A method for measuring conductivity of metal pipeline based on high-frequency eddy current

Abstract

The application provides a metal pipeline conductivity measurement method based on high-frequency eddy current, which comprises the following steps: designing an absolute eddy current sensor, arranging a sensor coil coaxially on the inner side of a metal pipeline, and generating eddy current by inputting high-frequency alternating current into the coil; establishing a simplified high-frequency eddy current detection analytical theory model, and setting the geometric size of the sensor and the pipeline; analyzing the relationship between the real part of the change of eddy current impedance under high-frequency excitation and the conductivity of the pipeline by using a Bessel function and a spatial resolution expression; setting the conductivity of the metal pipeline according to the analysis result, fitting the relationship between the change of impedance and the conductivity by using a power function; and inversely deriving the actual conductivity of the metal pipeline according to the measurement result of the coil impedance and the fitted power function curve. The application can effectively measure the conductivity of the metal pipeline.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electromagnetic eddy current for non-contact measurement of electromagnetic properties of metal pipes, and particularly relates to a metal pipe conductivity measurement method based on high-frequency eddy current. BACKGROUND

[0002] Metal pipes are widely used in the construction, petroleum and chemical industry, and power industry due to their superior strength, corrosion resistance, and good high-pressure resistance. However, metal pipes need to withstand various loads during service, especially under long-term service conditions, and their structures will be subjected to different degrees of stress and fatigue. Excessive stress can cause plastic deformation, cracks, and even failure of the metal pipe, thereby posing a serious threat to the safe operation of the system. Therefore, damage detection and performance evaluation of metal pipes under service conditions have important engineering significance.

[0003] The electromagnetic properties of metal pipes are closely related to their microstructure, chemical properties, and mechanical properties. For example, changes in the microstructure of the pipe will cause changes in electromagnetic parameters such as conductivity. By measuring the electromagnetic parameters of the metal pipe, the fatigue, defect, and other damage states of the pipe can be indirectly evaluated, thereby achieving non-destructive testing and condition monitoring. Based on this characteristic, using electromagnetic technology to detect metal pipes has become a research hotspot in the current non-destructive testing field.

[0004] Eddy current testing technology is a non-destructive testing method based on electromagnetic induction principle, and its core is to detect the changes of eddy current induced in the measured object, and then evaluate the electromagnetic properties such as conductivity and electrical conductivity of the measured object. Eddy current testing has the advantages of high sensitivity, fast detection speed, and non-contact measurement, and is particularly suitable for detecting defects, corrosion, fatigue, and conductivity of metal materials. In addition, eddy current testing can also achieve depth detection of metal materials of different thicknesses through the skin effect, and has a wide range of application scenarios.

[0005] Currently, the traditional eddy current testing method still has certain limitations in the application of metal pipe conductivity detection, such as insufficient detection accuracy and weak adaptability to complex working conditions. SUMMARY

[0006] The present application aims to at least partially solve one of the technical problems in the related art.

[0007] To this end, the first object of the present application is to provide a metal pipe conductivity measurement method based on high-frequency eddy current.

[0008] The second object of the present application is to provide a metal pipe conductivity measurement device based on high-frequency eddy current.

[0009] The third object of the present application is to provide an electronic device.

[0010] A fourth object of the present application is to provide a computer-readable storage medium.

[0011] A fifth object of the present application is to provide a computer program product.

[0012] To achieve the above objects, the first aspect of the present application provides a metal pipe conductivity measurement method based on high-frequency eddy current, comprising:

[0013] An absolute eddy current sensor is designed, the coil of the eddy current sensor is located on the inner side of the metal pipe and arranged coaxially with the metal pipe, an alternating high-frequency current is applied to the coil, so that the metal pipe generates eddy current;

[0014] A simplified metal pipe high-frequency eddy current detection analytical theory model is established, and the geometric dimensions of the coil and the metal pipe are set;

[0015] According to the characteristics of Bessel function and the spatial resolution expression, the relationship between the real part of the change in eddy current impedance under high-frequency excitation and the conductivity of the metal pipe is analyzed;

[0016] According to the analysis result, the conductivity of the metal pipe is set, and the set conductivity of the metal pipe is input into the simplified metal pipe high-frequency eddy current detection analytical theory model, and the relationship between the real part of the change in impedance and the conductivity is fitted by a power function;

[0017] According to the coil impedance measurement result, the actual conductivity of the metal pipe is obtained by inversion combined with the fitted power function curve.

[0018] Optionally, the geometric dimensions of the coil and the metal pipe include the inner diameter r1 of the coil, the outer diameter r2 of the coil, the height l2-l1 of the coil, the number of turns n of the coil, and the inner diameter a of the metal pipe.

[0019] Optionally, the calculation expression of the simplified metal pipe high-frequency eddy current detection analytical theory model includes an impedance amplitude term Z0 determined by the coil size and a phase term S(α0) determined by the electromagnetic properties and size of the metal pipe. Due to the presence of the metal pipe, the expression of the change in coil impedance ΔZ is:

[0020] ΔZ=S(α0)Z0

[0021] In the formula:

[0022]

[0023] In the formula, ω is the angular frequency of the excitation current, μ0 is the permeability, α0 is the spatial resolution, which is approximately calculated by the reciprocal of the average radius of the coil, I0 and I1 are the 0th and 1st order modified Bessel functions of the first kind, respectively, K0 and K1 are the 0th and 1st order modified Bessel functions of the second kind, respectively, and α1 is the complex-valued electromagnetic propagation constant.

[0024] Optionally, the step of analyzing the relationship between the real part of the eddy current impedance change and the conductivity of the metal pipe under high-frequency excitation based on the characteristics of the Bessel function and its spatial resolution expression includes:

[0025] When the excitation frequency reaches the MHz level, the following condition must be met:

[0026] αK1(α1a)I0(α0a)<<α1K0(α1a)I1(α0a)

[0027] and

[0028]

[0029] Substituting α1 into the coil impedance phase term S(α0), we obtain an approximate expression for the coil impedance phase term S(α0):

[0030]

[0031] At this point, the real part of the coil impedance change ΔZ is expressed as:

[0032]

[0033] Among them, the real part of the coil impedance change increases with the increase of the excitation frequency, and the real part of the impedance change has an inverse square root relationship with the conductivity σ of the metal pipe.

[0034] Optionally, the step of setting the conductivity of the metal pipe based on the analysis results and inputting the set conductivity of the metal pipe into the simplified analytical theoretical model for high-frequency eddy current detection of the metal pipe, and fitting the relationship between the real part of the impedance change and the conductivity through a power function, includes:

[0035] Based on the relationship between the real part of the eddy current impedance change and the conductivity of the metal pipe obtained from the analysis, multiple sets of metal pipe conductivity σ are set. i The real part of the impedance change ΔZ is calculated using the simplified analytical theoretical model for high-frequency eddy current detection of metal pipes. i ;

[0036] Determine the conductivity σ of a metal pipe i If the number of settings exceeds the threshold required for fitting, return to the previous step and reset the conductivity σ of the metal pipe. i ;

[0037] If yes, according to the impedance change real part expression, the power function y=kx is used -1 / 2 The impedance change real part real(ΔZ i ) is fitted with the metal pipeline conductivity σ.

[0038] Optionally, the actual conductivity of the metal pipeline is obtained by inversion according to the coil impedance measurement result combined with the fitted power function curve, including:

[0039] An actually measured coil impedance change real part value real(ΔZ) is obtained.

[0040] The measurement result is substituted into the fitted power function curve, and the actual conductivity of the metal pipeline is obtained by inversion through the formula k / (ΔZ 2 ).

[0041] To achieve the above purpose, the second aspect embodiment of the present application proposes a metal pipeline conductivity measurement device based on high-frequency eddy current, including:

[0042] An eddy current sensor design module is used to design an absolute eddy current sensor, the coil of the eddy current sensor is located on the inner side of the metal pipeline and arranged coaxially with the metal pipeline, high-frequency alternating current is applied to the coil, so that the metal pipeline generates eddy current;

[0043] An analytical theory modeling module is used to establish a simplified metal pipeline high-frequency eddy current detection analytical theory model, and the geometric sizes of the coil and the metal pipeline are set;

[0044] An impedance and conductivity analysis module is used to analyze the relationship between the high-frequency excitation eddy current impedance change real part and the metal pipeline conductivity according to the characteristics and spatial resolution expression of the Bessel function;

[0045] A conductivity fitting module is used to set the metal pipeline conductivity according to the analysis result, and input the set metal pipeline conductivity into the simplified metal pipeline high-frequency eddy current detection analytical theory model, and fit the impedance change real part and the conductivity by the power function;

[0046] A conductivity inversion module is used to obtain the actual conductivity of the metal pipeline by inversion according to the coil impedance measurement result combined with the fitted power function curve.

[0047] To achieve the above purpose, the third aspect embodiment of the present application proposes an electronic device, including a processor and a memory in communication connection with the processor;

[0048] The memory stores computer execution instructions;

[0049] The processor executes the computer execution instructions stored in the memory to realize the method in any one of the first aspect.

[0050] To achieve the above object, the fourth aspect of the present application provides a computer readable storage medium, wherein the computer readable storage medium stores computer execution instructions, and the computer execution instructions are executed by a processor to implement the method according to any one of the first aspect.

[0051] To achieve the above object, the fifth aspect of the present application provides a computer program product, wherein the computer program is executed by a processor to implement the method according to any one of the first aspect.

[0052] The technical scheme provided by the embodiments of the present application at least brings the following beneficial effects:

[0053] By combining the high-frequency eddy current detection technology with the analytical theoretical model and the mathematical fitting method, the relationship between the real part of the eddy current impedance change and the conductivity of the metal pipeline can be accurately established, the high-precision measurement of the conductivity of the metal pipeline is realized, and the whole detection process is designed as a non-contact type, without the need of directly contacting the surface of the metal pipeline, so that the damage to the pipeline surface caused by the traditional contact type measurement can be effectively avoided, and the non-destructive detection under various complex working conditions can be realized.

[0054] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0055] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, including the accompanying drawings, in which:

[0056] Figure 1 A flowchart of a metal pipeline conductivity measurement method based on high-frequency eddy current provided by the embodiments of the present application;

[0057] Figure 2 A configuration diagram of the inner coil and the metal member of the classical Dodd-Deeds eddy current analytical theoretical model provided by the embodiments of the present application;

[0058] Figure 3 A configuration diagram of the inner coil and the pipeline of the simplified metal pipeline high-frequency eddy current detection analytical theoretical model provided by the embodiments of the present application;

[0059] Figure 4 A comparison diagram of the calculation results of the simplified metal pipeline high-frequency eddy current detection analytical theoretical model and the original Dodd-Deeds theoretical model under the sweep mode provided by the embodiments of the present application;

[0060] Figure 5A schematic diagram of the relationship between the real part of the coil impedance change caused by the sample under different conductivities under 1MHz excitation and the conductivity provided by the embodiments of the present application.

[0061] Figure 6 A structural schematic diagram of a metal pipeline conductivity measurement device based on high-frequency eddy current provided by the embodiments of the present application. DETAILED DESCRIPTION

[0062] The embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the accompanying drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0063] In view of the problems existing in the prior art, the embodiments of the present application provide a metal pipeline conductivity measurement method based on high-frequency eddy current, Figure 1 A flowchart of a metal pipeline conductivity measurement method based on high-frequency eddy current provided by the embodiments of the present application. As shown in Figure 1 The method comprises the following steps:

[0064] S1, design an absolute eddy current sensor, the coil of the eddy current sensor is located on the inner side of the metal pipeline and arranged coaxially with the metal pipeline, and a high-frequency alternating current is passed through the coil to make the metal pipeline generate eddy current.

[0065] This step designs an absolute eddy current sensor for realizing high-frequency eddy current detection of the metal pipeline conductivity. Among them, the coil of the eddy current sensor is arranged on the inner side of the metal pipeline and arranged coaxially with the metal pipeline, so as to ensure the uniform distribution of the induced magnetic field and the sensitivity and stability of the detection. By passing a high-frequency alternating current through the coil, eddy current is induced on the surface of the metal pipeline, realizing non-contact measurement based on the principle of electromagnetic induction. In the specific design, the eddy current skin depth is much smaller than the pipe wall thickness, thereby enhancing the sensitivity and accuracy of the surface conductivity measurement.

[0066] Specifically, the eddy current sensor uses a sinusoidal alternating current to excite the coil, so that the copper metal pipeline inner surface generates eddy current, and by controlling the eddy current skin depth to be much smaller than the pipe wall thickness, the accuracy and stability of the surface conductivity measurement are effectively improved. In order to ensure the detection performance, the size and number of turns of the coil are accurately designed, wherein the inner diameter and outer diameter of the coil are 2mm and 5mm respectively, and the number of turns is 100. Such design can not only provide sufficient magnetic field strength, but also ensure the stability of the induced signal.

[0067] When eddy current is generated on the inner surface of the metal pipe, the secondary magnetic field is formed on the pipe surface. The strength and distribution of the secondary magnetic field are directly affected by the electromagnetic properties of the pipe conductivity. Subsequently, the secondary magnetic field generated by the eddy current is inducted and received by the coil, and the impedance change of the coil is determined by the strength of the induced eddy current. Since the strength of the eddy current is closely related to the conductivity of the pipe, this impedance change becomes an important detection parameter for evaluating the conductivity of the metal pipe.

[0068] Through the above design, this step not only realizes the efficient generation and reception of eddy current, but also provides high-precision impedance change data for subsequent analytical theory modeling and conductivity inversion. The entire detection process has the characteristics of non-contact, high sensitivity and high response speed, and is suitable for metal pipe detection in various industrial application scenarios.

[0069] S2, a simplified analytical theory model of high-frequency eddy current detection of metal pipe is established, and the geometric sizes of the coil and the metal pipe are set.

[0070] This step establishes a simplified analytical theory model of high-frequency eddy current detection of metal pipe, which is used to describe the relationship between the impedance change of the coil and the conductivity of the metal pipe. Based on the classical Dodd-Deeds eddy current analytical theory model, this step combines the actual detection conditions, and through hypothesis and simplification, the calculation efficiency of the model is significantly improved, while ensuring high calculation accuracy.

[0071] Figure 2 The configuration diagram of the coil and the metal member in the classical Dodd-Deeds eddy current analytical theory model is shown. The classical model assumes that the metal member is composed of two layers of structure, and the impedance change of the coil is calculated by the following formula:

[0072]

[0073] In the formula, S(α) and D(α) represent functions related to the coil parameters and the electromagnetic properties of the metal member, respectively, and the specific expressions are shown in the following formula:

[0074]

[0075] At this time, the two-layer structure of the metal pipe is represented by the inner radius a and the outer radius b, and the conductivities are σ1 and σ2, respectively.

[0076] When the excitation frequency reaches the order of MHz, due to the skin effect, the eddy current is concentrated on the surface of the metal pipe, which causes the double-layer structure characteristics of the metal pipe to be ignored, and thus simplified as a single-layer structure. Figure 3 The configuration diagram of the coil and the single-layer metal pipe in the simplified model is shown. Under the simplified conditions, it is assumed that σ1 = σ2 = σ, and b→∞, accordingly, S(α) and D(α) can be represented as:

[0077]

[0078] In addition, S(a) in the expression of ΔZ changes slowly compared with other integral variables, so it can be approximately extracted from the integral. Substituting S(a) and D(a) into ΔZ, we can get:

[0079] ΔZ = S(a0)Z0

[0080] where Z0 and S(a0) represent the impedance amplitude term determined by the coil size and the phase term determined by the electromagnetic properties and size of the metal pipe, respectively, and their specific expressions are as follows:

[0081]

[0082] where ω is the angular frequency of the excitation current, μ0 is the magnetic permeability, a0 is the spatial resolution, which is approximately calculated by the reciprocal of the average radius of the coil, I0 and I1 are the 0th and 1st order modified Bessel functions of the first kind, respectively, K0 and K1 are the 0th and 1st order modified Bessel functions of the second kind, respectively, and a1 is the complex-valued electromagnetic propagation constant.

[0083] In constructing the simplified analytical model of high-frequency eddy current testing of metal pipes, the geometric sizes of the coil and the metal pipe need to be set in the model, including the inner diameter of the coil r1, the outer diameter of the coil r2, the height of the coil l2-l1, the number of turns of the coil n, and the inner diameter of the metal pipe a.

[0084] To verify the effectiveness of the simplified model, the following parameters are set: the conductivity of the metal pipe is 58 MS / m, the inner and outer radii of the pipe are set to 6 mm and 8 mm, respectively, and the excitation frequency range is set to 1 kHz to 1 MHz. The calculation results of the simplified model are compared with those of the classic Dodd-Deeds model, as shown in Figure 4 In the entire frequency range, the maximum relative error of the two models is only 0.1%, and the calculation speed of the simplified model is improved by 19.9% compared with the classic model.

[0085] Through the above simplification, this step effectively reduces the computational complexity, provides fast and accurate theoretical support for real-time metal pipe conductivity detection, and at the same time ensures the accuracy and reliability of the high-frequency eddy current testing results.

[0086] S3, according to the characteristics of the Bessel function and the expression of the spatial resolution, analyze the relationship between the real part of the eddy current impedance change and the conductivity of the metal pipe under high-frequency excitation.

[0087] In the embodiments of the present application, based on the characteristics of the Bessel function and the spatial resolution expression, the relationship between the real part of the eddy current impedance change and the conductivity of the metal pipeline under high-frequency excitation is further analyzed. Through analytical derivation, the quantitative description of the real part of the coil impedance change to the conductivity of the metal pipeline is realized, which provides a theoretical basis for the subsequent fitting and inversion of the conductivity.

[0088] When the excitation frequency reaches the order of MHz, the eddy current is mainly distributed on the surface of the metal pipeline, and the following conditions are met:

[0089] αK1(α1a)I0(α0a)<<α1K0(α1a)I1(α0a)

[0090] And the complex electromagnetic propagation constant can be approximated as:

[0091]

[0092] Substituting the above conditions into the coil impedance phase term S(α0), the approximate expression of S(α0) can be obtained as:

[0093]

[0094] On this basis, the real part expression of the coil impedance change ΔZ is:

[0095]

[0096] As can be seen from the above formula, the real part of the coil impedance change is closely related to the excitation frequency and the conductivity of the metal pipeline, wherein: the real part of the impedance change increases with the increase of the excitation frequency ω, which indicates that high-frequency excitation can effectively enhance the detection sensitivity; and the real part of the impedance change is inversely proportional to the square root of the conductivity σ of the metal pipeline, that is:

[0097]

[0098] The physical meaning of the above relationship is that as the conductivity of the pipeline increases, the strength of the induced eddy current weakens, and the amplitude of the coil impedance change decreases. Through this negative correlation characteristic, the conductivity of the pipeline can be inverted by using the measured real part value of the impedance change.

[0099] In order to better verify the accuracy of the above formula, numerical calculation and analysis are carried out by using actual parameters in this step. Under the condition that the excitation frequency ranges from 1 kHz to 1 MHz, the calculation results show that the real part of the impedance change has a significant increasing trend in response to the excitation frequency, and the sensitivity of the real part of the impedance change to the conductivity of the metal pipeline conforms to the characteristics of the inverse square root relationship. This result verifies the reliability of the theoretical model, and provides a solid theoretical basis for the subsequent fitting of the conductivity.

[0100] Through the analysis of the above steps, the present application successfully constructs the quantitative relationship between the real part of impedance change and the conductivity of the metal pipeline, combines the characteristics of high-frequency excitation, provides theoretical support for realizing accurate conductivity measurement, and significantly improves the sensitivity and applicability of the detection system.

[0101] S4, setting the conductivity of the metal pipeline according to the analysis result, and inputting the set conductivity of the metal pipeline into the simplified metal pipeline high-frequency eddy current detection analytical theory model, and fitting the relationship between the real part of impedance change and the conductivity through a power function.

[0102] In the embodiment of the present application, based on the relationship between the real part of impedance change and the conductivity of the metal pipeline obtained by step S3, the mathematical relationship between the real part of impedance change and the conductivity is further fitted by setting different conductivity values of the metal pipeline and using the simplified metal pipeline high-frequency eddy current detection analytical theory model. Through the fitting of the power function relationship, a calculation method for quickly inverting the conductivity of the metal pipeline is established.

[0103] First, according to the relationship between the real part of eddy current impedance change and the conductivity of the metal pipeline under high-frequency excitation obtained by analysis, the conductivity σ i of the metal pipeline is set i .

[0104] Specifically, according to the actual detection requirements, the conductivity of the metal pipeline is set to be the value of a plurality of typical materials, including titanium alloy TC4 (0.56 MS / m), stainless steel 316L (2.32 MS / m), brass (15.9 MS / m), aluminum alloy (20 MS / m), aluminum (38 MS / m), and copper (58 MS / m), and then the simplified metal pipeline high-frequency eddy current detection analytical theory model is used to calculate the real part of the coil impedance change under the condition of 1 MHz excitation frequency.

[0105] Next, according to the calculation results of the simplified model, the conductivity σ i values of different materials and the corresponding real part of impedance change real(ΔZ) are input into the fitting program to fit the mathematical relationship between the real part of impedance change and the conductivity. In order to ensure the accuracy of the fitting result, different conductivity values real(ΔZ) of the metal pipeline are repeatedly set and the corresponding real part of impedance change is calculated, until the data quantity threshold required for fitting is met.

[0106] Once the conductivity data quantity required for fitting is met, according to the formula of the real part of impedance change in step S3, the power function y=kx -1 / 2 is used to fit the relationship between the real part of impedance change real(ΔZ i ) and the conductivity σ of the metal pipeline.

[0107] In one possible embodiment, the specific power function relationship obtained by fitting is:

[0108] real(ΔZ i )=11.76×σ i -0.5

[0109] The fitting result shows that there is a clear inverse square root relationship between the real part of the coil impedance change and the conductivity of the metal pipeline, and the correlation coefficient of the fitting is as high as 0.999, indicating that the fitting result has extremely high precision, and the calculation result is shown in Figure 5

[0110] By comparing the calculation results of different materials, it can be seen that as the conductivity of the metal pipeline increases, the real part of the coil impedance change presents a significant decreasing trend. This trend further verifies the inverse square root relationship in the theoretical formula, and also shows that the impedance change under high-frequency excitation has higher sensitivity to high-conductivity materials.

[0111] Through the fitting process of this step, the present application realizes high-precision mathematical description between the real part of the impedance change and the conductivity of the metal pipeline, and lays a data foundation for subsequent rapid inversion of the conductivity. The power function relationship obtained by fitting not only can significantly simplify the calculation process, but also has extremely high reliability, and is suitable for metal pipeline detection applications under various complex conditions.

[0112] S5, according to the coil impedance measurement result, combining the fitted power function curve, the actual conductivity of the metal pipeline is obtained by inversion.

[0113] In the embodiments of the present application, based on the power function relationship obtained by fitting in the foregoing steps, the actual conductivity of the metal pipeline is calculated by inversion combining the measured real part of the coil impedance change. Through this step, the complex conductivity calculation process can be simplified to rapid inversion operation based on measured data and fitting function, and efficient detection of the conductivity of the metal pipeline is realized.

[0114] In specific implementation, first, the measured real part of the coil impedance change real(ΔZ m is obtained, under experimental conditions, a high-frequency eddy current detection device is built, the excitation frequency is set to 1MHz, and eddy current excitation is applied to the metal pipeline. The measured real part of the coil impedance change ΔZ m caused by the metal pipeline reflects the conductivity of the pipeline material.

[0115] Subsequently, the measured real part of the coil impedance change ΔZ m is input into the aforementioned fitted power function relationship. Combining the fitting function real(ΔZ i )=11.76×σ i -0.5The actual electrical conductivity of the metal pipe is inverted. The inversion formula is:

[0116] σ=11.76 / (ΔZ m 2 )

[0117] This formula allows for the rapid and accurate conversion of actual measured values ​​into the conductivity of metal pipes. Taking a measurement experiment with an excitation frequency of 1MHz as an example, if the measured real part of the coil impedance change is ΔZ... m Substituting these values ​​into the above formula will directly yield the actual conductivity of the pipe.

[0118] In practical applications, this step, through the combination of impedance measurement and mathematical inversion, not only significantly improves the efficiency of conductivity calculation but also ensures the reliability and accuracy of the results. Experimental verification shows that, using the detection method and device of this invention, the relative error between the measured conductivity value of metal pipes and the standard value is controlled within 0.5%, which can meet the high-precision detection requirements of engineering applications.

[0119] In summary, this step combines measured data from eddy current testing with a fitted mathematical model, successfully achieving the inversion calculation from the real part of impedance change to conductivity, further validating the operability and practical application value of this application. The accurate conductivity inversion results can provide a scientific basis for the health status assessment and performance analysis of metal pipelines, while also offering significant advantages in terms of high sensitivity and rapid response.

[0120] To achieve the above embodiments, this application also proposes a metal pipe conductivity measuring device based on high-frequency eddy currents. Figure 6 This is a schematic diagram of a metal pipe conductivity measuring device based on high-frequency eddy currents, provided as an embodiment of this application. Figure 6 As shown, the device includes:

[0121] Eddy current sensor design module 100 is used to design an absolute eddy current sensor. The coil of the eddy current sensor is located inside the metal pipe and is arranged coaxially with the metal pipe. A high-frequency alternating current is passed through the coil to generate eddy currents in the metal pipe.

[0122] The analytical theory modeling module 200 is used to establish a simplified analytical theory model for high-frequency eddy current detection of metal pipes and to set the geometric dimensions of the coil and the metal pipe.

[0123] Impedance and conductivity analysis module 300 is used to analyze the relationship between the real part of the eddy current impedance change and the conductivity of the metal pipe under high-frequency excitation, based on the characteristics of the Bessel function and the spatial resolution expression.

[0124] The conductivity fitting module 400 is configured to set the conductivity of the metal pipeline according to the analysis result, and input the set conductivity of the metal pipeline into the simplified metal pipeline high-frequency eddy current detection analytical theory model, and fit the relationship between the real part of the impedance change and the conductivity by using a power function.

[0125] The conductivity inversion module 500 is configured to inversely obtain the actual conductivity of the metal pipeline according to the coil impedance measurement result and in combination with the fitted power function curve.

[0126] In order to realize the above-mentioned embodiments, the present application further provides an electronic device, comprising a processor and a memory connected with the processor in communication; the memory stores computer execution instructions; and the processor executes the computer execution instructions stored in the memory to realize the method provided by the foregoing embodiments.

[0127] In order to realize the above-mentioned embodiments, the present application further provides a computer readable storage medium, wherein the computer readable storage medium stores computer execution instructions, and the computer execution instructions are executed by a processor to realize the method provided by the foregoing embodiments.

[0128] In order to realize the above-mentioned embodiments, the present application further provides a computer program product, comprising a computer program, and the computer program is executed by a processor to realize the method provided by the foregoing embodiments.

[0129] The collection, storage, use, processing, transmission, provision and disclosure of the personal information of the user involved in the present application comply with the relevant laws and regulations, and do not violate public order and good customs.

[0130] It should be noted that the personal information from the user should be collected for legal and reasonable purposes, and should not be shared or sold outside these legal uses. In addition, such collection / sharing should be carried out after the user's informed consent is received, including but not limited to informing the user to read the user agreement / user notice before the user uses the function, and signing the agreement / authorization including authorization of relevant user information. In addition, any necessary steps should be taken to protect and ensure access to such personal information data, and to ensure that other people with access to personal information data comply with their privacy policy and processes.

[0131] The present application is expected to provide an embodiment in which the user can selectively prevent the use or access of personal information data. That is, the present disclosure is expected to provide hardware and / or software to prevent or prevent access to such personal information data. Once the personal information data is no longer needed, the risk is minimized by limiting data collection and deleting data. In addition, such personal information is de-identified to protect the privacy of the user, if applicable.

[0132] In the foregoing detailed description, reference is made to descriptive terms such as "one embodiment", "some embodiments", "an example", "a specific example" or "some examples" etc. for describing various embodiments of the application. These descriptive terms are used for the purpose of the description and are not meant to limit or restrict the scope of the application. The use of these terms does not imply that the application is comprised of at least the features described in the specific example. In addition, the description is not meant to imply that the described embodiments are the only manner in which the application can be practiced. Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments or examples. Moreover, the described embodiments and features are not meant to be all inclusive but rather are meant to be exemplary only. Furthermore, those skilled in the art will recognize that the described embodiments and features can be combined with other embodiments and features in a suitable manner without departing from the scope of the application.

[0133] In addition, the terms "first", "second", etc. are used herein only to describe various embodiments and do not imply either a relative importance or an implicit indication that the described features are limited to a quantity of two. Thus, a feature defined with "first" or "second" can implicitly or explicitly include at least one of the feature. In the description of the application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise expressly specified.

[0134] Any process or method descriptions or blocks in flow charts or otherwise described herein represent embodiments of the application that can be managed as one or more modules, segments, or portions of code that include one or more steps for implementing specific logic functions or steps, and the various embodiments of the application can include additional or fewer steps performing the same or equivalent functions. In some embodiments, the blocks can be combined into a software or firmware routine.

[0135] The logic and / or steps represented in the flowcharts and / or described herein, for example, can be considered as a sequence of executable instructions stored in a computer readable medium, which can be executed by an instruction execution system, apparatus or device, such as a computer-based system, a processor-based system, or other system that can fetch the instructions from the instruction execution system, apparatus or device and execute the instructions, or a combination of them. For the purposes of this specification, a "computer readable medium" can be any apparatus that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus or device. The computer readable medium can be a computer readable storage medium or a computer readable signal medium. The computer readable storage medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, a portable computer diskette (magnetic), a RAM (random access memory), a ROM (read only memory), an EPROM (erasable programmable ROM), EEPROM (electrically erasable programmable ROM), a storage

[0136] It should be understood that aspects of the application can be implemented in hardware, software, firmware or a combination thereof. In the above embodiments, various steps or methods can be implemented in software or firmware that is stored in memory and executed by a suitable instruction execution system. As such, in some embodiments, specifically configured hardware can be used to implement at least some of the functionality described herein. In another embodiment, software or firmware can be used to implement at least some of the functionality described herein, which would be processed by a general purpose instruction computer or other processing system. Specifically, any of the following can be used to implement one or both of the above described embodiments: discrete logic circuitry having logic gates for implementing logic functions upon data signals, application specific integrated circuits having logic gates, field programmable gate arrays (FPGA), or other implementations.

[0137] Those of skill in the art would understand that information and signals can be represented using any of a variety of technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that can be referenced throughout the above description can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0138] In addition, each of the function units in each embodiment of the present application can be integrated in one processing module, or each unit can be physically present separately, or two or more units can be integrated in one module. The integrated module can be realized in the form of hardware or in the form of a software function module. When the integrated module is realized in the form of a software function module and sold or used as an independent product, it can also be stored in a computer readable storage medium.

[0139] The storage medium mentioned above can be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

[0140] It should be understood that the various forms of flow shown above can be reordered, added or deleted steps. For example, each step described in the present application can be executed in parallel, sequentially or in different order, as long as the desired results of the technical solutions of the present application can be achieved, which is not limited herein.

[0141] The above detailed description does not constitute a limitation on the scope of protection of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations and replacements can be made according to design requirements and other factors. Any modifications, equivalent replacements and improvements within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A method for measuring the conductivity of metal pipes based on high-frequency eddy currents, characterized in that, Includes the following steps: Design an absolute eddy current sensor, wherein the coil of the eddy current sensor is located inside the metal pipe and arranged coaxially with the metal pipe, and a high-frequency alternating current is passed through the coil to generate eddy currents in the metal pipe. A simplified analytical theoretical model for high-frequency eddy current detection of metal pipes is established, and the geometric dimensions of the coil and the metal pipe are set. Based on the characteristics and spatial resolution expression of the Bessel function, the relationship between the real part of the eddy current impedance change and the conductivity of the metal pipe under high-frequency excitation is analyzed. Based on the analysis results, the conductivity of the metal pipe is set, and the set conductivity of the metal pipe is input into the simplified analytical theoretical model for high-frequency eddy current detection of the metal pipe. The relationship between the real part of the impedance change and the conductivity is fitted by a power function. Based on the coil impedance measurement results and the fitted power function curve, the actual conductivity of the metal pipe is obtained by inversion. The geometric dimensions of the coil and the metal conduit include: the inner diameter of the coil. outer diameter of the coil Coil height Number of coil turns With the inner diameter of the metal pipe ; The calculation expression of the simplified analytical theoretical model for high-frequency eddy current detection of metal pipes includes an impedance amplitude term determined by the coil size. Phase term determined by the electromagnetic properties and dimensions of the metal pipe Due to the presence of the metal pipe, the coil impedance changes. The expression is: In the formula: In the formula, Let ω be the angular frequency of the excitation current. Permeability, For spatial resolution, it is approximated by the reciprocal of the average radius of the coil. and These are the 0th and 1st order modified Bessel functions of the first kind, respectively. and These are the 0th and 1st order modified Bessel functions of the second kind, respectively. The electromagnetic propagation constant is a complex value. The conductivity of the metal pipe.

2. The method according to claim 1, wherein analyzing the relationship between the real part of the eddy current impedance change and the conductivity of the metal pipe under high-frequency excitation based on the characteristics of the Bessel function and the spatial resolution expression includes: When the excitation frequency reaches the MHz level, the following condition must be met: and Will Substitute the coil impedance phase term The coil impedance phase term is obtained. The approximate expression is: At this time, the coil impedance changes The real part expression is: The real part of the coil impedance change increases with increasing excitation frequency, and the real part of the impedance change is related to the conductivity of the metal pipe. They form an inverse square root relationship.

3. The method according to claim 2, characterized in that, The process involves setting the conductivity of the metal pipe based on the analysis results, inputting the set conductivity into the simplified analytical theoretical model for high-frequency eddy current detection of the metal pipe, and fitting the relationship between the real part of the impedance change and the conductivity using a power function. This includes: Based on the relationship between the real part of the eddy current impedance change and the conductivity of the metal pipe obtained from the analysis, the conductivity of the metal pipe is set... The real part of the impedance change was calculated using the simplified analytical theoretical model for high-frequency eddy current detection of metal pipes. ; Determining the conductivity of metal pipes If the number of settings exceeds the threshold required for fitting, return to the previous step and reset the conductivity of the metal pipe. ; If satisfied, then the power function is used based on the expression for the real part of the impedance change. The real part of the fitted impedance change With the electrical conductivity of metal pipes The relationship.

4. The method according to claim 3, characterized in that, The actual conductivity of the metal pipe is obtained by inverting the measurement results of the coil impedance and combining them with the fitted power function curve, including: Obtain the real part of the actual measured coil impedance change. ; Substitute the measurement results into the fitted power function curve, and use the formula... The actual electrical conductivity of the metal pipe is obtained through inversion.

5. A device for measuring the conductivity of metal pipes based on high-frequency eddy currents, characterized in that, include: Eddy current sensor design module, used to design absolute eddy current sensors, wherein the coil of the eddy current sensor is located inside the metal pipe and arranged coaxially with the metal pipe, and a high-frequency alternating current is passed through the coil to generate eddy currents in the metal pipe. The analytical theory modeling module is used to establish a simplified analytical theory model for high-frequency eddy current detection of metal pipes and to set the geometric dimensions of the coil and the metal pipe. The impedance and conductivity analysis module is used to analyze the relationship between the real part of the eddy current impedance change and the conductivity of the metal pipe under high-frequency excitation, based on the characteristics of the Bessel function and the spatial resolution expression. The conductivity fitting module is used to set the conductivity of the metal pipe according to the analysis results, and input the set conductivity of the metal pipe into the simplified analytical theoretical model for high-frequency eddy current detection of the metal pipe, and fit the relationship between the real part of the impedance change and the conductivity through a power function. The conductivity inversion module is used to invert the actual conductivity of the metal pipe based on the coil impedance measurement results and the fitted power function curve. The geometric dimensions of the coil and the metal conduit include: the inner diameter of the coil. outer diameter of the coil Coil height Number of coil turns With the inner diameter of the metal pipe ; The calculation expression of the simplified analytical theoretical model for high-frequency eddy current detection of metal pipes includes an impedance amplitude term determined by the coil size. Phase term determined by the electromagnetic properties and dimensions of the metal pipe Due to the presence of the metal pipe, the coil impedance changes. The expression is: In the formula: In the formula, Let ω be the angular frequency of the excitation current. Permeability, For spatial resolution, it is approximated by the reciprocal of the average radius of the coil. and These are the 0th and 1st order modified Bessel functions of the first kind, respectively. and These are the 0th and 1st order modified Bessel functions of the second kind, respectively. The electromagnetic propagation constant is a complex value. The conductivity of the metal pipe.

6. An electronic device, characterized in that, include: A processor, and a memory communicatively connected to the processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory to implement the method as described in any one of claims 1-4.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the method as described in any one of claims 1-4.

8. A computer program product, characterized in that, Includes a computer program that, when executed by a processor, implements the method of any one of claims 1-4.

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