Blade tip timing asynchronous vibration parameter identification method and system for blade tip vibration acceleration

Abstract

Disclosed are a blade tip timing asynchronous vibration parameter identification method and system based on blade tip vibration acceleration, at least one set of three blade tip timing sensors is installed equiangularly and circumferentially on an engine casing; time series of each rotating rotor blade reaching the blade tip timing sensor is obtained under variable speed conditions; under different conditions of variable speed or constant speed, the arrival time of each rotor blade measured in each rotation is taken as the dependent variable, and the arrival angle of each rotor blade is taken as the independent variable to perform linear fitting to reproduce the speed information of each rotation; an asynchronous vibration parameter identification model based on blade tip vibration acceleration is established; based on the asynchronous vibration parameter identification model, the full blade spectrum method is used to identify the asynchronous vibration frequency and amplitude; based on the asynchronous vibration parameter identification model, the MUSIC method is used to identify the asynchronous vibration frequency of the rotor blade first, and then the blade vibration amplitude is obtained through the identification result.

Description

Technical Field

[0001] This invention relates to the field of non-contact measurement technology for rotating blades of rotating machinery, and in particular to a method and system for identifying blade tip timed asynchronous vibration parameters based on blade tip vibration acceleration. Background Technology

[0002] Traditional blade tip timing technology uses blade tip timing sensors mounted on a fixed casing to measure the arrival time of rotating blades. A reference sensor mounted near the rotating shaft provides rotational speed information and a time reference. By calculating the difference between the two time values, the blade's vibration displacement can be determined, thus obtaining characteristic parameters of the blade vibration, such as amplitude, frequency, and stress, thereby obtaining the engine's operating status. Asynchronous vibration blades exhibit vibration frequencies that are not integer multiples of the rotational speed, resulting from unsteady flow transferring some of its energy to the blades. Common asynchronous vibration faults include flutter, surge, and rotational stall. These faults are mainly related to airflow disturbances during the operation of rotating machinery, posing significant risks to the safe operation of engine rotating blades. Identifying asynchronous vibration parameters faces the challenge of large rotational speed variations. Furthermore, the reference sensor is mounted at a certain distance from the rotating blade, and the complex internal environment of the engine makes the reference sensor measurements susceptible to interference, leading to measurement errors. The harsh internal environment of the engine can also cause sensor failure or even detachment. Therefore, this invention, by calculating the blade tip vibration acceleration using the measured arrival time and installation angle based on the relationship between blade tip vibration displacement and acceleration, achieves accurate identification of blade vibration parameters without the need to calculate any reference rotational speed and prior information, further expanding the engineering application of blade tip timing measurement technology in asynchronous vibration parameter identification problems.

[0003] The information disclosed in the background section is only intended to enhance the understanding of the background of the present invention, and therefore may contain information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a method and system for identifying asynchronous vibration parameters at the blade tip based on blade tip vibration acceleration. When aero-engine rotating blades experience asynchronous vibrations such as rotating stall, surge, and acoustic resonance, in the absence of a speed reference sensor or with variable speed, it eliminates the need to calculate a reference speed. Instead, it uses the relationship between the arrival time and installation angle measured at the blade tip to calculate the blade tip vibration acceleration, replacing the traditional blade tip vibration displacement. This eliminates the uncertainty in speed calculation during the measurement process, thereby improving the accuracy of asynchronous vibration parameter identification.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] The present invention provides a method for identifying timed asynchronous vibration parameters at the blade tip based on blade tip vibration acceleration, comprising:

[0007] In the first step S1, at least one set of three blade tip timing sensors is circumferentially mounted on the engine casing at equal angles.

[0008] The second step, S2, is to acquire the time sequence of each rotating rotor blade reaching the blade tip timing sensor under variable speed conditions.

[0009] In the third step S3, under different operating conditions of variable speed or constant speed, the arrival time of each rotor blade measured in each revolution is used as the dependent variable and the arrival angle of each rotor blade is used as the independent variable to perform linear fitting in order to reproduce the speed information of each revolution.

[0010] The fourth step, S4, calculates the blade tip vibration acceleration based on the time series and installation angle of a set of three adjacent blade tip timing sensors.

[0011] Step S5: Establish an asynchronous vibration parameter identification model based on blade tip vibration acceleration;

[0012] Step S6: Based on the asynchronous vibration parameter identification model, the full blade spectrum method is used to identify the asynchronous vibration frequency and amplitude.

[0013] In the seventh step S7, based on the asynchronous vibration parameter identification model, the asynchronous vibration frequency of the rotor blades is first identified using the MUSIC method, and then the vibration amplitude of the blades is obtained through the identification results.

[0014] In the method described, three leaf-end timing sensors in a group are circumferentially installed at equal angles and the interval between each pair is less than 10°.

[0015] In the method described, in the second step S2, an experiment is conducted under variable speed conditions to obtain the time series matrix of each rotating rotor blade reaching the blade tip timing sensor. Size N b *N×N p Among them, t i，j，n This represents the arrival time measured by the timing sensor at the i-th blade tip during the n-th rotation of the j-th blade. The rotor contains a total of N... b One blade, circumferentially mounted with N p A timing sensor at the leaf tip continuously collects data from N revolutions.

[0016] In the method described, in the third step S3, the relationship between the blade arrival time and the rotation angle position is as follows: Among them, P i，j，n This indicates that the timing sensor at the i-th blade tip measures the angle of rotation of the j-th blade in the n-th revolution. The total number of rotor blades is N. bOne blade, based on multimodal measurement, installed N p A leaf tip timing sensor, PA i Let BA be the installation angle of the i-th leaf tip timing sensor. j This represents the actual j-th installation interval.

[0017] In the method described, in the third step S3, the rotational speed within the circle changes linearly, and the blade rotational speed is... The blade arrival time measured by multiple blade tip timing sensors in each revolution is fitted with the corresponding rotation angle using a quadratic function least squares fit to obtain: in, The coefficients of the fitted quadratic function are obtained; after solving, the rotation period T of each revolution is obtained. i，j，n The blade rotation speed is calculated.

[0018] In the method described above, in the fourth step S4, three consecutively adjacent circumferential leaf tip timing sensors (i, i+1, and i+2, i = 1, 2, ..., N) are used. p -2, collect the actual arrival time t of the g-th blade in the nth orbit. i，g，n , t j，g，n , t k，g，n The blade tip vibration velocity between the two adjacent blade tip timing sensors is calculated. Calculate the i-th vibration acceleration value of the blade tip within the nth revolution based on the blade tip vibration velocity. in Represented as: Where R is the radius of rotation of the blade tip, f Ω Let θ be the blade rotational speed frequency. i Let t be the installation angle of the i-th sensor. i，g，n This represents the arrival time of the g-th blade, collected by the i-th sensor in the n-th cycle.

[0019] In the method described, in step S5, an asynchronous vibration parameter identification model is established, i.e., the blade vibration equation is: In the formula: M is the mass matrix, c is the damping matrix, K is the stiffness matrix, and ω1 is the fundamental frequency of the asynchronous vibration excitation force ω1=2πEo1f r Incentive level EO n =nEO1, the solution to the vibration equation is

[0020] In the method described, in the sixth step S6, the asynchronous vibration frequency and amplitude are identified using the full blade spectrum method, and the amplitude S of the blade response is determined. k and phase φ k Represented as: Where: N bThe total number of blades on the bladed disk; ND is the nodal diameter related to the bladed disk vibration, with positive ND for positive traveling waves and negative ND for negative traveling waves; A ND and ψ ND The response amplitude and phase are given when the blade disk pitch diameter is ND; ND max For an even number of blades, the equation ND is satisfied. max =N b / 2, for odd-numbered blades, the equation ND is satisfied. max =(N b -1) / 2;ND min For an even number of blades, the equation ND is satisfied. min =1-N b / 2, for odd-numbered blades, the equation ND is satisfied. max =-(N) b -1) / 2, for a single excitation frequency in a rotating reference frame, the above equation can be corrected to obtain the blade response as: In the formula, fr represents the rotational frequency of the bladed disk. Assuming all blades vibrate at the same frequency, a spatial Fourier transform of the vibration displacement of continuous blades yields the traveling wave response in the measurement reference frame, where the traveling wave frequency is f. tw Satisfy f tw =f b +NDf r f b This represents the vibration frequency of the blade. This is the whole-blade spectrum analysis method.

[0021] In the method described, in the seventh step S7, multiple segments of blade tip timing acceleration data of the same length are extracted as snapshots. The vector representation of the q-th snapshot is: a(q)=[a(t J(q-1)+1 ) a(t J(q-1)+2 ) … a(t J(q-1)+M ]], J is the number of leaf-end sensors in the circumferential layout; M is the length of the snapshot vector, satisfying mod(M, J)=0, and the snapshot matrix is ​​constructed as A=[a(1)a(2) … a(Q)]; the autocorrelation matrix is ​​calculated based on the snapshot matrix. When the leaf-end timing data is acceleration, the autocorrelation matrix is Eigenvalue decomposition is performed on the autocorrelation matrix, and the eigenvalues ​​are sorted from largest to smallest. The eigenvectors corresponding to the first L eigenvalues ​​form the signal subspace s, and the eigenvectors corresponding to the remaining ML eigenvalues ​​form the noise subspace G, satisfying: S T When G = 0, by setting a threshold p, according to the formula... Determine the number of frequency components L of the real signal, set the frequency traversal interval and step size, perform frequency traversal, and the steering vector expression for a given frequency f is: Where τ m For the m-th time value in each snapshot, the pseudospectral amplitude expression corresponding to a given frequency is as follows:

[0022] In the method described above, in step S7, in order to identify the asynchronous vibration amplitude of the blade using the MUSIC method, it is necessary to analyze the autocovariance matrix of the timing signal at the blade tip, and represent the snapshot vector as: BΛ f a+w(q), where B=[b1(q) b2(q) … b K (q)], where

[0023] w(q) = [w(t)] q1 ) w(t q2 … w(t) qM )] T Therefore, the sample autocorrelation matrix can be expressed as In the formula Λ a A diagonal matrix consisting of the squares of the amplitudes of each order satisfies... Let I be the variance of w(t); M Let Λ be an M-order identity matrix. In the sample covariance matrix, Λ a It contains information on the amplitude of blade vibration. Obtain the blade vibration amplitude

[0024] A system for implementing the blade tip timing asynchronous vibration parameter identification method based on blade tip vibration acceleration includes,

[0025] The sensor layout optimization module is configured to determine the number of circumferentially mounted blade tip timing sensors and the installation angle and position layout of each blade tip timing sensor.

[0026] The blade arrival time measurement module measures the arrival time sequence of each blade through timing sensors at each blade tip under variable speed conditions.

[0027] The blade tip vibration acceleration calculation module is connected to the blade arrival time measurement module. The 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.

[0028] The blade asynchronous vibration parameter identification module is connected to the blade tip vibration acceleration calculation module. The blade asynchronous vibration parameter identification module identifies the asynchronous vibration frequency of the rotor blade using the whole blade spectrum analysis method or the MUSIC method. Using the identification results, the vibration amplitude under the blade rotation stall and surge conditions is obtained through the amplitude extraction multi-signal classification method.

[0029] Beneficial effects

[0030] This invention addresses the issue of asynchronous vibrations in aero-engine blades, such as rotating stall, surge, and acoustic resonance, without the need for traditional reference speed sensors. It utilizes arrival time sequences and arrival angle relationships measured by various sensors under constant or variable speed conditions to obtain a reference speed signal through fitting. Furthermore, it calculates the blade tip vibration acceleration by analyzing the arrival time and installation angle relationship of the blade tip timing sensor, replacing the traditional blade tip vibration displacement physical quantity. This shifts the blade vibration displacement domain to the acceleration domain for analysis, improving the accuracy of high-frequency blade vibration identification. Compared to traditional blade tip vibration displacement calculation, it omits the reference speed calculation process, further reducing uncertainties in the blade tip timing measurement process and enhancing the accuracy of identifying asynchronous blade vibration parameters. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0032] Various other advantages and benefits of the present invention will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0033] In the attached diagram:

[0034] Figure 1 A flowchart illustrating a method for identifying blade tip timing asynchronous vibration parameters based on blade tip vibration acceleration, provided in an embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram of the blade tip timing sensor layout corresponding to the blade tip timing asynchronous vibration parameter identification method based on blade tip vibration acceleration provided in one embodiment of the present invention.

[0036] The present invention will be further explained below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0039] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0040] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0041] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0042] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0043] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0044] 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. Figures 1 to 2 As shown, a method for identifying timed asynchronous vibration parameters at the blade tip based on blade tip vibration acceleration includes,

[0045] In the first step S1, based on sensor layout optimization, the three blade timing sensors are mounted circumferentially on the engine casing at equal angles.

[0046] In the second step S2, the timing sensors at each blade tip are circumferentially mounted on the rotor blade casing. Under variable speed conditions, experiments are conducted to obtain the time sequence of each rotating rotor blade reaching the sensor.

[0047] In the third step S3, under different operating conditions of variable speed or constant speed, the arrival time of each rotor blade measured in each revolution is used as the dependent variable and the arrival angle of each rotor blade is used as the independent variable. Linear fitting is performed to reproduce the speed information of each revolution.

[0048] In the fourth step S4, the blade tip vibration acceleration is calculated based on the arrival time sequence and installation angle of the three adjacent blade tip timing sensors;

[0049] In step S5, an asynchronous vibration parameter identification model based on blade tip vibration acceleration is established;

[0050] In step S6, the asynchronous vibration frequency and amplitude are identified using the conventional full-blade spectrum method.

[0051] In step S7, using conventional methods, the asynchronous vibration frequency of the rotor blades is first identified using the MUSIC method. The vibration amplitude of the blades can then be obtained by using the identification results through the amplitude extraction and multi-signal classification method.

[0052] The blade tip timing parameter identification method for variable speed blade tip vibration acceleration, in the first step S1, requires the use of at least 3 blade tip timing sensor systems to obtain a set of blade tip vibration acceleration signals. Under the condition of meeting the actual situation, the smaller the included angle of each sensor, the better the accuracy. The 3 blade tip timing sensors are distributed at equal angles and the interval between each pair is less than 10°.

[0053] In the first step S2 of the method described above, under variable speed conditions, experiments are conducted to obtain the time series matrix of each rotating rotor blade reaching the sensor. Size N b *N×N p Among them, t i，j，n This represents the arrival time measured by the timing sensor at the i-th blade tip during the n-th rotation of the j-th blade. The rotor contains a total of N... b One blade, circumferentially mounted with N p A timing sensor at the leaf tip continuously collects data from N revolutions;

[0054] In the first step S3 of the method described above, since the blade tip timing system does not have a speed reference sensor installed, the reference speed of the rotor blade system is estimated by fitting the arrival time sequence measured by the blade tip timing sensor with the blade rotation angle. Given the unavoidable installation error of the blade tip timing sensor, the corresponding relationship between the blade arrival time and the rotation angle position is as follows: Among them, P i，j，n This indicates that the timing sensor at the i-th blade tip measures the angle of rotation of the j-th blade in the n-th revolution. The total number of rotor blades is N. b One blade, based on multimodal measurement, installed N p A leaf tip timing sensor, PA i Let BA be the installation angle of the i-th leaf tip timing sensor. j This represents the actual j-th installation interval;

[0055] In the method described above, the first step S3 specifically uses the blade arrival time as the dependent variable and the blade rotation angle as the independent variable, while also considering the influence of rotational speed fluctuations. Within a certain revolution, the rotational speed exhibits a linear variation, and the blade rotational speed is... The blade arrival time measured by multiple sensors in each revolution is fitted with the corresponding rotation angle using a quadratic function least squares method to obtain: in, The coefficients of the fitted quadratic function are obtained; after solving, the rotation period Y of each revolution is obtained. i，j，n Finally, the blade rotation speed was calculated.

[0056] In the first step S4 of the method described above, three consecutive circumferential leaf tip timing sensors are used, namely the i-th, i+1-th, and i+2-th sensors (i = 1, 2, ..., N). p -2) The actual arrival time t of the collected g-th leaf in the nth orbit. i，g，n , t j，g，n , t k，g，n The blade tip vibration velocity between two adjacent blade tip timing sensors can be calculated. Based on the blade tip vibration velocity, the i-th vibration acceleration value of the blade tip in the nth revolution can be calculated. in Represented as: Where R is the radius of rotation of the blade tip, f Ω The rotational frequency of the rotor blade system cannot be directly determined since the blade tip timing system does not have a speed reference sensor. θ i Let t be the installation angle of the i-th sensor. i，g，n This represents the arrival time of the g-th blade, collected by the i-th sensor in the n-th revolution;

[0057] In the first step S5 of the method described above, an asynchronous vibration parameter identification model based on blade tip vibration acceleration is established. The equation for blade vibration can be expressed as:

[0058] In the formula: M is the mass matrix, c is the damping matrix, K is the stiffness matrix, and ω1 is the fundamental frequency of the asynchronous vibration excitation force, which should satisfy ω1=2πEO1f r Therefore, the excitation order should satisfy Eo. n =nEO1, since EO1 is not an integer, therefore EO n It is also almost impossible for it to be an integer. The solution to this vibration equation is...

[0059] In the first step S6 of the method described above, the asynchronous vibration frequency and amplitude are identified using the full blade spectrum method, and the amplitude S of the blade response is determined. k and phase φ k Represented as: Where: N b The total number of blades on the bladed disk; ND is the nodal diameter related to the bladed disk vibration, with positive ND for positive traveling waves and negative ND for negative traveling waves; A ND and ψ ND The response amplitude and phase are given when the blade disk pitch diameter is ND; ND max For an even number of blades, the equation ND is satisfied. max =N b / 2, for odd-numbered blades, the equation ND is satisfied. max =(N b -1) / 2;NDmin For an even number of blades, the equation ND is satisfied. min =1-N b / 2, for odd-numbered blades, the equation ND is satisfied. max =-(N) b -1) / 2, for a single excitation frequency in a rotating reference frame, the above equation can be corrected to obtain the blade response as: In the formula f r Let f be the rotational frequency of the bladed disk. Assuming all blades vibrate at the same frequency, a spatial Fourier transform of the vibration displacement of consecutive blades yields the traveling wave response in the measurement reference frame, where f is the traveling wave frequency. tw Satisfy f tw =f b +NDf r f b This represents the vibration frequency of the blade. This is the whole-blade spectral analysis method. The sampling rate of this method is equal to the number of blades multiplied by the rotational frequency of the bladed disk. Generally, this sampling rate can reduce aliasing, and the increased spectral width can also improve the signal-to-noise ratio, making spectral peaks easier to identify.

[0060] In the method described above, in the first step S7, multiple segments of blade tip timing acceleration data of the same length are extracted as snapshots. The vector of the q-th snapshot can be expressed as: a(q)=[a(t J(q-1)+1 ) a(t J(q-1)+2) … a(t J(q-1)+M J is the number of leaf-end sensors in the circumferential layout; M is the length of the snap vector, which satisfies mod(M, J) = 0. The snap matrix is ​​further constructed as A = [a(1) a(2) … a(Q)];

[0061] In the method described above, in the first step S7, the autocorrelation matrix is ​​calculated based on the snapshot matrix. When the leaf tip timing data is acceleration, the sample autocorrelation matrix is: Perform eigenvalue decomposition on the autocorrelation matrix. Sort the eigenvalues ​​from largest to smallest. The eigenvectors corresponding to the first L eigenvalues ​​form the signal subspace s, and the eigenvectors corresponding to the remaining ML eigenvalues ​​form the noise subspace G, satisfying: S T When G = 0, by setting a threshold p, according to the formula... Determine the number of frequency components L of the real signal, set the frequency traversal interval and step size, perform frequency traversal, and the steering vector expression for a given frequency f is: Where τ m For the m-th time value in each snapshot, the pseudospectral amplitude expression corresponding to a given frequency is as follows:

[0062] In the first step S7 of the method described above, in order to identify the asynchronous vibration amplitude of the blade using the MUSIC method, it is necessary to analyze the autocovariance matrix of the timing signal at the blade tip, and represent the snapshot vector as: BΛ f a+w(q), where B=[b1(q)b2(q) … b K (q)], where w(q) = [w(t)] q1 ) w(t q2 … w(t) qM )] T Therefore, the sample autocorrelation matrix can be expressed as In the formula Λ a A diagonal matrix consisting of the squares of the amplitudes of each order satisfies... Let I be the variance of w(t); M Let Λ be an M-order identity matrix. In the sample covariance matrix, Λ a It contains information on the amplitude of blade vibration. Obtain the blade vibration amplitude

[0063] On the other hand, a blade tip timing asynchronous vibration parameter identification system based on blade tip vibration acceleration includes:

[0064] The sensor layout optimization module is responsible for determining the number of circumferentially mounted blade tip timing sensors and the installation angle and position layout of each blade tip timing sensor.

[0065] The blade arrival time measurement module conducts tests under variable speed conditions, measuring the arrival time sequence of each blade through timing sensors at each blade tip;

[0066] The 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, converting the timed physical quantity measured at the blade tip into blade tip vibration acceleration;

[0067] The blade asynchronous vibration parameter identification module identifies the asynchronous vibration frequency of the rotor blade using the full blade spectrum analysis method or the MUSIC method. Using the identification results, the vibration amplitude under blade rotational stall and surge conditions can be obtained through the amplitude extraction and multi-signal classification method.

[0068] This disclosure of blade tip timing measurement does not require the installation of a reference speed sensor or additional prior information. It achieves the identification of asynchronous vibration parameters of variable speed rotating blades by measuring blade tip vibration acceleration instead of traditional blade tip vibration displacement.

[0069] Finally, it should be noted that the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0070] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, 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 foregoing 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 method for identifying timed asynchronous vibration parameters at the blade tip based on blade tip vibration acceleration, characterized in that, It includes the following steps: In the first step S1, at least one set of three blade tip timing sensors is circumferentially mounted on the engine casing. The three blade tip timing sensors in a set are circumferentially mounted at equal angles and the interval between each pair is less than 10°. The second step, S2, is to acquire the time sequence of each rotating rotor blade reaching the blade tip timing sensor under variable speed conditions. In the third step S3, under different operating conditions of variable speed or constant speed, the arrival time of each rotor blade measured in each revolution is used as the dependent variable and the arrival angle of each rotor blade is used as the independent variable to perform linear fitting to reproduce the speed information of each revolution. The fourth step, S4, calculates the blade tip vibration acceleration based on the time series and installation angle of a set of three adjacent blade tip timing sensors. Step S5: Establish an asynchronous vibration parameter identification model based on blade tip vibration acceleration; Step S6: Based on the asynchronous vibration parameter identification model, the asynchronous vibration frequency and amplitude are identified using the full blade spectrum method. The amplitude of the blade response is then determined using the full blade spectrum method. and phase Represented as: In the formula: This represents the total number of blades on the leaf disc. For the pitch diameter related to bladed disk vibration, the positive traveling wave Positive and negative traveling waves Negative; and The blade disc diameter is The response amplitude and phase at that time; For an even number of blades, the equation is satisfied. For an odd number of blades, the equation is satisfied. ; For an even number of blades, the equation is satisfied. For an odd number of blades, the equation is satisfied. For a single excitation frequency in a rotating reference frame, the above equation can be modified to obtain the blade response as follows: In the formula Given the rotational frequency of the bladed disk, with all blades vibrating at the same frequency, a spatial Fourier transform of the vibrational displacement of consecutive blades yields the traveling wave response in the measurement reference frame, where the traveling wave frequency is [value missing]. satisfy , The vibration frequency of the blade; In the seventh step S7, based on the asynchronous vibration parameter identification model, the asynchronous vibration frequency of the rotor blades is first identified using the MUSIC method, and then the vibration amplitude of the blades is obtained through the identification results.

2. The method according to claim 1, characterized in that, In the second step S2, an experiment is conducted under variable speed conditions to obtain the time sequence matrix T of each rotating rotor blade reaching the blade tip timing sensor. ,in, Indicates the first The timing sensor at the tip of the first leaf measures the first The blade is in the... The arrival time of the rotation measurement of the rotor includes a total of One blade, circumferentially mounted A timing sensor at the leaf tip continuously collects data. Data from the circle.

3. The method according to claim 1, characterized in that, In the third step S3, the relationship between the blade arrival time and the rotation angle position is as follows: ,in, Indicates the first The timing sensor at the tip of the first leaf measured the... The blade is in the... The rotor blades have a total of [number] rotation angles within the circle. Each blade is installed based on multimodal measurement. A leaf tip timing sensor, For the first The installation angle of the timing sensor at the leaf tip. For the actual number Installation intervals.

4. The method according to claim 1, characterized in that, In the third step S3, the rotational speed within the circle changes linearly, and the blade rotational speed is... By fitting the blade arrival time measured by multiple blade tip timing sensors in each revolution with the corresponding rotation angle using a quadratic function least squares method, the following results are obtained: ,in, The coefficients of the fitted quadratic function are obtained; after solving, the rotation period of each revolution is obtained. The blade rotation speed was calculated. .

5. The method according to claim 1, characterized in that, In the fourth step S4, the timing sensors of three consecutive adjacent circumferential leaf tips within a set are used. No. No. and Number, , collect the first The blade is in the... Actual arrival time within the circle The blade tip vibration velocity between the two adjacent blade tip timing sensors is calculated. The blade tip is calculated in the th moment based on the blade tip vibration velocity. The first in the circle Each vibration acceleration value ,in Represented as: ,in, Let be the radius of rotation of the leaf tip. The blade rotational speed frequency, For the first The installation angle of each sensor, Indicates the first The sensor at the first The first circle collected The arrival time of blade number 1.

6. The method according to claim 1, characterized in that, In step S5, the asynchronous vibration parameter identification model, i.e., the blade vibration equation, is: In the formula: For the quality matrix, Here is the damping matrix. Here is the stiffness matrix. Asynchronous vibration excitation force fundamental frequency Incentive levels The solution to the vibration equation is , Indicates frequency switching.

7. The method according to claim 1, characterized in that, In step S7, multiple segments of the same length of blade tip timing acceleration data are captured as snapshots. Each snapshot vector is represented as: J represents the number of leaf-end sensors arranged circumferentially; Let be the length of the snapshot vector, satisfying The snapshot matrix is ​​constructed as follows: Calculate the autocorrelation matrix based on the snapshot matrix. When the leaf tip timing data is acceleration, the autocorrelation matrix is: Perform eigenvalue decomposition on the autocorrelation matrix, and sort the eigenvalues ​​from largest to smallest. The eigenvectors corresponding to each eigenvalue constitute the signal subspace. ,the remaining The eigenvectors corresponding to the eigenvalues ​​constitute the noise subspace. And satisfy: By setting a threshold According to the formula Determine the number of frequency components of the real signal Set the frequency traversal interval and step size, perform frequency traversal, and give a frequency. The expression for the steering vector is: ,in For each set of snapshots, the first The pseudospectral amplitude expression for a given time value and frequency is as follows: .

8. The method according to claim 1, characterized in that, In step S7, the MUSIC method is used to identify the asynchronous vibration amplitude of the blade. Specifically, the autocovariance matrix of the timing signal at the blade tip is analyzed, and the snapshot vector is represented as: In the formula ,in , , The sample autocorrelation matrix is ​​represented as In the formula A diagonal matrix consisting of the squares of the amplitudes of each order satisfies... ; for The variance; for An identity matrix of order 1 in the sample covariance matrix It contains information on the amplitude of blade vibration. The vibration amplitude of the blade was obtained. .

9. A system for implementing the blade tip timing asynchronous vibration parameter identification method based on blade tip vibration acceleration as described in any one of claims 1-8, characterized in that, It includes, The sensor layout optimization module is configured to determine the number of circumferentially mounted blade tip timing sensors and the installation angle and position layout of each blade tip timing sensor. The blade arrival time measurement module measures the arrival time sequence of each blade through timing sensors at each blade tip under variable speed conditions. The blade tip vibration acceleration calculation module is connected to the blade arrival time measurement module. The 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. The blade asynchronous vibration parameter identification module is connected to the blade tip vibration acceleration calculation module. The blade asynchronous vibration parameter identification module identifies the asynchronous vibration frequency of the rotor blade using the whole blade spectrum analysis method or the MUSIC method. Using the identification results, the vibration amplitude under the blade rotation stall and surge conditions is obtained through the amplitude extraction multi-signal classification method.

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