Fir-tree type blade root high-efficiency detection device and method based on plane wave ultrasonic technology

Abstract

The present invention relates to a fir-tree-shaped blade root efficient detection device based on plane wave ultrasonic technology, including a splitter, a combined phased array ultrasonic probe and a combined phased array ultrasonic wedge; the combined phased array ultrasonic probe is composed of three independent sub-probes arranged in parallel linear array arrays; the interface at one end of the splitter is connected to the combined phased array ultrasonic probe through a cable, and the probe and instrument interface at the other end are connected to the phased array ultrasonic instrument; the three sub-probes are installed on the combined phased array ultrasonic wedge, and the combined phased array ultrasonic wedge is composed of three sub-wedges, and each sub-probe corresponds to a sub-wedge. The beneficial effect of the present invention is that the present invention uses three independent parallel linear array arrays to arrange sub-probes to form a combined phased array ultrasonic probe, which avoids missed detection of blade root defects or detection rework caused by probe placement deviation during manual detection and installation deviation of the scanner probe clamping device during automatic detection.

Description

Technical Field

[0001] The invention relates to a method for detecting fir-tree-shaped blade roots of large-scale thermal power and nuclear power units, and in particular to a device and method for efficiently detecting fir-tree-shaped blade roots based on plane wave ultrasonic technology. Background Art

[0002] The detection of fir-tree blade roots is generally carried out using conventional ultrasonic probes or linear array phased array ultrasonic probes. The detection of the entire blade root area is completed by using multiple different probes to detect different areas of the blade root. Conventional ultrasonic detection uses a shear wave probe to detect the inner and outer curved surfaces of the blade, and a longitudinal wave probe to detect the shoulder areas on both sides of the blade.

[0003] The traditional phased array ultrasonic detection scheme for fir-tree blade roots uses multiple linear array probes. A linear array probe refers to a probe in which all the chips are arranged in a straight line. The detection is generally divided into four detection sequences. In sequence 1, the phased array linear array probe with an angled wedge is placed on the outer arc surface of the blade to detect defects on the inner arc surface of the blade root. In sequence 2, the phased array linear array probe with an angled wedge is placed on the inner arc surface of the blade to detect defects on the outer arc surface of the blade root. In sequence 3, the phased array linear array probe with an angled wedge is placed on the shoulders on both sides of the blade close to the inner arc side to detect defects on the outer arc surface at both ends of the blade root. In sequence 4, the phased array linear array probe without a wedge is placed on the shoulders on both sides of the blade close to the inner arc side to detect defects on the inner arc surface at both ends of the blade root. Each sequence of the traditional phased array ultrasonic detection scheme uses the imaging method of phased array ultrasonic fan scanning.

[0004] Conventional ultrasonic blade root detection, because the probe angle of conventional ultrasonic detection is single and fixed, the area covered by the sound beam is limited, and the sensitivity of ultrasonic detection is highest when the sound beam is perpendicular to the defect, and lowest when the sound beam is parallel to the defect. Therefore, for conventional ultrasound, the unique detection angle also makes conventional ultrasonic detection insensitive to some directional defects. Conventional ultrasound uses A-type display imaging, and the image can only display information such as signal amplitude and sound range. During the fir-tree type blade root detection process, due to the complex structure of the blade root, in addition to the defect signal, there will be some structural display signals. The limitations of A-type scanning make it difficult to quickly and accurately distinguish the above signals, which increases the difficulty of defect identification during the detection process. The bottom surface of the conventional ultrasonic probe is a hard structure. When moving on the curved blade body of the blade, the bottom surface of the probe and the blade surface may not fit tightly, resulting in poor coupling during detection, thereby affecting the quality of the detection signal.

[0005] Traditional blade root phased array ultrasonic testing uses a sector scanning imaging method. Because the detection process uses a phased array ultrasonic probe with a linear array of chips, although the sector scanning method can achieve detection imaging at multiple angles, the linear phased array ultrasonic probe can only be imaged in one plane and cannot achieve three-dimensional imaging. Therefore, during the detection process, if the probe is tilted to a certain extent due to the installation of the scanner or the tilt of the probe when the inspector holds the probe, it will cause a certain deviation between the actual sound beam emitted by the probe and the sound beam direction required in the detection plan, which may eventually cause defects to be missed. The bottom surface of the traditional phased array ultrasonic probe is a hard structure. When moving on the curved blade body of the blade, the bottom surface of the probe and the blade surface may not fit tightly, resulting in poor coupling during detection, thereby affecting the quality of the detection signal. In addition, the traditional phased array ultrasonic scanning is still based on ultrasonic pulse reflection detection technology. The probe wafer used in blade root detection is relatively small. Due to the structure of the blade root, the propagation distance of ultrasonic waves in the blade root is relatively long and there is a certain attenuation. The distance between the blade root defect echo and the blade root structure reflection wave is relatively close. Due to the limitations of the phased array ultrasonic sector scanning imaging algorithm and the nature of the instrument hardware performance, the signal-to-noise ratio of the phased array ultrasonic sector scanning imaging during traditional blade root detection is relatively poor, which affects the identification of some minor defects in the blade root. Therefore, the existing technology has the following problems:

[0006] 1. The detection speed is slow, and multiple probes and multiple detection sequences are required to complete the detection of the entire blade root area;

[0007] 2. During manual inspection, the inspection effect is closely related to the inspection personnel's operating techniques. If the inspection personnel's operating techniques are not meticulous enough, defects may be missed. During automatic inspection, the progress of the scanner also has a great impact on the reliability of the inspection results.

[0008] 3. The poor contact between the blade root camber curvature and the probe surface affects the detection effect;

[0009] 4. Due to the limitations of the imaging method, the signal-to-noise ratio of the detection data is not high, which affects the identification of tiny defects. Summary of the invention

[0010] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a fir-tree-shaped blade root efficient detection device and method based on plane wave ultrasonic technology to quickly and efficiently detect the fir-tree-shaped blade roots of large thermal power and nuclear power units.

[0011] This fir-tree-shaped blade root efficient detection device based on plane wave ultrasonic technology includes a splitter, a combined phased array ultrasonic probe and a combined phased array ultrasonic wedge; the combined phased array ultrasonic probe is composed of three independent sub-probes arranged in parallel linear array arrays; the interface at one end of the splitter is connected to the combined phased array ultrasonic probe through a cable, and the probe and instrument interface at the other end are connected to the phased array ultrasonic instrument; the three sub-probes are installed on the combined phased array ultrasonic wedge, and the combined phased array ultrasonic wedge is composed of three sub-wedges, and each sub-probe corresponds to a sub-wedge; a flexible coupling layer that can be injected with water is provided at the bottom of the combined phased array ultrasonic wedge, and the flexible coupling layer fits the blade surface; the sub-wedge in the middle of the combined phased array ultrasonic wedge is provided with a first inclination angle in the length direction; the sub-wedges on both sides of the combined phased array ultrasonic wedge are provided with a second inclination angle in the length direction, and the sub-wedges on both sides are also provided with a third inclination angle in the width direction.

[0012] Preferably, one end of the splitter is provided with three interfaces, which are respectively connected to three sub-probes of the combined phased array ultrasonic probe through cables.

[0013] Preferably, an operation button for selecting the probe excitation mode is provided on the splitter, and the operation button includes a combination button and an independent button.

[0014] Preferably, the first inclination angle and the second inclination angle are the same, both of which are 36°-39°.

[0015] Preferably, the third inclination angle is 5-10°.

[0016] Preferably, the sub-wedges on both sides of the combined phased array ultrasonic wedge are in a mirror image relationship in the width direction.

[0017] Preferably, a sound insulation material is provided on the side of the sub-wedge in the middle of the combined phased array ultrasonic wedge.

[0018] Preferably, sound insulation materials are provided on the side portions of the sub-wedges on both sides of the combined phased array ultrasonic wedge.

[0019] The detection method of the fir-tree-shaped blade root high-efficiency detection device based on plane wave ultrasonic technology comprises the following steps:

[0020] S1. Use simulation software to create the detection process, including the range of plane wave imaging, the location of the probe and the trajectory of movement during detection; the imaging resolution is set to 0.5 mm or less;

[0021] S2. placing a combined phased array ultrasonic probe at a specific position on the blade according to the detection process, and selecting a surface area of ​​the blade from the detection image to restore the surface contour of the blade within the coverage range of the probe sound beam;

[0022] S3, selecting a region to be inspected in the blade, and restoring the plane wave imaging signal in the region to be inspected inside the blade;

[0023] S4. Use an automatic or manual method to move the combined phased array ultrasonic probe along a predetermined process trajectory, and finally detect the blade root area to be inspected on the blade body.

[0024] Preferably, in step S3, if the inner curved surface of the blade root is detected, the combined phased array ultrasonic probe is placed on the outer curved surface of the blade body; if the outer curved surface of the blade root is detected, the combined phased array ultrasonic probe is placed on the inner curved surface of the blade body.

[0025] The beneficial effects of the present invention are:

[0026] 1. The present invention uses three independent parallel linear array array sub-probes to form a combined phased array ultrasonic probe, which avoids missed detection or rework of blade root defects caused by probe placement deviation during manual detection and installation deviation of the scanner probe clamping device during automatic detection.

[0027] 2. The detection process of the present invention is combined with the plane wave imaging function of the detection instrument to improve the imaging quality of the detection data and avoid missing the detection of tiny defects.

[0028] 3. This patent uses a flexible probe to reduce the impact of the coupling medium on the data detection quality during the detection process, thereby reducing the detection rework caused by the coupling quality of the detection data.

[0029] 4. The present invention utilizes simulation software to produce a detection process, thereby improving the reliability of detection, avoiding rework due to quality issues of detection data, and increasing detection speed.

[0030] 5. The combined phased array ultrasonic probe of the present invention has multiple usage modes, which improves the economy of the probe use. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of the sub-probe chip arrangement;

[0032] Figure 2 It is a schematic diagram of the structure of the middle sub-wedge in the length direction;

[0033] Figure 3 It is a schematic diagram of the structure of the middle sub-wedge in the width direction;

[0034] Figure 4 It is a schematic diagram of the structure of the sub-wedges on both sides in the length direction;

[0035] Figure 5 It is a schematic diagram of the structure of the sub-wedges on both sides in the width direction;

[0036] Figure 6It is a schematic diagram of the structure of a combined phased array ultrasonic wedge;

[0037] Figure 7 It is a schematic diagram of the structure in which the probe is installed on the wedge;

[0038] Figure 8 Schematic diagram of probe mode selection and splitter;

[0039] Fig. 9 This is a schematic diagram of the connection between the probe and the splitter;

[0040] Fig.10 Schematic diagram of the probe being placed on the blade.

[0041] Explanation of the reference numerals: first inclination angle 1, sound insulation material 2, flexible coupling layer 3, second inclination angle 4, third inclination angle 5, sub-probe 6, splitter 7, probe and instrument interface 8, combined phased array ultrasonic probe 9, combined button 10, independent button 11. DETAILED DESCRIPTION

[0042] The present invention is further described below in conjunction with embodiments. The description of the following embodiments is only used to help understand the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principles of the present invention, several improvements and modifications may be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0043] The fir-tree-shaped leaf root efficient detection device based on plane wave ultrasonic technology uses three independent parallel linear array array sub-probes to form a combined phased array ultrasonic probe. The recommended frequency of the probe is 7.5MHz. To improve the signal-to-noise ratio of the detection data, other frequencies can also be used. The number of chips in each linear array probe is 20, the spacing between two chips is 0.3mm, the width of the chip is 0.2mm, and the length of the chip is 5mm. The probe is connected to a splitter, and one end of the splitter pulls out the cables of three independent probes to connect the probes, and connects them to the probes through the interface. The other end is the main interface of the probe for connecting to the phased array ultrasonic instrument. An operation button is provided on the splitter to select the excitation type of the probe. There are two excitation modes of the probe, one mode is that the three probes are combined into a plane array arrangement of the probe for independent excitation, and the other mode is that the three sub-probes are excited as independent probes. During the detection process, it can be adjusted independently according to needs. This detection scheme uses three sub-probes as independent modes of independent probe excitation; the mode combined into a plane array arrangement needs to be used with other wedges, which is mainly used for other detection applications.

[0044] This patent also includes a combined phased array ultrasonic wedge that can be installed with three independent sub-probes at the same time. The bottom of the wedge adopts a semi-flexible structure. By injecting water at the bottom, the bottom of the wedge and the blade surface are closely fitted, thereby ensuring the coupling quality during the detection process. The combined phased array ultrasonic wedge is composed of three sub-wedges. The middle sub-wedge has an inclination angle in the length direction. The range of the inclination angle is generally between 36° and 39° according to the requirements of the blade specifications. The sub-wedges on both sides have an inclination angle in the length direction, and the size of the inclination angle is the same as that of the middle sub-wedge. The sub-wedges on both sides also have an angle in the width direction. The size of the angle is generally between 5° and 10°, and other angles can also be used according to the shape of the blade. The angles of the sub-wedges on both sides in the width direction are designed to be a mirror relationship. The structural advantage of the combined phased array ultrasonic wedge is that by combining the three wedges together, the effect of detecting the three sub-wedges before the combination can be achieved through one detection, which reduces the detection time and improves the detection efficiency. The inclination angles on the middle sub-wedge and the sub-wedges on both sides are used to generate oblique sound beams.

[0045] During the detection process, the instrument is programmed to stimulate different sub-probes in different time periods in a time-difference manner to carry out detection, and then finally through one scan, all three probes can detect the blade root area to be inspected from the blade body area.

[0046] During the inspection process, each sub-probe uses a detection solution based on plane wave imaging technology, combined with blade root surface adaptive imaging technology, to achieve accurate recognition of the blade root surface shape and rapid detection of the blade root area to be inspected. This scanning solution includes the following steps in implementation:

[0047] S1. Use simulation software to create the detection process, including the range of plane wave imaging, the location of the probe, the movement trajectory and other information during the detection; the imaging resolution is set to 0.5mm or less.

[0048] S2. Place the probe at a specific position on the blade according to the detection process, and select the surface area of ​​the blade from the detection image to restore the blade surface contour within the coverage of the probe sound beam.

[0049] S3, select the area to be inspected in the blade, and restore the plane wave imaging signal in the area to be inspected inside the blade; if the inner arc surface of the blade root is detected, the probe is generally placed on the outer arc surface of the blade body, and if the outer arc surface of the blade root is detected, the probe is generally placed on the inner arc surface of the blade body. The specific placement position is determined according to the blade structure using simulation software in step S1.

[0050] S4. Use an automatic or manual method to move the probe along a predetermined process trajectory, and finally detect the blade root area to be inspected on the blade body.

Claims

1. A fir-tree-shaped blade root high-efficiency detection device based on plane wave ultrasonic technology, characterized in that: The invention comprises a splitter (7), a combined phased array ultrasonic probe (9) and a combined phased array ultrasonic wedge; the combined phased array ultrasonic probe (9) is composed of three independent sub-probes arranged in a parallel linear array array; an interface at one end of the splitter (7) is connected to the combined phased array ultrasonic probe (9) via a cable, and a probe and instrument interface (8) is provided at the other end of the splitter (7), and the probe and instrument interface (8) is connected to the phased array ultrasonic instrument; the three sub-probes are installed on the combined phased array ultrasonic wedge, and the combined phased array ultrasonic wedge is composed of three sub-wedges, and each sub-probe corresponds to one sub-wedge; the bottom of the combined phased array ultrasonic wedge is provided with an injectable A flexible coupling layer (3) of water is provided, and the flexible coupling layer (3) is in contact with the blade curved surface; the sub-wedge in the middle of the combined phased array ultrasonic wedge is provided with a first tilt angle (1) in the length direction; the sub-wedges on both sides of the combined phased array ultrasonic wedge are provided with a second tilt angle (4) in the length direction, and the sub-wedges on both sides are also provided with a third tilt angle (5) in the width direction; one end of the splitter (7) is provided with three interfaces, which are respectively connected to three sub-probes of the combined phased array ultrasonic probe (9) through cables; the splitter (7) is provided with an operation button for selecting a probe excitation mode, and the operation button includes a combined button (10) and an independent button (11).

2. The fir-tree-shaped blade root efficient detection device based on plane wave ultrasonic technology according to claim 1 is characterized in that: The first inclination angle (1) and the second inclination angle (4) are the same, both being 36°-39°.

3. The fir-tree-shaped blade root efficient detection device based on plane wave ultrasonic technology according to claim 1 is characterized in that: The third inclination angle (5) is 5-10°.

4. The fir-tree-shaped blade root efficient detection device based on plane wave ultrasonic technology according to claim 1 is characterized in that: The angles of the sub-wedges on both sides of the combined phased array ultrasonic wedge are in a mirror image relationship in the width direction.

5. The fir-tree-shaped blade root efficient detection device based on plane wave ultrasonic technology according to claim 1 is characterized in that: The side of the sub-wedge in the middle of the combined phased array ultrasonic wedge is provided with a sound insulation material (2).

6. The fir-tree-shaped blade root efficient detection device based on plane wave ultrasonic technology according to claim 1 is characterized in that: The side parts of the sub-wedges on both sides of the combined phased array ultrasonic wedge are provided with sound insulation materials (2).

7. A detection method for a fir-tree-type blade root high-efficiency detection device based on plane wave ultrasonic technology as claimed in claim 1, characterized in that: The following steps are involved: S1. Use simulation software to create the detection process, including the range of plane wave imaging, the location of the probe and the trajectory of movement during detection; the imaging resolution is set to 0.5 mm or less; S2. placing a combined phased array ultrasonic probe at a specific position on the blade according to the detection process, and selecting a surface area of ​​the blade from the detection image to restore the surface contour of the blade within the coverage range of the probe sound beam; S3, selecting a region to be inspected in the blade, and restoring the plane wave imaging signal in the region to be inspected inside the blade; S4. Use an automatic or manual method to move the combined phased array ultrasonic probe along a predetermined process trajectory, and finally detect the blade root area to be inspected on the blade body.

8. The detection method of the fir-tree type blade root high-efficiency detection device based on plane wave ultrasonic technology according to claim 7 is characterized in that: In step S3, if the inner camber of the blade root is detected, the combined phased array ultrasonic probe is placed on the outer camber of the blade body; if the outer camber of the blade root is detected, the combined phased array ultrasonic probe is placed on the inner camber of the blade body.

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