Blade tip timing high-order vibration identification method and system based on blade tip acceleration

Abstract

Disclosed are a method and system for identifying blade tip timing high-order vibration based on blade tip acceleration. The method comprises: determining the number and angle of circumferential installation of a rotor blade casing by optimizing the position of sensors based on the need for identifying high-frequency vibration parameters of blades; conducting test measurements to obtain the actual arrival time sequence of rotor blades passing through the sensors; grouping three sensors together, converting blade tip timing analysis from blade tip vibration displacement to blade tip vibration acceleration using the arrival time and the installation angle of the sensors, and determining the blade vibration resonance area using a classic SDOF algorithm; establishing a compressed sensing model of undersampled blade tip vibration acceleration signals, determining the positions of non-zero elements of a vibration sparse coefficient vector after solving it using a sparse algorithm, determining the design matrix of a vibration equation corresponding to the rotor blade high-order vibration frequency and blade high-order vibration acceleration without prior information, and determining the amplitude and phase of the blade high-order vibration using a circumferential Fourier algorithm.

Description

Technical Field

[0001] The present invention relates to the technical field of non-contact measurement of rotor blades of rotating machinery, and in particular to a blade tip acceleration-based blade tip timing high-order vibration identification method and system. Background Art

[0002] High-order vibration of blades has an important impact on the performance and reliability of rotating mechanical equipment. High-order vibration of blades will increase the stress and fatigue damage of blades, thereby reducing the life of equipment, and will also generate noise and vibration, affecting the stability and working efficiency of equipment. Traditional blade tip timing technology generally calculates the vibration displacement of the blade tip based on the difference between theoretical and actual arrival times, and analyzes the vibration displacement data to obtain blade vibration parameters, such as amplitude, frequency, phase and other parameters. However, the traditional vibration displacement blade tip timing analysis technology will give the greatest weight to the low-frequency component, so only the low-order one-bend vibration parameters of the blade can be accurately obtained. For the identification of high-order vibration parameters, due to the low proportion of vibration energy, it is easily interfered by noise, so it currently faces great challenges. The present invention proposes a blade tip timing analysis technology based on blade tip acceleration, which converts the measured physical quantity from blade tip vibration displacement to the measurement of blade tip vibration acceleration, and uses acceleration measurement to weight the high-frequency component, so as to further improve the accuracy of blade high-order vibration parameter identification. In addition, high-order vibration may be related to faults such as blade angle drop, and the blade tip acceleration blade tip timing analysis technology proposed in the present invention is crucial to the safe operation of the engine.

[0003] The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a full-frequency domain blade tip timing vibration parameter identification method and system to solve the problem of potential high-order measurement inaccuracy in the existing blade tip timing software system calibration. By using acceleration measurement to weight the high-frequency components, it is possible to convert the blade tip vibration displacement into the blade tip vibration acceleration measurement, thereby realizing the identification of high-order vibration parameters of the blade.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A blade tip timing high-order vibration identification method based on blade tip acceleration of the present invention comprises:

[0007] The first step S100 is to determine the number and angle of blade tip timing sensors installed in the circumferential direction of the rotor blade casing based on high-frequency vibration parameters with a vibration frequency of 2000 Hz-5000 Hz. The high-order vibration parameters of the rotor blades include the vibration frequency f H , Amplitude AmH and phase φ H , where at least three blade tip timing sensors are arranged to obtain a set of blade tip vibration acceleration signals, so the number of circumferential installations of the rotor casing is N p Should satisfy N p ≥3;

[0008] In the second step S200, a blade tip timing sensor is circumferentially mounted on a rotor blade casing to obtain a time series of the rotor blade reaching the blade tip timing sensor;

[0009] The third step S300 is to obtain the blade tip vibration acceleration according to the installation angles of three adjacent blade tip timing sensors and the measured blade arrival time, and determine the blade vibration resonance area by using a classic SDOF algorithm;

[0010] The fourth step S400 is to establish a sparse representation model of the undersampled blade tip vibration acceleration based on the blade tip vibration acceleration, determine the blade vibration frequency after solving it using a sparse algorithm, and at the same time, construct a design matrix based on the positioning of non-zero elements of the sparse solution, and use a circumferential Fourier algorithm to determine the amplitude and phase of the blade's high-order vibration.

[0011] In the method described, in the first step S100, the installation angles of three adjacent blade tip timing sensors are spaced no more than 10° apart from each other.

[0012] In the method described above, in the second step S200, the arrival time series matrix of the rotor blade passing through the blade tip timing sensor is collected. Size is N b *N×N p , where t i,j,n It indicates the arrival time of blade No. j measured by blade tip timing sensor No. i at the nth rotation. The rotor blades contain N b Blades, circumferentially mounted N p A blade tip timing sensor is used to continuously collect N rounds of data.

[0013] In the method described, the third step S300 estimates the rotor angular acceleration β according to the arrival time and the blade rotation angle fitting, takes the blade arrival time as the independent variable, and the blade rotation angle as the dependent variable, and considers the influence of speed fluctuation, and fits the blade arrival time measured by multiple sensors in each circle with the corresponding rotation angle using a quadratic polynomial function least squares to obtain: in, are the coefficients of the fitted quadratic polynomial function, P i,j,n It means that the blade tip timing sensor of No. i measures the rotation angle of No. j blade in the nth circle. Since the blade does not rotate at the beginning of the measurement, the measured blade rotation angle is zero.

[0014] The working speed is in a constant speed state, the speed does not change, that is, the angular acceleration β=0, and the speed is in a variable speed state. The quadratic function of the rotation angle and the arrival time fitting is quadratically derived to obtain the angular acceleration β=a of the rotor system.

[0015] In the method described above, in the third step S300, the arrival time t of the jth blade at the nth rotation is measured by three blade tip timing sensors i-1, i, i+1. i-1,j,n ,t i,j,n ,t i+1,j,n and installation angle θ i-1 ,θ i ,θ i+1 Calculate the acceleration of blade tip vibration in, R represents the measured rotation radius from the rotor blade tip rotation axis to the blade tip; the blade tip vibration acceleration signal is obtained by fitting using the classic SDOF algorithm, and the peak sudden increase is the area where the blade resonates.

[0016] In the method described above, in the fourth step S400,

[0017] The blade tip vibration acceleration is expressed as in, The vibration coefficient of the blade tip vibration acceleration is expressed as the frequency bandwidth [f Δ1 ,f Δ2 ,…,f ΔG ] and the arrival time of the blade tip acceleration Construct the measurement matrix of N-turn under-sampling blade tip timing blade tip acceleration:

[0018]

[0019] Among them, the vibration frequency of the rotor blades is H Included in the frequency bandwidth [f Δ1 ,f Δ2 ,…,f ΔG ], To calculate the average arrival time collected by the three blade tip timing sensors i-1, i, i+1 in the nth round, it is

[0020] In the method, in the fourth step S400, based on the measurement matrix Φ, a sparse representation model of the rotor blade tip vibration acceleration signal is constructed as follows: Where λ is the regularization parameter, A is the blade tip vibration acceleration measured based on the arrival time, θ is the unknown blade tip vibration acceleration coefficient vector, where, Using non-convex optimization method to solve the l 1 / 2The sparse representation model of the norm determines the corresponding blade vibration frequency f based on the position of the non-zero elements in the acceleration sparse solution vector H , the corresponding blade tip vibration acceleration design matrix H, using the circumferential Fourier algorithm Get the blade tip vibration acceleration vibration coefficient in, is the generalized inverse matrix of the design matrix.

[0021] In the method described, the blade vibration displacement amplitude is obtained based on the rotor blade vibration frequency. Vibration Phase

[0022] A system for implementing a blade tip acceleration-based blade tip timing high-order vibration identification method comprises:

[0023] a blade tip arrival time measurement module configured to collect an arrival time sequence of a rotor blade passing a blade tip timing sensor;

[0024] A rotor angular acceleration calculation module is connected to the blade tip arrival time measurement module, and the rotor angular acceleration calculation module determines the acceleration of the rotor blade according to the arrival time and the rotation angle quadratic function fitting measured by the blade tip timing;

[0025] a blade tip vibration acceleration calculation module, which is connected to the blade tip arrival time measurement module and the rotor angular acceleration calculation module, and the blade tip vibration acceleration calculation module calculates the blade tip vibration acceleration based on the arrival time and the installation angle interval of three adjacent sensors;

[0026] A high-order vibration parameter identification module is connected to the blade tip arrival time measurement module and the blade tip vibration acceleration calculation module. The high-order vibration parameter identification module establishes a sparse representation model of under-sampled blade tip vibration acceleration based on the blade tip vibration acceleration, determines the blade vibration frequency by sparse solution, and constructs a design matrix based on the positioning of non-zero elements of the sparse solution, and identifies the vibration amplitude and phase of the blade multi-mode through the least squares algorithm.

[0027] The system also includes a blade status monitoring module connected to the high-order vibration parameter identification module, which monitors the blades in real time and issues an early warning based on the vibration amplitude and phase.

[0028] Beneficial Effects

[0029] Unlike traditional methods that focus on identifying vibration parameters from blade tip vibration displacement measurements, this patent uses blade tip vibration acceleration for blade tip timing analysis. At the same time, this patent does not use OPR reference sensors or virtual reference sensors to calculate the ideal arrival time of the blade, reducing uncertainty in the measurement process. The high-frequency amplitude is enhanced according to the characteristics of weighting the high-frequency component based on acceleration measurement, thereby facilitating the identification of high-order vibration parameters of the rotor blades, which is of great significance to the application of non-contact measurement systems for rotor blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0031] By reading the detailed description of the preferred specific embodiments below, various other advantages and benefits of the present invention will become clear to those of ordinary skill in the art. The drawings in the specification are only for the purpose of illustrating the preferred embodiments and are not considered to be limitations of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative work. Moreover, the same reference numerals are used to represent the same components throughout the drawings.

[0032] In the attached picture:

[0033] Figure 1 A schematic flow chart of a method for identifying blade tip timing high-order vibration based on blade tip acceleration provided by an embodiment of the present invention;

[0034] Figure 2 A schematic diagram of the structure of a system for implementing the blade tip timing high-order vibration identification method based on blade tip acceleration provided in one embodiment of the present invention;

[0035] Figure 3 A schematic diagram of calculating blade tip vibration acceleration based on the installation angles of three adjacent blade tip timing sensors provided by an embodiment of the present invention;

[0036] Figure 4 A schematic diagram of the circumferential angle installation position of a blade tip timing sensor provided by an embodiment of the present invention;

[0037] Figure 5(a) to Figure 5(b) A schematic diagram of a measured blade vibration response provided by an embodiment of the present invention, FIG5(a) is a blade tip vibration acceleration; FIG5(b) is a measured blade dynamic strain used as a reference for vibration frequency identification;

[0038] Figure 6(a) to Figure 6(b) A schematic diagram of blade vibration frequency identification results is provided for an embodiment of the present invention, wherein FIG6(a) is a blade tip timing parameter identification result based on blade tip vibration acceleration response; FIG6(b) is a parameter table identification result based on actual blade dynamic strain as a reference.

[0039] The present invention is further explained below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are 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 creative work are within the scope of protection of the present invention.

[0041] Therefore, the following Figure 1 to Figure 6(b) The detailed description of the embodiments of the present invention provided in the present invention is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0042] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not require further definition and explanation in subsequent drawings.

[0043] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0044] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0045] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0047] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings. A blade tip timing high-order vibration identification method based on blade tip acceleration includes:

[0048] In the first step S100, based on the requirement of blade high-frequency vibration parameter identification, the number and angle of sensors installed circumferentially on the rotor blade casing are determined by optimizing the sensor positions;

[0049] In the second step S200, a test measurement is carried out to obtain an actual arrival time series of the rotor blades passing the sensor;

[0050] In the third step S300, the three sensors are taken as a group, and the blade tip timing analysis is converted from blade tip vibration displacement to blade tip vibration acceleration by using the arrival time and the installation angle of the sensor, and the blade vibration resonance area is determined by the classic SDOF algorithm;

[0051] In the fourth step S400, a compressed sensing model of the undersampled blade tip vibration acceleration signal is established, and the positions of non-zero elements of the vibration sparse coefficient vector are determined by solving the sparse algorithm. The design matrix of the vibration equation corresponding to the high-order vibration frequency of the rotor blade and the high-order vibration acceleration of the blade can be determined without prior information, and the amplitude and phase of the high-order vibration of the blade are determined by the circumferential Fourier algorithm.

[0052] In the blade tip timing high-order vibration measurement method based on blade tip vibration acceleration, in the first step S100, the rotor blade high-order vibration parameters include frequency (f H ), Amplitude (Am H ) and phase (φ H ), where a set of blade tip vibration acceleration signals need to be acquired using three blade tip timing sensors, so the number of rotor casing circumferential installations N p Should satisfy N p ≥3.

[0053] In the method described, in the first step S100, the three blade tip timing sensor angles can obtain a set of blade tip vibration accelerations. Under the condition of meeting the actual situation, the smaller the interval between the sensors, the higher the accuracy. It is recommended that the interval between the three adjacent sensor angles should not be greater than 10°.

[0054] In the first step S200 of the method, an experiment is carried out and a time series matrix of the arrival of the blade through the sensor is collected. Size is N b *N×N p , where t i,j,n It means the arrival time of blade No. j measured by blade tip timing sensor at the nth rotation of blade No. i. The rotor contains N b Blades, circumferentially mounted N p A blade tip timing sensor continuously collects N rounds of data;

[0055] In the method, in the first step S200, the rotor working acceleration β is estimated based on the arrival time and the blade rotation angle fitting, specifically taking the blade arrival time as the independent variable and the blade rotation angle as the dependent variable, and considering the influence of the speed fluctuation, the blade arrival time measured by multiple sensors in each circle and the corresponding rotation angle are fitted by the quadratic polynomial function least squares to obtain: in, are the coefficients of the fitted quadratic polynomial function, P i,j,n It means that the blade tip timing sensor of No. i measures the rotation angle of No. j blade in the nth circle. Since the blade does not rotate at the beginning of the measurement, the measured blade rotation angle is zero.

[0056] S201, if the operating speed is in a constant speed state, the speed does not change, that is, the angular acceleration β of the rotor system = 0;

[0057] S202, if the working speed is in a variable speed state, the angular acceleration β=a of the rotor system can be obtained by taking the second derivative of the quadratic function of the rotation angle and the arrival time fitting;

[0058] In the method, in the first step S300, the arrival time t of the jth blade at the nth rotation is measured by three blade tip timing sensors i-1, i, i+1. i-1,j,n ,t i,j,n ,t i+1,j,n and installation angle θ i-1 ,θ i ,θ i+1 The acceleration of blade tip vibration can be calculated in, The blade tip vibration acceleration signal is obtained by fitting using the classic SDOF algorithm. The peak value increase is the area where the blade resonates.

[0059] In the method described above, in the first step S400, the vibration of the blade can generally be assumed to be a harmonic signal of different frequencies. Based on the blade tip high-frequency vibration acceleration signal, it can be expressed as: in, Expressed as the blade tip high frequency vibration acceleration f H The vibration coefficient of the signal, the frequency bandwidth [f Δ1 ,f Δ2 ,…,f ΔG ] and the arrival time of the blade tip acceleration Construct the measurement matrix of N-turn under-sampling blade tip timing acceleration signal:

[0060]

[0061] Among them, the high-order frequency f of the rotor blade H Included in setting the frequency bandwidth [f Δ1 ,f Δ2 ,…,f ΔG ], The three blade tip timing sensors i-1, i, i+1 used to calculate the blade tip acceleration collect the average value of the arrival time collected in the nth circle, where:

[0062] In the method, in the first step S400, based on the measurement matrix Φ of the blade tip acceleration, the sparse representation model of the rotor blade tip vibration acceleration signal can be further expressed as Where λ is the regularization parameter, and A is the blade tip vibration acceleration measured based on the sensor and the acquired arrival time, that is, θ is the unknown blade tip vibration acceleration coefficient vector, where, Using non-convex optimization method to solve the above l-based 1 / 2 The sparse optimization model of the norm determines the corresponding blade high-order vibration frequency f based on the position of the non-zero elements in the acceleration sparse solution vector H, the corresponding blade tip vibration acceleration design matrix H, using the circumferential Fourier algorithm Obtain the high-order vibration coefficients of blade tip vibration acceleration in, is the generalized inverse matrix of the design matrix;

[0063] In the method, in the first step S400, according to the conversion relationship between the measured blade tip vibration displacement and acceleration, the blade high-order vibration displacement parameter, that is, the blade high-order vibration displacement amplitude, is finally obtained. High-order vibration phase

[0064] In order to further understand the present invention, the present invention is further described below through specific embodiments. It should be emphasized that the following description is merely illustrative and should not be regarded as a limitation of the present invention.

[0065] 1. Set the six sensor numbers to increase in clockwise order, then the optimal layout angles of each sensor are θ1 = 10°, θ2 = 25°, θ3 = 35°, θ4 = 45°, θ5 = 65°, θ6 = 75°. Figure 4 shown.

[0066] 2. Conduct an experiment to measure the arrival time of the blades. The arrival time of blade No. 1 passing through sensors No. 1, 2, and 3 is selected. The installation angle intervals are 5° and 10°. The blade tip vibration acceleration is calculated as shown in Figure 5(a). The blade tip vibration acceleration response has an obvious peak when the speed reaches 9600RPM, and the blade reaches resonance at this time. At the same time, as a control for accurate parameter identification, the dynamic strain of the blade on the right side of the root during the speed increase process is measured as shown in Figure 5(b). Similarly, when the speed reaches 9600RPM, the strain response has an obvious peak, so the blade reaches resonance in the speed range.

[0067] 3. Set the ideal non-undersampling frequency f s = 6000Hz, a sparse model of the blade tip timing acceleration non-undersampling signal is constructed, and the above l-based 1 / 2 The ideal non-undersampled vibration acceleration vector at the blade tip timing measurement point is obtained by sparse reconstruction of the norm, and the spectrum is obtained by fast Fourier transform as shown in Figure 6(a). In addition, the sampling frequency of dynamic strain measurement is 12800 Hz, and the spectrum of the resonance region response is also obtained by fast Fourier transform as shown in Figure 6(b).

[0068] Although the first two modal frequencies can be clearly obtained based on dynamic strain measurement, the third-order modal frequency is easily disturbed by noise because the proportion of high-order energy is smaller than that of low-order energy, resulting in inaccurate high-order identification of the third-order mode. However, by converting the physical quantity of blade tip timing analysis into blade tip acceleration, based on the high-order weighted characteristics of acceleration, high-order frequencies such as the third-order mode can be accurately identified.

[0069] According to another aspect of the present invention, the present disclosure also provides a blade tip timing high-order vibration parameter identification system of blade tip vibration acceleration, comprising:

[0070] Blade tip arrival time measurement module: Based on the circumferential layout of blade tip timing sensors, experiments are conducted to collect blade arrival time series;

[0071] Rotor angular acceleration calculation module: determines the acceleration of the rotor system by fitting a quadratic function based on the arrival time and rotation angle measured by the blade tip timing;

[0072] A blade tip vibration acceleration calculation module: calculates the blade tip vibration acceleration using the arrival time and the installation angle interval of three adjacent sensors, and converts the blade tip timing measurement physical quantity into the blade tip vibration acceleration;

[0073] High-order vibration parameter identification module: used to establish a sparse representation model of the undersampled blade tip vibration acceleration signal, determine the high-order vibration frequency of the blade by sparse solution, and construct a design matrix based on the positioning of non-zero elements of the sparse solution, and identify the vibration amplitude and phase of the blade multi-mode through the least squares algorithm.

[0074] Blade status monitoring module: real-time monitoring of abnormal conditions such as blade cracks, wear and surge, early warning of equipment failures, reducing equipment maintenance costs, and improving engine reliability and safety.

[0075] The disclosed blade tip timing high-order vibration measurement does not require prior information or the installation of a speed reference sensor. It measures the blade tip vibration acceleration instead of the traditional blade tip vibration displacement to achieve accurate identification of blade high-order vibration, further expanding the engineering application of blade tip timing technology.

[0076] Finally, it should be noted that the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making any creative work are within the scope of protection of the present application.

[0077] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A blade tip timing high-order vibration identification method based on blade tip acceleration, characterized in that: It includes the following steps: The first step S100 is to determine the number and angle of blade tip timing sensors installed in the circumferential direction of the rotor blade casing based on high-frequency vibration parameters with a vibration frequency of 2000 Hz-5000 Hz. The high-order vibration parameters of the rotor blades include the vibration frequency f H , Amplitude Am H and phase φ H , where at least three blade tip timing sensors are arranged to obtain a set of blade tip vibration acceleration signals, so the number of circumferential installations of the rotor casing is N p Should satisfy N p ≥3; In the second step S200, a blade tip timing sensor is circumferentially mounted on a rotor blade casing to obtain a time series of the rotor blade reaching the blade tip timing sensor; The third step S300 is to obtain the blade tip vibration acceleration according to the installation angles of three adjacent blade tip timing sensors and the measured blade arrival time, and determine the blade vibration resonance area by using a classic SDOF algorithm; The fourth step S400 is to establish a sparse representation model of the undersampled blade tip vibration acceleration based on the blade tip vibration acceleration, determine the blade vibration frequency after solving it using a sparse algorithm, and at the same time, construct a design matrix based on the positioning of non-zero elements of the sparse solution, and use a circumferential Fourier algorithm to determine the amplitude and phase of the blade's high-order vibration.

2. The method according to claim 1, characterized in that: Preferably, in the first step S100, the installation angles of three adjacent blade tip timing sensors are spaced apart by no more than 10°.

3. The method according to claim 2, characterized in that In the second step S200, the arrival time series matrix of the rotor blade passing the blade tip timing sensor is collected. Size is N b *N×N p , where t i,j,n It indicates the arrival time of blade No. j measured by blade tip timing sensor No. i at the nth rotation. The rotor blades contain N b Blades, circumferentially mounted N p A blade tip timing sensor is used to continuously collect N rounds of data.

4. The method according to claim 1, characterized in that: In the third step S300, the angular acceleration β of the rotor is estimated according to the arrival time and the rotation angle of the blade. The blade arrival time is used as the independent variable and the blade rotation angle is used as the dependent variable. The influence of the speed fluctuation is considered at the same time. The blade arrival time measured by multiple sensors in each circle and the corresponding rotation angle are fitted by the quadratic polynomial function least squares to obtain: in, are the coefficients of the fitted quadratic polynomial function, P i,j,n It means that the blade tip timing sensor of No. i measures the rotation angle of No. j blade in the nth circle. Since the blade does not rotate at the beginning of the measurement, the measured blade rotation angle is zero. The working speed is in a constant speed state, the speed does not change, that is, the angular acceleration β=0, and the speed is in a variable speed state. The quadratic function of the rotation angle and the arrival time fitting is quadratically derived to obtain the angular acceleration β=a of the rotor system.

5. The method according to claim 4, characterized in that In the third step S300, the arrival time t of the jth blade at the nth rotation is measured by the three blade tip timing sensors i-1, i, i+1. i-1,j,n ,t i,j,n ,t i+1,j,n and installation angle θ i-1 ,θ i ,θ i+1 Calculate the acceleration of blade tip vibration in, R represents the measured rotation radius from the rotor blade tip rotation axis to the blade tip. The blade tip vibration acceleration signal is obtained by fitting using the classic SDOF algorithm. The peak value surge is the area where the blade resonates.

6. The method according to claim 5, characterized in that In the fourth step S400, The blade tip vibration acceleration is expressed as in, The vibration coefficient of the blade tip vibration acceleration is expressed as the frequency bandwidth [f Δ1 ,f Δ2 ,…,f ΔG ] and the arrival time of the blade tip acceleration Construct the measurement matrix of N-turn under-sampling blade tip timing blade tip acceleration: Among them, the vibration frequency of the rotor blades is H Included in the frequency bandwidth [f Δ1 ,f Δ2 ,…,f ΔG ], To calculate the average arrival time collected by the three blade tip timing sensors i-1, i, i+1 in the nth round, it is 7. The method according to claim 6, characterized in that In the fourth step S400, based on the measurement matrix Φ, a sparse representation model of the rotor blade tip vibration acceleration signal is constructed as follows: Where λ is the regularization parameter, A is the blade tip vibration acceleration measured based on the arrival time, θ is the unknown blade tip vibration acceleration coefficient vector, where, Using non-convex optimization method to solve the l 1 / 2 The sparse representation model of the norm determines the corresponding blade vibration frequency f based on the position of the non-zero elements in the acceleration sparse solution vector H , the corresponding blade tip vibration acceleration design matrix H, using the circumferential Fourier algorithm Get the blade tip vibration acceleration vibration coefficient in, is the generalized inverse matrix of the design matrix.

8. The method according to claim 7, characterized in that Obtain blade vibration displacement amplitude based on rotor blade vibration frequency Vibration Phase 9. A system for implementing the blade tip timing high-order vibration identification method based on blade tip acceleration as described in any one of claims 1 to 8, characterized in that: These include, a blade tip arrival time measurement module configured to collect an arrival time sequence of a rotor blade passing a blade tip timing sensor; A rotor angular acceleration calculation module is connected to the blade tip arrival time measurement module, and the rotor angular acceleration calculation module determines the acceleration of the rotor blade according to the arrival time and the rotation angle quadratic function fitting measured by the blade tip timing; a blade tip vibration acceleration calculation module, which is connected to the blade tip arrival time measurement module and the rotor angular acceleration calculation module, and the blade tip vibration acceleration calculation module calculates the blade tip vibration acceleration based on the arrival time and the installation angle interval of three adjacent sensors; A high-order vibration parameter identification module is connected to the blade tip arrival time measurement module and the blade tip vibration acceleration calculation module. The high-order vibration parameter identification module establishes a sparse representation model of under-sampled blade tip vibration acceleration based on the blade tip vibration acceleration, determines the blade vibration frequency by sparse solution, and constructs a design matrix based on the positioning of non-zero elements of the sparse solution, and identifies the vibration amplitude and phase of the blade multi-mode through the least squares algorithm.

10. The system according to claim 9, characterized in that It also includes a blade status monitoring module connected to the high-order vibration parameter identification module, which monitors the blades in real time and issues an early warning based on the vibration amplitude and phase.

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