CN116953279A - Timing monitoring method and system for high-frequency vibration blade tip of turbine blade of aeroengine - Google Patents

Abstract

The method comprises the steps of collecting arrival and departure time sequences of the blade tips of a whole circle of blades passing through a blade tip timing sensor; calculating the actual speed of the blade tip of the turbine blade by using the time of the blade passing through the single sensor and the calculated actual linear displacement of the blade; the blade tip timing system does not need to be provided with a rotating speed reference sensor, and the arrival time or the departure time measured by the blade tip timing sensor is used for fitting with the installation angle of the sensor to reconstruct the rotating speed of the turbine rotor; obtaining the tip vibration speed through the calculated actual tip speed of the turbine blade and the turbine rotor rotating speed; determining a resonance area of blade vibration by using a single degree-of-freedom algorithm, and obtaining the vibration frequency and excitation order of the turbine blade based on a blade campbell diagram; and reconstructing a strain field of the turbine blade based on the vibration speed and the strain mode of each stage of blade tip of the turbine blade under the multiple physical fields, and reconstructing the strain field of the high-pressure turbine blade under the multiple physical fields.

Description

Timing monitoring method and system for high-frequency vibration blade tip of turbine blade of aeroengine

Technical Field

The application relates to the technical field of non-contact measurement of rotor blades of rotary machinery, in particular to a method and a system for timing monitoring of high-frequency vibration blade tips of turbine blades.

Background

The high-pressure turbine blade is the most severe part of the aeroengine which is subjected to heat, namely mechanical load, and is also a key safety part of the engine, so that the safety and reliability of the high-pressure turbine blade are guaranteed to have a non-underestimated effect on the flight safety. The turbine blade working condition is very severe in environment, the traditional contact measurement cannot be completed, and the strain gauge cannot work at such high temperature, so that the blade tip timing is used as a novel non-contact blade vibration on-line monitoring technology, and great interest of scientific researchers is brought. However, in the conventional tip timing system, a reference sensor is always installed at the rotating shaft to provide a time reference and realize measurement of the rotating speed, but due to the complexity of the aeroengine structure and insufficient space near the rotating shaft, the installation of the reference sensor is very difficult, so that the use of the tip timing method on the aeroengine is affected. If the reference sensor in the tip timing system can be removed, the safety and reliability of the aeroengine flight can be greatly improved, but the existing method for processing the tip timing data can be disabled. Therefore, the application provides a method for reconstructing the tip speed of the turbine blade by simultaneously utilizing the rising edge and the falling edge data of the tip timing signal, which lays a foundation for more extensive application of the tip timing technology in the future. Meanwhile, the conventional blade tip timing technology usually adopts direct calculation of blade vibration displacement, and vibration parameter identification is performed by using the displacement, but the identification effect on high-frequency vibration is poor. The turbine blades are relatively thick and complex in blade shape, and the first order natural frequency is typically above one kilohertz, which results in poor parameter identification of the turbine blade vibration using the reconstructed vibration displacement. Therefore, the application provides a method for reconstructing the vibration speed of the turbine blade, which can be used for more accurately identifying the high-frequency vibration. In the prior art, the blade tip timing technology generally only uses the arrival time corresponding to the rising edge triggered when the blade arrives at the sensor as a time sequence for calculation, and the application directly reconstructs the actual speed of the blade tip by using the arrival time and the departure time of the turbine blade from the sensor.

The above information disclosed in the background section is only for enhancement of understanding of the background of the application and therefore may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.

Disclosure of Invention

Aiming at the defects in the prior art, the application aims to provide a blade tip timing measurement technology which simultaneously utilizes the rising edge and the falling edge of a blade tip timing signal, and under the condition of not using a rotating speed reference sensor, the rotation speed of a blade rotor is fitted by utilizing the relationship between the arrival time and the installation angle of the blade tip timing measurement; meanwhile, the application changes the physical quantity of the traditional blade tip timing analysis from displacement to speed, so that the high-frequency vibration parameters of the turbine blade can be more accurately identified; meanwhile, the actual speed of the blade tip can be reconstructed by using one sensor by using the time of the turbine blade reaching and leaving the sensor, so that the data utilization rate is higher and the reconstructed speed is more accurate; the application also reconstructs the strain field of the turbine blade through the blade tip vibration speed of the turbine blade.

In order to achieve the above object, the present application provides the following technical solutions:

the application relates to a timing monitoring method for a high-frequency vibration blade tip of a turbine blade of an aeroengine, which comprises the following steps:

a first step S1, according to the working condition of the turbine blade of the aeroengine, determining the excited mode number M and recording the mode number M as f= [ f ] ₁ f ₂ … f _m ]The turbine blade is relatively thick, the blade shape is complex, and the first-order natural frequency of the turbine blade tends to be f ₁ Higher than 1000Hz, natural frequency f of other orders ₂ ，…，f _m High frequency up to 2000-5000 Hz; at the same time, the number N of the blade tip timing sensors is determined according to the number of modes _t Wherein N is _t The distribution angle and the position of the sensor are determined based on a particle swarm algorithm of the optimal layout of the sensor;

s2, the blade tip of the turbine blade of the aero-engine is of an H-shaped structure, and a time sequence of the turbine blade actually reaching and leaving the blade tip timing sensor is obtained based on data directly collected by the blade tip timing sensor;

step 3, calculating the actual linear displacement of the turbine blade tip reaching and leaving the blade tip timing sensor by utilizing the known blade thickness and the distance information from the blade tip to the rotating shaft of the turbine blade of the aero-engine, and calculating the actual linear speed of the turbine blade tip when rotating by combining the time sequence of the turbine blade actually reaching and leaving the blade tip timing sensor;

step S4, fitting out the rotating speed of the turbine rotor based on the time sequence of the turbine blade actually reaching or leaving the blade tip timing sensor and the installation angle of the corresponding blade tip timing sensor;

step S5, calculating the vibration speed of the blade tip of the turbine blade by using the actual speed of the blade tip of the turbine blade during rotation and the rotation speed of the turbine rotor, determining the resonance interval of blade vibration by using a single degree-of-freedom algorithm, and determining the vibration frequency and excitation order of the blade according to the prior information of the campbell diagram of the turbine blade;

s6, constructing a design matrix of a vibration equation according to different modal vibration frequencies and excitation orders of the turbine blade, and identifying and fitting vibration parameters of the turbine blade through a circumferential Fourier algorithm; the vibration parameters comprise the resonant rotating speed, the resonant frequency, the excitation order and the vibration amplitude of the blade;

s7, carrying out finite element analysis based on the resonance rotating speed of the blade and the actual working condition of the turbine blade, extracting the speed vibration mode and the strain vibration mode of each-order vibration, obtaining the position with the maximum stress when the turbine blade vibrates, and calculating the strain conversion coefficient between the tip timing measuring point and the position with the maximum tip vibration speed and the maximum stress of the whole turbine blade when each-order vibration;

and an eighth step S8, performing multi-physical-field strain field reconstruction on the high-pressure turbine blade based on the tip timing measurement point and the speed-strain conversion coefficient of the whole turbine blade during each-order vibration and the distinguished vibration parameters.

In the method, in the second step S2, a rotation test of the turbine blade is carried out, collected tip timing data is processed, a preset threshold value is selected to process collected original signals, and a time sequence that the turbine blade actually arrives at and leaves from a tip timing sensor is extracted from the original signals

The size is (N) _u *N _p )×(2*N _t ) Wherein->Indicating the arrival time of the ith blade tip timing sensor for measuring the nth blade rotation at the nth turn,/th blade tip timing sensor>Indicating the departure time of the ith blade tip timing sensor for measuring the nth blade rotation at the nth turn, N _u Representing the number of turbine blades in the rotor, N _p Represents the total number of turns collected by the rotor, N _t Representing the number of tip timing sensors.

In the third step S3, the thickness of the turbine blade is w, the distance R from the tip of the turbine blade to the center of the rotor rotating shaft is calculated, and the actual linear displacement D of the turbine blade passing through the single tip timing sensor during rotation is equal to

In the third step S3, the method is based on the arrival time of the same blade in the same circleAnd leave time->Calculating to obtain the actual linear velocity +.>

In the method, in the fourth step S4, the relationship between the rotation angle of the turbine blade and the actual arrival time is expressed as:wherein the rotation angle of the jth turbine blade measured by the ith blade tip timing sensor in the nth turn is omega _i，j，n ，N _u For the number of turbine blades, N _t For the number of tip timing sensors installed based on multi-modal measurements, θ _i SJ for the mounting angle of the ith tip timing sensor _j Is the actual j-th installation interval.

In the method, in the fourth step S4, the arrival time of the turbine blade is used as a dependent variable, the actual rotation angle of the turbine blade is used as a dependent variable, and the rotation speed of the turbine blade is linearly changed when the turbine blade rotates, so that the rotation speed of the turbine blade is the same as the dependent variableFitting the blade arrival time measured by a plurality of blade tip timing sensors in the same circle and the corresponding actual rotation angle by adopting a least square method to obtain: />Wherein->Coefficients of the fitted quadratic function; solving to obtain the rotation period of each circle as T _i，n，j Finally, calculating to obtain the rotation speed of the turbine rotor>

In the fifth step S5, the vibration speed of the reconstructed blade tip is calculatedWherein the method comprises the steps ofFor the actual speed of the turbine blade tip during rotation,/->Is the turbine rotor speed; and determining a resonance area of blade vibration by using a single degree-of-freedom algorithm, and obtaining the blade resonance rotating speed, the resonance frequency, the excitation order and the vibration amplitude by using a campbell diagram of the turbine blade as prior information.

In the method, in the sixth step S6, the vibration mode of the blade is single degree of freedom simple harmonic vibration, and the tip speed acquired by the tip timing sensor is expressed as:when the blade generates multi-mode resonance, the vibration of each mode is linearly overlapped by the property of the vibration of a linear system, and the blade tip speed acquired by the blade tip timing sensor is expressed as follows: />Wherein->A vibration coefficient representing an mth order tip vibration velocity signal; excitation order and tip timing sensor layout angle theta of blade obtained based on campbell diagram _i (i＝1，2，…，N _t ) Re-writing the expression of tip speed as: />Wherein n is _m For the number of modes actually involved, E _O，i For the excitation order corresponding to the vibration in the ith order mode, A _i ，B _i The vibration coefficient representing the ith order tip vibration velocity signal is the same as N _t Acquisition of N by several sensors _p The design matrix of the circle data is constructed as

In the method, in the sixth step S6, blade vibration parameters are calculated by using a circumferential Fourier algorithm, firstly, a vibration equation of the turbine blade is constructed, wherein a matrix formed by the actual rotation speed of the blade tip of the turbine blade obtained by V calculation during rotation is constructed,the ith-order speed amplitude u of the blade tip of the turbine blade is a matrix formed by vibration coefficients _i And phase->Satisfy->Secondly, can pass->Determining a vibration parameter, wherein->Refers to the generalized inverse of the design matrix.

In the method, in a seventh step S7, a finite element model of the turbine blade is subjected to modal analysis according to the calculated resonance rotating speed and actual high-temperature and high-pressure working conditions in a test, and the velocity vibration modes of each step of the tip timing measuring point are extracted according to the position and the direction of the tip timing sensor measuring pointWherein phi is _bbt，i Representing a certain-order speed vibration mode of actual participation vibration of blade tip timing sensor measuring points, n _m Is the actual number of modes; extracting strain vibration mode of each order of the whole turbine blade>Wherein->An ith order response mode representing actual participation of turbine blades in vibration, n _p Representing the total number of nodes when finite element analysis is performed; and based on the extracted speed U _bbt And the strain vibration mode V, calculating the speed-strain conversion coefficient of the blade tip timing measuring point and the whole turbine blade during the ith order vibration to be +.>

In the method, in the eighth step S8, the speed amplitude u is based on the ith-order vibration of the blade tip of the turbine blade _i Phase ofTip timing point and speed-strain conversion coefficient q of the whole turbine blade _i Reconstructing the strain field of the entire turbine blade during the ith vibration>The strain field in the multi-mode resonance is obtained by superposing the vibration strain fields of each order participating in the vibration, which is +.>

An aero-engine turbine blade high frequency vibratory tip timing monitoring system implementing the method includes,

a tip timing sensor layout optimization module configured to determine a number of tip timing sensors for measuring turbine blade vibrations and an optimal layout of tip timing sensors;

a blade arrival and departure time measurement module configured to collect a time series of blade arrival and departure tip timing sensors;

the turbine blade tip actual speed calculation module is connected with the blade arrival and departure time measurement module, and is configured to calculate the actual displacement of the turbine blade tip when the turbine blade tip actually arrives at and departs from the tip timing sensor by using the thickness of the blade and the distance information from the tip to the rotating shaft, and reconstruct the actual rotating speed of the turbine blade tip when the turbine blade tip rotates by combining the time sequence of the turbine blade actually arriving at and departs from the tip timing sensor;

the turbine blade rotor rotating speed fitting estimation module is connected with the turbine blade tip actual speed calculation module and is configured to measure the arrival time and the rotating angle of all blades passing through the tip timing sensor by utilizing all the tip timing sensors, and the turbine blade rotor rotating speed is obtained through fitting the corresponding relation between the angles and the time;

the turbine blade tip vibration speed calculation module is connected with the turbine blade rotor rotating speed fitting estimation module, and calculates the difference between the actual speed of the turbine blade tip and the rotating speed of the turbine blade rotor to obtain the turbine blade tip vibration speed;

the turbine blade vibration parameter identification module is connected with the turbine blade tip vibration speed calculation module, acquires the resonant rotating speed, the resonant frequency, the excitation order and the vibration amplitude of the turbine blade by using a single degree-of-freedom method and a campbell diagram, solves the vibration speed equation parameters by using a circumferential Fourier algorithm, and determines the amplitude and the phase of each-order vibration of the rotating turbine blade;

the turbine blade strain field reconstruction module is connected with the turbine blade vibration parameter identification module, and the turbine blade strain field reconstruction module utilizes the speed and the strain vibration mode obtained by finite element analysis to reconstruct to obtain a strain field in the actual working of the turbine blade, and monitors the stress level of the turbine blade.

Beneficial results

In the technical scheme, the method and the system for monitoring the timing of the high-frequency vibration blade tip of the turbine blade have the following beneficial effects: according to the method, the vibration speed of the blade tip of the turbine blade is calculated by using the arrival time and the departure time of the turbine blade passing through the sensor, so that the utilization rate of data is improved, and the monitoring cost is reduced; the application provides a blade tip technology without a reference sensor, which utilizes the arrival time and the rotation angle to fit the rotation speed of a turbine rotor blade system; meanwhile, the physical quantity analyzed at the previous blade tip timing is changed from displacement to speed, the process of calculating ideal arrival time is omitted, and the high-frequency vibration parameters of the turbine blade are more accurately identified; the application provides a strain field reconstruction method, which reconstructs the stress field of the whole blade through speed information of a blade end timing measuring point. Although the practical application object of the application is a turbine blade, the application has a huge application prospect on other blades.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments described in the present application, and other drawings may be obtained according to these drawings for a person having ordinary skill in the art.

Various other advantages and benefits of the present application will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the application. It is evident that the figures described below are only some embodiments of the application, from which other figures can be obtained without inventive effort for a person skilled in the art. Also, like reference numerals are used to designate like parts throughout the figures.

In the drawings:

FIG. 1 is a flow chart of a method for timing monitoring of high frequency vibratory tips of turbine blades according to one embodiment of the application;

FIG. 2 is a schematic diagram of a system for implementing the turbine blade high frequency vibratory tip timing monitoring method according to one embodiment of the present application;

FIG. 3 is a schematic illustration of a tip vibration speed measurement system based on tip timing without rotational speed reference in accordance with an embodiment of the present application;

FIG. 4 is a schematic view of a turbine end H-blade according to one embodiment of the present application;

FIG. 5 is a representative timing signal for a single blade of a high pressure turbine provided in accordance with one embodiment of the present application;

FIG. 6 is a schematic illustration of actual linear displacement calculation of a rotating turbine blade past a single tip timing sensor in accordance with one embodiment of the present application.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, based on the embodiments of the application, which are apparent to those of ordinary skill in the art without inventive faculty, are intended to be within the scope of the application.

Thus, the following detailed description of the embodiments of the application, as presented in the figures, is not intended to limit the scope of the application, as claimed, but is merely representative of selected embodiments of the application. All other embodiments, based on the embodiments of the application, which are apparent to those of ordinary skill in the art without inventive faculty, are intended to be within the scope of the application.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.

In the description of the present application, 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", "counterclockwise", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present application, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

In order to better understand the technical solution of the present application, the following description will be provided in detail with reference to fig. 1 to 6. The turbine blade high-frequency vibration blade tip timing monitoring method comprises the following steps:

the application relates to a timing monitoring method for a high-frequency vibration blade tip of a turbine blade of an aeroengine, which comprises the following steps:

in a first step S1, the number N of tip timing sensors to be mounted on a turbine blade casing is determined by analysis of the turbine blade operating conditions _t The method comprises the steps of carrying out a first treatment on the surface of the Determining the distribution angle and the position of the sensor based on the particle swarm algorithm rule of the optimal layout of the sensor;

in the second step S2, the application object of the method is an aero-engine high-pressure turbine blade, the blade tip of which is in a typical H-shaped structure, and the data directly collected by the blade tip timing sensor needs to be processed to obtain the time sequence of the turbine blade actually reaching and leaving each sensor;

in the third step S3, calculating the actual linear displacement of the blade tip of the turbine blade actually reaching and leaving each sensor by using the known thickness of the blade and the distance information from the blade tip to the rotating shaft, wherein the value is a constant value; the actual linear speed of the blade tip of the turbine blade during rotation is calculated by combining the time sequence information of the turbine blade actually reaching and leaving each sensor;

in a fourth step S4, the tip timing system in the method does not have a rotational speed sensor, and fits the rotational speed of the turbine rotor based on the time sequence of the turbine blade actually reaching or leaving each sensor and the installation angle of the corresponding sensor;

in the fifth step S5, the actual speed of the blade tip of the turbine blade during rotation and the rotation speed of the turbine rotor are utilized to calculate the vibration speed of the blade tip of the turbine blade, a single degree-of-freedom algorithm is used for determining the resonance interval of the blade vibration, and the vibration frequency and the excitation order of the blade are determined according to the prior information of the campbell diagram of the turbine blade; the compressed sensing algorithm, the autoregressive algorithm and the like can also identify the vibration frequency and the excitation order of the turbine blade;

in a sixth step S6, a design matrix of a vibration equation is constructed according to different modal vibration frequencies and excitation orders of the turbine blade, and fitted turbine blade vibration parameters are identified through a circumferential Fourier algorithm; the vibration parameters comprise the resonant rotating speed, the resonant frequency, the excitation order and the vibration amplitude of the blade;

in a seventh step S7, finite element analysis is carried out based on the resonance rotating speed of the blade and the actual working condition of the turbine blade, the speed vibration mode and the strain vibration mode of each-order vibration are extracted, the key position with the maximum stress when the turbine blade vibrates is obtained, and the strain conversion coefficient of the tip timing measuring point and the tip vibration speed of the whole turbine blade and the key position with the maximum stress when each-order vibration is calculated;

in the eighth step S8, the high-pressure turbine blade is subjected to multi-physical-field strain field reconstruction based on the tip timing measurement point at each vibration stage, the speed-strain conversion coefficient of the entire turbine blade, and the vibration parameters identified.

The method for monitoring the timing of the high-frequency vibration blade tip of the turbine blade is characterized in that in the first step S1, the number M of possible excited modes of the turbine blade in common working conditions is determined according to the working conditions of the turbine blade, and the number M is recorded as f= [ f ] ₁ f ₂ … f _m ]Because turbine blades are relatively thick and have complex blade shapes, the first order natural frequency of the turbine blade tends to be f ₁ Higher than 1000Hz, natural frequency f of other orders ₂ ，…，f _m High frequency up to 2000-5000 Hz; at the same time, the number N of the tip timing sensors is determined according to the number of the modes _t Wherein N is _t ≥2M；

In the method, in a first step S1, the number of sensors is determined to be N _t And after the excitation order of interest, optimizing the layout of the sensor based on a particle swarm algorithm and determining the final layout of the tip timing sensor, as schematically shown in FIG. 3, wherein S _t Representing the sensor position, θ _i The installation angle of the ith blade tip timing sensor;

the method is characterized in that in the second step S2, a rotation test of the turbine blade is carried out and collected tip timing data is processed, a schematic diagram of a single blade of the high-pressure turbine is shown in fig. 4, a schematic diagram of a typical tip timing signal of the single blade is shown in fig. 5, a most appropriate threshold value is selected according to the characteristics of the single blade, the collected original signal is processed, and a time sequence of the actual arrival and departure of the turbine blade from a sensor is extracted from the collected original signal

The size is (N) _u *N _p )×(2*N _t ) Wherein->Indicating the arrival time of the ith blade tip timing sensor for measuring the nth blade rotation at the nth turn,/th blade tip timing sensor>Indicating the departure time of the ith blade tip timing sensor for measuring the nth blade rotation at the nth turn, N _u Representing the number of turbine blades in the rotor, N _p Represents the total number of turns collected by the rotor, N _t Then represents the number of tip timing sensors that are ultimately determined;

the method is characterized in that in the third step S3, the actual linear displacement D of the turbine blade passing through the single blade tip timing sensor during rotation is calculated by knowing the thickness w of the turbine blade and the distance R from the blade tip of the turbine blade to the center of the rotor rotating shaft, and the value is equal toThe schematic diagram of the calculation principle is shown in fig. 6;

the method is characterized in that in the third step S3, according to the arrival time of the same blade in the same circleAnd leave time->Calculating to obtain the actual linear velocity of the blade tip of the turbine blade during rotation

The method is characterized in that in the fourth step S4, since the tip timing system of the method is not provided with a rotational speed sensor, it is required to be based on the bladeThe actual measured arrival time series (or departure time series) of the tip timing sensor is fitted to the rotational angle of the blade to obtain the turbine rotor rotational speed, and the relationship between the final rotational angle of the turbine blade and the actual arrival time can be expressed as:wherein the rotation angle of the jth turbine blade measured by the ith blade tip timing sensor in the nth turn is omega _i，j，n ，N _u For the number of turbine blades, N _t For the number of tip timing sensors installed based on multi-modal measurements, θ _i SJ for the mounting angle of the ith tip timing sensor _j The actual j-th installation interval;

the method is characterized in that in the fourth step S4, in order to fit the actual rotation speed and take into consideration the situation that the rotation speed may fluctuate during the test, the arrival time of the blade is used as a dependent variable, the actual rotation angle of the blade is used as a dependent variable, and the rotation speed of the turbine blade is set to linearly change during rotation, namely the rotation speed of the turbine blade is set to beFitting the blade arrival time measured by a plurality of sensors in the same circle and the corresponding actual rotation angle by adopting a least square method to perform a quadratic function, and obtaining: />Wherein->Coefficients of the fitted quadratic function; solving to obtain the rotation period of each circle as T _i，n，j Finally calculating to obtain the rotation speed of the turbine rotor

The method is characterized in that in a fifth step S5, a reconstruction is calculatedVibration speed of blade tipWherein->For the actual speed of the turbine blade tip during rotation,/->Is the turbine rotor speed; firstly, determining a resonance area of blade vibration by using a single degree-of-freedom algorithm, and obtaining the resonant rotating speed, resonant frequency, excitation order and vibration amplitude of the blade by using a campbell diagram of the turbine blade as prior information;

in the sixth step S6, the vibration mode of the blade is assumed to be single-degree-of-freedom simple harmonic vibration, so that when the blade is subjected to a certain mode resonance, the tip speed acquired by the sensor can be expressed as:when the blade generates multi-mode resonance, the vibration of each mode can be linearly overlapped through the vibration property of a linear system, and the blade tip speed acquired by the sensor is expressed as follows:wherein->A vibration coefficient representing an mth order tip vibration velocity signal; the excitation order of the blade has been obtained from the campbell plot in the previous step, and the layout angle θ of the individual sensors has been known _i (i＝1，2，…，N _t ) The expression for tip speed is rewritten to simplify the rewriting as:wherein n is _m For the number of modes actually involved, E _O，i For vibrations in the ith order modeCorresponding excitation order, A _i ，B _i The vibration coefficient representing the ith order tip vibration velocity signal is the same as N _t Acquisition of N by several sensors _p The design matrix of circle data can be constructed as

The method is characterized in that in the sixth step S6, blade vibration parameters are calculated by utilizing a circumferential Fourier algorithm, firstly, a vibration equation of the turbine blade is constructed, wherein a matrix formed by the actual rotation speed of the blade tip of the turbine blade obtained by V calculation during rotation is constructed,the ith-order speed amplitude u of the blade tip of the turbine blade is a matrix formed by vibration coefficients _i And phase->Satisfy->Secondly, can pass->Determining a vibration parameter, wherein->Refers to the generalized inverse of the design matrix;

the method is characterized in that in the seventh step S7, the finite element model of the turbine blade is subjected to modal analysis according to the calculated resonance rotating speed and actual high-temperature and high-pressure working conditions in the test, and the velocity vibration mode U of each step of the tip timing point is extracted according to the position and the direction of the tip timing sensor measuring point _bbt ＝[φ _bbt，1 φ _bbt，2 … φ _bbt，nm ]Wherein phi is _bbt，i Representing a certain-order speed vibration mode of actual participation vibration of blade tip timing sensor measuring points, n _m Is true toNumber of inter-modal; extracting strain vibration mode of each order of whole turbine bladeWherein->An ith order response mode representing actual participation of turbine blades in vibration, n _p Representing the total number of nodes when finite element analysis is performed; and based on the extracted speed U _bbt And the strain vibration mode V, calculating the speed-strain conversion coefficient of the blade tip timing measuring point and the whole turbine blade during the ith order vibration to be +.>

The method is characterized in that in the eighth step S8, the speed amplitude u is based on the ith-order vibration of the blade tip of the turbine blade _i Phase ofTip timing point and speed-strain conversion coefficient q of the whole turbine blade _i Reconstructing the strain field of the entire turbine blade during the ith vibration>The strain field in the multi-mode resonance can be obtained by superposing the vibration strain fields of each order participating in the vibration, which is +.>

According to another aspect of the application, an aircraft engine turbine blade high frequency vibratory tip timing monitoring system includes:

the blade tip timing sensor layout optimization module is used for determining the number of blade tip timing sensors and the optimal layout of the sensors for measuring the vibration of the rotating turbine blade;

the blade arrival and departure time measurement module is used for carrying out test on the basis of the circumferential layout of the blade tip timing sensor to acquire a time sequence of the blade arrival and departure sensor;

the actual speed calculation module of the blade tip of the turbine blade calculates the actual displacement of the blade tip of the turbine blade actually reaching and leaving each sensor by using the known thickness of the blade and the distance information between the blade tip and the rotating shaft, and reconstructs the actual rotating speed of the blade tip of the turbine blade when rotating by combining the time sequence information of the blade tip of the turbine blade actually reaching and leaving each sensor;

the turbine blade rotor rotating speed fitting estimation module is used for measuring the arrival time and the rotating angle of all blades passing through the blade tip timing sensor by utilizing all blade tip timing sensors, and obtaining the reference rotating speed of the rotor system through fitting the corresponding relation between the angle and the time;

the turbine blade tip vibration speed calculation module is used for calculating the difference between the actual speed of the turbine blade tip and the rotational speed of the turbine blade rotor to obtain the turbine blade tip vibration speed;

the turbine blade vibration parameter identification module is used for acquiring the resonant rotating speed, the resonant frequency, the excitation order and the vibration amplitude of the turbine blade by using a single degree-of-freedom method and a campbell diagram; solving vibration speed equation parameters by using a circumferential Fourier algorithm, and determining the amplitude and phase of each-order vibration of the rotating turbine blade;

and the turbine blade strain field reconstruction module is used for reconstructing a strain field obtained in actual working of the turbine blade by utilizing the speed and the strain vibration mode obtained by finite element analysis and monitoring the stress level of the turbine blade.

Finally, it should be noted that: the described embodiments are intended to be illustrative of only some, but not all, of the embodiments of the present application and, based on the embodiments herein, all other embodiments that may be made by those skilled in the art without the benefit of the present disclosure are intended to be within the scope of the present application.

While certain exemplary embodiments of the present application have been described above by way of illustration only, it will be apparent to those of ordinary skill in the art that modifications may be made to the described embodiments in various different ways without departing from the spirit and scope of the application. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive of the scope of the application, which is defined by the appended claims.

Claims (12)

1. The method for monitoring the timing of the high-frequency vibration blade tip of the turbine blade of the aeroengine is characterized by comprising the following steps of:

a first step S1, according to the working condition of the turbine blade of the aeroengine, determining the excited mode number M and recording the mode number M as f= [ f ] ₁ f ₂ … f _m ]Its first order natural frequency f ₁ Higher than 1000Hz, natural frequency f of other orders ₂ ，…，f _m High frequency of 2000-5000 Hz; at the same time, the number N of the blade tip timing sensors is determined according to the number of modes _t Wherein N is _t The distribution angle and the position of the sensor are determined based on a particle swarm algorithm of the optimal layout of the sensor;

s2, the blade tip of the turbine blade of the aero-engine is of an H-shaped structure, and a time sequence of the turbine blade actually reaching and leaving the blade tip timing sensor is obtained based on data directly collected by the blade tip timing sensor;

step 3, calculating the actual linear displacement of the turbine blade tip reaching and leaving the blade tip timing sensor by utilizing the known blade thickness and the distance information from the blade tip to the rotating shaft of the turbine blade of the aero-engine, and calculating the actual linear speed of the turbine blade tip when rotating by combining the time sequence of the turbine blade actually reaching and leaving the blade tip timing sensor;

step S4, fitting out the rotating speed of the turbine rotor based on the time sequence of the turbine blade actually reaching or leaving the blade tip timing sensor and the installation angle of the corresponding blade tip timing sensor;

step S5, calculating the vibration speed of the blade tip of the turbine blade by using the actual speed of the blade tip of the turbine blade during rotation and the rotation speed of the turbine rotor, determining the resonance interval of blade vibration by using a single degree-of-freedom algorithm, and determining the vibration frequency and excitation order of the blade according to the prior information of the campbell diagram of the turbine blade;

s6, constructing a design matrix of a vibration equation according to different modal vibration frequencies and excitation orders of the turbine blade, and identifying and fitting vibration parameters of the turbine blade through a circumferential Fourier algorithm; the vibration parameters comprise the resonant rotating speed, the resonant frequency, the excitation order and the vibration amplitude of the blade;

s7, carrying out finite element analysis based on the resonance rotating speed of the blade and the actual working condition of the turbine blade, extracting the speed vibration mode and the strain vibration mode of each-order vibration, obtaining the key position with the maximum stress when the turbine blade vibrates, and calculating the tip timing measuring point and the tip vibration speed and the strain conversion coefficient of the position with the maximum stress of the whole turbine blade when each-order vibration;

and an eighth step S8, performing multi-physical-field strain field reconstruction on the high-pressure turbine blade based on the tip timing measurement point and the speed-strain conversion coefficient of the whole turbine blade during each-order vibration and the distinguished vibration parameters.

2. The method according to claim 1, wherein in the second step S2, preferably, a rotational test of the turbine blade is performed and the collected tip timing data is processed, a predetermined threshold value is selected to process the collected raw signal, and a time series of actual arrival and departure of the turbine blade from the tip timing sensor is extracted therefrom

The size is (N) _u *N _p )×(2*N _t ) Wherein->Indicating the arrival time of the ith blade tip timing sensor for measuring the nth blade rotation at the nth turn,/th blade tip timing sensor>Indicating the departure time of the ith blade tip timing sensor for measuring the nth blade rotation at the nth turn, N _u Representing the number of turbine blades in the rotor, N _p Representing the rotor being collectedTotal number of turns, nt, represents the number of tip timing sensors.

3. The method according to claim 1, wherein in the third step S3, the turbine blade thickness is w, the distance R of the turbine blade tip from the center of the rotor shaft is calculated, and the actual linear displacement D of the turbine blade through the single tip timing sensor during rotation is equal to

4. A method according to claim 3, characterized in that in the third step S3, the arrival time of the same blade in the same turn is based onAnd leave time->Calculating to obtain the actual linear velocity of the blade tip of the turbine blade during rotation

5. The method according to claim 1, wherein in the fourth step S4, the relation between the turbine blade rotation angle and the actual arrival time is expressed as:wherein the rotation angle of the jth turbine blade measured by the ith blade tip timing sensor in the nth turn is omega _i，j，n ，N _u For the number of turbine blades, N _t For the number of tip timing sensors installed based on multi-modal measurements, θ _i SJ for the mounting angle of the ith tip timing sensor _j Is the actual j-th installation interval.

6. The method according to claim 1, wherein in the fourth step S4, the arrival time of the turbine blade is used as a dependent variable, the actual rotation angle of the turbine blade is used as a dependent variable, the rotation speed of the turbine blade is linearly changed when the turbine blade rotates, and the rotation speed of the turbine blade is set to beFitting the blade arrival time measured by a plurality of blade tip timing sensors in the same circle and the corresponding actual rotation angle by adopting a least square method to obtain:

wherein->Coefficients of the fitted quadratic function; solving to obtain the rotation period of each circle as T _i，n，j Finally, calculating to obtain the rotation speed of the turbine rotor>

7. The method according to claim 1, wherein in a fifth step S5, the vibration speed of the reconstructed blade tip is calculatedWherein->For the actual speed of the turbine blade tip during rotation,/->Is the turbine rotor speed; the resonance region of the blade vibration is determined using a single degree of freedom algorithm, and the campbell diagram of the turbine blade is utilized as a priori information,and obtaining the resonant rotating speed, resonant frequency, excitation order and vibration amplitude of the blade.

8. The method according to claim 1, wherein in the sixth step S6, the vibration form of the blade is single degree of freedom simple harmonic vibration, and the tip speed acquired by the tip timing sensor is expressed as:

when the blade generates multi-mode resonance, the vibration of each mode is linearly overlapped by the property of the vibration of a linear system, and the blade tip speed acquired by the blade tip timing sensor is expressed as follows:wherein->A vibration coefficient representing an mth order tip vibration velocity signal, f _m The vibration frequency of the blade tip vibration of the mth order is set, and t is the vibration time; excitation order and tip timing sensor layout angle theta of blade obtained based on campbell diagram _j (j＝1，2，…，N _t ) Re-writing the expression of tip speed as:wherein n is _m For the number of modes actually involved, E _O，i For the excitation order corresponding to the vibration in the ith order mode, A _i ，B _i The vibration coefficient of the ith order blade tip vibration speed signal is represented, j is the number of the blade tip timing sensor, and is the same as N _t Acquisition of N by several sensors _p The design matrix of the circle data is constructed as

9. A method according to claim 1, wherein in a sixth step S6, blade vibration parameters are calculated by means of a circumferential Fourier algorithm, and the vibration equation of the turbine blade is first constructed as a matrix of actual rotational speeds of the blade tips of the turbine blade obtained by the calculation V during rotation,the ith-order speed amplitude u of the blade tip of the turbine blade is a matrix formed by vibration coefficients _i And phase->Satisfy->Secondly, can pass->Determining a vibration parameter, wherein->Refers to the generalized inverse of the design matrix.

10. The method according to claim 1, wherein in the seventh step S7, a finite element model of the turbine blade is subjected to modal analysis according to the calculated resonance rotation speed and actual high-temperature and high-pressure working conditions in the test, and a velocity vibration mode of each step of the tip timing point is extracted according to the position and the direction of the tip timing sensor pointWherein phi is _bbt,i Representing a certain-order speed vibration mode of actual participation vibration of blade tip timing sensor measuring points, n _m Is the actual number of modes; extracting strain vibration mode of each order of the whole turbine blade>Wherein->An ith order response mode representing actual participation of turbine blades in vibration, n _p Representing the total number of nodes when finite element analysis is performed; and based on the extracted speed U _bbt And the strain vibration mode V, calculating the speed-strain conversion coefficient of the blade tip timing measuring point and the whole turbine blade during the ith order vibration to be +.>

11. The method of claim 1, wherein in an eighth step S8, the speed magnitude u is based on an ith vibration of the turbine blade tip _i Phase ofTip timing point and speed-strain conversion coefficient q of the whole turbine blade _i Reconstructing the strain field of the entire turbine blade during the ith vibration>The strain field in the multi-mode resonance is obtained by superposing the vibration strain fields of each order participating in the vibration, which is +.>

12. An aircraft engine turbine blade dither tip timing monitoring system that implements the method of any of claims 1-11, comprising,

a tip timing sensor layout optimization module configured to determine a number of tip timing sensors for measuring turbine blade vibrations and an optimal layout of tip timing sensors;

a blade arrival and departure time measurement module configured to collect a time series of blade arrival and departure tip timing sensors;

the turbine blade tip actual speed calculation module is connected with the blade arrival and departure time measurement module, and is configured to calculate the actual displacement of the turbine blade tip when the turbine blade tip actually arrives at and departs from the tip timing sensor by using the thickness of the blade and the distance information from the tip to the rotating shaft, and reconstruct the actual rotating speed of the turbine blade tip when the turbine blade tip rotates by combining the time sequence of the turbine blade actually arriving at and departs from the tip timing sensor;

the turbine blade rotor rotating speed fitting estimation module is connected with the turbine blade tip actual speed calculation module and is configured to measure the arrival time and the rotating angle of all blades passing through the tip timing sensor by utilizing all the tip timing sensors, and the turbine blade rotor rotating speed is obtained through fitting the corresponding relation between the angles and the time;

the turbine blade tip vibration speed calculation module is connected with the turbine blade rotor rotating speed fitting estimation module, and calculates the difference between the actual speed of the turbine blade tip and the rotating speed of the turbine blade rotor to obtain the turbine blade tip vibration speed;

the turbine blade vibration parameter identification module is connected with the turbine blade tip vibration speed calculation module, acquires the resonant rotating speed, the resonant frequency, the excitation order and the vibration amplitude of the turbine blade by using a single degree-of-freedom method and a campbell diagram, solves the vibration speed equation parameters by using a circumferential Fourier algorithm, and determines the amplitude and the phase of each-order vibration of the rotating turbine blade;

the turbine blade strain field reconstruction module is connected with the turbine blade vibration parameter identification module, and the turbine blade strain field reconstruction module utilizes the speed and the strain vibration mode obtained by finite element analysis to reconstruct to obtain a strain field in the actual working of the turbine blade, and monitors the stress level of the turbine blade.