Two-phase flow analysis system and method based on differential pressure flowmeter and electromagnetic flowmeter

Abstract

The invention belongs to the technical field of flowmeter verification, and discloses a two-phase flow analysis system and method based on a differential pressure flowmeter and an electromagnetic flowmeter. The method comprises the steps that a differential pressure flow meter and an electromagnetic flow meter are arranged on adjacent sections of a pipeline, the electromagnetic flow meter collects voltage signals and analyzes the voltage signals to obtain liquid phase volume flow, and liquid phase mass flow is obtained by combining temperature correction; the differential pressure flowmeter calculates the gas density by using an ideal gas law according to the temperature and the pressure; inputting multi-sensor time sequence data into the weight optimization model, and optimizing the volume gas content and the total mass flow rate; baseline parameters are calibrated during full-pipe single-phase flow to obtain zero drift, and real-time temperature and pressure dynamic correction are combined, so that the metering precision and the working condition adaptability are improved; the problem of verification deviation of a traditional flowmeter is solved, high precision and high reliability of complex gas-liquid two-phase flow metering are achieved, and efficient and reliable technical support is provided for two-phase flow precise metering and process control in the fields of chemical engineering, energy and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of flowmeter calibration, and more specifically, to a two-phase flow analysis system and method based on a differential pressure flowmeter and an electromagnetic flowmeter. Background Art

[0002] In industrial production, such as in the fields of petroleum, chemical industry, and energy, it is often necessary to accurately measure gas-liquid two-phase flow or liquid-solid two-phase flow, etc. Traditional flow measurement methods and devices have many problems when faced with two-phase flow, and it is difficult to meet the measurement requirements of high precision and high reliability.

[0003] For example, some conventional flowmeters cannot accurately measure the flow rate distribution of each phase in two-phase flow, resulting in a large overall measurement error; some devices have a complex structure, high maintenance costs, and are not suitable for measuring two-phase flow under different working conditions.

[0004] The Chinese patent with the authorization publication number CN102997979B discloses a differential pressure flowmeter calibration system; the system includes an industrial computer, a differential pressure calibration module, an electromagnetic flowmeter standard meter, and a HART converter; the differential pressure calibration module includes a data processing module and a control module and is built into the industrial computer; one end of the HART converter is connected to the HART interface built in the differential pressure flowmeter transmitter to be calibrated, and the other end is connected to the data processing module of the differential pressure calibration module through a computer interface; the electromagnetic flowmeter standard meter is connected to the industrial computer through its own RS232 data interface, wherein the HART converter can mutually convert the HART protocol physical signal used by the differential pressure flowmeter to be calibrated and the RS-232 serial signal of the industrial computer; the data processing module can read and display the data of the differential pressure flowmeter to be calibrated and the electromagnetic flowmeter standard meter, wherein the basic information of the differential pressure flowmeter to be calibrated includes the manufacturer identification code, the manufacturer equipment type code, and the equipment identification number, as well as the differential pressure value, current value, and flow percentage during the calibration process; the basic information of the electromagnetic flowmeter standard meter includes the instantaneous flow rate and the cumulative flow rate. This invention avoids the systematic error in the data acquisition stage of the calibration table and the errors caused by some incorrect operations, improves the accuracy of the calibration result, and improves the work efficiency.

[0005] Although the above method can meet most scenarios, through research and practical application of the above method and the existing technology, it is found that the above method and the existing technology have at least the following partial defects:

[0006] Collecting the current signal of the differential pressure flowmeter through a current-voltage conversion circuit and an analog-to-digital conversion module (AD module) has hardware errors and AD sampling resolution errors, and at the same time, the calculation error during the transmitter's processing of the instantaneous flow rate will also cause calibration deviation.

[0007] In view of this, the present invention proposes a two-phase flow analysis system and method based on a differential pressure flowmeter and an electromagnetic flowmeter to solve the above problems. Summary of the Invention

[0008] To overcome the above-mentioned defects of the prior art and to achieve the above object, the present invention provides the following technical solutions: A two-phase flow analysis method based on a differential pressure flowmeter and an electromagnetic flowmeter, comprising the following steps:

[0009] Install a differential pressure flowmeter and an electromagnetic flowmeter at adjacent cross-sections of the pipeline;

[0010] Collect the voltage signal of the electromagnetic flowmeter, and calculate the liquid-phase mass flow rate by combining the liquid thermal expansion coefficient and the density of the liquid at the reference temperature.

[0011] Collect the temperature and pressure of the fluid in the pipeline, calculate the gas density according to the temperature and pressure using the ideal gas law, and calculate the total mass flow rate according to the gas density.

[0012] Use the multi-sensor time-series data as the input of the weight optimization model to obtain the optimized volume gas holdup and total mass flow rate; the multi-sensor time-series data includes differential pressure, voltage, temperature and pressure.

[0013] In the full-pipe single-phase flow state, determine whether it meets the preset trigger condition. If it meets, calibrate the baseline parameters of the differential pressure flowmeter and the electromagnetic flowmeter to obtain the zero-point drift corresponding to the differential pressure flowmeter and the electromagnetic flowmeter, and update the corresponding flowmeter parameters according to the zero-point drift.

[0014] Combine the real-time temperature and real-time pressure to dynamically correct the zero-point drift corresponding to the differential pressure flowmeter and the electromagnetic flowmeter, and the flowmeter parameters corresponding to the zero-point drift.

[0015] Further, the method for obtaining the liquid-phase mass flow rate includes:

[0016] Collect the voltage signal of the electromagnetic flowmeter, analyze to obtain the liquid-phase volume flow rate, combine the liquid thermal expansion coefficient and the density of the liquid at the reference temperature to calculate the corrected liquid density, and calculate the product of the corrected liquid density and the liquid-phase volume flow rate to obtain the liquid-phase mass flow rate.

[0017] Further, the method for calculating the total mass flow rate includes:

[0018] Initialize the volume gas holdup, calculate the average density according to the initialized volume gas holdup, in combination with the gas density and the corrected liquid density, and calculate the initial total mass flow rate in combination with the differential pressure collected by the differential pressure flowmeter, the liquid-phase mass flow rate, the structural coefficient and the average density.

[0019] An updated gas volume fraction is calculated based on the gas mass flow rate, the liquid phase volume flow rate, the corrected liquid density, and the gas density. The initial total mass flow rate is updated according to the updated gas volume fraction to obtain an updated total mass flow rate. The gas volume fraction and the total mass flow rate are repeatedly updated until the change difference of the total mass flow rate is less than a preset change threshold, and the last updated total mass flow rate is used as the final total mass flow rate.

[0020] Further, the method for determining whether the preset trigger condition is met includes:

[0021] For the preset trigger condition, when the trigger condition is met, the real-time flow calculation is paused, and the baseline parameters of the differential pressure flowmeter and the electromagnetic flowmeter are calibrated.

[0022] Further, the method for calibrating the baseline parameters of the differential pressure flowmeter includes:

[0023] In the state where the differential pressure flowmeter has no flow, the zero drift output by the differential pressure flowmeter is collected N times, and the average value of the zero drift output by the differential pressure flowmeter N times is calculated as the zero drift of the differential pressure.

[0024] In the state of known flow, the differential pressure of the differential pressure flowmeter is recorded, the difference between the differential pressure and the zero drift of the differential pressure is calculated, and it is marked as the actual differential pressure.

[0025] A differential pressure-flow relationship regarding the structure coefficient, the actual differential pressure, and the known flow is established, and the value of the corresponding structure coefficient is calculated according to the differential pressure-flow relationship. The value of the corresponding structure coefficient is used as the flowmeter parameter corresponding to the differential pressure flowmeter.

[0026] Further, the method for calibrating the baseline parameters of the electromagnetic flowmeter includes:

[0027] In the state where the electromagnetic flowmeter has no flow, the zero drift of the output voltage of the electromagnetic flowmeter is collected N times, and the average value of the zero drift of the output voltage of the electromagnetic flowmeter N times is calculated as the zero drift of the voltage.

[0028] In the state of known flow, the voltage of the electromagnetic flowmeter is recorded, the difference between the voltage and the zero drift of the voltage is calculated, and it is marked as the actual voltage.

[0029] A voltage-flow velocity relationship regarding the sensitivity coefficient of the electromagnetic flowmeter, the actual voltage, the pipe cross-sectional area, and the known flow is established, and the sensitivity coefficient of the electromagnetic flowmeter is calculated according to the voltage-flow velocity relationship; the sensitivity coefficient of the electromagnetic flowmeter is used as the flowmeter parameter corresponding to the electromagnetic flowmeter.

[0030] Further, the method for updating the corresponding flowmeter parameters according to the zero drift includes:

[0031] Based on the temperature coefficients of the differential pressure flowmeter and the electromagnetic flowmeter, dynamically correct the outputs of the differential pressure flowmeter and the electromagnetic flowmeter.

[0032] Furthermore, the method for dynamically correcting the zero drift corresponding to the differential pressure flowmeter and the electromagnetic flowmeter includes:

[0033] Update the zero drift of the differential pressure flowmeter and the electromagnetic flowmeter according to the zero drift of the differential pressure flowmeter and the electromagnetic flowmeter, combined with the proportional gain and the real-time error, to obtain the updated zero drift of the differential pressure flowmeter and the electromagnetic flowmeter.

[0034] Furthermore, the method for dynamically correcting the flowmeter parameters corresponding to the zero drift includes:

[0035] Update the sensitivity coefficient of the electromagnetic flowmeter according to the reference flow deviation and the flow deviation to obtain the updated sensitivity coefficient of the electromagnetic flowmeter;

[0036] Under the standard temperature, calibrate the initial temperature drift coefficient, collect the real-time temperature, calculate the difference between the real-time temperature and the standard temperature to obtain the temperature change;

[0037] Under the preset working conditions, fix the flow rate and change the temperature, and record the pressure drift corresponding to the temperature change;

[0038] Calculate the temperature drift coefficient compensation value according to the temperature change and the pressure drift.

[0039] Furthermore, the method for obtaining the liquid-phase volume flow rate includes:

[0040] Collect the voltage signal of the electromagnetic flowmeter, calculate the product of the voltage signal and the pipe cross-sectional area to obtain the liquid-phase volume flow rate.

[0041] Implement the two-phase flow analysis method based on the differential pressure flowmeter and the electromagnetic flowmeter in a two-phase flow analysis system based on the differential pressure flowmeter and the electromagnetic flowmeter, including:

[0042] Device building module: Install a differential pressure flowmeter and an electromagnetic flowmeter at adjacent cross-sections of the pipeline;

[0043] First analysis module: Collect the voltage signal of the electromagnetic flowmeter, analyze and obtain the liquid-phase volume flow rate, combine the liquid thermal expansion coefficient and the density of the liquid at the reference temperature, calculate the corrected liquid density, and calculate the liquid-phase mass flow rate based on the corrected liquid density and the liquid-phase volume flow rate;

[0044] Second analysis module: Collect the temperature and pressure of the fluid in the pipeline, calculate the gas density according to the temperature and pressure using the ideal gas law, and calculate the total mass flow rate according to the gas density;

[0045] Third analysis module: Using the multi-sensor time-series data as the input of the weight optimization model to obtain the optimized volumetric gas holdup and total mass flow rate; the multi-sensor time-series data includes differential pressure, voltage, temperature, and pressure.

[0046] Static calibration module: Under the full-pipe single-phase flow state, determine whether it meets the preset trigger condition. If it meets, calibrate the baseline parameters of the differential pressure flowmeter and the electromagnetic flowmeter to obtain the zero drift corresponding to the differential pressure flowmeter and the electromagnetic flowmeter, and update the corresponding flowmeter parameters according to the zero drift.

[0047] Feedback correction module: Combining the real-time temperature and real-time pressure, dynamically correct the zero drift corresponding to the differential pressure flowmeter and the electromagnetic flowmeter, as well as the flowmeter parameters corresponding to the zero drift.

[0048] Technical effects and advantages of the two-phase flow analysis system and method based on differential pressure flowmeter and electromagnetic flowmeter of the present invention:

[0049] In the present invention, two types of flowmeters are collaboratively deployed at adjacent cross-sections of the pipeline. The electromagnetic flowmeter directly collects the liquid-phase voltage signal and combines temperature correction to accurately calculate the liquid-phase mass flow rate, eliminating the influence of temperature on liquid density. The differential pressure flowmeter jointly models the gas density with temperature and pressure parameters to provide key gas-phase parameters for the total mass flow rate calculation. By introducing a weight optimization model, deeply excavate the coupling relationship of multi-sensor time-series data such as differential pressure, voltage, temperature, and pressure, and optimize the volumetric gas holdup and total mass flow rate in real time, significantly improving the measurement adaptability under complex flow patterns. At the same time, through the baseline parameter calibration triggered by full-pipe single-phase flow and the temperature and pressure dynamic compensation mechanism, continuously calibrate the zero error and temperature drift of the sensor to ensure the output stability of the flowmeter under different working conditions. The present invention solves the calibration deviation problem of traditional differential pressure flowmeters and electromagnetic flowmeters through multi-dimensional technology integration, realizes high-precision and high-reliability measurement of complex gas-liquid two-phase flow, and provides efficient and reliable technical support for accurate measurement and process control of two-phase flow in fields such as chemical industry and energy. Description of the Drawings

[0050] Figure 1 It is a schematic diagram of the two-phase flow analysis method based on differential pressure flowmeter and electromagnetic flowmeter of the present invention;

[0051] Figure 2 It is an installation schematic diagram of the differential pressure flowmeter and the electromagnetic flowmeter of the present invention;

[0052] Figure 3 It is a schematic diagram of the gas-liquid distribution in the swirl device of the present invention;

[0053] Figure 4 It is a schematic diagram of the temperature and pressure sensor layout of the Venturi tube flowmeter of the present invention;

[0054] Figure 5 Schematic diagram of the signal processing flow of the present invention;

[0055] Figure 6 Structural diagram of the two-phase flow analysis system based on differential pressure flowmeter and electromagnetic flowmeter of the present invention.

[0056] Reference numerals: 1, swirl device; 2, electromagnetic flowmeter; 3, Venturi tube; 4, pressure sensor; 5, differential pressure flowmeter; 6, temperature sensor. Specific embodiments

[0057] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0058] Embodiment 1:

[0059] Please refer to Figure 1 As shown, this embodiment provides a two-phase flow analysis method based on a differential pressure flowmeter and an electromagnetic flowmeter, including the following steps:

[0060] Install a differential pressure flowmeter 5 (such as a Venturi tube 3) and an electromagnetic flowmeter 2 at adjacent cross-sections of the pipeline;

[0061] For the specific device schematic diagram, reference can be made to Figure 2 , where the swirl device 1 is installed upstream of the pipeline to force the gas-liquid to form a stratified flow. Reference can be made to Figure 3 . The cone angle of the guide cylinder inside the swirl device 1 is set to 30° - 60° to adapt to different gas-liquid ratio working conditions. The diameter of the guide cylinder is 1 - 3 times the pipe diameter, and the pitch of the spiral blade is adjustable. It can force the gas-liquid to rotate, separate the gas-liquid by centrifugal force, form a central gas column and an outer liquid ring. The swirl device 1 can achieve efficient gas-liquid pre-separation and reduce the measurement interference of the sensor; downstream, it is sequentially connected to the electromagnetic flowmeter 2 and the Venturi tube 3; the electromagnetic flowmeter 2 is used to measure the total volume flow of the two-phase flow; the Venturi tube 3 uses its special structure to obtain the flow velocity information of each phase in the two-phase flow by measuring the pressure difference before and after. Refer to Figure 4 . The Venturi tube 3 integrates a differential pressure sensor, a temperature sensor 6 and a pressure sensor 4, and is symmetrically embedded on both sides of the pipe wall to monitor the fluid physical property parameters in real time.

[0062] Refer to Figure 5, when the two-phase flow passes through the electromagnetic flowmeter 2, according to the principle of electromagnetic induction, the electromagnetic flowmeter 2 outputs an electrical signal proportional to the total volume flow. Then, the fluid enters the Venturi tube 3. In the contraction section and the throat of the Venturi tube 3, due to the change in pipe diameter, the flow velocity increases and the pressure decreases. By measuring the pressure difference between the inlet and the throat of the Venturi tube 3 and combining with the pre-established relationship model between the pressure difference and the flow velocity, the flow velocity of each phase can be calculated. The data processing unit receives the signals transmitted from the electromagnetic flowmeter 2 and the Venturi tube 3, analyzes and processes the signals through a specific algorithm, and finally obtains the gas flow rate, liquid flow rate and total flow rate in the two-phase flow.

[0063] For Figure 2 the device in is tested under M groups of the same test conditions as the traditional orifice plate method (the test conditions for each group are the same, and the average value of the test results of M groups is taken as the final test result). The test results can be referred to Table 1:

[0064] Table 1 Performance parameters of different devices under the same test conditions

[0065] Test conditions Traditional orifice plate method This device Gas-liquid ratio 1:1 1:1 Pressure fluctuation 5 5 Temperature deviation 10 10 Volume flow rate error ±4.2 ±1.2

[0066] It can be seen from Table 1 that the volume flow error of the device adopted in this embodiment is ±1.2, and the volume flow error of the traditional orifice plate method is ±4.2. The volume flow error of the device adopted in this embodiment is lower, with higher measurement accuracy, and can provide more accurate data for two-phase flow analysis, thus more effectively assisting the relevant fields to accurately grasp and deeply study the flow situation, and improving the accuracy and reliability of the analysis.

[0067] Collect the voltage signal of the electromagnetic flowmeter 2, analyze to obtain the liquid-phase volume flow rate, combine with the liquid thermal expansion coefficient and the density of the liquid at the reference temperature, calculate to obtain the corrected liquid density, and calculate the liquid-phase mass flow rate based on the corrected liquid density and the liquid-phase volume flow rate; by correcting the density parameter with temperature, convert the volume flow rate measured by the electromagnetic flowmeter 2 into a more accurate mass flow rate, effectively improving the measurement accuracy of the liquid-phase mass flow rate in the two-phase flow and providing reliable flow data support for fields such as industrial process control and energy metering.

[0068] The method for obtaining the liquid-phase volume flow rate includes:

[0069] Collect the voltage signal of the electromagnetic flowmeter 2, calculate the product of the voltage signal and the pipe cross-sectional area, and obtain the liquid-phase volume flow rate.

[0070] The electromagnetic flowmeter 2 directly obtains the liquid-phase volume flow rate by collecting voltage signals and combining with the pipeline cross-sectional area, laying a foundation for the measurement of liquid-phase parameters; the differential pressure flowmeter 5 captures the pressure difference changes in the two-phase flow to reflect the overall flow characteristics; the combination of the two can take into account both the accurate measurement of the liquid-phase volume flow rate and the analysis of the comprehensive flow state of the two-phase flow. It can not only calculate the liquid-phase mass flow rate through the liquid-phase volume flow rate and the corrected density, but also analyze the influence of the gas phase based on the differential pressure characteristics, effectively reducing the measurement error of a single flowmeter in a multiphase flow environment and improving the comprehensiveness and reliability of flow measurement under complex working conditions.

[0071] The methods for obtaining the liquid-phase mass flow rate include:

[0072] Combining the liquid thermal expansion coefficient and the density of the liquid at the reference temperature, calculating to obtain the corrected density of the liquid, and calculating the product of the corrected density of the liquid and the liquid-phase volume flow rate to obtain the liquid-phase mass flow rate; if the corrected density of the liquid The calculation formula is: ; where is the liquid thermal expansion coefficient, which can be obtained by optimizing through a nature-inspired optimization algorithm; is the density of the liquid at the reference temperature; is the temperature; is the reference temperature.

[0073] Collect the temperature and pressure of the fluid in the pipeline, and calculate the gas density according to the temperature and pressure using the ideal gas law, and calculate the total mass flow rate according to the gas density.

[0074] The electromagnetic flowmeter 2 obtains the liquid-phase volume flow rate by collecting voltage signals, combines with the liquid thermal expansion coefficient and the density of the liquid at the reference temperature to calculate the corrected density of the liquid, and then accurately derives the liquid-phase mass flow rate, which can effectively eliminate the influence of temperature on the liquid density; the differential pressure flowmeter 5 collects the temperature and pressure of the fluid in the pipeline, calculates the gas density using the ideal gas law, and analyzes the gas-phase flow state in combination with the differential pressure signal characteristics, and finally realizes the accurate calculation of the total mass flow rate; the two complement each other's advantages: the electromagnetic flowmeter 2 has high stability for the measurement of the volume flow rate of conductive liquid phase, and the differential pressure flowmeter 5 adapts to the dynamic calculation of gas-phase density through the pressure-temperature coupling relationship, jointly covering the key links of liquid-phase mass flow rate correction and gas-phase density modeling in two-phase flow; this combined measurement method not only solves the problems of sensitivity to phase state changes and insufficient measurement accuracy of a single flowmeter in a multiphase flow environment, but also can comprehensively analyze the mass flow rate distribution and phase state characteristics of two-phase flow through the coupled calculation of corrected liquid density and gas density, providing high-precision and high-reliability flow data for fields such as chemical industry, petroleum, and energy, and helping with process optimization and safe operation under complex working conditions.

[0075] The methods for obtaining the total mass flow rate include:

[0076] Initialize the volume gas holdup. Based on the initialized volume gas holdup, calculate the average density by combining the gas density and the liquid corrected density. Calculate the initial total mass flow rate by combining the pressure difference collected by the differential pressure flowmeter 5, the liquid phase mass flow rate, the gas density, the structure coefficient, and the average density; If the gas density ; where is the pressure; is the molar mass of the gas; is the universal gas constant, specifically 8.314 J / (mol×K); The above formula is based on the ideal gas law. Through the pressure , the molar mass of the gas , the temperature , and the universal gas constant , accurately calculate the gas density, provide key gas phase parameters for subsequent average density modeling and total mass flow rate calculation, ensure the accuracy of gas phase physical property parameters, and improve the calculation accuracy of the gas phase contribution in two-phase flow; If the average density ; where is the initialized volume gas holdup; The above formula combines the initialized volume gas holdup with the gas and liquid phase densities to construct an average density model of the mixed medium, enabling the differential pressure flowmeter 5 to calculate the initial total mass flow rate based on the differential pressure signal, effectively integrating the two-phase physical property parameters, laying a foundation for measuring the total mass flow rate by the differential pressure method, and realizing the dynamic characterization of the density of the gas-liquid mixed phase; The initial total mass flow rate ; where is the structure coefficient; is the pressure difference; The above formula calculates the initial total mass flow rate using the structure coefficient, the pressure difference, and the average density, converts the differential pressure signal into a specific flow rate value, and combines the two-phase average density to initially quantify the total amount of the gas-liquid mixed flow, providing a starting point for subsequent iterative calculations and quickly establishing an initial estimation model of the total mass flow rate; The structure coefficient of the Venturi tube 3 can be calculated based on the inlet cross-sectional area and the throat cross-sectional area, such as ; where is the inlet cross-sectional area, is the inlet pipe diameter; is the throat cross-sectional area, is the throat pipe diameter; The above formula calculates the structure coefficient through the inlet cross-sectional area and the throat cross-sectional area of the Venturi tube 3, accurately reflecting the influence of the geometric characteristics of the Venturi tube 3 on flow measurement, ensuring that the differential pressure flowmeter 5 can accurately convert the pressure difference into flow parameters under different pipe diameter structures. The structure coefficient is a key correction factor for the structural characteristics of the device and directly affects the conversion accuracy between the differential pressure signal and the flow rate.

[0077] The difference between the initial total mass flow rate and the liquid-phase mass flow rate is calculated to obtain the gas mass flow rate. Based on the gas mass flow rate, the liquid-phase volume flow rate, the corrected liquid density, and the gas density, the updated volume gas holdup is calculated. The initial total mass flow rate is updated according to the updated volume gas holdup to obtain the updated total mass flow rate. The volume gas holdup and the total mass flow rate are repeatedly updated until the change difference of the total mass flow rate is less than the preset change threshold, and the last updated total mass flow rate is taken as the final total mass flow rate. As ; among them, is the updated volume gas holdup; is the liquid-phase volume flow rate; is the gas mass flow rate; The above formula updates the volume gas holdup through the relationship between the gas mass flow rate and the liquid-phase volume flow rate, dynamically adjusts the gas-phase proportion, and makes the volume gas holdup more conform to the actual two-phase flow state. Based on the liquid-phase volume flow rate measured by the electromagnetic flowmeter 2 and the gas mass flow rate, and combined with the gas-liquid density ratio to correct the volume gas holdup, it provides more accurate phase distribution parameters for the iterative correction of the total mass flow rate, and improves the accuracy of the gas-phase content characterization in the two-phase flow.

[0078] The average density is updated according to the updated volume gas holdup, and then the initial total mass flow rate is updated according to the updated average density to obtain the updated total mass flow rate; the updated volume gas holdup and the total mass flow rate The relationship between them can be expressed as: ; By continuously substituting the updated volume gas holdup into this formula, the total mass flow rate is repeatedly corrected until its change is less than the preset change threshold. By deeply integrating the differential pressure signal of the differential pressure flowmeter 5 and the liquid-phase flow data of the electromagnetic flowmeter 2, the initial assumption error is eliminated, and high-precision convergence of the total mass flow rate is achieved in the complex changes of the two-phase flow, ensuring that the measurement results conform to the actual working conditions. It is the core calculation link to realize the data collaborative optimization of the differential pressure flowmeter 5 and the electromagnetic flowmeter 2; Iterative update is carried out according to the relationship between the volume gas holdup and the total mass flow rate. When the change difference before and after the update of the total mass flow rate is less than the preset change threshold, the updated total mass flow rate is taken as the final total mass flow rate.

[0079] The electromagnetic flowmeter 2 directly collects the liquid phase volume flow rate and obtains the liquid corrected density in combination with temperature correction, providing basic parameters for the calculation of the liquid phase mass flow rate; the differential pressure flowmeter 5 uses the structural characteristics of the venturi tube 3 to collect the differential pressure signal, and constructs an average density model in combination with the initial volume gas content, gas density and liquid corrected density, and then obtains the initial total mass flow rate; on this basis, by establishing an iterative relationship between the volume gas content and the total mass flow rate, the volume gas content is continuously updated and the total mass flow rate is corrected until the difference in the total mass flow rate change is less than the preset change threshold, ensuring that the measurement result converges to the true value; this combined measurement method gives full play to the stable measurement advantage of the electromagnetic flowmeter 2 for the liquid phase volume flow rate and the sensitive capture ability of the differential pressure flowmeter 5 for the overall flow characteristics of the two-phase flow, eliminates the single-phase assumption error through the iterative algorithm, and effectively solves the interference problem of phase change in gas-liquid two-phase flow on density and flow type, significantly improving the accuracy and reliability of multiphase flow measurement. This solution has important application value in the fields of petrochemicals, energy extraction, process control, etc. It can provide real-time and accurate total mass flow data support for component analysis, process optimization and energy efficiency evaluation of gas-liquid two-phase flow, and facilitate efficient production and safety monitoring under complex working conditions.

[0080] The multi-sensor time series data is used as the input of the weight optimization model to obtain the optimized volume gas content and total mass flow rate; the multi-sensor time series data includes pressure difference, voltage, temperature and pressure; the multi-sensor time series data such as pressure difference, voltage, temperature and pressure are input into the Transformer weight optimization model, which can make full use of the model's ability to capture time series features, deeply explore the dynamic correlation and complex coupling relationship between various parameters, and then realize the intelligent optimization of volume gas content and total mass flow rate. This method effectively integrates the core measurement information of the differential pressure flowmeter 5 and the electromagnetic flowmeter 2, and at the same time combines the influence of temperature and pressure on gas-liquid density, dynamically adapts to the complex and changeable working conditions of two-phase flow, significantly improves the calculation accuracy and reliability of volume gas content and total mass flow rate, and provides more accurate and stable key parameters for two-phase flow analysis, which strongly supports the efficient monitoring, precise control and optimized operation of related industrial processes.

[0081] The training methods for weight optimization models include:

[0082] W groups of type identification data are collected in advance, and the type identification data include multi-sensor time series data, optimized volumetric gas fraction and total mass flow rate.

[0083] Taking the multi-sensor time-series data as the input of the weight optimization model, and taking the optimized volumetric gas holdup and total mass flow rate as the output of the weight optimization model, with the goal of minimizing the error between the optimized volumetric gas holdup and total mass flow rate output by the weight optimization model and the actual optimized volumetric gas holdup and total mass flow rate, optimizing the network parameters of the weight optimization model through a nature-inspired optimization algorithm, obtaining the network parameters corresponding to the minimum error between the optimized volumetric gas holdup and total mass flow rate output by the weight optimization model and the actual optimized volumetric gas holdup and total mass flow rate, and constructing the weight optimization model with the corresponding network parameters as the trained weight optimization model; among them, the weight optimization model is a Transformer model.

[0084] In the full-pipe single-phase flow (such as pure liquid or pure gas) state, it is judged whether the preset trigger condition is met. If it is met, the baseline parameters of the differential pressure flowmeter 5 and the electromagnetic flowmeter 2 are calibrated to obtain the zero-point drift corresponding to the differential pressure flowmeter 5 and the electromagnetic flowmeter 2, and the corresponding flowmeter parameters are updated according to the zero-point drift.

[0085] The method for judging whether the preset trigger condition is met includes:

[0086] Preset trigger conditions (such as pressure fluctuation less than 1% of the full scale, temperature fluctuation less than 0.5 °C / min, and signal noise of the electromagnetic flowmeter 2 lower than 0.2% of the full scale). When the trigger condition is met, the real-time flow calculation is paused, and the baseline parameters of the differential pressure flowmeter 5 and the electromagnetic flowmeter 2 are calibrated.

[0087] By setting strict thresholds for pressure fluctuation, temperature fluctuation, signal noise of the electromagnetic flowmeter 2, etc., triggering calibration under the stable working condition of full-pipe single-phase flow, avoiding external interference, ensuring that the calibration process is in an ideal state, providing a prerequisite for subsequent accurate calibration of flowmeter parameters, and improving the basic reliability and accuracy of two-phase flow analysis.

[0088] The method for calibrating the baseline parameters of the differential pressure flowmeter 5 includes:

[0089] In the state where the differential pressure flowmeter 5 has no flow, collect the zero-point drift output by the differential pressure flowmeter 5 N times, and calculate the average value of the zero-point drift output by the differential pressure flowmeter 5 N times as the zero-point drift of the differential pressure.

[0090] In the state of known flow, record the differential pressure of the differential pressure flowmeter 5, calculate the difference between the differential pressure and the zero-point drift of the differential pressure, and mark it as the actual differential pressure.

[0091] Establish a differential pressure-flow relationship regarding the structure coefficient, actual differential pressure, and known flow; such as ; among them, is the structure coefficient; is the known flow; is the actual differential pressure; is the fluid density in the differential pressure flowmeter 5; the corresponding structural coefficient value is calculated according to the differential pressure flow relationship, and the corresponding structural coefficient value is used as the flowmeter parameter corresponding to the differential pressure flowmeter 5.

[0092] When there is no flow, collect the zero drift amount and take the average to determine the zero drift of the differential pressure. When the flow is known, calculate the structural coefficient in combination with the actual differential pressure and the differential pressure flow relationship. This method eliminates the zero error of the differential pressure flowmeter 5, accurately determines the structural characteristic parameters, enables the differential pressure signal to be more accurately converted into a flow value, and improves the accuracy and reliability of the differential pressure flowmeter 5 in measuring the flow rate in two-phase flow (especially the gas-liquid mixed phase involving differential pressure changes).

[0093] The method for calibrating the baseline parameters of the electromagnetic flowmeter 2 includes:

[0094] In the state where the electromagnetic flowmeter 2 has no flow, collect the zero drift of the output voltage of the electromagnetic flowmeter 2 N times, and calculate the average value of the zero drift of the output voltage of the electromagnetic flowmeter 2 N times as the zero drift of the voltage;

[0095] In the state where the flow is known, record the voltage of the electromagnetic flowmeter 2, calculate the difference between the voltage and the zero drift of the voltage, and mark it as the actual voltage;

[0096] Establish a voltage-flow velocity relationship regarding the sensitivity coefficient of the electromagnetic flowmeter 2, the actual voltage, the pipe cross-sectional area, and the known flow rate; such as ; where is the known flow rate; is the sensitivity coefficient of the electromagnetic flowmeter 2, which can be obtained by optimizing through a nature-inspired optimization algorithm; is the actual voltage; is the pipe cross-sectional area; calculate the sensitivity coefficient of the electromagnetic flowmeter 2 according to the voltage-flow velocity relationship; use the sensitivity coefficient of the electromagnetic flowmeter 2 as the flowmeter parameter corresponding to the electromagnetic flowmeter 2.

[0097] Determine the voltage zero drift when there is no flow, and calculate the sensitivity coefficient through the voltage-flow velocity relationship when the flow is known. This process calibrates the zero deviation of the electromagnetic flowmeter 2, clarifies the conversion relationship between voltage and flow rate, ensures that its output voltage signal can accurately reflect the liquid phase volume flow rate, and lays a foundation for the accurate calculation of liquid phase parameters (such as volume flow rate, mass flow rate) in two-phase flow analysis.

[0098] The method for updating the corresponding flowmeter parameters according to the zero drift includes:

[0099] According to the temperature coefficients of the differential pressure flowmeter 5 and the electromagnetic flowmeter 2, combine with dynamic correction of the outputs of the differential pressure flowmeter 5 and the electromagnetic flowmeter 2. Such as ; ; where and are the temperature coefficients of the differential pressure flowmeter 5 and the electromagnetic flowmeter 2 respectively, which can be provided by the manufacturer or calibrated through experiments; is the actual pressure difference after dynamic correction; is the actual voltage after dynamic correction.

[0100] The above method can compensate for the influence of temperature on the output of the flowmeter, keep the differential pressure and voltage signals stable and accurate at different temperatures, adapt to complex working conditions, ensure the dynamic optimization of the flowmeter parameters with temperature in the two-phase flow analysis, and maintain the measurement accuracy and system adaptability.

[0101] Combined with the real-time temperature and real-time pressure, dynamically correct the zero drift corresponding to the differential pressure flowmeter 5 and the electromagnetic flowmeter 2, as well as the flowmeter parameters corresponding to the zero drift.

[0102] The method for dynamically correcting the zero drift corresponding to the differential pressure flowmeter 5 and the electromagnetic flowmeter 2 includes:

[0103] Update the zero drift of the differential pressure flowmeter 5 and the electromagnetic flowmeter 2 according to the zero drift of the differential pressure flowmeter 5 and the electromagnetic flowmeter 2 combined with the proportional gain and the real-time error, and obtain the updated zero drift of the differential pressure flowmeter 5 and the electromagnetic flowmeter 2.

[0104] Dynamically adjust the zero drift of the differential pressure flowmeter 5 and the electromagnetic flowmeter 2 through the real-time error and the proportional gain, which can timely correct the zero drift caused by working condition fluctuations or device aging, ensure the accuracy of the flowmeter output signal reference, provide a reliable original measurement starting point for the two-phase flow analysis, and avoid the influence of zero error accumulation on the subsequent flow calculation accuracy.

[0105] The method for dynamically correcting the flowmeter parameters corresponding to the zero drift includes:

[0106] Update the sensitivity coefficient of the electromagnetic flowmeter 2 according to the reference flow deviation and the flow deviation, and obtain the updated sensitivity coefficient of the electromagnetic flowmeter 2; adaptively optimize the sensitivity coefficient of the electromagnetic flowmeter 2 according to the flow deviation, which can make it better adapt to the real-time flow change, ensure the accuracy of the liquid-phase volume flow measurement, and then ensure the reliability of the liquid-phase mass flow and total mass flow calculations, and improve the dynamic adaptability of the electromagnetic flowmeter 2 to the liquid-phase parameter measurement in the two-phase flow.

[0107] Under the standard temperature, calibrate the initial temperature drift coefficient, collect the real-time temperature, calculate the difference between the real-time temperature and the standard temperature, and obtain the temperature change; by determining the initial temperature drift coefficient under the standard temperature and combining the difference between the real-time temperature and the standard temperature, establish the basis for quantifying the temperature change, provide basic data for compensating the influence of temperature on the flowmeter output, enable the differential pressure flowmeter 5 and the electromagnetic flowmeter 2 to adapt to the temperature fluctuation working conditions, and maintain the stability of the temperature-related parameters in the two-phase flow analysis.

[0108] Under preset working conditions, fix the flow rate and change the temperature, and record the pressure drift corresponding to the temperature change; explore the relationship between temperature and pressure drift under preset working conditions, clarify the specific influence law of temperature change on pressure parameters, provide a measured basis for the pressure signal correction of the differential pressure flowmeter 5 at different temperatures, and optimize the measurement accuracy of the differential pressure flowmeter 5 for pressure and flow parameters in a temperature-changing environment.

[0109] Calculate the temperature drift coefficient compensation value according to the temperature change amount and the pressure drift amount. As ; among them, is the temperature drift coefficient compensation value; is the temperature change amount; is the pressure drift amount; is the regularization coefficient, and an empirical value can be taken, which is mainly used to prevent the denominator from approaching zero.

[0110] Compensate the temperature coefficient according to the temperature drift coefficient compensation value; calculate the temperature drift coefficient compensation value by using the temperature change amount, the pressure drift amount and the regularization coefficient, dynamically adjust the temperature coefficient, effectively compensate the influence of temperature on the output characteristics of the flowmeter, reduce the measurement deviation caused by temperature drift, ensure the stability of the parameters of the differential pressure flowmeter 5 and the electromagnetic flowmeter 2 under variable temperature conditions, and improve the measurement accuracy and reliability of the two-phase flow analysis in the full working condition range.

[0111] Embodiment 2:

[0112] Please refer to Figure 6 shown. This embodiment provides a two-phase flow analysis system based on a differential pressure flowmeter and an electromagnetic flowmeter, including:

[0113] Device building module: Install a differential pressure flowmeter and an electromagnetic flowmeter at adjacent cross-sections of the pipeline;

[0114] First analysis module: Collect the voltage signal of the electromagnetic flowmeter, analyze and obtain the liquid-phase volume flow rate, combine the liquid thermal expansion coefficient and the density of the liquid at the reference temperature, calculate the corrected liquid density, and calculate the liquid-phase mass flow rate based on the corrected liquid density and the liquid-phase volume flow rate;

[0115] Second analysis module: Collect the temperature and pressure of the fluid in the pipeline, calculate the gas density according to the temperature and pressure using the ideal gas law, and calculate the total mass flow rate according to the gas density;

[0116] Third analysis module: Use the multi-sensor time-series data as the input of the weight optimization model to obtain the optimized gas volume fraction and total mass flow rate; the multi-sensor time-series data includes differential pressure, voltage, temperature and pressure;

[0117] Static calibration module: In the full-pipe single-phase flow state, it determines whether the preset trigger conditions are met. If so, it calibrates the baseline parameters of the differential pressure flowmeter and the electromagnetic flowmeter, obtains the zero drift corresponding to the differential pressure flowmeter and the electromagnetic flowmeter, and updates the corresponding flowmeter parameters according to the zero drift;

[0118] Feedback correction module: In combination with the real-time temperature and real-time pressure, it dynamically corrects the zero drift corresponding to the differential pressure flowmeter and the electromagnetic flowmeter, as well as the flowmeter parameters corresponding to the zero drift.

[0119] The system also realizes low-latency networking of multiple devices based on the RS485 protocol, can be compatible with cloud data storage and remote monitoring, and is suitable for industrial Internet of Things scenarios.

[0120] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

[0121] Finally: The above is only the preferred embodiment of the present invention and is not used to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A two-phase flow analysis method based on a differential pressure flowmeter and an electromagnetic flowmeter, characterized in that It includes the following steps: Install a differential pressure flowmeter and an electromagnetic flowmeter at adjacent cross-sections of the pipeline; Collect the voltage signal of the electromagnetic flowmeter, and calculate the liquid-phase mass flow by combining the liquid thermal expansion coefficient and the density of the liquid at the reference temperature; Collect the temperature and pressure of the fluid in the pipeline, calculate the gas density according to the temperature and pressure using the ideal gas law, and calculate the total mass flow according to the gas density; Use the multi-sensor time-series data as the input of the weight optimization model to obtain the optimized gas holdup and total mass flow; the multi-sensor time-series data includes differential pressure, voltage, temperature and pressure; Under the full-pipe single-phase flow state, determine whether it meets the preset trigger condition. If it meets, calibrate the baseline parameters of the differential pressure flowmeter and the electromagnetic flowmeter to obtain the zero-point drift corresponding to the differential pressure flowmeter and the electromagnetic flowmeter, and update the corresponding flowmeter parameters according to the zero-point drift; Combine the real-time temperature and real-time pressure to dynamically correct the zero-point drift corresponding to the differential pressure flowmeter and the electromagnetic flowmeter, and the flowmeter parameters corresponding to the zero-point drift.

2. The two-phase flow analysis method based on a differential pressure flowmeter and an electromagnetic flowmeter according to claim 1, characterized in that, The method for obtaining the liquid-phase mass flow includes: Collect the voltage signal of the electromagnetic flowmeter, analyze to obtain the liquid-phase volume flow, combine the liquid thermal expansion coefficient and the density of the liquid at the reference temperature to calculate the corrected liquid density, and calculate the product of the corrected liquid density and the liquid-phase volume flow to obtain the liquid-phase mass flow.

3. The two-phase flow analysis method based on a differential pressure flowmeter and an electromagnetic flowmeter according to claim 1, wherein The method for calculating the total mass flow includes: Initialize the gas holdup, calculate the average density according to the initialized gas holdup, combining the gas density and the corrected liquid density, and calculate the initial total mass flow by combining the differential pressure collected by the differential pressure flowmeter, the liquid-phase mass flow, the structure coefficient and the average density; Calculate the updated gas holdup according to the gas mass flow, liquid-phase volume flow, corrected liquid density and gas density, update the initial total mass flow according to the updated gas holdup to obtain the updated total mass flow, repeat updating the gas holdup and the total mass flow until the change difference of the total mass flow is less than the preset change threshold, and take the last updated total mass flow as the final total mass flow.

4. The two-phase flow analysis method based on a differential pressure flowmeter and an electromagnetic flowmeter according to claim 1, wherein The method for determining whether it meets the preset trigger condition includes: Preset the trigger condition. When the trigger condition is met, pause the real-time flow calculation and calibrate the baseline parameters of the differential pressure flowmeter and the electromagnetic flowmeter.

5. The two-phase flow analysis method based on a differential pressure flowmeter and an electromagnetic flowmeter according to claim 1, characterized in that The method for calibrating the baseline parameters of the differential pressure flowmeter includes: Under the state of no flow in the differential pressure flowmeter, collect the zero-point drift output by the differential pressure flowmeter N times, and calculate the average value of the zero-point drift output by the differential pressure flowmeter N times as the zero-point drift of the differential pressure; Under the known flow state, record the differential pressure of the differential pressure flowmeter, calculate the difference between the differential pressure and the zero-point drift of the differential pressure, and mark it as the actual differential pressure; Establish a differential pressure-flow relationship regarding the structure coefficient, actual differential pressure and known flow, calculate the value of the corresponding structure coefficient according to the differential pressure-flow relationship, and take the value of the corresponding structure coefficient as the flowmeter parameter corresponding to the differential pressure flowmeter.

6. The two-phase flow analysis method based on a differential pressure flowmeter and an electromagnetic flowmeter according to claim 1, wherein, The method for calibrating the baseline parameters of the electromagnetic flowmeter includes: Under the condition of no flow in the electromagnetic flowmeter, collect the zero drift of the output voltage of the electromagnetic flowmeter N times, and calculate the average value of the zero drift of the output voltage of the electromagnetic flowmeter N times as the zero drift of the voltage; Under the condition of known flow, record the voltage of the electromagnetic flowmeter, calculate the difference between the voltage and the zero drift of the voltage, and mark it as the actual voltage; Establish a voltage-flow velocity relationship regarding the sensitivity coefficient of the electromagnetic flowmeter, the actual voltage, the pipe cross-sectional area, and the known flow rate, and calculate the sensitivity coefficient of the electromagnetic flowmeter based on the voltage-flow velocity relationship; Take the sensitivity coefficient of the electromagnetic flowmeter as the flowmeter parameter corresponding to the electromagnetic flowmeter.

7. The two-phase flow analysis method based on a differential pressure flowmeter and an electromagnetic flowmeter according to claim 1, characterized in that, The method for updating the corresponding flowmeter parameters according to the zero drift includes: Based on the temperature coefficients of the differential pressure flowmeter and the electromagnetic flowmeter, dynamically correct the outputs of the differential pressure flowmeter and the electromagnetic flowmeter in combination.

8. The two-phase flow analysis method based on a differential pressure flowmeter and an electromagnetic flowmeter according to claim 1, wherein The method for dynamically correcting the zero drift corresponding to the differential pressure flowmeter and the electromagnetic flowmeter includes: Update the zero drift of the differential pressure flowmeter and the electromagnetic flowmeter according to the zero drift of the differential pressure flowmeter and the electromagnetic flowmeter in combination with the proportional gain and the real-time error, and obtain the updated zero drift of the differential pressure flowmeter and the electromagnetic flowmeter.

9. The two-phase flow analysis method based on a differential pressure flowmeter and an electromagnetic flowmeter according to claim 1, characterized in that The method for dynamically correcting the flowmeter parameters corresponding to the zero drift includes: Update the sensitivity coefficient of the electromagnetic flowmeter according to the reference flow deviation and the flow deviation, and obtain the updated sensitivity coefficient of the electromagnetic flowmeter; Under the standard temperature, calibrate the initial temperature drift coefficient, collect the real-time temperature, and calculate the difference between the real-time temperature and the standard temperature to obtain the temperature change; Under the preset working condition, fix the flow rate and change the temperature, and record the pressure drift corresponding to the temperature change; Calculate the temperature drift coefficient compensation value according to the temperature change and the pressure drift.

10. The two-phase flow analysis method based on a differential pressure flowmeter and an electromagnetic flowmeter according to claim 1, wherein The method for obtaining the liquid-phase volume flow rate includes: Collect the voltage signal of the electromagnetic flowmeter, calculate the product of the voltage signal and the pipe cross-sectional area, and obtain the liquid-phase volume flow rate.

11. A two-phase flow analysis system based on a differential pressure flowmeter and an electromagnetic flowmeter, implementing the two-phase flow analysis method based on a differential pressure flowmeter and an electromagnetic flowmeter according to any one of claims 1-10, characterized in that, Include: Device construction module: Install a differential pressure flowmeter and an electromagnetic flowmeter at adjacent cross-sections of the pipeline; First analysis module: Collect the voltage signal of the electromagnetic flowmeter, analyze and obtain the liquid-phase volume flow rate, combine the liquid thermal expansion coefficient and the density of the liquid at the reference temperature, calculate the corrected liquid density, and calculate the liquid-phase mass flow rate based on the corrected liquid density and the liquid-phase volume flow rate; Second analysis module: Collect the temperature and pressure of the fluid in the pipeline, and calculate the gas density according to the temperature and pressure using the ideal gas law, and calculate the total mass flow rate according to the gas density; Third analysis module: Take the multi-sensor time-series data as the input of the weight optimization model to obtain the optimized volume gas holdup and the total mass flow rate; The multi-sensor time-series data includes differential pressure, voltage, temperature, and pressure; Static calibration module: Under the condition of full-pipe single-phase flow, judge whether it meets the preset trigger condition. If it meets, calibrate the baseline parameters of the differential pressure flowmeter and the electromagnetic flowmeter to obtain the zero drift corresponding to the differential pressure flowmeter and the electromagnetic flowmeter, and update the corresponding flowmeter parameters according to the zero drift; Feedback correction module: Combining the real-time temperature and real-time pressure, dynamically correct the zero drift corresponding to the differential pressure flowmeter and the electromagnetic flowmeter, as well as the flowmeter parameters corresponding to the zero drift.

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