Aero-engine blade in-service in-situ video eddy current infrared detection system

Abstract

The invention relates to the field of nondestructive testing, and discloses an aero-engine blade in-service in-situ video eddy current infrared detection system and a detection method, a multi-mode detector and an integrated detection probe are designed, a binocular endoscopic video head is adopted to obtain the complex internal condition of an engine, the probe is assisted to stretch in, and the posture of the probe is adjusted; the probe is attached to a to-be-detected surface, the eddy current detection coil assembly formed by combining a transparent coil and a ferrite magnetic ring is adopted to improve the magnetism gathering and heating performance, time-sharing and multi-mode work is achieved, and different detection modes and heating functions are switched by applying a combined excitation signal. The transparent coil reduces the shielding influence on the infrared thermal imaging signal obtained by the miniature infrared camera, and improves the precision of the infrared thermal imaging signal. According to the invention, high integration of video, eddy current and infrared sensors is realized, the probe is miniaturized, and in-service in-situ detection of various defects at the same fixed point position on a thermal barrier coating of an aero-engine blade is realized.

Description

Technical Field

[0001] The invention relates to the technical field of nondestructive testing, and in particular to an in-service in-situ video eddy current infrared testing system for aircraft engine blades. Background Art

[0002] Thermal barrier coatings for engine blades are important protective coatings for high-temperature equipment such as aircraft engines and power turbines. They play a key role in high-temperature and corrosive environments to ensure the performance and durability of blades. In high-temperature and high-pressure working environments, thermal barrier coatings are prone to defects such as substrate cracks, coating thinning, and debonding. In order to ensure the performance and life of thermal barrier coatings, regular inspections are required.

[0003] During the application process, there are situations where multiple defects appear on the same blade at the same time. In order to accurately obtain defect information, the conventional method is to replace different detection sensors for detection. Not only is the detection efficiency low and the data fusion weak, it is difficult to achieve rapid in-situ detection of refined vortex in-service blades within the complex structure of aircraft engines. Summary of the invention

[0004] In order to solve the above problems, the present invention provides an in-service in-situ video eddy current infrared detection system for aircraft engine blades, which is implemented as follows:

[0005] An in-service in-situ video eddy current infrared detection system for aircraft engine blades, comprising an integrated probe and a multi-mode detector connected to the integrated probe, wherein the detection end of the integrated probe is encapsulated with an eddy current detection coil assembly, a binocular endoscopic video camera composed of two miniature endoscopes, and a miniature infrared camera;

[0006] The eddy current detection coil assembly comprises an excitation coil and a detection coil, wherein the excitation coil and the detection coil are transparent planar spiral coils, and the excitation coil and the detection coil are wound in a double spiral structure.

[0007] Two miniature endoscopes are arranged oppositely on both sides of the ferrite core, and a miniature infrared camera is arranged just above the excitation coil and the detection coil;

[0008] The binocular endoscope video head obtains the surface area rate signal of the blade to be measured and performs posture adjustment feedback of the probe;

[0009] The eddy current detection coil assembly works in time-sharing and multi-modes, and switches the detection and heating modes through combined signal excitation;

[0010] When the eddy current detection coil assembly is heated, the miniature infrared camera acquires an infrared thermal imaging image;

[0011] The multi-mode detector is correspondingly provided with an eddy current detection channel, an infrared thermal imaging detection channel and an endoscopic video detection channel.

[0012] Furthermore, the integrated probe also includes a handle, a first probe rod, a second probe rod and a detection end shell which are connected in sequence, the first probe rod and the second probe rod are bent and connected, wherein the second probe rod and the detection end shell are both made of transparent materials.

[0013] Furthermore, the micro endoscope captures images of the blade surface to be measured from different angles to obtain a basic image of the blade surface to be measured, calculates the parallax of the obtained basic image through a preset probe posture adjustment model, determines the fit of the probe, and adjusts the probe angle according to the feedback information.

[0014] Furthermore, the combined signal excitation of one working cycle is sequentially a single-frequency sinusoidal wave excitation signal, a multi-frequency sinusoidal wave excitation signal, and a transient pulse wave excitation signal.

[0015] Furthermore, within a working cycle, the detection work of the integrated probe is specifically as follows:

[0016] S1. Endoscopic video posture adjustment: the binocular endoscopic video head obtains the surface image of the blade to be measured, and performs probe posture feedback, and adjusts the probe posture according to the feedback signal to fit the surface of the blade to be measured;

[0017] S2. Single-frequency eddy current detection: the excitation coil applies a single-frequency sinusoidal wave excitation signal and uses a detection coil to obtain an eddy current detection signal of a crack on the surface of the blade substrate;

[0018] S3, frequency sweep eddy current detection: the eddy current detection coil assembly obtains the eddy current frequency sweep signal of the blade coating thickness by applying a multi-frequency sinusoidal wave excitation signal;

[0019] S4, instantaneous heating detection: the excitation coil and the detection coil synchronously apply a pulse wave excitation signal with the same frequency to perform instantaneous strong electromagnetic field heating on the blade, and the miniature infrared camera obtains an infrared thermal imaging image.

[0020] Furthermore, the multi-mode detector acquires and displays multiple detection signals in real time in multiple windows on the same screen, specifically: the first window displays the eddy current detection signal for detecting cracks on the blade substrate surface, the second window displays the eddy current sweep frequency signal for measuring the blade coating thickness, the third window displays the infrared thermal image detection signal of the blade, and the fourth window displays the video image signal of the blade.

[0021] Furthermore, based on the single-frequency eddy current detection and swept-frequency eddy current detection results of the eddy current detection channel, the substrate cracks and coating thinning conditions in the current detection area are obtained, and then the thermal imaging data obtained by the miniature infrared camera is post-processed to eliminate infrared interference signals of cracks or coating thinning.

[0022] Furthermore, the eddy current detection coil assembly also includes a ferrite magnetic ring, the excitation coil and the detection coil are embedded in the middle of the ferrite magnetic ring, and the inner diameter of the ferrite magnetic ring is larger than the maximum diameter of the focal length range of the miniature infrared camera.

[0023] Compared with the prior art, the present application can obtain the following technical effects:

[0024] The present invention designs a multi-mode detector and an integrated detection probe to perform in-service in-situ detection of multiple defects at the same fixed position on the thermal barrier coating of an aircraft engine blade, wherein a binocular endoscopic video camera realizes the posture adjustment of the probe, thereby improving the detection sensitivity; an eddy current detection coil component adopts a special structure setting and is highly integrated with a miniature infrared camera, and performs time-sharing and multi-mode operation, thereby realizing the switching of different detection modes and heating functions to obtain different defect detection information, eliminating the occlusion effect of the coil on the acquisition of infrared thermal imaging signals, and improving the accuracy of infrared thermal imaging signals; realizing sensor integration and miniaturization; and adopting a pulse wave excitation signal to perform instantaneous strong electromagnetic field heating on the blade, which can quickly heat up and cool down without the need for additional cooling devices, thereby improving the detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the examples of the present invention or the technical solutions in the prior art or the drawings required for use in the description of the prior art, a brief introduction is given. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 It is a schematic diagram of the detection working condition of the present invention.

[0027] Figure 2 It is a schematic diagram of the structure of the multi-mode instrument and the integrated probe of the present invention.

[0028] Figure 3 It is a structural schematic diagram of the integrated probe detection end of the present invention.

[0029] Figure 4 It is a simplified schematic diagram of the internal structure of the detection end of the integrated probe of the present invention.

[0030] Figure 5 It is a schematic diagram of the structure rendering of the detection end of the present invention.

[0031] Figure 6It is a schematic diagram of the combined excitation waveform of the excitation coil of the present invention.

[0032] Figure 7 Schematic diagram of the excitation waveform of the detection coil of the present invention.

[0033] In the figure:

[0034] 10-multi-mode detector, 11-first window, 12-second window, 13-third window, 14-fourth window;

[0035] 20-integrated probe, 21-handle, 22-first probe rod, 23-second probe rod, 24-transparent shell, 25-detection coil, 26-excitation coil, 27-ferrite magnetic ring, 28-mini endoscope, 29-mini infrared camera;

[0036] 30-probe hole, 40-blade. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but only represents selected embodiments of the present invention.

[0038] The thermal barrier coating of engine blades plays an important role in aircraft engines and gas turbines. It can improve the high temperature resistance of the blades, thereby improving the efficiency and life of the engine. Detecting the integrity and performance of these coatings is critical to ensuring the reliability of the engine. Conventional detection methods include electromagnetic, ultrasonic, infrared thermal imaging, etc., which are used to detect surface cracks, peeling, post-coating or internal defects of thermal barrier coatings, etc. Due to the complex structure of thermal barrier coatings and the many types of defects that may occur, it is difficult to achieve comprehensive detection with only one detection method, and the existing integrated detection system is difficult to overcome the interference problem between detection methods. In addition, the internal structure of aircraft engines is complex, and the sensor structure used also needs to be finely designed. The traditional split type is difficult to solve in-situ detection.

[0039] An in-service in-situ video eddy current infrared detection system for aircraft engine blades, comprising an integrated probe 20 and a multi-mode detector 10 connected to the integrated probe 20, wherein the detection end of the integrated probe 20 is encapsulated with an eddy current detection coil assembly, a binocular endoscope video camera composed of two miniature endoscopes 28, and a miniature infrared camera 29;

[0040] The eddy current detection coil assembly includes an excitation coil 26 , a detection coil 25 , and a ferrite ring 27 . The excitation coil 26 and the detection coil 25 are transparent planar spiral coils, and the excitation coil 26 and the detection coil 25 are wound into a double spiral structure and embedded in the middle of the ferrite ring 27 .

[0041] Two miniature endoscopes 28 are disposed opposite to each other on both sides of the ferrite magnetic ring 27, and a miniature infrared camera 29 is disposed directly above the excitation coil 26 and the detection coil 25;

[0042] The binocular endoscope video head obtains the surface area rate signal of the blade to be measured and performs posture adjustment feedback of the probe;

[0043] The eddy current detection coil assembly works in time-sharing and multi-modes, and switches the detection and heating modes through combined signal excitation;

[0044] When the eddy current detection coil assembly is heated, the miniature infrared camera acquires infrared thermal imaging images.

[0045] In the present invention, the ferrite ring 27 makes the magnetic field generated by the excitation coil gather on the blade surface and shield the magnetic field from spreading outward, and adopts a transparent plane spiral coil wound into a double spiral structure, which can make the heating field more uniform during heating and overcome the edge heating effect. The inner diameter of the ferrite ring 27 is larger than the maximum diameter of the focal length range of the miniature infrared camera.

[0046] The miniature infrared camera 29 is set directly above the two. The transparent coil overcomes the infrared radiation interference problem caused by conventional coils. The miniature infrared camera is perpendicular to the surface to be detected, so that the field of view angle of the miniature infrared camera 29 ensures that it can detect the entire target area, overcomes the problems of imaging blur and distortion, and facilitates the identification of slight temperature changes and coating abnormalities.

[0047] The multi-mode detector 10 is correspondingly provided with an eddy current detection channel, an infrared thermal imaging detection channel and an endoscopic video detection channel to perform corresponding data acquisition and processing.

[0048] Furthermore, the micro endoscope 28 captures images of the surface of the blade 40 to be tested from different angles, obtains a basic image of the surface of the blade to be tested, calculates the parallax of the obtained basic image through a preset probe posture adjustment model, determines the fit of the probe, adjusts the probe angle according to the feedback information, and at the same time, obtains the pit signal on the blade surface to identify the pit defects on the blade surface.

[0049] Furthermore, the integrated probe 20 also includes a handle 21, a first probe rod 22, a second probe rod 23 and a transparent shell 24 at the detection end, which are connected in sequence. The first probe rod 22 and the second probe rod 23 are bent and connected to ensure that the probe can smoothly enter the narrow exploration hole 30, wherein the second probe rod 23 and the detection end shell are made of transparent materials to reduce obstruction to external visual detection and infrared imaging detection.

[0050] Reference Figure 6-7 , attached Figure 6 is a schematic diagram of the excitation signal waveform of the excitation coil, Figure 7 Schematic diagram of the excitation signal waveform of the detection coil. In one working cycle, the combined signal excitation of the excitation coil is a single-frequency sinusoidal wave excitation signal, a multi-frequency sinusoidal wave excitation signal, and a transient pulse wave excitation signal in sequence;

[0051] Furthermore, within a working cycle, the detection work of the integrated probe is specifically as follows:

[0052] S1. Endoscopic video posture adjustment: the binocular endoscopic video head obtains the surface image of the blade to be measured, and performs probe posture feedback, and adjusts the probe posture according to the feedback signal to fit the surface of the blade to be measured;

[0053] S2. Single-frequency eddy current detection: the excitation coil applies a single-frequency sinusoidal wave excitation signal and uses a detection coil to obtain an eddy current detection signal of a crack on the surface of the blade substrate;

[0054] S3. Sweep-frequency eddy current detection: The eddy current detection coil assembly obtains the eddy current sweep-frequency signal of the blade coating thickness by applying a multi-frequency sinusoidal wave excitation signal; a multi-frequency sinusoidal wave excitation signal is used for excitation, and when detecting the coating thickness, it switches to multi-frequency, which can analyze the coating changes at different depths.

[0055] S4, instantaneous heating detection: the excitation coil and the detection coil synchronously apply a pulse wave excitation signal with the same frequency to perform instantaneous strong electromagnetic field heating on the blade, and the micro infrared camera obtains infrared thermal imaging images. The pulse wave excitation signal is used for instantaneous strong electromagnetic field heating to achieve rapid heating and rapid cooling without the need for additional cooling devices.

[0056] Furthermore, the multi-mode detector 10 acquires and displays multiple detection signals in real time in multiple windows on the same screen, specifically: the first window 11 displays the eddy current detection signal for detecting cracks on the blade substrate surface, the second window 12 displays the eddy current sweep frequency signal for measuring the blade coating thickness, the third window 13 displays the infrared thermal image detection signal of the blade, and the fourth window 14 displays the video image signal of the blade.

[0057] When the blade to be tested has cracks or thinning in the vertical direction of the same fixed point, the cracks or thinning will cause the thermal conductivity of the material to change, and the heat flow may be hindered or dispersed in the cracked or thinned parts, affecting the transfer or distribution of heat, and further affecting the temperature distribution of infrared thermal imaging detection and affecting the infrared thermal imaging detection signal. Therefore, in this embodiment, according to the single-frequency eddy current detection and swept-frequency eddy current detection results of the eddy current detection channel, the substrate cracks and coating thinning conditions in the current detection area are obtained, and then the thermal imaging data obtained by the miniature infrared camera is post-processed to eliminate the infrared interference signals of cracks or coating thinning.

[0058] In this embodiment, the miniature infrared camera is a short-focal-length near-field infrared camera, which has a good close-range shooting effect and a high thermal sensitivity capable of acquiring transient heating changes.

[0059] The present invention also discloses a detection method of an in-service in-situ video eddy current infrared detection system for aircraft engine blades, which is used for in-service in-situ detection of aircraft engine blades, and the specific steps are:

[0060] Step 1: Insert the probe rod with a bent angle into the engine through the reserved exploration hole on the engine;

[0061] Step 2: Turn on the detection system, set the detection parameters, and then use the video shooting function of the micro endoscope to quickly and accurately find the blade to be tested in the complex space of the engine and press the detection end of the detection probe onto the surface of the blade to be tested;

[0062] Step 3: According to the signal feedback from the binocular endoscope video camera, the posture of the integrated probe is adjusted so that the detection end of the probe fits the blade to be tested, and the moving scanning is performed until the entire blade to be tested is covered and scanned;

[0063] Step 4: Fusion processing is performed on the detection data obtained by multiple detection channels, wherein the data obtained by the eddy current detection channel needs to separate the substrate crack detection signal and the coating thinning detection signal according to the detection mode, and the infrared detection signal needs to remove interference signals according to the substrate crack detection signal and the coating thinning detection signal;

[0064] Step 5: The multi-mode detector acquires and displays multiple detection signals in real time in multiple windows on the same screen;

[0065] Step 6: The detection signal is visualized synchronously so that the inspector can quickly obtain the detection results. Specifically, when there is an eddy current detection signal exceeding the threshold in the first window, it is determined that there is a crack defect at the corresponding position; when there is a sudden change signal in the eddy current sweep signal in the second window, it is determined that there is coating thinning at the corresponding position; when there is a discontinuous display of the infrared thermal image detection signal in the third window, it is determined that there is a debonding defect at the corresponding position.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An in-service video eddy current infrared detection system for aircraft engine blades, characterized in that: The invention comprises an integrated probe and a multi-mode detector connected to the integrated probe, wherein the detection end of the integrated probe is encapsulated with an eddy current detection coil assembly, a binocular endoscope video camera composed of two miniature endoscopes, and a miniature infrared camera; The eddy current detection coil assembly comprises an excitation coil and a detection coil, wherein the excitation coil and the detection coil are transparent planar spiral coils, and the excitation coil and the detection coil are wound in a double spiral structure. Two miniature endoscopes are arranged oppositely on both sides of the ferrite core, and a miniature infrared camera is arranged just above the excitation coil and the detection coil; The binocular endoscope video head obtains the surface area rate signal of the blade to be measured and performs posture adjustment feedback of the probe; The eddy current detection coil assembly works in time-sharing and multi-modes, and switches the detection and heating modes through combined signal excitation; When the eddy current detection coil assembly is heated, the miniature infrared camera acquires an infrared thermal imaging image; The multi-mode detector is correspondingly provided with an eddy current detection channel, an infrared thermal imaging detection channel and an endoscopic video detection channel.

2. The in-service in-situ video eddy current infrared detection system for aircraft engine blades according to claim 1, characterized in that: The integrated probe further includes a handle, a first probe rod, a second probe rod and a detection end housing which are connected in sequence, wherein the first probe rod and the second probe rod are connected in a bending manner, wherein the second probe rod and the detection end housing are both made of transparent materials.

3. The in-service in-situ video eddy current infrared detection system for aircraft engine blades according to claim 2, characterized in that: The micro endoscope captures images of the surface of the blade to be measured from different angles to obtain a basic image of the surface of the blade to be measured, calculates the parallax of the obtained basic image through a preset probe posture adjustment model, determines the fit of the probe, and adjusts the probe angle according to feedback information.

4. The in-service in-situ video eddy current infrared detection system for aircraft engine blades according to claim 3, characterized in that: In one working cycle, the combined signal excitation of the excitation coil is a single-frequency sinusoidal wave excitation signal, a multi-frequency sinusoidal wave excitation signal, and a transient pulse wave excitation signal in sequence.

5. The in-service in-situ video eddy current infrared detection system for aircraft engine blades according to claim 4, characterized in that: In one working cycle, the detection work of the integrated probe is specifically as follows: S1. Endoscopic video posture adjustment: the binocular endoscopic video head obtains the surface image of the blade to be measured, and performs probe posture feedback, and adjusts the probe posture according to the feedback signal to fit the surface of the blade to be measured; S2. Single-frequency eddy current detection: the excitation coil applies a single-frequency sinusoidal wave excitation signal and uses a detection coil to obtain an eddy current detection signal of a crack on the surface of the blade substrate; S3, frequency sweep eddy current detection: the eddy current detection coil assembly obtains the eddy current frequency sweep signal of the blade coating thickness by applying a multi-frequency sinusoidal wave excitation signal; S4, instantaneous heating detection: the excitation coil and the detection coil synchronously apply a pulse wave excitation signal with the same frequency to perform instantaneous strong electromagnetic field heating on the blade, and the miniature infrared camera obtains an infrared thermal imaging image.

6. The in-service in-situ video eddy current infrared detection system for aircraft engine blades according to claim 5, characterized in that: The multi-mode detector acquires and displays multiple detection signals in real time in multiple windows on the same screen, specifically: the first window displays the eddy current detection signal for blade substrate surface crack detection, the second window displays the eddy current sweep frequency signal for blade coating thickness measurement, the third window displays the infrared thermal image detection signal of the blade, and the fourth window displays the video image signal of the blade.

7. The in-service in-situ video eddy current infrared detection system for aircraft engine blades according to claim 5, characterized in that: According to the single-frequency eddy current detection and swept-frequency eddy current detection results detected by the eddy current detection channel, the substrate cracks and coating thinning conditions in the current detection area are obtained, and then the thermal imaging data obtained by the micro infrared camera is post-processed to eliminate infrared interference signals of cracks or coating thinning.

8. The in-service in-situ video eddy current infrared detection system for aircraft engine blades according to claim 1, characterized in that: The eddy current detection coil assembly also includes a ferrite magnetic ring, the excitation coil and the detection coil are embedded in the middle of the ferrite magnetic ring, and the inner diameter of the ferrite magnetic ring is larger than the maximum diameter of the focal length range of the miniature infrared camera.

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