CN115452387A - Testing system for measuring blade vibration and blade tip clearance by microwave and calibration method - Google Patents

Testing system for measuring blade vibration and blade tip clearance by microwave and calibration method Download PDF

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Publication number
CN115452387A
CN115452387A CN202211199747.5A CN202211199747A CN115452387A CN 115452387 A CN115452387 A CN 115452387A CN 202211199747 A CN202211199747 A CN 202211199747A CN 115452387 A CN115452387 A CN 115452387A
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China
Prior art keywords
blade
microwave
signal
value
amplitude
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Inventor
刘汉钊
朱超
柯银鸿
郎根峰
许静玲
翁新全
刘瑞林
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Xiamen Niell Electronics Co ltd
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Xiamen Niell Electronics Co ltd
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Priority to CN202211199747.5A priority Critical patent/CN115452387A/en
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M15/00—Testing of engines
    • G01M15/02—Details or accessories of testing apparatus
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B15/00—Measuring arrangements characterised by the use of electromagnetic waves or particle radiation, e.g. by the use of microwaves, X-rays, gamma rays or electrons
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D21/00—Measuring or testing not otherwise provided for
    • G01D21/02—Measuring two or more variables by means not covered by a single other subclass
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
    • G01H17/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves, not provided for in the preceding groups

Abstract

The invention provides a test system and a calibration method for measuring blade vibration and blade tip clearance by microwave, wherein the method comprises the following steps: determining the signal triggering direction of each blade according to the microwave signal reflected by each blade; generating microwave amplitude trigger points according to the signal trigger direction of each blade, and screening the microwave amplitude trigger points according to the signal trigger direction; determining microwave amplitude deviation corresponding to blade vibration according to each microwave amplitude trigger point, and determining a displacement value corresponding to the microwave amplitude trigger point according to the microwave amplitude deviation; determining the vibration amplitude of the blade according to the displacement value of each microwave amplitude trigger point, and acquiring the maximum microwave amplitude of each blade; and matching the maximum microwave amplitude of each blade with the calibration table to obtain a target blade tip distance, and determining the blade tip clearance of each blade according to each target blade tip distance. The method can accurately calibrate the blade tip distance and the vibration amplitude of the blade when the engine is in constant rotating speed or variable rotating speed, and improves the accuracy of blade tip clearance and blade vibration parameter calibration.

Description

Testing system for measuring blade vibration and blade tip clearance by microwave and calibration method
Technical Field
The invention relates to the technical field of parameter calibration, in particular to a test system and a calibration method for measuring blade vibration and blade tip clearance by microwaves.
Background
Blade tip clearance and blade vibration are key parameters for engine healthy operation and energy efficiency. The tip clearance refers to a small distance between the tip of the engine and a casing of the engine, and the tip clearance and the blade vibration are important parameters influencing the working benefit and the structural safety of the engine, so that a parameter measurement method for the tip clearance and the blade vibration in the engine is more and more emphasized by people.
In the prior art, the blade tip clearance and the blade vibration are measured based on a phase method by using a microwave distance measuring principle, and in the parameter calibration process, when the phase of the blade jumps suddenly, the blade tip clearance and the blade vibration error obtained through calculation are large, so that the accuracy of the calibration of the blade tip clearance and the blade vibration parameters is reduced.
Disclosure of Invention
The embodiment of the invention aims to provide a testing system and a calibration method for measuring blade vibration and blade tip clearance by microwaves, and aims to solve the problem that the blade tip clearance and blade vibration parameter calibration accuracy is low in the existing parameter calibration generation process.
The embodiment of the invention is realized in such a way that a test system and a calibration method for measuring blade vibration and blade tip clearance by microwave comprise the following steps:
receiving microwave signals reflected by each blade in the engine to be calibrated, and determining the signal triggering direction of each blade according to the microwave signals reflected by each blade;
generating microwave amplitude trigger points according to the signal trigger direction of each blade, and screening the microwave amplitude trigger points according to the signal trigger direction;
determining microwave amplitude deviation corresponding to blade vibration according to each microwave amplitude trigger point after the trigger point screening, and determining a displacement value corresponding to the microwave amplitude trigger point according to the microwave amplitude deviation;
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;
and matching the maximum microwave amplitude of each blade with a pre-stored calibration table to obtain a target blade tip distance, and determining the blade tip clearance of each blade according to each target blade tip distance.
Further, before the matching the maximum microwave amplitude of each blade with the pre-stored calibration table, the method further includes:
carrying out the null response processing on each microwave probe, namely carrying out signal acquisition when no object exists within 100mm in front of the microwave probe to obtain the system compensation values of the real part and the imaginary part of each probe in the null response;
respectively carrying out static calibration processing on blades with different thicknesses to obtain a modulation signal dynamic graph, and obtaining circle center coordinates in the modulation signal dynamic graph to obtain purified circle center coordinates, wherein the modulation signal dynamic graph is used for representing the corresponding relation between a modulation signal value and a measurement range;
and generating the calibration table according to the purified circle center coordinates and the parameter compensation values.
Furthermore, the determining the system compensation value of the real part and the imaginary part of each microwave probe according to the null response result comprises:
calculating the maximum deviation amount of the real part and the imaginary part of each microwave probe according to the null response result;
and if the maximum deviation amount of the real part and the imaginary part of the microwave probe is smaller than an error threshold, determining the maximum deviation amount of the real part and the imaginary part of the microwave probe as the system compensation value.
Further, the generating the calibration table according to the coordinates of the refined circle center and the parameter compensation value includes:
respectively obtaining modulation signal values corresponding to the blades with different thicknesses and corresponding purified circle center coordinates;
and calculating a corresponding modulation signal value, a corresponding purification circle center coordinate and a corresponding system compensation value aiming at the blades with different thicknesses to obtain a phase change value, and generating the calibration table according to the corresponding relation between the blades with different thicknesses and the phase change value.
Further, the method for determining the signal triggering direction of each blade according to the microwave signal reflected by each blade comprises
Respectively calculating the average value, the maximum value and the minimum value of the microwave signals reflected by each blade, and calculating the difference value between the average value and the minimum value to obtain a first difference value;
calculating a difference value between the maximum value and the minimum value to obtain a second difference value, and calculating a product between the second difference value and a threshold coefficient to obtain a deviation product value;
calculating a difference between the first difference and the deviation product value to obtain a third difference, and calculating a difference between the maximum value and the average value to obtain a fourth difference;
if the third difference is smaller than the fourth difference, determining that the signal triggering direction of the blade is a rising edge;
and if the third difference is larger than or equal to the fourth difference, determining that the signal triggering direction of the blade is a falling edge.
Further, the performing trigger point screening on the microwave amplitude trigger point according to the signal trigger direction includes:
determining the microwave amplitude trigger point with the signal trigger direction as a rising edge as a signal false trigger point, and respectively calculating a signal difference value between the signal false trigger point and an adjacent microwave amplitude trigger point;
and if any signal difference value is larger than a signal threshold value, deleting the signal false trigger point.
Further, the receiving of the microwave signal reflected by each blade in the engine to be calibrated includes:
and receiving microwave data reflected by each blade in the engine to be calibrated, and determining the signal waveform in the microwave data as a signal in a wave crest state as a microwave signal reflected by each blade.
Another object of an embodiment of the present invention is to provide a testing system for measuring blade vibration and blade tip clearance by microwave, wherein the system includes:
the microwave signal receiving unit is used for receiving microwave signals reflected by each blade in the engine to be calibrated and determining the signal triggering direction of each blade according to the microwave signals reflected by each blade;
the trigger point screening unit is used for generating microwave amplitude trigger points according to the signal trigger direction of each blade and screening the trigger points of the microwave amplitude trigger points according to the signal trigger direction;
the displacement value determining unit is used for determining microwave amplitude deviation corresponding to blade vibration according to each microwave amplitude trigger point after the trigger points are screened, and determining a displacement value corresponding to the microwave amplitude trigger point according to the microwave amplitude deviation;
the vibration amplitude determining unit is used for 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;
and the blade tip clearance determining unit is used for matching the maximum microwave amplitude of each blade with a pre-stored calibration table to obtain a target blade tip distance, and determining the blade tip clearance of each blade according to each target blade tip distance.
According to the embodiment of the invention, the signal trigger direction of each blade is determined through the microwave signal reflected by each blade, the trigger point screening can be effectively carried out on the microwave amplitude trigger point based on the signal trigger direction, the accuracy of the microwave amplitude trigger point is improved, the microwave amplitude deviation of the vibration of each blade can be effectively determined through each microwave amplitude trigger point after the trigger point screening is carried out, the displacement value of the corresponding microwave amplitude trigger point can be effectively determined through the microwave amplitude deviation, the vibration amplitude of each blade can be effectively determined based on the displacement value of each microwave amplitude trigger point, the maximum microwave amplitude of each blade is matched with a pre-stored calibration table by obtaining the maximum microwave amplitude of each blade, the target blade tip distance of each blade can be effectively obtained, and the blade tip clearance and the vibration amplitude of each blade can be effectively determined based on each target blade tip distance.
Drawings
FIG. 1 is a flow chart of a testing method for measuring blade vibration and blade tip clearance by microwave according to a first embodiment of the present invention;
FIG. 2 is a schematic diagram of a waveform of an indicating sensor provided in the present embodiment;
FIG. 3 is a schematic diagram of a waveform of a microwave probe provided in the present embodiment;
FIG. 4 is a schematic diagram of a dynamic diagram of a modulation signal in the calibration method provided in this embodiment;
FIG. 5 is a flowchart of determining a triggering direction of a signal based on a microwave signal according to a second embodiment of the present invention;
fig. 6 is a schematic structural diagram of a testing system for measuring blade vibration and blade tip clearance by microwave according to a third embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the invention.
In order to explain the technical means of the present invention, the following description will be given by way of specific examples.
Example one
Referring to fig. 1, it is a flowchart of a testing method for measuring blade vibration and blade tip clearance by microwave according to a first embodiment of the present invention, the testing method includes the steps of:
step S10, receiving microwave signals reflected by each blade in the engine to be calibrated, and determining the signal triggering direction of each blade according to the microwave signals reflected by each blade;
the method comprises the following steps that a plurality of microwave probes are arranged on a casing of the engine to be calibrated, the number of the microwave probes can be set according to requirements, in the step, the number of the microwave probes is 4 or more than 4, the microwave probes are used for transmitting and receiving microwave signals reflected by blades in the engine, namely, in the step, the microwave probes are used for receiving the microwave signals reflected by the blades in the engine to be calibrated, indication sensors are further arranged around a rotor of the engine, and the indication sensors are used for collecting rotating speed signals of the engine;
optionally, in this step, the receiving a microwave signal reflected by each blade in the engine to be calibrated includes:
receiving microwave data reflected by each blade in the engine to be calibrated, and determining a signal waveform in the microwave data as a signal in a wave crest state as a microwave signal reflected by each blade;
referring to fig. 2, a peak voltage is generated on a signal waveform of the indication sensor, and according to parameters such as an edge trigger type and a control rotation speed threshold, a trigger threshold can be automatically calculated and a trigger point row in a rotation speed sampling sequence can be searched, so that the effect of monitoring the change of the rotation speed of the engine in real time is achieved;
in this step, the blade and the blade root may be identified based on the amplitude change of the signal in the microwave data reflected by each blade, for example, referring to fig. 3, when the blade passes through the microwave probe, a peak may be formed on the waveform of the signal, that is, it represents that the energy of the blade passing through the microwave probe is the largest, and the microwave amplitude signal far smaller than the peak represents the energy change of the blade root passing through the microwave probe.
Step S20, generating microwave amplitude trigger points according to the signal trigger direction of each blade, and screening the microwave amplitude trigger points according to the signal trigger direction;
the method and the device have the advantages that the trigger points are screened according to the signal trigger direction, so that the accuracy of the microwave amplitude trigger points is improved.
Step S30, determining microwave amplitude deviation corresponding to blade vibration according to each microwave amplitude trigger point after the trigger point screening, and determining a displacement value corresponding to the microwave amplitude trigger point according to the microwave amplitude deviation;
before calculating the vibration amplitude of the blade in real time, a phase relation table between the microwave probe and the blade is calculated according to an included angle between each microwave probe and the initial point position of the rotor, wherein the phase relation table is used for confirming the position relation between the microwave probe and the blade to obtain an angle sequence of each blade for calculating a rotating speed trigger point. When the vibration amplitude of the blade is calculated, data of two successive periods of spline interpolation are distributed and removed firstly, namely front and back 2 periods of data in a rotating speed signal are removed, the calculation times of blade vibration per second are calculated according to the set calculation times, and then microwave amplitude deviation generated due to blade vibration is calculated according to each microwave amplitude trigger point after the trigger point screening, so that a displacement value corresponding to the microwave amplitude deviation is calculated;
step S40, 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;
calculating the vibration amplitude corresponding to each blade by adopting a unilateral amplitude minimum deviation estimation method for the displacement value of each microwave amplitude trigger point;
step S50, matching the maximum microwave amplitude of each blade with a pre-stored calibration table to obtain a target blade tip distance, and determining the blade tip clearance of each blade according to each target blade tip distance;
the blade tip clearance calculation method calculates the blade tip distance between the microwave probe and the blades by referring to a calibration table through the phase corresponding to the maximum microwave amplitude value found when each blade passes through the probe, calculates the displacement value corresponding to each blade directly through the microwave amplitude value deviation instead of the phase deviation, and calculates the blade tip clearance through the blade tip distance corresponding to the maximum microwave amplitude value, thereby solving the problems of discontinuous jump and mutation of the phase and the like in the process of variable rotating speed; specifically, in the step, the maximum microwave amplitude, i.e., the energy signal, of the blade is matched with a calibration table, so that the minimum distance on each blade, i.e., the tip clearance of the blade tip can be obtained, the calculation of the tip clearance of the blade tip is also the application after the calibration is completed, and the minimum value in the target tip distance corresponding to each blade is determined as the tip clearance of each blade tip;
optionally, in this step, before the step of matching the maximum microwave amplitude of each blade with a pre-stored calibration table, the method further includes:
carrying out null response processing on each microwave probe to obtain a null response result, and determining system compensation values of a real part and an imaginary part of each microwave probe according to the null response result;
acquiring signals when no object exists within 100mm in front of the microwave probe, obtaining system compensation values of a real part and an imaginary part of each probe in response to air, testing the system stability of the response to air of the microwave probe, and testing the system stability when the maximum deviation value of the system is 10 -5 The system can be regarded as stable during magnitude order, namely a system compensation value caused by factors such as circulator leakage of each channel can be obtained, optionally, when no object exists in the range of 100mm in front of the microwave probe, the values of a real part I and an imaginary part Q of the probe at the moment are collected, namely the compensation of the system;
in the step, when microwave signal processing is carried out, the body noise of the signal instrument in a pure reflection response state is further obtained by considering the influences of circulator leakage, body noise of a device body and the like of the system, so that a preprocessing function of a microwave vibration phase is added, and the probe is used for compensating the initial state of the system through the empty response. The maximum central distance of the system can be obtained by obtaining the maximum deviation of the real part and the imaginary part of each probe, and when the maximum central distance value of the system meets the control precision of the probe, namely the error value is 10 -5 In order of magnitude, the system can be regarded as stable, and the system compensation values of the real part and the imaginary part of each probe can be obtained;
specifically, in the step, the acquisition-side chassis needs 0.5-1h of time for warming before each boot test, and the stability test module is used for evaluating the stability of the system. The control precision is set to be 0.00001, when the precision of the maximum deviation value is E-5, the acquisition end system can be considered to be stable, and IQ stability compensation values of the four probes can be obtained simultaneously.
Respectively carrying out static calibration processing on blades with different thicknesses to obtain a modulation signal dynamic graph, and obtaining circle center coordinates in the modulation signal dynamic graph to obtain purified circle center coordinates;
the dynamic diagram of the modulation signal is used to represent the corresponding relationship between the modulation signal value and the measurement range, for example, please refer to fig. 4;
generating the calibration table according to the purified circle center coordinates and the parameter compensation values;
sequentially carrying out calibration tests on each channel based on the shape and thickness of the blade to be measured, obtaining a purified circle center coordinate (circle center value) of each channel for the blade with the thickness, and subtracting a system compensation value and a circle center value from a modulation signal value (IQ) value obtained in each channel calibration test to obtain a calibration table under different blade tip distances;
when the system is stable, blade tip distance calibration tests can be carried out on blades with different thicknesses based on the attenuation characteristic that microwave signals change along with distance, wherein the calibration displacement step length is required to be increased or decreased at equal intervals, if the calibration displacement step length is unequal, an equal interval sequence is obtained according to interpolation, the calibration range meets the condition that the microwave wavelength is more than one half and 6.25mm, the IQ signal value is a pair of modulation signals with orthogonal phases, and in a polar coordinate system, the horizontal axis is I and the vertical axis is Q. In the calibration process, the variation trend of the IQ value can be displayed point by point along with the increase of the measurement range, as shown in fig. 4, the IQ value presents a spiral coil relationship along with the increase of the measurement range. And then calculating the circle center position of the spiral coil, namely calculating the coordinates of the purified circle center required by the calibration table. Referring to fig. 4, the effect of the center value can be evaluated by calculating whether the distance radius r from each point in the half microwave wavelength range to the center value is greater than 6.25mm and whether the center position is located in the spiral coil, and then a calibration table with continuously changing phase along with the distance change can be obtained by deducting the center value of each channel and the system compensation value and randomly satisfying the phase difference between-180 degrees and 180 degrees between the front and the back adjacent phase differences;
in the step, a microwave amplitude measuring method is applied to a calibration test, the calculation of the circle center and the calibration table algorithm are optimized, and the problems that a microwave probe is not easy to mount due to the polarization angle and the like are solved; in the calibration test, the microwave phase and position relation of different blade tip distance points can be directly displayed through the relationship of a spiral graph, and the effect of the circle center value of the channel is evaluated through whether the circle center falls into the circle center of the spiral circle or not;
further, in this step, the determining the system compensation value of the real part and the imaginary part of each microwave probe according to the null response result includes:
calculating the maximum deviation amount of the real part and the imaginary part of each microwave probe according to the null response result;
if the maximum deviation amount of the real part and the imaginary part of the microwave probe is smaller than an error threshold, determining the maximum deviation amount of the real part and the imaginary part of the microwave probe as the system compensation value;
further, in this step, the generating the calibration table according to the refined circle center coordinates and the parameter compensation value includes:
respectively obtaining modulation signal values corresponding to the blades with different thicknesses and corresponding purified circle center coordinates;
and calculating a corresponding modulation signal value, a corresponding purification circle center coordinate and a corresponding system compensation value aiming at the blades with different thicknesses to obtain a phase change value, and generating the calibration table according to the corresponding relation between the blades with different thicknesses and the phase change value.
In the embodiment, the signal trigger direction of each blade is determined through the microwave signal reflected by each blade, the trigger point screening can be effectively performed on the microwave amplitude trigger point based on the signal trigger direction, the accuracy of the microwave amplitude trigger point is improved, the microwave amplitude deviation corresponding to the vibration of the blade can be effectively determined through each microwave amplitude trigger point after the trigger point screening is performed, the displacement value corresponding to the microwave amplitude trigger point can be effectively determined through the microwave amplitude deviation, the vibration amplitude of the corresponding blade can be effectively determined based on the displacement value of each microwave amplitude trigger point, the maximum microwave amplitude of each blade is matched with a pre-stored calibration table by obtaining the maximum microwave amplitude of each blade, the target blade tip distance of each blade can be effectively obtained, and the blade tip clearance and the vibration amplitude of each blade can be effectively determined based on each target blade tip distance.
Example two
Referring to fig. 5, it is a flowchart of determining a trigger direction of a signal based on a microwave signal according to a second embodiment of the present invention, where the step of step S10 is further detailed, and the method includes the steps of:
s11, respectively calculating the average value, the maximum value and the minimum value of the microwave signals reflected by the blades, and calculating the difference value between the average value and the minimum value to obtain a first difference value;
step S12, calculating a difference value between the maximum value and the minimum value to obtain a second difference value, and calculating a product between the second difference value and a threshold coefficient to obtain a deviation product value;
step S13, 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;
step S14, if the third difference is smaller than the fourth difference, determining that the signal triggering direction of the blade is a rising edge;
step S15, if the third difference is larger than or equal to the fourth difference, determining that the signal triggering direction of the blade is a falling edge;
the method comprises the following steps of calculating an average value, a maximum value and a minimum value in microwave signals reflected by each blade, calculating the average value minus the minimum value, then subtracting the product of a threshold coefficient and the deviation of the maximum value and the minimum value, and if the calculated value is smaller than the deviation of the maximum value and the average value, triggering the signal to be a rising edge, wherein the signal is abnormal and is mainly caused by compensation calculation; otherwise, the signal is normal, and the triggering direction is a falling edge;
optionally, in this embodiment, for step S20, the performing trigger point screening on the microwave amplitude trigger point according to the signal trigger direction includes:
determining the microwave amplitude trigger point with the signal trigger direction as a rising edge as a signal false trigger point, and respectively calculating a signal difference value between the signal false trigger point and an adjacent microwave amplitude trigger point;
if any signal difference value is larger than a signal threshold value, deleting the signal false trigger point;
the trigger points of the microwave signal waveforms reflected by the blades should be unified, if a false trigger point exists, the vibration of the blades and the blade tip gap calculation are affected, therefore, in the process of selecting and evaluating the trigger points, it should be ensured that the first trigger point conforms to the trigger direction of the section of data and is accurate, then whether the abnormal trigger point meets the requirement of comparing the abnormal trigger point with the size of the adjacent point is judged, and if the abnormal trigger point does not meet the requirement, the false trigger point is deleted.
In this embodiment, the signal trigger direction of each blade is determined by comparing the third difference with the fourth difference, that is, if the third difference is smaller than the fourth difference, it is determined that the signal trigger direction of the blade is a rising edge, and 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 a falling edge.
EXAMPLE III
Referring to fig. 6, a schematic structural diagram of a testing system 100 for measuring blade vibration and blade tip clearance by microwave according to a third embodiment of the present invention is shown, including: a microwave signal receiving unit 10, a trigger point screening unit 11, a displacement value determining unit 12, a vibration amplitude determining unit 13 and a blade tip gap determining unit 14, wherein:
the microwave signal receiving unit 10 is configured to receive microwave signals reflected by each blade in the engine to be calibrated, and determine a signal triggering direction of each blade according to the microwave signals reflected by each blade.
Wherein, the microwave signal receiving unit 10 is further configured to: respectively calculating the average value, the maximum value and the minimum value of the microwave signals reflected by the blades, and calculating the difference value between the average value and the minimum value to obtain a first difference value;
calculating a difference value between the maximum value and the minimum value to obtain a second difference value, and calculating a product between the second difference value and a threshold coefficient to obtain a deviation product value;
calculating a difference between the first difference and the deviation product value to obtain a third difference, and calculating a difference between the maximum value and the average value to obtain a fourth difference;
if the third difference is smaller than the fourth difference, determining that the signal triggering direction of the blade is a rising edge;
and if the third difference is larger than or equal to the fourth difference, determining that the signal triggering direction of the blade is a falling edge.
Further, the microwave signal receiving unit 10 is further configured to: and receiving microwave data reflected by each blade in the engine to be calibrated, and determining the signal waveform in the microwave data as a signal in a wave crest state as a microwave signal reflected by each blade.
And the trigger point screening unit 11 is configured to generate a microwave amplitude trigger point according to the signal trigger direction of each blade, and screen the trigger point for the microwave amplitude trigger point according to the signal trigger direction.
Wherein, the trigger point screening unit 11 is further configured to: determining the microwave amplitude trigger point with the signal trigger direction as a rising edge as a signal false trigger point, and respectively calculating a signal difference value between the signal false trigger point and an adjacent microwave amplitude trigger point;
and if any signal difference value is larger than a signal threshold value, deleting the signal false trigger point.
And the displacement value determining unit 12 is configured to determine a microwave amplitude deviation corresponding to the blade vibration according to each microwave amplitude trigger point after the trigger point screening, and determine a displacement value corresponding to the microwave amplitude trigger point according to the microwave amplitude deviation.
And the vibration amplitude determining unit 13 is configured to determine the vibration amplitude of the corresponding blade according to the displacement value of each microwave amplitude trigger point, and obtain the maximum microwave amplitude of each blade respectively.
And the blade tip clearance determining unit 14 is configured to match the maximum microwave amplitude of each blade with a pre-stored calibration table to obtain a target blade tip distance, and determine a blade tip clearance of each blade according to each target blade tip distance.
Wherein the tip-gap determining unit 14 is further configured to: carrying out null response processing on each microwave probe to obtain a null response result, and determining system compensation values of a real part and an imaginary part of each microwave probe according to the null response result;
respectively carrying out static calibration processing on blades with different thicknesses to obtain a modulated signal dynamic graph, and obtaining circle center coordinates in the modulated signal dynamic graph to obtain purified circle center coordinates, wherein the modulated signal dynamic graph is used for representing the corresponding relation between a modulated signal value and a measuring range;
and generating the calibration table according to the purified circle center coordinate and the parameter compensation value.
Optionally, the tip-gap determining unit 14 is further configured to: calculating the maximum deviation amount of the real part and the imaginary part of each microwave probe according to the null response result;
and if the maximum deviation amount of the real part and the imaginary part of the microwave probe is smaller than an error threshold value, determining the maximum deviation amount of the real part and the imaginary part of the microwave probe as the system compensation value.
Further, the tip clearance determination unit 14 is further configured to: respectively obtaining modulation signal values corresponding to the blades with different thicknesses and corresponding purified circle center coordinates;
and calculating corresponding modulation signal values, corresponding purified circle center coordinates and corresponding system compensation values aiming at the blades with different thicknesses to obtain phase change values, and generating the calibration table according to the corresponding relation between the blades with different thicknesses and the phase change values.
According to the embodiment of the invention, the signal trigger direction of each blade is determined through the microwave signal reflected by each blade, the trigger point screening can be effectively carried out on the microwave amplitude trigger point based on the signal trigger direction, the accuracy of the microwave amplitude trigger point is improved, the microwave amplitude deviation of the vibration of each blade can be effectively determined through each microwave amplitude trigger point after the trigger point screening, the displacement value of the corresponding microwave amplitude trigger point can be effectively determined through the microwave amplitude deviation, the vibration amplitude of each blade can be effectively determined based on the displacement value of each microwave amplitude trigger point, the maximum microwave amplitude of each blade is matched with a pre-stored calibration table by acquiring the maximum microwave amplitude of each blade, the target blade tip distance of each blade can be effectively obtained, and the blade tip clearance and the vibration amplitude of each blade can be effectively determined based on each target blade tip distance.
The above-mentioned embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the embodiments of the present application, and they should be construed as being included in the present application.

Claims (10)

1. A test method for measuring blade vibration and blade tip clearance by microwave, the method comprising:
receiving microwave signals reflected by each blade in the engine to be calibrated, and determining the signal triggering direction of each blade according to the microwave signals reflected by each blade;
generating a microwave amplitude trigger point according to the signal trigger direction of each blade, and screening the microwave amplitude trigger point according to the signal trigger direction;
determining microwave amplitude deviation corresponding to blade vibration according to each microwave amplitude trigger point after the trigger point screening, and determining a displacement value corresponding to the microwave amplitude trigger point according to the microwave amplitude deviation;
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;
and matching the maximum microwave amplitude of each blade with a pre-stored calibration table to obtain a target blade tip distance, and determining the blade tip clearance of each blade according to each target blade tip distance.
2. The method as claimed in claim 1, wherein before matching the maximum microwave amplitude of each blade with a pre-stored calibration table, the method further comprises:
carrying out null response processing on each microwave probe to obtain a null response result, and determining a system compensation value of a real part and an imaginary part of each microwave probe according to the null response result;
respectively carrying out static calibration processing on blades with different thicknesses to obtain a modulation signal dynamic graph, and obtaining circle center coordinates in the modulation signal dynamic graph to obtain purified circle center coordinates, wherein the modulation signal dynamic graph is used for representing the corresponding relation between a modulation signal value and a measurement range;
and generating the calibration table according to the purified circle center coordinate and the parameter compensation value.
3. The method as claimed in claim 2, wherein the step of determining the system compensation values of the real part and the imaginary part of each microwave probe according to the null response result comprises:
calculating the maximum deviation amount of the real part and the imaginary part of each microwave probe according to the null response result;
and if the maximum deviation amount of the real part and the imaginary part of the microwave probe is smaller than an error threshold, determining the maximum deviation amount of the real part and the imaginary part of the microwave probe as the system compensation value.
4. The method as claimed in claim 2, wherein the step of generating the calibration table according to the refined circle center coordinates and the parameter compensation values comprises:
respectively obtaining modulation signal values corresponding to the blades with different thicknesses and corresponding coordinates of the circle center of the purification circle;
and calculating corresponding modulation signal values, corresponding purified circle center coordinates and corresponding system compensation values aiming at the blades with different thicknesses to obtain phase change values, and generating the calibration table according to the corresponding relation between the blades with different thicknesses and the phase change values.
5. The method of claim 1, wherein determining the signal triggering direction of each blade based on the microwave signal reflected from each blade comprises
Respectively calculating the average value, the maximum value and the minimum value of the microwave signals reflected by the blades, and calculating the difference value between the average value and the minimum value to obtain a first difference value;
calculating the difference between the maximum value and the minimum value to obtain a second difference, and calculating the product between the second difference and a threshold coefficient to obtain a deviation product value;
calculating a difference between the first difference and the deviation product value to obtain a third difference, and calculating a difference between the maximum value and the average value to obtain a fourth difference;
if the third difference is smaller than the fourth difference, determining that the signal triggering direction of the blade is a rising edge;
and if the third difference is larger than or equal to the fourth difference, determining that the signal triggering direction of the blade is a falling edge.
6. The method as claimed in claim 5, wherein the step of performing trigger point screening on the microwave amplitude trigger points according to the signal trigger direction comprises:
determining the microwave amplitude trigger point with the signal trigger direction as a rising edge as a signal false trigger point, and respectively calculating a signal difference value between the signal false trigger point and an adjacent microwave amplitude trigger point;
and if any signal difference value is larger than a signal threshold value, deleting the signal false triggering point.
7. The method for testing blade vibration and blade tip clearance by microwave measurement according to any one of claims 1 to 6, wherein the receiving of the microwave signal reflected by each blade in the engine to be calibrated comprises:
and receiving microwave data reflected by each blade in the engine to be calibrated, and determining the signal waveform in the microwave data as a signal in a wave crest state as a microwave signal reflected by each blade.
8. A test system for microwave measurement of blade vibration and tip clearance, the system comprising:
the microwave signal receiving unit is used for receiving microwave signals reflected by each blade in the engine to be calibrated and determining the signal triggering direction of each blade according to the microwave signals reflected by each blade;
the trigger point screening unit is used for generating microwave amplitude trigger points according to the signal trigger direction of each blade and screening the trigger points of the microwave amplitude trigger points according to the signal trigger direction;
the displacement value determining unit is used for determining microwave amplitude deviation corresponding to blade vibration according to each microwave amplitude trigger point after the trigger point screening, and determining a displacement value corresponding to the microwave amplitude trigger point according to the microwave amplitude deviation;
the vibration amplitude determining unit is used for 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;
and the blade tip clearance determining unit is used for matching the maximum microwave amplitude of each blade with a pre-stored calibration table to obtain a target blade tip clearance and determining the blade tip clearance of each blade according to each target blade tip clearance.
9. The microwave blade vibration and tip clearance measurement test system of claim 8, wherein the tip clearance determination unit is further configured to:
carrying out null response processing on each microwave probe to obtain a null response result, and determining a system compensation value of a real part and an imaginary part of each microwave probe according to the null response result;
respectively carrying out static calibration processing on blades with different thicknesses to obtain a modulated signal dynamic graph, and obtaining circle center coordinates in the modulated signal dynamic graph to obtain purified circle center coordinates, wherein the modulated signal dynamic graph is used for representing the corresponding relation between a modulated signal value and a measuring range;
and generating the calibration table according to the purified circle center coordinate and the parameter compensation value.
10. The microwave blade vibration and tip clearance measurement test system of claim 9, wherein the tip clearance determination unit is further configured to:
calculating the maximum deviation amount of the real part and the imaginary part of each microwave probe according to the null response result;
and if the maximum deviation amount of the real part and the imaginary part of the microwave probe is smaller than an error threshold, determining the maximum deviation amount of the real part and the imaginary part of the microwave probe as the system compensation value.
CN202211199747.5A 2022-09-29 2022-09-29 Testing system for measuring blade vibration and blade tip clearance by microwave and calibration method Pending CN115452387A (en)

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CN202211199747.5A CN115452387A (en) 2022-09-29 2022-09-29 Testing system for measuring blade vibration and blade tip clearance by microwave and calibration method

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