A method of measuring a flow rate of an ultrasonic flow meter

Abstract

The present application relates to the technical field of fluid measurement, and more particularly to a measurement method of an ultrasonic flowmeter, comprising the steps of: using a criterion function to perform calculation, and selecting a corresponding measurement mode according to a corresponding interval to which a calculation result belongs; selecting a time difference method measurement mode: selecting a bubble processing model according to a state interval to which a current bubble state belongs to process collected data; selecting a Doppler method measurement mode: constructing an anti-interference measurement model, and then using the anti-interference measurement model to process collected data; selecting a parallel mode of the two methods: pre-processing data collected based on the time difference method and the Doppler method; then re-processing the above steps based on the pre-processed data of the two methods, and then performing dynamic weighted summation calculation. The present application can realize accurate self-adaptation between different measurement modes when facing complex fluid environments, can reduce systematic measurement errors, and improve measurement accuracy.

Description

Technical Field

[0001] This invention relates to the technical field of fluid measurement, and more specifically, to a measurement method using an ultrasonic flow meter. Background Technology

[0002] Ultrasonic flow meters, as core equipment for non-contact flow measurement, are widely used in water, chemical, environmental protection, and energy fields. In practical measurement scenarios, single time-of-flight or Doppler flow measurement methods are no longer sufficient to meet the ever-increasing measurement demands. Therefore, existing measurement methods, in addition to single measurement modes, also include modes that can combine time-of-flight and Doppler methods in parallel, adapting to dynamic measurement conditions by switching between different modes. However, existing measurement methods mostly rely on a rough judgment of the medium type for switching between measurement modes, failing to achieve accurate self-adaptation. Furthermore, when facing complex fluid environments where bubble interference and turbidity changes coexist, the flow measurement results still suffer from systematic measurement errors, and the measurement accuracy is insufficient to meet practical application requirements. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing technologies in achieving accurate self-adaptation between different measurement modes when facing complex fluid environments, and to provide a measurement method for ultrasonic flow meters that can achieve accurate self-adaptation between different measurement modes when facing complex fluid environments, thereby reducing systematic measurement errors and improving measurement accuracy.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A measurement method for an ultrasonic flow meter is provided, comprising the following steps: A criterion function is constructed based on the fluid state. The collected fluid data is then calculated using the criterion function, and the corresponding measurement mode is selected based on the interval to which the calculation result belongs. The processing method under the time difference measurement mode is as follows: Select the bubble processing model according to the current bubble state interval to process the collected data and then obtain the flow rate value; The processing method selected under the Doppler measurement mode is as follows: construct an anti-interference measurement model, then use the anti-interference measurement model to process the collected data, and then obtain the flow rate value; The processing method selected in the parallel mode of the two methods is as follows: the data collected by the time difference method and the Doppler method are preprocessed; then the above steps are reprocessed based on the preprocessed data of the two methods respectively, and then dynamic weighted summation is performed to obtain the final flow value.

[0005] Furthermore, the method for selecting the measurement mode includes the following steps: S11. Constructing a criterion function based on bubble state and fluid turbidity. :

[0006]

[0007] In the formula, Indicates fluid turbidity. , Indicates the upper limit of fluid turbidity. Indicates the bubble weighting factor. , This represents the number density of bubbles per unit volume. Indicates the maximum bubble density. Indicates the calibration coefficient. This represents the standard deviation of the current signal amplitude. This represents the baseline standard deviation of noise when there are no air bubbles. S12. Set the first criterion state value Second criterion state value ,in ; when When selecting the time difference method measurement mode; when When selecting the Doppler measurement mode; when At that time, the time difference method and the Doppler method were selected in parallel mode.

[0008] Furthermore, the processing method under the time difference measurement mode includes the following steps: S21. Set the first bubble state value Second bubble state value ,in ; S22. Construct a bubble shielding model and a bubble compensation model; S23. When the bubble state in the fluid is... When the bubble shielding model is used to correct the collected data, the corrected flow rate value is obtained and output; when the bubble state in the fluid is... When the bubble compensation model is used to reconstruct the collected data, the reconstructed flow rate value is obtained and output; when the bubble state in the fluid is... When the time comes, proceed to step S24; S24. The collected data are preprocessed using the bubble shielding model and the bubble compensation model respectively. Then, the preprocessed data is weighted and fused to obtain the fused flow value and output it.

[0009] Further, in step S22, the bubble shielding model is:

[0010] in:

[0011]

[0012] In the formula, This indicates a correction to the flow rate value. Indicates the time difference correction amount. Indicates the calibration coefficient. This represents the number density of bubbles per unit volume. Indicates the current fluid sound speed. This represents the speed of sound in a pure fluid. This represents the equivalent speed of sound in a fluid containing air bubbles. Indicates the sound path length of the time-of-flight flowmeter. Indicates the bubble compressibility factor; The bubble compensation model is as follows:

[0013]

[0014] In the formula, Indicates the reconstructed flow value. This represents the standard flow rate without air bubbles. Indicates the compensation gain coefficient. Represents the nonlinear steepness parameter. This represents the difference in bubble number density.

[0015] Further, in step S24, the weighted fusion calculation is as follows:

[0016] in,

[0017]

[0018] In the formula, This indicates a correction to the flow rate value. Indicates the reconstructed flow value. This represents the weighting coefficients of the bubble shielding model. This represents the weighting coefficients of the bubble compensation model.

[0019] Furthermore, in the processing method under the Doppler measurement mode, the anti-interference measurement model is as follows:

[0020]

[0021] In the formula, Indicates the compensation flow value. Indicates the cross-sectional area of ​​the flow path. Indicates the compensation flow rate. This indicates the flow velocity measured using the Doppler method; , , These represent the temperature compensation correction factor, pressure compensation correction factor, and bubble compensation correction factor, respectively. , These represent the calibration reference temperature value and the real-time acquired temperature value, respectively. , These represent the calibration reference pressure value and the real-time acquired pressure value, respectively. This represents the number density of bubbles per unit volume. This indicates the maximum bubble density.

[0022] Furthermore, the processing method in the parallel mode of the two methods includes the following steps: S41. Time reference synchronization: A unified nanosecond-level time reference is established for measurements using the time difference method and the Doppler method via the PTP protocol; S42. Data Acquisition and Preprocessing: Real-time acquisition of data actually measured by the time difference method and Doppler method, real-time acquisition of sensor layer observation data of the time difference method and Doppler method when measuring fluid, and acquisition of fluid turbidity data. Then, Kalman filtering algorithm is used to denoise the acquired data. Next, according to the data refresh rate of the time difference method and Doppler method when measuring fluid, linear interpolation method is used to resample the low-frequency data of Doppler method to the high-frequency time axis of time difference method, and then the nonlinear time offset is corrected by dynamic time warping algorithm. S43. Dynamic weighted fusion: The time difference method and Doppler method data preprocessed in step S42 are processed and calculated to obtain the preprocessed reconstructed flow rate value and the compensated flow rate value. Then, the two are subjected to basic weighted fusion calculation to obtain the basic fused flow rate. A turbidity-weighted mapping model is constructed using the fluid turbidity data preprocessed in step S42. Based on the sensing layer observation data preprocessed in step S42, dynamic modulation of signal quality is introduced to modulate the basic fusion weights to obtain the final flow rate value and output it.

[0023] Further, step S43 includes the following steps: S431. Set the basic fusion weights for the time difference method and the Doppler method, and then perform basic weighted fusion calculation on the preprocessed reconstructed flow value and the compensated flow value to obtain the basic fused flow; S432. Construct a turbidity-weighted mapping model using the fluid turbidity data preprocessed in step S42; S433. Introduce a signal confidence correction factor based on the real-time signal strength and average signal-to-noise ratio after preprocessing in step S42; S434. The basic fusion weights of the two methods are corrected by the signal confidence correction factor and the turbidity-weight mapping model to obtain the corrected fusion weights. Then, the final flow value is calculated based on the corrected fusion weights.

[0024] Further, in step S431, the basic weighted fusion calculation is as follows:

[0025]

[0026] In the formula, , These represent the basic fusion weights for the time difference method and the Doppler method, respectively; This represents the reconstructed flow rate value after preprocessing in step S42 and then reconstructing using the bubble compensation model. This represents the compensated flow rate value after preprocessing in step S42 and then compensation by the anti-interference measurement model. In step S432, the turbidity-weight mapping model is as follows:

[0027]

[0028] In the formula, This indicates the real-time fluid turbidity after preprocessing in step S42. Indicates the turbidity inflection point threshold. This represents the slope control parameter; In step S433, the signal confidence correction factor for:

[0029] In the formula, , These represent the real-time signal strengths under the time-difference method and the Doppler method after preprocessing in step S42, respectively. This represents the average signal-to-noise ratio within the current sampling window after preprocessing in step S42; , , All of these are calibration parameters.

[0030] Furthermore, in step S434, the time difference method is used to correct the fusion weights. Modified fusion weights for Doppler method They are respectively:

[0031]

[0032] Final flow value for:

[0033] In the formula, This represents the preset baseline weights for the time difference method.

[0034] This invention discloses a measurement method for an ultrasonic flow meter. By introducing the bubble state and fluid turbidity as criteria for selecting the measurement mode, it achieves more accurate operating condition identification. When selecting the time-of-flight (TOF) measurement mode, a corresponding bubble processing model is selected based on the current bubble state interval to process the acquired data, reducing measurement errors caused by bubble interference and improving flow measurement accuracy. When selecting the Doppler measurement mode, an anti-interference measurement model is constructed and used for data compensation processing, reducing measurement errors caused by temperature, pressure, and bubble interference, and improving flow measurement accuracy. When selecting the parallel two-method mode, both the TOF and Doppler data are preprocessed with noise reduction and time alignment to achieve accurate data timestamp alignment. Then, the preprocessed data from both methods are reprocessed according to the aforementioned steps, and the final flow value is obtained and output based on fluid turbidity and dynamic weighted summation. This invention enables accurate adaptation between different measurement modes in complex fluid environments, reducing systematic measurement errors and improving measurement accuracy. Attached Figure Description

[0035] Figure 1 This is a flowchart of a measurement method for an ultrasonic flow meter according to the present invention. Detailed Implementation

[0036] The present invention will be further described below with reference to specific embodiments. To enable those skilled in the art to better understand the present invention, the technical solutions of the embodiments will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0037] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects.

[0038] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification, claims and accompanying drawings of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products or devices.

[0039] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0040] Example 1 like Figure 1 The first embodiment of the measurement method of an ultrasonic flow meter according to the present invention is shown, which includes the following steps: Based on the bubble state and fluid turbidity, a criterion function is constructed. The collected fluid data is then calculated using the criterion function. The corresponding measurement mode is selected according to the interval to which the calculation result belongs. The measurement modes include time difference method measurement mode, Doppler method measurement mode, and parallel mode of two methods. The processing method selected under the time difference method measurement mode includes: selecting the corresponding bubble processing model according to the state interval to which the current bubble state belongs to process the collected data, and then outputting the processed flow value; The processing method selected under the Doppler measurement mode includes: constructing an anti-interference measurement model, then using the anti-interference measurement model to compensate the collected data, and finally obtaining and outputting the compensated flow value; The processing method selected in the parallel mode of the two methods includes: preprocessing the data collected by the time difference method and the Doppler method by denoising and time alignment; then reprocessing the data of the two methods based on the preprocessed data of the two methods respectively; and finally calculating the final flow rate value based on the fluid turbidity and dynamic weighted summation and outputting it.

[0041] This invention discloses a measurement method for an ultrasonic flow meter. By introducing the bubble state and fluid turbidity as criteria for selecting the measurement mode, it achieves more accurate operating condition identification. When selecting the time-of-flight (TOF) measurement mode, a corresponding bubble processing model is selected based on the current bubble state interval to process the acquired data, reducing measurement errors caused by bubble interference and improving flow measurement accuracy. When selecting the Doppler measurement mode, an anti-interference measurement model is constructed and used for data compensation processing, reducing measurement errors caused by temperature, pressure, and bubble interference, and improving flow measurement accuracy. When selecting the parallel two-method mode, both the TOF and Doppler data are preprocessed with noise reduction and time alignment to achieve accurate data timestamp alignment. Then, the preprocessed data from both methods are reprocessed according to the aforementioned steps, and the final flow value is obtained and output based on fluid turbidity and dynamic weighted summation. This invention enables accurate adaptation between different measurement modes in complex fluid environments, reducing systematic measurement errors and improving measurement accuracy.

[0042] In this embodiment, the method for selecting the measurement mode includes the following steps: S11. Constructing a criterion function based on bubble state and fluid turbidity. :

[0043]

[0044] In the formula, Indicates fluid turbidity. , Indicates the upper limit of fluid turbidity. Indicates the bubble weighting factor. , This represents the number density of bubbles per unit volume. Indicates the maximum bubble density. Indicates the calibration coefficient. This represents the standard deviation of the current signal amplitude. This represents the standard deviation of the noise baseline when there are no bubbles.

[0045] It should be noted that the number density of bubbles per unit volume Based on the current signal amplitude standard deviation Inversion, calibration coefficients Maximum bubble density can be obtained through calibration using a bubble generator. Upper limit of fluid turbidity All settings can be customized according to actual usage needs, and this is the preferred option. Can be set to , It can be set to 10000 NTU.

[0046] S12. Set the first criterion state value Second criterion state value ,in, As a preferred option, It can be set to 0.4. It can be set to 0.6; when When, select the time difference method measurement mode; when When, select the Doppler measurement mode; when At that time, the time difference method and the Doppler method were selected in parallel mode.

[0047] The processing method under the time difference method measurement mode includes the following steps: S21. Set the first bubble state value Second bubble state value ,in ; S22. Construct a bubble shielding model and a bubble compensation model; S23. When the bubble state in the fluid is... When the bubble shielding model is used to correct the collected data, the corrected flow rate value is obtained and output; when the bubble state in the fluid is... When the bubble compensation model is used to reconstruct the collected data, the reconstructed flow rate value is obtained and output; when the bubble state in the fluid is... When the time comes, proceed to step S24; S24. The collected data are preprocessed using the bubble shielding model and the bubble compensation model respectively. Then, the preprocessed data is weighted and fused to obtain the fused flow value and output it.

[0048] In this embodiment, in step S21, preferably, Can be set to , Can be set to ; In this embodiment, the bubble shielding model in step S22 is:

[0049] in:

[0050]

[0051] In the formula, This indicates a correction to the flow rate value. Indicates the time difference correction amount. Indicates the calibration coefficient. This represents the number density of bubbles per unit volume. Indicates the current fluid sound speed. This represents the speed of sound in a pure fluid (such as water at room temperature). This represents the equivalent speed of sound in a fluid containing air bubbles. Indicates the sound path length of the time-of-flight flowmeter. This represents the bubble compressibility factor; it should be noted that this is a calibration factor. It can be obtained through laboratory calibration; The bubble compensation model is as follows:

[0052]

[0053] In the formula, Indicates the reconstructed flow value. This represents the standard flow rate without air bubbles. Indicates the compensation gain coefficient. Represents the nonlinear steepness parameter. This represents the difference in bubble number density; it should be noted that this is the standard flow rate without bubbles. Can be obtained through calibration; compensation gain coefficient Ideally, it should reflect the intensity of the response to a high bubble state. It can be set to 0.35; nonlinear steepness parameter It can be used to control the transition sharpness of the compensation curve, and is therefore preferred. It can be set to 0.6.

[0054] S23. When the bubble state in the fluid is... When using a bubble shielding model, linear compensation for sound velocity distortion is performed through bubble density, which corrects the collected data, yields the corrected flow rate value, and outputs it. When the bubble state in the fluid is... At that time, the collected data is reconstructed using a bubble compensation model through a nonlinear function, and the reconstructed flow rate value is then output; when the bubble state in the fluid is in the threshold transition region, i.e. When the time comes, proceed to step S24; In this embodiment, the weighted fusion calculation in step S24 is as follows:

[0055] in,

[0056]

[0057] In the formula, This indicates a correction to the flow rate value. Indicates the reconstructed flow value. This represents the weighting coefficients of the bubble shielding model. This represents the weighting coefficients of the bubble compensation model; the aforementioned weighting mechanism ensures seamless model switching in the threshold transition region, avoids measurement jumps, and improves the robustness of the measurement method.

[0058] Example 2 This embodiment is a second embodiment of an ultrasonic flowmeter measurement method. This embodiment is similar to the first embodiment, except that in this embodiment, the measurement method of the present invention can use a time-difference flowmeter for data acquisition in the time-difference measurement mode, a Doppler flowmeter for data acquisition in the Doppler measurement mode, a turbidity meter for fluid turbidity acquisition, and a data processor for receiving and analyzing the data acquired by the time-difference flowmeter, Doppler flowmeter, and turbidity meter. It should be noted that the measurement method of the present invention can also use a display device connected to the data processor, and the output flow value after analysis and processing can be displayed on the display device.

[0059] In the processing method under the Doppler measurement mode, the anti-interference measurement model is as follows:

[0060]

[0061] In the formula, Indicates the compensation flow value. Indicates the cross-sectional area of ​​the flow path. Indicates the compensation flow rate. This indicates the flow velocity directly measured by a Doppler flow meter; , , These represent the temperature compensation correction factor, pressure compensation correction factor, and bubble compensation correction factor, respectively. , These represent the calibration reference temperature value and the real-time acquired temperature value, respectively. , These represent the calibration reference pressure value and the real-time acquired pressure value, respectively. This represents the number density of bubbles per unit volume. This indicates the maximum bubble density.

[0062] Example 3 This embodiment is a third embodiment of a measurement method for an ultrasonic flow meter. This embodiment is similar to Embodiment 1 or 2, except that the processing method in the parallel mode of the two methods in this embodiment includes the following steps: S41. Time Reference Synchronization: Time is synchronized for time difference flow meters, Doppler flow meters, turbidity meters, and data processors via the PTP protocol, establishing a unified nanosecond-level time reference; specifically, the PTP protocol uses hardware timestamps (PHC) to provide a unified time reference for time difference flow meters, Doppler flow meters, turbidity meters, and data processors with nanosecond-level accuracy. S42. Data Acquisition and Preprocessing: Real-time acquisition of data actually measured by time-of-flight (TOF) flow meters and Doppler flow meters; real-time acquisition of sensor layer observation data of TOF and Doppler flow meters during fluid measurement; acquisition of fluid turbidity data measured by turbidimeter; and then using Kalman filtering algorithm to denoise the acquired data. Next, based on the data refresh rate of TOF and Doppler flow meters during fluid measurement, linear interpolation method is used to resample the low-frequency data of Doppler flow meters to the high-frequency time axis of TOF flow meters. Then, dynamic time warping algorithm is used to correct nonlinear time offset to ensure that the timestamp deviation of all data is ≤1μs. S43. Dynamic Weighted Fusion: The time-difference method and Doppler method data preprocessed in step S42 are processed and calculated separately to obtain the preprocessed reconstructed flow rate value and the compensated flow rate value. Then, a basic weighted fusion calculation is performed on the two to obtain the basic fused flow rate. A turbidity-weighted mapping model is constructed using the fluid turbidity data preprocessed in step S42. Based on the sensing layer observation data preprocessed in step S42, dynamic signal quality modulation is introduced to modulate the basic fusion weights to obtain the final flow rate value and output it. In this embodiment, step S43 includes the following steps: S431. Set the basic fusion weights for the time difference method and the Doppler method, and then perform basic weighted fusion calculation on the preprocessed reconstructed flow value and the compensated flow value to obtain the basic fused flow; specifically: The basic weighted fusion calculation is as follows:

[0063]

[0064] In the formula, , These represent the basic fusion weights for the time difference method and the Doppler method, respectively. , ; This represents the reconstructed flow rate value after preprocessing in step S42 and then reconstructing using the bubble compensation model. This represents the compensated flow rate value after preprocessing in step S42 and then after compensation processing by the anti-interference measurement model. S432. Construct a turbidity-weighted mapping model using the fluid turbidity data preprocessed in step S42; specifically: The turbidity-weight mapping model is as follows:

[0065]

[0066] In the formula, This indicates the real-time fluid turbidity after preprocessing in step S42; It represents the turbidity inflection point threshold, which is the critical transition zone between clean and turbid fluids; This represents the slope control parameter, which can be used to control the smoothness of weight changes; where, when When the value approaches 0, the measurement method will rely on the time difference measurement mode; when Approaching At that time, the measurement method will rely on the Doppler measurement mode, when hour, To achieve a natural transition; S433. Based on the real-time signal strength and average signal-to-noise ratio after preprocessing in step S42, a signal confidence correction factor is introduced; specifically: Signal confidence correction factor for:

[0067] In the formula, , These represent the real-time signal strengths under the time difference method and Doppler method after preprocessing in step S42, respectively, and can be normalized to 0~1; This represents the average signal-to-noise ratio within the current sampling window after preprocessing in step S42; , , These are all calibration parameters, such as, It can be set to 30dB. It can be set to 15dB; S434. The basic fusion weights of the two methods are corrected using a signal confidence correction factor and a turbidity-weight mapping model to obtain corrected fusion weights. The final flow value is then calculated based on these corrected fusion weights. Specifically: Time difference method modified fusion weight Modified fusion weights for Doppler method They are respectively:

[0068]

[0069] Final flow value for:

[0070] In the formula, The preset baseline weights for the time difference method are preferred. It can be set to 0.8.

[0071] In the specific implementation of the above embodiments, the technical features can be combined in any non-contradictory way. For the sake of brevity, not all possible combinations of the above technical features are described. However, as long as the combination of these technical features is not contradictory, it should be considered to be within the scope of this specification.

[0072] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A measurement method for an ultrasonic flow meter, characterized in that, The steps include the following: A criterion function is constructed based on the fluid state. The collected fluid data is processed using the criterion function, and the corresponding measurement mode is selected according to the interval to which the processing result belongs. The processing method selected under the time difference measurement mode is as follows: Select the bubble processing model according to the current bubble state interval to process the collected data, and then obtain the flow rate value; The processing method selected under the Doppler measurement mode is as follows: construct an anti-interference measurement model, then use the anti-interference measurement model to process the collected data, and then obtain the flow rate value; The processing method selected in the parallel mode of the two methods is as follows: the data collected by the time difference method and the Doppler method are preprocessed; then the above steps are reprocessed based on the preprocessed data of the two methods respectively, and then dynamic weighted summation is performed to obtain the final flow value.

2. The measurement method of the ultrasonic flow meter according to claim 1, characterized in that, The method for selecting the measurement mode includes the following steps: S11. Constructing a criterion function based on bubble state and fluid turbidity. : In the formula, Indicates fluid turbidity. , Indicates the upper limit of fluid turbidity. Indicates the bubble weighting factor. , This represents the number density of bubbles per unit volume. Indicates the maximum bubble density. Indicates the calibration coefficient. This represents the standard deviation of the current signal amplitude. This represents the baseline standard deviation of noise when there are no air bubbles. S12. Set the first criterion state value Second criterion state value ,in ; when At that time, select the time difference method measurement mode; when When selecting the Doppler measurement mode; when At that time, the time difference method and the Doppler method were selected in parallel mode.

3. The measurement method of the ultrasonic flow meter according to claim 1, characterized in that, The processing method under the time difference measurement mode includes the following steps: S21. Set the first bubble state value Second bubble state value ,in ; S22. Construct a bubble shielding model and a bubble compensation model; S23. When the bubble state in the fluid is... When the bubble shielding model is used to correct the collected data, the corrected flow rate value is obtained and output; when the bubble state in the fluid is... When the bubble compensation model is used to reconstruct the collected data, the reconstructed flow rate value is obtained and output; when the bubble state in the fluid is... When the time comes, proceed to step S24; S24. The collected data are preprocessed using the bubble shielding model and the bubble compensation model respectively. Then, the preprocessed data is weighted and fused to obtain the fused flow value and output it.

4. The measurement method of the ultrasonic flow meter according to claim 3, characterized in that, In step S22, the bubble shielding model is as follows: in: In the formula, This indicates a correction to the flow rate value. Indicates the time difference correction amount. Indicates the calibration coefficient. This represents the number density of bubbles per unit volume. Indicates the current fluid sound speed. This represents the speed of sound in a pure fluid. This represents the equivalent speed of sound in a fluid containing air bubbles. Indicates the sound path length of the time-of-flight flowmeter. Indicates the bubble compressibility factor; The bubble compensation model is as follows: In the formula, Indicates the reconstructed flow value. This represents the standard flow rate without air bubbles. Indicates the compensation gain coefficient. Represents the nonlinear steepness parameter. This represents the difference in bubble number density.

5. The measurement method of the ultrasonic flow meter according to claim 4, characterized in that, In step S24, the weighted fusion calculation is as follows: in, In the formula, This indicates a correction to the flow rate value. Indicates the reconstructed flow value. This represents the weighting coefficients of the bubble shielding model. This represents the weighting coefficients of the bubble compensation model.

6. The measurement method of the ultrasonic flow meter according to claim 1, characterized in that, In the processing method under the Doppler measurement mode, the anti-interference measurement model is as follows: In the formula, Indicates the compensation flow value. Indicates the cross-sectional area of ​​the flow path. Indicates the compensation flow rate. This indicates the flow velocity measured using the Doppler method; , , These represent the temperature compensation correction factor, pressure compensation correction factor, and bubble compensation correction factor, respectively. , These represent the calibration reference temperature value and the real-time acquired temperature value, respectively. , These represent the calibration reference pressure value and the real-time acquired pressure value, respectively. This represents the number density of bubbles per unit volume. This indicates the maximum bubble density.

7. The measurement method of the ultrasonic flow meter according to claim 1, characterized in that, The processing method in the parallel mode of two methods includes the following steps: S41. Time reference synchronization: A unified nanosecond-level time reference is established for measurements using the time difference method and the Doppler method via the PTP protocol; S42. Data Acquisition and Preprocessing: Real-time acquisition of data actually measured by the time difference method and Doppler method, real-time acquisition of sensor layer observation data of the time difference method and Doppler method when measuring fluid, and acquisition of fluid turbidity data. Then, Kalman filtering algorithm is used to denoise the acquired data. Next, according to the data refresh rate of the time difference method and Doppler method when measuring fluid, linear interpolation method is used to resample the low-frequency data of Doppler method to the high-frequency time axis of time difference method, and then the nonlinear time offset is corrected by dynamic time warping algorithm. S43. Dynamic weighted fusion: The time difference method and Doppler method data after preprocessing in step S42 are processed and calculated to obtain the preprocessed reconstructed flow value and the compensated flow value. Then, the two are subjected to basic weighted fusion calculation to obtain the basic fused flow. A turbidity-weighted mapping model is constructed using the fluid turbidity data preprocessed in step S42. Based on the sensor layer observation data preprocessed in step S42, dynamic modulation of signal quality is introduced to modulate the basic fusion weights, and the final flow value is obtained and output.

8. The measurement method of the ultrasonic flow meter according to claim 6, characterized in that, Step S43 includes the following steps: S431. Set the basic fusion weights for the time difference method and the Doppler method, and then perform basic weighted fusion calculation on the preprocessed reconstructed flow value and the compensated flow value to obtain the basic fused flow; S432. Construct a turbidity-weighted mapping model using the fluid turbidity data preprocessed in step S42; S433. Introduce a signal confidence correction factor based on the real-time signal strength and average signal-to-noise ratio after preprocessing in step S42; S434. The basic fusion weights of the two methods are corrected by the signal confidence correction factor and the turbidity-weight mapping model to obtain the corrected fusion weights. Then, the final flow value is calculated based on the corrected fusion weights.

9. The measurement method of the ultrasonic flow meter according to claim 8, characterized in that, In step S431, the basic weighted fusion calculation is as follows: In the formula, , These represent the basic fusion weights for the time difference method and the Doppler method, respectively; This represents the reconstructed flow rate value after preprocessing in step S42 and then reconstructing using the bubble compensation model. This represents the compensated flow rate value after preprocessing in step S42 and then compensation by the anti-interference measurement model. In step S432, the turbidity-weight mapping model is as follows: In the formula, This indicates the real-time fluid turbidity after preprocessing in step S42. Indicates the turbidity inflection point threshold. This represents the slope control parameter; In step S433, the signal confidence correction factor for: In the formula, , These represent the real-time signal strengths under the time-difference method and the Doppler method after preprocessing in step S42, respectively. This represents the average signal-to-noise ratio within the current sampling window after preprocessing in step S42; , , All of these are calibration parameters.

10. The measurement method of the ultrasonic flow meter according to claim 8, characterized in that, In step S434, the time difference method is used to correct the fusion weights. Modified fusion weights for Doppler method They are respectively: Final flow value for: In the formula, This represents the preset baseline weights for the time difference method.

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