A frequency measurement device and method for crowned blades with adjustable interface deviation

Abstract

The present invention discloses a frequency measuring device for a blade with a crown and adjustable interface deviation, which relates to the technical field of blade frequency measurement. The measuring device includes a wheel tenon-groove simulation device, a hydraulic force-applying device, a height adjustment device, and a blade crown force simulation device. The height adjustment device adjusts its own height to cause a shape and position deviation in the spatial posture of its top relative to the theoretical position. Two blade crown force simulation parts are used to press the blade crown part of the measured blade from two symmetrical sides. The device allows the relative matching position of the tenon and the tenon to be freely adjusted, so that each matching surface of the tenon and the tenon has a certain initial shape and position deviation during assembly, thereby realizing the measurement of the blade natural frequency under different interface deviation combinations, and can simulate the force state of the blade root and the tenon-groove interface under different rotation speeds, so as to realize the measurement of the blade natural frequency under service status. In addition, the device can simulate the force state of the contact interface at the blade crown under actual service status.

Description

Technical Field

[0001] The invention relates to the technical field of blade frequency measurement, and in particular to a frequency measurement device and method for a crowned blade with adjustable interface deviation. Background Art

[0002] With the continuous development of high-tech in my country, steam turbines play an increasingly important role in the fields of national defense and civil industries such as aviation and shipbuilding. As a representative of advanced manufacturing, the design and manufacturing level of gas turbines has always been one of the important indicators to measure a country's scientific and industrial strength. As one of the core components of gas turbines, the physical and mechanical properties of shrouded blades directly affect the service performance and reliability of the whole machine. Due to the limitations of manufacturing and assembly accuracy, the contact interface between the blade and the disk has random shape and position deviations. The distribution of its processing errors, the tolerance combination caused by the assembly process, and the probability distribution of the change of structural characteristic parameters under working conditions cannot be determined, resulting in a certain discreteness of the natural frequencies of different blades of the shrouded blade-disk system under service conditions.

[0003] Considering the typical thin-walled characteristics of the shrouded blade geometry, its vibration response is very sensitive to changes in boundary conditions. The fluctuation of the natural frequencies of different sectors of the blade-disk structure will lead to the following problems: (1) It causes detuned vibration, causing abnormal friction and wear on the contact surface between the blade and the disk, reducing the life of the blade structure and having a negative impact on the reliability of the engine; (2) It is easy to cause excessive local vibration stress, thereby increasing the risk of engine blade fracture failure; (3) The discreteness of the natural frequencies of different sectors causes the actual frequency of the blade to deviate from the design domain, which may cause the resonance point to fall into the operating speed zone, resulting in abnormal resonance. Therefore, it is crucial to maintain the robustness and consistency of the blade natural frequency. Studying the changes in the blade natural frequency caused by the interface deviation of the tenon connection structure of the shrouded blade-disk system is of great significance for the design and manufacture of high-level gas turbines.

[0004] However, the current dynamic research on shrouded blade-disk structures at home and abroad has not fully considered the structural vibration problem caused by the macroscopic geometric morphology changes of the contact interface at the blade root, and the mapping relationship between the randomness of the interface deformation caused by manufacturing and assembly factors and the discreteness of the vibration characteristics of the blade-disk structure has not been fully established. In order to solve the above problems, it is necessary to carry out the study of the natural frequency of shrouded blades with interface shape and position deviations to achieve the manufacturing and design of high-reliability gas turbines. Summary of the invention

[0005] The object of the present invention is to provide a frequency measurement device and method for a shrouded blade with adjustable interface deviation, so as to solve the problems in the background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A frequency measuring device for a crowned blade with adjustable interface deviation comprises a wheel disc tenon-groove simulation device, a hydraulic force applying device, a height adjusting device and a blade crown force simulation device; the wheel disc tenon-groove simulation device comprises a base, a tenon-groove simulation piece and a support block, the tenon-groove simulation piece is fixed on the base and the middle part of the tenon-groove simulation piece is in a hollow state, and the middle part of the tenon-groove simulation piece extends out of the support block from four sides; the height adjusting device is arranged on the support block, the top of the height adjusting device is used to hold up the root part of the blade to be measured, and the height adjusting device adjusts its own height to make the spatial posture of its top relative to the root part The shape and position deviation occurs in the theoretical position; the hydraulic force-applying device is arranged in the middle hollow part of the mortise and tenon simulation part and is located at the center position of the lower side of the support platform. The hydraulic force-applying device applies an upward load to the height adjustment device and the blade root through the hydraulic pressure, which can simulate the contact force state of the blade root under the action of centrifugal force; the blade crown force simulation device includes two blade crown force simulation parts, and the two blade crown force simulation parts are symmetrically arranged on the top of the mortise and tenon simulation part; the two blade crown force simulation parts are used to press the blade crown part of the measured blade from two symmetrical sides, and the tooth-shaped force surface of the blade crown force simulation parts is added with a spring-pressing part.

[0008] On the basis of the above technical solution, the present invention also provides the following optional technical solution:

[0009] In an optional scheme: the height adjustment device includes a lower support plate and an upper support plate; four threaded barrels are arranged on the upper end surface of the lower support plate near the four corners, threaded rods are screwed into the threaded barrels, and the top of the threaded rods has a groove body; spherical grooves are arranged on the lower end surface of the upper support plate near the four corners, the four spherical grooves correspond to the four threaded rods one by one, and balls that rotate freely therein are installed in the spherical grooves, and the spherical grooves are engaged with the groove bodies of the threaded rods.

[0010] In an optional solution: the threaded barrel has a partial notch toward the outside near the bottom, the lower end of the threaded rod extends to the notch and the threaded rod has a rotating rod, and a nut is provided on the outer wall of each threaded barrel.

[0011] In an optional solution: the threaded rod is also provided with scale lines, and the scale lines are used to record the change in the up and down positions of the four threaded rods.

[0012] In an optional solution: the tooth-shaped stress surface of the blade crown stress simulation part has two spring-loaded parts, and the spring-loaded parts include a fixed cylindrical table, a resisting cylindrical table and a spring. The fixed cylindrical table is arranged on the tooth-shaped stress surface of the blade crown stress simulation part, and mounting holes are arranged on the opposite surfaces of the fixed cylindrical table and the resisting cylindrical table. The two ends of the spring are respectively inserted into the mounting holes of the fixed cylindrical table and the mounting holes of the resisting cylindrical table.

[0013] In an optional solution: a portion of the mortise and tenon simulation component extends out on both sides of the lower end, and the portions extending out on both sides are provided with four threaded holes, and the threaded holes cooperate with fixing bolts to fix the mortise and tenon simulation component on the base.

[0014] In an optional solution: four threaded holes are provided on both blade crown force simulation parts, and the threaded holes cooperate with fixing bolts to fix the blade crown force simulation parts on the tenon and groove simulation parts.

[0015] A frequency measurement method for a shrouded blade with an interface deviation is based on the frequency measurement device for a shrouded blade with an adjustable interface deviation as described above, and the process includes the following steps: Step S1: axially push the measured blade into the tenon of a tenon simulation component so that the bottom of the measured blade contacts the top of a height adjustment device; Step S2: according to experimental requirements, adjust the height of the height adjustment device itself so that the top of the height adjustment device has a shape and position deviation relative to the bottom of the height adjustment device, and then the root of the measured blade contacting the top of the height adjustment device has the same shape and position deviation, simulating the initial interface shape and position deviation of the root tenon of the measured blade relative to the tenon of the tenon simulation component; Step S3: apply a vertically upward load F through a hydraulic force device to make the root tenon of the measured blade contact the tenon simulation component, and as the pressure increases, the matching surface of the root tenon of the measured blade is pressed tightly against the matching surface of the tenon of the tenon simulation component. , simulating the stress state of the tenon connection interface with shape and position deviation under the actual centrifugal force; step S4: installing the spring-pressed part on the tooth-shaped stress surface of the blade crown stress simulation part, and then symmetrically fixing the two blade crown stress simulation parts on the tenon groove simulation part, and pressing the blade crown tooth-shaped surface of the blade to be measured by the spring-pressed part, so as to simulate the contact stress state between adjacent blade crowns under the service state; step S5: placing the acceleration sensor on the side of the blade to be measured, and hitting the side of the blade to be measured with a hammer. The acceleration sensor collects the vibration signal, and the signal processing system performs data analysis to obtain the frequency values ​​of the natural frequencies of each order of the blade; at the same time, observe the height adjustment change of the height adjustment device, and then obtain the corresponding relationship between the deviation value of the tenon interface at the root of the blade to be measured and the corresponding frequency values ​​of each order of the blade; step S6: continue to apply hydraulic pressure through the hydraulic force device, repeat step 5, and the frequencies of each order of the blade under different centrifugal forces can be obtained.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. In the frequency measurement device and method of the crowned blade provided by the present invention, the installation and operation of the height adjustment device are simple and convenient. The spatial height position of the threaded rod in the height adjustment device can be controlled according to the random distribution characteristics of the shape and position deviations generated by the processing and manufacturing of the matching interface at the actual blade root, so as to achieve different interface deviations between the tenon and the tenon groove, thereby well simulating the real interface matching state of the tenon connection structure between the blade root and the wheel disc under service conditions, and having good flexibility.

[0018] 2. In the frequency measurement device and method of the crowned blade provided by the present invention, the spring pressure of the crown force simulation device can simulate the force on the crown contact surface; by changing the spring length and spring stiffness, the force state of the crown tooth contact surface under different service conditions can be simulated, which has high flexibility and operability.

[0019] 3. In the frequency measurement device and method of crowned blades provided by the present invention, the threaded rod in the height adjustment device is provided with a scale. When performing the height adjustment step, the value of the blade interface deviation can be accurately recorded by observing the scale, which has good operability.

[0020] 4. In the frequency measurement device and method of crowned blades provided by the present invention, the vertical load applied to the blade root can be adjusted according to experimental needs to simulate the force effect of centrifugal force on the blade root tenon connection structure at different speeds, which has good flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is an overall schematic diagram of the frequency measuring device of a crowned blade with adjustable interface deviation according to the present invention.

[0022] Figure 2 This is an overall front view of the frequency measuring device for shrouded blades with adjustable interface deviation according to the present invention.

[0023] Figure 3 This is an overall top view of the frequency measuring device for shrouded blades with adjustable interface deviation according to the present invention.

[0024] Figure 4 It is a schematic diagram of the structure of the mortise and tenon simulation component in the present invention.

[0025] Figure 5 It is a front view of the mortise and tenon simulation part in the present invention.

[0026] Figure 6 It is a schematic diagram of the structure of the height adjustment device in the present invention.

[0027] Figure 7 It is a partially enlarged schematic diagram of the height adjustment device in the present invention.

[0028] Figure 8It is a schematic diagram of the installation of the threaded rod in the height adjustment device of the present invention.

[0029] Fig. 9 It is a schematic diagram of the structure of the blade crown simulation component in the present invention.

[0030] Fig.10 It is a schematic diagram of the structure of the elastic pressure member in the present invention.

[0031] Fig.11 Schematic diagram of blade frequency measurement.

[0032] Notes on figure numbers: 1-base, 2-fixing bolt, 3-mortise and tenon simulation part, 4-spring-pressed part, 5-blade crown simulation part, 6-support block, 7-hydraulic force device, 8-lower support plate, 9-upper support plate, 10-threaded cylinder, 11-threaded rod, 12-spherical groove, 13-ball, 14-scale line, 15-nut, 16-rotary rod, 17-threaded hole, 18-1-fixed cylindrical table, 18-2-contact cylindrical table, 18-3-spring, 19-blade to be measured, 20-hammer, 21-signal transmission line, 22-signal processing system, 23-acceleration sensor. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments; in the drawings or descriptions, similar or identical parts use the same reference numerals, and in practical applications, the shape, thickness or height of each component can be enlarged or reduced. The various embodiments listed in the present invention are only used to illustrate the present invention and are not used to limit the scope of the present invention. Any obvious modifications or changes made to the present invention do not depart from the spirit and scope of the present invention.

[0034] In one embodiment, Figure 1-Figure 5As shown, a frequency measuring device for a shrouded blade with adjustable interface deviation comprises a wheel disc tenon-groove simulation device, a hydraulic force applying device 7, a height adjusting device and a blade crown force simulation device; the wheel disc tenon-groove simulation device comprises a base 1, a tenon-groove simulation piece 3 and a support block 6, the tenon-groove simulation piece 3 is fixed on the base 1 and the middle part of the tenon-groove simulation piece 3 is in a hollow state, and the middle part of the tenon-groove simulation piece 3 extends out of the support block 6 from four sides; the height adjusting device is arranged on the support block 6, the top of the height adjusting device is used to hold up the root part of the blade 19 to be measured, and the height adjusting device adjusts the spatial posture of the top 9 of the height adjusting device by adjusting its own height. There is a shape and position deviation relative to the theoretical position; the hydraulic force-applying device 7 is arranged at the middle hollow part of the tenon-groove simulation part 3 and is located at the center position of the lower side of the support platform 6. The hydraulic force-applying device 7 applies an upward load to the height adjustment device and the blade root through hydraulic pressure, which can simulate the contact force state of the blade root under the action of centrifugal force; the blade crown force simulation device includes two blade crown force simulation parts 5, and the two blade crown force simulation parts 5 are symmetrically arranged on the top of the tenon-groove simulation part 3; the two blade crown force simulation parts 5 are used to press the blade crown part of the blade 19 to be tested from two symmetrical sides, and the tooth-shaped force-bearing surface of the blade crown force simulation part 5 is added with a spring-pressing part 4;

[0035] In the embodiment of the present invention, the wheel disk tenon-groove simulation device is used to simulate the connection between the blade root of the actual crowned blade and the wheel disk. The blade 19 to be measured is placed in the tenon in the tenon-groove simulation part 3, and the root part of the blade 19 to be measured is placed on the top of the height adjustment device. The hydraulic force device 7 applies a hydraulic force F vertically upward. When the hydraulic force device 7 contacts the bottom of the height adjustment device, it will gradually lift up the height adjustment device and the blade 19 to be measured, until the blade root tenon of the blade 19 to be measured and the tenon-groove simulation part 3 are gradually pressed; due to the top of the height adjustment device The spatial posture has a shape and position deviation, so that the tenon matching surface of the measured blade 19 and the tenon matching surface of the tenon simulation part 3 have an initial shape and position deviation when they meet, thereby simulating the connection between the tenon and the tenon of the blade root with the shape and position deviation of the contact interface; after the measured blade 19 is installed, the crown tooth surface of the measured blade 19 is pressed by the compression amount of the spring pressure part 4, so that the crown force simulation part 5 and the crown of the measured blade 19 constrain the spatial position to each other, which is used to simulate the contact force caused by the pre-torque between adjacent crowns in the service state. Among them, the hydraulic force device 7 is a hydraulic press, which applies a certain force to the bottom of the measured blade 19 through the hydraulic press to simulate the centrifugal force on the root of the measured blade 19 in the real service state.

[0036] In one embodiment, Figure 1 , Figure 2 , Figure 6 , Figure 7 and Figure 8As shown, the height adjustment device includes a lower support plate 8 and an upper support plate 9; four threaded barrels 10 are arranged near the four corners of the upper end surface of the lower support plate 8, and a threaded rod 11 is screwed into the threaded barrel 10, and the top of the threaded rod 11 has a groove body, and spherical grooves 12 are arranged near the four corners of the lower end surface of the upper support plate 9, and the four spherical grooves 12 correspond to the four threaded rods 11 one by one, and balls 13 that can rotate freely therein are installed in the spherical grooves 12, and the spherical grooves 12 are buckled with the groove body of the threaded rod 11, and the threaded barrel 10 has a part of notch toward the outside near the bottom, and the lower end of the threaded rod 11 extends to the notch and the threaded rod 11 has a rotating rod 16, a nut 15 is provided on the outer wall of each threaded barrel 1; in the embodiment of the present invention, before measuring the frequency experiment, the rotating rods 16 at the bottom ends of the four threaded rods 11 are rotated respectively to adjust the feed amount of the threaded rods 11, so as to adjust the height and angle of the upper support plate 9 relative to the lower support plate 8, so that the support plate 9 has a shape and position deviation relative to the lower support plate 8; and then the spatial posture of the support plate 9 has a shape and position deviation, so that the tenon matching surface of the measured blade 19 and the tenon matching surface of the tenon simulation part 3 have an initial shape and position deviation when they are connected; the shape and position deviation depends on the spatial height relationship between the four threaded rods 11. After the adjustment is completed, tighten the nut 15 to prevent loosening during the experiment. The threaded rod 11 is also provided with a scale line 14, which is used to record the change in the upper and lower positions of the four threaded rods 11, and then obtain the corresponding relationship between the tenon interface deviation value at the root of the measured blade 19 and the corresponding blade frequency values ​​of each order.

[0037] In one embodiment, as shown in FIG. Fig. 9 and Fig.10 As shown, there are two spring-pressing parts 4 on the tooth-shaped force surface of the blade crown force simulation part 5, and the spring-pressing parts 4 include a fixed cylindrical table 18-1, a resisting cylindrical table 18-2 and a spring 18-3. The fixed cylindrical table 18-1 is arranged on the tooth-shaped force surface of the blade crown force simulation part 5, and mounting holes are arranged on the opposite surfaces of the fixed cylindrical table 18-1 and the resisting cylindrical table 18-2. The two ends of the spring 18-3 are respectively inserted into the mounting holes of the fixed cylindrical table 18-1 and the mounting holes of the resisting cylindrical table 18-2; in an embodiment of the present invention, after the installation of the measured blade 19 is completed, the compression amount of the spring 18-3 is used to press the blade crown tooth-shaped surface of the measured blade 19, so that the blade crown force simulation part 5 and the blade crown of the measured blade 19 constrain each other in spatial position, which is used to simulate the contact force caused by the pre-torque between adjacent blade crowns in the service state.

[0038] In one embodiment, Figure 1 , Figure 3 and Figure 4 As shown, a portion of the mortise and tenon simulation component 3 extends out on both sides of the lower end, and the portions extending out on both sides are provided with four threaded holes 17 , and the threaded holes 17 cooperate with fixing bolts to fix the mortise and tenon simulation component 3 on the base 1 .

[0039] In one embodiment, Figure 1 , Figure 2 and Fig. 9 As shown, four threaded holes 17 are provided on the two blade crown force simulation parts 5 , and the threaded holes 17 cooperate with the fixing bolts 2 to fix the blade crown force simulation parts 5 on the tenon-groove simulation parts 3 .

[0040] In one embodiment, Figure 7 As shown, based on the device in the above embodiment, a frequency measurement method of a shrouded blade with interface deviation is proposed, and the process includes the following steps:

[0041] Step S1: Push the measured blade 10 axially into the tenon of the tenon simulation part 3, so that the bottom of the measured blade 19 contacts the top of the height adjustment device; in this step, the bottom of the measured blade 19 contacts the upper support plate 9 in the height adjustment device;

[0042] Step S2: According to the experimental requirements, the height of the height adjustment device itself is adjusted so that the top of the height adjustment device produces a shape and position deviation relative to the bottom of the height adjustment device, and then the root of the measured blade 19 in contact with the top of the height adjustment device has the same shape and position deviation, simulating the initial interface shape and position deviation of the root tenon of the measured blade 19 relative to the tenon groove of the tenon groove simulation part 3; in this step, the specific operation is: rotate the rotating rod 16 at the lower part of the threaded rod 11 to change the feed amount of the threaded rod 11, so as to adjust the height and angle of the upper support plate 9 relative to the lower support plate 8, so that the support plate 9 produces a shape and position deviation relative to the lower support plate 8, so that the root of the measured blade 19 at the connection with the upper support plate 9 has the same shape and position deviation, simulating the initial interface shape and position deviation of the root tenon relative to the tenon groove, and tighten the nuts 15 on the four threaded barrels 10 after adjustment;

[0043] Step S3: applying a load F in a vertical upward direction through the hydraulic force applying device 7, so that the blade root tenon of the blade 19 to be tested contacts the tenon-groove simulation part 3. As the pressure increases, the matching surface of the blade root tenon of the blade 19 to be tested and the matching surface of the tenon-groove simulation part 3 are pressed tightly, simulating the actual stress state of the tenon connection interface with shape and position deviation under the action of centrifugal force;

[0044] Step S4: installing the spring-pressing member 4 on the tooth-shaped stress-bearing surface of the blade crown stress-bearing simulation member 5, and then symmetrically fixing the two blade crown stress-bearing simulation members 5 on the tenon-groove simulation member 3, and pressing the blade crown tooth-shaped surface of the blade 19 to be tested by the spring-pressing member, thereby simulating the contact stress state between adjacent blade crowns in the service state; the specific operation of this step is to install the blade crown stress-bearing simulation member 5 on the spring-pressing member 4 and then fix it on the tenon-groove simulation member 3 by the fixing bolt 2, and make the contact cylindrical platform 18-2 press the blade crown tooth-shaped surface of the blade 19 to be tested by the contraction of the spring 18-3, thereby simulating the contact stress state between adjacent blade crowns in the service state;

[0045] Step S5: placing the acceleration sensor 23 on the side of the measured blade 19, and hitting the side of the measured blade 19 with a hammer 20, the acceleration sensor 23 collects the vibration signal, and the vibration signal is transmitted to the signal processing system 22 by the signal transmission line 21, and the signal processing system 22 performs data analysis to obtain the frequency values ​​of each order of the blade's natural frequency; at the same time, observing the scale line 14 on the threaded rod 11, recording the change in the upper and lower positions of the four threaded rods 11, and then obtaining the corresponding relationship between the tenon interface deviation value at the root of the measured blade 19 and the corresponding frequency values ​​of each order of the blade;

[0046] Step S6: Continue to apply hydraulic pressure through the hydraulic force applying device 7 and repeat step 5 to obtain the frequencies of the blades under different centrifugal forces.

[0047] It should be noted that, considering the randomness of the shape and position deviation of the actual contact interface at the blade root, according to specific experimental requirements, the rotating rod 16 at the bottom of the rotating threaded rod 11 can be freely adjusted so that the relative spatial posture between the lower support plate 8 and the upper support plate 9 can be changed arbitrarily, thereby realizing a random shape and position deviation combination between the tenon matching interface and the mortise matching interface of the blade root.

[0048] The above is only a specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A frequency measuring device for blades with shrouds and adjustable interface deviations, comprising a wheel mortise and tenon simulation device, a hydraulic force application device, a height adjustment device and a blade shroud force simulation device, characterized in that: The wheel disc tenon-groove simulation device comprises a base, a tenon-groove simulation piece and a support block; The mortise and tenon simulation piece is fixed on the base and the middle part of the mortise and tenon simulation piece is in a hollow state, and the middle part of the mortise and tenon simulation piece extends out support blocks from four sides; The height adjustment device is arranged on the support block, and the top of the height adjustment device is used to hold up the root part of the blade to be measured. The height adjustment device adjusts its own height to make the spatial posture of the top of the height adjustment device have shape and position deviation relative to the theoretical position. The hydraulic force applying device is arranged at the hollowed-out middle part of the mortise and tenon simulation part and is located at the center of the lower side of the support platform. The hydraulic force applying device applies an upward load to the height adjustment device and the blade root through hydraulic pressure, simulating the contact force state of the blade root under the action of centrifugal force. The blade crown force simulation device comprises two blade crown force simulation pieces, and the two blade crown force simulation pieces are symmetrically arranged on the top of the tenon-groove simulation piece; The two blade crown force simulation parts are used to press the blade crown part of the blade to be tested from two symmetrical sides, and the tooth-shaped force-bearing surfaces of the blade crown force simulation parts are added with spring-pressing parts; The frequency measuring device also includes an acceleration sensor and a force hammer. The acceleration sensor is arranged on the side of the measured blade and is used to collect vibration signals. The force hammer is used to strike the measured blade to stimulate vibration. The vibration signal is analyzed by a signal processing system to obtain the blade's natural frequency.

2. The frequency measuring device for shrouded blades with adjustable interface deviation according to claim 1 is characterized in that: The height adjustment device comprises a lower support plate and an upper support plate; The upper surface of the lower support plate is provided with four threaded barrels near the four corners, threaded rods are screwed into the threaded barrels, and the tops of the threaded rods are provided with grooves; The lower end surface of the upper support plate is provided with spherical grooves near the four corners, the four spherical grooves correspond to the four threaded rods one by one, balls are installed in the spherical grooves and rotate freely therein, and the spherical grooves are buckled together with the groove bodies of the threaded rods.

3. The frequency measuring device for shrouded blades with adjustable interface deviation according to claim 2 is characterized in that: The threaded barrel has a partial notch toward the outside near the bottom, the lower end of the threaded rod extends to the notch and the threaded rod has a rotating rod, and a nut is arranged on the outer wall of each threaded barrel.

4. The frequency measuring device for shrouded blades with adjustable interface deviation according to claim 2 is characterized in that: The threaded rods are also provided with scale lines, which are used to record the vertical position changes of the four threaded rods.

5. The frequency measuring device for shrouded blades with adjustable interface deviation according to claim 1 is characterized in that: The tooth-shaped stress-bearing surface of the blade crown stress-bearing simulation part has two elastic pressure parts; The elastic pressure member includes a fixed cylindrical platform, an abutting cylindrical platform and a spring; The fixed cylindrical platform is arranged on the tooth-shaped stress surface of the blade crown stress simulation component. The fixed cylindrical platform and the resisting cylindrical platform are provided with mounting holes on the opposite surfaces. The two ends of the spring are respectively inserted into the mounting holes of the fixed cylindrical platform and the mounting holes of the resisting cylindrical platform.

6. The frequency measuring device for shrouded blades with adjustable interface deviation according to claim 1 is characterized in that: A portion of the mortise and tenon simulation piece extends out from both sides of the lower end, and the portions extending out from both sides are provided with four threaded holes, and the threaded holes cooperate with fixing bolts to fix the mortise and tenon simulation piece on the base.

7. The frequency measuring device for shrouded blades with adjustable interface deviation according to claim 5, characterized in that: Four threaded holes are arranged on the two blade crown force simulation parts, and the threaded holes cooperate with fixing bolts to fix the blade crown force simulation parts on the tenon and groove simulation parts.

8. A frequency measurement method for a shrouded blade with adjustable interface deviation, characterized in that: Based on the frequency measuring device of a shrouded blade with adjustable interface deviation according to any one of claims 1 to 7, the measuring method comprises the following steps: Step S1: Push the blade to be measured axially into the tenon of the tenon simulation component so that the bottom of the blade to be measured contacts the top of the height adjustment device; Step S2: According to the experimental requirements, the height of the height adjustment device is adjusted so that the top of the height adjustment device has a shape and position deviation relative to the bottom of the height adjustment device, and then the blade root of the blade under test contacting the top of the height adjustment device has the same shape and position deviation, simulating the initial interface shape and position deviation of the blade root tenon of the blade under test relative to the tenon groove of the tenon groove simulation part; Step S3: applying a load F in a vertical upward direction through a hydraulic force applying device, so that the blade root tenon of the blade under test contacts with the tenon-groove simulation part. As the pressure increases, the matching surface of the blade root tenon of the blade under test and the matching surface of the tenon-groove simulation part are pressed tightly, simulating the actual stress state of the tenon connection interface with shape and position deviation under the action of centrifugal force; Step S4: installing the spring-pressing member on the tooth-shaped stress-bearing surface of the blade crown stress-bearing simulation member, and then symmetrically fixing the two blade crown stress-bearing simulation members on the tenon-groove simulation member, and pressing the blade crown tooth-shaped surface of the blade to be tested by the spring-pressing member, thereby simulating the contact stress state between adjacent blade crowns in the service state; Step S5: placing an acceleration sensor on the side of the measured blade, hitting the side of the measured blade with a hammer, collecting vibration signals from the acceleration sensor, performing data analysis through a signal processing system, and obtaining the frequency values ​​of each order of natural frequencies of the blade; at the same time, observing the height adjustment change of the height adjustment device, and then obtaining the corresponding relationship between the tenon interface deviation value at the root of the measured blade and the corresponding frequency values ​​of each order of the blade; Step S6: Continue to apply hydraulic pressure through the hydraulic force applying device and repeat step S5 to obtain the frequencies of the blades under different centrifugal forces.

Images