A vortex-perturbation wave dual-mode wet gas measurement method based on Newton iteration

Abstract

The application provides a vortex-perturbation wave double-mode wet gas measuring method based on Newton iteration, which comprises establishing a gas-liquid phase flow measuring model and vortex wet gas phase flow measurement; when the vortex wet gas phase flow measurement is performed, pressure, temperature, liquid film thickness fluctuation signal and vortex signal are collected first; gas density, liquid density and liquid phase surface tension are calculated through the pressure and the temperature respectively, vortex frequency is extracted, and perturbation wave height is extracted; then, two-phase vortex flow indicator value is calculated and taken as an initial value of Newton iteration format; iteration solving is performed, and whether the iteration termination condition is met is judged; gas phase apparent flow velocity and gas phase Weber number are solved; finally, liquid phase Reynolds number is calculated, and then actual liquid phase flow is calculated. The application utilizes the perturbation wave height information of the liquid film to correct and compensate over-reading OR of the vortex measurement, the vortex over-reading is related to the gas phase Weber number and the liquid phase Reynolds number, the gas phase flow and the liquid phase flow are obtained, and the measuring method is simple and economical.

Description

Technical Field

[0001] This invention belongs to the field of moisture phase flow measurement technology, and in particular relates to a dual-mode moisture measurement method based on Newton's iteration vortex street-disturbance wave. Background Technology

[0002] Moist two-phase flow is extremely common in industrial processes, such as condensed natural gas containing a small amount of liquid, and wet steam injected into oil wells during heavy oil thermal recovery. Generally speaking, moist two-phase flow refers to gas-liquid two-phase flow with a gas phase volume content exceeding 95% or a Lockhart parameter below 0.3. Annular mist flow, as a widely existing fluid form, plays a crucial role in many industrial scenarios. Accurate measurement of moist two-phase flow is essential for energy extraction, safe production, transportation and trade, and energy conservation. In heavy oil thermal recovery operations, the accuracy of steam measurement and control directly impacts oil production and efficiency. Given the high viscosity and specific gravity of heavy oil, over 80% of current extraction technologies employ thermal extraction methods, which involve injecting high-temperature, high-pressure wet saturated steam into oil wells, utilizing the latent heat of vaporization to heat the reservoir. The dryness and flow rate of the injected steam play a key role in the economics of heavy oil thermal recovery. Therefore, accurate measurement of steam dryness and flow rate is a prerequisite for effective control and a crucial technical guarantee for improving the economics of heavy oil thermal recovery. During the flow of moist gas, the measurement of liquid phase flow rate is of paramount importance. Currently, commonly used methods such as X-ray diffraction, microwave diffraction, and isokinetic sampling methods face significant challenges in online measurement due to limitations in application scenarios and operational procedures, and also significantly increase measurement costs. There is an urgent need for an online measurement method with higher accuracy and ease of implementation. Summary of the Invention

[0003] In view of this, the present invention aims to overcome the defects in the prior art and proposes a dual-mode moisture measurement method based on Newton's iteration vortex street-disturbance wave.

[0004] To achieve the above objectives, the technical solution created by this invention is implemented as follows: A dual-mode moisture measurement method based on Newton's iteration vortex shelving and perturbation wave includes the following steps: S1. Establish a gas-liquid phase flow measurement model; S2. Using a vortex flow meter and a liquid film thickness sensor, the vortex flow rate of the wet gas phase separation is measured. The measurement method is as follows: 1) Acquire pressure, temperature, liquid film thickness fluctuation signals, and vortex street signals; 2) Calculate the gas density, liquid density, and liquid surface tension using pressure and temperature respectively. ， Extract the vortex shedding frequency and the disturbance wave height; 3) Calculate the reading of the two-phase vortex flowmeter and use it as the initial value for the Newton-Raphson iteration scheme; 4) Perform iterative solutions and determine whether the iteration termination condition is met. And the number of iterations has reached the upper limit. Q g，n This represents the gas phase flow rate obtained in this iteration. Q g，n-1 This represents the gas phase flow rate obtained in the previous iteration. If the iteration termination condition is met, the iteration ends, and the gas phase flow rate is taken as the result of the last iteration. Q g ; 5) Calculate the apparent gas velocity and the gas Weber number; 6) Calculate the liquid phase Reynolds number, and then calculate the actual liquid phase flow rate.

[0005] Furthermore, the method for establishing a gas-liquid phase flow measurement model is as follows: In two-phase flow, the reading of the vortex flow meter Q g,apparent Compared to actual gas phase flow rate Q g The ratio is too high, and the ratio of the two is the overreading coefficient OR, as shown in formula (1): (1) Calculate the reading of the two-phase vortex flowmeter using formula (2). Q g,apparent (2) Among them, the gas phase Weber number We g and liquid phase Reynolds number Re l As parameters, establish the overreading coefficient OR and the disturbance wave height. h DW The correlations are shown in formulas (3) and (4). (3) (4) in, k 1 and k 2 is a constant coefficient; n 1, n 2, n 3 and n 4 represents a constant power exponent; gas phase Weber number We g From the formula The calculated apparent gas flow rate was obtained. U sg From the formula Calculations show thatD The diameter of the pipe; By combining equations (3) and (4), a gas phase flow rate can be established. Q g Equations with unknowns f ( Q g As shown in formula (5) (5) in, , , , Pipe cross-sectional area ; The Newton-Raphson iterative scheme is constructed to solve equation (5), as shown in equation (6). (6) The gas phase flow rate can be obtained by solving the problem using the iterative method in formula (6). Q g Thus, the apparent flow rate of the gas phase is obtained. U sg Harmony and Weber numbers We g Formula (7) is derived from formula (4) to calculate the liquid phase Reynolds number. Re l The actual liquid flow rate is calculated according to equation (8). Q l (7) (8) in, This represents the dynamic viscosity of the liquid.

[0006] Furthermore, the FFT algorithm is used to extract the vortex shedding frequency. f v .

[0007] Furthermore, through p and T Calculate the gas density under the corresponding operating conditions. Liquid density Timing signals for vortex flow meters s ( t Perform a Fast Fourier Transform to extract the frequency of the vortex shedding signal. f VS .

[0008] Furthermore, by fitting the experimental data using the least squares method, the height of the disturbance wave shown was obtained. h DW With the phase of the Weber number Weg and liquid phase Reynolds number Re l Relationship between them: ;in, D This refers to the pipe diameter.

[0009] Furthermore, by fitting the experimental data using the least squares method, the vortex overreading coefficient OR and the gas phase Weber number were obtained. We g and liquid phase Reynolds number Re l Relationship between them: .

[0010] Furthermore, by measuring the vortex shedding frequency f VS The volumetric flow rate can then be obtained: ;in, K v The instrument coefficient (m) of the vortex flow meter in single-phase gas -3 ).

[0011] Compared with existing technologies, the present invention has the following advantages: This invention utilizes the disturbance wave height information of the liquid film to correct and compensate for the overreading error (OR) of vortex street measurements, and establishes a correlation between vortex street overreading and the gas phase Weber number and liquid phase Reynolds number, finally obtaining the gas phase flow rate and liquid phase flow rate. This invention eliminates the need for other complex and expensive gas and liquid phase measurement devices and methods; the measurement method is simple, economical, and provides high prediction accuracy. Attached Figure Description

[0012] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A schematic diagram of the structural arrangement of the measuring device is provided for this invention; Figure 2 This is a flowchart of the signal acquisition process; Figure 3 For the height of the disturbance wave h DW Compared with gas phase Weber number and liquid phase Reynolds number Re l Modeling a relationship diagram; Figure 4 Overread coefficient OR Compared with gas phase Weber number and liquid phase Reynolds number Re l Modeling a relationship diagram; Figure 5 For the phase of Weber number We gGas phase flow rate Q g Relationship diagram; Figure 6 For liquid phase Reynolds number Re l With liquid phase flow rate Q l Relationship diagram.

[0013] Explanation of reference numerals in the attached figures: 1-Annular electrode; 2-Pressure sensor; 3-Vortex flow meter; 4-Temperature sensor. Detailed Implementation

[0014] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0015] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0016] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0017] The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0018] A method for online measurement of phase-separated flow rates (gas phase flow rate and liquid phase flow rate) in a wet two-phase flow system based on a vortex shear-conductivity liquid film sensor dual-mode measurement system. Figures 1 to 6As shown, it uses the gas phase Weber number and liquid phase Reynolds number as parameters to affect the vortex overreading factor OR and the disturbance wave height of the liquid film, respectively. h DW Modeling is performed, and OR and h DW After simulating the equations, the derivation is based on the gas phase flow rate. Q g The equations with variables are solved using Newton's iteration method to obtain the gas phase flow rate and liquid phase flow rate. This includes the following steps: The first part establishes a gas-liquid phase flow measurement model, using the following method: In two-phase flow, the reading of the vortex flow meter Q g,apparent Compared to actual gas phase flow rate Q g The value is too high, and the ratio of the two is the overreading coefficient OR, as shown in formula (1). (1) Calculate the reading of the two-phase vortex flowmeter using formula (2). Q g,apparent (2) Among them, the gas phase Weber number We g and liquid phase Reynolds number Re l As parameters, establish the overreading coefficient OR and the disturbance wave height. h DW The correlations are shown in formulas (3) and (4). (3) (4) in k 1 and k 2 is a constant coefficient; n 1, n 2, n 3 and n 4 represents a constant power exponent; gas phase Weber number We g From the formula The calculated apparent gas flow rate was obtained. U sg From the formula Calculations show that D This refers to the pipe diameter.

[0019] By combining formulas (3) and (4), a gas phase flow rate can be established. Q g Equations with unknowns f ( Q gAs shown in formula (5) (5) in , , , Among them, the cross-sectional area of ​​the pipe .

[0020] The Newton-Raphson iterative scheme is constructed to solve equation (5), as shown in equation (6). (6) The gas phase flow rate can be obtained by solving the problem using the iterative method in formula (6). Q g Thus, the apparent flow rate of the gas phase is obtained. U sg Harmony and Weiber Numbers We g Formula (7) is derived from formula (4) to calculate the liquid phase Reynolds number. Re l The actual liquid flow rate is calculated according to equation (8). Q l (7) (8) in, This represents the dynamic viscosity of the liquid.

[0021] The second part describes the measurement of vortex-driven wet gas phase flow using a vortex flow meter and a liquid film thickness sensor, as follows: 1) Acquisition pressure p ,temperature T Liquid film thickness fluctuation signal δ ( t ) and vortex street signal s ( t ); 2) Through pressure p and temperature T Calculate the gas density separately Liquid density and liquid phase surface tension ， Extracting vortex shedding frequency using the FFT algorithm f vs And extract the height of the disturbance wave. h DW ; 3) Calculate the reading of the two-phase vortex flowmeter using formula (2). Q g,apparent And use it as the initial value of the Newton iteration scheme; 4) Solve iteratively according to Newton's iterative scheme formula (6) and determine whether the iteration termination condition is met. And the number of iterations has reached the upper limit. Q g，n This represents the gas phase flow rate obtained in this iteration. Q g，n-1 This represents the gas phase flow rate obtained in the previous iteration. If the iteration termination condition is met, the iteration ends, and the result of the last iteration is considered to be the gas phase flow rate. Q g ; 5) Calculate the apparent gas velocity. U sg Harmony and Weiber Numbers We g ; 6) Calculate the liquid phase Reynolds number using formula (7) Re l， Calculate the actual liquid flow rate according to equation (8). Q l .

[0022] in, This represents the dynamic viscosity of the liquid.

[0023] Based on the above method, the measurement of wet gas phase separation flow rate in vortex flow was finally achieved. Furthermore, this method has the following advantages: (1) It can realize the measurement of moisture phase flow rate.

[0024] This method establishes the relationship between the overreading coefficient OR and the disturbance wave height. h DW The correlation between these factors is used to compensate for overreading in uncorrected gas phase flow rates, thus enabling gas phase flow rate measurement. Furthermore, an overreading coefficient (OR) and the gas phase Weber number are established. We g and liquid phase Reynolds number Re l The model between the two phases is used to solve for the liquid phase flow rate, and finally the wet gas phase flow rate measurement is realized.

[0025] (2) Simple, low cost, online measurement.

[0026] Moisture phase flow rate can be measured by using a vortex flow meter, liquid film thickness sensor, pressure sensor, and temperature sensor to measure relevant parameters. This method is simple to operate, low in cost, and can be performed online.

[0027] (3) High prediction accuracy.

[0028] The method was used to predict gas and liquid flow rates under humid conditions. In the example, the relative error for gas volumetric flow rate prediction was within ±1%, and the relative error for liquid volumetric flow rate prediction was within ±15%.

[0029] This example demonstrates a vortex-driven method for measuring the phase flow rate of moist gas based on liquid film thickness modeling. The specific implementation in the moist gas measurement is described below. Using the multi-parameter adjustable mist flow experimental system described in patent 201810644726.7, the moist gas pressure was adjusted to 150 kPa ~ 350 kPa, and the gas phase flow rate was 12 m³ / s. 3 / h ~ 24 m 3 / h, liquid flow rate 0.55 mL / s ~ 4.5 mL / s, pipe diameter is constant. D =15 mm, the surface tension of the liquid is constant. σ= 0.072 N / m. A schematic diagram of the overall measuring device is attached. Figure 1 As shown.

[0030] By using two annular electrodes 1 arranged on the inner side of the tube wall, the liquid film thickness fluctuation signal is obtained by utilizing the electrical conductivity characteristics of the liquid film. δ ( t The signal acquisition flowchart is attached. Figure 2 As shown. Sensor signals are acquired, including the operating pressure output by the pressure sensor. p Operating temperature output by the temperature sensor T The vortex timing sequence number output by the vortex flow meter s ( t And the liquid film thickness fluctuation signal output by the liquid film thickness sensor in patent CN201910134650.8 δ ( t ).in s ( t The sampling frequency is 100 kHz, and the sampling time for each group of data is 10 s. δ ( t The sampling frequency is 32 MHz. Under the excitation of a sinusoidal signal (500 kHz), it samples 64 times in each cycle. After 8 cycles of sampling, the data is processed by the host computer.

[0031] Then, through p and T Calculate the gas density under the corresponding operating conditions. ρ g and liquid density ρ l Timing signals for vortex flow meters s ( t Perform a Fast Fourier Transform to extract the frequency of the vortex shedding signal. f VS .

[0032] A vortex flow meter is a velocity flow meter that measures the frequency of vortex shedding. fVS Volumetric flow rate can then be obtained. ;in K v The instrument coefficient (m) of the vortex flow meter in single-phase gas -3 ).

[0033] In moist gas flow, the presence of a small amount of liquid phase makes the measured gas volumetric flow rate different when using a vortex flowmeter to measure moist gas. Q g,apparent Flow rate higher than that of actual gas Q g This is known as the "overreading" phenomenon. Therefore, the reading of the vortex flowmeter... Q g,apparent Compared with actual traffic Q g The relationship between them is In the formula, OR is called the vortex street overreading coefficient.

[0034] To improve the measurement accuracy of vortex flowmeters, an OR prediction model needs to be established to correct the flowmeter readings. Past studies often used droplet parameters to build OR prediction models, but these parameters are often difficult to measure directly. Liquid film parameters can also characterize the internal flow characteristics of fluids, and they are easier to obtain. Next, based on the average liquid film thickness... δ A vortex overreading coefficient OR prediction model was established, and an average liquid film thickness was also established. δ Predictive models.

[0035] The disturbance wave height was obtained by fitting the experimental data using the least squares method. h DW With the phase of the Weber number We g and liquid phase Reynolds number Re l Relationship between them: in, D This refers to the pipe diameter.

[0036] Under the experimental conditions, the vortex overreading coefficient OR and the gas phase Weber number were obtained by fitting the experimental data using the least squares method. We g and liquid phase Reynolds number Re l Relationship between them: In this example, the vortex flow wet gas phase separation flow measurement was finally achieved using the above method.

[0037] To verify the wet gas phase flow measurement method combining a liquid film thickness sensor and a vortex flow meter proposed in the above scheme, the liquid film thickness can typically be used to predict the gas phase volumetric flow rate. The relative error of the gas phase volumetric flow rate prediction is within ±1%, where the relative error = (predicted value - actual value) / actual value × 100. The relative error of the liquid phase flow rate prediction under different operating conditions is within ±15%.

[0038] This invention utilizes the disturbance wave height information of the liquid film to correct and compensate for the overreading error (OR) of vortex street measurements, and establishes a correlation between vortex street overreading and the gas phase Weber number and liquid phase Reynolds number, finally obtaining the gas phase flow rate and liquid phase flow rate. This invention eliminates the need for other complex and expensive gas and liquid phase measurement devices and methods; the measurement method is simple, economical, and provides high prediction accuracy.

[0039] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dual-mode moisture measurement method based on Newton's iteration vortex street and perturbation wave, characterized in that, Includes the following steps: S1. Establish a gas-liquid phase flow measurement model; S2. Perform vortex-street wet gas phase flow rate measurement. The measurement method is as follows: 1) Collect pressure, temperature, liquid film thickness fluctuation signals, and vortex street signals; 2) Calculate the gas density using pressure and temperature respectively. Liquid density and liquid phase surface tension ， Extracting vortex frequency f vs And extract the height of the disturbance wave. h DW ; 3) Calculate the reading of the two-phase vortex flowmeter and use it as the initial value for the Newton iteration scheme; 4) Perform iterative solutions and determine whether the iteration termination condition is met. And the number of iterations has reached the upper limit. Q g，n This represents the gas phase flow rate obtained in this iteration. Q g，n-1 This represents the gas phase flow rate obtained in the previous iteration. If the iteration termination condition is met, the iteration ends, and the gas phase flow rate is taken as the result of the last iteration. Q g ; 5) Calculate the apparent gas velocity and the gas Weber number; 6) Calculate the liquid phase Reynolds number, and then calculate the actual liquid phase flow rate; The method for establishing the gas-liquid phase flow measurement model is as follows: In two-phase flow, the reading of the vortex flow meter Q g,apparent Compared to actual gas phase flow rate Q g The ratio is too high, and the ratio of the two is the overreading coefficient OR, as shown in formula (1): (1) Calculate the reading of the two-phase vortex flowmeter using formula (2). Q g,apparent (2) in, K v The instrument coefficient of the vortex flowmeter in single-phase gas is expressed as the gas phase Weber number. We g and liquid phase Reynolds number Re l As parameters, establish the overreading coefficient OR and the disturbance wave height. h DW The correlations are shown in formulas (3) and (4). (3) (4) in, k 1 and k 2 is a constant coefficient; n 1, n 2, n 3 and n 4 represents a constant power exponent; gas phase Weber number We g From the formula The calculation yielded that, For gas density, For liquid density and For liquid phase surface tension; for gas phase apparent flow rate U sg From the formula The calculation yielded that, D The diameter of the pipe; By combining equations (3) and (4), a gas phase flow rate can be established. Q g Equations with unknowns f ( Q g As shown in formula (5) (5) in, , , , Pipe cross-sectional area ; The Newton-Raphson iterative scheme is constructed to solve equation (5), as shown in equation (6). (6) The gas phase flow rate can be obtained by solving the problem using the iterative method in formula (6). Q g Thus, the apparent flow rate of the gas phase is obtained. U sg Harmony and Weber numbers We g Formula (7) is derived from formula (4) to calculate the liquid phase Reynolds number. Re l The actual liquid flow rate is calculated according to equation (8). Q l (7) (8) in, This represents the dynamic viscosity of the liquid.

2. The dual-mode moisture measurement method based on Newton's iteration and vortex shedding / disturbance wave as described in claim 1, characterized in that: Extracting vortex shedding frequency using the FFT algorithm f VS .

3. The dual-mode moisture measurement method based on Newton's iteration and vortex shedding / disturbance wave as described in claim 1, characterized in that: pass p and T Calculate the gas density under the corresponding operating conditions. ρ g and liquid density ρ l Timing signals for vortex flow meters s ( t Perform a Fast Fourier Transform to extract the frequency of the vortex shedding signal. f VS .

4. The dual-mode moisture measurement method based on Newton's iteration and vortex shedding / disturbance wave according to claim 1, characterized in that: By measuring the vortex shedding frequency f VS Calculate the volumetric flow rate: ;in, K v This is the instrument coefficient of the vortex flowmeter in single-phase gas.

Images