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

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, which are characterized in that a multi-mode detector and an integrated detection probe are designed, an endoscopic video head is adopted to acquire complex internal conditions of an engine, the probe is assisted to stretch in, and an eddy current detection coil assembly works in a time-sharing and multi-mode manner; different detection modes and heating functions are switched by applying a combined excitation signal, the eddy current detection coil and the eddy current heating coil which are in a flat transparent flexible film shape are adopted to conformally fit the surface of a to-be-detected blade for eddy current detection, the shielding influence of the coils on infrared thermal imaging signals obtained by a miniature infrared camera is reduced, and the detection accuracy is improved. And the precision of an infrared thermal imaging signal is improved. 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 present invention relates to the technical field of nondestructive testing, and in particular to an in-service in-situ video eddy current infrared testing system and method for aircraft engine blades. Background Art

[0002] In order to reduce the operating temperature of aircraft engine turbine blades, the blade surface is coated with a high temperature resistant and corrosion resistant protective thermal barrier coating to extend its life. Corrosion, cracking, thinning, shedding, debonding or uneven thickness, growth of oxide layer, etc. of the thermal barrier coating material will cause the thermal barrier coating to fail and fail to protect the base material. Therefore, it is necessary to detect the possible defects of the thermal barrier coating of the engine blade. Since there are many types of defects and multiple defects may exist simultaneously in the same vertical direction of the blade, the conventional single non-destructive testing method is used for detection. Different detection sensors are required to repeatedly detect the test points. Since errors are prone to occur during the replacement of the detection sensor, it is impossible to ensure that the same fixed point can be detected every time, which is not conducive to data fusion processing, affects the analysis of the detection results, and is difficult to achieve rapid in-situ detection of aircraft engine vortex in-service blades. Summary of the invention

[0003] In order to solve the above problems, the present invention provides an in-service in-situ video eddy current infrared detection system and method for aircraft engine blades, which is implemented as follows:

[0004] An in-service in-situ video eddy current infrared detection system for aircraft engine blades, comprising an eddy current detection coil assembly connected to a multi-mode detector, an eddy current heating coil assembly, a miniature endoscope and a miniature infrared camera;

[0005] Wherein, the eddy current detection coil assembly and the eddy current heating coil assembly are both configured as flat transparent flexible films, the eddy current detection coil assembly and the eddy current heating coil assembly are spaced and arranged in parallel, the micro endoscope is arranged on either side of the left or right sides of the eddy current detection coil assembly, and the micro infrared camera is arranged directly above the eddy current detection coil assembly and the eddy current heating coil assembly;

[0006] The eddy current detection coil assembly works in time-sharing and multi-modes, and the eddy current detection coil assembly and the eddy current heating coil assembly work synchronously. Specifically, within one working cycle,

[0007] First, the eddy current detection coil assembly obtains the eddy current detection signal of the crack on the blade substrate surface by applying a single-frequency sinusoidal wave excitation signal, and the eddy current heating coil assembly does not apply excitation during this time period.

[0008] Then, the eddy current detection coil assembly applies a pulse wave excitation signal to heat the blade instantaneously with a strong electromagnetic field, and during this time period, the eddy current heating coil assembly synchronously applies a pulse wave excitation signal to heat the blade instantaneously with a strong electromagnetic field.

[0009] Next, 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, and the eddy current heating coil assembly is not excited during this time period.

[0010] Finally, the eddy current detection coil assembly applies a pulse wave excitation signal to perform instantaneous strong electromagnetic field heating on the blade, and during this time period, the eddy current heating coil assembly synchronously applies a pulse wave excitation signal to perform instantaneous strong electromagnetic field heating on the blade;

[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 spacing between the eddy current detection coil assembly and the eddy current heating coil assembly is set to 3 to 5 times the wire diameter of the eddy current detection coil assembly.

[0013] Furthermore, the miniature infrared camera is a short-focal-length near-field infrared camera, which has a good close-range shooting effect, and its focal length range is 1 to 10 cm.

[0014] 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 comprises the following steps:

[0015] Step 1: Encapsulate the sensor components in the detection system to form a detection probe, so that it can be inserted into the reserved exploration hole on the engine to perform in-service in-situ detection on the blade. The specific structure of the detection probe is as follows:

[0016] The device comprises a handle, a first probe rod, a second probe rod made of a transparent material, and a detection end with a transparent shell, which are connected in sequence.

[0017] The first probe rod and the second probe rod are bent at a certain angle to facilitate insertion into the exploration hole.

[0018] The eddy current detection coil assembly and the eddy current heating coil assembly are arranged on the detection end, the miniature infrared camera lens is arranged inside the second probe rod facing the detection end, the miniature endoscope is fixedly arranged outside the second probe rod, and its lead wire is connected to the first probe rod through a hole punched in the second probe rod and connected to the multi-mode detector;

[0019] 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, and perform mobile scanning until the entire blade to be tested is covered;

[0020] 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 of the blade substrate surface crack detection, the second window displays the eddy current sweep frequency signal of the 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;

[0021] Step 3: Perform defect evaluation, 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 mutation 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 in the infrared thermal image detection signal in the third window, it is determined that there is a debonding defect at the corresponding position.

[0022] Furthermore, signal separation is performed on the detection data obtained by the eddy current detection channel, data shearing is performed on the signal segments obtained in the time domain corresponding to different excitation signals, and the data are aggregated into a single-frequency eddy current detection database and a swept-frequency eddy current detection database, the signals in the single-frequency eddy current detection database are processed and displayed in the first window, and the signals in the swept-frequency eddy current detection database are processed and displayed in the second window.

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

[0024] 1. 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 point on the thermal barrier coating of an aircraft engine blade. The eddy current detection coil assembly works in time-sharing and multi-modes, and switches between different detection modes and heating functions by applying a combined excitation signal, thereby realizing sensor integration and miniaturization.

[0025] 2. The blades are instantaneously heated by strong electromagnetic fields using pulse wave excitation signals, which can quickly heat up and cool down without the need for additional cooling devices, thus improving detection efficiency.

[0026] 3. Use flat, transparent, flexible film-like eddy current detection coils and eddy current heating coils to conform to the surface of the blade to be tested for eddy current detection. The flat, transparent coils reduce the obstruction of the infrared thermal imaging signal obtained by the micro infrared camera, thereby improving the accuracy of the infrared thermal imaging signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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.

[0028] Figure 1 It is a schematic diagram of the detection working condition of the present invention.

[0029] Figure 2 It is a schematic diagram of the structure of the multi-mode instrument and the detection probe of the present invention.

[0030] Figure 3 It is a schematic diagram of the structure of the detection end of the detection probe of the present invention.

[0031] Figure 4 It is a simplified schematic diagram of the internal structure of the detection end of the detection probe of the present invention.

[0032] Figure 5 It is a schematic diagram of the structure rendering of the detection end of the present invention.

[0033] Figure 6 It is a schematic diagram of the combined excitation waveform of the eddy current detection coil of the present invention.

[0034] Figure 7 It is a schematic diagram of the excitation waveform of the eddy current heating coil of the present invention.

[0035] In the figure:

[0036] 10-multi-mode detector, 11-first window, 12-second window, 13-third window, 14-fourth window;

[0037] 20-detection probe, 21-handle, 22-first probe rod, 23-second probe rod, 24-transparent shell, 25-eddy current detection coil assembly, 26-eddy current heating coil assembly, 27-mini endoscope, 28-mini infrared camera;

[0038] 30-probe hole, 40-blade. DETAILED DESCRIPTION

[0039] 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.

[0040] 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.

[0041] like Figure 1-7 As shown, the present invention provides an in-service in-situ video eddy current infrared detection system for aircraft engine blades, comprising an eddy current detection coil assembly 25, an eddy current heating coil assembly 26, a miniature endoscope 27 and a miniature infrared camera 28 connected to a multi-mode detector 10;

[0042] The eddy current detection coil assembly 25 and the eddy current heating coil assembly 26 are both configured as flat transparent flexible films. The flexible film structure can be attached to the surface of the blade to be tested for heating or testing, thereby improving the uniformity of heating and the sensitivity during testing. The eddy current detection coil assembly 25 and the eddy current heating coil assembly 26 are arranged in parallel with each other, the micro endoscope 28 is arranged on either side of the left or right side of the eddy current detection coil assembly, and the micro infrared camera 28 is arranged directly above the eddy current detection coil assembly and the eddy current heating coil assembly.

[0043] The present invention adopts a flat, transparent, flexible, thin-film eddy current detection coil assembly and an eddy current heating assembly, and arranges a miniature infrared camera directly above the two, so as to overcome the infrared radiation interference problem caused by conventional coils. The miniature infrared camera is placed perpendicular to the surface to be detected, so that the field of view angle of the miniature infrared camera 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.

[0044] Reference Figure 6-7 , the accompanying drawings are schematic diagrams of the excitation signal waveforms of the eddy current detection coil assembly and the eddy current heating coil assembly respectively.

[0045] The eddy current detection coil assembly works in time-sharing and multi-modes, and the eddy current detection coil assembly and the eddy current heating coil assembly work synchronously. Specifically, within one working cycle,

[0046] First, the eddy current detection coil assembly obtains the eddy current detection signal of the crack on the blade substrate surface by applying a single-frequency sinusoidal wave excitation signal, and the eddy current heating coil assembly is not excited during this time period. By applying a single-frequency sinusoidal wave excitation signal and turning off the heating coil at the same time, mutual interference between the coils is avoided.

[0047] Then, the eddy current detection coil assembly applies a pulse wave excitation signal to perform instantaneous strong electromagnetic field heating on the blades, and during this time period, the eddy current heating coil assembly synchronously applies a pulse wave excitation signal to perform instantaneous strong electromagnetic field heating on the blades, and obtains the first infrared detection image information through a miniature infrared camera.

[0048] Next, the eddy current detection coil assembly obtains the eddy current sweep signal of the blade coating thickness by applying a multi-frequency sinusoidal wave excitation signal. During this time period, the eddy current heating coil assembly is not excited and is excited by a multi-frequency sinusoidal wave excitation signal. When detecting the coating thickness, it switches to multi-frequency, which can analyze the coating changes at different depths.

[0049] Finally, the eddy current detection coil assembly applies a pulse wave excitation signal to heat the blade with an instantaneous strong electromagnetic field, and during this time period, the eddy current heating coil assembly synchronously applies a pulse wave excitation signal to heat the blade with an instantaneous strong electromagnetic field; the second image information is quickly acquired through a miniature infrared camera. 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.

[0050] 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.

[0051] Furthermore, the detection data acquired by the eddy current detection channel is processed, and the signal segments acquired in the corresponding time domain are cut and aggregated into a single-frequency eddy current detection database and a swept-frequency eddy current detection database, and processed separately, and the generated graphs are fed back to the instrument display interface.

[0052] 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 part, affecting the transfer or distribution of heat, and then affecting the temperature distribution of infrared thermal imaging detection, affecting the infrared thermal imaging detection signal. Therefore, in this embodiment, two infrared detections are performed between the substrate crack detection and the coating thickness detection, and the frequency of the two pulse wave excitation signals is adjustable, and the detection accuracy is improved by comparative analysis at different times and multiple temperature points. According to the detection steps, the data obtained by the eddy current detection channel is pre-judged. When there are substrate cracks and thinning defects in this part, the pulse wave excitation signal is compensated and adjusted to reduce the influence of substrate cracks and thinning defects on heat transfer and distribution.

[0053] In this embodiment, a certain distance is set between the eddy current detection coil assembly 25 and the eddy current heating assembly 26. The setting of the distance enables the two coils to ensure the continuity of the temperature field in the area to be measured when heating the blade, and to avoid mutual interference between the two coils. Furthermore, the distance between the eddy current detection coil assembly and the eddy current heating coil assembly is set to 3 to 5 times the wire diameter of the eddy current detection coil assembly.

[0054] Furthermore, the miniature infrared camera 28 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, and its focal length range is 1 to 10 cm.

[0055] 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 comprises the following steps:

[0056] Step 1: Refer to the attached Figure 1 The sensor components in the detection system are packaged to form a detection probe 20, so that it can be inserted into the reserved exploration hole 30 on the engine to perform in-service in-situ detection on the blade 40. The specific structure of the detection probe is as follows:

[0057] It includes a handle 21, a first probe rod 22, a second probe rod 23 made of transparent material, and a detection end with a transparent shell 24, which are connected in sequence. The second probe rod and the transparent shell of the detection end are made of transparent material to reduce obstruction to external visual detection and infrared imaging detection.

[0058] The first probe rod 21 and the second probe rod 22 form a certain bending angle, and the bending angle is between 10° and 30°, which maximizes the flexibility and operability of the probe rod, ensures that the probe can smoothly enter the narrow exploration hole, and maintains the accurate positioning of the sensor.

[0059] The eddy current detection coil assembly 25 and the eddy current heating coil assembly 26 are arranged on the detection end, the miniature infrared camera lens is facing the detection end and is arranged in the second probe rod, the miniature endoscope is fixedly arranged outside the detection end, and its lead wire is connected to the first probe rod through a hole in the second probe rod and connected to the multi-mode detector;

[0060] 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, and perform mobile scanning until the entire blade to be tested is covered;

[0061] 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 of the blade substrate surface crack detection, the second window 12 displays the eddy current sweep frequency signal of the blade coating thickness measurement, 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;

[0062] Step 3: Defect evaluation, 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 in the infrared thermal image detection signal in the third window, it is determined that there is a debonding defect at the corresponding position. The detection signal is visualized synchronously, so that the inspection personnel can quickly obtain the inspection results.

[0063] 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 device comprises an eddy current detection coil assembly, an eddy current heating coil assembly, a miniature endoscope and a miniature infrared camera connected to a multi-mode detector; Wherein, the eddy current detection coil assembly and the eddy current heating coil assembly are both configured as flat transparent flexible films, the eddy current detection coil assembly and the eddy current heating coil assembly are spaced and arranged in parallel, the micro endoscope is arranged on either side of the left or right sides of the eddy current detection coil assembly, and the micro infrared camera is arranged directly above the eddy current detection coil assembly and the eddy current heating coil assembly; The eddy current detection coil assembly works in time-sharing and multi-modes, and the eddy current detection coil assembly and the eddy current heating coil assembly work synchronously. Specifically, within one working cycle, First, the eddy current detection coil assembly obtains the eddy current detection signal of the crack on the blade substrate surface by applying a single-frequency sinusoidal wave excitation signal, and the eddy current heating coil assembly does not apply excitation during this time period. Then, the eddy current detection coil assembly applies a pulse wave excitation signal to heat the blade instantaneously with a strong electromagnetic field, and during this time period, the eddy current heating coil assembly synchronously applies a pulse wave excitation signal to heat the blade instantaneously with a strong electromagnetic field. Next, 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, and the eddy current heating coil assembly is not excited during this time period. Finally, the eddy current detection coil assembly applies a pulse wave excitation signal to perform instantaneous strong electromagnetic field heating on the blade, and during this time period, the eddy current heating coil assembly synchronously applies a pulse wave excitation signal to perform instantaneous strong electromagnetic field heating on the blade; 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 spacing between the eddy current detection coil assembly and the eddy current heating coil assembly is set to be 3 to 5 times of the coil wire diameter of the eddy current detection coil assembly.

3. The in-service in-situ video eddy current infrared detection system for aircraft engine blades according to claim 1, characterized in that: The miniature infrared camera is a short-focal-length near-field infrared camera with good close-range shooting effect, and its focal length range is 1 to 10 cm.

4. A detection method for an in-service in-situ video eddy current infrared detection system for aircraft engine blades, using a detection system as claimed in any one of claims 1 to 3, characterized in that: Used for in-service in-situ detection of aircraft engine blades, including the following steps: Step 1: Encapsulate the sensor components in the detection system to form a detection probe, so that it can be inserted into the reserved exploration hole on the engine to perform in-service in-situ detection on the blade. The specific structure of the detection probe is as follows: The device comprises a handle, a first probe rod, a second probe rod made of a transparent material, and a detection end with a transparent shell, which are connected in sequence. The first probe rod and the second probe rod are bent at a certain angle to facilitate insertion into the exploration hole. The eddy current detection coil assembly and the eddy current heating coil assembly are arranged on the detection end, the miniature infrared camera lens is facing the detection end and is arranged in the second probe rod, the miniature endoscope is fixedly arranged outside the transparent shell, and its lead wire is connected to the first probe rod through a hole in the second probe rod and connected to the multi-mode detector; 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, and perform mobile scanning until the entire blade to be tested is covered; 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 of the blade substrate surface crack detection, the second window displays the eddy current sweep frequency signal of the 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; Step 3: Perform defect evaluation, 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 mutation 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 in the infrared thermal image detection signal in the third window, it is determined that there is a debonding defect at the corresponding position.

5. The detection method of an in-service in-situ video eddy current infrared detection system for aircraft engine blades according to claim 4, characterized in that: Signal separation is performed on the detection data obtained by the eddy current detection channel, and data shearing is performed on the signal segments obtained in the time domain corresponding to different excitation signals, and the data are aggregated into a single-frequency eddy current detection database and a swept-frequency eddy current detection database. The signals in the single-frequency eddy current detection database are processed and displayed in the first window, and the signals in the swept-frequency eddy current detection database are processed and displayed in the second window.

Images