A gas turbine turbine wheel disk blade root slot array eddy current testing system and method

Abstract

The application discloses a kind of gas turbine turbine disc blade root groove array eddy current detection system and method, comprising: contrast test block, test block blade root groove inner surface is equipped with different size, orientation artificial notch;Array eddy current probe, probe skeleton is consistent with blade root groove contour;Stepping device, integrated on array eddy current probe, drive probe and record the distance scanned;Array eddy current detector, excite the array eddy current probe and record impedance change.By adjusting array eddy current probe balance on contrast test block and calibrating array eddy current detection system sensitivity, realize the effective detection of turbine disc blade root groove defect.The application solves the problem that array eddy current detection sensitivity, accuracy and reliability are not high due to the complex shape of turbine disc blade root groove, large curvature, poor surface condition, variable defect orientation, unstable probe scanning speed, low defect positioning and quantitative accuracy.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of non-destructive testing of gas turbine components, and particularly relates to a gas turbine turbine disc blade root groove array eddy current testing system and method. BACKGROUND

[0002] The turbine blade of a gas turbine is a core component for converting the kinetic energy and thermal energy of gas into mechanical energy, and the mechanical energy obtained by the turbine blade is transmitted to the gas turbine rotor through the turbine disc blade root groove, wherein the turbine disc blade root groove is the only structure connecting the turbine moving blade and the gas turbine rotor, and plays a very key role, but the working environment is also extremely harsh. During operation, cracks, corrosion pits and other defects are prone to occur on the turbine disc blade root groove and the turbine blade assembly surface, which seriously affects the structural integrity and operational safety. Therefore, effective non-destructive testing of the turbine disc blade root groove is an important means to ensure the safe operation of the gas turbine.

[0003] The traditional penetration detection method can only detect open surface cracks of the turbine disc blade root groove, and cannot detect closed surface cracks and near-surface cracks. Although the magnetic powder detection can detect surface and near-surface cracks, the use range is limited due to the fact that the turbine disc is often made of non-ferromagnetic high-temperature alloy. At the same time, due to the complex shape of the turbine disc blade root groove assembly surface, the defect detection implementation and subsequent result observation during penetration and magnetic powder detection are also affected. Therefore, the array eddy current detection method has become the preferred non-destructive testing method for the turbine disc blade root groove due to its large single detection area, simultaneous detection of surface and near-surface defects, high detection sensitivity and other advantages.

[0004] However, due to the complex shape of the turbine disc blade root groove surface, the large surface curvature of some positions, and the influence of surface states such as oil stains, rust and roughness during detection, the sensitivity and reliability of the array eddy current detection have always been low. At the same time, due to the variability of defect orientation, the array eddy current detection has high requirements for sensitivity in all directions, and cannot have the problem of being unable to detect some oriented defects. SUMMARY

[0005] The purpose of the present application is to provide a gas turbine turbine disc blade root groove array eddy current testing system and method, which aims to solve the problems of low sensitivity, accuracy and reliability of array eddy current detection caused by the complex shape of the turbine disc blade root groove surface, the large surface curvature, the poor surface condition, the variable defect orientation, and the unstable probe scanning speed, low defect positioning and quantitative accuracy.

[0006] In order to achieve the above purpose, the present application adopts the following technical solutions:

[0007] A gas turbine turbine disk blade root groove array eddy current detection system comprises a contrast test block, an array eddy current probe, a stepping device and an array eddy current detector.

[0008] The contrast test block comprises a test block base and a notch arranged on the inner surface of the blade root groove of the test block base, and the blade root groove on the test block base has the same cross-sectional shape and size as the blade root groove of the turbine disk to be detected.

[0009] The array eddy current probe comprises a probe skeleton and an array eddy current coil, the probe skeleton is matched with the shape of the blade root groove and is used for being inserted into the inside of the blade root groove and leaving a set gap, and the array eddy current coil is arranged on the outer surface of the probe skeleton.

[0010] The stepping device comprises a coding device and a driving device, the coding device is integrated on the probe skeleton and records the distance scanned by the array eddy current probe, and the driving device is used for driving the array eddy current probe to scan along the axial direction of the turbine disk blade root groove.

[0011] The array eddy current detector is used for exciting the array eddy current probe to generate an eddy current on the detection surface of the turbine disk blade root groove, recording the influence of the change of the eddy current field intensity caused by the defects on the detection surface on the impedance change of the array eddy current probe, determining the depth of the defects according to the impedance change, and simultaneously having a C-scan function and a CT-scan function.

[0012] The further improvement of the present application is that the contrast test block is processed with a series of artificial notches of different sizes and orientations at different cross-sectional positions along the blade root groove.

[0013] The further improvement of the present application is that the orientation of the artificial notch is parallel to the axial direction of the blade root groove, perpendicular to the axial direction of the blade root groove or 45 degrees to the axial direction of the blade root groove, and at least one through groove in the artificial notch is perpendicular to the axial direction of the blade root groove.

[0014] The further improvement of the present application is that the length of the artificial notch is 1mm-10mm, the depth of the notch is 0.1mm-5mm, and the width of the notch is not greater than 0.15mm; and the interval of the artificial notch is 1mm-10mm.

[0015] The further improvement of the present application is that the periphery of the array eddy current probe skeleton is attached with an elastic body matched with the shape of the probe skeleton, and the thickness of the elastic body is greater than the gap between the array eddy current probe skeleton and the turbine disk blade root groove.

[0016] The further improvement of the present application is that the array eddy current coil is arranged at the interface position between the array eddy current probe skeleton and the elastic body along the shape of the array eddy current probe skeleton, the length of the array eddy current coil group is not less than one half of the arc surface length of the turbine disk blade root groove, the array eddy current coil adopts two-row staggered coil arrangement, each coil can be used as an exciting coil and a receiving coil, and the minimum center distance of the array eddy current coil is not greater than 4 times the length of the smallest defect to be detected.

[0017] The further improvement of the present application is that the encoding device is fixed on the array eddy current probe frame, the encoding device is positioned by the contact of the roller or the pull wire encoding device with the turbine disc blade root groove, and is connected to the encoder interface on the array eddy current detector through the cable.

[0018] The further improvement of the present application is that the driving device drives the probe to advance through the roller in contact with the turbine disc blade root groove, and is integrated with the roller type encoding device.

[0019] The further improvement of the present application is that the array eddy current detector has at least 64 array channels, and is integrated with a multiplexing module; the amplitude resolution of the eddy current signal of the array eddy current detector is not less than 16 bits.

[0020] An array eddy current detection method for a turbine disc blade root groove of a gas turbine, which is based on the array eddy current detection system for the turbine disc blade root groove of the gas turbine, and comprises the following steps:

[0021] The array eddy current probe is slid into and placed in the unnotched position of the blade root groove of the contrast test block, the array eddy current detector is used to excite the emission and reception of the induced electromagnetic field of the array eddy current probe, and the array eddy current detector is used to balance the coils of the array eddy current probe.

[0022] The array eddy current probe is made to uniformly scan the blade root groove of the contrast test block along the axial direction at a set scanning speed by using the stepping device, and the notched defects and the through groove are displayed on the C-scan image of the array eddy current detector, the angle between the notched signal and the lift-off signal is made to be vertical by changing the excitation frequency, the lift-off signal is adjusted to be horizontal, the C-scan imaging effect of the instrument is observed at the same time, and the impedance image and the C-scan image are both clearly displayed through comprehensive adjustment; the notched defects are detected at least three times by using the selected scanning speed to scan the notches on the contrast test block, so as to ensure that the notched defects can be detected each time; after the adjustment is completed, the detection parameters are saved in the array eddy current detector.

[0023] When the turbine disc blade root groove is actually detected, the array eddy current probe is stably placed in the turbine disc blade root groove, the coils are tightly combined with the surface to be detected, and the scanning speed is kept uniform; the suspicious defects found are identified and recorded through the C-scan image and the impedance image.

[0024] Compared with the prior art, the present application has at least the following beneficial technical effects:

[0025] The application provides a gas turbine turbine disc blade root groove array eddy current detection system and method, which compares test blocks and a series of artificial grooves of different sizes and orientations and through grooves, is used for simulating groove surfaces of turbine disc blade root grooves and defects of various orientations, is used for checking detection sensitivity of different orientation defects, and coil consistency of the array eddy current probe; the array eddy current probe framework is consistent with the shape of the blade root groove, ensuring the consistency of the array eddy current probe coil and the turbine disc blade root groove detection surface; the array eddy current coil adopts two-row staggered coil arrangement, ensuring the consistency of the detection sensitivity in the array eddy current probe scanning range; the driving device and the coding device in the stepping device also ensure the stability of the probe scanning speed and the accuracy of defect positioning and quantification in the detection process. The above technical features are organically integrated to form the application, realizing high sensitivity, high accuracy and high reliability detection of the gas turbine turbine disc blade root groove defects. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a schematic diagram of a gas turbine turbine disc blade root groove array eddy current detection system of the application;

[0027] Figure 2 It is a schematic diagram of the array eddy current coil in the gas turbine turbine disc blade root groove array eddy current detection system of the application;

[0028] Figure 3 It is a schematic diagram of the array eddy current probe in the gas turbine turbine disc blade root groove array eddy current detection system of the application;

[0029] Figure 4 It is a flowchart of the gas turbine turbine disc blade root groove array eddy current detection method of the application.

[0030] BRIEF DESCRIPTION OF DRAWINGS:

[0031] 1-comparison test block, 11-test block base body, 12-groove, 2-array eddy current probe, 21-probe framework, 22-array eddy current coil, 23-elastic body, 24-array eddy current coil group; 3-stepping device, 31-coding device, 32-driving device, 4-array eddy current detector. DETAILED DESCRIPTION

[0032] In the following, only certain exemplary embodiments are simply described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the application. Therefore, the drawings and the description are considered to be essentially exemplary rather than limiting.

[0033] In the description of the application, it should be understood that the orientation or positional relationship indicated by terms such as "central", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the purpose of facilitating the description of the application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application.

[0034] In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0035] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection, or communication; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0036] In the present application, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature to the second feature can include the direct contact of the first and second features, or can include the contact of the first and second features through another feature between them. Moreover, the "upper", "upper" and "upper" of the first feature to the second feature include the first feature above and obliquely above the second feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The "below", "below" and "below" of the first feature to the second feature include the first feature above and obliquely above the second feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0037] It should also be understood that the terms used in the specification of the present application are only for the purpose of describing specific embodiments and do not intend to limit the present application. As used in the specification and the appended claims of the present application, unless otherwise clear from the context, the singular form "a", "an" and "the" is intended to include the plural form.

[0038] It should be further understood that the term "and / or" as used herein in the specification and in the claims, unless otherwise specified, means any one of the associated listed items or a combination of any of the associated listed items.

[0039] The various structural diagrams according to the disclosed embodiments of the present application are shown in the accompanying drawings. These diagrams are not drawn to scale, in which certain details are shown exaggerated in scale for purposes of clarity and understanding, and certain other details are omitted. The shapes and relative sizes of the various regions, layers, and the relative positions of the regions / layers shown in the drawings are merely examples and can deviate in actuality due to manufacturing tolerances or technical limitations, and regions / layers with different shapes, sizes, and relative positions can be additionally designed by those skilled in the art according to actual needs.

[0040] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0041] Embodiments

[0042] As Figures 1-3 shown, the present application provides a gas turbine turbine disk blade root groove array eddy current testing system, which comprises a comparison test block 1, an array eddy current probe 2, a stepping device 3, and an array eddy current detector 4.

[0043] The comparison test block 1 comprises a test block base body 11 and a notch 12 arranged on the inner surface of the blade root groove of the test block base body. The cross-sectional shape and size of the blade root groove on the test block base body are the same as those of the blade root groove to be detected, and the axial length of the blade root groove is set according to actual needs. A series of artificial notches 12 with different sizes and orientations are machined inside the blade root groove of the comparison test block 1 at different cross-sectional positions of the blade root groove, which are used to determine the sensitivity and resolution of the array eddy current testing.

[0044] The array eddy current probe 2 comprises a probe skeleton 21 and an array eddy current coil 22. The probe skeleton 21 is in conformity with the shape of the blade root groove, can be smoothly inserted into the inside of the blade root groove, and has a set gap reserved, and the array eddy current coil 22 is arranged on the outer surface of the probe skeleton.

[0045] The stepping device 3 comprises a coding device 31 and a driving device 32. The coding device 31 is integrated on the skeleton of the array eddy current probe 2, and the driving device 32 is used to drive the probe to scan along the axial direction of the blade root groove of the turbine disk. Preferably, the driving device 32 can be automatically driven.

[0046] The array eddy current detector 4 is used to excite the array eddy current probe to generate eddy current on the detection surface of the turbine disk blade root groove, and record the influence of the change of the eddy current field intensity caused by the defects on the detection surface on the impedance change of the array eddy current probe, and determine the depth of the defects according to the impedance change; at the same time, the array eddy current detector 4 has a C-scan function CT scanning function, and the length, position and orientation of the defects can be obtained according to the C-scan image.

[0047] In some embodiments, a series of artificial grooves 12 with different sizes and orientations are machined along different cross-sectional positions of the blade root groove of the contrast test block 1, which are used to verify the detection sensitivity, resolution and array element consistency of the array eddy current probe.

[0048] Preferably, the orientations of the artificial grooves 12 are generally parallel to the axial direction of the blade root groove, perpendicular to the axial direction of the blade root groove, or at an angle of 45° to the axial direction of the blade root groove, which are used to verify the detection sensitivity of the array eddy current probe to defects with different orientations.

[0049] Preferably, the length of the artificial groove 12 is 1mm-10mm, the groove depth is 0.1mm-5mm, and the groove width is not greater than 0.15mm, which are used to simulate the size of the actual crack and verify the detection sensitivity of the array eddy current.

[0050] Preferably, the spacing of the artificial groove 12 is 1mm-10mm, which is used to verify the resolution of the array eddy current probe.

[0051] In some embodiments, at least one of the artificial grooves 12 is a through groove perpendicular to the axial direction of the blade root groove, which is used to verify the array element consistency of the array eddy current probe.

[0052] In some embodiments, the base material, heat treatment state and machining method of the contrast test block 1 are the same as or similar to those of the turbine disk blade root groove to be detected, and the inner surface roughness of the blade root groove of the contrast test block 1 is consistent with that of the turbine disk blade root groove to be detected, so that the detection parameters obtained after adjustment on the contrast test block are consistent with the sensitivity and accuracy in actual detection.

[0053] In some embodiments, an elastic body 23 is attached to the periphery of the array eddy current probe skeleton 21, and the thickness of the elastic body 23 is greater than the gap between the array eddy current probe skeleton 21 and the turbine disk blade root groove, and is generally not greater than 1.5mm. The array eddy current probe skeleton 21 is stably assembled into the turbine disk blade root groove, and at the same time, the detection sensitivity of the array eddy current probe 2 is not seriously reduced.

[0054] In some embodiments, the array eddy current coil 22 is arranged along the array eddy current probe skeleton 21 profile at the interface position between the array eddy current probe skeleton 21 and the elastic body 23, the length of the array eddy current coil group 24 is not less than one half of the length of the arc surface of the turbine disc blade root groove, the array eddy current coil 22 adopts two-row staggered coil arrangement, each coil can be used as an excitation coil and a receiving coil, a vortex field in different directions is formed between the excitation coil and the receiving coil, and effective detection of defects in different orientations and near surfaces and accurate identification of the defect extension direction are realized.

[0055] Preferably, the minimum center distance of the array eddy current coil 22 is not greater than 4 times the length of the smallest defect to be detected, so as to ensure the minimum defect detection capability and defect resolution.

[0056] In some embodiments, the encoding device 31 is fixed on the array eddy current probe skeleton 21, the encoding device 31 is positioned by contacting the turbine disc blade root groove through a roller or a wire encoding mode, and the other end is connected to the encoder interface on the array eddy current detector 4 through a cable line, so as to determine the position and size of the detected defect.

[0057] In some embodiments, the driving device 32 can drive the probe to advance by contacting the roller with the turbine disc blade root groove, and the driving device 32 can also be integrated with the roller type encoding device, so as to ensure the stability of the scanning speed of the array eddy current probe during scanning.

[0058] Preferably, the driving device 32 is composed of two roller motors, contacts the inner surface of the turbine disc blade root groove, and drives the array eddy current probe 2 to scan along the turbine disc blade root groove in the axial direction by relying on the friction between the roller motor wheel and the inner surface.

[0059] In some embodiments, the array eddy current detector 4 should have at least 64 array channels, and is integrated with a multiplexing module, so as to ensure the coverage area of the array eddy current probe coil group 24 in one scan and reduce the requirement for the number of hardware channels of the array eddy current detector 4.

[0060] Preferably, the amplitude resolution of the eddy current signal of the array eddy current detector 4 should be not less than 16 bits, so as to ensure the accuracy of the array eddy current detection data.

[0061] Embodiment 2

[0062] As shown in Figure 4 The present application provides a gas turbine turbine disc blade root groove array eddy current detection method, which comprises the following steps:

[0063] Step S1: sliding and placing the array eddy current probe 2 into the blade root groove of the contrast test block 1 without a groove, exciting the array eddy current probe 2 to emit and receive an induced electromagnetic field by using the array eddy current detector 4, and balancing the array eddy current coil 22 by using the array eddy current detector 4.

[0064] Step S2: The array eddy current probe 2 is made to move along the blade root groove of the contrast test block 1 at a set scanning speed by the stepping device 3, and the notch 12 and the through groove 12 are displayed on the C-scan image of the array eddy current detector 4. The angle between the notch 12 signal and the lift-off signal is made as vertical as possible by changing the excitation frequency and other parameters, and then the lift-off signal is adjusted to the horizontal position. At the same time, the C-scan imaging effect of the array eddy current detector 4 is observed, and the impedance image and the C-scan image are adjusted comprehensively to ensure that they are clearly displayed. The selected scanning speed is used to scan the notch 12 on the contrast test block 1 for at least 3 times to ensure that the notch 12 can be detected each time. After the adjustment is completed, the detection parameters are saved in the array eddy current detector 4.

[0065] Step S3: When the turbine disc blade root groove is actually detected, the array eddy current probe 2 is stably placed in the turbine disc blade root groove, so that the coil 22 is closely attached to the surface to be detected, and the scanning speed is kept uniform. The suspected defects found are identified and recorded through the C-scan image and the impedance image. In order to reduce the interference caused by the edge effect of the eddy current detection, a high-pass filter is used to suppress the interference signal during detection.

[0066] Example 3

[0067] 1. Preparation of the contrast test block

[0068] The 9FA type gas turbine turbine disc blade root groove is taken as the detection object, and the contrast test block base body 11 is prepared to ensure that the cross-sectional shape and size of the contrast test block 1 are the same as those of the turbine disc blade root groove to be detected, and the axial length of the contrast test block 1 is not less than 200 mm.

[0069] A series of artificial notches 12 with different sizes and orientations are processed on the inner surface of the blade root groove of the contrast test block base body 11. The orientations of the artificial notches 12 are parallel to the axial direction of the blade root groove, perpendicular to the axial direction of the blade root groove, and 45° to the axial direction of the blade root groove. The length is 5 mm, the depth is 0.2 mm, the width is 0.15 mm, and the pitch is 10 mm. At the same time, a through groove perpendicular to the axial direction is processed at a distance of 50 mm from one end of the contrast test block 1.

[0070] 2. Design of array eddy current probe

[0071] The probe skeleton 21 is designed to match the shape of the 9FA type gas turbine turbine disc blade root groove, and a 1 mm gap is reserved.

[0072] The array eddy current coil 22 is arranged on the outer surface of the probe skeleton 21, and the elastic body 23 is arranged on the periphery. The thickness of the elastic body 23 is greater than 1 mm and less than 1.5 mm.

[0073] The length of the array eddy current coil group 24 is not less than 100 mm, and the coil is arranged in a two-row staggered manner with a center distance of 3 mm.

[0074] 3. Step device

[0075] The encoding device 31 is integrated on the array eddy current probe skeleton 21, and is positioned by contacting the turbine disc blade root groove through the encoding mode of the roller or the pull wire, and the other end is connected to the encoder interface on the array eddy current detector 4 through the cable.

[0076] The driving device 32 is composed of two roller motors, and is in contact with the inner surface of the turbine disc blade root groove, and drives the array eddy current probe 2 to scan along the turbine disc blade root groove in the axial direction by relying on the friction between the roller motor wheel and the inner surface, so as to ensure that the probe can be driven to scan along the turbine disc blade root groove in the axial direction.

[0077] 4. Array eddy current detector

[0078] The array eddy current detector 4 has 64 array channels, and is integrated with a multiplexing module, has C-scan function and CT-scan function, and the amplitude resolution of the signal is 16 bits. It is used for exciting the array eddy current probe to generate eddy current on the detection surface of the turbine disc blade root groove, recording the influence of the change of the eddy current field intensity caused by the defect on the detection surface on the impedance change of the array eddy current probe, and extracting and recording the length, depth, position and orientation of the defect.

[0079] 5. Debugging of array eddy current detection system

[0080] The array eddy current probe 2 is placed at a non-grooving position of the contrast test block 1, the array eddy current detector 4 is used to excite the array eddy current probe 2 to emit and receive the induced electromagnetic field, and the array eddy current detector 4 is used to balance the array eddy current coil 22.

[0081] The step device 3 is used to scan the blade root groove of the contrast test block 1 at a constant speed in the axial direction, and the grooving 12 and the through groove 12 are displayed on the C-scan image of the array eddy current detector 4. By changing the excitation frequency and the like, the angle between the grooving 12 signal and the lift-off signal is made as vertical as possible, and then the lift-off signal is adjusted to a horizontal position, while the C-scan imaging effect of the array eddy current detector 4 is observed, and the impedance image and the C-scan image are adjusted comprehensively to ensure that they are clearly displayed. The grooving 12 on the contrast test block 1 is scanned at least 3 times with the selected scanning speed to ensure that the grooving 12 can be detected each time.

[0082] After the debugging is completed, the detection parameters are saved in the array eddy current detector 4.

[0083] 6. Actual detection

[0084] The array eddy current probe 2 is stably placed in the turbine disc blade root groove, and the coil 22 is tightly attached to the surface to be detected.

[0085] The scanning is carried out at a uniform speed, and the suspicious defects in the C-scan image and the impedance image are recorded.

[0086] The high pass filter is used to suppress the interference signal caused by the edge effect.

[0087] The above shows and describes the basic principles and main features of the present application and the advantages of the present application, and it is obvious for those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be regarded as exemplary and non-limiting in any respect, and the scope of the present application is defined by the appended claims rather than the above description, and it is intended to encompass all changes falling within the meaning and scope of the equivalent elements of the claims. Any reference signs in the claims should not be regarded as limiting the claims involved.

[0088] Furthermore, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the present specification is described in this way only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be properly combined to form other embodiments that those skilled in the art can understand. The above is only to illustrate the technical idea of the present application, and cannot limit the protection scope of the present application, and any modification made on the basis of the technical solutions according to the technical idea of the present application falls within the protection scope of the claims of the present application.

Claims

1. A gas turbine disk blade root groove array eddy current detection system, characterized in that, Includes a comparison test block, an array eddy current probe, a stepping device, and an array eddy current detector; The comparative test block includes a test block substrate and a groove set on the inner surface of the blade root groove of the test block substrate. The cross-sectional shape and size of the blade root groove of the test block substrate are the same as the cross-sectional shape and size of the blade root groove of the turbine disk to be tested. The array eddy current probe includes a probe frame and an array eddy current coil. The probe frame is fitted with the shape of the blade root groove and is used to insert into the blade root groove with a set gap. The array eddy current coil is arranged on the outer surface of the probe frame. The stepping device includes an encoding device and a driving device; the encoding device is integrated on the probe frame and records the distance scanned by the array eddy current probe, while the driving device is used to drive the array eddy current probe to scan along the axial direction of the turbine disk blade root groove. The array eddy current detector is used to excite the array eddy current probe to generate eddy currents on the root groove detection surface of the turbine disk blade, and record the influence of the change in eddy current field intensity caused by defects on the detection surface on the impedance change of the array eddy current probe. The depth of the defect is determined based on the impedance change. The array eddy current detector also has a C-scan function. The comparison test block has a series of grooves of different sizes and orientations machined at different cross-sectional positions along the blade root groove; the orientation of the grooves is parallel to the blade root groove axis, perpendicular to the blade root groove axis, or at 45° to the blade root groove axis; at least one through groove is present in the grooves, and the through groove is perpendicular to the blade root groove axis. The probe frame is surrounded by an elastic body that conforms to the shape of the probe frame. The thickness of the elastic body is greater than the gap between the probe frame and the turbine blade root groove. The arrayed eddy current coils are set along the outer shape of the probe frame at the interface between the probe frame and the elastic body. The length of the arrayed eddy current coil group is not less than half the length of the arc surface of the turbine blade root groove. The arrayed eddy current coils adopt a two-row staggered coil arrangement. The minimum center distance of the arrayed eddy current coils is not greater than 4 times the length of the minimum defect to be detected.

2. The eddy current detection system for the root groove array of a gas turbine disk blade according to claim 1, characterized in that, The length of the groove is 1mm to 10mm, the depth of the groove is 0.1mm to 5mm, and the width of the groove is no more than 0.15mm; the spacing between the grooves is 1mm to 10mm.

3. The eddy current detection system for the root groove array of a gas turbine disk blade according to claim 1, characterized in that, The encoding device is fixed on the probe frame. The encoding device is positioned by contacting the turbine disk blade root groove through a roller or wire encoding method, and is connected to the encoding device interface on the array eddy current detector through a cable.

4. The eddy current detection system for the root groove array of a gas turbine disk blade according to claim 3, characterized in that, The drive unit can advance by driving an array of eddy current probes through rollers that contact the root grooves of the turbine disc blades, or it can be integrated with an encoding device.

5. The eddy current detection system for the root groove array of a gas turbine disk blade according to claim 1, characterized in that, The array eddy current detector has at least 64 array channels and integrates a multiplexing module; the amplitude resolution of the eddy current signal of the array eddy current detector is not less than 16 bits.

6. A method for detecting eddy currents in a gas turbine disk blade root groove array, characterized in that, This method is based on a gas turbine disk blade root groove array eddy current detection system according to any one of claims 1 to 5, comprising: The array eddy current probe was slid into and placed in the ungrooved position of the blade root groove of the comparison test block substrate. The array eddy current detector was used to excite the array eddy current probe to emit and receive the induced electromagnetic field, and the array eddy current coil was balanced using the array eddy current detector. A stepping device is used to make the array eddy current probe sweep along the axial direction of the blade root groove of the comparison test block at a set scanning speed. The groove defects and through grooves are displayed on the C-scan image of the array eddy current detector. By changing the excitation frequency, the angle between the groove signal and the lift-off signal is made perpendicular. Then, the lift-off signal is adjusted to a horizontal position. At the same time, the C-scan imaging effect of the array eddy current detector is observed. Comprehensive adjustments are made to ensure that both the impedance image and the C-scan image are clearly displayed. The groove on the comparison test block is scanned at least 3 times at the selected scanning speed to ensure that the groove defects are detected each time. After the debugging is completed, the detection parameters are saved in the array eddy current detector. During the actual inspection of the turbine blade root groove, the array eddy current probe is stably placed in the turbine blade root groove, so that the array eddy current coil is in close contact with the surface to be inspected, and the scanning speed is kept uniform; the suspected defects found are identified and recorded by C-scan images and impedance images.

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