherein, the blade root clamp fixing block 10 is installed and fixed on the blade fixing frame 5, and the blade root clamp fixing block 10, the heat insulation plate 7, the blade root clamp limiter 11, and the blade root clamp 12 are fixed in sequence; see also Figure 3 In section (b), in the mating part of the blade root clamp 12, the blade root clamp limiter 11 is fixed with the heat insulation plate 7 and the blade root clamp fixing block 10, which can realize the installation limit and fixation of the blade root clamp 12; after the blade root clamp 12 is installed in place, it is fixed with the blade root clamp limiter 11; different shapes of blade root clamps 12 can realize the mating with different blade root structures 13, thereby realizing the fixation of the entire blade. In the technical solution provided by the embodiment of the present invention, the assembly and fixation of the blade root clamp limiter 11 and the blade root clamp 12 adopts a sliding groove method; this fixing method makes the assembly of the blade root clamp 12 simple and convenient, and the blade root clamp 12 designed for different blades only needs to change the blade root profile, without redesigning the entire blade root clamp 12.

[0069] In this embodiment of the invention, the shroud positive pressure loading device is equipped with a positive pressure loading disk 16, and four positive pressure application devices slide in the arc-shaped grooves 17 on it, which can realize the fixing and positive pressure loading of damping blade shrouds of different shapes; each of the four positive pressure application devices is equipped with a static force sensor 20, which can measure the magnitude of the positive pressure loading in four directions in real time; an adjusting bolt 18 is provided at the rear of the positive pressure application device, which can adjust the magnitude of the positive pressure applied; a heat insulation plate 22 and a heat-resistant top block 23 are installed at the front end of the positive pressure application device, and the heat-resistant top block 23 contacts the blade shroud, which can block most of the high temperature from the blade. Please refer to Figure 4 Specifically, exemplarily, the positive pressure loading device for the shroud comprises an L-shaped side plate 15, a positive pressure loading disc 16, an arc-shaped slide groove 17, an adjusting bolt 18, a convex slider 19, a static force sensor 20, a positive pressure applying rod 21, a heat insulation sheet 22, and a heat-resistant top block 23; wherein, Figure 4 Image (a) shows an overall view of the shroud positive pressure loading device. Figure 4 Image (b) shows a partially enlarged view of the positive pressure loading device for the shroud. The L-shaped side plates 15 are bolted to the support frame 2, and the positive pressure loading disc 16 is fixed between the two L-shaped side plates 15. By adjusting the position of the L-shaped side plates 15 on the support frame 2, the vertical direction of the positive pressure loading disc 16 can be adjusted, thereby achieving the fixation of shrouds for blades of different shapes. Two arc-shaped grooves 17 are arranged in the middle of the positive pressure loading disc 16, and a total of four sets of positive pressure applying rods 21 are arranged on the two arc-shaped grooves 17. See also... Figure 4 In section (b), four convex sliders 19 are arranged on two arc-shaped grooves 17. The convex sliders 19 can slide freely within the arc-shaped grooves 17 to apply normal pressure to the blade damping shroud at different orientations. An adjusting bolt 18 is installed inside the convex slider 19, and the magnitude of the applied normal pressure can be changed by adjusting the adjusting bolt 18. A static force sensor 20 is installed at the end of the connecting rod of the adjusting bolt 18, enabling real-time measurement of the magnitude of the applied normal pressure. The normal pressure application rod 21 is connected to the static force sensor 20 and extends into the resistance heating furnace 30. The space between the positive pressure applying rod 21 and the surface hole of the resistance heating furnace 30 is filled with heat insulation material 29; the front end of the positive pressure applying rod 21 is fixed with a heat insulation plate 22 and a heat-resistant top block 23. The heat-resistant top block 23 is made of high temperature resistant material and is in direct contact with the blade damping belt to realize the fixation of the damping belt and the application of positive pressure; the heat insulation plate 22 is arranged between the heat-resistant top block 23 and the positive pressure applying rod 21, which can block most of the heat conduction from the high temperature test blade.

[0070] In this embodiment of the invention, the excitation force loading device is equipped with an exciter bracket 24 and an exciter chassis 25. The exciter 26 is fixed on the exciter chassis 25 and can slide on the exciter chassis 25. The exciter chassis 25 can in turn slide on the exciter bracket 24, thus achieving excitation force loading at different positions on the blade. The exciter 26 adopts a variable cross-section excitation rod 27, on which a dynamic force sensor 28 is arranged to measure the magnitude of the excitation force in real time. In the technical solution provided by this embodiment of the invention, the exciter 26 adopts a flexible variable cross-section connecting rod, which can avoid the influence of nonlinear excitation on the blade caused by additional constraints. In addition, a sand and gravel filling area can be arranged around the entire test bench base 1 to achieve vibration isolation from the outside. Please refer to [link to relevant documentation]. Figure 5 Specifically, exemplarily, the excitation force loading device of this invention comprises an exciter bracket 24, an exciter chassis 25, an exciter 26, a variable cross-section excitation rod 27, a dynamic force sensor 28, and heat insulation material 29. The exciter bracket 24 is fixed to a support frame 2 and has a sliding groove. The exciter chassis 25 is fixed to the sliding groove and can slide on the exciter bracket 24. The surface of the exciter chassis 25 has a sliding groove, and the exciter 26 is fixed to the sliding groove and can slide within it. The variable cross-section excitation rod 27 is connected to the exciter 26, and the dynamic force sensor 28 is arranged in the middle of the variable cross-section excitation rod 27 and outside the resistance heating furnace 30. The variable cross-section excitation rod 27 extends into the resistance heating furnace 30 through a hole and applies the excitation force to the blade body 14. The space between the variable cross-section excitation rod 27 and the hole in the resistance heating furnace 30 is filled with heat insulation material 29.

[0071] In this embodiment of the invention, the heating device consists of a resistance heating furnace 30 and a high-temperature gas flow section. The resistance heating furnace 30 is directly fixed to the base frame, and its top is sealed with a flange sealing cover 32. The entire heating furnace device precisely encloses the complete blade area, realizing the functions of heating and temperature control of the blade area. Please refer to [link / reference]. Figure 6 Specifically, exemplarily, the resistance heating furnace 30 device comprises a resistance heating furnace body, an observation window 31, a flange sealing cover 32, and a high-temperature gas flow flange 33. The resistance heating furnace body is fixed on a support frame 2, on which the observation window 31 is arranged. The observation window 31 enables real-time observation of the working environment inside the resistance heating furnace body. After removing the observation window 31, the position and installation of the high-temperature strain gauge 44 can be adjusted. The flange sealing cover 32 is fixed to the top of the resistance heating furnace 30 by threads, achieving a top seal of the resistance heating furnace body. The high-temperature gas flow flange 33 is arranged at the bottom of the resistance heating furnace body. High-temperature air flowing in from the high-temperature gas flow device will flow into the resistance heating furnace body through the high-temperature gas flow flange 33, thereby accelerating the rise and stabilization of the temperature inside the resistance heating furnace 30.

[0072] In this embodiment of the invention, the high-temperature gas flow section is arranged outside the test bench base 1 and consists of a blower 37, a pipe heater 34, and a high-temperature gas flow pipe 38. The blower 37 blows air into the pipe heater 34 to obtain heated high-temperature gas. This high-temperature gas is then input into the furnace chamber of the resistance heating furnace 30 through the flow pipe, thereby heating the internal space of the resistance heating furnace 30. Please refer to [link / reference]. Figure 7 Specifically, the high-temperature gas flow device of this invention comprises a pipe heater 34, a pipe heater base 35, a heating pipe 36, a blower 37, and a high-temperature gas flow pipe 38. The pipe heater 34 and the blower 37 are arranged outside the test bench base 1. The base of the pipe heater 34 is equipped with pulleys, allowing it to move around the test bench. During the test, the blower 37 can blow pressurized air into the pipe heater 34. The air is heated to high temperature as it flows through the heating pipe 36, and the temperature of the heating pipe 36 can be adjusted by adjusting the control panel of the pipe heater 34. After being heated by the pipe heater 34, the high-temperature air flows along the high-temperature gas flow pipe 38 into the high-temperature gas flow flange 33 and the resistance heating furnace 30. The high-temperature gas flow pipe 38 is externally wrapped with heat-insulating cotton.

[0073] In this embodiment of the invention, the measurement and control device can measure and control the normal pressure of the shroud using a static force sensor 20 and adjusting bolt 18; by applying preset signals from a dynamic force sensor 28, signal generator 41, and power amplifier 42, the excitation force can be measured and controlled; the temperature of the resistance heating furnace 30 can be monitored in real time using a thermocouple 43 on the outer wall of the resistance heating furnace 30; and the temperature of the resistance heating furnace 30 and the pipe heater 34 can be adjusted by sensing the temperature of the thermocouple 43, thus achieving temperature control of the test environment. By using a combination of contact and non-contact measurement methods, including a high-temperature strain gauge 44 and a laser Doppler vibration meter 46, accurate measurement of the blade vibration response can be achieved.

[0074] Please see Figure 8 and Figure 9 The measurement and control device of this invention includes: a data processing workstation 39, a data acquisition unit 40, a high-temperature strain gauge 44, a laser reflective coating 45, and a laser Doppler vibration meter 46; this invention adopts a measurement method that combines contact measurement and non-contact measurement.

[0075] In this embodiment of the invention, the measurement and control device comprises a data processing workstation 39, a data acquisition unit 40, a signal generator 41, a power amplifier 42, and a thermocouple 43. The signal generated by the signal generator 41 is input into the exciter 26 via the power amplifier 42, enabling adjustment of the excitation force. Thermocouple 43 is positioned on the surface of the resistance heating furnace 30 to measure the ambient temperature. The static force sensor 20 measures the positive pressure applied by the surrounding positive pressure loading device, while the dynamic force sensor 28 measures the excitation force. All measurement signals are input into the data acquisition unit 40 and displayed in real time on the data processing workstation 39. Based on the parameters displayed on the data processing workstation 39, the measurement and control device further adjusts each parameter.

[0076] In this embodiment of the invention, the contact measurement method includes: uniformly arranging high-temperature strain gauges 44 on the upper, middle, and lower parts of the blade, and connecting the high-temperature strain gauges 44 to a data acquisition unit 40 and a data processing workstation 39; the non-contact measurement method includes: arranging observation windows 31 of a resistance heating furnace 30 at approximately 30%, 60%, and 90% of the blade height, and spraying a laser reflective coating 45 onto the corresponding blade surface areas; installing a laser Doppler vibration meter 46 around the test bench, and allowing it to measure the vibration displacement of the laser reflective coating 45 area on the blade body 14 through the observation windows 31. Combining contact and non-contact measurements allows for the integration of local point measurements and regional measurements, achieving comprehensive and accurate measurement of the strain of the high-temperature damped blade.

[0077] In the technical solution provided by this embodiment of the invention, an observation window 31 is arranged on the surface of the resistance heating furnace 30. The observation window 31 is made of heat-insulating glass, allowing for observation of the working status of the high-temperature strain gauges 44 inside the resistance heating furnace 30 at any time. The laser Doppler vibration meter 46 can also perform non-contact vibration measurement through the observation window 31. Simultaneously, the arrangement of the high-temperature strain gauges 44 inside can be adjusted by removing the observation window 31. The geometric shape of the observation window 31 is not limited to a circle; it can also be rectangular, irregular quadrilateral, or other polygonal shapes. Furthermore, the arrangement of the observation window 31 is not limited to a single location; its position can be adjusted according to the area required for the vibration test of the damping blades, and the number of observation windows can be increased. In the technical solution provided by this embodiment of the invention, the gaps between the resistance heating furnace 30 and the outside are filled with heat-insulating materials 29 such as asbestos; this ensures the temperature stability of the test environment while isolating the external test equipment from high temperatures to a certain extent.

[0078] Please see Figure 10 To further understand the high-temperature damping blade vibration simulation testing device of the present invention, its operation steps are further explained as follows:

[0079] (1) The blade root structure 13 is constrained by the blade root clamp 12 in the radial, tangential and axial directions, so that the natural frequency measured in the free state of the blade is consistent with the frequency obtained by numerical analysis in the fully constrained state of the blade root, thereby ensuring that the blade root is fully constrained.

[0080] (2) Install and fix the resistance heating furnace 30 and the pipe heater 34, set the heating equipment according to the temperature required by the test, and connect the thermocouple 43 sensor to monitor the temperature inside the furnace in real time; adjust the heating temperature rise rate through the control cabinet to achieve uniform loading of current intensity, and finally form a stable temperature field; the opening of the furnace body is completely filled with heat insulation material 29.

[0081] (3) Install the shroud positive pressure loading device. Based on the three-dimensional contact finite element numerical analysis results of the blade, determine the positive pressure load between the blade shroud contact surfaces under a given speed condition. After the temperature field stabilizes, apply the corresponding positive pressure to the blade damping shroud using the positive pressure loading disk 16.

[0082] (4) Install the excitation force loading device, adjust the direction of the variable cross-section excitation rod 27 to be perpendicular to the surface of the blade body 14, and connect and fix the variable cross-section excitation rod 27 to the blade body 14 with nuts. After the temperature field stabilizes, adjust the signal generator 41 and the power amplifier 42 to apply a simple harmonic excitation force with a certain amplitude and a certain excitation frequency to the blade body 14;

[0083] (5) The vibration response of the blade is measured by high-temperature strain gauges 44 arranged along the blade height or by an eddy current displacement sensor brought out of the heating furnace, and the vibration response of the blade under a certain contact surface normal pressure load and a certain excitation frequency is obtained.

[0084] (6) Change the excitation frequency and repeat the operation after step (3) to perform the measurement. During this process, it is necessary to monitor the stability of the temperature field inside the furnace. By continuously adjusting the output power of the power amplifier 42, the amplitude of the excitation force is kept constant during the test, and the vibration frequency response curve of the blade under a certain contact surface normal pressure load under high temperature load is obtained.

[0085] (7) Replace the contact surface normal pressure load corresponding to the next rotation speed, repeat the operation after step (2) to measure, and finally obtain the vibration frequency response curve of the blade under high temperature load under multiple different contact surface normal pressure loads.

[0086] (8) Calculate the modal damping ratio of the blade based on the frequency response curves under each working condition, and analyze the damping characteristics of the blade damping shroud under different normal pressure loads.

[0087] The technical solution provided by the embodiments of the present invention can apply positive pressure loads to blades of different shapes; the positive pressure loading disk can apply different magnitudes of positive pressure to the blade tip shroud of different shapes through real-time data display of static force sensors, adjustment of adjusting bolts, and sliding of convex sliders in arc-shaped grooves, and is easy to adjust.

[0088] The technical solution provided by the embodiments of the present invention can achieve temperature control and stability of the test area; the resistance heating furnace, the high-temperature gas flow device and the thermocouple arranged on the resistance heating furnace can achieve temperature control of the test environment, so that the test environment temperature is constant; and the dual heating system of the resistance heating furnace and the high-temperature gas flow device can further improve the speed of temperature control and effectively prevent the failure of a single system.

[0089] The technical solution provided by this invention can apply excitation forces to blades under various working conditions. Both the exciter chassis and the exciter support are equipped with sliding groove structures, and the exciter support can be adjusted vertically within the support frame, allowing the exciter to move in four degrees of freedom: three translational directions and a horizontal rotational direction. This allows the excitation force application position to be adjusted according to the blade shape and the position of the resistance heating furnace. Furthermore, by adjusting the signal generator and power amplifier, excitation forces of different frequencies and amplitudes can be applied to the blades.

[0090] The technical solution provided by this invention can achieve relatively accurate vibration measurement of high-temperature damped blades. It employs a vibration displacement measurement method combining contact and non-contact measurement. High-temperature strain gauges, directly attached to the blade surface, allow for small-scale strain measurement at key monitoring locations with relatively concentrated stress. Meanwhile, a non-contact laser Doppler vibration meter measures the vibration displacement within a certain range through an observation window on a resistance heating furnace. This combination of local point measurement and regional measurement can largely ensure the accurate measurement of blade vibration displacement.

[0091] The technical solution provided by the embodiments of the present invention can ensure that the test device can work normally under high temperature test. The present invention has heat insulation sheets and heat insulation plates arranged in the surrounding positive pressure loading device and the blade root fixing device; the parts of the resistance heating furnace that come into contact with the outside are filled with heat insulation material, which can largely prevent high temperature from damaging the external equipment while ensuring the high temperature test, so that the test device can work normally.

[0092] The testing device provided in this embodiment of the invention can not only perform tests in high-temperature environments, but also in normal-temperature environments; furthermore, the test objects of this device are not limited to turbine blades, but can also be used to test blades of other rotating machinery.

[0093] In summary, the technical solution provided by the embodiments of the present invention can realize the vibration simulation test of damped blades under high-temperature environments, and obtain the influence of multiple factors such as normal pressure, excitation force, and temperature on the vibration characteristics of damped blades. Simultaneously, the embodiments of the present invention construct a complete measurement and control device, which can realize real-time monitoring and adjustment of temperature data, excitation force data, and normal pressure data; achieve real-time and accurate measurement of blade vibration displacement; and the test process has a high degree of automation and is easy to operate. The present invention can provide a test platform and data support for the vibration performance testing of damped blades in high-temperature environments such as gas turbines.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A high-temperature damped blade vibration simulation test device, characterized in that, include: Test bench base (1), the test bench base (1) is used as the support base of the high temperature damping blade vibration simulation test device. Support frame (2), the support frame (2) is fixedly installed on the test bench base (1), and the support frame (2) is provided with a first sliding groove; Blade fixing frame (5), the blade fixing frame (5) is fixedly installed on the test bench base (1), the blade fixing frame (5) is used to fix and install the damping blade to be tested; A positive pressure loading device for the shroud is movably installed in the first groove of the support frame (2) for fixing and applying positive pressure to the shroud area of ​​the damping blade to be tested. Excitation force loading device, which is movably installed in the first groove of the support frame (2) for applying excitation force to the damping blade under test; A heating device is fixedly mounted on the test bench base (1) or the blade fixing frame (5); the heating device is used to enclose the blade area of ​​the damping blade to be tested and heat the blade area. A measurement and control device is used to control and adjust the positive pressure loading of the shroud positive pressure loading device, the excitation force loading of the excitation force loading device, and the heating temperature of the heating device to realize high-temperature damped blade vibration simulation test. The surrounding belt positive pressure loading device includes: The mounting side plate is movably mounted in the first groove of the support frame (2); A positive pressure loading disk (16) is fixedly mounted on the mounting side plate; the positive pressure loading disk (16) is provided with a through hole, which is used to pass through the surrounding area of ​​the damping blade to be tested; Arc-shaped slide groove (17), the arc-shaped slide groove (17) is fixedly disposed on the positive pressure loading disk (16) around the through hole; A positive pressure application device, wherein there are multiple positive pressure application devices, all of which are slidably disposed in the arc-shaped groove (17) for fixing and applying positive pressure to the surrounding area of ​​the damping blade to be tested. The positive pressure application device includes a positive pressure application rod (21); the positive pressure application rod (21) is equipped with a static force sensor (20) for measuring the magnitude of the positive pressure loading; the rear end of the positive pressure application rod (21) is equipped with an adjustment bolt (18) for adjusting the magnitude of the positive pressure application; the front end of the positive pressure application rod (21) is equipped with a heat insulation sheet (22) and a heat-resistant top block (23).

2. The high-temperature damped blade vibration simulation test device according to claim 1, characterized in that, The specific structure of the support frame (2) with the first sliding groove is as follows: The support frame (2) is provided with a vertical sliding groove, and the sliding groove is provided with fixing holes at multiple preset different height positions. The fixing holes are used to fix the positive pressure loading device of the shroud or the excitation force loading device.

3. The high-temperature damped blade vibration simulation test device according to claim 1, characterized in that, The blade holder (5) includes: The mounting bracket is fixedly mounted on the test bench base (1); Leaf root clamp fixing block (10), the leaf root clamp fixing block (10) is fixedly installed on the mounting bracket; Leaf root clamp limiter (11), the leaf root clamp limiter (11) is fixedly mounted on the leaf root clamp fixing block (10); Leaf root clamp (12), the leaf root clamp (12) is fixedly mounted on the leaf root clamp limiter (11).

4. The high-temperature damped blade vibration simulation test device according to claim 3, characterized in that, A heat insulation plate (7) is also provided between the leaf root clamp fixing block (10) and the leaf root clamp limiter (11).

5. The high-temperature damped blade vibration simulation test device according to claim 1, characterized in that, The excitation force loading device includes: Vibrator bracket (24), the vibrator bracket (24) is movably installed in the first slide groove of the support frame (2), the vibrator bracket (24) is provided with a second slide groove; The exciter chassis (25) is movably installed in the second slide groove of the exciter bracket (24), and the exciter chassis (25) is provided with a third slide groove; The exciter (26) is movably installed in the third slide groove of the exciter chassis (25); a dynamic force sensor (28) is provided on the excitation rod of the exciter (26), and the excitation rod is used to pass into the heating device to apply excitation force to the damping blade under test.

6. The high-temperature damped blade vibration simulation test device according to claim 5, characterized in that, The excitation rod of the exciter is a flexible variable cross-section connecting rod.

7. The high-temperature damped blade vibration simulation test device according to claim 1, characterized in that, The heating device includes: a resistance heating furnace (30) and a high-temperature gas flow system.

8. The high-temperature damped blade vibration simulation test device according to claim 5, characterized in that, The measurement and control device includes: a signal generator (41), a power amplifier (42), a thermocouple (43), a data acquisition unit (40), a data processing workstation (39), a high-temperature strain gauge (44), a laser reflective coating (45), and a laser Doppler vibration meter (46). The signal generated by the signal generator (41) is used to be introduced into the exciter (26) through the power amplifier (42) to adjust the excitation force; the thermocouple (43) is used to be placed on the surface of the heating device to measure the temperature of the test environment; the data acquisition unit (40) is used to acquire the positive pressure measured by the static force sensor (20) and the excitation force measured by the dynamic force sensor (28); The high-temperature strain gauges (44) are in multiple quantities and are respectively used to fix them at different preset positions on the damping blade to be tested; the high-temperature strain gauges (44) are connected to the data acquisition unit (40); the laser reflective coating (45) is in multiple quantities and is respectively used to set at different preset positions on the damping blade to be tested; the laser Doppler vibration meter (46) is used to measure the vibration displacement of the laser reflective coating (45) area; The data acquisition unit (40) is connected to the data processing workstation (39).

9. A method for operating the high-temperature damped blade vibration simulation test device according to claim 1, characterized in that, Includes the following steps: The damping blade to be tested is fixedly installed on the blade holder and placed in the heating device, so that the natural frequency measured in the free state of the blade is consistent with the frequency obtained by numerical analysis in the fully constrained state of the blade root. After the temperature field of the heating device stabilizes, the surrounding area of ​​the damping blade under test is fixed and subjected to positive pressure by the surrounding positive pressure loading device, and the damping blade under test is subjected to excitation force by the excitation force loading device. The vibration response of the blade under a certain contact surface positive pressure load and a certain excitation frequency is measured and obtained. The vibration frequency response curve of the blade under a certain contact surface positive pressure load under high temperature load is obtained. The vibration frequency response curve of the blade under multiple different contact surface positive pressure loads under high temperature load is obtained. The modal damping ratio of the blade is calculated based on the frequency response curves under various operating conditions, and the damping characteristics of the blade damping shroud under different normal pressure loads are analyzed.

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