Microwave Measurement Test System for Blade Vibration and Tip Clearance and Calibration Method

Abstract

The present invention provides a test system and a calibration method for measuring blade vibration and tip clearance by microwaves. The method includes: determining the signal trigger direction of each blade according to the microwave signals reflected by each blade; generating microwave amplitude trigger points according to the signal trigger directions of each blade, and performing trigger point screening on the microwave amplitude trigger points according to the signal trigger directions; determining the microwave amplitude deviation of the corresponding blade vibration according to each microwave amplitude trigger point, and determining the displacement value of the corresponding microwave amplitude trigger point according to the microwave amplitude deviation; determining the vibration amplitude of the blade according to the displacement values of each microwave amplitude trigger point, and obtaining the maximum microwave amplitude of each blade; matching the maximum microwave amplitude of each blade with a calibration table to obtain the target tip distance, and determining the tip clearance of each blade according to each target tip distance. The present invention can accurately calibrate the tip distance and vibration amplitude of the blade both when the engine rotates at a constant speed or a variable speed, improving the accuracy of calibrating the tip clearance and blade vibration parameters.

Description

Technical Field

[0001] The present invention relates to the technical field of parameter calibration, and particularly to a test system and calibration method for measuring blade vibration and tip clearance by microwave. Background Art

[0002] Tip clearance and blade vibration are key parameters for the healthy operation and energy consumption efficiency of an engine. Tip clearance refers to the tiny distance between the tip of an engine blade and its casing. Tip clearance and blade vibration are important parameters affecting the working efficiency and structural safety of the engine. Therefore, methods for measuring the parameters of tip clearance and blade vibration in an engine have received increasing attention.

[0003] In the prior art, the microwave ranging principle based on the phase method is used to measure tip clearance and blade vibration. During the parameter calibration process, when the phase of the blade undergoes a sudden jump, the calculated errors of tip clearance and blade vibration are relatively large, reducing the accuracy of parameter calibration for tip clearance and blade vibration. Summary of the Invention

[0004] The purpose of the embodiments of the present invention is to provide a test system and calibration method for measuring blade vibration and tip clearance by microwave, aiming to solve the problem of relatively low accuracy in parameter calibration of tip clearance and blade vibration during the existing parameter calibration generation process.

[0005] The embodiments of the present invention are implemented as follows. A test system and calibration method for measuring blade vibration and tip clearance by microwave, the method includes:

[0006] Receiving microwave signals reflected by each blade in the engine to be calibrated, and determining the signal trigger direction of each blade according to the microwave signals reflected by each blade;

[0007] Generating microwave amplitude trigger points according to the signal trigger direction of each blade, and performing trigger point screening on the microwave amplitude trigger points according to the signal trigger direction;

[0008] Determining the microwave amplitude deviation corresponding to the vibration of the corresponding blade according to each microwave amplitude trigger point after trigger point screening, and determining the displacement value of the corresponding microwave amplitude trigger point according to the microwave amplitude deviation;

[0009] Determining the vibration amplitude of the corresponding blade according to the displacement value of each microwave amplitude trigger point, and respectively obtaining the maximum microwave amplitude of each blade;

[0010] Matching the maximum microwave amplitude of each blade with a pre-stored calibration table to obtain the target tip distance, and determining the tip clearance of each blade according to each target tip distance.

[0011] Furthermore, before matching the maximum microwave amplitude of each blade with the pre-stored calibration table, it further includes:

[0012] Perform air response processing on each microwave probe, that is, collect signals when there is no object within 100 mm in front of the microwave probe, and obtain the system compensation values of the real and imaginary parts of each probe during air response;

[0013] Perform static calibration processing on blades of different thicknesses respectively, obtain the dynamic modulation signal diagram, and obtain the center coordinates in the dynamic modulation signal diagram to obtain the purified center coordinates. The dynamic modulation signal diagram is used to characterize the corresponding relationship between the modulation signal value and the measurement range;

[0014] Generate the calibration table according to the purified center coordinates and the system compensation values.

[0015] Furthermore, determining the system compensation values of the real and imaginary parts of each microwave probe according to the air response results includes:

[0016] Calculate the maximum deviation amounts of the real and imaginary parts of each microwave probe according to the air response results;

[0017] If the maximum deviation amounts of the real and imaginary parts of the microwave probe are less than the error threshold, determine the maximum deviation amounts of the real and imaginary parts of the microwave probe as the system compensation values.

[0018] Furthermore, generating the calibration table according to the purified center coordinates and the system compensation values includes:

[0019] Obtain the modulation signal values and the corresponding purified center coordinates corresponding to the blades of different thicknesses respectively;

[0020] For the blades of different thicknesses, calculate the corresponding modulation signal values, the corresponding purified center coordinates, and the corresponding system compensation values to obtain the phase change values, and generate the calibration table according to the corresponding relationship between the blades of different thicknesses and the phase change values.

[0021] Furthermore, determining the signal trigger direction of each blade according to the microwave signals reflected by each blade includes

[0022] Calculate the average value, maximum value, and minimum value of the microwave signals reflected by each blade respectively, and calculate the difference between the average value and the minimum value to obtain the first difference;

[0023] Calculate the difference between the maximum value and the minimum value to obtain the second difference, and calculate the product of the second difference and the threshold coefficient to obtain the deviation product value;

[0024] Calculate the difference between the first difference and the deviation product value to obtain the third difference, and calculate the difference between the maximum value and the average value to obtain the fourth difference;

[0025] If the third difference is less than the fourth difference, it is determined that the signal trigger direction of the blade is the rising edge;

[0026] If the third difference is greater than or equal to the fourth difference, it is determined that the signal trigger direction of the blade is the falling edge.

[0027] Furthermore, the screening of the microwave amplitude trigger points according to the signal trigger direction includes:

[0028] Determine the microwave amplitude trigger points with the signal trigger direction of the rising edge as signal mis-trigger points, and calculate the signal differences between the signal mis-trigger points and adjacent microwave amplitude trigger points respectively;

[0029] If any of the signal differences is greater than the signal threshold, delete the signal mis-trigger point.

[0030] Furthermore, the receiving of the microwave signals reflected by the blades in the engine to be calibrated includes:

[0031] Receive the microwave data reflected by the blades in the engine to be calibrated, and determine the microwave signals reflected by the blades as the signals with the signal waveform in the peak state in the microwave data.

[0032] Another object of the embodiment of the present invention is to provide a test system for measuring blade vibration and tip clearance by microwave, and the system includes:

[0033] A microwave signal receiving unit, configured to receive the microwave signals reflected by the blades in the engine to be calibrated, and determine the signal trigger direction of each blade according to the microwave signals reflected by each blade;

[0034] A trigger point screening unit, configured to generate microwave amplitude trigger points according to the signal trigger direction of each blade, and perform trigger point screening on the microwave amplitude trigger points according to the signal trigger direction;

[0035] A displacement value determination unit, configured to determine the microwave amplitude deviation of the corresponding blade vibration according to each microwave amplitude trigger point after trigger point screening, and determine the displacement value of the corresponding microwave amplitude trigger point according to the microwave amplitude deviation;

[0036] A vibration amplitude determination unit, configured to determine the vibration amplitude of the corresponding blade according to the displacement value of each microwave amplitude trigger point, and respectively obtain the maximum microwave amplitude of each blade;

[0037] A tip clearance determination unit, configured to match the maximum microwave amplitude of each blade with a pre-stored calibration table to obtain a target tip distance, and determine the tip clearance of each blade according to each target tip distance.

[0038] In the embodiment of the present invention, the signal trigger directions of the blades are determined by the microwave signals reflected by the blades. Based on the signal trigger directions, the trigger points of the microwave amplitude can be effectively screened, improving the accuracy of the microwave amplitude trigger points. After the trigger point screening, the microwave amplitude deviations corresponding to the vibrations of the blades can be effectively determined by the microwave amplitude deviations. The displacement values corresponding to the microwave amplitude trigger points can be effectively determined by the microwave amplitude deviations. Based on the displacement values of the microwave amplitude trigger points, the vibration amplitudes of the corresponding blades can be effectively determined. By obtaining the maximum microwave amplitudes of the blades and matching the maximum microwave amplitudes of the blades with the pre-stored calibration table, the target tip clearances of the blades can be effectively obtained. Based on the target tip clearances, the tip clearances of the blades can be effectively determined. The embodiment of the present invention can accurately calibrate the tip clearances and vibration amplitudes of the blades when the engine rotates at a constant speed or a variable speed (the phase of the blade undergoes a sudden jump), improving the accuracy of the calibration of the tip clearances and blade vibration parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a flowchart of a test method for measuring blade vibration and tip clearance by microwave provided in the first embodiment of the present invention;

[0040] Figure 2 is a schematic diagram of an indication sensor waveform provided in this embodiment;

[0041] Figure 3 is a schematic diagram of a microwave probe waveform provided in this embodiment;

[0042] Figure 4 is a schematic diagram of a dynamic diagram of a modulation signal in the calibration method provided in this embodiment;

[0043] Figure 5 is a flowchart of determining the signal trigger direction based on microwave signals provided in the second embodiment of the present invention;

[0044] Figure 6 is a schematic structural diagram of a test system for measuring blade vibration and tip clearance by microwave provided in the third embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0045] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0046] In order to illustrate the technical solutions described in the present invention, the following will be described through specific embodiments.

[0047] Example 1

[0048] Please refer to Figure 1, is a flowchart of a test method for measuring blade vibration and tip clearance by microwave provided in the first embodiment of the present invention. The test method includes the steps:

[0049] Step S10, receiving microwave signals reflected by each blade in the engine to be calibrated, and determining the signal trigger direction of each blade according to the microwave signals reflected by each blade;

[0050] Among them, a plurality of microwave probes are arranged on the casing of the engine to be calibrated. The number of the microwave probes can be set according to requirements. In this step, the number of the microwave probes is 4 or more. The microwave probes are used to transmit and receive microwave signals reflected by each blade in the engine. That is, in this step, based on the microwave probes receiving microwave signals reflected by each blade in the engine to be calibrated, an indication sensor is further arranged around the rotor of the engine. The indication sensor is used to collect the rotational speed signal of the engine;

[0051] Optionally, in this step, the receiving microwave signals reflected by each blade in the engine to be calibrated includes:

[0052] Receiving microwave data reflected by each blade in the engine to be calibrated, and determining the signals with the signal waveform in the peak state in the microwave data as the microwave signals reflected by each blade;

[0053] Among them, please refer to Figure 2 , a peak voltage will be generated on the signal waveform of the indication sensor. According to parameters such as the edge trigger type and the control rotational speed threshold, the trigger threshold can be automatically calculated and the trigger point sequence in the rotational speed sampling sequence can be found, so as to achieve the effect of real-time monitoring of the change of the engine rotational speed;

[0054] In this step, the blade and the blade root can be identified based on the amplitude change of the signal in the microwave data reflected by each blade. For example, please refer to Figure 3 , when the blade passes by the microwave probe, a peak will be formed on the signal waveform, which means that the energy is the largest when the blade passes by the microwave probe. The microwave amplitude signal much smaller than the peak value of the peak represents the energy change when the blade root passes by the microwave probe. Therefore, in this step, the signals with the signal waveform in the peak state in the microwave data are determined as the microwave signals reflected by each blade, thereby improving the accuracy of determining the microwave signals reflected by each blade.

[0055] Step S20, generating microwave amplitude trigger points according to the signal trigger direction of each blade, and performing trigger point screening on the microwave amplitude trigger points according to the signal trigger direction;

[0056] Among them, the trigger point screening of the microwave amplitude trigger points is performed through the signal trigger direction, which improves the accuracy of the microwave amplitude trigger points.

[0057] Step S30: Determine the microwave amplitude deviation corresponding to the vibration of each blade according to each microwave amplitude trigger point after trigger point screening, and determine the displacement value corresponding to the corresponding microwave amplitude trigger point according to the microwave amplitude deviation;

[0058] Among them, before calculating the vibration amplitude of the blade in real time, the phase relationship table between the microwave probe and the blade should be calculated according to the angle between each microwave probe and the starting point position of the rotor. The phase relationship table is used to confirm the position relationship between the microwave probe and the blade, and obtain the angle sequence of each blade for the calculation of the rotation speed trigger point. When calculating the vibration amplitude of the blade, the data of the first two cycles after spline interpolation should be removed first, that is, the data of the first two cycles in the rotation speed signal should be removed. Calculate the number of calculation times of the blade vibration per second according to the designed number of calculation cycles, and then calculate the microwave amplitude deviation caused by the blade vibration according to each microwave amplitude trigger point after trigger point screening, so as to calculate the displacement value corresponding to the microwave amplitude deviation;

[0059] Step S40: Determine the vibration amplitude of the corresponding blade according to the displacement value of each microwave amplitude trigger point, and respectively obtain the maximum microwave amplitude of each blade;

[0060] Among them, the displacement value of each microwave amplitude trigger point uses the unilateral amplitude minimum deviation estimation method to calculate the vibration amplitude corresponding to each blade;

[0061] Step S50: Match the maximum microwave amplitude of each blade with the pre-stored calibration table to obtain the target tip distance, and determine the tip clearance of each blade according to each target tip distance;

[0062] Among them, the calculation method of the tip clearance will calculate the tip distance between the microwave probe and the blade by referring to the calibration table with the phase corresponding to the maximum microwave amplitude found when each blade passes through the probe. Since the displacement value corresponding to each blade is calculated directly through the microwave amplitude deviation rather than through the phase deviation, and the tip clearance is calculated through the tip distance corresponding to the maximum microwave amplitude, the problems of phase jump and discontinuity during the variable speed process are solved; specifically, in this step, by matching the maximum microwave amplitude of the blade, that is, the energy signal, with the calibration table, the minimum distance on each blade, that is, the tip clearance, can be obtained. Calculating the tip clearance is also the application after calibration. The minimum value among the target tip distances corresponding to each blade is determined as the tip clearance of each blade;

[0063] Optionally, before the step of matching the maximum microwave amplitude of each blade with the pre-stored calibration table, it further includes:

[0064] Perform an empty response process on each microwave probe to obtain an empty response result, and determine the system compensation values of the real part and the imaginary part of each microwave probe according to the empty response result;

[0065] Among them, signal acquisition is carried out when there is no object within 100 mm in front of the microwave probe, and the system compensation values of the real part and the imaginary part of each probe are obtained for the response to the air. The system stability test of the microwave probe's response to the air is carried out. When the maximum deviation value of the system is of the order of 10 -5 magnitude, the system can be regarded as stable, and the system compensation values caused by factors such as circulator leakage in each channel can be obtained. Optionally, when there is no object within 100 mm in front of the microwave probe, the values of the real part I and the imaginary part Q of the probe at this time are collected, which is the compensation of the system;

[0066] In this step, during microwave signal processing, considering the influences such as circulator leakage and body noise of the system itself, the body noise of the signal instrument in the pure reflection response state is obtained. Therefore, a preprocessing function for microwave vibration phase is added to compensate the initial state of the system through the probe's response to the air. By obtaining the maximum deviation amounts of the real part and the imaginary part of each probe, the maximum center distance of the system at this time can be known. When the maximum center distance value of the system meets the probe control accuracy, that is, the error value is of the order of 10 -5 magnitude, the system can be regarded as stable, and at the same time, the system compensation values of the real part and the imaginary part of each probe can be obtained;

[0067] Specifically, in this step, the acquisition end chassis needs 0.5 - 1 h for warm-up before each power-on test, and the stability test module is used to evaluate the system stability. The control accuracy is set to 0.00001. When the accuracy of the maximum deviation value is E-5, the acquisition end system can be regarded as stable, and at the same time, the IQ stability compensation values of the four probes can be obtained.

[0068] Static calibration processing is carried out on blades with different thicknesses respectively to obtain the dynamic diagram of the modulation signal, and the center coordinates in the dynamic diagram of the modulation signal are obtained to obtain the purified center coordinates;

[0069] Among them, the dynamic diagram of the modulation signal is used to characterize the corresponding relationship between the modulation signal value and the measurement range. For example, please refer to Figure 4 ;

[0070] Generate the calibration table according to the purified center coordinates and the system compensation values;

[0071] Among them, based on the shape and thickness of the measured blade, calibration tests are carried out on each channel in turn and the purified center coordinates (center values) of each channel for the blade of this thickness are obtained. Then, the modulation signal values (IQ) obtained in the calibration tests of each channel are deducted from the system compensation values and the center values to obtain the calibration table at different tip distances;

[0072] When the system reaches stability, based on the attenuation characteristics of microwave signals varying with distance, tip distance calibration tests can be conducted on blades of different thicknesses. It is required that the calibration displacement step size increases and decreases at equal intervals. If they are not equal, an equally spaced sequence should be obtained by interpolation. And the calibration range should satisfy being greater than half of the microwave wavelength, which is 6.25 mm. The IQ signal values are a pair of quadrature modulated signals. In the polar coordinate system, the horizontal axis is I and the vertical axis is Q. During the calibration process, the changing trend of IQ values can be displayed point by point as the measurement range increases, such as Figure 4 shown. The IQ values show a spiral relationship as the measurement range increases. Then, the position of the center of the spiral is calculated, that is, the purified center coordinates required when calculating the calibration table. Refer to Figure 4 . The effect of the center value can be evaluated by calculating whether the distance radius r from each point within the half microwave wavelength range to the center value is greater than 6.25 mm, and whether the center position is within the spiral. After that, by subtracting the center value of each channel and the system compensation value, and ensuring that the phase difference between any two adjacent points satisfies between -180 degrees and 180 degrees, a calibration table with continuously changing phase with distance can be obtained;

[0073] In this step, the microwave amplitude measurement method is applied to the calibration test, the algorithms for calculating the center and the calibration table are optimized, and problems such as the difficult installation of the microwave probe caused by the polarization angle are solved; in the calibration test, the microwave phase and position relationship at each different tip distance point can be directly displayed through the spiral diagram relationship, and the effect of the center value of this channel can be evaluated by whether the center falls within the center of the spiral;

[0074] Furthermore, in this step, the system compensation values for the real and imaginary parts of each microwave probe determined according to the response result to the air include:

[0075] Calculating the maximum deviation of the real and imaginary parts of each microwave probe according to the response result to the air;

[0076] If the maximum deviation of the real and imaginary parts of the microwave probe is less than the error threshold, then the maximum deviation of the real and imaginary parts of the microwave probe is determined as the system compensation value;

[0077] Even further, in this step, the generation of the calibration table according to the purified center coordinates and the system compensation value includes:

[0078] Obtaining the modulation signal values corresponding to the blades of different thicknesses and the corresponding purified center coordinates respectively;

[0079] For the blades of different thicknesses, calculate the corresponding modulation signal values, the corresponding purified center coordinates, and the corresponding system compensation values to obtain the phase change values, and generate the calibration table according to the corresponding relationship between the blades of different thicknesses and the phase change values.

[0080] In this embodiment, the signal triggering directions of the respective blades are determined by the microwave signals reflected by the respective blades. Based on the signal triggering directions, the triggering points of the microwave amplitude can be effectively screened, improving the accuracy of the microwave amplitude triggering points. The microwave amplitude triggering points after the triggering point screening can effectively determine the microwave amplitude deviation corresponding to the vibration of the respective blades. Based on the microwave amplitude deviation, the displacement value corresponding to the microwave amplitude triggering point can be effectively determined. Based on the displacement values of the respective microwave amplitude triggering points, the vibration amplitude of the respective blades can be effectively determined. By obtaining the maximum microwave amplitude of each blade and matching the maximum microwave amplitude of each blade with a pre-stored calibration table, the target tip clearance of each blade can be effectively obtained. Based on the respective target tip clearances, the tip clearances of the respective blades can be effectively determined. The implementation of the present invention can accurately calibrate the tip clearance and vibration amplitude of the blades when the engine is at a constant speed or a variable speed, that is, when the phase of the blades undergoes a sudden jump, improving the accuracy of the calibration of the tip clearance and the blade vibration parameters.

[0081] Example 2

[0082] Please refer to Figure 5 , which is a flowchart for judging the signal triggering direction based on microwave signals provided by the second embodiment of the present invention. This embodiment is used to further refine the steps of step S10, including the steps:

[0083] Step S11, calculate the average value, maximum value, and minimum value of the microwave signals reflected by the respective blades, and calculate the difference between the average value and the minimum value to obtain a first difference;

[0084] Step S12, calculate the difference between the maximum value and the minimum value to obtain a second difference, and calculate the product of the second difference and a threshold coefficient to obtain a deviation product value;

[0085] Step S13, calculate the difference between the first difference and the deviation product value to obtain a third difference, and calculate the difference between the maximum value and the average value to obtain a fourth difference;

[0086] Step S14, if the third difference is less than the fourth difference, it is determined that the signal triggering direction of the blade is the rising edge;

[0087] Step S15, if the third difference is greater than or equal to the fourth difference, it is determined that the signal triggering direction of the blade is the falling edge;

[0088] Among them, first calculate the average value, maximum value, and minimum value in the microwave signals reflected by each blade, and then calculate the value obtained by subtracting the minimum value from the average value and then subtracting the product of the threshold coefficient and the deviation between the maximum value and the minimum value. If this calculated value is less than the deviation between the maximum value and the average value, the trigger direction is the rising edge, and the signal is abnormal, mainly caused by compensation calculation; otherwise, the signal is normal, and the trigger direction is the falling edge;

[0089] Optionally, in this embodiment, for step S20, the screening of the trigger points of the microwave amplitude according to the signal trigger direction includes:

[0090] Determine the microwave amplitude trigger points with the rising edge of the signal trigger direction as signal mis-trigger points, and calculate the signal differences between the signal mis-trigger points and adjacent microwave amplitude trigger points respectively;

[0091] If any of the signal differences is greater than the signal threshold, delete the signal mis-trigger point;

[0092] Among them, the trigger points of the microwave signal waveforms reflected by each blade should be unified. If there are mis-trigger points, it will affect the vibration of the blade and the calculation of the tip clearance. Therefore, in the process of trigger point selection and evaluation, it should be ensured that the first trigger point conforms to the trigger direction of this section of data and is accurate. Then, judge whether the abnormal trigger point meets the size comparison with adjacent points. If the condition is not met, delete the mis-trigger point.

[0093] In this embodiment, by comparing the third difference value with the fourth difference value numerically to determine the signal trigger direction of each blade, that is, if the third difference value is less than the fourth difference value, it is determined that the signal trigger direction of the blade is the rising edge; if the third difference value is greater than or equal to the fourth difference value, it is determined that the signal trigger direction of the blade is the falling edge. By calculating the signal differences between the signal mis-trigger points and adjacent microwave amplitude trigger points respectively, it can effectively judge whether each mis-trigger point needs to be deleted, improve the accuracy of the microwave amplitude trigger points, and ensure the unity between the trigger points of the microwave signal waveforms reflected by the blades.

[0094] Example 3

[0095] Please refer to Figure 6 , which is a schematic structural diagram of a test system 100 for measuring blade vibration and tip clearance by microwave provided in the third embodiment of the present invention, including: a microwave signal receiving unit 10, a trigger point screening unit 11, a displacement value determination unit 12, a vibration amplitude determination unit 13, and a tip clearance determination unit 14, where:

[0096] The microwave signal receiving unit 10 is configured to receive the microwave signals reflected by each blade in the engine to be calibrated, and determine the signal trigger direction of each blade according to the microwave signals reflected by each blade.

[0097] Among them, the microwave signal receiving unit 10 is further configured to: calculate the average value, maximum value, and minimum value of the microwave signals reflected by each blade respectively, and calculate the difference between the average value and the minimum value to obtain a first difference;

[0098] calculate the difference between the maximum value and the minimum value to obtain a second difference, and calculate the product of the second difference and a threshold coefficient to obtain a deviation product value;

[0099] calculate the difference between the first difference and the deviation product value to obtain a third difference, and calculate the difference between the maximum value and the average value to obtain a fourth difference;

[0100] if the third difference is less than the fourth difference, it is determined that the signal trigger direction of the blade is the rising edge;

[0101] if the third difference is greater than or equal to the fourth difference, it is determined that the signal trigger direction of the blade is the falling edge.

[0102] Furthermore, the microwave signal receiving unit 10 is further configured to: receive the microwave data reflected by each blade in the engine to be calibrated, and determine the microwave signals reflected by each blade from the signals in the microwave data whose signal waveforms are in the peak state.

[0103] The trigger point screening unit 11 is configured to generate microwave amplitude trigger points according to the signal trigger directions of each blade, and perform trigger point screening on the microwave amplitude trigger points according to the signal trigger directions.

[0104] Among them, the trigger point screening unit 11 is further configured to: determine the microwave amplitude trigger points with the signal trigger direction of the rising edge as signal mis-trigger points, and calculate the signal differences between the signal mis-trigger points and adjacent microwave amplitude trigger points respectively;

[0105] if any of the signal differences is greater than a signal threshold, the signal mis-trigger point is deleted.

[0106] The displacement value determination unit 12 is configured to determine the microwave amplitude deviation of the corresponding blade vibration according to each microwave amplitude trigger point after trigger point screening, and determine the displacement value of the corresponding microwave amplitude trigger point according to the microwave amplitude deviation.

[0107] The vibration amplitude determination unit 13 is configured to determine the vibration amplitude of the corresponding blade according to the displacement values of each microwave amplitude trigger point, and respectively obtain the maximum microwave amplitudes of each blade.

[0108] The tip clearance determination unit 14 is configured to match the maximum microwave amplitudes of each blade with a pre-stored calibration table to obtain a target tip distance, and determine the tip clearance of each blade according to each target tip distance.

[0109] Among them, the tip clearance determination unit 14 is further configured to: perform air response processing on each microwave probe to obtain an air response result, and determine the system compensation values of the real part and the imaginary part of each microwave probe according to the air response result;

[0110] Perform static calibration processing on blades with different thicknesses respectively to obtain a modulation signal dynamic diagram, and obtain the center coordinates in the modulation signal dynamic diagram to obtain purified center coordinates, where the modulation signal dynamic diagram is used to characterize the correspondence between the modulation signal value and the measurement range;

[0111] Generate the calibration table according to the purified center coordinates and the system compensation values.

[0112] Optionally, the tip clearance determination unit 14 is further configured to: calculate the maximum deviation amounts of the real part and the imaginary part of each microwave probe according to the air response result;

[0113] If the maximum deviation amounts of the real part and the imaginary part of the microwave probe are less than the error threshold, then determine the maximum deviation amounts of the real part and the imaginary part of the microwave probe as the system compensation values.

[0114] Furthermore, the tip clearance determination unit 14 is further configured to: respectively obtain the modulation signal values and the corresponding purified center coordinates corresponding to the blades with different thicknesses;

[0115] For the blades with different thicknesses, calculate the corresponding modulation signal values, the corresponding purified center coordinates, and the corresponding system compensation values to obtain phase change values, and generate the calibration table according to the correspondence between the blades with different thicknesses and the phase change values.

[0116] In this embodiment, the signal trigger directions of the blades are determined by the microwave signals reflected by the blades. Based on the signal trigger directions, the trigger points of the microwave amplitude can be effectively screened, improving the accuracy of the trigger points of the microwave amplitude. After the trigger point screening, the microwave amplitude deviations corresponding to the vibrations of the blades can be effectively determined. Through the microwave amplitude deviations, the displacement values corresponding to the trigger points of the microwave amplitude can be effectively determined. Based on the displacement values of the trigger points of the microwave amplitude, the vibration amplitudes of the corresponding blades can be effectively determined. By obtaining the maximum microwave amplitudes of the blades and matching the maximum microwave amplitudes of the blades with the pre-stored calibration table, the target tip distances of the blades can be effectively obtained. Based on the target tip distances, the tip clearances of the blades can be effectively determined. The implementation of the present invention can accurately calibrate the tip distances and vibration amplitudes of the blades when the engine rotates at a constant speed or a variable speed, that is, when the phase of the blades undergoes a sudden jump, improving the accuracy of the calibration of the tip clearances and the vibration parameters of the blades.

[0117] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A test method for measuring blade vibration and tip clearance by microwave, characterized in that The method includes: Receiving microwave signals reflected by each blade in the engine to be calibrated, and determining the signal trigger direction of each blade according to the microwave signals reflected by each blade; Generating microwave amplitude trigger points according to the signal trigger directions of each blade, and performing trigger point screening on the microwave amplitude trigger points according to the signal trigger directions; Determining the microwave amplitude deviation corresponding to the vibration of the corresponding blade according to each microwave amplitude trigger point after trigger point screening, and determining the displacement value of the corresponding microwave amplitude trigger point according to the microwave amplitude deviation; Determining the vibration amplitude of the corresponding blade according to the displacement values of each microwave amplitude trigger point, and respectively obtaining the maximum microwave amplitude of each blade; Matching the maximum microwave amplitude of each blade with a pre-stored calibration table to obtain a target tip distance, and determining the tip clearance of each blade according to each target tip distance.

2. The test method for measuring blade vibration and tip clearance by microwave according to claim 1, wherein Before matching the maximum microwave amplitude of each blade with the pre-stored calibration table, it further includes: Performing an air response process on each microwave probe to obtain an air response result, and determining the system compensation values of the real part and the imaginary part of each microwave probe according to the air response result; Performing static calibration processing on blades with different thicknesses respectively to obtain a modulation signal dynamic diagram, and obtaining the center coordinates in the modulation signal dynamic diagram to obtain purified center coordinates, where the modulation signal dynamic diagram is used to characterize the corresponding relationship between the modulation signal value and the measurement range; Generating the calibration table according to the purified center coordinates and the system compensation values.

3. The test method for measuring blade vibration and tip clearance by microwave as described in claim 2, characterized in that, The determining the system compensation values of the real part and the imaginary part of each microwave probe according to the air response result includes: Calculating the maximum deviation amounts of the real part and the imaginary part of each microwave probe according to the air response result; If the maximum deviation amounts of the real part and the imaginary part of the microwave probe are less than the error threshold, determining the maximum deviation amounts of the real part and the imaginary part of the microwave probe as the system compensation values.

4. The test method for measuring blade vibration and tip clearance by microwave as claimed in claim 2, wherein, The generating the calibration table according to the purified center coordinates and the system compensation values includes: Respectively obtaining the modulation signal values corresponding to the blades with different thicknesses and the corresponding purified center coordinates; For the blades with different thicknesses, calculating the corresponding modulation signal values, the corresponding purified center coordinates, and the corresponding system compensation values to obtain a phase change value, and generating the calibration table according to the corresponding relationship between the blades with different thicknesses and the phase change value.

5. The test method for measuring blade vibration and tip clearance by microwave as described in claim 1, wherein, The determining the signal trigger direction of each blade according to the microwave signals reflected by each blade includes Respectively calculating the average value, the maximum value, and the minimum value of the microwave signals reflected by each blade, and calculating the difference between the average value and the minimum value to obtain a first difference; Calculating the difference between the maximum value and the minimum value to obtain a second difference, and calculating the product of the second difference and the threshold coefficient to obtain a deviation product value; Calculating the difference between the first difference and the deviation product value to obtain a third difference, and calculating the difference between the maximum value and the average value to obtain a fourth difference; If the third difference is less than the fourth difference, determining that the signal trigger direction of the blade is the rising edge; If the third difference is greater than or equal to the fourth difference, determining that the signal trigger direction of the blade is the falling edge.

6. The test method for measuring blade vibration and tip clearance by microwave as described in claim 5, wherein The triggering point screening of the microwave amplitude triggering point according to the signal triggering direction includes: Determining the microwave amplitude triggering points with the rising edge of the signal triggering direction as signal mis-triggering points, and respectively calculating the signal differences between the signal mis-triggering points and adjacent microwave amplitude triggering points; If any of the signal differences is greater than the signal threshold, deleting the signal mis-triggering points.

7. The test method for measuring blade vibration and tip clearance by microwave according to any one of claims 1 to 6, characterized in that, The receiving of the microwave signals reflected by the blades in the engine to be calibrated includes: Receiving the microwave data reflected by the blades in the engine to be calibrated, and determining the signals with the signal waveforms in the wave peak state in the microwave data as the microwave signals reflected by the blades.

8. A test system for measuring blade vibration and tip clearance by microwave, characterized in that, The system includes: A microwave signal receiving unit, configured to receive the microwave signals reflected by the blades in the engine to be calibrated, and determine the signal triggering directions of the blades according to the microwave signals reflected by the blades; A triggering point screening unit, configured to generate microwave amplitude triggering points according to the signal triggering directions of the blades, and perform triggering point screening on the microwave amplitude triggering points according to the signal triggering direction; A displacement value determining unit, configured to determine the microwave amplitude deviation of the corresponding blade vibration according to the microwave amplitude triggering points after triggering point screening, and determine the displacement value of the corresponding microwave amplitude triggering point according to the microwave amplitude deviation; A vibration amplitude determining unit, configured to determine the vibration amplitude of the corresponding blade according to the displacement values of the microwave amplitude triggering points, and respectively obtain the maximum microwave amplitudes of the blades; A tip clearance determining unit, configured to match the maximum microwave amplitudes of the blades with a pre-stored calibration table to obtain the target tip distances, and determine the tip clearances of the blades according to the target tip distances.

9. The test system for measuring blade vibration and tip clearance by microwave as claimed in claim 8, wherein The tip clearance determining unit is further configured to: Perform an air response process on each microwave probe to obtain an air response result, and determine the system compensation values of the real part and the imaginary part of each microwave probe according to the air response result; Perform static calibration processing on blades with different thicknesses respectively to obtain a modulation signal dynamic diagram, and obtain the center coordinates in the modulation signal dynamic diagram to obtain purified center coordinates, where the modulation signal dynamic diagram is used to characterize the corresponding relationship between the modulation signal value and the measurement range; Generate the calibration table according to the purified center coordinates and the system compensation values.

10. The test system for measuring blade vibration and tip clearance by microwave as described in claim 9, characterized in that, The tip clearance determining unit is further configured to: Calculate the maximum deviation amounts of the real part and the imaginary part of each microwave probe according to the air response result; If the maximum deviation amounts of the real part and the imaginary part of the microwave probe are less than the error threshold, determining the maximum deviation amounts of the real part and the imaginary part of the microwave probe as the system compensation values.

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