Multi-mode blade tip timing measurement method and system based on blade tip speed

Abstract

Disclosed is a multi-modal blade tip timing measurement method and system based on blade tip speed. The method includes: installing blade tip timing sensors in groups of two circumferentially on a rotor blade casing, obtaining a time series of a whole circle of rotor blades reaching the sensor, and obtaining the rotation speed of each circle based on the time series; obtaining the blade tip vibration speed according to the arrival time collected by the two adjacent sensors and the installation angle of the sensor, and converting the blade tip timing analysis physical quantity into the blade tip vibration speed; constructing a sparse representation model of the undersampled blade tip timing speed signal based on the blade tip vibration speed signal, and solving to determine the blade multi-modal vibration frequency; using the non-zero element position of the sparse solution to extract the elements of the measurement matrix to construct the vibration equation of the blade tip speed, and identifying the vibration amplitude of the blade multi-modality through the least squares algorithm. The present disclosure does not require the installation of a rotation speed reference sensor, and further improves the recognition accuracy of the blade multi-modality.

Description

Technical Field

[0001] The present invention relates to the technical field of non-contact measurement of rotor blades of rotating machinery, and in particular to a multi-modal blade tip timing measurement method and system based on blade tip speed. Background Art

[0002] As one of the key components of aero-engines, the structural integrity of blades directly affects the safe operation of engines. Due to the harsh working environment and frequent changes in working conditions of blades, the vibration loads they bear are very complex. Under certain special working conditions, blades will resonate and alternating stresses of multi-order modal coupling vibrations will appear at specific locations, that is, at a certain speed, multiple vibration modes are excited at the same time, which will cause high-cycle fatigue failure of blades. Therefore, it is very important to monitor blades online under multi-modal resonance. Conventional strain gauge measurement methods can provide limited vibration information and are prone to failure under harsh working conditions of aero-engines; blade tip timing technology has received more and more attention as a non-contact measurement method. This method can measure the entire circle of blades, but currently blade tip timing measurement mainly identifies blade vibration parameters from blade tip displacement. However, since displacement measurement gives the highest weight to low-frequency components, frequency identification is generally more accurate in the low-frequency range or less than 1000 Hz, and multi-modal identification faces huge challenges. In addition, the blade tip vibration displacement inevitably causes steady-state motion or trend items of displacement due to the existence of measurement position error and speed fluctuation, which further affects the accuracy of parameter identification. Therefore, the present invention provides a measurement method and system for converting the traditional blade tip timing analysis physical quantity from blade tip vibration displacement to blade tip vibration velocity, so as to improve the accuracy of blade multi-modal vibration parameter identification.

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

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a full-frequency domain blade tip timing vibration parameter identification method and system, to solve the problem of multi-modal vibration parameter identification based on blade tip displacement in the existing blade tip timing software system, to analyze the physical quantity converted from blade tip vibration displacement to blade tip vibration velocity, and to improve the accuracy of blade multi-modal vibration parameter identification.

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

[0006] A multi-mode blade tip timing measurement method based on blade tip speed of the present invention comprises:

[0007] The first step S100: installing blade tip timing sensors in groups of two circumferentially on the rotor blade casing, obtaining a time sequence of a whole circle of rotor blades reaching the blade tip timing sensors, and obtaining a rotation speed of each circle based on the time sequence;

[0008] The second step S200: obtaining the blade tip vibration speed according to the arrival time collected by two adjacent sensors, the installation angle of the blade tip timing sensor and the rotation speed;

[0009] The third step S300: constructing a sparse representation model V of the undersampled blade tip timing velocity signal based on the blade tip vibration velocity, and obtaining a sparse solution to determine the blade multi-modal vibration frequency, wherein the sparse representation model is v=Φ c , where Φ is the measurement matrix and c is the unknown coefficient vector;

[0010] Fourth step S400: construct a design matrix using the positions of non-zero elements of the sparse solution, extract elements of the measurement matrix to construct a vibration equation of the blade tip speed, and identify the vibration amplitude of the multi-mode of the rotor blade via a least squares algorithm based on the design matrix and the vibration equation.

[0011] In the method described above, in the first step S100, the number of circumferential blade tip timing sensors installed is N. p The multimodal number M of the rotor blade is determined by, where N p ≥2M.

[0012] In the method described, in the first step S100, the installation angle interval between the blade tip timing sensors in a group of two is less than 10°.

[0013] In the method described above, in the first step S100, an OPR speed sensor is installed to obtain the key phase signal time series t of the nth round of the key phase signal. OPR，n , based on the key phase signal time series, the rotation speed of the rotor blade at the nth turn is calculated

[0014] In the method described, in the first step S100, the relationship between the arrival time and the rotation angle position of the rotor blade is: Among them, A i，j Where is the angular position of the jth blade arrival time measured by the i-th blade tip timing sensor. There are a total of N rotor blades. b blades, N p is the number of blade tip timing sensors installed, PA i is the installation angle of the i-th blade tip timing sensor, BA j is the actual j-th installation interval;

[0015] The rotation speed in the circle changes linearly, and the blade speed is: The rotation angle of the rotor blade is represented by a quadratic function fitting After solving, we get the rotation period T of each circle. i，j，n , calculate the blade speed According to N p N measured by the blade tip timing sensors b The actual arrival time of the leaf is t i，b，n , the reference speed f in the nth circle Ω for: Among them, there are N rotor blades in total. b blades, based on multi-modal measurement installation N p A blade tip timing sensor collects N consecutive laps of data.

[0016] In the method described above, in the second step S200, according to the arrival time t collected by the blade tip timing sensor i i，j，n , the arrival time t collected by the adjacent blade tip timing sensor i+1 i+1，j，n , the installation angle interval of the blade tip timing sensor Δθ i，i+1 =θ i+1 -θ i And the rotation speed to obtain the blade tip vibration speed Wherein, R is the rotation radius from the rotor blade tip rotation axis to the blade tip.

[0017] In the method, in the third step S300, the blade tip vibration speed is It is expressed as the vibration coefficient of the m-th order blade tip vibration velocity. The sparse representation model of the under-sampled blade tip timing blade tip velocity signal is constructed using the sparse theory:

[0018]

[0019] in, is the average arrival time of blade b collected by the two adjacent blade tip timing sensors at the nth round, i and i+1, f Δl =l×f Δ1 For a fixed interval f Δ1 The l frequency component under is used to estimate the blade vibration frequency; the sparse representation model is expressed as v = Φ c , where Φ is the measurement matrix and c is the unknown coefficient vector.

[0020] In the method described, in the third step S300, by solving the combinatorial optimization problem sparse solution The greedy algorithm is used to approximate the sparse vector c = [c1 c2 ... c 2l-1 c 2l ] T ,like and If the rth group is not zero, the vibration equation of the rotor blade of the rth order can be expressed as Among them, the multi-modal resonance frequency of the rotor blade is f r =f Δ1 *l.

[0021] In the method described above, in the fourth step S400, a design matrix H is constructed by locating non-zero elements in the sparse representation model, and a least squares algorithm is used to solve The vibration amplitude and phase of the blade are obtained based on the relationship between velocity and displacement, where: It is represented by the vibration amplitude of the blade at the rth order identified by the blade tip speed and represents the vibration phase of the blade at the rth order.

[0022] A system for implementing a multi-modal blade tip timing measurement method based on blade tip speed includes,

[0023] a blade tip arrival time measurement module configured to obtain a time sequence of a full revolution of rotor blades arriving at a blade tip timing sensor;

[0024] A blade reference speed calculation module, which is connected to the blade tip arrival time measurement module, and the blade reference speed calculation module obtains the speed of each circle based on the time series;

[0025] a blade tip vibration speed calculation module, which is connected to the blade tip arrival time measurement module and the blade tip arrival time measurement module, and the blade tip vibration speed calculation module obtains the blade tip vibration speed according to the arrival time collected by two adjacent sensors, the installation angle of the blade end timing sensor and the rotation speed;

[0026] The under-sampling signal processing module is connected to the blade tip vibration velocity calculation module. The under-sampling signal processing module establishes a sparse representation model of the under-sampling blade tip vibration velocity, determines the multi-modal resonance frequency of the blade by sparse solution, and constructs a design matrix based on the positioning of non-zero elements of the sparse solution, and identifies the vibration amplitude and phase of the blade multi-mode by a least squares algorithm.

[0027] Beneficial Effects

[0028] Unlike traditional methods that focus on identifying vibration parameters from blade tip vibration displacement measurements, the blade tip timing analysis of this patent uses blade tip vibration velocity. This change eliminates the impact of speed fluctuations during calculations under variable speed conditions and weakens the trend or stable offset of blade tip vibration velocity relative to blade tip vibration displacement. Therefore, this method can more easily identify blade resonance without prior information. In addition, this method uses tip velocity measurements to more easily enhance the mid-frequency vibration amplitude weights, thereby facilitating the identification of multi-modal vibration parameters of rotor blades, which is of great significance to the application of non-contact measurement systems for rotor blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0030] By reading the detailed description of the preferred specific embodiments below, various other advantages and benefits of the present invention will become clear to those of ordinary skill in the art. The drawings in the specification are only for the purpose of illustrating the preferred embodiments and are not considered to be limitations of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative work. Moreover, the same reference numerals are used throughout the drawings to represent the same components.

[0031] In the attached picture:

[0032] Figure 1 A schematic flow chart of a method for identifying full-frequency-domain vibration parameters based on blade tip timing provided by an embodiment of the present invention;

[0033] Figure 2 A schematic diagram of the structure of a system for implementing the blade tip timing-based full-frequency domain vibration parameter identification method provided in one embodiment of the present invention;

[0034] Figure 3 A schematic diagram of calculating blade tip vibration velocity based on the installation angles of two adjacent blade tip timing sensors provided by an embodiment of the present invention;

[0035] Figure 4 A schematic diagram of the circumferential angle installation position of a blade tip timing sensor provided by an embodiment of the present invention;

[0036] FIG5(a) and FIG5(b) are schematic diagrams of a blade reference speed for a speed reference-free fitting evaluation provided by an embodiment of the present invention, FIG5(a) is a comparison between the blade speed estimated by fitting and the measured result, and FIG5(b) is a relative error of the fitting speed corresponding to each revolution compared with the measured result;

[0037] FIG6(a) and FIG6(b) are schematic diagrams of measured blade vibration responses provided by an embodiment of the present invention, FIG6(a) is a conventional blade tip vibration displacement; FIG6(b) is a blade tip vibration velocity response;

[0038] Figures 7(a) and 7(b) are schematic diagrams of blade vibration frequency identification results provided by an embodiment of the present invention. Figure 7(a) is the identification result based on the traditional blade tip vibration displacement blade tip timing parameter table; Figure 7(b) is the identification result based on the blade tip vibration velocity response blade tip timing parameter table.

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

[0040] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Therefore, the following Figure 1 to Figure 7(b) The detailed description of the embodiments of the present invention provided in the present invention is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

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

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

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

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

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

[0047] In order to enable those skilled in the art to better understand the technical solution of the present invention, Figure 1 -7 further introduces the present invention in detail. A multi-modal blade tip timing measurement method based on blade tip speed includes:

[0048] In the first step S100, blade tip timing sensors are circumferentially mounted on the rotor blade casing in groups of two, and a time sequence of a whole circle of rotor blades reaching the sensors is obtained, and a rotation speed of each circle is obtained based on the time sequence;

[0049] S400: Utilizing the non-zero element positions of the sparse solution, extracting elements of the measurement matrix to construct a vibration equation of the blade tip velocity, and identifying the vibration amplitude of the blade multi-mode by a least squares algorithm.

[0050] In the second step S200, the blade tip vibration velocity is obtained according to the arrival time collected by the two adjacent sensors and the installation angle of the sensors, and the blade tip timing analysis physical quantity is converted into the blade tip vibration velocity;

[0051] In the third step S300, based on the blade tip vibration velocity signal, a sparse representation model of the under-sampled blade tip timing velocity signal is constructed to solve and determine the blade multi-modal vibration frequency;

[0052] In the fourth step S400, the non-zero element positions of the sparse solution are used to extract elements of the measurement matrix to construct a vibration equation of the blade tip velocity, and the vibration amplitude of the blade multi-mode is identified by a least squares algorithm.

[0053] In the multi-modal blade tip timing measurement method based on blade tip speed, in the first step S100, the number of circumferential blade tip timing sensors installed for measuring the blade tip vibration speed of the rotor blade tip is N. p The multimodal number M of the rotor blade is determined by, where N p ≥2M, mainly two adjacent blade tip timing sensors.

[0054] In the method described, in the first step S100, the angle interval between the two adjacent blade tip timing sensors affects the calculation accuracy of the blade tip speed, so the smaller the angle interval is, the higher the accuracy is under the condition of satisfying the actual situation.

[0055] S101, the blade tip timing system installs the OPR reference sensor and obtains the time series t of the nth circle of the key phase signal OPR，n , based on the time series of the key phase signal, the speed of the rotor blade at the nth turn is calculated

[0056] S102: The blade tip timing system is not equipped with an OPR reference sensor. The blade reference speed is estimated based on the arrival time sequence measured by the blade tip timing sensor and the rotation angle of the blade. In addition, due to the inevitable installation error of the blade tip timing sensor, the corresponding blade arrival time and rotation angle position relationship is: Among them, A i，j Where is the angular position of the jth blade arrival time measured by the i-th blade tip timing sensor. There are a total of N rotor blades. b blades, based on multi-modal measurement installation N p Tip timing sensors, Pa i is the installation angle of the i-th blade tip timing sensor, BA j is the actual j-th installation interval;

[0057] S1021, based on the one-to-one correspondence between the blade arrival time and the rotation angle, the blade speed is constant in the nth circle, the blade rotation angle is used as the dependent variable, and the blade arrival time is used as the independent variable. Due to the complex factors in the actual operation environment of the engine, the speed will inevitably fluctuate. In order to ensure the accuracy of the speed estimation, it is necessary to consider the impact of the fluctuation on the fitting result. Assuming that the speed changes linearly in a circle, the blade speed is: f Ω =at+b, the blade rotation angle can be expressed by quadratic function fitting Let A i，j，n =360°After solving, we can get the rotation period T of each circle. i，j，n , and finally calculate the blade speed

[0058] In the second step S200, according to the arrival time (t i，j，n ,t i+1，j，n ) and the installation angle interval Δθ of the sensor i，i+1 =θ i+1 -θ i Get blade tip vibration speed Wherein, R is the measured rotation radius from the rotor blade tip rotation axis to the blade tip;

[0059] In the second step S300 of the method, the vibration of the blade can generally be assumed to be the superposition of harmonic signals of different frequencies. Based on the blade tip vibration velocity signal, it can be expressed as The sparse representation model of under-sampled blade tip timing blade tip speed signal is constructed using sparse theory:

[0060]

[0061] in, is the average arrival time of the jth blade collected by the two adjacent sensors i and i+1 in the nth round, f Δl =f Δ1 *l is a fixed interval f Δ1 The l frequency component under can be used to estimate the blade vibration frequency; in addition, the sparse representation model of the blade tip vibration signal can be further expressed as v = Φ c , where Φ is the defined measurement matrix and c is the unknown coefficient vector;

[0062] The method is characterized in that in the second step S300, by solving the combinatorial optimization problem, a sparse solution can be obtained. The sparse vector c = [c1 c2 …c 2l-1 c 2l ] T ,like and The rth group is not zero, so the rth order vibration equation of the blade can be expressed as The resonant frequency of the blade is f r =f Δ1 *l;

[0063] In the second step S400 of the method, by locating the non-zero elements in the sparse representation of the blade tip timing blade tip speed signal, a blade tip speed forming design matrix H is constructed, and the least squares set is used to solve Based on the relationship between velocity and displacement, the vibration amplitude and phase of the blade are further obtained, where: It is represented by the vibration amplitude of the blade at the rth order identified by the blade tip speed and represents the vibration phase of the blade at the rth order;

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

[0065] 1. For multi-mode blade vibration, the number of sensors is 5, where the installation angle θ = [10° 25° 35° 45° 65°], such as Figure 4 shown.

[0066] 2. If the blade tip timing system is not equipped with a reference OPR sensor, the blade reference speed is estimated using the arrival time series measured by the blade tip timing sensor and the blade rotation angle. As shown in Figures 5(a) and 5(b), the fitting results are in good agreement with the measured data. As shown in Figures 6(a) and 6(b), the relative error is within 0.08%, and the root mean square error is 6.81×10 -9 , it can be seen that the rotation speed can be accurately estimated.

[0067] 3. Based on the estimated speed information, the blade tip vibration displacement is first calculated by using the time difference through the traditional blade tip timing as shown in Figure 7(a) and Figure 7(b); at the same time, the arrival time collected by two adjacent sensors (No. 1 and No. 2) and the installation angle Δθ between the sensors are used 12 =15°, the calculated blade tip vibration velocity is shown in Figure 7(b); when the blade rotates at 9600RPM, the blade resonates.

[0068] 4. Select the resonance area data of the peak value of the blade tip vibration response, and use the sparse theory to construct the sparseness of the under-sampled blade tip timing blade tip velocity signal based on the blade tip vibration displacement and velocity signal, and set the reconstruction sampling frequency to 4000Hz to realize the identification of the vibration frequency of the rotating blade. As shown in Figure 7(a) and Figure 7(b), the first-order modal spectrum based on the blade tip vibration displacement can only be identified at 482.2Hz, and the second-order modal frequency belongs to the intermediate frequency with lower energy. When the blade tip vibration displacement is measured, the measurement uncertainty increases due to the need to consider the influence of the reference speed multiple times, and it is difficult to accurately identify the multi-modal vibration parameters. On the contrary, the first-order modal frequency of the rotating blade identified based on the blade tip vibration velocity is 482.4Hz, the second-order modal frequency is 1932.6Hz, and the second-mode amplitude is enhanced.

[0069] According to another aspect of the present invention, the present disclosure also provides a system for a multi-mode blade tip timing measurement method based on blade tip speed, which comprises:

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

[0071] Blade reference speed calculation module: determines the actual operating speed of the rotor blade based on the arrival time and rotation angle fitting according to whether the blade tip timing measurement system is equipped with an OPR reference sensor;

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

[0073] Under-sampling signal processing module: used to establish a sparse representation model of the under-sampling blade tip vibration velocity signal, determine the multi-modal resonance frequency of the blade by sparse solution, and construct a design matrix based on the positioning of non-zero elements of the sparse solution, and identify the vibration amplitude and phase of the blade multi-mode by the least squares algorithm.

[0074] Furthermore, the system also includes a blade tip timing sensor layout optimization module, which determines the number of blade tip timing sensors and the circumferential installation positions of the blade tip timing sensors based on the vibration parameters. Further, the blade tip timing sensor layout optimization module determines the number N of circumferential blade tip timing sensor installations according to the multi-modal number M of the rotor blades. p .

[0075] Finally, it should be noted that the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making any creative work are within the scope of protection of the present application.

[0076] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A multi-modal blade tip timing measurement method based on blade tip speed, characterized in that: It includes the following steps: The first step S100: installing blade tip timing sensors in groups of two circumferentially on the rotor blade casing, obtaining a time sequence of a whole circle of rotor blades reaching the blade tip timing sensors, and obtaining a rotation speed of each circle based on the time sequence; The second step S200: obtaining the blade tip vibration speed according to the arrival time collected by two adjacent sensors, the installation angle of the blade tip timing sensor and the rotation speed; The third step S300: constructing a sparse representation model V of the undersampled blade tip timing velocity signal based on the blade tip vibration velocity, and obtaining a sparse solution to determine the blade multi-modal vibration frequency, wherein the sparse representation model is ,in, is the measurement matrix, is the unknown coefficient vector; Fourth step S400: constructing a design matrix using the positions of non-zero elements of the sparse solution, extracting elements of the measurement matrix to construct a vibration equation of the blade tip speed, and identifying the vibration amplitude of the multi-mode of the rotor blade via a least squares algorithm based on the design matrix and the vibration equation; In the first step S100, the relationship between the arrival time and the rotation angle position of the rotor blade is: ,in, For the The blade tip timing sensor measures the The angular position of the blade arrival time, the rotor blades have a total of leaves, is the number of blade tip timing sensors installed, For the The installation angle of the blade tip timing sensor, For the actual The rotation speed in the circle changes linearly, and the blade speed is: , the rotation angle of the rotor blade is expressed by a quadratic function fitting , after solving, we can get the rotation period of each circle , calculate the blade speed ,according to The blade tip timing sensor measures The actual arrival time of the blade , No. Base speed in the circle for: , of which the rotor blades have a total of blades, based on multimodal measurement installation The blade tip timing sensor collects continuous Circle data; In the second step S200, according to the blade tip timing sensor Arrival time of collection , adjacent blade tip timing sensor Arrival time of collection , Installation angle interval of blade tip timing sensor And the rotation speed to obtain the blade tip vibration speed ,in, It is the rotation radius from the rotor blade tip to the rotation axis of the blade tip.

2. The method according to claim 1, characterized in that In the first step S100, the number of circumferential blade tip timing sensors installed The number of multi-modes through the rotor blades Determine, among which, .

3. The method according to claim 1, characterized in that In the first step S100 , the installation angle interval between the blade tip timing sensors in a group of two is less than 10°.

4. The method according to claim 1, characterized in that: In the first step S100, an OPR speed sensor is installed to obtain the key phase signal. The key phase signal time series of the circle , based on the key phase signal time series, the rotor blade is calculated at the first Rotation speed .

5. The method according to claim 1, characterized in that In the third step S300, the blade tip vibration speed is , Expressed as The vibration coefficient of the blade tip vibration velocity is calculated by using the sparse theory to construct a sparse representation model of the under-sampled blade tip timing blade tip velocity signal: in, Based on and Two adjacent blade tip timing sensors are The first The average arrival time of blade number, For fixed interval Next frequency components to estimate the blade vibration frequency.

6. The method according to claim 5, characterized in that In the third step S300, by solving the combinatorial optimization problem sparse solution , where a greedy algorithm is used to approximate the sparse vector ,like and No. If the value of group is not zero, the rotor blade The vibration equation of order is expressed as , where the multimodal resonance frequency of the rotor blade is .

7. The method according to claim 6, characterized in that In the fourth step S400, a design matrix is ​​constructed by locating non-zero elements in the sparse representation model. , solved by the least squares algorithm , based on the relationship between velocity and displacement, the vibration amplitude and phase of the blade are obtained, where , It is represented by the blade tip speed identification of the first The vibration amplitude of the order and Indicates that the leaves are The vibration phase of the order.

8. A system for implementing a multi-mode blade tip timing measurement method based on blade tip speed according to any one of claims 1 to 7, characterized in that: These include, a blade tip arrival time measurement module configured to obtain a time sequence of a full revolution of rotor blades arriving at a blade tip timing sensor; A blade reference speed calculation module, which is connected to the blade tip arrival time measurement module, and the blade reference speed calculation module obtains the speed of each circle based on the time series; a blade tip vibration speed calculation module, which is connected to the blade tip arrival time measurement module and the blade tip arrival time measurement module, and the blade tip vibration speed calculation module obtains the blade tip vibration speed according to the arrival time collected by two adjacent sensors, the installation angle of the blade end timing sensor and the rotation speed; The under-sampling signal processing module is connected to the blade tip vibration velocity calculation module. The under-sampling signal processing module establishes a sparse representation model of the under-sampling blade tip vibration velocity, determines the multi-modal resonance frequency of the blade by sparse solution, and constructs a design matrix based on the positioning of non-zero elements of the sparse solution, and identifies the vibration amplitude and phase of the blade multi-mode by a least squares algorithm.

Images