Non-contact vibration measurement device and method for rotating blades of an entire engine

Abstract

The present invention discloses a non-contact vibration measurement device for rotating blades of an entire engine. The device comprises a rotational speed synchronization sensor disposed axially through an intake casing and a guide vane support, with the monitoring probe of the sensor disposed facing the rotating blade disk. A groove is provided on the end face of the rotating blade disk at a position corresponding to the monitoring probe of the rotational speed synchronization sensor. Simultaneously, a plurality of blade tip timing sensors are disposed on the axial flow casing at circumferential positions corresponding to the radial direction of the rotating blade disk. The present invention achieves effective measurement of rotational speed synchronization signals in an entire engine environment, and combines this with reliable placement, reasonable installation, and rapid assembly and disassembly of blade tip timing sensors to achieve non-contact vibration measurement of rotating blades at all levels within the entire engine, ensuring that the collected non-contact vibration measurement signals of the rotating blades have a good signal-to-noise ratio, thereby providing a simple and convenient online monitoring method for accurately identifying the engine order vibration mode of interest.

Description

Technical Field

[0001] The present invention relates to the technical field of vibration monitoring of rotating blades of an aero-engine, and in particular to a non-contact vibration measuring device and method for rotating blades of an entire engine. Background Art

[0002] Non-contact vibration measurement of engine rotating blades is an important means of obtaining the vibration characteristics and loads borne by rotating blades. It provides technical support for vibration design, strength assessment, life prediction, and fault diagnosis of rotating blades, and is crucial for ensuring the structural integrity and reliability of engines. Based on the principle of blade tip timing, non-contact vibration measurement of rotating blades uses an undersampled signal. Because the blade vibration sampling frequency is the product of the number of sensors and the rotational frequency, the blade vibration frequency is typically higher than the rotational frequency. The number of sensors installed on the casing is limited, so the tip timing signal is undersampled. Signal processing methods can be used to process this undersampled signal to obtain vibration parameters related to the rotating blades.

[0003] However, because non-contact vibration measurement of rotating blades requires a speed synchronization sensor to be installed near and aligned with the rotor to obtain the speed reference of one pulse per revolution required for non-contact vibration measurement of rotating blades, existing non-contact vibration measurement of rotating blades is only suitable for situations where the rotor shaft is always partially exposed. For example, in non-contact vibration measurement of rotating blades in compressor components, the speed synchronization sensor can be conveniently installed on the partially exposed compressor shaft. However, for the entire engine, since the engine rotor shaft is completely enclosed within the engine, if the speed synchronization sensor is radially arranged near the shaft through the casing, it will be blocked by the double-layer casing, the high operating temperature limit inside the engine, and interference from other components including the blades. This makes the installation of the speed synchronization sensor in the entire engine difficult, and there has been no effective solution. Ultimately, non-contact vibration measurement methods for rotating blades have been unable to be implemented in vibration testing of rotating blades within the entire engine. Furthermore, according to existing public information, no related methods or devices for non-contact vibration measurement of rotating blades in an entire engine have been disclosed. Summary of the Invention

[0004] The purpose of the present invention is to provide a device that can realize the effective measurement of the speed synchronization signal and non-contact vibration measurement of the rotating blades in the environment of the entire engine. The device not only ensures that the collected non-contact vibration measurement signal of the rotating blade has a good signal-to-noise ratio, but also ensures the reliable installation and rapid assembly and disassembly of the blade tip timing sensor in the environment of the entire engine, thereby being able to quickly, conveniently and accurately identify the engine order vibration mode of interest.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A non-contact vibration measuring device for rotating blades of an entire engine, comprising: a rotating blade disk disposed in an axial flow casing, a guide vane support in contact with the rotating blade disk via grate teeth, and an intake casing integrally fixed to the guide vane support;

[0007] A speed synchronization sensor is provided axially through the air intake casing and the guide vane support, and a monitoring probe of the speed synchronization sensor is provided in a direction facing the rotating blade disk;

[0008] A groove is provided on the end face of the rotating blade disk at a position corresponding to the monitoring probe of the speed synchronization sensor;

[0009] A plurality of blade tip timing sensors are arranged on the axial flow casing at circumferential positions corresponding to the radial direction of the rotating blade disk;

[0010] The installation angles of the blade tip timing sensors when arranged circumferentially in the axial flow casing are based on ensuring that each blade tip timing sensor can measure a good vibration response under the first 10 rotor excitations and the airflow excitations caused by the front and rear stator blades and support plates of the blade being measured, and are determined by calculation using the sensor position optimization layout software;

[0011] The blade tip timing sensor is fixed on the axial flow casing through a sensor mounting base;

[0012] The sensor mounting base is provided with a stepped through hole for mounting the blade tip timing sensor, and the outer side of the sensor mounting base is provided with a thread. The blade tip timing sensor is inserted into the stepped through hole of the sensor mounting base after passing through a fixing nut and an elastic gasket in sequence;

[0013] By screwing the fixing nut, both sides of the elastic gasket will contact the outer end surface of the sensor mounting seat and the inner end surface of the fixing nut respectively;

[0014] The air intake casing is provided with a plurality of long bolts for fixing squirrel cage springs, and the squirrel cage springs support and fix the gas generator rotor with the rotating blade disk on the air intake casing;

[0015] The speed synchronization sensor is installed and fixed by replacing one of the long bolts;

[0016] A through hole is provided at a position corresponding to the speed synchronization sensor installed on the guide vane support;

[0017] The front end outer peripheral surface of the speed synchronization sensor is provided with a thread, and the speed synchronization sensor passes through the mounting hole of the squirrel cage spring support and the through hole of the air intake casing in sequence and is threadedly connected to the guide vane support.

[0018] As a further improvement of the present invention, the number of the blade tip timing sensors arranged on the circumferential position of the axial flow casing is 4 to 8.

[0019] As a further improvement of the present invention, the rotational speed synchronization sensor includes a magnetoelectric rotational speed sensor or a photoelectric rotational speed sensor.

[0020] As a further improvement of the present invention, the blade tip timing sensor includes an optical fiber sensor, an eddy current sensor or a capacitive sensor.

[0021] The present invention further provides a non-contact vibration measurement method for rotating blades of an entire engine. The vibration measurement method is performed on any of the aforementioned non-contact vibration measurement devices for rotating blades of an entire engine, wherein the vibration measurement method comprises:

[0022] The speed synchronization sensor is used to measure the interval between two adjacent key phase pulses to determine the time Tn taken for the rotating blade disk to rotate one circle and the speed of the gas generator rotor;

[0023] The order in which the blades pass through the blade tip timing sensor is determined according to the relative positions of the blades on the rotating blade disk and the speed synchronization sensor, thereby determining the number b of each blade;

[0024] Based on the rotational speed of the gas generator rotor and the determined number b of each blade, the theoretical arrival time t of each blade passing the blade tip timing sensor when the blade is not vibrating is determined based on the key phase pulse of the rotational speed synchronization sensor. nbs0 and the actual arrival time t of each blade passing the blade tip timing sensor when vibrating nbs ;

[0025] According to the theoretical arrival time t nbs0 , the actual arrival time t nbs The time Tn taken for the rotating blade disk to rotate one circle is combined with the distance from the tip of the blade on the rotating blade disk to the disk center to determine the vibration displacement of each blade.

[0026] As a further improvement of the present invention, the theoretical arrival time t nbs0 , the actual arrival time t nbs The time Tn taken for the rotating blade disk to rotate one circle, combined with the distance from the blade tip to the disk center of the rotating blade disk, is used to determine the vibration displacement of each blade. The calculation formula is as follows:

[0027] ;

[0028] Where, The distance from the tip of the blade to the center of the rotating blade disk; is the actual arrival time of the blade; is the theoretical arrival time of the blade; The time it takes for the impeller to make one rotation; is the blade vibration displacement; Indicates the current lap number; subscript is the leaf number; subscript The number of the blade tip timing sensor.

[0029] As a further improvement of the present invention, the method further comprises:

[0030] The vibration measurement method is continuously tested by each blade tip timing sensor during the entire rotation speed push-up or pull-down process to obtain the blade tip amplitude curve of each blade.

[0031] As a further improvement of the present invention, the method further comprises:

[0032] According to the blade tip amplitude curve, the vibration parameters of each blade are obtained through single degree of freedom fitting and circumferential Fourier transform; the vibration parameters include: vibration frequency, vibration amplitude, resonant speed, phase, excitation order, modal order and modal damping.

[0033] As a further improvement of the present invention, the method further comprises:

[0034] The vibration stress distribution and the relationship between the blade tip amplitude and the vibration stress of each blade under the excitation order of interest are calculated or calibrated to obtain the calibration relationship between the blade tip amplitude and the vibration stress of each blade under each excitation order. The vibration stress of the maximum stress point of each blade under each excitation order is calculated in combination with the vibration displacement of each blade.

[0035] Technical effects and advantages of the present invention:

[0036] The present invention provides a non-contact vibration measurement device for rotating blades of an entire engine. The device comprises a rotational speed synchronization sensor axially extending through the intake casing and the guide vane support, with the monitoring probe of the rotational speed synchronization sensor positioned facing the rotating blade disk. A groove is provided on the end face of the rotating blade disk at a position corresponding to the monitoring probe of the rotational speed synchronization sensor. Furthermore, a plurality of blade tip timing sensors are arranged on the axial flow casing at circumferential positions corresponding to the radial direction of the rotating blade disk. The present invention measures the moment when a rotating blade within the entire engine reaches the blade tip timing sensor based on the blade tip timing principle, converts the measured time pulse signal into a blade tip amplitude signal, and further extracts the vibration parameters of the rotating blades of the entire engine through a blade tip timing signal parameter identification method, thereby providing a basis for vibration evaluation, life assessment, fault diagnosis, and improved design of the rotating blades within the entire engine. The present invention realizes the effective measurement of the speed synchronization signal in the engine whole machine environment, and combines it with the reliable layout position selection, reasonable installation and rapid assembly and disassembly of the blade tip timing sensor, thereby realizing the non-contact vibration measurement of the rotating blades at all levels in the engine whole machine, ensuring that the collected non-contact vibration measurement signal of the rotating blade has a good signal-to-noise ratio, thereby providing a simple, convenient and effective online monitoring means for the accurate identification of the engine order vibration mode of concern.

[0037] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the overall structure of the non-contact vibration measuring device for rotating blades of an entire engine according to the present invention;

[0039] Figure 2 for Figure 1 Schematic diagram of the structure after the cross section along AA;

[0040] Figure 3 for Figure 2 Schematic diagram of the structure after the cross section along BB;

[0041] Figure 4 for Figure 2 5:1 magnified image of the local structure at point C in the middle.

[0042] Figure numerals: 1—intake casing; 2—guide vane support; 3—rotating blade disk; 30—blade; 31—groove; 4—power turbine shaft; 5—squirrel cage spring support; 6—bearing; 7—bevel gear; 8—locking nut; 9—speed synchronization sensor; 10—long bolt; 11—axial flow casing; 110—sensor mounting seat; 12—blade tip timing sensor; 13—elastic gasket; 14—fixing nut. DETAILED DESCRIPTION

[0043] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0044] Based on the blade tip timing principle underlying non-contact vibration measurement of rotating blades described above, it is clear that the acquisition of a speed synchronization signal (i.e., a speed synchronization reference of one pulse per revolution) is crucial for non-contact vibration measurement of rotating blades and is a crucial step in blade vibration analysis. If the speed synchronization sensor fails, the entire blade tip timing system will cease to function. In the prior art, the engine rotor speed signal can be obtained from a tone wheel on an accessory gear. This is a non-integer multiple of the rotor speed. The rotor speed can be calculated by converting the transmission ratio, which does not affect the speed counting and display. However, this speed cannot be used as a key phase signal for non-contact vibration measurement of rotating blades, as it does not meet the speed reference requirement of one pulse per revolution. Therefore, in actual measurement, the speed synchronization sensor must be installed near the rotating shaft. The speed reference is acquired by machining a groove or spraying black paint on the shaft, and then aligning the speed synchronization sensor with the shaft groove or painted black paint. Therefore, the implementation of this process requires that a portion of the rotor shaft be exposed to the outside, so that the speed synchronization sensor can align with the shaft to obtain the speed synchronization signal. Therefore, existing non-contact vibration measurement of rotating blades can only be used for compressor component test pieces. As for the rotating blades of the entire engine, the speed synchronization sensor is difficult to install because the entire shaft is completely enclosed inside the engine, coupled with the double-layer casing barrier, the high temperature limit inside the engine, and interference from other accessories including the blades. Therefore, the existing non-contact vibration measurement of rotating blades based on the speed synchronization benchmark is difficult to use for vibration monitoring of the rotor blades of the entire engine.

[0045] The present invention aims to solve the problem that the existing non-contact vibration measurement of rotating blades of the engine as a whole cannot be implemented because the speed synchronization sensor cannot be effectively installed. An improved non-contact vibration measurement method of rotating blades of the engine as a whole is proposed, and a corresponding test device is designed to achieve effective measurement of the speed synchronization signal in the engine as a whole environment. The method is combined with the reliable layout position selection, reasonable installation and rapid assembly and disassembly of the tip timing sensor to achieve non-contact vibration measurement of rotating blades at all levels in the engine as a whole. At the same time, it also ensures that the collected non-contact vibration measurement signal of the rotating blades has a good signal-to-noise ratio, thereby providing a simple, convenient and effective online monitoring means for accurate identification of the engine order vibration mode of concern.

[0046] For details, please refer to Figure 1 and combined Figure 2 As shown, the non-contact vibration measuring device for the rotating blades of the entire engine provided by the present invention comprises at least: a rotating blade disk 3 arranged in the axial flow casing 11, a guide vane support 2 in contact with the rotating blade disk 3 through the grate teeth, and an intake casing 1 fixed to the guide vane support 2; wherein, the guide vane support 2 connects the intake casing 1 and the axial flow casing 11 to form a gas flow path. In order to accurately obtain the speed signal of the entire engine rotor as a speed reference condition, the present invention sets a speed synchronization sensor 9 axially penetrating the intake casing 1 and the guide vane support 2, and sets the monitoring probe of the speed synchronization sensor 9 in the direction facing the rotating blade disk 3; at the same time, a groove 31 is provided on the end disk edge of the rotating blade disk 3 at a position corresponding to the monitoring probe of the speed synchronization sensor 9. For details, please refer to Figure 4 As shown in the figure, in this way, the speed synchronization signal with one pulse per revolution can be accurately obtained. Figure 2 and combined Figure 3As shown, the present invention further provides a plurality of blade tip timing sensors 12 at circumferential positions on the axial flow casing 11 corresponding to the radial direction of the rotating blade disk 3 (those skilled in the art will readily appreciate that the blade tip timing sensors 12 need to be arranged within the chord length of the corresponding blade 30 on the rotating blade disk 3 to be measured, to ensure that the sensors can effectively monitor the rotation process of each blade 30). Furthermore, the speed synchronization sensor 9 first measures the interval between two adjacent key phase pulses to determine the time Tn taken for one rotation of the rotating blade disk 3 and the speed of the gas generator rotor; then, based on the relative positions of the blades 30 on the rotating blade disk 3 and the speed synchronization sensor 9, the order in which the blades 30 successively pass through the blade tip timing sensors 12 is determined, thereby determining the number b of each blade 30; and then, based on the speed of the gas generator rotor and the determined number b of each blade 30, the key phase pulse of the speed synchronization sensor 9 is used as a reference to determine the theoretical arrival time t of each blade 30 passing through the blade tip timing sensor 12 when the blade 30 is not vibrating. nbs0 and the actual arrival time t of each blade 30 passing the blade tip timing sensor 12 when vibrating nbs Finally, we can determine the theoretical arrival time t nbs0 , actual arrival time t nbs The time Tn required for the rotating blade disk 3 to complete one rotation is combined with the distance from the tip of the blade 30 on the rotating blade disk 3 to the disk center (i.e., the impeller radius) to ultimately determine the vibration displacement of each blade 30. This enables non-contact vibration measurement of the rotating blades of the entire engine.

[0047] For details, see Figure 2 As shown, it is necessary to explain that the air intake casing 1 is also provided with components such as a power turbine shaft 4, a squirrel cage spring support 5, a bearing 6, a bevel gear 7, a locking nut 8 and a long bolt 10; wherein, the attachment provided in this embodiment Figure 2 The rotating blade disk 3 shown in the figure is actually the first-stage blade disk. After being connected with the other stages of blade disks and the gas turbine disk through the arc end teeth, the first-stage blade disk is axially tightened to form the gas generator rotor. The power turbine shaft 4 connected to the power turbine disk passes through the gas generator rotor to output shaft power. The front journal of the first-stage blade disk 3 is mounted on the squirrel cage spring 5 through the bearing 6. The squirrel cage spring 5 is used to support and fix the gas generator rotor with the rotating blade disk 3 on the intake casing 1. The squirrel cage spring 5 is fixed to the mounting seat of the intake casing 1 through the long bolt 10. The long bolt 10 passes through the through hole of the intake casing 1 and is threadedly connected to the guide vane support 2. The bevel gear 7 is fixed to the axial direction of the first-stage blade disk through the locking nut 8. The bevel gear 7 and the first-stage blade disk drive the accessory transmission system through the gear. Through the above detailed description of the distribution position of each component inside the engine, please refer to the following Figure 2It is not difficult to see that the space around the shaft of the gas generator rotor in the whole machine has been completely filled with existing components, and there is no exposed part, which can be used for the effective installation of the speed synchronization sensor. Therefore, if Figure 2 The present invention is the first to install the speed synchronization sensor 9 in a manner of axially penetrating the air intake casing 1 and the guide vane support 2, and to provide a groove 31 at the corresponding position of the rotating blade disk 3 (see FIG. Figure 4 ), to achieve real-time acquisition of the rotor speed synchronization signal, thereby ensuring the accurate measurement of the speed synchronization benchmark of one pulse per revolution, and thus creating the necessary working conditions for the effective operation of the subsequent blade tip timing system.

[0048] Specifically, in the embodiment provided by the present invention, since the squirrel cage spring support 5 is fixed to the mounting seat of the air intake casing 1 by a plurality of symmetrically distributed long bolts 10, as shown in FIG. Figure 2 As shown, in the present invention, the installation position of one of the long bolts 10 can be used to install a speed synchronization sensor 9 for measuring the speed of the gas generator rotor, generating the pulse signal required for non-contact vibration measurement of the blades 30 (a key phase signal with a 0-5V standard TTL level and a pulse falling edge width of only 0.5 microseconds is generated for each revolution of the gas generator rotor). It is necessary to point out that replacing one of the long bolts 10 with the speed synchronization sensor 9 will not affect the installation tightness of the squirrel cage spring support 5 or the support stiffness of the rotor in the short-term non-contact vibration measurement of the rotating blades of the entire machine. At the same time, a through hole is provided at the corresponding position of the speed synchronization sensor 9 on the guide vane support 2. For details, please refer to Figure 4 As shown, by providing threads on the outer circumference of the front end of the speed synchronization sensor 9, the speed synchronization sensor 9 is threadedly inserted into the through-hole of the guide vane support 2 through the mounting hole of the squirrel cage spring support 5, the through-hole of the air intake casing 1, and the guide vane support 2. This allows the speed synchronization sensor 9 to be inserted into the through-hole of the guide vane support 2 and positioned, thus completing the portable installation of the speed synchronization sensor 9. In addition, a gap is left between the speed synchronization sensor 9 and the end face of the first-stage blade disk. A groove 31 is provided at the edge of the end face of the first-stage blade disk. When the gas generator rotor rotates, the groove 31 at the end face of the first-stage blade disk will pass through the speed synchronization sensor 9 once per revolution, thereby generating a speed synchronization signal that serves as the key phase signal for the non-contact vibration measurement of the blades 30.

[0049] Furthermore, the blade tip timing sensor 12 can be fixed on the axial flow casing 11 through the sensor mounting seat 110. There are multiple sensor mounting seats 110 with uneven circumferential distribution on the axial flow casing 11. The blade tip timing sensor 12 is installed in the sensor mounting seat 110. When measuring the vibration condition of the corresponding blade 30 on the first-stage blade disk, the blade tip timing sensor 12 needs to be set facing the blade tip of the blade 30 of the first-stage blade disk; similarly, if the vibration condition of the corresponding blade 30 on the second-stage blade disk is measured, it is only necessary to arrange the blade tip timing sensor 12 at a position facing the blade tip of the second-stage blade disk. Similarly, it is only necessary to move the blade tip timing sensor 12 to the corresponding position in the axial direction of the axial flow casing 11 to achieve real-time and effective monitoring of the vibration condition of the corresponding blade 30 on the rotating blade disk 3 at each level.

[0050] Furthermore, the circumferential mounting position of the sensor mounting base 110 on the axial flow casing 11 can be calculated and determined by the sensor position optimization layout software. This calculation process must comprehensively consider the degree of identifiable resonance modes of the blade 30 and the available mounting space outside the intake casing 1 (to avoid interference from external piping and other accessories). Specifically, the installation angle of the blade tip timing sensors 12 when arranged circumferentially on the axial flow casing 11 should be determined by the sensor position optimization layout software based on ensuring that each blade tip timing sensor 12 can obtain a good vibration response under the first 10 rotor excitations and the airflow excitation caused by the stator blades and support plates before and after the blade being measured.

[0051] Furthermore, the number of blade tip timing sensors 12 arranged around the circumference of the axial flow casing 11 is preferably 4 to 8. This is to ensure that each vibration order of interest to the engine has at least four different response angles. Furthermore, due to limitations on the measurement area, measurement costs, and the potential negative impacts of casing modification, such as casing deformation and air leakage, the number of sensors arranged on the axial flow casing generally does not exceed 8.

[0052] Furthermore, the sensor mounting base 110 has a stepped through-hole for mounting the blade tip timing sensor 12. The stepped through-hole allows the optical signal to pass normally while radially positioning the blade tip timing sensor 12, ensuring that the distance between the blade tip timing sensor 12 and the blade 30 is within the optimal measurement range. At the same time, the blade tip timing sensor 12 will not fall into the axial flow casing 11 and damage the blade 30, causing an accident. The sensor mounting base 110 has threads on its outer side. The blade tip timing sensor 12 passes through the fixing nut 14 and the elastic gasket 13, and then is inserted into the stepped through-hole inside the sensor mounting base 110. By tightening the fixing nut 14 through the threads, the elastic gasket 13 contacts the outer end surface of the sensor mounting base 110 and the inner end surface of the fixing nut 14, respectively, and is compressed and deformed, thereby retaining the blade tip timing sensor 12. This prevents the blade tip timing sensor 12 from shaking or loosening during the vibration measurement of the blade 30, ensuring the safety of the test and the stability, reliability, and high signal-to-noise ratio of the test signal. When the elastic gasket 13 is not compressed, it can return to its normal state, facilitating normal disassembly of the blade tip timing sensor 12 .

[0053] The present invention measures the moment when the rotating blades of the entire engine reach the tip timing sensor 12 based on the tip timing principle by radially installing unevenly distributed tip timing sensors 12 on the axial flow casing 11 and a speed synchronization sensor 9 axially installed in the mounting seat of the intake casing 1 facing the end disk edge of the first-stage blade disk, and converts the measured time pulse signal into a tip amplitude signal. Further, through the tip timing signal parameter identification method, the vibration parameters of the rotating blades of the entire engine are extracted, thereby providing a basis for vibration evaluation, life assessment, fault diagnosis and improved design of the entire rotating blades of the engine.

[0054] The specific testing method of the non-contact vibration measuring device for rotating blades of an entire engine provided by the present invention is described in detail below:

[0055] 1. Determine Tn and the speed of the gas generator rotor at that time by measuring the interval between two adjacent key phase pulses from the speed synchronization sensor 9. Determine the order in which each blade 30 passes the blade tip timing sensor 12, i.e., the number of each blade 30, by measuring the relative position of the blades 30 on the rotating blade disk 3 and the speed synchronization sensor 9.

[0056] 2. Based on the measured speed and the determined number of the blade 30, the theoretical arrival time t of each blade 30 passing the blade tip timing sensor 12 when it is not vibrating can be determined based on the key phase pulse of the speed synchronization sensor 9. nbs0 ;

[0057] 3. Based on the key phase pulse of the speed synchronization sensor 9, the actual arrival time t of each blade 30 passing through the blade tip timing sensor 12 when vibrating is measured by the blade tip timing sensor 12. nbs ;

[0058] 4. The vibration displacement of each blade 30 can be calculated using the calculation formula 1 below, combined with the impeller radius and the parameters obtained above.

[0059] ; (1)

[0060] Where, is the impeller radius (i.e., the distance from the tip of the blade to the center of the rotating blade disk), in mm; is the actual arrival time of the blade, in seconds; is the theoretical arrival time of the blade, in seconds; The time it takes for the impeller to rotate once, in seconds; is the blade vibration displacement, in mm; Indicates the current circle number, subscript is the leaf number, subscript The speed synchronization sensor number.

[0061] Furthermore, the tip amplitude curve of each blade 30 can be measured by each blade tip timing sensor 12 during continuous testing during the entire speed push-up or pull-down process;

[0062] 5. For the measured blade tip amplitude curve, single degree of freedom fitting and circumferential Fourier transform can be used to obtain vibration parameters such as vibration frequency, vibration amplitude, resonant speed, phase, excitation order, modal order, modal damping, etc. of each blade 30;

[0063] 6. Perform calculations or calibration tests (as appropriate) on the vibration stress distribution and the relationship between the tip amplitude and the vibration stress for each blade 30 under the excitation order of interest. This can yield a calibration relationship between the tip amplitude and the vibration stress for each blade 30 under each excitation order. Combined with the above tip amplitude calculations, the vibration stress at the maximum stress point of each blade 30 under each excitation order can be derived.

[0064] The non-contact vibration measurement of rotating blades in the present invention is based on the principle of blade tip timing. A speed synchronization sensor 9 is mounted near the end edge of the rotating blade disk 3, while a blade tip timing sensor 12 is mounted radially relative to the rotating blade disk 3 on the relatively stationary axial flow casing 11. The speed synchronization sensor 9 generates a zero-time reference pulse for each rotor rotation. Each time a blade 30 passes the blade tip timing sensor 12, the blade tip timing sensor generates a blade arrival pulse. The blade tip timing system records the arrival time of each blade based on the two pulse signals. Assuming the blades rotate at a constant speed, when the blades are not vibrating, the arrival time of the blades at the tip timing sensor 12 is the same for each rotation. When vibration occurs, the arrival time of the blades varies (the time taken to reach the same blade tip timing sensor 12 varies), resulting in a time difference. The vibration displacement of the blades can be calculated based on the arrival time difference between the vibrating and non-vibrating blades and related known parameters.

[0065] It should be noted that the above-described non-contact vibration measurement method and device for rotating blades of an entire engine is merely an example illustrating the specific design and implementation of the present invention, and is not limited to the specific structures of the rotating blade disk 3, the intake casing 1, the axial flow casing 11, etc. Those skilled in the art will appreciate that various modifications and variations are possible with the present invention (e.g., the blade profile, structural dimensions, and number of blades 30 of the rotating blade disk 3, the structural form of the intake casing 1 and the axial flow casing 11, the type of speed synchronization sensor 9, the circumferential position of the grooves 31, the number and circumferential mounting position of the blade tip timing sensor 12, etc.). Furthermore, the speed synchronization sensor 9 may be a magnetoelectric speed sensor or a photoelectric speed sensor. The blade tip timing sensor 12 may also employ a fiber optic sensor, an eddy current sensor, a capacitive sensor, etc. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

[0066] From the above description of the design device of the present invention, it can be seen that the present invention has at least the following advantages:

[0067] 1) The present invention can realize vibration measurement of rotating blades in the overall environment of the engine. Based on the blade tip timing principle, the blade tip amplitude signal is obtained, and the vibration characteristic parameters such as the vibration amplitude, resonant speed, vibration frequency, modal order, excitation order, and modal damping of the entire rotating blade are further obtained, providing a basis for vibration evaluation, life assessment, fault diagnosis, and improved design of the entire engine blade.

[0068] 2) The present invention solves the problem of no space for arranging a speed sensor in an engine-wide environment because the gas generator rotor is wrapped by the casing and blocked by other components such as the blades of the blisk. It provides a key phase signal with a 0-5V standard TTL level and a pulse falling edge width of only 0.5 microseconds for each revolution of the gas generator rotor, which provides the prerequisite for vibration measurement and data analysis of the rotating blades of the whole engine in engineering.

[0069] 3) The circumferential position layout of the blade tip timing sensors of the present invention is determined by sensor position optimization layout software. The optimized circumferential position of the blade tip timing sensors can satisfy the requirement of having at least four different response angles for each order of interest, thereby ensuring that a good vibration response can be measured at all engine orders of interest.

[0070] 4) The present invention optimizes the positional layout of the blade tip timing sensor and enables quick and reliable installation and removal, even when the external piping and other accessories of the engine casing are complexly distributed. This ensures the signal stability, reliability, and high signal-to-noise ratio of the non-contact vibration measurement of the rotating blades of the entire engine. It also ensures the vibration measurement safety of the blade tip timing sensor and the operational safety of the blades. When installing the blade tip timing sensor, the blade tip timing sensor 12 is fixed by tightening the fixing nut 14 to squeeze the elastic gasket 13 and deform it. When removing the blade tip timing sensor 12, the blade tip timing sensor is installed and removed by loosening the fixing nut 14 to restore the elastic gasket 13 to its original state and disengaging the blade tip timing sensor. This structural design is simple, effective, reliable, and efficient, significantly enhancing the effectiveness of the installation and removal of the blade tip timing sensor in non-contact vibration measurement of the rotating blades of the entire engine.

[0071] This invention has been applied and verified in the non-contact vibration measurement of rotating blades on a certain type of complete engine. Verification results demonstrate that this method and device for non-contact vibration measurement of rotating blades on a complete engine can effectively measure the tip amplitude of rotating blades under complete engine conditions, obtaining vibration characteristic parameters of the rotating blades. The tip timing sensor is easy to disassemble and install, and installation is reliable. The vibration measurement signal is stable and has a high signal-to-noise ratio. Verification tests revealed a first-order bending resonance of the blades caused by a third harmonic within the rated engine operating speed range. The maximum blade amplitude was 0.79 mm, corresponding to a vibration stress of 472 MPa.

[0072] In summary, the non-contact vibration measurement device for the rotating blades of an entire engine of the present invention is constructed by disposing a speed synchronization sensor axially penetrating the intake casing and the guide vane support, with the monitoring probe of the speed synchronization sensor disposed facing the rotating blade disk; providing a groove on the end face of the rotating blade disk at a position corresponding to the monitoring probe of the speed synchronization sensor; and disposing a plurality of blade tip timing sensors at circumferential positions on the axial flow casing corresponding to the radial direction of the rotating blade disk. The present invention measures the moment when the rotating blades of the entire engine reach the blade tip timing sensor based on the blade tip timing principle, converts the measured time pulse signal into a blade tip amplitude signal, and further extracts the vibration parameters of the rotating blades of the entire engine through a blade tip timing signal parameter identification method, thereby providing a basis for vibration evaluation, life assessment, fault diagnosis, and improved design of the entire rotating blades of the engine. The present invention realizes the effective measurement of the speed synchronization signal and the non-contact vibration measurement of the rotating blades in the environment of the entire engine, and at the same time ensures the reliable selection, reasonable installation and rapid assembly and disassembly of the layout position of the blade tip timing sensor in the environment of the entire engine, and ensures that the collected non-contact vibration measurement signal of the rotating blade has a good signal-to-noise ratio, thereby providing a simple, convenient and effective online monitoring means for the accurate identification of the engine order vibration mode of concern.

[0073] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A non-contact vibration measuring device for rotating blades of an entire engine, comprising: A rotating blade disk (3) disposed in an axial flow casing (11), a guide vane support (2) in contact with the rotating blade disk (3) via grate teeth, and an intake casing (1) integrally fixed to the guide vane support (2); characterized in that: A speed synchronization sensor (9) is provided axially through the air intake casing (1) and the guide vane support (2), and a monitoring probe of the speed synchronization sensor (9) is provided in a direction facing the rotating blade disk (3); A groove (31) is provided on the end face edge of the rotating blade disk (3) at a position corresponding to the monitoring probe of the speed synchronization sensor (9); A plurality of blade tip timing sensors (12) are arranged on the axial flow casing (11) at circumferential positions corresponding in radial direction to the rotating blade disk (3); The installation angle of the blade tip timing sensor (12) when arranged circumferentially on the axial flow casing (11) is based on ensuring that each blade tip timing sensor (12) can measure a good vibration response under the excitation of the first 10 rotor steps and the airflow excitation caused by the front and rear stator blades and support plates of the blade being measured, and is determined by calculation by the sensor position optimization layout software; The blade tip timing sensor (12) is fixed to the axial flow casing (11) via a sensor mounting seat (110); The sensor mounting seat (110) is provided with a stepped through hole for mounting the blade tip timing sensor (12), and the outer side of the sensor mounting seat (110) is provided with a thread. The blade tip timing sensor (12) passes through the fixing nut (14) and the elastic gasket (13) in sequence and is then inserted into the stepped through hole of the sensor mounting seat (110). By screwing the fixing nut (14) together, both sides of the elastic gasket (13) will contact the outer end surface of the sensor mounting seat (110) and the inner end surface of the fixing nut (14) respectively; A plurality of long bolts (10) for fixing a squirrel cage spring support (5) are provided in the air intake casing (1), and the squirrel cage spring support (5) supports and fixes a gas generator rotor with a rotating blade disk (3) on the air intake casing (1); The rotational speed synchronization sensor (9) is installed and fixed by replacing one of the long bolts (10); A through hole is provided at a position of the guide vane support (2) corresponding to the position where the speed synchronization sensor (9) is installed; The front end outer peripheral surface of the speed synchronization sensor (9) is provided with a thread, and the speed synchronization sensor (9) sequentially passes through the mounting hole of the squirrel cage spring support (5), the through hole of the air intake casing (1), and is threadedly connected to the guide vane support (2).

2. The non-contact vibration measuring device for rotating blades of an entire engine according to claim 1, characterized in that: The number of blade tip timing sensors (12) arranged at circumferential positions of the axial flow casing (11) is 4 to 8.

3. The non-contact vibration measuring device for rotating blades of an entire engine according to claim 1, characterized in that: The speed synchronization sensor (9) includes a magnetoelectric speed sensor or a photoelectric speed sensor.

4. The non-contact vibration measuring device for rotating blades of an entire engine according to claim 1, characterized in that: The blade tip timing sensor (12) comprises an optical fiber sensor, an eddy current sensor or a capacitive sensor.

5. A non-contact vibration measurement method for rotating blades of an entire engine, characterized in that: The vibration measurement method is performed on the non-contact vibration measurement device for rotating blades of an entire engine according to any one of claims 1 to 4, wherein the vibration measurement method comprises: The time T required for the rotating blade disk (3) to rotate one circle is determined by measuring the interval between two adjacent key phase pulses through the speed synchronization sensor (9). n , and the speed of the gas generator rotor; Determining the order in which the blades (30) successively pass through the blade tip timing sensor (12) based on the relative positions of the blades (30) on the rotating blade disk (3) and the speed synchronization sensor (9), thereby determining the number b of each blade (30); According to the rotation speed of the gas generator rotor and the determined number b of each blade (30), the theoretical arrival time t of each blade (30) passing the blade tip timing sensor (12) when the blade (30) is not vibrating is determined based on the key phase pulse of the rotation speed synchronization sensor (9). nbs0 and the actual arrival time t of each blade (30) passing the blade tip timing sensor (12) when vibrating nbs ; According to the theoretical arrival time t nbs0 , the actual arrival time t nbs The time T for the rotating blade disk (3) to rotate one circle n The vibration displacement of each blade (30) is determined by combining the distance from the blade tip to the center of the rotating blade disk (3).

6. The non-contact vibration measurement method for rotating blades of an entire engine according to claim 5, characterized in that: According to the theoretical arrival time t nbs0 , the actual arrival time t nbs The time T for the rotating blade disk to rotate one circle n , combined with the distance from the blade tip to the disk center of the rotating blade disk, the calculation formula for determining the vibration displacement of each blade is as follows: ； Where, The distance from the tip of the blade to the center of the rotating blade disk; is the actual arrival time of the blade; is the theoretical arrival time of the blade; The time it takes for the impeller to make one rotation; is the blade vibration displacement; Indicates the current lap number; subscript is the leaf number; subscript The number of the blade tip timing sensor.

7. The non-contact vibration measurement method for rotating blades of an entire engine according to claim 5 or 6, characterized in that: The method further comprises: The vibration measurement method is continuously tested by each blade tip timing sensor (12) during the entire rotation speed push-up or pull-down process to obtain a blade tip amplitude curve of each blade (30).

8. The non-contact vibration measurement method for rotating blades of an entire engine according to claim 7, characterized in that: The method further comprises: According to the blade tip amplitude curve, vibration parameters of each blade (30) are obtained through single degree of freedom fitting and circumferential Fourier transform; the vibration parameters include: vibration frequency, vibration amplitude, resonant speed, phase, excitation order, modal order and modal damping.

9. The non-contact vibration measurement method for rotating blades of an entire engine according to claim 5, characterized in that: The method further comprises: The vibration stress distribution and the relationship between the blade tip amplitude and the vibration stress of each blade (30) under the excitation order of interest are calculated or calibrated to obtain the calibration relationship between the blade tip amplitude and the vibration stress of each blade (30) under each excitation order, and the vibration stress of the maximum stress point of each blade (30) under each excitation order is calculated in combination with the vibration displacement of each blade (30).

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