Lamb wave-based pipeline liquid level detection method, system, equipment and medium

Abstract

This invention relates to the field of pipeline inspection, providing a method, system, equipment, and medium for pipeline liquid level detection based on Lamb waves. The method includes selecting an installation location and installing a Lamb wave sensor at that location; determining the excitation period and frequency, calculating the excitation angle, and driving an ultrasonic probe to generate an initial Lamb wave; the Lamb wave sensor measuring the initial signal generated by the initial Lamb wave; selecting a window function, weighting the initial signal to obtain a windowed signal, and performing wavelet transform to obtain a denoised signal; performing Hilbert-Huang transform to obtain multiple first transform signals, sequentially performing Hilbert transform to obtain the instantaneous frequency, adjusting the initial Lamb wave to obtain the target Lamb wave; calculating the attenuation coefficient and constructing a fitting formula; transmitting the target Lamb wave and detecting it through the Lamb wave sensor to obtain a detection signal; and detecting the liquid level height in the target pipeline. This invention can detect the liquid level height of accumulated liquid in pipelines.

Description

Technical Field

[0001] This invention relates to the field of pipeline inspection technology, and in particular to pipeline liquid level detection methods, systems, equipment and media based on Lamb waves. Background Technology

[0002] Ensuring the safety and stability of long-distance oil and gas gathering and transportation pipelines is crucial for the smooth and efficient delivery of oil and gas resources to their destinations. The core of this is ensuring the normal flow status of the pipelines. Due to the influence of the natural environment, temperature and pressure differences during pipeline transportation can affect the saturated water content per unit volume of the gas, easily leading to liquefaction and gas-liquid separation. Condensed water can form liquid seals at bends and the bottom of inclined sections of the gathering and transportation pipeline, reducing the effective flow area. In winter, pipelines are prone to freezing, causing complete blockage and halting transportation. Therefore, researching and developing effective flow status detection technologies for gathering and transportation pipelines, addressing the liquefaction, freezing, and corrosion problems that commonly occur in deeply buried pipelines under complex industrial conditions, is of profound significance for ensuring the safe operation of gathering and transportation pipelines and the efficient utilization of oil and gas resources. This is a pressing issue that needs to be addressed in the application of long-distance oil and gas gathering and transportation pipelines.

[0003] Compared with traditional ultrasonic detection methods, Lamb wave measurement is more robust to liquid level fluctuations and is less affected by fluctuating liquid surfaces. Research on Lamb wave liquid level measurement technology has been conducted both domestically and internationally; however, most studies focus on the propagation of Lamb waves in flat plates. For example, a two-dimensional finite element model was developed to simulate the propagation of Lamb waves in empty and water-filled containers. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in related technologies. To this end, this invention provides a method, system, equipment, and medium for pipeline liquid level detection based on Lamb waves, enabling rapid and non-destructive detection of the liquid level height in pipelines.

[0005] This invention provides a pipeline liquid level detection method based on Lamb waves, comprising:

[0006] S1: Select the target pipe, select an installation position on the target pipe, and install the Lamb wave sensor at the installation position;

[0007] S2: Determine the excitation period and excitation frequency, calculate the excitation angle, and drive the ultrasonic probe to generate an initial Lamb wave based on the excitation period, excitation frequency and excitation angle. The Lamb wave sensor measures the initial signal generated by the initial Lamb wave.

[0008] S3: Select a window function, weight the initial signal using the window function to obtain a windowed signal, and perform wavelet transform on the windowed signal to obtain a denoised signal;

[0009] S4: Perform Hilbert-Huang transform on the denoised signal to obtain multiple first transformed signals. Perform Hilbert transform on each first transformed signal in sequence to obtain multiple second transformed signals. Obtain the instantaneous frequency of the second transformed signal. Adjust the initial Lamb wave according to the instantaneous frequency to obtain the target Lamb wave.

[0010] S5: Calculate the attenuation coefficient of the target pipe, construct a fitting formula for the liquid level height and the detection signal using the attenuation coefficient, emit the target Lamb wave and detect it using the Lamb wave sensor to obtain the detection signal, and use the fitting formula and the detection signal to detect the liquid level height in the target pipe.

[0011] According to the pipeline liquid level detection method based on Lamb wave provided by the present invention, step S1 further includes:

[0012] S11: Select the target pipeline, determine the installation interval, and select installation positions at the upper and lower parts of the target pipeline according to the installation interval;

[0013] S12: Install the Lamb wave sensor at the installation position, and the side of the Lamb wave sensor that is in contact with the target pipe is arc-shaped.

[0014] According to the pipeline liquid level detection method based on Lamb wave provided by the present invention, step S2 further includes:

[0015] S21: Select an excitation mode, and determine the excitation period and the excitation frequency based on the excitation mode;

[0016] S22: Select an ultrasonic probe, determine the phase velocity of the excitation mode and the sound wave propagation velocity of the ultrasonic probe, and calculate the excitation angle using the sound wave propagation velocity and the phase velocity;

[0017] S23: Using the excitation angle as the probe angle of the ultrasonic probe, the ultrasonic probe is used to generate an initial Lamb wave according to the excitation period and excitation frequency, and the Lamb wave sensor measures the initial signal generated by the initial Lamb wave.

[0018] According to the Lamb wave-based pipeline level detection method provided by the present invention, the excitation mode is a longitudinal guiding mode.

[0019] According to the pipeline liquid level detection method based on Lamb wave provided by the present invention, step S3 further includes:

[0020] S31: Select the Hanning window as the window function, and weight the initial signal using the window function to obtain the windowed signal;

[0021] S32: The windowed signal is discretized by scale and time axis to obtain a discrete signal. The wavelet basis type and wavelet decomposition level are selected. The discrete signal is decomposed by wavelet according to the wavelet basis type and wavelet decomposition level to obtain wavelet coefficients and wavelet signal.

[0022] S33: Threshold quantization is performed on the wavelet coefficients to obtain quantization coefficients, and wavelet reconstruction is performed on the wavelet signal using the quantization coefficients to obtain the denoised signal.

[0023] According to the pipeline liquid level detection method based on Lamb wave provided by the present invention, step S4 further includes:

[0024] S41: Calculate the local maxima and local minima of the denoised signal, use the local maxima and cubic spline interpolation to obtain the fitted upper envelope, and use the local minima and cubic spline interpolation to obtain the fitted lower envelope.

[0025] S42: Obtain the mean envelope by fitting the upper envelope and the lower envelope, calculate the difference between the denoised signal and the mean envelope, and obtain the first transformed signal;

[0026] S43: Define the transformation completion condition, determine whether the first transformed signal meets the transformation completion condition, and when the first transformed signal does not meet the transformation completion condition, use the obtained first transformed signal as the denoised signal and repeat steps S41 to S42 until the first transformed signal meets the transformation completion condition, thereby obtaining multiple first transformed signals;

[0027] S44: Perform Hilbert transform on each first transformed signal in sequence to obtain multiple second transformed signals, obtain the second signal phase of the second transformed signal, differentiate the second signal phase to obtain the instantaneous frequency of the second transformed signal, adjust the initial Lamb wave according to the instantaneous frequency to obtain the target Lamb wave.

[0028] According to the pipeline liquid level detection method based on Lamb wave provided by the present invention, step S5 further includes:

[0029] S51: Determine the liquid properties of the liquid in the target pipe and the pipe material of the target pipe, and calculate the attenuation coefficient of the target pipe based on the liquid properties and pipe material;

[0030] S52: Determine the fitting coefficient of the target pipeline, and construct the fitting formula for the liquid level height and the detection signal based on the fitting coefficient and the attenuation coefficient;

[0031] S53: The target Lamb wave is emitted and detected by the Lamb wave sensor. A Fourier transform is performed to obtain the detection signal. The liquid level height in the target pipe is calculated using the fitting formula and the detection signal.

[0032] This invention also provides a pipeline liquid level detection system based on Lamb waves, comprising:

[0033] Equipment installation module: used to select the target pipeline, select the installation position on the target pipeline, and install the Lamb wave sensor at the installation position;

[0034] Initial signal module: used to determine the excitation period and excitation frequency, calculate the excitation angle, drive the ultrasonic probe to generate an initial Lamb wave based on the excitation period, excitation frequency and excitation angle, and the Lamb wave sensor measures the initial signal generated by the initial Lamb wave;

[0035] Denoising signal module: used to select a window function, weight the initial signal through the window function to obtain a windowed signal, and perform wavelet transform on the windowed signal to obtain a denoised signal;

[0036] Lamb wave adjustment module: used to perform Hilbert-Huang transform on the denoised signal to obtain multiple first transformed signals, perform Hilbert transform on each first transformed signal in sequence to obtain multiple second transformed signals, obtain the instantaneous frequency of the second transformed signal, and adjust the initial Lamb wave according to the instantaneous frequency to obtain the target Lamb wave;

[0037] Liquid level detection module: used to calculate the attenuation coefficient of the target pipe, construct a fitting formula between the liquid level and the detection signal based on the attenuation coefficient, emit a target Lamb wave and detect it through a Lamb wave sensor to obtain a detection signal, and use the fitting formula and the detection signal to detect the liquid level in the target pipe.

[0038] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the Lamb wave-based pipeline liquid level detection method described above.

[0039] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the Lamb wave-based pipeline liquid level detection method as described above.

[0040] The above-described one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects:

[0041] The present invention provides a method, system, device and medium for detecting pipeline liquid level based on Lamb wave. It generates Lamb wave by ultrasonic probe and adjusts the Lamb wave to generate a specific mode of Lamb wave. The liquid level in the pipeline can be deduced from the amplitude energy of the received Lamb wave, so as to provide timely and effective early warning of liquid accumulation in the pipeline and reduce the losses caused by pipeline blockage.

[0042] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0044] Figure 1 This is a schematic flowchart of the pipeline liquid level detection method based on Lamb wave provided by the present invention.

[0045] Figure 2 This is a comparison diagram of the signal amplitude of the detection signal under empty pipe and liquid accumulation conditions for the pipeline liquid level detection method based on Lamb wave provided by the present invention.

[0046] Figure 3 This is a comparison chart of the theoretical and measured values ​​of the amplitude energy versus liquid level curve of the pipeline liquid level detection method based on Lamb wave provided by this invention.

[0047] Figure 4 This is a schematic diagram of the pipeline liquid level detection system based on Lamb waves provided by the present invention.

[0048] Figure 5 This is a schematic diagram of the structure of the pipeline liquid level detection device based on Lamb wave provided by the present invention.

[0049] Figure label:

[0050] 100. Equipment installation module; 200. Initial signal module; 300. Noise reduction signal module; 400. Lamb wave adjustment module; 500. Liquid level detection module; 810. Processor; 820. Communication interface; 830. Memory; 840. Communication bus. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention. The following embodiments are used to illustrate this invention but cannot be used to limit the scope of this invention.

[0052] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0053] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0054] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0055] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0056] The following combination Figures 1 to 5 Specific embodiments of the present invention are described below:

[0057] Figure 1 This is a schematic flowchart of the pipeline liquid level detection method based on Lamb waves provided by the present invention. First, a target pipeline is selected, and an installation position is chosen on the target pipeline. The Lamb wave sensor is then installed at the installation position. Next, another target pipeline is selected, and the installation position is chosen on the target pipeline. The Lamb wave sensor is then installed at the installation position. Subsequently, a window function is selected, and the initial signal is weighted using the window function to obtain a windowed signal. A wavelet transform is performed on the windowed signal to obtain a denoised signal. Then, a Hilbert-Huang transform is performed on the denoised signal to obtain multiple first-transformed signals. Each first-transformed signal is then sequentially subjected to a Hilbert transform to obtain multiple second-transformed signals. The instantaneous frequency of the second-transformed signals is obtained, and the initial Lamb wave is adjusted according to the instantaneous frequency to obtain the target Lamb wave. Finally, the attenuation coefficient of the target pipeline is calculated, and a fitting formula for the liquid level height and the detection signal is constructed using the attenuation coefficient. The target Lamb wave is emitted and detected by the Lamb wave sensor to obtain a detection signal. The fitting formula and the detection signal are then used to detect the liquid level height in the target pipeline.

[0058] This invention provides a pipeline liquid level detection method based on Lamb waves, specifically including:

[0059] S1: Select the target pipe, select an installation position on the target pipe, and install the Lamb wave sensor at the installation position;

[0060] Furthermore, the objective of this stage is to install the Lamb wave sensor at the aforementioned mounting location. Specifically, step S1 further includes:

[0061] S11: Select the target pipeline, determine the installation interval, and select installation positions at the upper and lower parts of the target pipeline according to the installation interval;

[0062] S12: Install the Lamb wave sensor at the installation position, and the side of the Lamb wave sensor that is in contact with the target pipe is arc-shaped.

[0063] The specific implementation method for the above steps in this embodiment is as follows:

[0064] First, a section of the gas pipeline to be measured needs to be selected as the target pipeline. Then, based on experience, a reasonable spacing of the Lamb wave sensors is selected as the installation interval. A smaller installation interval results in higher detection accuracy, but requires a larger number of Lamb wave sensors, thus increasing costs. An excessively large installation interval can measure the liquid level in a longer target pipeline, but measurement accuracy cannot be guaranteed. Since the Lamb wave propagates in a spiral manner within the target pipeline, installation positions must be selected at both the upper and lower parts of the target pipeline according to the installation interval.

[0065] The Lamb wave sensor is then installed at the designated location. Since most target pipes are buried underground, the outer shell of the Lamb wave sensor is made of corrosion-resistant, rust-resistant, and high-temperature-resistant stainless steel. Furthermore, to ensure a tight fit between the sensor and the target pipe for optimal detection, the side of the Lamb wave sensor that contacts the target pipe must be rounded.

[0066] S2: Determine the excitation period and excitation frequency, calculate the excitation angle, and drive the ultrasonic probe to generate an initial Lamb wave based on the excitation period, excitation frequency and excitation angle. The Lamb wave sensor measures the initial signal generated by the initial Lamb wave.

[0067] Furthermore, the objective of this stage is to calculate the excitation angle to drive the ultrasonic probe to generate an initial Lamb wave, and to enable the Lamb wave sensor to measure the initial signal. Specifically, step S2 further includes:

[0068] S21: Select an excitation mode, and determine the excitation period and the excitation frequency based on the excitation mode;

[0069] S22: Select an ultrasonic probe, determine the phase velocity of the excitation mode and the sound wave propagation velocity of the ultrasonic probe, and calculate the excitation angle using the sound wave propagation velocity and the phase velocity;

[0070] S23: Using the excitation angle as the probe angle of the ultrasonic probe, the ultrasonic probe is used to generate an initial Lamb wave according to the excitation period and excitation frequency, and the Lamb wave sensor measures the initial signal generated by the initial Lamb wave.

[0071] The excitation mode is a longitudinal broadcast mode.

[0072] The specific implementation method for the above steps in this embodiment is as follows:

[0073] First, an excitation mode needs to be selected. Here, the selected excitation mode is the longitudinal conduction mode, i.e., L(0,1). This is because when the pipe contains liquid, the longitudinal conduction mode will experience a large amount of energy leakage, making it highly sensitive to liquid accumulation in the pipe. Here, L represents longitudinal conduction, 0 represents that the excitation mode is axisymmetric, and 1 represents that one wavelength contains one half-wave. The excitation period and excitation frequency are determined based on the excitation mode. In this embodiment, the target pipe is made of carbon steel, the excitation frequency is 200kHz, and the excitation period is 3 periods.

[0074] First, an ultrasonic probe needs to be selected. The ultrasonic probe can be used to excite and generate Lamb waves. Then, the phase velocity of the excitation mode is determined based on the material of the target pipe and the ultrasonic probe. and the sound wave propagation speed of the ultrasonic probe The excitation angle θ is then calculated using the sound wave propagation speed and phase velocity.

[0075]

[0076] The excitation angle is then used as the probe angle of the ultrasonic probe, which generates an initial Lamb wave based on the excitation period and frequency. Ideally, when the Lamb wave is incident on the planar interface at a certain angle, reflection and refraction of transverse and longitudinal waves occur, resulting in the initial Lamb wave having a refraction angle of 90 degrees. This allows it to propagate forward along the direction parallel to the pipe wall and be measured by the Lamb wave sensor to obtain the initial signal.

[0077] S3: Select a window function, weight the initial signal using the window function to obtain a windowed signal, and perform wavelet transform on the windowed signal to obtain a denoised signal;

[0078] Furthermore, the objective of this stage is to address the spectral leakage problem of the initial signal through a window function and to denoise the initial signal using wavelet transform. Specifically, step S3 further includes:

[0079] S31: Select the Hanning window as the window function, and weight the initial signal using the window function to obtain the windowed signal;

[0080] S32: The windowed signal is discretized by scale and time axis to obtain a discrete signal. The wavelet basis type and wavelet decomposition level are selected. The discrete signal is decomposed by wavelet according to the wavelet basis type and wavelet decomposition level to obtain wavelet coefficients and wavelet signal.

[0081] S33: Threshold quantization is performed on the wavelet coefficients to obtain quantization coefficients, and wavelet reconstruction is performed on the wavelet signal using the quantization coefficients to obtain the denoised signal.

[0082] The specific implementation method for the above steps in this embodiment is as follows:

[0083] Because real-world measurement environments contain numerous sources of interference and error compared to theoretical conditions, the initial Lamb wave calculated theoretically may not achieve the desired effect. Therefore, adjustments to the initial Lamb wave are necessary. First, a window function needs to be selected; here, the Hanning window is chosen. The initial signal is weighted using the Hanning window, which reduces spectral leakage, resulting in a windowed signal. Subsequently, the windowed signal is discretized sequentially by scale and time axis to obtain a discrete signal. Next, the wavelet basis type and the wavelet decomposition level N are selected, and the discrete signal is decomposed N times according to the wavelet basis type to obtain the wavelet coefficients and wavelet signals at each level.

[0084] Next, threshold quantization is performed on the wavelet coefficients. That is, hard threshold quantization or soft threshold quantization is used to quantize the high-frequency wavelet coefficients in the wavelet coefficients using a quantization threshold selected based on experience, and quantization coefficients are obtained. Finally, wavelet reconstruction is performed on the wavelet signal using the quantization coefficients to obtain the denoised signal.

[0085] S4: Perform Hilbert-Huang transform on the denoised signal to obtain multiple first transformed signals. Perform Hilbert transform on each first transformed signal in sequence to obtain multiple second transformed signals. Obtain the instantaneous frequency of the second transformed signal. Adjust the initial Lamb wave according to the instantaneous frequency to obtain the target Lamb wave.

[0086] Furthermore, the objective of this stage is to obtain multiple first-transformed signals through the Hilbert-Huang transform, and then further perform a Hilbert transform to obtain multiple second-transformed signals, thereby adjusting the initial Lamb wave according to the instantaneous frequency of the second-transformed signals. Specifically, step S4 further includes:

[0087] S41: Calculate the local maxima and local minima of the denoised signal, use the local maxima and cubic spline interpolation to obtain the fitted upper envelope, and use the local minima and cubic spline interpolation to obtain the fitted lower envelope.

[0088] S42: Obtain the mean envelope by fitting the upper envelope and the lower envelope, calculate the difference between the denoised signal and the mean envelope, and obtain the first transformed signal;

[0089] S43: Define the transformation completion condition, determine whether the first transformed signal meets the transformation completion condition, and when the first transformed signal does not meet the transformation completion condition, use the obtained first transformed signal as the denoised signal and repeat steps S41 to S42 until the first transformed signal meets the transformation completion condition, thereby obtaining multiple first transformed signals;

[0090] S44: Perform Hilbert transform on each first transformed signal in sequence to obtain multiple second transformed signals, obtain the second signal phase of the second transformed signal, differentiate the second signal phase to obtain the instantaneous frequency of the second transformed signal, adjust the initial Lamb wave according to the instantaneous frequency to obtain the target Lamb wave.

[0091] The specific implementation method for the above steps in this embodiment is as follows:

[0092] First, the local maxima and local minima of the denoised signal need to be obtained. Then, the upper envelope is fitted using the local maxima and cubic spline interpolation, and the lower envelope is fitted using the local minima and cubic spline interpolation. Next, the mean envelope is obtained by fitting the upper and lower envelopes, and the difference between the denoised signal and the mean envelope is calculated, resulting in a first transformed signal. At this point, a transformation completion condition is introduced: the difference between the number of extreme points and the number of zero-crossing points of the first transformed signal is no greater than 1. If the transformation completion condition is met, the transformation ends, and all first transformed signals are obtained. Otherwise, the first transformed signal is used as the denoised signal, and steps S41 to S42 are repeated until the obtained first transformed signal satisfies the transformation completion condition. When the transformation completion condition is met, the original signal can be considered to be the sum of all first transformed signals plus a residual term, and the residual term is sufficiently small.

[0093] Then, by performing Hilbert transform on each of the first transformed signals in sequence, the m-th second transformed signal can be obtained. :

[0094]

[0095] in, Let m be the m-th first transformed signal, and i be the imaginary unit. This indicates that the content within the parentheses is subjected to a Hilbert transform. After obtaining the second transformed signal, its phase can be obtained, which is the phase of the second signal. Differentiating the second signal phase in time yields its instantaneous frequency. The instantaneous frequency of the second transformed signal is compared with the excitation frequency of the excitation mode. If they do not match, the initial Lamb wave needs to be adjusted based on the difference between the instantaneous frequency and the excitation frequency to obtain the target Lamb wave.

[0096] S5: Calculate the attenuation coefficient of the target pipe, construct a fitting formula for the liquid level height and the detection signal using the attenuation coefficient, emit the target Lamb wave and detect it using the Lamb wave sensor to obtain the detection signal, and use the fitting formula and the detection signal to detect the liquid level height in the target pipe.

[0097] Furthermore, the objective of this stage is to calculate the attenuation coefficient of the target pipe and construct a fitting formula, thereby using the fitting formula and the detection signal to detect the liquid level height within the target pipe. Specifically, step S5 further includes:

[0098] S51: Determine the liquid properties of the liquid in the target pipe and the pipe material of the target pipe, and calculate the attenuation coefficient of the target pipe based on the liquid properties and pipe material;

[0099] S52: Determine the fitting coefficient of the target pipeline, and construct the fitting formula for the liquid level height and the detection signal based on the fitting coefficient and the attenuation coefficient;

[0100] S53: The target Lamb wave is emitted and detected by the Lamb wave sensor. A Fourier transform is performed to obtain the detection signal. The liquid level height in the target pipe is calculated using the fitting formula and the detection signal.

[0101] The specific implementation method for the above steps in this embodiment is as follows:

[0102] First, it is necessary to determine the properties of the liquid inside the target pipe and the pipe material. In this embodiment, the liquid inside the target pipe is mainly water condensed from the gas in the pipe, and the pipe material is carbon steel. Based on the liquid properties and pipe material, the attenuation coefficient α of the target pipe can be calculated.

[0103]

[0104] Where f is the frequency of the target Lamb wave, ρ is the density of the pipe material, η is the viscosity coefficient of the pipe material, and c is the speed of sound in the target pipe.

[0105] Then, based on experience, the fitting coefficient b of the target pipeline is determined, and a fitting formula is constructed based on the fitting coefficient b and the attenuation coefficient:

[0106]

[0107] Where y is the normalized amplitude energy of the detection signal, and x is the liquid level height in the target pipe.

[0108] Finally, a Lamb wave sensor is used to detect the target Lamb wave and perform a Fourier transform to convert the signal from the time domain to the frequency domain. The center frequency is then taken to obtain the detected signal. The normalized amplitude energy of the detected signal can then be used to calculate the liquid level height in the target pipe.

[0109] Figure 2 This is a comparison chart of the signal amplitude of the detection signal when the target pipe is empty and when there is liquid accumulation inside. The time unit is microseconds. It can be seen that the signal amplitude increases significantly when there is liquid accumulation, which is obviously different from the case of an empty pipe. Figure 3 This is a comparison graph of the theoretical and measured values ​​of the amplitude energy versus liquid level height curve. It can be seen that the theoretical and measured values ​​obtained by the method provided by this invention are quite close, especially when the liquid level is large. Therefore, it can effectively provide early warning and detection of the liquid level.

[0110] The pipeline liquid level detection device based on Lamb wave provided by the present invention will be described below. The pipeline liquid level detection device based on Lamb wave described below can be referred to in correspondence with the pipeline liquid level detection method based on Lamb wave described above.

[0111] Figure 4 A schematic diagram of a pipeline liquid level detection system based on Lamb waves is shown in the example. Figure 4 As shown, the method for performing the Lamb wave-based pipeline level detection method described above includes:

[0112] Equipment installation module 100: used to select a target pipeline, select an installation position on the target pipeline, and install the Lamb wave sensor at the installation position;

[0113] Initial signal module 200: used to determine the excitation period and excitation frequency, calculate the excitation angle, drive the ultrasonic probe to generate an initial Lamb wave according to the excitation period, excitation frequency and excitation angle, and the Lamb wave sensor measures the initial signal generated by the initial Lamb wave;

[0114] Denoising signal module 300: used to select a window function, weight the initial signal through the window function to obtain a windowed signal, and perform wavelet transform on the windowed signal to obtain a denoised signal;

[0115] Lamb wave adjustment module 400: used to perform Hilbert-Huang transform on the denoised signal to obtain multiple first transform signals, perform Hilbert transform on each first transform signal in sequence to obtain multiple second transform signals, obtain the instantaneous frequency of the second transform signal, and adjust the initial Lamb wave according to the instantaneous frequency to obtain the target Lamb wave;

[0116] Liquid level detection module 500: used to calculate the attenuation coefficient of the target pipe, construct a fitting formula between the liquid level and the detection signal based on the attenuation coefficient, emit a target Lamb wave and detect it through a Lamb wave sensor to obtain a detection signal, and use the fitting formula and the detection signal to detect the liquid level in the target pipe.

[0117] Figure 5 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 5As shown, the electronic device may include: a processor 810, a communication interface 820, a memory 830, and a communication bus 840, wherein the processor 810, the communication interface 820, and the memory 830 communicate with each other via the communication bus 840. The processor 810 can call logical instructions in the memory 830 to execute a Lamb wave-based pipeline liquid level detection method, which includes:

[0118] S1: Select the target pipe, select an installation position on the target pipe, and install the Lamb wave sensor at the installation position;

[0119] S2: Determine the excitation period and excitation frequency, calculate the excitation angle, and drive the ultrasonic probe to generate an initial Lamb wave based on the excitation period, excitation frequency and excitation angle. The Lamb wave sensor measures the initial signal generated by the initial Lamb wave.

[0120] S3: Select a window function, weight the initial signal using the window function to obtain a windowed signal, and perform wavelet transform on the windowed signal to obtain a denoised signal;

[0121] S4: Perform Hilbert-Huang transform on the denoised signal to obtain multiple first transformed signals. Perform Hilbert transform on each first transformed signal in sequence to obtain multiple second transformed signals. Obtain the instantaneous frequency of the second transformed signal. Adjust the initial Lamb wave according to the instantaneous frequency to obtain the target Lamb wave.

[0122] S5: Calculate the attenuation coefficient of the target pipe, construct a fitting formula for the liquid level height and the detection signal using the attenuation coefficient, emit the target Lamb wave and detect it using the Lamb wave sensor to obtain the detection signal, and use the fitting formula and the detection signal to detect the liquid level height in the target pipe.

[0123] Furthermore, the logical instructions in the aforementioned memory 830 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0124] In another aspect, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to perform the aforementioned Lamb wave-based pipeline liquid level detection methods, the method comprising:

[0125] S1: Select the target pipe, select an installation position on the target pipe, and install the Lamb wave sensor at the installation position;

[0126] S2: Determine the excitation period and excitation frequency, calculate the excitation angle, and drive the ultrasonic probe to generate an initial Lamb wave based on the excitation period, excitation frequency and excitation angle. The Lamb wave sensor measures the initial signal generated by the initial Lamb wave.

[0127] S3: Select a window function, weight the initial signal using the window function to obtain a windowed signal, and perform wavelet transform on the windowed signal to obtain a denoised signal;

[0128] S4: Perform Hilbert-Huang transform on the denoised signal to obtain multiple first transformed signals. Perform Hilbert transform on each first transformed signal in sequence to obtain multiple second transformed signals. Obtain the instantaneous frequency of the second transformed signal. Adjust the initial Lamb wave according to the instantaneous frequency to obtain the target Lamb wave.

[0129] S5: Calculate the attenuation coefficient of the target pipe, construct a fitting formula for the liquid level height and the detection signal using the attenuation coefficient, emit the target Lamb wave and detect it using the Lamb wave sensor to obtain the detection signal, and use the fitting formula and the detection signal to detect the liquid level height in the target pipe.

[0130] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0131] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0132] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A pipeline liquid level detection method based on Lamb waves, characterized in that, include: S1: Select the target pipe, select an installation position on the target pipe, and install the Lamb wave sensor at the installation position; S2: Determine the excitation period and excitation frequency, calculate the excitation angle, and drive the ultrasonic probe to generate an initial Lamb wave based on the excitation period, excitation frequency and excitation angle. The Lamb wave sensor measures the initial signal generated by the initial Lamb wave. S3: Select a window function, weight the initial signal using the window function to obtain a windowed signal, and perform wavelet transform on the windowed signal to obtain a denoised signal; S4: Perform Hilbert-Huang transform on the denoised signal to obtain multiple first transformed signals. Perform Hilbert transform on each first transformed signal in sequence to obtain multiple second transformed signals. Obtain the instantaneous frequency of the second transformed signal. Adjust the initial Lamb wave according to the instantaneous frequency to obtain the target Lamb wave. S5: Calculate the attenuation coefficient of the target pipe, construct a fitting formula for the liquid level height and the detection signal using the attenuation coefficient, emit the target Lamb wave and detect it using the Lamb wave sensor to obtain the detection signal, and use the fitting formula and the detection signal to detect the liquid level height in the target pipe.

2. The pipeline liquid level detection method based on Lamb wave according to claim 1, characterized in that, Step S1 further includes: S11: Select the target pipeline, determine the installation interval, and select installation positions at the upper and lower parts of the target pipeline according to the installation interval; S12: Install the Lamb wave sensor at the installation position, and the side of the Lamb wave sensor that is in contact with the target pipe is arc-shaped.

3. The pipeline liquid level detection method based on Lamb waves according to claim 1, characterized in that, Step S2 further includes: S21: Select an excitation mode, and determine the excitation period and the excitation frequency based on the excitation mode; S22: Select an ultrasonic probe, determine the phase velocity of the excitation mode and the sound wave propagation velocity of the ultrasonic probe, and calculate the excitation angle using the sound wave propagation velocity and the phase velocity; S23: Using the excitation angle as the probe angle of the ultrasonic probe, the ultrasonic probe is used to generate an initial Lamb wave according to the excitation period and excitation frequency, and the Lamb wave sensor measures the initial signal generated by the initial Lamb wave.

4. The pipeline liquid level detection method based on Lamb wave according to claim 3, characterized in that, The excitation mode is a longitudinal broadcast mode.

5. The pipeline liquid level detection method based on Lamb wave according to claim 1, characterized in that, Step S3 further includes: S31: Select the Hanning window as the window function, and weight the initial signal using the window function to obtain the windowed signal; S32: The windowed signal is discretized by scale and time axis to obtain a discrete signal. The wavelet basis type and wavelet decomposition level are selected. The discrete signal is decomposed by wavelet according to the wavelet basis type and wavelet decomposition level to obtain wavelet coefficients and wavelet signal. S33: Threshold quantization is performed on the wavelet coefficients to obtain quantization coefficients, and wavelet reconstruction is performed on the wavelet signal using the quantization coefficients to obtain the denoised signal.

6. The pipeline liquid level detection method based on Lamb wave according to claim 1, characterized in that, Step S4 further includes: S41: Calculate the local maxima and local minima of the denoised signal, use the local maxima and cubic spline interpolation to obtain the fitted upper envelope, and use the local minima and cubic spline interpolation to obtain the fitted lower envelope. S42: Obtain the mean envelope by fitting the upper envelope and the lower envelope, calculate the difference between the denoised signal and the mean envelope, and obtain the first transformed signal; S43: Define the transformation completion condition, determine whether the first transformed signal meets the transformation completion condition, and when the first transformed signal does not meet the transformation completion condition, use the obtained first transformed signal as the denoised signal and repeat steps S41 to S42 until the first transformed signal meets the transformation completion condition, thereby obtaining multiple first transformed signals; S44: Perform Hilbert transform on each first transformed signal in sequence to obtain multiple second transformed signals, obtain the second signal phase of the second transformed signal, differentiate the second signal phase to obtain the instantaneous frequency of the second transformed signal, adjust the initial Lamb wave according to the instantaneous frequency to obtain the target Lamb wave.

7. The pipeline liquid level detection method based on Lamb wave according to claim 1, characterized in that, Step S5 further includes: S51: Determine the liquid properties of the liquid in the target pipe and the pipe material of the target pipe, and calculate the attenuation coefficient of the target pipe based on the liquid properties and pipe material; S52: Determine the fitting coefficient of the target pipeline, and construct the fitting formula for the liquid level height and the detection signal based on the fitting coefficient and the attenuation coefficient; S53: The target Lamb wave is emitted and detected by the Lamb wave sensor. A Fourier transform is performed to obtain the detection signal. The liquid level height in the target pipe is calculated using the fitting formula and the detection signal.

8. A Lamb wave-based pipeline level detection system, used to perform the Lamb wave-based pipeline level detection method as described in any one of claims 1 to 7, characterized in that, include: Equipment installation module: used to select the target pipeline, select the installation position on the target pipeline, and install the Lamb wave sensor at the installation position; Initial signal module: used to determine the excitation period and excitation frequency, calculate the excitation angle, drive the ultrasonic probe to generate an initial Lamb wave based on the excitation period, excitation frequency and excitation angle, and the Lamb wave sensor measures the initial signal generated by the initial Lamb wave; Denoising signal module: used to select a window function, weight the initial signal through the window function to obtain a windowed signal, and perform wavelet transform on the windowed signal to obtain a denoised signal; Lamb wave adjustment module: used to perform Hilbert-Huang transform on the denoised signal to obtain multiple first transformed signals, perform Hilbert transform on each first transformed signal in sequence to obtain multiple second transformed signals, obtain the instantaneous frequency of the second transformed signal, and adjust the initial Lamb wave according to the instantaneous frequency to obtain the target Lamb wave; Liquid level detection module: used to calculate the attenuation coefficient of the target pipe, construct a fitting formula between the liquid level and the detection signal based on the attenuation coefficient, emit a target Lamb wave and detect it through a Lamb wave sensor to obtain a detection signal, and use the fitting formula and the detection signal to detect the liquid level in the target pipe.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the pipeline liquid level detection method based on Lamb wave as described in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the pipeline liquid level detection method based on Lamb wave as described in any one of claims 1 to 7.

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