Method and device for measuring high-gas-liquid-ratio gas-liquid two-phase flow and liquid holdup based on three-dimensional differential pressure

Abstract

The invention discloses a high-gas-liquid-ratio gas-liquid two-phase flow and liquid holdup measurement method and device based on three-dimensional differential pressure, and the method comprises the steps: applying a centrifugal force to a gas-liquid two-phase flow through a centrifuge, and generating a stable gas nucleus-liquid ring separation structure; measuring radial differential pressure, axial differential pressure, temperature and pressure values of the centrifuge in real time; establishing a liquid holdup calculation model based on the differential pressure ratio of the radial differential pressure and the axial differential pressure, and obtaining the liquid holdup according to the liquid holdup calculation model; calculating a friction coefficient and corrected gas phase density according to the temperature and pressure values; and based on the mapping relation between the axial differential pressure and the gas phase apparent velocity and the gas state equation, the gas-liquid two-phase flow is calculated according to the liquid holdup, the friction coefficient and the corrected gas phase density. According to the invention, a high-precision, separation-free and fast-response industrial-grade solution is realized, and a new-generation measuring tool is provided for the key fields of shale gas exploitation, submarine oil and gas pipeline transportation and the like.

Description

Technical Field

[0001] This invention relates to the field of multiphase flow measurement technology, specifically to a method and apparatus for measuring the flow rate and liquid holdup of a high gas-liquid ratio two-phase flow based on three-dimensional differential pressure. Background Technology

[0002] Gas-liquid two-phase flow measurement is a key technological foundation for analyzing natural gas well production dynamics, predicting well productivity, and optimizing resource development strategies. It is also a core component of industrial processes such as chemical engineering and environmental monitoring. Currently, onshore oil and gas fields are generally in the mid-to-late stages of development, with declining natural gas production accompanied by a continuous increase in water production. Accurate and timely optimization of drainage and gas production processes urgently requires high-precision gas-liquid two-phase flow measurement.

[0003] Existing commercial multiphase flow meters are mainly based on technologies such as X-ray methods, ultrasonic methods, and capacitance probes, which have the following significant drawbacks: 1. The capacitance / conductivity method is significantly affected by flow pattern evolution, resulting in insufficient measurement stability; the microwave method requires complex flow pattern calibration, and the signal-to-noise ratio of liquid phase characteristic signals is low under high gas-liquid ratio (GVF>85%) conditions; while differential pressure instruments (such as Venturi tubes and orifice plates) have measurement errors exceeding 20% ​​under gas-dominant flow patterns due to gas phase compressibility and interphase slip effects. 2. Bottlenecks exist in engineering applicability: offline separation devices are bulky and cannot meet the real-time monitoring needs of wellheads, especially in space-constrained scenarios such as offshore platforms, where existing equipment struggles to balance miniaturization and high precision requirements; X-ray source-based equipment has high maintenance costs and poses radiation safety risks; multi-sensor integration solutions lead to increased equipment failure rates and a surge in signal processing complexity. 3. Defects exist in algorithm models: existing measurement models mostly rely on empirical formulas (such as the Lockhart-Martinelli model), which have insufficient parameter adaptability under transient flow patterns and high-pressure conditions, leading to accumulated and amplified calculation errors.

[0004] In summary, traditional differential pressure methods for measuring gas-liquid flow rates suffer from three major technical bottlenecks: poor model universality, high operation and maintenance costs, and high sensitivity to flow patterns. These limitations severely restrict their large-scale application in high-water-cut shale gas fields and offshore oil and gas development. Therefore, there is an urgent need to propose a method and miniaturized device for measuring high gas-liquid ratio gas-liquid two-phase flow rates and liquid holdup based on three-dimensional differential pressure to solve the aforementioned problems. Summary of the Invention

[0005] This invention provides a method and apparatus for measuring the flow rate and liquid holdup of a high gas-liquid ratio gas-liquid two-phase system based on three-dimensional differential pressure, in order to solve the technical problems of poor model universality, high operation and maintenance costs, and high sensitivity to flow patterns in existing differential pressure gas-liquid flow measurement technology.

[0006] To address the aforementioned problems, this invention provides a method for measuring the flow rate and liquid holdup of a high gas-liquid ratio gas-liquid two-phase system based on three-dimensional differential pressure, comprising:

[0007] By applying centrifugal force to the gas-liquid two-phase flow using a centrifuge, a stable gas core-liquid ring separation structure is generated.

[0008] Real-time measurement of radial differential pressure and axial differential pressure generated by the centrifuge, as well as temperature and pressure values ​​in the pipes connected to the centrifuge;

[0009] A liquid holdup calculation model is established based on the differential pressure ratio of radial and axial differential pressures. The liquid holdup is then obtained according to this model.

[0010] The friction coefficient and corrected gas phase density are calculated based on the stated temperature and pressure values.

[0011] Based on the mapping relationship between axial differential pressure and apparent gas velocity, and the gas equation of state, the gas-liquid two-phase flow rate is calculated according to the liquid holdup, friction coefficient and corrected gas density.

[0012] Furthermore, the radial differential pressure is the measured static pressure difference between the centrifuge shaft and the pipe wall; the axial differential pressure is the measured pressure drop between the upstream of the centrifuge at one pipe diameter and the downstream at three pipe diameters.

[0013] Furthermore, the liquid holdup calculation model based on the differential pressure ratio of radial and axial differential pressure includes:

[0014] The formula for calculating the liquid holdup rate is:

[0015]

[0016] In the formula, r o R and R are the radii of the flow regulator and separator, respectively, and r g Let φ be the radius of the gas nucleus, and Δφ be the thickness of the liquid film.

[0017] Furthermore, the calculation of the friction coefficient and corrected gas phase density based on the temperature and pressure values ​​includes:

[0018] The formula for calculating the coefficient of friction is:

[0019]

[0020] The formula for calculating the corrected gas phase density is as follows:

[0021]

[0022] In the formula, κ is the friction coefficient, and λ is the friction coefficient of a single-phase gas. To correlate the two-phase frictional resistance with the single-phase gas resistance, p is the absolute pressure of the pipeline, M is the molar mass of the gas, Z is the gas compressibility factor, R is the universal gas constant, and T is the measured value of the temperature sensor.

[0023] Furthermore, based on the mapping relationship between axial differential pressure and apparent gas velocity, and the gas equation of state, the gas-liquid two-phase flow rate is calculated according to the liquid holdup, friction coefficient, and gas phase conversion factor, including:

[0024] The formula for calculating the gas-liquid two-phase flow rate is:

[0025]

[0026] In the formula, ε is the expansion coefficient, and C q ω is the flow coefficient, a function of temperature and Reynolds number, with embedded real-time temperature / pressure compensation. ρ′ is the mixing density, ρ′=ρ l H L +ρ g (1-H L ), ρ l The preset density value; ρ g To correct for gas phase density; ΔP Zgl denoted as axial pressure difference of the gas-liquid mixture, and f is the friction coefficient between the gas and liquid phases.

[0027] The present invention also provides a high gas-liquid ratio gas-liquid two-phase flow rate and liquid holdup measurement device based on three-dimensional differential pressure, for implementing the high gas-liquid ratio gas-liquid two-phase flow rate and liquid holdup measurement method based on three-dimensional differential pressure described above, comprising: a gas core stabilization module and a pressure acquisition module coaxially nested together, and a calculation and analysis module connected to the gas core stabilization module and the pressure acquisition module;

[0028] The gas core stabilization module is used to achieve forced centrifugal separation of gas-liquid two-phase flow, generating a stable gas core-liquid ring environment, providing a physical basis for differential pressure measurement; the gas core stabilization module includes a centrifuge and a flow stabilization and separation structure; the centrifuge is used to force the fluid to generate swirling flow, and the flow stabilization and separation structure is used to form a gas core stabilization channel;

[0029] The pressure acquisition module is used to acquire the dynamic pressure signal after cyclone separation, and calculate the liquid holdup and gas flow rate parameters based on temperature and pressure compensation and pressure signal; the pressure acquisition module includes a radial differential pressure measurement unit, an axial differential pressure measurement unit and a temperature and pressure compensation module;

[0030] The calculation and analysis module is used to obtain radial differential pressure, axial differential pressure, temperature value and pressure value, and calculate the liquid holdup and gas-liquid two-phase flow rate.

[0031] Furthermore, the centrifuge includes spiral guide vanes, a spiral flow channel, and an outer casing;

[0032] The outer casing is used to constrain the flow channel boundary and provide mechanical support for the spiral guide vanes and spiral flow channel; the spiral guide vanes generate strong centrifugal force through tangential inflow; the spiral flow channel is used to guide the fluid to form a stable swirling flow, and the low-density gas phase gathers towards the axis to form a stable gas core.

[0033] Furthermore, the spiral guide vane is a spiral guide vane with an inclination angle of 45°.

[0034] Furthermore, the radial differential pressure measuring unit includes a low-pressure ring hole communicating with the axial pressure measuring tube, a high-pressure ring hole communicating with the wall pressure measuring hole, an axial differential pressure measuring unit, and a temperature and pressure compensation module;

[0035] The axial differential pressure measurement unit includes a high-pressure tapping ring hole located upstream of the centrifuge and a low-pressure tapping ring hole located downstream of the centrifuge, which are respectively connected to the high-pressure ring hole and the low-pressure ring hole.

[0036] The temperature and pressure compensation module includes a temperature sensor and a pressure sensor. The temperature sensor is integrated into the high-pressure tapping ring hole for real-time acquisition of pipeline temperature; the pressure sensor is embedded in the axial high-pressure ring hole for real-time acquisition of pressure value.

[0037] Furthermore, the centrifuge, radial differential pressure measurement unit, and axial differential pressure measurement unit are integrated into a single core measurement component, and pressure isolation between the components is achieved through differential pressure partitions and sealing strips.

[0038] Compared with the prior art, the beneficial effects of the present invention include:

[0039] (1) This invention utilizes a centrifuge to form a stable gas core-liquid ring structure in the center of the pipe. The gas phase is concentrated at the axis and the liquid phase is thrown to the outer wall. This forced separation eliminates the uncertainty caused by random changes in flow pattern in traditional two-phase flow measurement. Regardless of whether the incoming flow is slug, annular or mist, a repeatable centrifugal force distribution can be obtained in the measurement section, thereby ensuring the long-term consistency of liquid holdup and flow rate. This eliminates the measurement error caused by gas-liquid slip and flow pattern fluctuation in traditional methods and improves measurement accuracy.

[0040] (2) The liquid holdup is inverted by the ratio of radial differential pressure to axial differential pressure. This ratio is only related to the thickness of the liquid ring and the intensity of centrifugal force, and has a natural inhibitory effect on external disturbances such as pipeline vibration, pressure transients, and temperature drift. Therefore, a gas-liquid annular flow can be generated by swirling flow to suppress the influence of slug flow. At the same time, real-time compensation of temperature and pressure further eliminates the influence of changes in gas density and pipe wall friction, so that the measurement reliability can be maintained without frequent calibration on site, and there is no need to configure Venturi tubes and complex imaging equipment, which greatly reduces hardware costs.

[0041] (3) The device of the present invention only requires a centrifuge and a differential pressure tap to be embedded in the pipe section, without the need for a large separator, radiation source or high-speed rotating parts, which greatly reduces the installation space; there are no moving parts that are easy to clog or wear, and there is no need to clean up the accumulated liquid or replace the radiation source regularly. Daily maintenance is limited to routine instrument inspection, which significantly reduces operating costs and downtime risks.

[0042] In summary, this invention, through its innovative measurement mechanism of swirl-differential pressure coupling, overcomes the technical bottlenecks of "inaccurate measurement, slow response, and difficult maintenance" in high gas-liquid ratio two-phase flow, achieving a high-precision, separation-free, and fast-response industrial-grade solution. It provides a new generation of measurement tools for key fields such as shale gas extraction and subsea oil and gas transportation. Attached Figure Description

[0043] Figure 1 A schematic flowchart of a method for measuring the flow rate and liquid holdup of a high gas-liquid ratio gas-liquid two-phase system based on three-dimensional differential pressure, provided by the present invention;

[0044] Figure 2 A schematic diagram of the "gas core + liquid ring" structure after gas-liquid separation provided by the present invention;

[0045] Figure 3 A schematic diagram of the structure of a high gas-liquid ratio gas-liquid two-phase flow rate and liquid holdup measurement device based on three-dimensional differential pressure provided by the present invention;

[0046] Figure 4 This is a schematic diagram of the centrifuge structure provided by the present invention;

[0047] In the diagram, 1-Axial pressure difference high-pressure tap; 2-Radial pressure difference low-pressure annulus; 3-Helical guide vane; 4-Axial pressure difference low-pressure tap; 5-Radial pressure difference low-pressure tap; 6-Axial pressure measuring tube; 7-Radial pressure difference high-pressure annulus; 8-Helical flow channel; 9-Central flow stabilizing tube; 10-Pressure difference partition; 11-Sealing strip between pressure difference partitions; 12-Outer sleeve; 13-Radial pressure difference high-pressure annulus; 14-Axial pressure difference low-pressure annulus; 15-Axial pressure difference high-pressure annulus; 21-Flow stabilizing pressure measuring tube; 22-Guide vane. Detailed Implementation

[0048] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0049] Example 1

[0050] This invention provides a method for measuring the flow rate and liquid holdup of a high gas-liquid ratio gas-liquid two-phase system based on three-dimensional differential pressure, such as... Figure 1 As shown, Figure 1This is a flowchart illustrating the method for measuring the flow rate and liquid holdup of a high gas-liquid ratio gas-liquid two-phase system based on three-dimensional differential pressure. The method includes:

[0051] Step S101: Apply centrifugal force to the gas-liquid two-phase flow using a centrifuge to generate a stable gas core-liquid ring separation structure;

[0052] Step S102: Measure the radial differential pressure, axial differential pressure, temperature, and pressure values ​​generated downstream of the centrifuge in real time;

[0053] Step S103: Establish a liquid holdup calculation model based on the differential pressure ratio of radial differential pressure and axial differential pressure, and obtain the liquid holdup according to the liquid holdup calculation model;

[0054] Step S104: Calculate the friction coefficient and corrected gas phase density based on the temperature and pressure values;

[0055] Step S105: Based on the mapping relationship between axial differential pressure and apparent gas velocity, and the gas state equation, calculate the gas-liquid two-phase flow rate according to the liquid holdup, friction coefficient and corrected gas density.

[0056] This embodiment provides a method for measuring the flow rate and liquid holdup of high gas-liquid ratio two-phase flow based on three-dimensional differential pressure. By forcibly forming a gas core-liquid ring structure using a centrifuge, it eliminates flow pattern randomness and ensures long-term consistency of liquid holdup and flow rate. Utilizing the differential pressure ratio combined with temperature and pressure compensation, it naturally suppresses vibration, transients, and drift, eliminating the need for frequent on-site calibration. This method reveals that radial differential pressure is insensitive to gas phase velocity at high gas-liquid ratios (GVF>85%) (analogous to the high viscosity region of heavy oil), and proposes a dual differential pressure ratio function model. The introduction of a gas phase reduction coefficient solves the modeling problem of gas-liquid interaction. Furthermore, this method eliminates the need for a venturi tube in hardware, achieving dual differential pressure measurement using only a centrifuge, simplifying the structure and reducing pressure loss.

[0057] As a specific embodiment, in step S101, centrifugal force is applied to the gas-liquid two-phase flow through a centrifuge to generate a stable gas nucleus-liquid ring separation structure, which is achieved through forced gas-liquid separation by the centrifuge. The principle is that the gas phase accumulates at the tube core: the low-density gas phase experiences less centrifugal force, forming a stable gas nucleus; the liquid phase flows along the wall: the high-density liquid phase experiences greater centrifugal force, forming an annular liquid film. Based on this principle, radial differential pressure (RDP) and axial differential pressure (ADP) are generated: radial differential pressure refers to the static pressure difference between the axis and the tube wall, mainly characterizing the liquid holdup (H). L Axial differential pressure refers to the pressure drop across the centrifuge, primarily characterizing the gas flow rate (Vg).

[0058] like Figure 2 As shown, Figure 2 A schematic diagram of the "gas core + liquid ring" structure after gas-liquid separation is shown.

[0059] In a preferred embodiment, in step S102, the radial differential pressure is the measured static pressure difference between the centrifuge shaft and the pipe wall; the axial differential pressure is the measured pressure drop between the upstream of the centrifuge at one pipe diameter and the downstream at three pipe diameters.

[0060] In a preferred embodiment, step S103, establishing the liquid holdup calculation model based on the differential pressure ratio of radial differential pressure and axial differential pressure, includes:

[0061] The formula for calculating the liquid holdup rate is:

[0062]

[0063] In the formula, r o R and R are the radii of the flow regulator and separator, respectively, and r g Let φ be the radius of the gas nucleus, and Δφ be the thickness of the liquid film.

[0064] In a preferred embodiment, step S104, calculating the friction coefficient and corrected gas phase density based on the temperature and pressure values, includes:

[0065] The formula for calculating the coefficient of friction is:

[0066]

[0067] The formula for calculating the corrected gas phase density is as follows:

[0068]

[0069] In the formula, κ is the friction coefficient, and λ is the friction coefficient of a single-phase gas. To correlate the two-phase frictional resistance with the single-phase gas resistance, p is the absolute pressure of the pipeline, M is the molar mass of the gas, Z is the gas compressibility factor, R is the universal gas constant, and T is the measured value of the temperature sensor.

[0070] In a preferred embodiment, in step S105, based on the mapping relationship between axial differential pressure and apparent gas velocity, and the gas equation of state, the gas-liquid two-phase flow rate is calculated according to the liquid holdup, friction coefficient, and gas phase conversion factor, including:

[0071] The formula for calculating the gas-liquid two-phase flow rate is:

[0072]

[0073] In the formula, ε is the expansion coefficient, and C q ω is the flow coefficient, a function of temperature and Reynolds number, with embedded real-time temperature / pressure compensation. ρ′ is the mixing density, ρ′=ρ l H L +ρ g (1-HL ), ρ l The preset density value; ρ g To correct for gas phase density; ΔP Zgl denoted as axial pressure difference of the gas-liquid mixture, and f is the friction coefficient between the gas and liquid phases.

[0074] Example 2

[0075] This invention also provides a high gas-liquid ratio gas-liquid two-phase flow rate and liquid holdup measurement device based on three-dimensional differential pressure, used to implement the high gas-liquid ratio gas-liquid two-phase flow rate and liquid holdup measurement method based on three-dimensional differential pressure described above. The device includes: a gas core stabilization module and a pressure acquisition module coaxially nested together, and a calculation and analysis module connected to the gas core stabilization module and the pressure acquisition module.

[0076] The gas core stabilization module is used to achieve forced swirling separation of gas-liquid two-phase flow, generating a stable gas core-liquid ring environment, providing a physical basis for differential pressure measurement; the gas core stabilization module includes a centrifuge and a flow stabilization and separation structure; the centrifuge is used to force the fluid to generate swirling flow, and the flow stabilization and separation structure forms a gas core stabilization channel;

[0077] The pressure acquisition module is used to acquire the dynamic pressure signal after cyclone separation, and calculate the liquid holdup and gas flow rate parameters based on temperature and pressure compensation and pressure signal; the pressure acquisition module includes a radial differential pressure measurement unit, an axial differential pressure measurement unit and a temperature and pressure compensation module;

[0078] The calculation and analysis module is used to obtain radial differential pressure, axial differential pressure, temperature value and pressure value. According to the high gas-liquid ratio gas-liquid two-phase flow rate and liquid holdup measurement method based on three-dimensional differential pressure described in Example 1, the liquid holdup and gas-liquid two-phase flow rate values ​​are calculated.

[0079] In a preferred embodiment, the centrifuge includes spiral guide vanes, a spiral flow channel, and an outer casing;

[0080] The outer casing is used to constrain the flow channel boundary and provide mechanical support for the spiral guide vanes and spiral flow channel; the spiral guide vanes generate strong centrifugal force through tangential inflow; the spiral flow channel is used to guide the fluid to form a stable swirling flow, and the low-density gas phase gathers towards the axis to form a stable gas core.

[0081] In a preferred embodiment, the spiral guide vane is a spiral guide vane with an inclination angle of 45°.

[0082] In a preferred embodiment, the radial differential pressure measuring unit includes a low-pressure ring hole communicating with the axial pressure measuring tube, a high-pressure ring hole communicating with the wall pressure measuring hole, an axial differential pressure measuring unit, and a temperature and pressure compensation module.

[0083] The axial differential pressure measurement unit includes a high-pressure tapping ring hole located upstream of the centrifuge and a low-pressure tapping ring hole located downstream of the centrifuge, which are respectively connected to the high-pressure ring hole and the low-pressure ring hole.

[0084] The temperature and pressure compensation module includes a temperature sensor and a pressure sensor. The temperature sensor is integrated into the high-pressure tapping ring hole for real-time acquisition of pipeline temperature; the pressure sensor is embedded in the axial high-pressure ring hole for real-time acquisition of pressure value.

[0085] In a preferred embodiment, the centrifuge, radial differential pressure measurement unit, and axial differential pressure measurement unit are integrated into a single core measurement component, and pressure isolation between the components is achieved through differential pressure partitions and sealing strips.

[0086] like Figure 3 As shown, Figure 3 A schematic diagram of the coaxial nested assembly of the gas core stabilization module and the pressure acquisition module is shown. Figure 3 In the centrifuge, the spiral guide vanes 3, the spiral flow channel 8, and the outer casing 12 constitute the centrifuge. The central flow stabilizing pipe 9 passes through the axial pressure measuring pipe 6, forming a flow stabilizing and separating structure. During measurement, the radial differential pressure can be measured by connecting the axial pressure measuring pipe 6 to the radial differential low-pressure tap 5, and connecting the radial differential low-pressure annulus 2 and the radial differential high-pressure annulus 7. The axial differential pressure is measured by measuring the pressure drop at upstream 1D and downstream 3D of the centrifuge, connected... Figure 3 In the middle, the axial pressure difference low pressure tap 4 is connected to the axial pressure difference low pressure annulus 14, and the axial pressure difference high pressure annulus 15 and the axial pressure difference low pressure annulus 14 can obtain the axial pressure difference.

[0087] The working principle of this device is as follows: Gas and liquid phases enter the pipe from the left. Through the forced separation action of the centrifuge, the two phases undergo a brief phase separation within the pipe. This separation also creates a radial static pressure change, with lower pressure at the pipe center and higher pressure at the pipe wall. This radial pressure difference can be measured by a differential pressure sensor and serves as one of the signals for identifying the flow rate of the gas and liquid phases. Furthermore, the centrifuge itself has an axial throttling effect, creating an axial pressure difference between the gas and liquid phases. This axial pressure difference is another characteristic signal for quantitatively describing the flow rate. By combining these two pressure differences, a method for measuring gas-liquid flow rate and phase content is formed. Finally, an online measurement model for gas-liquid two-phase flow rate is established through inversion.

[0088] like Figure 4 As shown, Figure 4A schematic diagram of a centrifuge is shown, featuring blades tilted at a 45° angle. The ratio of the blade diameter Dp to the outer diameter D of the flow stabilizing tube is Dp / D = 1.8. Centrifugal force concentrates the gas phase at the axis to form a continuous and stable gas nucleus, while the liquid phase is thrown towards the outer wall to form a uniform liquid ring, completely shielding the measurement area from interference from the inlet flow pattern (slug, annular, mist). This forced stratification ensures that the differential pressure signal reflects only the liquid ring thickness and centrifugal force, and is no longer affected by random phase distribution.

[0089] This invention discloses a method and apparatus for measuring the flow rate and liquid holdup of high gas-liquid ratio two-phase flow based on three-dimensional differential pressure. By forcibly forming a gas core-liquid ring structure using a centrifuge, the randomness of the flow pattern is eliminated, ensuring long-term consistency of liquid holdup and flow rate. The differential pressure ratio, combined with temperature and pressure compensation, naturally suppresses vibration, transients, and drift, eliminating the need for frequent on-site calibration. This method reveals that radial differential pressure is insensitive to gas phase velocity at high gas-liquid ratios (GVF>85%) (analogous to the high viscosity region of heavy oil), and proposes a dual differential pressure ratio function model. The introduction of a gas phase reduction coefficient solves the modeling problem of gas-liquid interaction. In terms of hardware, the Venturi tube design is eliminated, and dual differential pressure measurement is achieved solely using a centrifuge, simplifying the structure and reducing pressure loss.

[0090] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for measuring high gas-liquid ratio gas-liquid two-phase flow and liquid holdup based on three-dimensional differential pressure, characterized in that, The application relates to a method for measuring gas-liquid two-phase flow, and belongs to the technical field of flow measurement. A centrifugal force is applied to the gas-liquid two-phase flow by a centrifugal device to generate a stable gas core-liquid ring separation structure; Radial differential pressure, axial differential pressure, temperature and pressure values in a pipeline connected with the centrifugal device generated by the centrifugal device are measured in real time; A liquid holdup rate calculation model is established based on a differential pressure ratio of the radial differential pressure and the axial differential pressure, and the liquid holdup rate is obtained according to the liquid holdup rate calculation model: Friction coefficients and corrected gas phase densities are calculated according to the temperature and pressure values; Gas-liquid two-phase flow is calculated according to the liquid holdup rate, the friction coefficients and the corrected gas phase densities based on a mapping relationship between the axial differential pressure and the gas phase superficial velocity and a gas state equation.

2. The three-dimensional differential pressure based high gas-liquid ratio gas-liquid two-phase flow and liquid holdup measurement method according to claim 1, characterized by, The radial differential pressure is a static pressure difference between the shaft center of the centrifugal device and the pipeline wall measured, and the axial differential pressure is a pressure drop between a position one pipe diameter upstream of the centrifugal device and a position three pipe diameters downstream of the centrifugal device.

3. The method of claim 1, wherein the method is a three-dimensional differential pressure based high gas-liquid ratio gas-liquid two-phase flow and liquid holdup measurement method, characterized in that, The liquid holdup rate calculation model is established based on the differential pressure ratio of the radial differential pressure and the axial differential pressure, and includes: The liquid holdup rate calculation formula is: where r o and R are the radii of the steady flow tube and the centrifuge, respectively, r g is the gas core radius, and Δφ is the liquid film thickness.

4. The method of claim 1, wherein the method is a three-dimensional differential pressure based high gas-liquid ratio gas-liquid two-phase flow and liquid holdup measurement method, characterized in that, The friction coefficients and the corrected gas phase densities are calculated according to the temperature and pressure values, and include: The calculation formula of the friction coefficients is: The calculation formula of the corrected gas phase densities is: where k is the friction factor, and λ is the single-phase gas friction factor, where k is the friction factor, and λ is the single-phase gas friction factor, where k is the friction factor, and λ is the single-phase gas friction factor, 5. The method of claim 4, wherein the three-dimensional differential pressure based high gas-liquid ratio gas-liquid two-phase flow and liquid holdup measurement method is characterized by, The gas-liquid two-phase flow is calculated according to the liquid holdup rate, the friction coefficients and the gas phase conversion coefficients based on the mapping relationship between the axial differential pressure and the gas phase superficial velocity and the gas state equation, and includes: The calculation formula of the gas-liquid two-phase flow is: where ε is the expansion factor, C q is the flow coefficient, ω is a function of temperature and Reynolds number, ρ' is the mixture density, ρ' = ρ l H L + ρ g (1 - H L ), ρ l is the preset density value; ρ g is the corrected gas density; ΔP Zgl is the axial pressure difference of the gas-liquid mixture, and f is the gas-liquid two-phase friction factor.

6. A three-dimensional differential pressure based gas-liquid two-phase flow and liquid holdup measurement device for high gas-liquid ratio, the device being configured to implement the three-dimensional differential pressure based gas-liquid two-phase flow and liquid holdup measurement method of any one of claims 1-5, the device comprising: The application relates to a method for measuring gas-liquid two-phase flow, and belongs to the technical field of flow measurement. A coaxially nested gas core stabilizing module and a pressure collecting module and a calculation analysis module connected with the gas core stabilizing module and the pressure collecting module are arranged; The gas core stabilizing module is used for generating a stable gas core-liquid ring environment after forced cyclone separation of the gas-liquid two-phase flow to provide a physical basis for differential pressure measurement, and the gas core stabilizing module includes a centrifugal device and a stable flow and separation structure; the centrifugal device is used for forcing fluid to generate cyclone, and the stable flow and separation structure is used for forming a gas core stabilizing channel; The pressure collecting module is used for collecting dynamic pressure signals after cyclone separation and calculating liquid holdup rate and gas phase flow parameters based on temperature and pressure compensation and pressure signals; the pressure collecting module includes a radial differential pressure measuring unit, an axial differential pressure measuring unit and a temperature and pressure compensation module; The calculation analysis module is used for obtaining radial differential pressure, axial differential pressure, temperature values and pressure values and calculating liquid holdup rate and gas-liquid two-phase flow values.

7. The three-dimensional differential pressure based high gas-liquid ratio gas-liquid two-phase flow and liquid holdup measurement device of claim 1, wherein, The centrifugal device includes helical guide vanes, a helical flow channel and an outer sleeve tube; The outer sleeve tube is used for restricting a flow channel boundary and providing mechanical support for the helical guide vanes and the helical flow channel; the helical guide vanes generate strong centrifugal force through tangential inflow; and the helical flow channel is used for guiding fluid to form stable cyclone, and low-density gas phase is gathered to the shaft center to form a stable gas core.

8. The three-dimensional differential pressure based high gas-liquid ratio gas-liquid two-phase flow and liquid holdup measurement device of claim 7, wherein, The helical guide vanes are helical guide vanes with an inclination angle of 45 degrees.

9. The three-dimensional differential pressure based high gas-liquid ratio gas-liquid two-phase flow and liquid holdup measurement device of claim 6, wherein, The radial differential pressure measuring unit includes a low-pressure ring hole communicated with a shaft center pressure measuring pipe, a high-pressure ring hole communicated with a wall surface pressure measuring hole, an axial differential pressure measuring unit and a temperature and pressure compensation module; The axial differential pressure measuring unit includes a high-pressure pressure taking ring hole arranged at an upstream position of the centrifugal device and a low-pressure pressure taking ring hole arranged at a downstream position, and the high-pressure ring hole and the low-pressure ring hole are connected with the high-pressure pressure taking ring hole and the low-pressure pressure taking ring hole respectively. The temperature and pressure compensation module comprises a temperature sensor and a pressure sensor, the temperature sensor is integrated at the high-pressure tapping hole for collecting the pipeline temperature in real time, and the pressure sensor is embedded in the axial high-pressure ring hole for collecting the pressure value in real time.

10. The three-dimensional differential pressure based high gas-liquid ratio gas-liquid two-phase flow and liquid holdup measurement device according to any one of claims 6-9, wherein, The centrifugal separator, the radial differential pressure measuring unit and the axial differential pressure measuring unit are integrated in a single core measuring component, and the components are pressure-isolated through differential pressure partitioning barriers and sealing strips.

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