Ultrasonic flow fusion method and system based on multiple modes

Abstract

The invention belongs to the technical field of flow detection, and particularly relates to an ultrasonic flow fusion method and system based on multiple modalities, and the method comprises the following steps: S100, constructing a modal number selection model in advance; s200, a first probe and a second probe are adopted to send a first transmitting signal and a second transmitting signal respectively, and a first receiving signal and a second receiving signal are collected correspondingly; s201, a corresponding mode selection number is matched in the mode number selection model; s202, at least three modes are selected from the modes according to the mode selection number, and the selected at least three modes are divided into at least two mode groups; s203, the volume flow is obtained through calculation according to the modal group; and S205, a flow mean value is calculated according to the at least two volume flows, and compared with flow measurement in a single mode, the flow measurement precision in a large-pipe-diameter scene is greatly improved.

Description

[0001] Priority application This application claims priority to Chinese invention patent application filed on December 19, 2024, [2024118795026], entitled "[A Multimodal Ultrasonic Flow Fusion Method and System]", which is incorporated herein by reference in its entirety. Technical Field

[0002] This invention belongs to the field of flow detection technology, specifically relating to a multimodal ultrasonic flow fusion method and system. Background Art

[0003] In the field of ultrasonic flow meter measurement, the flow meters used in natural gas metering applications in my country still mainly rely on imports. Foreign ultrasonic flow meters have a longer history of development, and several brands are widely used in on-site metering in the natural gas field, offering high accuracy and comprehensive functionality. However, foreign brands of ultrasonic flow meters are very expensive. Domestic research on ultrasonic flow meters started relatively late. Due to the advantages of ultrasonic flow meters in natural gas metering and market demand, domestic research on ultrasonic flow meters is currently developing rapidly, with an increasing number of researchers, promoting the localization of ultrasonic flow meter production.

[0004] As ultrasonic flow meters have undergone continuous iterations, it has been discovered that the speed of sound (ultrasound velocity) in a medium varies with temperature, thus significantly affecting the accuracy of flow measurement results. To address this, Chinese invention patent CN101464171B discloses an ultrasonic flow detection system and method, specifically a high-precision ultrasonic system and method for detecting fluid flow. This method employs an improved time-of-flight method to calculate fluid velocity; utilizes delayed window reception technology; and reduces the impact of noise on detection accuracy through pulse width detection. Furthermore, it employs interpolation correlation and correlation coefficient judgment methods to further improve the system's measurement time resolution to 1.25 ns, thereby significantly improving the accuracy and precision of the ultrasonic flow meter and effectively avoiding the adverse effects of temperature on flow measurement results.

[0005] However, while the aforementioned devices have some applicability, their application scenarios are quite limited.

[0006] Therefore, there is an urgent need for a method to improve the accuracy of flow measurement. Summary of the Invention

[0007] The purpose of this invention is to provide a multimodal ultrasonic flow fusion method and system to improve the measurement accuracy of flow in large-diameter pipe scenarios.

[0008] To solve the aforementioned technical problems, the present invention specifically adopts the following technical solution: A first aspect of the present invention is to provide a multimodal ultrasonic flow fusion method, comprising the following steps: S200, using a first probe and a second probe respectively to send a first transmission signal and a second transmission signal, and correspondingly acquire a first reception signal and a second reception signal; wherein, the first transmission signal or the second transmission signal generates at least three modes during propagation in the system to be measured, and the first reception signal or the second reception signal includes the reception signal under the at least three modes; S201, Select at least three modes from the modes generated in S200; S202, the at least three modes selected in S201 are divided into at least two mode groups, wherein one mode group includes two modes; S203, define the two modes in the mode group as the first mode and the second mode respectively; obtain the first downstream propagation time and the first upstream propagation time under the first mode, and the second downstream propagation time and the second upstream propagation time under the second mode respectively through the received signal, and calculate the volumetric flow rate under the mode group using the following model; in, ; ; In the formula, For volumetric flow rate, For the first downstream propagation time, For the first reverse propagation time, For the second downstream propagation time, This is the second retrograde propagation time. As the first coefficient, As the second coefficient, The third coefficient, For fluid flow velocity, The distance between the first probe and the second probe. Let be the radius of the pipe in the system to be measured; S205, calculate the average flow rate based on at least two of the volumetric flow rates.

[0009] As an improvement, prior to S205, the following steps are also included: S204, the volumetric flow rate is corrected by multiplying the volumetric flow rate by a pre-obtained calibration coefficient.

[0010] As an improvement, in S204, the method for obtaining the calibration coefficients includes: S41, Conduct a preliminary experiment under experimental conditions to obtain the actual flow results of the current mode group within the calibration area under the experimental conditions. and calculation of flow results The calibration region is the region corresponding to at least two modes among the multiple modes obtained through the pre-experiment. S42, based on the actual flow results and the calculated flow results The calibration coefficients were calculated. ; .

[0011] As an improvement, the process of obtaining the calibration coefficients further includes the following steps: S43, Under different experimental conditions, repeat the pre-experiment to obtain calibration coefficients under different experimental conditions, wherein the experimental conditions include at least the number of modes; Accordingly, in S204, before correcting the volumetric flow rate, the following steps are also included: Obtain the current conditions and match the experimental conditions according to the current conditions to obtain the calibration coefficients matched under the current conditions.

[0012] As an improvement, S204 further includes the step of: before correcting the volumetric flow rate. S206, Obtain the current conditions and match the current conditions with the experimental conditions. The specific steps include: S61, acquire at least three sets of received signals in at least three modes within the calibration area under the current conditions, and at least three sets of standard received signals measured in at least three modes within the calibration area under experimental conditions; S62, calculate the amplitude difference between the received signal and the standard received signal respectively to obtain at least three amplitude differences; S63, determine whether the at least three amplitude differences are all less than the first preset difference; if so, match the current condition with the experimental condition. S207, Obtain the calibration coefficients under the experimental conditions.

[0013] As an improvement, in S201, the specific steps of selecting at least three modes include: determining whether the current mode meets the selection conditions, wherein the selection conditions require that the amplitude of the received signal in the current mode is greater than a first preset amplitude threshold, and / or the signal length of the received signal in the current mode conforms to a first preset length threshold range; if so, the mode is selected, otherwise the mode is not selected.

[0014] Another aspect of this invention is to provide a multimodal ultrasonic flow fusion system, comprising: The second acquisition module is configured to transmit a first transmission signal and a second transmission signal using a first probe and a second probe, respectively, and to acquire a first reception signal and a second reception signal accordingly; wherein, the first transmission signal or the second transmission signal generates at least three modes during propagation in the system to be measured, and the first reception signal or the second reception signal includes the reception signal under the at least three modes; The second modality selection module is configured to select at least three modalities from the modalities acquired by the second acquisition module. Modality grouping module: configured to divide at least three modes selected by the second modality selection module into at least two modality groups, wherein one modality group includes two modes; The data acquisition module is configured to define two modes in the mode group as a first mode and a second mode, respectively; and to acquire the first downstream propagation time and the first upstream propagation time under the first mode, and the second downstream propagation time and the second upstream propagation time under the second mode, respectively, through the received signal. The second calculation module is configured to calculate the volumetric flow rate under the said mode group using the following model; and to calculate the average flow rate based on at least two said volumetric flow rates. in, ; ; In the formula, For volumetric flow rate, For the first downstream propagation time, For the first reverse propagation time, For the second downstream propagation time, This is the second retrograde propagation time. As the first coefficient, As the second coefficient, The third coefficient, For fluid flow velocity, The distance between the first probe and the second probe. Let be the radius of the pipe in the system under test.

[0015] As an improvement, it also includes: The second correction module is configured to correct the volumetric flow rate by multiplying the volumetric flow rate by a pre-obtained calibration coefficient.

[0016] As an improvement, the second correction module is specifically configured to: Preliminary experiments were conducted under experimental conditions to obtain the actual flow results of the current mode group within the calibration area under those conditions. and calculation of flow results The calibration region is the region corresponding to at least two modes among the multiple modes obtained through the pre-experiment. Based on the actual traffic results and the calculated flow results The calibration coefficients were calculated. ;in, .

[0017] As an improvement, when obtaining the calibration coefficient, the second correction module is also configured to repeat the pre-experiment under different experimental conditions to obtain the calibration coefficient under different experimental conditions, wherein the experimental conditions include at least the number of modes; correspondingly, before correcting the volumetric flow rate, the second correction module is also configured to obtain the current conditions and match the experimental conditions according to the current conditions to obtain the calibration coefficient matched under the current conditions.

[0018] The principle and beneficial technical effects of this invention are as follows: In large-diameter pipes, the higher flow velocity results in greater fluid kinetic energy, leading to increased fluctuations in fluid flow. As the flow velocity increases, the disturbance of ultrasonic waves by the fluid also increases, causing a significant error in the measurement of ultrasonic signal propagation time. This error is amplified in subsequent calculations, thus greatly increasing the error in the volumetric flow rate calculated based on time.

[0019] For the aforementioned scenarios of large-diameter, high-flow-velocity pipes, this application compensates for errors by measuring the ultrasonic transmission time difference between finite modes (dual modes) within a finite mode group. This is achieved by measuring the forward and reverse flow time differences between two different modes (including the forward and reverse flow time differences of the first mode, the forward and reverse flow time differences of the second mode, and the cross-forward and reverse flow time differences of the first and second modes, forming a multi-dimensional time difference), and using this multi-dimensional time difference information to compensate for the measurement errors under a single mode. Furthermore, the finite number of volumetric flow rate data obtained after compensation are corrected and fused to obtain the compensated and corrected comprehensive volumetric flow rate, which greatly improves the accuracy of flow measurement in large-diameter pipes.

[0020] First, this application provides a high-intensity, wide-amplitude modal data acquisition mechanism that imposes dual restrictions on amplitude and signal length, selecting the two most representative modes. On the one hand, the mode with a larger amplitude can preserve the integrity of the original signal to the greatest extent and reduce interference from other factors (such as noise). On the other hand, by limiting the signal length and selecting the mode with a larger received signal length within a preset length threshold range, a wider data acquisition window can be divided under this mode, thereby acquiring more data point information. Then, multiple data point information can be used as raw data to calculate a more accurate upstream and downstream flow time, thereby improving the accuracy of flow measurement without excessively increasing the amount of data acquisition and processing signals.

[0021] Furthermore, this application adaptively selects a finite number of modes matching the total number of ultrasonic modes, divides the selected finite number of modes into finite number of mode groups, calculates the flow rate for each group, and finally corrects and integrates the multiple flow rate results, which greatly improves the measurement accuracy of volumetric flow rate.

[0022] In the correction process, corresponding calibration coefficients are determined for different experimental conditions (e.g., different numbers of modes). This allows for matching the specified calibration coefficients under the current mode during the measurement of volumetric flow rate, thereby further improving accuracy. Furthermore, before matching the calibration coefficients, preliminary screening of the current conditions is performed, such as limiting the signal length and amplitude within the calibration area, to select more reliable calibration coefficients. This effectively avoids problems such as inaccurate received signals (modes) caused by unstable excitation signals or other accidental factors. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. The elements or parts in the drawings are not necessarily drawn to scale. Obviously, the drawings described below are some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0024] Figure 1 This is a schematic diagram illustrating the flow meter measurement principle in an embodiment of the present invention; Figure 2 This is a schematic diagram of the signal characteristics of the ultrasonic flow meter in an embodiment of the present invention; Figure 3 This is a flowchart of the temperature-adaptive ultrasonic flow measurement method in an embodiment of the present invention; Figure 4This is a modular schematic diagram of the temperature-adaptive ultrasonic flow measurement system in an embodiment of the present invention; Figure 5 This is a flowchart of a multimodal ultrasonic flow fusion method in an embodiment of the present invention; Figure 6 This is a modular schematic diagram of a multimodal ultrasonic flow fusion system in an embodiment of the present invention; Figure 7 This is a schematic diagram of the amplitude of the acoustic wave fluctuations in the first mode of simulation experiment 1, showing the forward and reverse flow. Figure 8 This is a schematic diagram of the amplitude of the acoustic wave fluctuations in the second mode under simulation experiment 1; Figure 9 This is a comparison chart of the flow rate change rates in simulation experiment 1; Figure 10 This is a schematic diagram of the amplitude of the upstream and downstream acoustic wave fluctuations in the first mode of simulation experiment 2; Figure 11 This is a schematic diagram of the amplitude of the upstream and downstream acoustic wave fluctuations in the second mode of simulation experiment 2. Figure 12 This is a comparison chart of the flow rate change rates in simulation experiment 2. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0026] In this document, suffixes such as "module," "component," or "unit" used to denote elements are used solely for the purpose of illustrative purposes and have no specific meaning in themselves. Therefore, "module," "component," or "unit" may be used interchangeably. In this document, terms such as "upper," "lower," "inner," "outer," "front," "rear," "one end," and "the other end," indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and for 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, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In this document, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," and "connected," etc., should be interpreted broadly. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; it can also refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. In this document, "multiple" means two or more, i.e., it includes two, three, four, five, etc.

[0028] The principle of ultrasonic measurement in existing technology is as follows: Figure 1 As shown, in an ultrasonic probe (mainly consisting of a piezoelectric ceramic plate and an acoustic wedge), the piezoelectric ceramic is connected to the pipe wall via the acoustic wedge, and the sound wave propagation path can be extended by changing the position of the acoustic wedge.

[0029] The angle between the normal direction of the piezoelectric ceramic sheet and the normal direction of the pipe wall is... The pipe wall thickness is The distance between the acoustic wedges is The piezoelectric ceramic sheet is located on the axial plane of the pipe. The pipe radius is measured as... Assuming the pipe wall and ultrasonic wedge are made of the same material, the ultrasonic waves propagate at the same speed in both the wedge and the pipe wall, without any angular change. However, on the inner wall of the pipe, the different propagation speeds of sound waves in different media lead to varying refraction angles. Let the speeds of sound propagation in the pipe wall and the fluid be respectively... and Then the angle of refraction satisfies Snell's law, that is: (1) An electrical signal excites piezoelectric ceramic 1 to generate an ultrasonic mechanical signal. The ultrasonic signal is refracted at the pipe wall and enters the propellant, propagating in the flow direction. Upon reaching piezoelectric ceramic 2, it generates a piezoelectric signal, forming an electrical signal. The propagation time difference between the two signals is denoted as the downstream time. On the other hand, when an electrical signal excites the piezoelectric ceramic 2, the propagation direction of the ultrasonic waves is opposite to the flow direction, forming a counter-current time. .

[0030] In pipe flow, the flow field formed by fluid flow is relatively complex. For ease of modeling, we assume that the fluid flow field is a uniform flow field. If the propagation time of sound waves in the acoustic wedge and the pipe wall is not considered, then Figure 1 The corresponding propagation times for upstream and downstream are: (2) Then there is (3) at the same time (4) Substituting formula (4) into formula (3) yields the following result: (5) The volumetric flow rate can then be expressed as (6) Similarly, substituting formula (5) into formula (4) yields the speed of sound. (7) Furthermore, from formula (1), we can obtain that... Since it is related to the speed of sound wave propagation in the fluid, substituting formula (1) into the above equation yields... (8) In the above formula, This represents the speed of sound propagation in a solid. In a fluid, when the speed of sound is known and the fluid pressure remains relatively constant, there is a correlation between the speed of sound and temperature, allowing us to obtain the fluid temperature and, consequently, the fluid density.

[0031] Furthermore, volumetric flow rate can be expressed as (9) It is not difficult to see that and The pipe radius is determined during the design phase and will not change. The velocity of sound within the pipe wall. Due to the influence of temperature, temperature compensation experiments need to be conducted to compensate for the effects.

[0032] When using continuous waves, assume the frequency of the sound wave signal is... Then time ( ) and phase ( There exists the following formula (10) Substituting the above equation into formula (8), we can obtain the speed of sound in the fluid as follows: (11) in, It is the counter-current phase. It is the downstream phase; Substituting the above formula into formula (9) yields the volumetric flow rate formula. (12) As can be seen from the formula, both time-based volume measurement (Formula (9)) and phase-based volume measurement (Formula (12)) involve the propagation speed of sound waves. This parameter is given as a parameter. This parameter changes with different temperatures.

[0033] Example 1 To eliminate the influence of temperature on volumetric flow rate measurement, this invention provides a temperature-adaptive ultrasonic flow rate measurement method, see [link to relevant documentation]. Figure 3 This includes the following steps: S101, a first transmission signal and a second transmission signal are transmitted using a first probe and a second probe, respectively, and a first reception signal and a second reception signal are acquired accordingly; wherein, the first transmission signal or the second transmission signal generates multiple modes during propagation in the system to be measured, and the first reception signal or the second reception signal includes the reception signal under the multiple modes; S102, select two modes from the plurality of modes, and define the two selected modes as the first mode and the second mode, respectively; S103, the first downstream propagation time and the first upstream propagation time under the first mode, and the second downstream propagation time and the second upstream propagation time under the second mode are obtained respectively through the received signal; S104, based on the first downstream propagation time, the first upstream propagation time, the second downstream propagation time, and the second upstream propagation time, the volumetric flow rate is calculated using the following model: ; ; In the formula, For volumetric flow rate, For the first downstream propagation time, For the first reverse propagation time, For the second downstream propagation time, This is the second retrograde propagation time. As the first coefficient, As the second coefficient, The third coefficient, For fluid flow velocity, The distance between the first probe and the second probe. Let be the pipe radius of the system to be measured.

[0034] Among them, when When this time, it indicates that the fluid in the pipe is flowing in the forward direction. when When this occurs, it indicates that the fluid in the pipe is flowing in the reverse direction. The device used to obtain modal information in S101 can be referred to the inventor's prior patent (CN115493662B, Integrated Ultrasonic Flow Meter and System for Aerospace); the acquisition of relevant parameters of multiple modes can be referred to the patent (CN119023015A, Multimodal Ultrasonic Fluid Multi-parameter Measurement Device and Method).

[0035] In some embodiments, the specific steps for selecting the mode in S102 include: S1021, determine whether the current mode meets the selection conditions. The selection conditions require that the amplitude of the received signal in the current mode is greater than a first preset amplitude threshold, and / or that the signal length of the received signal in the current mode conforms to a first preset length threshold range. If so, the mode is included in the selectable mode set. That is, determine whether the amplitude of the received signal in the current mode is greater than the first preset amplitude threshold, and / or determine whether the signal length of the received signal in the current mode conforms to a first preset length threshold range. If at least one of the above conditions is met (including the following three cases: 1. The amplitude of the received signal in the current mode is greater than the first preset amplitude threshold, but the signal length of the received signal in the current mode does not conform to the first preset length threshold range; 2. The amplitude of the received signal in the current mode is less than the first preset amplitude threshold, but the signal length of the received signal in the current mode conforms to the first preset length threshold range; 3. The amplitude of the received signal in the current mode is greater than the first preset amplitude threshold, and the signal length of the received signal in the current mode conforms to the first preset length threshold range), then the mode is included in the selectable mode set.

[0036] S1023, Select two modes from the set of optional modes, and define the two modes as the first mode and the second mode, respectively.

[0037] This application provides a high-intensity, wide-amplitude modal data acquisition mechanism to directly improve the accuracy of flow measurement from the data source.

[0038] Among them, see Figure 2 Amplitude refers to the intensity of the received signal corresponding to each mode. The greater the intensity of the received signal, the greater its amplitude. Signal length refers to the width of the received signal corresponding to each mode. For example, the signal length corresponding to mode 3 is X. In this application, the number of excitation signal cycles is limited to about 60, and the number of sampling points within the corresponding signal length range is 1024. By limiting the number of excitation signal cycles, the amount of data collected is guaranteed without excessively increasing the difficulty of data processing. This avoids the problem that an excessively large excitation signal would lead to an excessively long acquisition signal, which in turn would increase the amount of data acquisition and processing.

[0039] The signal length refers to the actual time span of the signal from start to finish, usually expressed in seconds (s); the number of sampling points represents the number of times the signal is sampled at discrete time points.

[0040] This application improves the accuracy of flow measurement directly from the data source by limiting both the amplitude and signal length of the mode and selecting key modes for calculation. Specifically, modes with larger amplitudes are generally less affected by interference during transmission and are more accurate. Furthermore, when the received signal length is large, a wider data acquisition window can be defined within that mode, thereby acquiring more data points (i.e., sampling data selected from the received signal, which may include the acquisition time and / or amplitude). These multiple data points are then used as raw data to calculate more accurate upstream and downstream flow times using Fourier transform. The specific steps for calculating upstream and downstream flow times using Fourier transform can be found in Chinese Invention Patent CN119023014A, which details the steps for calculating the upstream delay time (equivalent to the upstream propagation time in this document) and the downstream delay time (equivalent to the downstream propagation time in this document).

[0041] In some embodiments, S1021 further includes determining whether the duration of the current excitation signal is greater than a first preset time threshold. When the duration of the excitation signal is long, a sufficient number of modes can usually be generated. Selecting key modes from these modes for data acquisition is more representative and the measured data is more accurate.

[0042] In some embodiments, S1021 further includes determining whether the amplitude of the received signal in the current mode is less than a second preset amplitude threshold; if so, the mode is assigned to the optional mode set.

[0043] See also Figure 2Different modes correspond to different amplitudes and durations. In this paper, the first preset amplitude threshold can be a specific amplitude determined by the user based on the amplitudes of multiple modes under different experimental conditions obtained from pre-experiments, but this amplitude should be lower than the safe amplitude value (if the sound wave amplitude is too large, it may damage the equipment; therefore, the safe amplitude value refers to the maximum amplitude value that will not cause damage to the equipment). Correspondingly, the second preset amplitude threshold can be an amplitude value between the first preset amplitude threshold and the safe amplitude value. Correspondingly, the first preset length threshold range can be a specific signal length threshold range determined by the user based on the signal lengths of multiple modes under different experimental conditions obtained from pre-experiments. Signal lengths within this range can ensure that the received signals of the modes can be collected as much as possible, but without collecting too many invalid signals. The first preset time threshold can be a specific time value determined by the user based on the durations of multiple modes under different experimental conditions obtained from pre-experiments.

[0044] In some embodiments, before S1023, the method further includes the step of: S1022, determining whether the number of modes in the optional mode set is greater than or equal to two; if so, then S1023 is executed; otherwise, the first preset amplitude threshold is adjusted according to the first reduction until the number of modes is greater than or equal to two.

[0045] In other words, the first preset amplitude threshold can also be adjusted according to the actual situation to ensure that the number of modes in the selectable mode set is greater than or equal to two.

[0046] In some embodiments, step S1023, the specific steps of selecting two modes from the optional mode set, include: when the number of modes is greater than two, selecting the mode with the largest amplitude of the received signal as the first mode, and selecting the mode with the amplitude of the received signal that is closest to the first amplitude of the first mode as the second mode.

[0047] In some embodiments, the steps further include: S105, the volumetric flow rate obtained in S104 is corrected using a preset correction rule, which is to multiply the volumetric flow rate by a pre-obtained calibration coefficient.

[0048] In some embodiments, the calibration coefficients are obtained in the following manner: Preliminary experiments were conducted under experimental conditions to obtain the actual flow rate results of the current pipeline (measurement system) modally within the calibration area under experimental conditions. and calculation of flow results The calibration region is the region corresponding to at least two modes among the multiple modes obtained through the pre-experiment. Based on the actual traffic results and the calculated flow results The calibration coefficients were calculated. ; ; Among them, the calculated flow results The actual flow rate result is obtained by calculating using the above steps S101-S104. The volumetric flow rate of the fluid injected into the pipeline can be directly obtained by pre-setting the flow rate.

[0049] In some embodiments, when determining the calibration coefficients, the method further includes the step of: repeating the pre-experiment under different experimental conditions to obtain the calibration coefficients under different experimental conditions, wherein the experimental conditions include at least the number of modes; Accordingly, in S105, before correcting the volumetric flow rate, the method further includes: obtaining the current conditions and matching the experimental conditions according to the current conditions to obtain the calibration coefficient matched under the current conditions.

[0050] In some embodiments, the specific steps for matching the experimental conditions according to the current conditions include: S51, acquire at least two sets of received signals (also known as amplitude signals) of at least two modes in the calibration area under the current conditions, and at least two sets of standard received signals measured under at least two modes in the calibration area under experimental conditions; S52, calculate the amplitude difference between the at least two sets of received signals and the at least two sets of standard received signals respectively, and obtain at least two amplitude difference values; S53, determine whether at least two amplitude differences are both less than a first preset difference; if so, match the current condition with the experimental condition.

[0051] In some embodiments, the specific steps for matching the experimental conditions according to the current conditions include: S54, acquire the received signals of at least two modes within the calibration area under the current conditions; S55, determine whether the signal lengths in the received signals all conform to the first preset length threshold range; if so, match the current conditions with the experimental conditions.

[0052] It should be noted that when matching the experimental conditions according to the current conditions, only one of the indicators, amplitude or signal length, can be selected for matching, or both amplitude and signal length can be selected for matching. Furthermore, if a mismatch occurs, the amplitude and / or signal length can be remeasured for matching, or the excitation conditions can be adjusted or other methods can be used to re-obtain the amplitude and / or signal length for matching.

[0053] To verify the reliability of this scheme, the following verification experiments were conducted, among which, verification experiment 1 (see Figures 7-9 The results were obtained from a verification experiment conducted at an ambient temperature of -14℃ and an internal medium temperature of -16℃. Figure 7 and Figure 8 This is a schematic diagram showing the time-varying amplitude of the upstream and downstream acoustic waves in the first mode (mode 1) and the second mode (mode 2). Based on... Figure 7 and Figure 8 The data in the diagram illustrates the flow rate variation of the ultrasonic flow meter, and the flow rate variation data directly measured by a standard mass flow meter is introduced to obtain... Figure 9 The flow rate change comparison chart shown indicates that the flow rate measured using this method is basically consistent with the standard data measured by the mass flow meter under ideal conditions, which also confirms the reliability of this method.

[0054] To further verify the accuracy of this scheme, the above experiment was conducted again at an ambient temperature of -13℃ and an internal medium temperature of -15.8℃ (verification experiment 2), see details below. Figures 10-12 It can be seen that under these conditions, the flow rate measured by this method is very close to the standard data measured by the standard mass flow meter, which further confirms the reliability of this method.

[0055] Therefore, the above method of representing volumetric flow rate does not take into account the propagation speed of sound waves, thus achieving temperature adaptability.

[0056] In summary, this invention compensates for the error based on the ultrasonic transmission time difference between finite modes (dual modes), and provides a more accurate temperature-adaptive flow measurement method, which is especially suitable for measuring flow rates in large-diameter pipes.

[0057] Furthermore, this application provides a high-intensity, wide-amplitude modal data acquisition mechanism that imposes dual restrictions on amplitude and signal length, selecting the two most representative modes. On the one hand, the mode with a larger amplitude can preserve the integrity of the original signal to the greatest extent and reduce interference from other factors (such as noise). On the other hand, by restricting the signal length and selecting the mode with a larger received signal length within a preset length threshold range, a wider data acquisition window can be divided under this mode, thereby acquiring more data point information. Then, multiple data point information can be used as raw data to calculate a more accurate forward and reverse flow time, thereby improving the accuracy of flow measurement without excessively increasing the amount of data acquisition and processing.

[0058] Furthermore, this invention corrects the measured flow rate results, which can further compensate for errors caused by differences in conditions (e.g., ultrasonic signals with different periods excite different numbers of modes), thereby further improving the accuracy of flow rate measurement. Specifically, during the correction process, corresponding calibration coefficients are determined for different experimental conditions (e.g., different numbers of modes), enabling the matching of specified calibration coefficients under the current mode during volumetric flow rate measurement, further improving accuracy. In addition, before matching the calibration coefficients, preliminary screening of the current conditions is performed, for example, limiting the length and amplitude of the acquired signal within the calibration area, to select more reliable calibration coefficients, effectively avoiding inaccurate received signals (modes) caused by factors such as unstable excitation signals or other accidental factors.

[0059] Example 2 See also Figure 4 This invention provides a temperature-adaptive ultrasonic flow measurement system, comprising: The first acquisition module is configured to transmit a first transmission signal and a second transmission signal using a first probe and a second probe, respectively, and to acquire a first received signal and a second received signal accordingly; wherein, the first transmission signal or the second transmission signal generates multiple modes during propagation in the system to be measured, and the first received signal or the second received signal includes received signals under the multiple modes; The first mode selection module is configured to select two modes from the plurality of modes, and the two modes are defined as the first mode and the second mode, respectively. Time acquisition module: configured to acquire, respectively, the first downstream propagation time and the first upstream propagation time in the first mode, and the second downstream propagation time and the second upstream propagation time in the second mode through the received signal; The first calculation module is configured to calculate the volumetric flow rate based on the first downstream propagation time, the first upstream propagation time, the second downstream propagation time, and the second upstream propagation time, using the following model: ; ; In the formula, For volumetric flow rate, For the first downstream propagation time, For the first reverse propagation time, For the second downstream propagation time, This is the second retrograde propagation time. As the first coefficient, As the second coefficient, The third coefficient, For fluid flow velocity, The distance between the first probe and the second probe. Let be the pipe radius of the system to be measured.

[0060] Among them, when When this time, it indicates that the fluid in the pipe is flowing in the forward direction. when When this occurs, it indicates that the fluid in the pipe is flowing in the reverse direction. In some embodiments, the first mode selection module is specifically configured to determine whether the current mode meets the selection conditions, wherein the selection conditions require that the amplitude of the received signal in the current mode is greater than a first preset amplitude threshold, and / or the signal length of the received signal in the current mode conforms to a first preset length threshold range; if so, the mode is included in the selectable mode set; and two modes are selected from the selectable mode set, and the two modes are defined as the first mode and the second mode, respectively.

[0061] In some embodiments, it also includes: Modality count determination module: configured to determine whether the number of modes in the optional mode set is greater than or equal to two; Adjustment module: configured to adjust the first preset amplitude threshold by a first reduction when the number of modes in the selectable mode set is less than two, until the number of modes is greater than or equal to two.

[0062] In some embodiments, the first mode selection module is specifically configured to: when the number of modes is greater than two, select the mode with the largest amplitude of the received signal as the first mode, and select the mode with the amplitude of the received signal that is closest to the first amplitude of the first mode as the second mode.

[0063] In some embodiments, the system further includes: a first correction module configured to correct the volumetric flow rate calculated by the first calculation module using a preset correction rule, wherein the correction rule is to multiply the volumetric flow rate by a pre-obtained calibration coefficient.

[0064] The calibration coefficients are obtained in the following manner: A preliminary experiment was conducted under experimental conditions to obtain the actual flow rate of the current pipeline under those conditions. and calculation of flow results ; Based on the actual traffic results and the calculated flow results The calibration coefficients were calculated. ; ; Among them, the calculated flow results The actual flow rate result is obtained by calculating using the first calculation module described above. The volumetric flow rate of the fluid injected into the pipeline can be directly obtained by pre-setting the flow rate.

[0065] In some embodiments, when determining the calibration coefficients, the method further includes the step of: repeating the pre-experiment under different experimental conditions to obtain the calibration coefficients under different experimental conditions, wherein the experimental conditions include at least the number of modes; Accordingly, before correcting the volumetric flow rate, the method further includes: Obtain the current conditions and match the experimental conditions according to the current conditions to obtain the calibration coefficients matched under the current conditions.

[0066] Example 3 See also Figure 5 This invention provides a multimodal ultrasonic flow fusion method, comprising the following steps: S200, using a first probe and a second probe respectively to send a first transmission signal and a second transmission signal, and correspondingly acquire a first reception signal and a second reception signal; wherein, the first transmission signal or the second transmission signal generates at least three modes during propagation in the system to be measured, and the first reception signal or the second reception signal includes the reception signal under the at least three modes; Specifically, when one probe sends a sinusoidal pulse beam (a beam composed of multiple cycles), i.e., transmits a signal, the corresponding other probe receives six ultrasonic modes with different propagation speeds (such as...). Figure 2 The modes are 1, 2, ..., 6, meaning each mode corresponds to a receiving signal at one end.

[0067] S201, Select at least three modes from the modes generated in S200; S202, the at least three modes selected in S201 are divided into at least two mode groups, wherein one mode group includes two modes; S203, define the two modes in the mode group as the first mode and the second mode respectively; obtain the first downstream propagation time and the first upstream propagation time under the first mode, and the second downstream propagation time and the second upstream propagation time under the second mode respectively through the received signal, and calculate the volumetric flow rate under the mode group using the following model; in, ; ; In the formula, For volumetric flow rate, For the first downstream propagation time, For the first reverse propagation time, For the second downstream propagation time, This is the second retrograde propagation time. As the first coefficient, As the second coefficient, The third coefficient, For fluid flow velocity, The distance between the first probe and the second probe. Let be the radius of the pipe in the system to be measured; S205, calculate the average flow rate based on at least two of the volumetric flow rates.

[0068] In some embodiments, prior to S200, the following steps are also included: S100, Pre-construct a modality number selection model, wherein the step of pre-constructing the modality number selection model includes setting at least two modality number ranges and matching corresponding modality selection numbers for the at least two modality number ranges respectively; Accordingly, in S200, a first transmission signal and a second transmission signal are transmitted using a first probe and a second probe, respectively, and a first reception signal and a second reception signal are acquired accordingly; wherein, the first transmission signal or the second transmission signal generates at least three modes during propagation in the system to be measured, and the first reception signal or the second reception signal includes the reception signal under the at least three modes; S201, based on the number of modes generated in S200, match a corresponding number of modes in the mode selection model, wherein the number of modes selected is greater than or equal to three, and select at least three modes in the mode based on the number of modes selected; S202, the selected at least three modes are divided into at least two mode groups, wherein one mode group includes two modes; When dividing the modes into at least two mode groups, the number can be determined based on the total number of modes and the selected number of modes. For example, see [link to relevant documentation]. Figure 2 The figure shows the case where there are a total of 6 modes. In this case, the total number of modes is relatively small, so three or four modes can be selected and divided into two mode groups. For example, when the total number of modes is large (not shown in the figure), more modes can be selected (preferably an even number of modes) and they can be combined into three or more mode groups.

[0069] S203, define the two modes in the mode group as the first mode and the second mode respectively; obtain the first downstream propagation time and the first upstream propagation time under the first mode, and the second downstream propagation time and the second upstream propagation time under the second mode respectively through the received signal, and calculate the volumetric flow rate under the mode group using the following formula; in, ; ; In the formula, For volumetric flow rate, For the first downstream propagation time, For the first reverse propagation time, For the second downstream propagation time, This is the second retrograde propagation time. As the first coefficient, As the second coefficient, The third coefficient, For fluid flow velocity, The distance between the first probe and the second probe. The radius of the pipe to be measured; Among them, when When this time, it indicates that the fluid in the pipe is flowing in the forward direction. when When this occurs, it indicates that the fluid in the pipe is flowing in the reverse direction. For different mode groups, execute S203 respectively to obtain the corresponding volumetric flow rates under multiple mode groups.

[0070] It should be noted that the first coefficient in this article Second coefficient and the third coefficient The name is merely for differentiation and can be understood as a representative character. It is obtained by different calculation methods based on the first downstream propagation time, the first upstream propagation time, the second downstream propagation time, and the second upstream propagation time, and has no actual meaning.

[0071] S205, the average flow rate is calculated based on the volumetric flow rate(s)(s).

[0072] In some embodiments, prior to S205, the following step is also included: S204, the volumetric flow rate is corrected by multiplying the volumetric flow rate by a pre-obtained calibration coefficient.

[0073] In some embodiments, the method for obtaining the calibration coefficients includes: S41, Conduct a preliminary experiment under experimental conditions to obtain the actual flow results of the current mode group within the calibration area under the experimental conditions. and calculation of flow results The calibration region is the region corresponding to at least two modes among the multiple modes obtained through the pre-experiment. S42, based on the actual flow results and the calculated flow results The calibration coefficients were calculated. ; ; Among them, the calculated flow results The actual flow rate result is obtained by calculating using the above steps S100-S203. The volumetric flow rate of the fluid injected into the pipeline can be directly obtained by pre-setting the flow rate.

[0074] It should be noted that the calibration coefficient can be one or more. For example, when there is one mode group, there is only one calibration coefficient; when there are two mode groups, there are two calibration coefficients, corresponding to the two mode groups respectively, and so on. In the actual measurement process, the selected mode in the mode group is matched with the mode group corresponding to the calibration coefficient to obtain the calibration coefficient in the current mode group.

[0075] In some embodiments, obtaining the calibration coefficients further includes the step of: S43, Under different experimental conditions, repeat the pre-experiment to obtain calibration coefficients under different experimental conditions, wherein the experimental conditions include at least the number of modes; Accordingly, in S204, before correcting the volumetric flow rate, the method further includes: obtaining the current conditions and matching the experimental conditions according to the current conditions to obtain the calibration coefficient matched under the current conditions.

[0076] In some embodiments, S204 further includes the step of: before correcting the volumetric flow rate. S206, Obtain the current conditions and match the current conditions with the experimental conditions. The specific steps include: S61, acquire at least three sets of received signals in at least three modes within the calibration area under the current conditions, and at least three sets of standard received signals measured in at least three modes within the calibration area under experimental conditions; S62, calculate the amplitude difference between the received signal and the standard received signal respectively to obtain at least three amplitude differences; S63, determine whether the at least three amplitude differences are all less than the first preset difference; if so, match the current condition with the experimental condition. S207, Obtain the calibration coefficients under the experimental conditions.

[0077] In some embodiments, S206 includes the following specific steps for matching the experimental conditions according to the current conditions: S64, acquire at least three sets of received signals in at least three modes within the calibration area under the current conditions; S65, determine whether the signal lengths in the received signals all conform to the first preset length threshold range; if so, match the current condition with the experimental condition signal.

[0078] It should be noted that when matching the experimental conditions according to the current conditions, only one of the indicators, amplitude or signal length, can be selected for matching, or both amplitude and signal length can be selected for matching. Furthermore, if a mismatch occurs, the amplitude and / or signal length can be remeasured for matching, or the excitation conditions can be adjusted or other methods can be used to re-obtain the amplitude and / or signal length for matching.

[0079] In some embodiments, step S201, selecting at least three modes, specifically includes: determining whether the current mode meets the selection criteria, wherein the selection criteria require that the amplitude of the received signal in the current mode is greater than a first preset amplitude threshold, and / or the signal length of the received signal in the current mode conforms to a first preset length threshold range; if so, the mode is included in the selectable mode set. That is, determining whether the amplitude of the received signal in the current mode is greater than the first preset amplitude threshold, and / or determining whether the signal length of the received signal in the current mode conforms to a first preset length threshold range; if at least one of the above conditions is met (including the following three cases: 1. The amplitude of the received signal in the current mode is greater than the first preset amplitude threshold, but the signal length of the received signal in the current mode does not conform to the first preset length threshold range; 2. The amplitude of the received signal in the current mode is less than the first preset amplitude threshold, but the signal length of the received signal in the current mode conforms to the first preset length threshold range; 3. The amplitude of the received signal in the current mode is greater than the first preset amplitude threshold, and the signal length of the received signal in the current mode conforms to the first preset length threshold range), then the mode is included in the selectable mode set.

[0080] In some embodiments, the specific step of selecting at least three modes from the modes according to the mode selection quantity further includes: determining whether the amplitude of the received signal in the current mode is less than a second preset amplitude threshold; if so, selecting the mode; otherwise, not selecting the mode.

[0081] See also Figure 2Different modes correspond to different amplitudes and durations. In this paper, the first preset amplitude threshold can be a specific amplitude determined by the user based on the amplitudes of multiple modes under different experimental conditions obtained from pre-experiments, but this amplitude should be lower than the safe amplitude value (if the sound wave amplitude is too large, it may damage the equipment; therefore, the safe amplitude value refers to the maximum amplitude value that will not cause damage to the equipment; correspondingly, the second preset amplitude threshold can be an amplitude value between the first preset amplitude threshold and the safe amplitude value); correspondingly, the first preset length threshold range can be a specific signal length threshold range determined by the user based on the signal lengths of multiple modes under different experimental conditions obtained from pre-experiments; the first preset time threshold can be a specific time value determined by the user based on the durations of multiple modes under different experimental conditions obtained from pre-experiments.

[0082] In summary, for the aforementioned scenarios of large-diameter, high-flow-rate pipes, this application compensates for errors by measuring the ultrasonic transmission time difference between finite modes (dual modes) within a finite mode group. This is achieved by measuring the forward and reverse flow time differences between two different modes (including the forward and reverse flow time differences of the first mode, the forward and reverse flow time differences of the second mode, and the cross-forward and reverse flow time differences between the first and second modes, a multi-dimensional time difference), and using this multi-dimensional time difference information to compensate for the measurement errors under a single mode. Furthermore, the compensated finite volumetric flow rate data are corrected and fused to obtain the compensated and corrected comprehensive volumetric flow rate, significantly improving the accuracy of flow measurement in large-diameter pipes.

[0083] First, this application provides a high-intensity, wide-amplitude modal data acquisition mechanism that imposes dual restrictions on amplitude and signal length, selecting the two most representative modes. On the one hand, the mode with a larger amplitude can preserve the integrity of the original signal to the greatest extent and reduce interference from other factors (such as noise). On the other hand, by limiting the signal length and selecting the mode with a larger received signal length within a preset length threshold range, a wider data acquisition window can be divided under this mode, thereby acquiring more data point information. Then, multiple data point information can be used as raw data to calculate a more accurate upstream and downstream flow time, thereby improving the accuracy of flow measurement without excessively increasing the amount of data acquisition and processing signals.

[0084] Furthermore, this application adaptively selects a finite number of modes matching the total number of ultrasonic modes, divides the selected finite number of modes into finite number of mode groups, calculates the flow rate for each group, and finally corrects and integrates the multiple flow rate results, which greatly improves the measurement accuracy of volumetric flow rate.

[0085] During the correction process, corresponding calibration coefficients are determined for different experimental conditions (e.g., different numbers of modes). This allows for matching the specified calibration coefficients for the current mode during the measurement of volumetric flow rate, thereby further improving accuracy. Furthermore, before matching the calibration coefficients, preliminary screening of the current conditions is performed, such as limiting the signal length and amplitude within the calibration area, to select more reliable calibration coefficients. This effectively avoids problems such as inaccurate received signals (modes) caused by unstable excitation signals or other accidental factors.

[0086] Example 4 See also Figure 6 This invention provides a multimodal ultrasonic flow fusion system, comprising: The second acquisition module is configured to transmit a first transmission signal and a second transmission signal using a first probe and a second probe, respectively, and to acquire a first reception signal and a second reception signal accordingly; wherein, the first transmission signal or the second transmission signal generates at least three modes during propagation in the system to be measured, and the first reception signal or the second reception signal includes the reception signal under the at least three modes; The second modality selection module is configured to select at least three modalities from the modalities acquired by the second acquisition module. Modality grouping module: configured to divide at least three modes selected by the second modality selection module into at least two modality groups, wherein one modality group includes two modes; The data acquisition module is configured to define two modes in the mode group as a first mode and a second mode, respectively; and to acquire the first downstream propagation time and the first upstream propagation time under the first mode, and the second downstream propagation time and the second upstream propagation time under the second mode, respectively, through the received signal. The second calculation module is configured to calculate the volumetric flow rate under the mode group using the following model; and to calculate the average flow rate based on the volumetric flow rate. in, ; ; In the formula, For volumetric flow rate, For the first downstream propagation time, For the first reverse propagation time, For the second downstream propagation time, This is the second retrograde propagation time. As the first coefficient, As the second coefficient, The third coefficient, For fluid flow velocity, The distance between the first probe and the second probe. Let be the radius of the pipe in the system under test.

[0087] In some specific embodiments, the multimodal ultrasonic flow fusion system includes: Model building module: configured to pre-build a modality number selection model, wherein the steps of pre-building the modality number selection model include setting at least two modality number ranges and matching the corresponding modality selection number for each of the at least two modality number ranges; The second acquisition module is configured to transmit a first transmitted signal and a second transmitted signal using a first probe and a second probe, respectively, and to acquire a first received signal and a second received signal accordingly; wherein the first transmitted signal or the second transmitted signal generates at least three modes during propagation in the system to be measured; Modality number matching module: configured to match a corresponding modality selection number in the modality number selection model based on the number of modalities acquired in the second acquisition module, wherein the modality selection number is greater than or equal to three; Modality grouping module: configured to select at least three modes from the modes according to the modality selection number, and divide the selected modes into at least two modality groups, wherein one modality group includes two modes; The data acquisition module is configured to define two modes in the mode group as a first mode and a second mode, respectively; and to acquire the first downstream propagation time and the first upstream propagation time under the first mode, and the second downstream propagation time and the second upstream propagation time under the second mode, respectively, through the received signal. The second calculation module is configured to calculate the volumetric flow rate under the mode group using the following formula; and to calculate the average flow rate based on the volumetric flow rate. in, ; ; Where, For volumetric flow rate, For the first downstream propagation time, For the first reverse propagation time, For the second downstream propagation time, This is the second retrograde propagation time. As the first coefficient, As the second coefficient, The third coefficient, For fluid flow velocity, The distance between the first probe and the second probe. Let be the radius of the pipe in the system under test.

[0088] In some embodiments, it also includes: The second correction module is configured to correct the volumetric flow rate by multiplying the volumetric flow rate by a pre-obtained calibration coefficient.

[0089] In some embodiments, when acquiring the calibration coefficients, the second correction module is specifically configured to: conduct a pre-experiment under experimental conditions to obtain the actual flow results of the current mode group within the calibration region under the experimental conditions. and calculation of flow results ; Based on the actual traffic results and the calculated flow results The calibration coefficients were calculated. ;in, .

[0090] In some embodiments, when obtaining the calibration coefficients, the second correction module is further configured to repeat the pre-experiment under different experimental conditions to obtain calibration coefficients under different experimental conditions, wherein the experimental conditions include at least the number of modes; correspondingly, before correcting the volumetric flow rate, the second correction module is further configured to obtain the current conditions and match the experimental conditions according to the current conditions to obtain the calibration coefficients matched under the current conditions.

[0091] In some embodiments, when the mode group division module selects at least three modes from the modes according to the mode selection quantity, it is specifically configured to determine whether the current mode meets the selection conditions. The selection conditions require that the amplitude of the received signal under the current mode is greater than a first preset amplitude threshold, and / or the signal length of the received signal under the current mode conforms to a first preset length threshold range. If so, the mode is selected; otherwise, the mode is not selected.

[0092] In some embodiments, the mode group division module is further configured to determine whether the amplitude of the received signal in the current mode is less than a second preset amplitude threshold. If so, the mode is selected; otherwise, the mode is not selected.

[0093] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0094] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A multi-modal ultrasonic flow fusion method, characterized in that: The following steps are involved: S200, using a first probe and a second probe to send a first transmission signal and a second transmission signal respectively, and correspondingly collecting a first reception signal and a second reception signal; wherein the first transmission signal or the second transmission signal generates at least three modes during the propagation process in the system to be measured, and the first reception signal or the second reception signal includes reception signals under the at least three modes; S201, selecting at least three modes from the modes generated in S200; S202, dividing the at least three modes selected in S201 into at least two mode groups, wherein one of the mode groups includes two modes; S203, defining two modes in the mode group as a first mode and a second mode respectively; obtaining a first downstream propagation time and a first upstream propagation time under the first mode, and a second downstream propagation time and a second upstream propagation time under the second mode respectively through the received signal, and calculating the volume flow under the mode group using the following model; in, ; ； In the formula, is the volume flow rate, is the first downstream propagation time, is the first countercurrent propagation time, is the second downstream propagation time, is the second countercurrent propagation time, is the first coefficient, is the second coefficient, is the third coefficient, is the fluid flow velocity, is the distance between the first probe and the second probe, is the pipe radius in the system to be measured; S205: Calculate a flow rate average based on at least two of the volume flow rates.

2. The multi-modal ultrasonic flow fusion method according to claim 1, characterized in that: Before S205, the step further includes: S204, correcting the volume flow, wherein the correction method is to multiply the volume flow by a pre-obtained calibration coefficient.

3. The multi-modal ultrasonic flow fusion method according to claim 2 is characterized in that: In S204, the method for obtaining the calibration coefficient includes: S41, performing a preliminary experiment under the experimental conditions to obtain actual flow results of the current mode group in the calibration area under the experimental conditions And the calculated flow results ; Wherein, the calibration area is an area corresponding to at least two modes among the multiple modes obtained through the preliminary experiment; S42, based on the actual flow result And the calculated flow results Calculate the calibration coefficient ; 。 4. The multi-modal ultrasonic flow fusion method according to claim 3 is characterized in that: When obtaining the calibration coefficient, the method further includes the following steps: S43, repeating the preliminary experiment under different experimental conditions to obtain calibration coefficients under different experimental conditions, wherein the experimental conditions at least include the number of modes; Accordingly, in S204, before correcting the volume flow, the method further includes: The current conditions are acquired, and the experimental conditions are matched according to the current conditions to obtain calibration coefficients matched under the current conditions.

5. The multi-modal ultrasonic flow fusion method according to claim 3, characterized in that: In S204, before the volume flow is corrected, the following steps are also included: S206, obtaining current conditions and matching the current conditions with the experimental conditions, the specific steps of which include: S61, obtaining at least three groups of received signals of at least three modes in a calibration area under current conditions, and at least three groups of standard received signals measured in at least three modes in the calibration area under experimental conditions; S62, respectively calculating the amplitude difference between the received signal and the standard received signal to obtain at least three amplitude difference values; S63, determining whether the at least three amplitude differences are all smaller than a first preset difference, and if so, matching the current condition with the experimental condition; S207, obtaining the calibration coefficient under the experimental conditions.

6. The multi-modal ultrasonic flow fusion method according to claim 1, characterized in that: In S201, the specific steps of selecting at least three modes include: determining whether the current mode satisfies a selection condition, wherein the selection condition requires that the amplitude of the received signal under the current mode is greater than a first preset amplitude threshold, and / or the signal length of the received signal under the current mode is within a first preset length threshold range; if so, the mode is selected, otherwise the mode is not selected.

7. A multi-modal ultrasonic flow fusion system, characterized in that: include: The second acquisition module is configured to respectively use the first probe and the second probe to send the first transmission signal and the second transmission signal, and correspondingly acquire the first reception signal and the second reception signal; wherein the first transmission signal or the second transmission signal generates at least three modes during the propagation process in the system to be measured, and the first reception signal or the second reception signal includes reception signals under the at least three modes; A second modality selection module: configured to select at least three modalities from the modalities collected by the second collection module; A modality group division module: configured to divide the at least three modalities selected by the second modality selection module into at least two modality groups, wherein one modality group includes two modalities; A data acquisition module: configured to define two modes in the mode group as a first mode and a second mode respectively; and to acquire a first downstream propagation time and a first upstream propagation time under the first mode, and a second downstream propagation time and a second upstream propagation time under the second mode respectively through the received signal; A second calculation module: configured to calculate the volume flow rate under the modal group using the following model; and to calculate the flow mean value according to at least two of the volume flow rates; in, ; ； In the formula, is the volume flow rate, is the first downstream propagation time, is the first countercurrent propagation time, is the second downstream propagation time, is the second countercurrent propagation time, is the first coefficient, is the second coefficient, is the third coefficient, is the fluid flow velocity, is the distance between the first probe and the second probe, is the pipe radius in the system to be tested.

8. The multi-modal ultrasonic flow fusion system according to claim 7, characterized in that: Also includes: The second correction module is configured to correct the volume flow by multiplying the volume flow by a pre-obtained calibration coefficient.

9. The multi-modal ultrasonic flow fusion system according to claim 8, characterized in that: When acquiring the calibration coefficient, the second correction module is specifically configured to: Conduct a preliminary experiment under the experimental conditions to obtain the actual flow results of the current mode group in the calibration area under the experimental conditions. And the calculated flow results ; Wherein, the calibration area is an area corresponding to at least two modes among the multiple modes obtained through the preliminary experiment; According to the actual flow results And the calculated flow results Calculate the calibration coefficient ;in, 。 10. The multi-modal ultrasonic flow fusion system according to claim 9, characterized in that: When acquiring the calibration coefficient, the second correction module is also configured to repeat the preliminary experiment under different experimental conditions to obtain the calibration coefficient under different experimental conditions, and the experimental conditions include at least the number of modes; accordingly, before correcting the volume flow, the second correction module is also configured to acquire the current conditions, match the experimental conditions according to the current conditions, and obtain the calibration coefficient matched under the current conditions.

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