A forced annular flow flow measuring device with gas-liquid two-phase flow dynamic regulation

Abstract

This invention relates to a forced annular flow flow measurement device for dynamic control of gas-liquid two-phase flow, comprising a cyclone separator (1) for regularizing the flow pattern, a front-end liquid film measurement sensor (2), a rear-end liquid film measurement sensor (3), and a venturi flow meter (7) arranged sequentially from upstream to downstream in a measuring pipe; a guide channel (8) is provided in the measuring pipe section between the front-end liquid film measurement sensor (2) and the rear-end liquid film measurement sensor (3), and a liquid phase control window (4) is provided outside this section of the measuring pipe, which is connected to the measuring pipe through the guide channel (8); the lower part of the liquid phase control window (4) is connected to a bypass, and a control valve (5) and a liquid phase flow meter (6) are provided on the bypass.

Description

Technical Field

[0001] This invention pertains to all application areas of gas-liquid two-phase flow measurement, and relates to a forced annular flow flow measurement device for dynamic control of gas-liquid two-phase flow. Background Technology

[0002] Gas-liquid two-phase flow is widely present in industrial production and daily life. Systems such as centralized heating, wastewater treatment, natural gas extraction and transportation, and nuclear power water cooling systems are all closely related to gas-liquid two-phase flow. Flow rate is a crucial characteristic parameter of gas-liquid two-phase flow. Accurate measurement of two-phase flow flow rate plays a vital role in the manufacturing and design of facilities and equipment, the supervision and assurance of production safety, the management and control of production processes, the development and utilization of energy, and the innovation of engineering equipment.

[0003] The flow patterns in gas-liquid two-phase flow are complex and varied, exhibiting multiple patterns such as bubbly flow, slug flow, plug flow, annular flow, and droplet flow at the pipe cross-section. This leads to drastic fluctuations in the instrument output signal, making it difficult to guarantee the reliability and accuracy of flow measurement results. To address this, researchers proposed using a hydrocyclone to force the randomly distributed gas-liquid two-phase flow into a regularly distributed helical annular flow, effectively improving the flow meter's dependence on the inlet flow pattern. Currently, forced annular flow flow measurement technology has achieved the measurement of wet gas flow with low liquid holdup. However, in actual industrial applications, the gas flow rate, liquid flow rate, and liquid holdup of gas-liquid two-phase flow vary greatly. In many cases, it is difficult to form a stable helical annular flow using a hydrocyclone, thus affecting the accuracy of forced annular flow flow measurement and potentially leading to measurement failure. Summary of the Invention

[0004] This invention addresses the difficulty in flow measurement due to the complex flow patterns and wide liquid holdup range in gas-liquid two-phase flow. It proposes a novel forced annular flow measurement device for dynamic control of gas-liquid two-phase flow. The technical solution is as follows:

[0005] A forced annular flow flow measurement device for dynamic control of gas-liquid two-phase flow includes a cyclone separator 1 for regularizing the flow pattern, a front-end liquid film measurement sensor 2, a rear-end liquid film measurement sensor 3, and a venturi flow meter 7, arranged sequentially from upstream to downstream in a measurement pipe; a guide channel 8 is provided in the measurement pipe section between the front-end liquid film measurement sensor 2 and the rear-end liquid film measurement sensor 3, and a liquid phase control window 4 is provided on the outside of this section of the measurement pipe, which is connected to the measurement pipe through the guide channel 8; the lower part of the liquid phase control window 4 is connected to a bypass, and a control valve 5 and a liquid phase flow meter 6 are provided on this bypass.

[0006] Furthermore, the lower part of the liquid phase control window 4 is connected via a bypass to the measuring pipe downstream of the Venturi flow meter 7.

[0007] Furthermore, there are at least three flow guide channels 8, which are evenly distributed on a cross section of the measuring pipe section.

[0008] Furthermore, the slotting direction of the guide groove 8 is consistent with the swirling direction of the hydrocyclone 1.

[0009] Furthermore, the opening control signal of the control valve 5 is determined based on the liquid film thickness collected by the front liquid film measurement sensor 2 and the rear liquid film measurement sensor 3.

[0010] The forced annular flow flow measurement device for dynamic control of gas-liquid two-phase flow proposed in this invention has the following main advantages:

[0011] 1) The cyclone separator effectively reduces the dependence of the flow meter on the inlet flow pattern when measuring flow rate;

[0012] 2) The liquid phase portion of the gas-liquid two-phase flow can be separated by the liquid phase control device, so that the spiral annular flow is maintained within the range that ensures the measurement accuracy of the Venturi flowmeter, effectively reducing the difficulty of two-phase flow measurement, widening the flow measurement range, and improving the flow measurement accuracy. Attached Figure Description

[0013] Figure 1 A forced annular flow measurement device with dynamic liquid phase control. Figure 1 In the middle: 1. Hydrocyclone; 2. Front-end liquid film measurement sensor; 3. Rear-end liquid film measurement sensor; 4. Liquid phase control window; 5. Dynamic control valve; 6. Liquid phase flow meter; 7. Venturi flow meter; 8. Guide channel.

[0014] Figure 2 Example diagram of a flow channel. Detailed Implementation

[0015] The forced annular flow flow measurement device for dynamic control of gas-liquid two-phase flow of the present invention includes a cyclone separator 1, a front-end liquid film measurement sensor 2, a rear-end liquid film measurement sensor 3, a liquid phase control window 4, a dynamic control valve 5, a liquid phase flow meter 6, a Venturi flow meter 7, and a guide channel 8. The cyclone separator 1 is used to regularize the flow pattern and generate a spiral annular flow. The front-end liquid film measurement sensor 2 and the rear-end liquid film measurement sensor 3 are used to measure the liquid film thickness of the spiral annular flow. These sensors can be any sensors capable of measuring liquid film thickness information, such as optical sensors (e.g., high-speed cameras), acoustic sensors (e.g., ultrasonic sensors), and electrical sensors (e.g., conductivity probes). The front-end liquid film measurement sensor 2 and the rear-end liquid film measurement sensor 3 measure the liquid film thickness of the spiral annular flow before and after control, respectively, and use this as the basis for adjusting the dynamic control valve 5. The adjustment method can be any dual-input single-output control system, such as a cascade control system or an artificial intelligence control system. The liquid phase control window 4 is used to guide the liquid film thickness of the spiral annular flow... The membrane is partially separated and collected; the dynamic control valve 5 is used to change the speed of liquid phase separation, so that the spiral annular flow liquid phase in the pipeline is stabilized within a certain range; the liquid phase flow meter 6 is used to measure the flow rate of the liquid phase separated by the liquid phase control window 4, and can be any flow meter that can measure the liquid phase flow rate, such as differential pressure flow meter, turbine flow meter, vortex flow meter, electromagnetic flow meter, etc.; the Venturi flow meter 7 is used to measure the mass flow rate of the spiral annular flow with a low liquid content after control, since the flow meter structure has little impact on the spiral annular flow pattern; in this embodiment, there are four guide channels 8, which are evenly distributed on the same cross section of the measuring pipeline, and are used to separate the liquid film of the spiral annular flow. The opening method, number and size can be adjusted according to the actual scenario.

[0016] The specific implementation of the present invention is as follows:

[0017] 1) First, after the gas-liquid two-phase flow passes through the hydrocyclone 1, due to the density difference between the gas and liquid phases, under the action of centrifugal force, the gas phase mainly concentrates in the center of the pipe to form a gas core, and the liquid phase is deposited on the wall to form a liquid film, thus forcing the complex gas-liquid two-phase flow into a spiral annular flow.

[0018] 2) Then, the thickness of the liquid film in the spiral annular flow before and after the liquid phase control window 4 is measured by the front liquid film measurement sensor 2 and the rear liquid film measurement sensor 3. The liquid film thickness information is input into the control system, and the opening control signal of the dynamic control valve 5 is output to adjust the opening of the dynamic control valve 5 in real time. The liquid film of the separated part is separated by the guide channel 8 opened on the measuring pipe and the liquid phase control window 4. The separation speed is determined by the dynamic control valve 5, and the flow rate of the separated liquid phase is measured by the liquid phase flow meter 6.

[0019] 3) Finally, the mass flow rate of the spiral annular flow after regulation is measured using the Venturi flow meter 7. After the flow measurement is completed, the liquid phase separated by the liquid phase regulation window 4 is reintroduced into the pipeline so that the gas-liquid two-phase flow can continue to flow backward.

[0020] This invention presents a forced annular flow flow measurement device for dynamic control of gas-liquid two-phase flow, which has a wider measurement range and higher measurement accuracy. Combining a hydrocyclone, a liquid film measurement sensor, a liquid phase control window, and a Venturi flowmeter, it can effectively and accurately measure the flow rate of gas-liquid two-phase flow, overcoming the influence of flow pattern on flow measurement. It can also effectively measure gas-liquid two-phase flows with high liquid content. The specific embodiments described above provide a detailed description of this invention, but are not limited to the methods described above. For those skilled in the art, improvements, substitutions, and uses of this method based on the above-described inventive principles are all within the protection scope of this invention.

Claims

1. A forced annular flow flow measurement device for dynamic control of gas-liquid two-phase flow, comprising a cyclone separator (1) for regularizing the flow pattern, a front-end liquid film measurement sensor (2), a rear-end liquid film measurement sensor (3), and a Venturi flow meter (7) arranged sequentially from upstream to downstream in a measuring pipe; a guide channel (8) is provided in the measuring pipe section between the front-end liquid film measurement sensor (2) and the rear-end liquid film measurement sensor (3), and a liquid phase control window (4) is provided outside this section of the measuring pipe, the liquid phase control window (4) being connected to the measuring pipe through the guide channel (8); the lower part of the liquid phase control window (4) is connected to a bypass, and a control valve (5) and a liquid flow meter are provided on this bypass. Phase flow meter (6); the lower part of the liquid phase control window (4) is connected to the measuring pipe downstream of the Venturi flow meter (7) through the bypass; the slotting direction of the guide groove (8) is consistent with the swirling direction of the hydrocyclone (1); the liquid film thickness of the spiral annular flow before and after the liquid phase control window (4) is measured by the front liquid film measurement sensor (2) and the rear liquid film measurement sensor (3); the liquid film of the separated part is separated by the guide groove (8) and the liquid phase control window (4) opened on the measuring pipe, and the separation speed is determined by the control valve (5); the opening control signal of the control valve (5) is determined according to the liquid film thickness collected by the front liquid film measurement sensor (2) and the rear liquid film measurement sensor (3).

2. The forced annular flow flow measurement device for dynamic control of gas-liquid two-phase flow according to claim 1, characterized in that, There are at least three flow guide channels (8), which are evenly distributed on one cross section of the measuring pipe section.

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