Moisture phase separation flow measurement method based on disturbance wave height and vortex flowmeter

Abstract

The application provides a wet gas phase separation flow measurement method based on disturbance wave height and vortex flow meter, first, pressure, temperature, liquid film thickness fluctuation signal and vortex signal are collected, then gas density, liquid density and liquid phase surface tension are calculated through pressure and temperature respectively, vortex frequency is extracted, and disturbance wave height parameter is extracted, then vortex flow meter gas phase flow is calculated, vortex two-phase over-reading coefficient is calculated, actual gas phase flow is calculated, gas phase apparent flow velocity is calculated, gas phase Weber number is calculated, liquid phase Reynolds number is calculated, and finally actual liquid phase flow is calculated. The application utilizes liquid film disturbance wave height information to correct and compensate over-reading OR of vortex measurement, and establishes a correlation formula of vortex over-reading, gas phase Weber number and liquid phase Reynolds number, and finally obtains gas phase flow and liquid phase flow. The application does not need other complex and expensive gas and liquid phase measurement devices and methods, can measure on line, and has simple, economical and high prediction precision measurement method.

Description

Technical Field

[0001] This invention belongs to the field of moisture phase flow measurement technology, and in particular relates to a method for measuring moisture phase flow based on disturbance wave height and vortex flow meter. 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. Globally, heavy oil resources are quite abundant, with proven reserves between 400 and 600 billion tons, accounting for more than 60% of the world's total oil resources. my country is the world's fourth-largest producer of heavy oil, after the United States, Canada, and Venezuela, with proven and controlled reserves of 16 billion tons. Domestic heavy oil production accounts for approximately 10% of total crude oil production annually. Therefore, significantly improving heavy oil extraction efficiency is of great significance to my country's economic development and energy conservation. Given the high viscosity and specific gravity of heavy oil, over 80% of current extraction technologies utilize 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 crucial role in the economics of thermal heavy oil extraction. Accurate measurement of wet steam not only avoids false boiler output data and improves steam quality but also reduces the amount of saturated water drained from steam pipelines, achieving energy savings. Measuring the liquid phase flow rate during the wet gas flow process is of paramount importance. Currently, commonly used methods such as X-ray methods, microwave methods, and isokinetic sampling methods face significant challenges in online measurement due to the characteristics of the application scenarios and limitations in operation, and also significantly increase measurement costs. There is an urgent need for an online measurement method that offers higher accuracy and is easy to implement. Summary of the Invention

[0003] In view of this, the present invention aims to overcome the deficiencies in the prior art and proposes a method for measuring the phase flow of wet gas based on disturbance wave height and vortex flow meter.

[0004] To achieve the above objectives, the technical solution created by this invention is implemented as follows: The method for measuring the phase flow rate of wet gas based on disturbance wave height and vortex flow meter includes the following steps: S1, Acquisition Pressure p,temperature T Liquid film thickness fluctuation signal d ( t ) and vortex street signal s ( t ); S2, through pressure p and temperature T Calculate the gas density separately Liquid density and liquid phase surface tension ， Extracting vortex frequency f vs And extract the disturbance wave height parameter. h DW ; S3. Calculate the apparent value of the gas phase flow meter of the vortex flow meter. Q g,apparent (1) in, K v For instrument coefficients; S4. Calculate the two-phase overreading coefficient OR of the vortex street. (2) in, k 1 is a constant coefficient; S5. Calculate the actual gas phase flow rate. Q g (3) S6. Calculate the apparent gas velocity. U sg (4) S7. Calculate the gas phase Weber number. We g (5) in, s The surface tension of the liquid; S8. Calculate the Reynolds number in the liquid phase. Re l (6) in, k 2 is a constant coefficient. n 2 and n 3 is a constant power exponent, and its specific value is obtained by fitting the function form described in formula (7). (7) Among them, the liquid phase Reynolds number , U sl The apparent flow rate of the liquid phase is... The dynamic viscosity of the liquid.

[0005] S9. Calculate the actual liquid flow rate. Q l (8) in, The dynamic viscosity of the liquid.

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

[0007] Furthermore, the least squares method is used to determine the height of the disturbance wave. h DW By fitting the OR to establish the relationship between the vortex street overreading coefficient OR and the disturbance wave height, a correlation is established. h DW The relationship is: ;in, D This refers to the pipe diameter.

[0008] 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: .

[0009] Furthermore, the gas phase volumetric flow rate is predicted using the liquid film thickness. The relative error of the gas phase volumetric flow rate prediction is within ±2%, where the relative error = (predicted value - actual value) / actual value × 100.

[0010] Furthermore, the prediction of liquid phase flow rate under different operating conditions has a relative error controlled within ±15%.

[0011] Compared with existing technologies, the present invention has the following advantages: This invention provides a method for measuring the phase flow rate of wet gas based on disturbance wave height and vortex flowmeter. It utilizes the disturbance wave height information of the liquid film to correct and compensate for the overreading error (OR) of vortex flowmeter measurements, and establishes a correlation between vortex overreading and the Weber number of the gas phase and the Reynolds number of the liquid phase. Finally, it obtains the gas phase flow rate and the liquid phase flow rate. This invention eliminates the need for other complex and expensive gas and liquid phase measurement devices and methods, enables online measurement, and 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 layout of the measuring device for this invention. Figure 2 Signal acquisition flowchart Figure 3 OR is the overreading coefficient and the disturbance wave height. h dw Modeling Relationship Diagram Figure 4 The overreading factor OR is related to the gas phase Weber number and the liquid phase Reynolds number. Re l Modeling Relationship Diagram Figure 5 For the phase of Weber number We g Gas 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] This invention uses a liquid film thickness sensor and a vortex flowmeter to measure the average liquid film thickness and the uncorrected gas phase flow rate, respectively. The average liquid film thickness under different inlet conditions is extracted, and a correlation between the overreading coefficient and the average liquid film thickness is established to address the vortex overreading problem. Gas phase flow rate measurement is achieved by compensating for the overreading of the uncorrected gas phase flow rate. To solve for the liquid phase flow rate, a model is further established between the average liquid film thickness and the Weber number of the gas and liquid phases, ultimately realizing the measurement of phase-separated flow rates under humid conditions. Figure 1 to Figure 6 As shown, the specific solution method is as follows: S1, Acquisition Pressure p ,temperature T Liquid film thickness fluctuation signal d ( t ) and vortex street signal s ( t ); S2, 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 disturbance wave height parameter. h DW ; S3. Calculate the apparent value of the gas phase flow of the vortex flow meter using equation (1). Q g,apparent (1) in, K v For instrument coefficients; S4. Calculate the two-phase overreading coefficient OR of the vortex street according to equation (2). (2) in,k 1 is a constant coefficient; S5. Calculate the actual gas phase flow rate according to equation (3). Q g (3) S6. Calculate the apparent velocity of the gas phase using equation (4). U sg (4) S7. Calculate the gas phase Weber number according to equation (5). We g (5) in, s The surface tension of the liquid; S8. Calculate the liquid phase Reynolds number using formula (6). Re l (6) in, k 2 is a constant coefficient. n 2 and n 3 is a constant power exponent, and its specific value is obtained by fitting the function form described in formula (7). (7) Among them, the liquid phase Reynolds number , U sl The apparent flow rate of the liquid phase is... The dynamic viscosity of the liquid.

[0019] S9. Calculate the actual liquid flow rate according to equation (8). Q l (8) in, The dynamic viscosity of the liquid.

[0020] Based on the above method, the measurement of vortex flow moisture phase flow was finally realized.

[0021] 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, it consists of an annular electrode 1, a pressure sensor 2, a vortex flow meter 3, and a temperature sensor 4.

[0022] 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. d ( 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 d ( t ).in s ( t The sampling frequency is 100 kHz, and the sampling time for each data set is 10 s. d ( 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.

[0023] Then, through p and T Calculate the gas density under the corresponding operating conditions. r g and liquid density r 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 .

[0024] A vortex flow meter is a velocity flow meter that measures the frequency of vortex shedding. f VS Volumetric flow rate can then be obtained. ;in, K v The instrument coefficient (m) of the vortex flow meter in single-phase gas -3 ).

[0025] 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.

[0026] 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... d A vortex overreading coefficient OR prediction model was established, and an average liquid film thickness was also established. d Predictive models.

[0027] Using the least squares method to determine the height of the disturbance wave h DW By fitting the OR to establish the relationship between the vortex street overreading coefficient OR and the disturbance wave height, a correlation is established. h DW The relationship is in, D This refers to the pipe diameter.

[0028] 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: Based on the above modeling and calibration results, the following is the implementation process for measuring the moisture phase flow rate, as shown in the following steps: 1) Acquisition pressure p ,temperature T Liquid film thickness fluctuation signal d ( 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 disturbance wave height parameter. h DW ; 3) Calculate the apparent value of the gas phase flow rate of the vortex flow meter using equation (1). Q g,apparent (1) in, K v For instrument coefficients; 4) Calculate the two-phase overreading coefficient OR of the vortex street according to equation (2). (2) in, k 1 is a constant coefficient; 5) Calculate the actual gas phase flow rate according to equation (3). Q g (3) 6) Calculate the apparent gas velocity using equation (4). U sg (4) 7) Calculate the gas phase Weber number according to equation (5). We g (5) in, s The surface tension of the liquid; 8) Calculate the liquid phase Reynolds number using formula (6). Re l (6) in, k 2 is a constant coefficient. n 2 and n 3 is a constant power exponent, and its specific value is obtained by fitting the function form described in formula (7). (7) Among them, the liquid phase Reynolds number , U sl The apparent flow rate of the liquid phase is... The dynamic viscosity of the liquid.

[0029] 9) Calculate the actual liquid flow rate according to equation (8). Ql (8) in, The dynamic viscosity of the liquid.

[0030] In this example, the vortex flow wet gas phase separation flow measurement was finally achieved using the above method.

[0031] To verify the wet gas phase flow measurement method combining the liquid film thickness sensor and vortex flow meter, the liquid film thickness can be used to predict the gas phase volumetric flow rate. The relative error of the gas phase volumetric flow rate prediction is within ±2%, 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%.

[0032] This invention provides a method for measuring the phase flow rate of wet gas based on disturbance wave height and vortex flowmeter. It utilizes the disturbance wave height information of the liquid film to correct and compensate for the overreading error (OR) of vortex flowmeter measurements, and establishes a correlation between vortex overreading and the Weber number of the gas phase and the Reynolds number of the liquid phase. Finally, it obtains the gas phase flow rate and the liquid phase flow rate. This invention eliminates the need for other complex and expensive gas and liquid phase measurement devices and methods, enables online measurement, and is simple, economical, and provides high prediction accuracy.

[0033] 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 method for measuring the phase flow rate of moist gas based on disturbance wave height and vortex flow meter, characterized in that, Includes the following steps: S1, Acquisition Pressure p ,temperature T Liquid film thickness fluctuation signal δ ( t ) and vortex street signal s ( t ); S2, through pressure p and temperature T Calculate the gas density separately Liquid density and liquid phase surface tension ， Extracting vortex frequency f vs And extract the disturbance wave height parameter. h DW ; S3. Calculate the apparent value of the gas phase flow meter of the vortex flow meter. Q g,apparent (1) in, K v For instrument coefficients; S4. Calculate the two-phase overreading coefficient OR of the vortex street. (2) in, k 1 is a constant coefficient. D The diameter of the pipe; S5. Calculate the actual gas phase flow rate. Q g (3) S6. Calculate the apparent gas phase velocity. U sg (4) S7. Calculate the gas phase Weber number. We g (5) in, σ The surface tension of the liquid; S8. Calculate the Reynolds number in the liquid phase. Re l (6) in, k 2 is a constant coefficient. n 2 and n 3 is a constant power exponent, and its specific value is obtained by fitting the function form described in formula (7). (7) S9. Calculate the actual liquid flow rate. Q l (8) in, This represents the dynamic viscosity of the liquid.

2. The method for measuring the phase flow rate of moist gas based on disturbance wave height and vortex flow meter according to claim 1, characterized in that: Extracting vortex shedding frequency using the FFT algorithm f vs .

3. The method for measuring the phase flow rate of moist gas based on disturbance wave height and vortex flow meter according to claim 1, characterized in that: The gas phase volumetric flow rate is predicted by using the liquid film thickness, and the relative error of the gas phase volumetric flow rate prediction is within ±2%.

4. The method for measuring the phase flow rate of moist gas based on disturbance wave height and vortex flow meter according to claim 3, characterized in that: Relative error = (predicted value - actual value) / actual value × 100.

5. The method for measuring the phase flow rate of moist gas based on disturbance wave height and vortex flow meter according to claim 1, characterized in that: The prediction of liquid phase flow rate under different operating conditions has a relative error controlled within ±15%.

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