Flow metering method of non-full pipe electromagnetic flowmeter

Abstract

The invention relates to the technical field of flow metering, in particular to a flow metering method of a non-full-pipe electromagnetic flowmeter, which comprises the following steps: collecting a laser pulse signal emitted by a laser liquid level meter in the non-full-pipe electromagnetic flowmeter and a received echo signal; the fluid flow velocity is obtained through electrodes at preset heights of the inner wall of the pipeline in real time; initial matching echo signal points of all pulse signal points in the laser pulse signals are obtained, and the Reynolds number of fluid in the pipeline at the collection moment of all the pulse signal points is obtained; obtaining the disorder degree of each pulse signal point; obtaining the local disorder aggregation degree of each pulse signal point through the disorder degree distribution of preset adjacent pulse signal points of each pulse signal point, obtaining the correlation degree of each pulse signal point, and optimizing the disorder degree; screening each mismatched pulse signal point and re-matching an echo signal point for the mismatched pulse signal point; and fluid flow in the pipeline is obtained. The invention aims to improve the flow metering precision of the non-full pipe electromagnetic flowmeter.

Description

Technical Field

[0001] The present application relates to the technical field of flow measurement, and in particular to a flow measurement method for a partially full-tube electromagnetic flowmeter. Background Art

[0002] In practical applications, liquids often flow in partially filled pipes in scenarios such as urban drainage systems, industrial wastewater discharge pipes, and agricultural irrigation channels. However, traditional electromagnetic flowmeters are primarily designed for fully filled pipes. Electrodes are installed along the horizontal diameter of the pipe. When a conductive fluid cuts through magnetic lines of force in a magnetic field, an induced electromotive force is generated perpendicular to the magnetic field and the flow direction. This is used to calculate the current flow rate. In a partially filled pipe, the upper portion of the pipe is air, while the lower portion is liquid. The flow of the liquid is irregular, making it impossible to accurately measure the relationship between the induced electromotive force and the flow rate.

[0003] Traditional electromagnetic flowmeters are widely used in industrial fluid measurement, but their principle is not suitable for measuring conductive liquids in partially filled pipes. In partially filled pipes, measurement accuracy is significantly reduced due to fluid level fluctuations and complex flow patterns, making it impossible to meet the demand for precise flow monitoring in industrial production. Summary of the Invention

[0004] In view of the above, it is necessary to provide a flow measurement method for a partially full pipe electromagnetic flowmeter, which improves the flow measurement accuracy of the partially full pipe electromagnetic flowmeter compared to traditional flow measurement methods.

[0005] The flow measurement method of a non-full pipe electromagnetic flowmeter of the present application adopts the following technical solution: One embodiment of the present application provides a flow measurement method for a partially full-pipe electromagnetic flowmeter, the method comprising the following steps: The laser pulse signal emitted by the laser level meter in the partially filled electromagnetic flowmeter and the received echo signal are collected within a preset time period; the fluid flow rate is obtained in real time through electrodes at preset heights on the inner wall of the pipeline; In terms of timing, the echo signal points in the echo signal with the same sequence number as the pulse signal points in the laser pulse signal are recorded as initial matching echo signal points. The initial liquid level in the pipeline at the time of each pulse signal point acquisition is obtained by the time difference between each pulse signal point and its initial matching echo signal point. The Reynolds number of the fluid in the pipeline at the time of each pulse signal point acquisition is obtained by the flow velocity collected by the electrode at the initial liquid level. The attenuated signal amplitude of each pulse signal point is obtained by comparing the signal amplitude of each pulse signal point with its initial matching echo signal point and the attenuated signal amplitude to obtain the disorder degree of each pulse signal point; The local disorder aggregation degree of each pulse signal point is obtained by the distribution of the disorder degree of the preset neighboring pulse signal points of each pulse signal point; the correlation degree of each pulse signal point is obtained by comparing the initial liquid level height difference of each pulse signal point compared with the adjacent pulse signal points and the Reynolds number, and the disorder degree is optimized in combination with the local disorder aggregation degree; the mismatched pulse signal points are screened from all pulse signal points by distributing the optimization results of the disorder degree of all pulse signal points; the matching echo signal points of each mismatched pulse signal point are re-obtained by combining the optimized disorder degree with the particle swarm algorithm; the fluid flow in the pipeline at the time of acquisition of each pulse signal point is obtained by finally matching each pulse signal point with the echo signal point to which it is matched.

[0006] In one embodiment, when obtaining the Reynolds number of the fluid in the pipeline at the time of collection of each pulse signal point, the flow rate of the fluid in the Reynolds number calculation formula is: the average value of the flow rates collected by all electrodes at the initial liquid level height corresponding to each pulse signal point.

[0007] In one embodiment, obtaining the attenuated signal amplitude of each pulse signal point includes: The expression of the signal amplitude after attenuation of each pulse signal point is: Where, Indicates the signal amplitude after the qth pulse signal point is attenuated; Represents the signal amplitude of the qth pulse signal point; represents an exponential function with a natural constant as the base; α represents the attenuation coefficient of the pulse signal in the medium; It represents the distance between the liquid surface and the laser level meter calculated by the qth pulse signal point and its initial matching echo signal point; The method for obtaining α is as follows: the signal amplitude of the first pulse signal point and its initial matching echo signal point, as well as the distance between the liquid surface and the laser level meter calculated by the first pulse signal point and its initial matching echo signal point are substituted into .

[0008] In one embodiment, the process of obtaining the disorder degree is as follows: The difference between the signal amplitude of the initial matching echo signal point of each pulse signal point and the attenuated signal amplitude is calculated; the confusion degree is the ratio of the difference to the signal amplitude of each pulse signal point.

[0009] In one embodiment, the expression of the local disorder aggregation degree is: Where, represents the local disorder concentration degree of the qth pulse signal point; U represents the number of preset neighboring pulse signal points of the qth pulse signal point; 、 They respectively represent the confusion degree of the preset u-th and u+1-th neighboring pulse signal points of the q-th pulse signal point; ε represents a preset positive number; Indicates the absolute value operation.

[0010] In one embodiment, the process of obtaining the association degree is as follows: Calculating the deviation value of the initial liquid level height between each pulse signal point and each adjacent pulse signal point, and counting the maximum value of the deviation values ​​between each pulse signal point and all adjacent pulse signal points; Calculating a ratio of a normalized value of the Reynolds number to a normalized value of the maximum value, and calculating a difference between the ratio and 1; The correlation degree is the reciprocal of the sum of the difference value and a preset positive number.

[0011] In one embodiment, the process of optimizing the disorder degree is: Obtaining a disorder degree optimization factor for each pulse signal point through the correlation degree and the local disorder concentration degree; The sum of the chaos degree optimization factor and 1 is calculated, and the product of the sum and the chaos degree of each pulse signal point is used as the optimized chaos degree of each pulse signal point.

[0012] In one embodiment, the disorder optimization factor is a normalized value of the product of the correlation degree and the local disorder concentration degree.

[0013] In one embodiment, the process of screening mismatched pulse signal points from all pulse signal points is as follows: According to the optimized confusion degree of all pulse signal points, all pulse signal points are divided into two categories, the average of the optimized confusion degree of all pulse signal points in each category is calculated, and each pulse signal point in the category with the largest average value is used as a mismatched pulse signal point.

[0014] In one embodiment, in the process of reacquiring each matching echo signal point of each mismatched pulse signal point, the fitness value of each particle in the particle swarm algorithm is the inverse of the sum of the optimized confusion degrees of all pulse signal points under each particle.

[0015] This application has at least the following beneficial effects: This application takes into account the different fluid flow rates at different heights inside the pipeline. By installing transverse electrodes at different heights inside the pipeline, the fluid flow rate in the pipeline can be measured more accurately, which is beneficial to improving the accuracy of flow measurement; by calculating the Reynolds number, the flow state of the fluid can be judged; by calculating the disorder degree, the matching error between the pulse signal point in the laser pulse signal and the echo signal point in the echo signal can be quantified, helping to identify the mismatched pulse signal point, so as to dynamically adjust the signal matching strategy according to the size of the disorder degree; by calculating the distribution of the disorder degree of the neighboring pulse signal points of each pulse signal point, the local disorder aggregation degree is calculated, which helps to identify the mismatch phenomenon caused by liquid level fluctuations. Through local feature recognition, it can More accurately screen out mismatched pulse signal points and reduce misjudgments caused by environmental interference; obtain the correlation between liquid level changes and Reynolds numbers to obtain the correlation between each pulse signal point, which can effectively avoid abnormal confusion caused by environmental interference; optimize the confusion by local confusion aggregation and correlation, which can more accurately reflect the signal mismatch situation; through the distribution of optimized confusion, more accurately screen out mismatched pulse signal points, through the optimized confusion, combined with the particle swarm algorithm, re-match the echo signal point for each mismatched pulse signal point, improve the signal matching effect, and measure the flow rate through the optimized matching results, thereby improving the flow measurement accuracy of the non-full pipe electromagnetic flowmeter. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present application or the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0017] Figure 1 A flow chart of the steps of a flow measurement method for a partially full pipe electromagnetic flowmeter provided in this application; Figure 2 This is a schematic diagram of the installation position of the lateral electrode; Figure 3 Schematic diagram of the optimization process of disorder degree; Figure 4 Schematic diagram of the matching process between pulse signal points and echo signal points. DETAILED DESCRIPTION

[0018] In the description of the embodiments of this application, words such as "exemplary," "or," and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary," "or," and "for example" is intended to present the relevant concepts in a concrete manner.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application relates. The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. It should be understood that, unless otherwise indicated, " / " represents or.

[0020] It should also be noted that the terms "first" and "second" in this application are used to distinguish similar objects, rather than to describe a specific order or sequence.

[0021] The following describes in detail a specific solution of a flow measurement method for a non-full pipe electromagnetic flowmeter provided by the present application with reference to the accompanying drawings.

[0022] An embodiment of the present application provides a flow measurement method for a non-full pipe electromagnetic flowmeter. Specifically, the following flow measurement method for a non-full pipe electromagnetic flowmeter is provided. Figure 1 , the method comprises the following steps: Step 1: Collect the laser pulse signal emitted by the laser level meter in the partially full pipe electromagnetic flowmeter and the received echo signal within a preset time period; obtain the fluid flow rate in real time through electrodes at preset heights on the inner wall of the pipeline.

[0023] The partially filled pipe electromagnetic flowmeter used in this application features a high-precision laser level meter mounted on the integrated inductor coil, vertically above the sensor's center. Its transmitter is precisely aligned vertically downward into the pipe. Furthermore, a pair of corrosion-resistant, highly conductive transverse electrodes, made of platinum-plated stainless steel, are symmetrically embedded horizontally at predetermined heights along the pipe's inner wall.

[0024] In this embodiment, the preset heights refer to 1 / 2, 1 / 4 and 1 / 8 of the height of the inner wall of the pipe, and a total of 3 pairs of transverse electrodes are embedded. The installation height and installation quantity of the transverse electrodes are manually preset. The implementer can set the installation height and installation quantity of the transverse electrodes according to the actual situation. This application does not impose any special restrictions. Figure 2 As shown, Figure 2In the figure, 1 represents a laser level meter, 2 represents a pair of transverse electrodes at 1 / 2 height, 3 represents a pair of transverse electrodes at 1 / 4 height, 4 represents a pair of transverse electrodes at 1 / 8 height, and 5 represents a grounding electrode.

[0025] A laser level meter is an intelligent sensor that uses a laser beam to measure the distance to the liquid surface. Using advanced laser pulse ranging technology, the laser level meter measures the time difference between emitting laser light and receiving reflected light to calculate the distance from the laser level meter to the liquid surface, and thus the liquid level. Within a preset time period, the laser pulse signal emitted by the laser level meter in a partially filled electromagnetic flowmeter and the received echo signal are collected.

[0026] In this embodiment, the length of the preset time period is 1s, and the emission frequency of the laser level meter is 100Hz. The length of the preset time period and the emission frequency of the laser level meter are preset manually, and the implementer can set them according to actual conditions. This application does not impose any special restrictions.

[0027] When the liquid flows in the pipeline, the transverse electrodes located below the liquid level capture the induced electromotive force generated by the fluid cutting the magnetic lines of force based on the principle of electromagnetic induction. Since the fluid flow rate at different heights is different, the measurement values ​​of multiple pairs of transverse electrodes can reflect the vertical distribution characteristics of the flow rate. Therefore, in this application, the transverse electrodes deployed by the non-full pipe electromagnetic flowmeter are used to collect the induced electromotive force in real time, and the flow rate of the fluid is obtained based on the induced electromotive force and Faraday's law of electromagnetic induction. At the time of collecting each pulse signal point in the laser pulse signal, each pair of transverse electrodes below the liquid level can obtain the flow rate of the fluid. Among them, obtaining the flow rate of the fluid based on the induced electromotive force and Faraday's law of electromagnetic induction is a well-known technology and will not be repeated in this application. Each laser pulse in the laser pulse signal is recorded as each pulse signal point, and each laser pulse in the echo signal is recorded as each echo signal point.

[0028] Step 2: Obtain the initial matching echo signal point of each pulse signal point in the laser pulse signal, and obtain the Reynolds number of the fluid in the pipeline at the time of acquisition of each pulse signal point; obtain the disorder degree of each pulse signal point; optimize the disorder degree by distributing the disorder degrees of preset neighboring pulse signal points of each pulse signal point, and comparing the initial liquid level height difference of each pulse signal point compared with the adjacent pulse signal points with the Reynolds number; filter out each mismatched pulse signal point from all pulse signal points, and re-obtain each matching echo signal point of each mismatched pulse signal point.

[0029] Traditional algorithms typically use the time difference between the time a smart sensor transmits a laser pulse signal and the time it receives the echo as the laser pulse's echo time. Combined with the laser pulse's propagation velocity, this process is used to calculate the laser pulse's propagation distance. This process allows for precise measurement of solids that remain stable. However, in flow measurement scenarios using electromagnetic flowmeters with partially filled pipes, the fluid's surface fluctuates due to the characteristics of fluid flow. This results in an unstable echo time, which in turn affects the smart sensor's measurement accuracy of the liquid level, and consequently, the accuracy and efficiency of subsequent flow measurement.

[0030] Step 2.1, in terms of timing, the echo signal points in the echo signal with the same serial number as the pulse signal points in the laser pulse signal are recorded as initial matching echo signal points, and the initial liquid level height in the pipeline at the time of collection of each pulse signal point is obtained through the time difference between each pulse signal point and its initial matching echo signal point; the Reynolds number of the fluid in the pipeline at the time of collection of each pulse signal point is obtained through the flow velocity collected by the electrode at the initial liquid level height.

[0031] The echo signal points in the echo signal with the same serial number as the pulse signal points in the laser pulse signal are recorded as the initial matching echo signal points of each pulse signal point, wherein the pulse signal points in the laser pulse signal and the echo signal points in the echo signal are numbered in time sequence. The time difference between each pulse signal point and its initial matching echo signal point is recorded as each initial echo time. The initial propagation distance of each pulse signal point is obtained by comparing each initial echo time with the propagation speed of the laser pulse signal. The difference between the inner diameter of the pipeline and each initial propagation distance is used as the initial liquid level height in the pipeline at the time of acquisition of each pulse signal point, which is used to determine which transverse electrodes are enabled. The key to the distance measurement of the laser level meter is to accurately find the echo signal point corresponding to the pulse signal point in the laser pulse signal. The propagation speed of the laser pulse signal can be obtained through prior knowledge.

[0032] For the fluid, in this application, the density and dynamic viscosity of the fluid are obtained in real time by using the densitometer and viscometer deployed in the laser level meter, and the average of the flow velocities obtained by all pairs of transverse electrodes below the initial liquid level height at the time of each pulse signal point acquisition is obtained. The Reynolds number of the fluid in the pipeline at the time of each pulse signal point acquisition is obtained through the density of the fluid, the average flow velocity, the characteristic length of the pipeline, the dynamic viscosity and the kinematic viscosity, wherein the characteristic length of the pipeline is the inner diameter of the pipeline, and the kinematic viscosity can be obtained through the dynamic viscosity and density. The specific method of obtaining the kinematic viscosity through the dynamic viscosity and density is a well-known technology and will not be described in detail in this application. The Reynolds number is a dimensionless number in fluid mechanics that characterizes the flow state of the fluid, such as laminar flow, transitional flow or turbulent flow. It is used to quantify the relative strength of the inertial force and the viscous force of the fluid. The larger the Reynolds number, the stronger the dominant force of the inertial force in the fluid, and the more the flow trend tends to turbulence, that is, chaos and strong mixing; the smaller the Reynolds number, the more the fluid tends to laminar flow, that is, smooth and stratified flow. The specific calculation method of the Reynolds number is a well-known technology and will not be described in detail in this application.

[0033] Step 2.2, obtain the signal amplitude of each pulse signal point after attenuation through the relationship between the signal amplitude of each pulse signal point and the transmission distance, and obtain the disorder degree of each pulse signal point by comparing the signal amplitude of each pulse signal point with its initial matching echo signal point and the attenuated signal amplitude.

[0034] The relationship between the signal amplitude of each pulse signal point and the transmission distance is used to obtain the signal amplitude of each pulse signal point after attenuation. The expression is: Where, Indicates the signal amplitude after the qth pulse signal point is attenuated; Represents the signal amplitude of the qth pulse signal point; represents an exponential function with a natural constant as the base; α represents the attenuation coefficient of the pulse signal in the medium; It represents the distance between the liquid surface and the laser level meter calculated by the qth pulse signal point and its initial matching echo signal point, and is specifically obtained by the time difference between the qth pulse signal point and its initial matching echo signal point, and the propagation speed of the laser pulse signal. In this embodiment, the calculation method of α is: substitute the signal amplitude of the first pulse signal point into , substitute the signal amplitude of the initial matching echo signal point of the first pulse signal point into , substitute the distance between the liquid surface and the laser level meter calculated by the first pulse signal point and its initial matching echo signal point into ,pass Calculate the value of α.

[0035] Furthermore, by comparing the signal amplitude of each pulse signal point with its initial matching echo signal point and the attenuated signal amplitude, the disorder degree of each pulse signal point is obtained, and the expression is: Where, Indicates the disorder degree of the qth pulse signal point; Represents the signal amplitude of the initial matching echo signal point of the qth pulse signal point; Indicates the signal amplitude after the qth pulse signal point is attenuated; Represents the signal amplitude of the qth pulse signal point; Indicates the absolute value operation.

[0036] It should be noted that the greater the difference between the signal amplitude of the initial matching echo signal point of the qth pulse signal point and the attenuated signal amplitude, the lower the degree of match between the qth pulse signal point and its initial matching echo signal point. The greater the degree of confusion, the lower the degree of match between the qth pulse signal point and its initial matching echo signal point, and the lower the accuracy of the calculated initial echo time. The pulse signal point and the echo signal point should be re-matched. The smaller the degree of confusion, the higher the degree of match between the pulse signal point and the echo signal point, and the higher the accuracy of the calculated initial echo time.

[0037] Step 2.3, obtain the local disorder concentration of each pulse signal point through the disorder distribution of the preset neighboring pulse signal points of each pulse signal point; obtain the correlation of each pulse signal point by comparing the initial liquid level height difference of each pulse signal point compared with the adjacent pulse signal points and the Reynolds number, and optimize the disorder degree in combination with the local disorder concentration.

[0038] The confusion factor reflects the matching status of a pulse signal point and an echo signal point by measuring the attenuation of the pulse signal point's signal amplitude. However, because the confusion factor reflects the matching status of a single pulse signal point, using it directly to measure the matching effect of a pulse signal point is less robust. This is because when the echo signal point acquisition process is affected by environmental interference, causing the echo signal amplitude to deviate from the predicted amplitude, the confusion factor of the pulse signal point may be higher, but the matching between the pulse signal point and the echo signal point may not be confused.

[0039] Based on the above analysis, the present application optimizes the disorder degree of each pulse signal point by comparing the initial liquid level difference and the Reynolds number of each pulse signal point compared with the adjacent pulse signal points through the disorder degree distribution of the preset neighboring pulse signal points of each pulse signal point. The specific process is as follows: (1) The local disorder concentration of each pulse signal point is obtained by the disorder distribution of the preset neighboring pulse signal points of each pulse signal point.

[0040] Regarding the phenomenon of mismatching between pulse signal points and echo signal points caused by liquid level fluctuations, when a pulse signal point has a mismatch, its adjacent pulse signal points will often also have mismatches. Therefore, the distribution of the disorder degree has a certain local concentration. Therefore, the local disorder concentration of each pulse signal point is obtained by the disorder degree distribution of the preset neighboring pulse signal points of each pulse signal point. The expression is: Where, represents the local disorder concentration degree of the qth pulse signal point; U represents the number of preset neighboring pulse signal points of the qth pulse signal point; 、 They respectively represent the disorder degree of the u-th and u+1-th neighboring pulse signal points of the q-th pulse signal point; ε represents a preset positive number used to avoid the denominator being 0. The value of ε is preset by the implementer and can be set by the implementer. In this embodiment, the value of ε is 0.01; Indicates the absolute value operation.

[0041] In this embodiment, the value of U is 10. The value of U is preset manually and can be set by the implementer. This application does not impose any special restrictions.

[0042] (2) Obtaining the correlation degree of each pulse signal point by comparing the initial liquid level difference of each pulse signal point with the adjacent pulse signal point and the Reynolds number.

[0043] Furthermore, by comparing the initial liquid level difference between each pulse signal point and the adjacent pulse signal point and the Reynolds number, the correlation degree of each pulse signal point is obtained, and the expression is: Where, Indicates the correlation degree of the qth pulse signal point; represents the normalized value of the Reynolds number of the fluid in the pipeline at the time of acquisition of the qth pulse signal point; calculates the deviation value of the initial liquid level height between the qth pulse signal point and each of its adjacent pulse signal points, represents the normalized value of the maximum value of the deviation values ​​between the qth pulse signal point and all its adjacent pulse signal points; σ represents a preset positive number used to avoid the denominator being 0. The value of σ is manually preset and can be set by the implementer. In this embodiment, the value of σ is 0.01; Indicates the absolute value operation.

[0044] In this embodiment, the deviation value between the initial liquid level heights is the absolute value of the difference.

[0045] In this embodiment, the Sigmoid function is used to obtain the normalized value of the Reynolds number and the normalized value of the maximum value respectively. The Sigmoid function is a well-known technology and will not be described in detail in this application.

[0046] It should be noted that the larger the Reynolds number, the stronger the dominance of inertial forces in the fluid, and the more turbulent the flow tends to be. This means that greater fluid flow fluctuations and greater liquid level fluctuations occur. The closer the normalized Reynolds number is to the normalized value of the maximum liquid level height difference, the greater the actual level fluctuations are due to the fluid's flow properties, rather than interference with the echo signal. Optimizing the level of confusion by calculating the correlation can avoid situations where high levels of confusion are caused by environmental interference with the echo signal.

[0047] (3) The disorder degree of each pulse signal point is optimized by the correlation degree of each pulse signal point and the local disorder concentration degree.

[0048] Furthermore, the disorder optimization factor of each pulse signal point is obtained through the correlation degree of each pulse signal point and the local disorder aggregation degree. Specifically, the normalized value of the product of the correlation degree of each pulse signal point and the local disorder aggregation degree is used as the disorder optimization factor of each pulse signal point.

[0049] In this embodiment, the Min-Max normalization method is used to obtain the normalized value of the product of the correlation degree of each pulse signal point and the local disorder aggregation degree. The Min-Max normalization method is a well-known technology and will not be described in detail in this application.

[0050] Furthermore, the disorder degree of each pulse signal point is optimized by the disorder degree optimization factor of each pulse signal point to obtain the optimized disorder degree of each pulse signal point, which is expressed as: Where, Indicates the optimized disorder degree of the qth pulse signal point; Indicates the disorder degree of the qth pulse signal point; The optimization factor of the disorder degree of the qth pulse signal point is shown in the following diagram: Figure 3 shown.

[0051] Step 2.4, through the distribution of the optimization results of the disorder degree of all pulse signal points, the mismatched pulse signal points are screened from all pulse signal points; through the optimized disorder degree combined with the particle swarm algorithm, the matching echo signal points of each mismatched pulse signal point are re-obtained.

[0052] According to the optimized confusion degree of all pulse signal points, all pulse signal points are divided into two categories, the average of the optimized confusion degree of all pulse signal points in each category is calculated, and each pulse signal point in the category with the largest average value is used as a mismatched pulse signal point.

[0053] In this embodiment, the K-Means algorithm is used to divide all pulse signal points into two categories, and the absolute value of the difference between the optimized disorder degrees of the pulse signal points is used as the metric distance in the K-Means algorithm. The K-Means algorithm is a well-known technology and will not be described in detail in this application. As other implementation methods, on the basis of being able to divide all pulse signal points into two categories, the implementer can adopt other existing technologies, such as the Otsu threshold segmentation algorithm, iterative threshold segmentation, etc., and this application does not impose any special restrictions.

[0054] Furthermore, the present application adopts a particle swarm algorithm to re-match the echo signal points of each mismatched pulse signal point. The number of particles in the particle swarm algorithm is 100, the dimension of the particles is equal to the number of mismatched pulse signal points, the inertia weight is 0.9, the cognitive coefficient and the social coefficient are both 1.5, and the fitness value of each particle is the inverse of the sum of the optimized disorder of all pulse signal points under each particle. The larger the fitness value, the better the matching effect between the pulse signal point and the echo signal point. In the present application, the particle with the largest fitness value is selected as the final matching result to obtain each matching echo signal point for each mismatched pulse signal point. Among them, the number of particles is 100, the inertia weight is 0.9, and the cognitive coefficient and the social coefficient are both 1.5. It is only an embodiment of the present application. The implementer can set the specific value according to the actual situation, and the present application does not impose any special restrictions. The schematic diagram of the matching process of pulse signal points and echo signal points is shown in the figure. Figure 4 shown.

[0055] Step 3: Obtain the fluid flow rate in the pipeline at the time of acquisition of each pulse signal point by matching each pulse signal point with the echo signal point.

[0056] According to each pulse signal point in the laser pulse signal sequence and its final matching echo signal point, the liquid level height in the pipeline at the time of collection of each pulse signal point can be obtained. The cross-sectional area of ​​the fluid in the pipeline at the time of collection of each pulse signal point can be calculated through the liquid level height and the inner diameter of the pipeline. Among them, calculating the cross-sectional area of ​​the fluid in the pipeline at the time of collection of each pulse signal point through the liquid level height and the inner diameter of the pipeline is a well-known technology and will not be repeated in this application.

[0057] Furthermore, the average value of the fluid flow rate obtained by all pairs of transverse electrodes at the liquid level height in the pipeline at the time of each pulse signal point acquisition is extracted, and the product of the average value and the cross-sectional area of ​​the fluid in the pipeline at the time of each pulse signal point acquisition is taken as the fluid flow rate in the pipeline at the time of each pulse signal point acquisition.

[0058] In summary, the present application takes into account the different fluid flow rates at different heights inside the pipeline. By installing transverse electrodes at different heights inside the pipeline, the fluid flow rate in the pipeline can be measured more accurately, which is beneficial to improving the accuracy of flow measurement; by calculating the Reynolds number, the flow state of the fluid can be judged; by calculating the degree of disorder, the matching error between the pulse signal point in the laser pulse signal and the echo signal point in the echo signal can be quantified, helping to identify the mismatched pulse signal point, so as to dynamically adjust the signal matching strategy according to the degree of disorder; by calculating the distribution of the degree of disorder of the neighboring pulse signal points of each pulse signal point, the local disorder aggregation degree is calculated, which helps to identify the mismatch phenomenon caused by liquid level fluctuation, and recognize the local feature , which can more accurately screen out mismatched pulse signal points and reduce misjudgments caused by environmental interference; through the correlation between liquid level changes and Reynolds numbers, the correlation degree of each pulse signal point is obtained, which can effectively avoid abnormal confusion caused by environmental interference; through the optimization of local confusion aggregation and correlation, the confusion degree can be more accurately reflected. The distribution of the optimized confusion degree can more accurately screen out mismatched pulse signal points, and through the optimized confusion degree, combined with the particle swarm algorithm, the echo signal point is re-matched for each mismatched pulse signal point, which improves the signal matching effect, and the flow measurement is performed through the optimized matching results, which improves the flow measurement accuracy of the non-full pipe electromagnetic flowmeter.

[0059] The flowcharts and block diagrams in the accompanying drawings show the possible implementation architectures, functions and operations of the systems, methods and computer program products according to the embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, program segment or part of the code, and the module, program segment or part of the code contains one or more executable instructions for implementing the specified logical functions. In some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, or they can sometimes be executed in the opposite order, which can depend on the functions involved. In the descriptions corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different boxes can also occur in an order different from that disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps can actually be executed substantially in parallel, or they can sometimes be executed in the opposite order, which can depend on the functions involved. Each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented by a dedicated hardware-based system that performs the specified function or action, or may be implemented by a combination of dedicated hardware and computer instructions.

[0060] It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and that the present application can be implemented in other specific forms without departing from the basic characteristics of the present application. Therefore, from all perspectives, the above embodiments of the present application should be regarded as exemplary and non-restrictive.

Claims

1. A flow measurement method for a partially full tube electromagnetic flowmeter, characterized in that: The method comprises the following steps: The laser pulse signal emitted by the laser level meter in the partially filled electromagnetic flowmeter and the received echo signal are collected within a preset time period; the fluid flow rate is obtained in real time through electrodes at preset heights on the inner wall of the pipeline; In terms of timing, the echo signal points in the echo signal with the same sequence number as the pulse signal points in the laser pulse signal are recorded as initial matching echo signal points. The initial liquid level in the pipeline at the time of each pulse signal point acquisition is obtained by the time difference between each pulse signal point and its initial matching echo signal point. The Reynolds number of the fluid in the pipeline at the time of each pulse signal point acquisition is obtained by the flow velocity collected by the electrode at the initial liquid level. The attenuated signal amplitude of each pulse signal point is obtained by comparing the signal amplitude of each pulse signal point with its initial matching echo signal point and the attenuated signal amplitude to obtain the disorder degree of each pulse signal point; The local disorder aggregation degree of each pulse signal point is obtained by the distribution of the disorder degree of the preset neighboring pulse signal points of each pulse signal point; the correlation degree of each pulse signal point is obtained by comparing the initial liquid level height difference of each pulse signal point compared with the adjacent pulse signal points and the Reynolds number, and the disorder degree is optimized in combination with the local disorder aggregation degree; the mismatched pulse signal points are screened from all pulse signal points by distributing the optimization results of the disorder degree of all pulse signal points; the matching echo signal points of each mismatched pulse signal point are re-obtained by combining the optimized disorder degree with the particle swarm algorithm; the fluid flow in the pipeline at the time of acquisition of each pulse signal point is obtained by finally matching each pulse signal point with the echo signal point to which it is matched.

2. The flow measurement method of a partially full tube electromagnetic flowmeter according to claim 1, characterized in that: When obtaining the Reynolds number of the fluid in the pipeline at the time of collecting each pulse signal point, the flow rate of the fluid in the calculation formula of the Reynolds number is: the average value of the flow rates collected by all electrodes at the initial liquid level height corresponding to each pulse signal point.

3. The flow measurement method of a partially full tube electromagnetic flowmeter according to claim 1, characterized in that: The obtaining of the attenuated signal amplitude of each pulse signal point includes: The expression of the signal amplitude after attenuation of each pulse signal point is: Where, Indicates the signal amplitude after the qth pulse signal point is attenuated; Represents the signal amplitude of the qth pulse signal point; represents an exponential function with a natural constant as the base; α represents the attenuation coefficient of the pulse signal in the medium; It represents the distance between the liquid surface and the laser level meter calculated by the qth pulse signal point and its initial matching echo signal point; The method for obtaining α is as follows: the signal amplitude of the first pulse signal point and its initial matching echo signal point, as well as the distance between the liquid surface and the laser level meter calculated by the first pulse signal point and its initial matching echo signal point are substituted into .

4. The flow measurement method of a partially full tube electromagnetic flowmeter according to claim 1, characterized in that: The process of obtaining the disorder degree is as follows: The difference between the signal amplitude of the initial matching echo signal point of each pulse signal point and the attenuated signal amplitude is calculated; the confusion degree is the ratio of the difference to the signal amplitude of each pulse signal point.

5. The flow measurement method of a partially full tube electromagnetic flowmeter according to claim 1, characterized in that: The expression of the local disorder aggregation degree is: Where, represents the local disorder concentration degree of the qth pulse signal point; U represents the number of preset neighboring pulse signal points of the qth pulse signal point; 、 They respectively represent the confusion degree of the preset u-th and u+1-th neighboring pulse signal points of the q-th pulse signal point; ε represents a preset positive number; Indicates the absolute value operation.

6. The flow measurement method of a partially full tube electromagnetic flowmeter according to claim 1, characterized in that: The process of obtaining the association degree is as follows: Calculating the deviation value of the initial liquid level height between each pulse signal point and each adjacent pulse signal point, and counting the maximum value of the deviation values ​​between each pulse signal point and all adjacent pulse signal points; Calculating a ratio of a normalized value of the Reynolds number to a normalized value of the maximum value, and calculating a difference between the ratio and 1; The correlation degree is the reciprocal of the sum of the difference value and a preset positive number.

7. The flow measurement method of a partially full tube electromagnetic flowmeter according to claim 1, characterized in that: The process of optimizing the disorder degree is as follows: Obtaining a disorder degree optimization factor for each pulse signal point through the correlation degree and the local disorder concentration degree; The sum of the chaos degree optimization factor and 1 is calculated, and the product of the sum and the chaos degree of each pulse signal point is used as the optimized chaos degree of each pulse signal point.

8. The flow measurement method of a partially full tube electromagnetic flowmeter according to claim 7, characterized in that: The disorder optimization factor is a normalized value of the product of the correlation degree and the local disorder aggregation degree.

9. The flow measurement method of a partially full tube electromagnetic flowmeter according to claim 1, characterized in that: The process of screening mismatched pulse signal points from all pulse signal points is as follows: According to the optimized confusion degree of all pulse signal points, all pulse signal points are divided into two categories, the average of the optimized confusion degree of all pulse signal points in each category is calculated, and each pulse signal point in the category with the largest average value is used as a mismatched pulse signal point.

10. The flow measurement method of a partially full tube electromagnetic flowmeter according to claim 1, characterized in that: In the process of reacquiring each matching echo signal point of each mismatched pulse signal point, the fitness value of each particle in the particle swarm algorithm is the reciprocal of the sum of the optimized disorder degrees of all pulse signal points under each particle.

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