Method for ultrasonic flow measurement of a fluid containing impurities with a double-coupled smart sensor probe

Abstract

This invention relates to the field of flow metering and intelligent sensing technology. In particular, it relates to a method for ultrasonic flow measurement of impurity-containing fluids using a dual-coupled intelligent sensing probe, comprising the steps of: installing a dual-coupled intelligent sensing probe on the outer wall of the pipe under test; acquiring the downstream and upstream propagation times at a first center frequency and a second center frequency; extracting the reflected signal segments corresponding to the reflection from the pipe wall and determining the coupling state parameters, and acquiring impurity characteristic parameters; determining the coupling common-mode correction amount, and determining the impurity common-mode correction amount corresponding to the first and second center frequencies; performing common-mode decoupling correction; selecting a candidate propagation time combination that satisfies the cross-frequency consistency constraint from multiple candidate propagation time combinations; and calculating and outputting the volumetric flow rate. This invention performs common-mode correction on the propagation time and then selects the corrected downstream and upstream propagation time combinations for flow calculation from multiple candidate propagation time combinations.

Description

Technical Field

[0001] This invention relates to the field of flow measurement and intelligent sensing technology, and in particular to a method for measuring the ultrasonic flow rate of impurity-containing fluids using a dual-coupled intelligent sensing probe. Background Technology

[0002] Ultrasonic time-of-flight (TOF) flow measurement typically uses upstream and downstream transducers positioned on either side of the pipe or clamped to the pipe wall to acquire the downstream and upstream propagation times, respectively, and calculates the flow velocity and flow rate of the fluid within the pipe based on the difference between the two. To improve the stability of the propagation time extraction, existing technologies utilize "windowing" of the received signal. For example, CN106855424B discloses an ultrasonic flow measurement method that applies windowing processing to the received signal, calculates the signal delay (ΔTOF) using only the windowed portion, and calculates the fluid flow rate accordingly.

[0003] However, in applications involving fluids containing impurities (such as fluids carrying particles, bubbles, or other impurities), and when the coupling conditions of the clamp-on probe fluctuate, the amplitude, attenuation pattern, and arrival waveform of the received signal may change. Furthermore, multipath echoes and multiple local peaks may appear in the received signal. In such cases, even if the received signal is windowed, multiple candidate peaks may still exist within the window, leading to uncertainty in peak selection when extracting the propagation time between upstream and downstream flows. This results in deviations in the calculation results based on the propagation time difference.

[0004] Furthermore, existing technologies also include schemes that use calibration coefficient lookup tables for multi-level dynamic compensation. For example, the scheme disclosed in CN105091970A establishes a calibration coefficient lookup table to compensate for deviations caused by factors such as measurement time, density, and temperature, and calculates the flow rate accordingly. These schemes typically still use the extracted propagation time or time difference as input. When the propagation time extraction itself is affected by factors such as impurity scattering and coupling fluctuations, leading to an increase in candidate peaks or unstable peak selection, the compensation process may still be affected by the uncertainty of the propagation time input.

[0005] Meanwhile, dual-frequency time-of-flight detection methods, such as the scheme disclosed in CN102866261B, provide a framework for calculating time of flight under multi-frequency conditions to address measurement issues such as phase drift. However, in scenarios involving fluids containing impurities and where the received signal has multiple candidate peaks, selecting an effective combination of downstream and upstream propagation times for flow calculation from among multiple candidate propagation times still requires further refinement of criteria and processing procedures.

[0006] Therefore, the main technical problem to be solved in the existing technology is: in ultrasonic flow measurement of fluids containing impurities, when the coupling state between the probe and the pipeline fluctuates and there are multiple candidate peaks in the received signal, how to reliably determine the downstream propagation time and the upstream propagation time (or an effective combination thereof) that can be used for flow calculation, so as to reduce the measurement deviation caused by peak selection uncertainty. Summary of the Invention

[0007] To overcome the aforementioned technical deficiencies, the present invention aims to provide a method for measuring the ultrasonic flow rate of impurity-containing fluids using a dual-coupled intelligent sensing probe. This invention measures the propagation time using dual-frequency bidirectional propagation time and performs common-mode correction on the propagation time based on coupling state parameters, impurity characteristic parameters, and dual-frequency common-mode difference components. Then, based on cross-frequency consistency constraints, a corrected upstream and downstream propagation time combination is selected from multiple candidate propagation time combinations for flow rate calculation.

[0008] This invention discloses a method for measuring the ultrasonic flow rate of fluids containing impurities using a dual-coupled smart sensing probe, comprising the following steps: S1. A dual-coupled intelligent sensing probe is installed on the outer wall of the pipe to be tested, which carries fluid containing impurities. The dual-coupled intelligent sensing probe includes at least an upstream ultrasonic transducer, a downstream ultrasonic transducer, an impurity sensing component, and a probe processing unit. The impurity sensing component includes an intelligent sensing element. The probe processing unit and the impurity sensing component constitute an intelligent sensing system. S2, at the first center frequency With the second center frequency Bidirectional propagation time measurements were performed separately to obtain the downstream propagation time at the first center frequency. With the time of reverse propagation and downstream propagation time at the second center frequency With the time of reverse propagation ; S3. The probe processing unit extracts the reflected signal segment corresponding to the reflection from the wall of the pipe being measured from the received signal and determines the coupling state parameters. The impurity characteristic parameters are obtained by the impurity sensing component. ; S4, The probe processing unit is based on the coupling state parameters. Determine the coupling common-mode correction amount And based on impurity characteristic parameters With dual-frequency common-mode differential components Determine the impurity common-mode correction amount corresponding to the first center frequency. And the common-mode correction amount of impurities corresponding to the second center frequency ,in: S5. The downstream propagation time is processed by the probe processing unit. , time of reverse transmission Downstream propagation time , time of reverse transmission Performing common-mode decoupling correction yields: S6. When a candidate propagation time set exists, the probe processing unit combines the elements of the candidate propagation time set to form multiple candidate propagation time combinations, and selects the candidate propagation time combination that satisfies the cross-frequency consistency constraint from the multiple candidate propagation time combinations, wherein the cross-frequency consistency constraint includes at least: in, The preset threshold; S7, selected by the probe processing unit based on cross-frequency consistency constraints. and Calculate volumetric flow rate and output volumetric flow rate .

[0009] Preferably, volumetric flow rate Satisfy the following calculation formula: in, The inner diameter of the pipe. The sound path length, For installation angle, For the cross-sectional area of ​​circulation, The average flow velocity, Pi is a constant. and These refer to the corrected reverse propagation time and the corrected forward propagation time selected by the cross-frequency consistency constraint in step S7 of claim 1, respectively.

[0010] Preferably, in step S6, when multiple candidate propagation time combinations exist, the candidate propagation time combination is selected by minimizing the consistency loss function, and the consistency loss function... satisfy: ; in, , , To preset weights, and These are the normalized correlation coefficients of the cross-correlation peak values ​​corresponding to the first center frequency and the second center frequency, respectively.

[0011] Preferably, the candidate propagation time set is obtained as follows: an effective window is set for the received signal, and within the effective window, a cross-correlation operation is performed on the reference templates corresponding to the received signal and the excitation signal, extracting the first... The time delay corresponding to each local peak is used as a candidate propagation time. Candidate propagation time subsets are established for downstream and upstream, and for the first and second center frequencies, respectively. These candidate propagation time subsets constitute the candidate propagation time set. It is a preset positive integer.

[0012] Preferably, the coupling state parameters in step S3 The determination includes: extracting the first reflected signal segment and the second reflected signal segment from the received signal, and calculating the energy of the first reflected signal segment respectively. Energy of the second reflected signal segment The coupling state parameters are determined according to the following formula. : And energy satisfy: in, For the corresponding reflected signal segment Amplitude at each sampling point, This represents the number of sampling points for the corresponding reflected signal segment.

[0013] Preferably, the coupling common-mode correction amount From the coupling state parameters Piecewise monotonic mapping It is determined that the piecewise monotonic mapping satisfies the upper and lower bound constraints imposed on the mapping values ​​of each segment endpoint.

[0014] Preferably, impurity characteristic parameters The quantity obtained by calibration of the turbidity signal output by the intelligent sensing element Together with the ultrasonic attenuation difference component, the ultrasonic attenuation difference component is determined by the cross-correlation peak amplitude and satisfies: in, , , These are preset parameters. It is the natural logarithm function; The average of the peak amplitudes of the downstream cross-correlation and the peak amplitudes of the upstream cross-correlation corresponding to the candidate propagation time combinations selected in step S6 of claim 1 at the first center frequency. It is the average of the peak amplitudes of the downstream cross-correlation and the peak amplitudes of the upstream cross-correlation corresponding to the selected candidate propagation time combination at the second center frequency.

[0015] Preferably, the impurity common-mode correction amount Common mode correction with impurities Two-dimensional constraint lookup table mapping Output, and satisfy the inter-frequency difference constraint: in, For preset coefficients, This is a preset threshold.

[0016] Preferably, the half width of the effective window From the coupling state parameters With impurity characteristic parameters They are jointly determined and satisfy the following conditions: in, , , These are the preset window parameters.

[0017] Preferably, the probe processing unit determines the quality indicators. And based on quality indicators Control whether to output volumetric flow rate And quality indicators satisfy: in, This represents the consistency loss function value.

[0018] Preferably, the dual-coupled smart sensing probe includes two measurement acoustic paths with different sound paths, denoted as follows: The probe processing unit performs steps S2 to S6 of claim 1 on the two measurement acoustic paths respectively, to obtain the corresponding values ​​of the two measurement acoustic paths. and The equivalent flow-direction sensitive component used to calculate the volumetric flow rate is determined by weighted least squares.

[0019] Preferably, the first center frequency With the second center frequency The excitation signal uses a distinguishable orthogonal coding sequence, and the probe processing unit performs matched filtering on the received signal to separate the corresponding correlation peaks and form a candidate propagation time set.

[0020] Preferably, it further includes an online update step: when a reference volumetric flow rate calibration value exists. At that time, based on the reference volumetric flow rate calibration value With output volumetric flow rate Difference update two-dimensional constraint lookup table mapping The table entries are updated, and constraint projection processing is performed on the table entry set after the update so that the updated table entry set satisfies the frequency difference constraint.

[0021] Preferably, it also includes version management and rollback steps: mapping the updated two-dimensional constraints to a lookup table. Generate a version identifier and write it to non-volatile memory; when the inequality of the cross-frequency consistency constraint in step S6 of claim 1 is not satisfied for multiple consecutive measurement cycles and the duration exceeds a preset time, the two-dimensional constraint lookup table is mapped. Roll back to the set of entries corresponding to the previous version identifier.

[0022] Preferably, the method further includes a sensor degradation step: when the turbidity signal is unavailable or exceeds a preset range, the probe processing unit uses the ultrasonic attenuation difference component to replace the turbidity signal in the impurity characteristic parameters. The determination is made while keeping the calculation process of steps S4 to S7 of claim 1 unchanged.

[0023] Compared with existing technologies, the above technical solution has the following advantages: 1. This invention achieves stable determination of the propagation time of fluids containing impurities under multi-path and multi-peak interference by combining dual-frequency bidirectional propagation time measurement with cross-frequency consistency screening of candidate propagation time combinations, thereby significantly improving the stability and accuracy of ultrasonic flow measurement.

[0024] 2. This invention introduces coupling state parameters and determines the coupling common-mode correction amount accordingly. At the same time, it combines impurity characteristic parameters and dual-frequency common-mode differential components to output two-frequency impurity common-mode correction amounts, thereby realizing common-mode decoupling correction of coupling disturbances and impurity disturbances, and reducing the systematic deviation of the measurement results caused by probe coupling fluctuations and impurity changes.

[0025] 3. This invention uses two-dimensional constraint lookup table mapping and applies inter-frequency difference constraints to ensure that the common mode correction of impurities between the two frequencies maintains a consistent relationship under the constraint conditions, thereby improving the physical consistency and parameter controllability of cross-frequency fusion and reducing the risk of misselection of peaks and mismeasurement caused by cross-frequency drift.

[0026] 4. This invention selects the best among multiple candidate propagation time combinations based on the consistency loss function, and comprehensively considers the consistency of cross-frequency flow-sensitive components, the consistency of cross-frequency common modulus, and the confidence of related peaks, which helps to further reduce the probability of misselected peaks in complex noise and strong scattering environments.

[0027] 5. This invention uses quality indicators to gating control of the output and triggers recalculation or protection strategies when the quality indicators are low or the consistency constraints are not met, thereby reducing the probability of low-reliability measurement results being output and improving the reliability of engineering applications.

[0028] 6. The present invention adopts a strategy of adaptively adjusting the effective window half-width according to the coupling state parameters and impurity characteristic parameters, so that the candidate peak search range matches the changes in operating conditions, takes into account both candidate peak coverage and spurious peak suppression ability, and improves adaptability under different turbidity and different coupling conditions.

[0029] 7. This invention provides two different sound path measurement sound paths and fuses the equivalent flow direction sensitive component in a weighted least squares manner. It can utilize multi-path redundancy to improve anti-interference capability and reduce the impact of single-path anomalies on the final flow output.

[0030] 8. The present invention performs online updates when a reference volumetric flow rate calibration value exists, and performs constraint projection processing on the table entry set after the update to maintain the inter-frequency difference constraint, enabling the system to adapt to operating condition drift during long-term operation, while avoiding the update from destroying the inter-frequency consistency mechanism.

[0031] 9. This invention uses version management and rollback mechanisms to roll back to the previous version's entry set when cross-frequency consistency constraints are not consistently met, thereby suppressing performance degradation caused by the accumulation of abnormal updates and improving the stability and recoverability of long-term operation.

[0032] 10. The present invention sets up a sensor degradation strategy, which replaces the turbidity signal with the ultrasonic attenuation difference component to participate in the determination of impurity characteristic parameters when the turbidity signal is unavailable or exceeds the preset range, while keeping the subsequent calculation process unchanged, thereby enhancing the continuous measurement capability under abnormal sensing conditions. Attached Figure Description

[0033] Figure 1 This is a flowchart illustrating the ultrasonic flow measurement method for impurity-containing fluids using a dual-coupled intelligent sensing probe according to the present invention. Figure 2 A schematic diagram illustrating the process of measuring and determining the propagation time of a dual-frequency, bidirectional transmission. Figure 3 A schematic diagram illustrating the construction of candidate propagation time subsets and the extraction of candidate peaks; Figure 4 This is a schematic diagram of the two-dimensional constraint lookup table mapping and constraint projection processing flow. Figure 5 This is a schematic diagram of the measurement error curves between the control method and the method of the present invention; Figure 6 This is a schematic diagram comparing the invalid / abnormal ratios of the control method and the method of the present invention. Detailed Implementation

[0034] The advantages of the present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments.

[0035] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0036] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0037] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0038] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "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 this 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 this invention.

[0039] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0040] In the following description, suffixes such as "module," "part," or "unit" used to denote elements are used only for the convenience of the description of the invention and have no specific meaning in themselves. Therefore, "module" and "part" can be used interchangeably.

[0041] This embodiment provides a method for ultrasonic flow measurement of impurity-containing fluids using a dual-coupled intelligent sensing probe, used to measure and output the volumetric flow rate within a test pipe carrying the impurity-containing fluid. The impurity-containing fluid can be a liquid medium containing suspended particulate matter, microbubbles, or other impurity components. The overall process flow is as follows: Figure 1 As shown.

[0042] In this embodiment, a dual-coupled intelligent sensing probe is installed on the outer wall of the pipe carrying the fluid containing impurities. The dual-coupled intelligent sensing probe includes at least an upstream ultrasonic transducer, a downstream ultrasonic transducer, an impurity sensing component, and a probe processing unit. The impurity sensing component includes an intelligent sensing element; the probe processing unit and the impurity sensing component constitute an intelligent sensing system. Further, the upstream and downstream ultrasonic transducers are used to form an ultrasonic propagation channel in the fluid containing impurities within the pipe, so as to generate received signals in the downstream and upstream directions respectively; the impurity sensing component is used to acquire turbidity signals to characterize the impurity state of the fluid; the probe processing unit is used to perform data processing processes such as sampling, cross-correlation calculation, candidate peak extraction, coupling state parameter determination, impurity characteristic parameter determination, common-mode correction, cross-frequency consistency screening, volumetric flow rate calculation, online update, version management and rollback, and sensor degradation. The dual-frequency bidirectional propagation time acquisition process is as follows: Figure 2 As shown, the candidate peak extraction is illustrated in the diagram. Figure 3 As shown, the two-dimensional constraint lookup table mapping and constraint projection processing are illustrated in the figure. Figure 4 As shown, the error curve and anomaly ratio diagram of the control experiment are respectively as follows: Figure 5 and Figure 6 As shown.

[0043] For ease of explanation, this embodiment provides a set of optional parameter configurations as an example. These parameters are used to explain the calculation chain and example data caliber, and do not constitute a limitation. In practice, they can be adjusted according to pipe diameter, medium attenuation, on-site noise level, and sampling capability.

[0044] In this embodiment, with the first center frequency With the second center frequency Bidirectional propagation time measurements were performed separately to obtain the downstream propagation time at the first center frequency. With the time of reverse propagation and downstream propagation time at the second center frequency With the time of reverse propagation Furthermore, the received signal in the downstream direction is formed by the upstream ultrasonic transducer and the downstream ultrasonic transducer, while the received signal in the upstream direction is formed by the downstream ultrasonic transducer and the upstream ultrasonic transducer; the above description is used to explain the direction finding organization method of bidirectional propagation time measurement.

[0045] In this embodiment, each measurement forms a received sampling sequence. The sampling frequency adopts The sampling period adopts and satisfy .

[0046] When the sampling frequency is 40MHz, the sampling period is 25ns. Furthermore, an effective window is set for the received signal, and within the effective window, a cross-correlation operation is performed between the received signal and the reference template corresponding to the excitation signal to form a cross-correlation sequence. The reference template uses... Cross-correlation sequences were used This indicates that a time-delayed index is used. This indicates that the cross-correlation sequences satisfy... .

[0047] Among them, the effective length of cross-correlation The number of valid samples participating in the cross-correlation summation is determined by the reference template length and the truncation window length; summation index. This is the sampling point index. The center of the effective window can be determined by the predicted arrival time. The half-width of the effective window is B, thus the effective window interval is... This can be converted to a time delay index interval to limit the candidate peak search range. The effective window center can be determined by the predicted arrival time, denoted as . .

[0048] In this embodiment, the time delays corresponding to the top M local peaks of the cross-correlation sequence within the effective window are extracted as candidate propagation times. Candidate propagation time subsets are established for downstream and upstream, and for the first and second center frequencies, respectively, and these subsets constitute the candidate propagation time set. Further, the local peak determination preferably adopts a joint rule of "neighborhood maximum + noise threshold," meaning that when the value of the cross-correlation sequence at a certain time delay index is greater than the values ​​in the left and right neighboring ranges and higher than the noise threshold, that time delay index is determined to be a local peak. The noise threshold can be generated from the mean and standard deviation of the cross-correlation sequence within the effective window; for example, the mean is taken plus several times the standard deviation to suppress spurious peaks caused by noise. Further, to improve propagation time resolution, subsampling interpolation refinement is preferably performed near the local peaks. For example, three-point parabolic interpolation is used to take three cross-correlation values ​​near the peak index and correct the peak index, thereby reducing the propagation time quantization error from the sampling period order of magnitude to a smaller order of magnitude. Interpolation refinement does not change the number of candidate peaks or the candidate set structure; it is only used to improve the accuracy of propagation time estimation.

[0049] Example 1 (Generation of Candidate Propagation Time Subset): In one measurement cycle, the sampling frequency is set to 40MHz and the sampling period to 25ns. The time delay index corresponding to the first 5 local peaks detected by the downstream measurement at the first center frequency within the effective window is... The candidate propagation time is The candidate propagation time for the first center frequency countercurrent measurement is: The candidate propagation time for the second center frequency downstream measurement is: The candidate propagation time for the second center frequency countercurrent measurement is... The above four candidate propagation time subsets are summarized in Table 1.

[0050] Example Table 1 of Candidate Propagation Time Subsets In this embodiment, when a set of candidate propagation times exists, multiple candidate propagation time combinations are formed by combining the elements of the candidate propagation time set. Each candidate propagation time combination includes a first center frequency downstream propagation time candidate value, a first center frequency upstream propagation time candidate value, a second center frequency downstream propagation time candidate value, and a second center frequency upstream propagation time candidate value. Subsequently, common mode correction and cross-frequency consistency screening will be performed to determine the effective combination for traffic calculation.

[0051] Furthermore, in order to reduce cross-frequency interference and improve the separability of correlation peaks, the excitation signals of the first center frequency and the second center frequency preferably adopt distinguishable orthogonal coding sequences. The probe processing unit performs matched filtering on the received signal to separate the corresponding correlation peaks and form a candidate propagation time set. In a computational sense, the output of matched filtering is equivalent to the output of cross-correlation. Therefore, in this embodiment, cross-correlation operation is still used for unified description.

[0052] In this embodiment, the probe processing unit extracts the reflected signal segment corresponding to the reflection from the wall of the pipe under test in the received signal and determines the coupling state parameters. Furthermore, determining the coupling state parameters includes: extracting the first reflected signal segment and the second reflected signal segment from the received signal, and calculating the energy of the first reflected signal segment respectively. Energy of the second reflected signal segment , and according to Determine the coupling state parameters. Energy E satisfies... .

[0053] in, For the corresponding reflected signal segment Amplitude at each sampling point, This represents the number of sampling points for the corresponding reflected signal segment. Furthermore, the interception positions of the first and second reflected signal segments can be determined based on the known arrival order of the reflected echoes in the received signal, and can be intercepted using a fixed time window or an adaptive threshold method to ensure the stability of energy calculation.

[0054] In this embodiment, the impurity sensing component acquires the turbidity signal and outputs it by the intelligent sensing element; the turbidity signal is calibrated to obtain the turbidity calibration quantity. Furthermore, impurity characteristic parameters The impurity characteristic parameters are determined by the probe processing unit based on the turbidity calibration quantity and the ultrasonic attenuation difference component, where the ultrasonic attenuation difference component is determined by the cross-correlation peak amplitude, and the impurity characteristic parameters satisfy... .in, , , These are preset parameters. It is the natural logarithm function; The average of the peak amplitudes of the downstream cross-correlation and the peak amplitudes of the upstream cross-correlation corresponding to the candidate propagation time combinations selected under the first center frequency and the cross-frequency consistency constraint is used. This is the average of the peak amplitudes of the downstream cross-correlation and the peak amplitudes of the upstream cross-correlation corresponding to the selected candidate propagation time combination at the second center frequency. By using this approach, the impurity characteristic parameters are made consistent with the candidate combination selection process, thereby avoiding instability caused by changes in the amplitude value range.

[0055] In this embodiment, the probe processing unit is based on coupling state parameters. Determine the coupling common-mode correction amount Furthermore, the coupling common-mode correction is derived from a piecewise monotonic mapping with respect to the coupling state parameters. It is determined that the piecewise monotonic mapping satisfies upper and lower bound constraints on the mapping values ​​at each segment endpoint. Preferably, a lookup table can be used to implement the piecewise monotonic mapping, and upper and lower bounds can be set at the endpoints of the table entries to avoid abnormal coupling leading to divergence of the correction quantity. As an implementable example, it can be taken that: when hour ,when hour ,when hour ,when hour Furthermore, constraints are set for each endpoint, which do not exceed the preset upper limit and are not lower than the preset lower limit.

[0056] In this embodiment, the probe processing unit is based on impurity characteristic parameters. With dual-frequency common-mode differential components Determine the impurity common-mode correction amount corresponding to the first center frequency. And the common-mode correction amount of impurities corresponding to the second center frequency The dual-frequency common-mode differential component satisfies .

[0057] Furthermore, and Two-dimensional constraint lookup table mapping Output, and satisfy the inter-frequency difference constraint: in For preset coefficients, The preset threshold is used. Furthermore, the two-dimensional constraint lookup table mapping can be implemented using two-dimensional grid entries and bilinear interpolation, that is, interpolation is performed on the dimensions of impurity characteristic parameters and dual-frequency common-mode difference components to obtain continuous output; when the input falls outside the boundary, the output can be obtained by boundary truncation or extrapolation, and preferably still satisfies the inter-frequency difference constraint.

[0058] Furthermore, when a set of candidate propagation times exists, multiple candidate propagation time combinations are formed by combining the elements of the candidate propagation time set, and a candidate propagation time combination that satisfies the cross-frequency consistency constraint is selected from the multiple candidate propagation time combinations, wherein the cross-frequency consistency constraint includes at least: in A preset threshold is used. Furthermore, when multiple candidate propagation time combinations exist, the candidate propagation time combination is selected by minimizing the consistency loss function. satisfy .

[0059] in , , To preset weights, and These are the normalized correlation coefficients of the cross-correlation peak values ​​corresponding to the first and second center frequencies, respectively. Through the above screening, the corrected propagation time combination used for traffic calculation can be stably determined in scenarios with multiple candidate peaks.

[0060] In this embodiment, the probe processing unit is selected based on cross-frequency consistency constraints. and Calculate volumetric flow rate And output, the volumetric flow rate satisfies: in, The inner diameter of the pipe. The sound path length, For installation angle, For the cross-sectional area of ​​circulation, The average flow velocity, Pi is a constant. and These are the corrected backflow propagation time and the corrected forward propagation time selected for the cross-frequency consistency constraint, respectively.

[0061] In this embodiment, the probe processing unit determines the quality indicators. And control whether to output volumetric flow rate based on quality indicators, the quality indicators must meet: in This represents the consistency loss function value. Furthermore, when the quality index falls below the threshold, the volumetric flow rate may not be output and a recalculation may be triggered; when the quality index is low for multiple consecutive cycles and the cross-frequency consistency constraint is not met, a rollback logic may be triggered to improve long-term stability.

[0062] Furthermore, the half width of the effective window It is determined by both the coupling state parameters and the impurity characteristic parameters, and satisfies the following conditions: in , , These are preset window parameters. Through this adaptive setting, when coupling deteriorates or impurities increase, leading to peak broadening and sidelobe enhancement, the effective window half-width is increased to increase candidate peak coverage; when coupling is good and impurities are few, the effective window half-width is decreased to reduce the introduction of spurious peaks.

[0063] In this embodiment, the dual-coupled smart sensing probe includes two measurement acoustic paths with different sound paths, denoted as follows: The probe processing unit performs dual-frequency bidirectional timing measurement, candidate combination construction, common-mode correction, and cross-frequency consistency screening processes on the two measurement acoustic paths respectively, to obtain the corresponding... and Furthermore, to calculate the equivalent flow-direction sensitive component required for volumetric flow rate, the first... The direction-sensitive component of the sound path is The equivalent flow-sensitive component is determined using weighted least squares. It can be expressed as minimizing the objective function: in Let be the acoustic path weights. From this objective function, a closed-form solution can be obtained: Furthermore, the path weights can be correlated with the confidence level of the correlation peaks. For example, the path weights can be correlated with the normalized correlation coefficient, coupling state parameters, and consistency loss function corresponding to that path, thereby reducing the weights of paths with high noise, poor coupling, or poor consistency. Then... Substituting the average flow velocity and volumetric flow rate into the calculation formula, the volumetric flow rate output after fusion of the acoustic path is obtained.

[0064] In this embodiment, an online update step is also included: when a reference volumetric flow rate calibration value exists. At that time, based on With output volumetric flow rate Difference update two-dimensional constraint lookup table mapping The table entries are updated, and constraint projection processing is performed on the table entry set after the update so that the updated table entry set satisfies the frequency difference constraint.

[0065] Furthermore, online updates can be performed as follows: Define traffic error: Update step size coefficient Generate an incremental update for the table entry, such as for the current input. Execution of the positioned grid table entry: Alternatively, update increments can be assigned to the four corner entries using bilinear interpolation weights to avoid local abrupt changes. After the update, the inter-frequency difference constrained residuals can be calculated. when When remains unchanged; when Constraint projection processing is performed at that time. As a feasible constraint projection method, symmetric projection can be used, let: And execute: This allows the absolute value of the updated residual to return to the threshold range and minimizes the amount of change to the table entries.

[0066] It should be noted that, For symbolic functions, Take 1 at time. Take -1 at time, =0 is taken as 0.

[0067] In this embodiment, version management and rollback steps are also included: generating a version identifier for the updated two-dimensional constraint lookup table mapping and writing it to non-volatile memory; when the inequality that does not satisfy the cross-frequency consistency constraint is not met in multiple consecutive measurement cycles and the duration exceeds a preset time, the two-dimensional constraint lookup table mapping is rolled back to the table set corresponding to the previous version identifier. Further, the triggering criterion can be implemented by simultaneously maintaining a "continuous non-compliance counter" and a "cumulative duration timer": when the cross-frequency consistency constraint is not met, the continuous non-compliance counter is incremented by 1 and the duration is accumulated; when the cross-frequency consistency constraint is met, the counter is reset to zero and the accumulated duration is reset to zero; when the continuous non-compliance counter reaches the continuous cycle threshold... And the cumulative duration exceeds the duration threshold. A rollback is triggered in a timely manner. This mechanism avoids frequent rollbacks caused by short-term disturbances and provides recovery capabilities against long-term anomalies.

[0068] In this embodiment, a sensor degradation step is also included: when the turbidity signal is unavailable or exceeds a preset range, the probe processing unit uses the ultrasonic attenuation difference component to replace the turbidity signal in the impurity characteristic parameters. The determination of the calibration parameters, common-mode calibration, cross-frequency consistency screening, and volumetric flow rate calculation process should remain unchanged. As one implementation method, the turbidity calibration value can be set to a default value and only used... The term determines the characteristic parameters of the impurities, satisfying... .in , The caliber is still determined by the average value of the peak amplitude of the cross-correlation between the selected candidate propagation time combination and the downstream and upstream, so as to ensure consistency of caliber and continuity of calculation process.

[0069] In this embodiment, to visually compare the measurement differences under conditions containing impurities and coupled fluctuations, an experimental comparison is established between the control method and the method of this embodiment. The control method uses a windowed ΔTOF processing method instead of cross-frequency consistency screening and coupling, and impurity common-mode correction closed loop; the method of this embodiment adopts the complete process described above. The experiment uses a metrology-grade mass flow meter to convert the reference volumetric flow rate calibration value, and simulates complex operating conditions by changing the turbidity and coupled fluctuation levels. The error curves and anomaly scale diagrams are shown below. Figure 5 and Figure 6 As shown in Table 2, the experimental data are summarized using the "highly coupled fluctuation condition" as a representative example.

[0070] Summary Table 2 of Control Experiment Data Furthermore, the same trend can be observed under medium-coupling and low-coupling fluctuation conditions. That is, as turbidity increases, the error and anomaly ratio of the control method increase significantly. However, this embodiment, through cross-frequency consistency screening of candidate propagation time combinations combined with coupling and impurity common-mode correction, enables a more stable determination of the propagation time combination used for flow calculation in multi-candidate peak scenarios, thereby maintaining a lower error and a lower anomaly ratio. This trend can be explained by… Figure 5 and Figure 6 The curves / bar charts shown intuitively reflect this.

[0071] It should be noted that in this embodiment, by measuring the bidirectional propagation time of dual frequencies and constructing a set of candidate propagation times and combinations of candidate propagation times, common-mode correction is performed in combination with coupling state parameters and impurity characteristic parameters. Then, effective propagation time combinations are selected based on cross-frequency consistency constraints, which reduces the uncertainty of peak selection in scenarios with multiple paths and multiple candidate peaks caused by impurity fluids. At the same time, by using two-dimensional constraint lookup table mapping and inter-frequency difference constraints, and performing constraint projection processing after online updates, the consistency relationship between the two-frequency impurity common-mode correction quantities is maintained. Furthermore, by reducing low-confidence outputs through quality index gating, improving recovery capabilities under abnormal conditions through version management and rollback, and maintaining measurement continuity when turbidity signals are abnormal through sensor degradation, lower errors and a lower anomaly ratio are demonstrated under conditions of high turbidity and high coupling fluctuations.

[0072] It should be noted that in this embodiment, the methods for obtaining the downstream propagation time and the upstream propagation time are consistent. Both are obtained through a process of "received sampling sequence—cross-correlation sequence—effective window—local peak—candidate propagation time," and the effective propagation time combination is determined through cross-frequency consistency screening. Further, during downstream measurement at the first center frequency, the probe processing unit records the received sampling sequence formed by the upstream ultrasonic transducer component transmitting and receiving it in the downstream ultrasonic transducer component. A cross-correlation sequence is formed using a reference template corresponding to the excitation signal, and the preceding propagation time is extracted within the effective window. The candidate propagation times corresponding to each local peak are used as the first center frequency downstream candidate propagation time subset. During the first center frequency upstream measurement, the probe processing unit records the received sampling sequence formed by the downstream ultrasonic transducer receiving the signal, and uses the same aperture to form the first center frequency upstream candidate propagation time subset. The processing method for the second center frequency downstream and upstream is the same as for the first center frequency, only the reference template is mapped to the center frequency. The four candidate propagation time subsets formed through the above four measurements constitute the candidate propagation time set, and their elements are combined to form multiple candidate propagation time combinations. After common-mode correction, cross-frequency consistency screening is performed to obtain the final propagation time for flow calculation. and .

[0073] It should also be noted that in this embodiment, the truncation of the first and second reflected signal segments preferably satisfies the principles of "stable time position, fixed or adaptive window length, and avoidance of cross-segment overlap" to ensure energy ratio It is sensitive to coupling variations and robust to random noise. Furthermore, the window length of the reflected signal segment can be a fixed duration covering the main lobe width of the main reflected echo and its neighborhood, and this duration remains consistent throughout each measurement cycle. When there is a slow drift at the arrival time of the echo, adaptive gating can be achieved by finding the peak position of the reflected echo within a small search window and truncating a fixed window length centered on the peak, thereby improving... and Stability is calculated. Furthermore, energy calculations are performed using a sum-of-squares form. The number of sampling points With sampling period The window length is determined jointly, and it is preferable to keep the window length consistent across different measurement periods to avoid changes in the energy dimension with the window length.

[0074] In this embodiment, the peak amplitude of cross-correlation and The definition adopts the caliber of "average peak amplitude of the forward / backward cross-correlation corresponding to the finally selected candidate propagation time combination" to ensure that the impurity characteristic parameters are consistent with the propagation time selection. Furthermore, the peak amplitude of the cross-correlation can be the absolute value of the cross-correlation sequence at the selected peak index, or it can be the local maximum value at several points near the selected peak to reduce amplitude fluctuations caused by peak index jitter; as long as the same caliber is used between the first and second center frequencies, and between forward and backward propagation. Furthermore, the normalized correlation coefficient... , The relative matching index, which falls between 0 and 1, can be obtained by normalizing the cross-correlation peak value and the sequence energy. For example, the cross-correlation sequence peak value can be divided by the square root of the received sample sequence energy and the reference template energy to obtain the relative matching index. In this embodiment, and As a quality indicator With consistency loss function The input only needs to maintain the same aperture between the two frequencies.

[0075] In this embodiment, the two-dimensional constraint lookup table mapping can be implemented using two-dimensional grid table entries, and continuous output is obtained using bilinear interpolation. Furthermore, when the impurity characteristic parameters... Falling between two adjacent grid rows and dual-frequency common-mode difference components When it falls between two adjacent grid columns, you can first... Perform linear interpolation in the direction to obtain two column-direction interpolation results, then... The direction is used to perform linear interpolation to obtain the final output, thereby achieving the desired result. and Continuous estimation; when or When the value falls outside the grid boundary, a boundary truncation method can be used to restrict it to the minimum / maximum grid boundary, and then interpolation can be performed while still verifying the inter-frequency difference constraint. Furthermore, if local changes in entries after online updates cause the inter-frequency difference constraint residual to exceed the limit, adjustments should be made using the aforementioned symmetrical projection method. and To meet This maintains the stability of cross-frequency consistency screening.

[0076] In this embodiment, online updates are performed using... To drive the generation of update increments, further, when the two-dimensional constraint lookup table mapping uses grid entries and bilinear interpolation, the update increments can be distributed to the four corner entries according to the bilinear interpolation weights, so that the update propagates smoothly near the input point and avoids single-point mutations; for example, the input point is located at... direction and The relative positions of the directions are used as weights to apply proportional updates to the entries at the four corner points, thereby maintaining the continuity of the entry surface. Furthermore, frequency difference constraint verification and constraint projection processing are performed immediately after the update to prevent constraint violation caused by cumulative updates.

[0077] It should be noted that in this embodiment, the rollback trigger also considers the "continuous period threshold". "and duration threshold" To avoid false triggering due to short-term disturbances, cycles where cross-frequency consistency constraints are not met can be counted as abnormal cycles, and their duration can be accumulated within these abnormal cycles. When a cycle that meets the cross-frequency consistency constraints occurs, the count and accumulated time are reset to zero, thus ensuring that the trigger is a "continuous anomaly." Furthermore, quality index gating can be used as one of the prerequisites for rollback. That is, when the quality index is consistently below the threshold and cross-frequency consistency constraints are continuously not met, rollback is triggered first. When cross-frequency consistency is only occasionally not met but the quality index is high, recalculation or window expansion is triggered first instead of rollback, thereby reducing the rollback frequency and improving long-term stable operation capability.

[0078] In this embodiment, impurity characteristic parameters Used to characterize the impurity state of fluids containing impurities, and quantified by turbidity standardization. The impurity characteristic parameters are determined together with the ultrasonic attenuation difference component. Furthermore, considering that the impurity sensing component includes intelligent sensing elements, and that the impurity sensing component and the probe processing unit constitute an intelligent sensing system, therefore, "acquiring impurity characteristic parameters..." In terms of functional definition, this can be understood as: the impurity sensing component outputs a turbidity signal through an intelligent sensing element and completes calibration mapping to obtain... Simultaneously, it provides turbidity calibration data to the probe processing unit; the probe processing unit acquires the cross-correlation peak amplitude corresponding to the candidate propagation time combination and forms... Finally, the turbidity calibration quantity and the ultrasonic attenuation difference component are fused to obtain the impurity characteristic parameters. In the aforementioned collaborative processing, the impurity sensing component undertakes the crucial steps of impurity information acquisition and calibration mapping, while the probe processing unit undertakes the fusion calculation step coupled with the ultrasonic measurement link. Therefore, in the system-level functional description, it can be stated that the impurity sensing component acquires impurity characteristic parameters. The results are then fused with the ultrasonic attenuation difference component by the probe processing unit.

[0079] Furthermore, as another optional implementation, it is possible to... The value of and The calculation is encapsulated as an interface calculation process between the impurity sensing component and the probe processing unit. Specifically, the probe processing unit sends the peak amplitude pairs of the selected candidate propagation time combinations to the impurity sensing component, which then completes the calculation. Calculation of the item and its relation to Common output impurity characteristic parameters The probe processing unit is provided with the information; in this optional implementation, the impurity sensing component functionally directly outputs impurity characteristic parameters. The probe processing unit maintains the same workflow for determining subsequent calibration values, common-mode calibration, cross-frequency consistency screening, and flow calculation, thereby enabling the acquisition of impurity characteristic parameters. The main point of view is more intuitive.

[0080] It should be noted that the embodiments of the present invention have better implementability and are not intended to limit the present invention in any way. Any person skilled in the art may use the above-disclosed technical content to change or modify it into equivalent effective embodiments. However, any modifications or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for ultrasonic flow measurement of a fluid containing impurities with a dual-coupled smart sensor probe, the method comprising: Includes the following steps: S1. A dual-coupled intelligent sensing probe is installed on the outer wall of the pipe to be tested, which carries fluid containing impurities. The dual-coupled intelligent sensing probe includes at least an upstream ultrasonic transducer, a downstream ultrasonic transducer, an impurity sensing component, and a probe processing unit. The impurity sensing component includes an intelligent sensing element. The probe processing unit and the impurity sensing component constitute an intelligent sensing system. S2, at the first center frequency With the second center frequency Bidirectional propagation time measurements were performed separately to obtain the downstream propagation time at the first center frequency. With the time of reverse propagation and downstream propagation time at the second center frequency With the time of reverse propagation ; S3. The probe processing unit extracts the reflected signal segment corresponding to the reflection from the wall of the pipe under test from the received signal and determines the coupling state parameters. The impurity characteristic parameters are obtained by the impurity sensing component. ; S4, the probe processing unit, based on the coupling state parameters... Determine the coupling common-mode correction amount And based on the impurity characteristic parameters With dual-frequency common-mode differential components Determine the impurity common-mode correction amount corresponding to the first center frequency. And the common-mode correction amount of impurities corresponding to the second center frequency ,in: S5. determining, by the probe processing unit, the downstream propagation time upstream propagation time downstream propagation time upstream propagation time performing common mode decoupling correction, resulting in: S6. When a set of candidate propagation times exists, the probe processing unit combines the elements of the set of candidate propagation times to form multiple candidate propagation time combinations, and selects a candidate propagation time combination that satisfies the cross-frequency consistency constraint from the multiple candidate propagation time combinations, wherein the cross-frequency consistency constraint includes at least: wherein, is a preset threshold value; S7. selecting, by the probe processing unit, based on the cross-frequency consistency constraint with calculating a volume flow and outputting the volume flow .

2. The method for measuring the ultrasonic flow rate of fluids containing impurities using a dual-coupled intelligent sensing probe according to claim 1, characterized in that, The volumetric flow satisfies the following calculation formula: in, The inner diameter of the pipe. The sound path length, For installation angle, For the cross-sectional area of ​​circulation, The average flow velocity, Pi is a constant. and These refer to the corrected reverse propagation time and the corrected forward propagation time selected by the cross-frequency consistency constraint in step S7 of claim 1, respectively.

3. The method for measuring the ultrasonic flow rate of fluids containing impurities using a dual-coupled intelligent sensing probe according to claim 1, characterized in that, In step S6, when multiple candidate propagation time combinations exist, the candidate propagation time combination is selected by minimizing the consistency loss function, and the consistency loss function... satisfy: ； wherein, , , is a preset weight, and are normalized correlation coefficients of the cross-correlation peaks corresponding to the first center frequency and the second center frequency, respectively.

4. The method for measuring the ultrasonic flow rate of fluid containing impurities using a dual-coupled intelligent sensing probe according to claim 1, characterized in that, The candidate propagation time set is obtained as follows: An effective window is set for the received signal, and within the effective window, a cross-correlation operation is performed on the reference templates corresponding to the received signal and the excitation signal, extracting the first... The time delay corresponding to each local peak is used as a candidate propagation time, and candidate propagation time subsets are established for downstream and upstream, and for the first center frequency and the second center frequency, respectively. These candidate propagation time subsets constitute a candidate propagation time set. It is a preset positive integer.

5. The method for measuring the ultrasonic flow rate of fluid containing impurities using a dual-coupled intelligent sensing probe according to claim 1, characterized in that, The coupling state parameters in step S3 The determination includes: extracting the first reflected signal segment and the second reflected signal segment from the received signal, and calculating the energy of the first reflected signal segment respectively. Energy of the second reflected signal segment The coupling state parameters are determined according to the following formula. : And the energy satisfy: in, For the corresponding reflected signal segment Amplitude at each sampling point, This represents the number of sampling points for the corresponding reflected signal segment.

6. The method for measuring the ultrasonic flow rate of fluid containing impurities using a dual-coupled intelligent sensing probe according to claim 5, characterized in that, The coupling common-mode correction amount By regard to the coupling state parameters Piecewise monotonic mapping It is determined that the segmented monotonic mapping satisfies the application of upper and lower bound constraints on the mapping values ​​of each segment endpoint.

7. The method for measuring the ultrasonic flow rate of impurity-containing fluid using a dual-coupled intelligent sensing probe according to claim 1, characterized in that, The impurity characteristic parameters The quantity obtained by calibration of the turbidity signal output by the intelligent sensing element Together with the ultrasonic attenuation difference component, the ultrasonic attenuation difference component is determined by the cross-correlation peak amplitude and satisfies: in, , , These are preset parameters. It is the natural logarithm function; The average of the peak amplitudes of the downstream cross-correlation and the peak amplitudes of the upstream cross-correlation corresponding to the selected candidate propagation time combination described in step S6 of claim 1 at the first center frequency. It is the average of the peak amplitudes of the downstream cross-correlation and the peak amplitudes of the upstream cross-correlation corresponding to the selected candidate propagation time combination at the second center frequency.

8. The method for measuring the ultrasonic flow rate of impurity-containing fluid using a dual-coupled intelligent sensing probe according to claim 1, characterized in that, The common-mode correction amount of impurities Common-mode correction amount with the impurities Two-dimensional constraint lookup table mapping Output, and satisfy the inter-frequency difference constraint: in, For preset coefficients, This is a preset threshold.

9. The method for measuring the ultrasonic flow rate of fluids containing impurities using a dual-coupled intelligent sensing probe according to claim 1, characterized in that, The dual-coupled smart sensing probe includes two measurement acoustic paths with different sound paths, denoted as follows: The probe processing unit performs steps S2 to S6 of claim 1 on the two measurement acoustic paths respectively to obtain the corresponding values ​​of the two measurement acoustic paths. and The equivalent flow-direction sensitive component used to calculate the volumetric flow rate is determined by weighted least squares.

10. The method for measuring the ultrasonic flow rate of impurity-containing fluid using a dual-coupled intelligent sensing probe according to claim 7, characterized in that, It also includes a sensor degradation step: when the turbidity signal is unavailable or exceeds a preset range, the probe processing unit uses the ultrasonic attenuation difference component to replace the turbidity signal in the impurity characteristic parameters. The determination is made while keeping the calculation process of steps S4 to S7 of claim 1 unchanged.

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