Device and method for analyzing characteristics of annular flow phase interface in circular pipe under inclined condition

Abstract

The invention discloses a device and a method for analyzing the characteristics of an annular flow phase interface in a circular tube under an inclined condition, and belongs to the technical field of nuclear reactor thermotechnical experiments, the device comprises a circular tube, the included angle between the circular tube and the ground can be freely adjusted in the space, and at least two groups of liquid film thickness measuring points are uniformly arranged on the opposite sides of the inner circumferential wall of the circular tube along the annular direction; the probe comprises a fixed measuring wire and a movable measuring wire, and the probe is used for measuring the circumferential liquid film thickness of the annular flow on the inner wall of the circular tube; and the gas-liquid supply equipment is used for providing annular flow into the circular pipe. Multiple groups of liquid film thickness measuring points are arranged on the inner circumferential wall of the circular tube, the probe comprising the fixed measuring wire and the movable measuring wire is adopted, the liquid film thickness of the annular flow in the circular tube is accurately measured, key data are provided for researching the phase interface characteristics of the annular flow, the included angle between the circular tube and the ground is freely adjusted in the space, and the measurement accuracy is improved. The experiment requirements under different inclination angles can be met, so that the phase interface characteristics of the annular flow in the circular pipe under different inclination angles can be obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear reactor thermal-hydraulic experiments, and in particular to an analysis device and method for the phase interface characteristics of annular flow in a circular tube under inclined conditions. Background Art

[0002] Annular flow is a very important flow pattern in the study of reactor thermal-hydraulics. For a uniformly heated flow channel, after the single-phase water at the inlet is heated, the temperature gradually rises, and it enters subcooled boiling and saturated boiling in turn. After the fluid starts saturated boiling, the main flow pattern experienced is annular flow. As the heat flux continues to increase, the liquid film of the annular flow gradually dries out, boiling crisis occurs, the heat transfer of the flow channel deteriorates, and burnout phenomenon occurs. In annular flow, the liquid film flows along the wall of the flow channel, and the gas core with entrained liquid droplets flows in the center of the channel. There is continuous liquid exchange between the gas core and the liquid film, that is, the liquid droplets in the gas core settle towards the liquid film surface, and at the same time, the high-speed flow of the gas core will entrain the liquid film to generate liquid droplets and enter the gas core to form entrainment of liquid droplets. The source of steam in the gas core is mainly vaporization at the gas-liquid interface. The liquid film distribution in the flow channel is uniform under vertical conditions, and the wide-side liquid film and the narrow-side liquid film are symmetrically distributed respectively. When the flow channel is inclined, the liquid film is no longer symmetrically and uniformly distributed. Due to the action of gravity, the liquid film tends to deposit at the bottom of the flow channel, so there is a phenomenon that the liquid film at the bottom of the flow channel is thick and the top is thin. The thinning of the top liquid film triggers the critical state in advance, reducing the safety heat flux threshold of the flow channel. In the past few decades, a large number of studies have been carried out on the phase interface characteristics of annular flow in vertical channels at home and abroad, providing important support for the safety analysis of nuclear reactors.

[0003] A floating nuclear power plant refers to a movable nuclear power plant built on a floating platform, which can be used for power generation, seawater desalination, and heating, and can meet the special needs of regional power supply, regional heating, offshore oil exploitation, chemical industry, polar or remote areas, islands, etc. When the floating nuclear power plant moves in the ocean, it will be affected by wind and waves and generate motions such as hull inclination, undulation or swaying. Therefore, the phase interface characteristics of annular flow in a vertical channel under inclined conditions are of great significance for the safety analysis of floating nuclear power plants.

[0004] In view of the above problems, there is an urgent need for an analysis device and method for the phase interface characteristics of annular flow in a circular tube under inclined conditions. Summary of the Invention

[0005] In view of this, the present application provides an analysis device and method for the phase interface characteristics of annular flow in a circular tube under inclined conditions. The main purpose is to solve the technical problems of realizing annular flow patterns in different mass flow rate ranges and accurately obtaining the phase interface distribution characteristics and laws of annular flow under vertical and inclined conditions.

[0006] According to the first aspect of the present invention, there is provided an analysis device for the characteristics of the annular flow phase interface in a circular tube under inclined conditions, comprising: a circular tube, which can be arbitrarily adjusted in space to form an angle with the ground, and at least two groups of liquid film thickness measurement points are evenly arranged on the inner circumferential wall of the circular tube along the annular direction; A probe, including a fixed measurement wire and a movable measurement wire, which is used to measure the liquid film thickness in the circumferential direction of the annular flow on the inner wall of the circular tube; A gas-liquid supply device, which is used to provide annular flow into the circular tube.

[0007] Further, the gas-liquid supply device includes: a water tank, which is used to provide a solution into the circular tube; An air compressor, which is used to provide a gas source into the circular tube; A pump is provided between the water tank and the circular tube, and downstream of the pump includes: a liquid flowmeter, which is used to adjust the liquid phase flow rate entering the circular tube; A flow control valve, which jointly adjusts the liquid phase flow rate entering the circular tube with the pump.

[0008] Further, a gas flowmeter and a flow pattern control valve are provided between the air compressor and the circular tube; The flow pattern control valve obtains the gas phase flow rate required for annular flow according to the liquid phase flow rate, and adjusts the flow rate of the air compressor to a preset annular flow rate.

[0009] Further, the analysis device further includes: a droplet measurement device, which is connected to the outlet end of the circular tube; The droplet measurement device at least includes: a liquid film collection container, a leakage tube; For the leakage tube, the annular flow coming out of the circular tube is introduced into the leakage tube. One end of the leakage tube is connected to the liquid film collection container, and overflow holes are arranged on the inner wall of the leakage tube near the circular tube end. The liquid of the liquid film enters the liquid film collection container through the overflow holes.

[0010] Further, the droplet measurement device further includes: a gas core droplet collection container, a connecting pipe; The connecting pipe includes a first pipe and a second pipe, and there is an angle in the vertical direction at the connection of the first pipe and the second pipe; One end of the first pipe is connected to the outlet of the leakage tube, and the second pipe is communicated with the gas core droplet collection container.

[0011] Further, the analysis device further includes: a discharge pipe, which is respectively communicated with the connecting pipe and the gas core droplet collection container; An air-water separator is arranged inside the discharge pipe, which is used to separate gas and liquid for the gas core.

[0012] Furthermore, the diameter of the leakage flow tube is the same as that of the circular tube.

[0013] Furthermore, a plurality of the probes are uniformly arranged along the circumferential direction for each group of the liquid film thickness measurement points.

[0014] Furthermore, according to the second aspect of the present invention, there is provided an analysis method for the annular flow phase interface characteristics in a circular tube under an inclined condition, and the analysis method is implemented by using the analysis device in the above-mentioned invention content; The method includes: S1. Start the analysis device, supply gas-liquid two-phase fluid into the circular tube through a pump, a flow control valve, an air compressor and a flow pattern control valve, and establish the annular flow required for the experiment; S2. When the potential difference between the movable measurement wire and the fixed measurement wire is adjusted to zero, stop moving the movable measurement wire, and transmit the data of the depth at which it is inserted into the circular tube, that is, the liquid film thickness data, to the terminal; S3. Obtain the liquid film thickness data of a plurality of the probes in sequence according to S2, and fit the thickness distribution function of the circumferential liquid film of the annular flow in the circular tube according to the liquid film thickness data of the plurality of probes; S4. Adjust the inclination angle between the circular tube and the ground, and adjust the included angle between the circular tube and the ground to a new preset angle; repeat steps S1-S3 to obtain the phase interface characteristics of the annular flow in the circular tube at different inclination angles in sequence. The phase interface characteristics of the annular flow in the circular tube include the circumferential liquid film thickness distribution of the annular flow in the circular tube at different inclination angles.

[0015] Furthermore, the method further includes: S5. The method further includes: conveying the liquid droplets in the circular tube after the test to a liquid droplet measurement device for further gas-liquid separation, and separately collecting the separated liquid film and the core liquid droplets.

[0016] An analysis device and method for the phase interface characteristics of annular flow in a circular pipe under inclined conditions provided by the present invention accurately measure phase interface characteristics such as liquid film thickness. By arranging multiple groups of liquid film thickness measurement points on the inner peripheral wall of the circular pipe and using a probe including a fixed measurement wire and a movable measurement wire, the liquid film thickness of the annular flow in the circular pipe can be accurately measured, providing key data for in-depth study of the phase interface characteristics of annular flow. In the present application, the circular pipe can be arbitrarily adjusted with respect to the ground angle in space, meeting the experimental requirements at different inclination angles, thereby obtaining the phase interface characteristics of the annular flow in the circular pipe at different inclination angles, which helps to comprehensively understand the flow law of annular flow under different inclined conditions. In addition, the structure of the analysis device in the present application is reasonably designed, and the cooperation between components is tight, enabling stable and reliable operation. At the same time, the operation process is clear, facilitating the operation of experimental personnel and the acquisition of experimental data. The present application accurately obtains the phase interface characteristic data of annular flow at different inclination angles, which helps to deeply understand the flow characteristics of annular flow, providing a scientific basis for the optimal design of industrial processes in fields such as oil extraction, chemical processes, and nuclear energy utilization, and improving the efficiency and safety of industrial processes.

[0017] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented in accordance with the content of the description. And in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the specific embodiments of the present application are specifically given below. Brief Description of the Drawings

[0018] The drawings, as a part of the present invention, are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention, but do not constitute an improper limitation to the present invention. Obviously, the drawings in the following description are only some embodiments, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] In the drawings: Figure 1 shows a schematic structural diagram of an analysis device for the phase interface characteristics of annular flow in a circular pipe under inclined conditions provided by an embodiment of the present invention; Figure 2 shows a partial structural diagram of an analysis device for the phase interface characteristics of annular flow in a circular pipe under inclined conditions provided by an embodiment of the present invention; Figure 3 shows another partial structural diagram of an analysis device for the phase interface characteristics of annular flow in a circular pipe under inclined conditions provided by an embodiment of the present invention; Figure 4 shows a flowchart of an analysis method for the phase interface characteristics of annular flow in a circular pipe under inclined conditions provided by an embodiment of the present invention.

[0020] Reference Numerals in the Drawings 1. Round tube; 11. Probe; 2. Liquid film thickness measurement point; 3. Air compressor; 4. Water tank; 41. Pump; 5. Liquid flowmeter; 6. Flow control valve; 7. Gas flowmeter; 8. Flow pattern control valve; 9. Liquid droplet measurement device; 91. Liquid film collection container; 92. Leakage flow pipe; 93. Gas core liquid droplet collection container; 94. Connecting pipe; 941. First pipeline; 942. Second pipeline; 10. Discharge pipe; 101. Gas-water separator.

[0021] It should be noted that these drawings and textual descriptions are not intended to limit the scope of the concept of the present invention in any way, but to illustrate the concept of the present invention to those skilled in the art by referring to specific embodiments. Detailed implementation manners

[0022] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0023] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0024] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] Embodiment 1 As Figures 1-3As shown in the figure, an analysis device for the characteristics of the annular flow phase interface in a circular tube under inclined conditions includes: a circular tube 1, which is the core component of the entire analysis device and has the function of arbitrarily adjusting the angle with the ground in space, and can simulate the working conditions of the circular tube at different inclined angles, so as to study the influence of inclined conditions on the characteristics of the annular flow phase interface. At least two groups of liquid film thickness measurement points 2 are evenly arranged on the inner peripheral wall of the circular tube along the annular direction, and these measurement points provide the basic positions for subsequent measurement of the liquid film thickness; a probe 11, including a fixed measurement wire and a movable measurement wire, and the probe 11 is used to measure the liquid film thickness in the circumferential direction of the annular flow on the inner wall of the circular tube 1. Specifically, the fixed measurement wire is fixed, and the movable measurement wire can move. During the experiment, the fixed measurement wire and the movable measurement wire are arranged close to the inner wall of the circular tube 1, and the movable measurement wire is moved step by step. By continuously measuring the potential difference between the fixed measurement wire and the movable measurement wire until the potential difference between the movable measurement wire and the fixed measurement wire drops to zero, stop moving the movable measurement wire, and read the insertion depth of the movable wire at this moment, which is the thickness of the liquid film; a gas-liquid supply device for providing annular flow into the circular tube 1.

[0026] In this embodiment, the gas-liquid supply device includes: a water tank 4 for providing a solution into the circular tube 1. Preferably, the solution in the water tank 4 uses a potassium chloride solution with a concentration of 1000 PPM as the liquid-phase working medium; an air compressor 3 for providing a gas source into the circular tube 1; a pump 41 is provided between the water tank 4 and the circular tube 1, and a variable-frequency metering pump is selected and connected to the water tank 4 to inject the solution in the water tank 4 into the circular tube 1. Downstream of the pump 41, there is provided: a liquid flowmeter 5 for adjusting the liquid-phase flow rate entering the circular tube 1; a flow control valve 6 for jointly adjusting the liquid-phase flow rate entering the circular tube 1 with the pump 41.

[0027] In a feasible embodiment, a gas flowmeter 7 and a flow pattern control valve 8 are provided between the air compressor 3 and the circular tube 1; the flow pattern control valve 8 obtains the gas-phase flow rate required for the occurrence of annular flow according to the liquid-phase flow rate, and adjusts the flow rate of the air compressor 3 to a preset annular flow rate. During the experiment, after the liquid-phase flow rate entering the circular tube 1 is determined, the flow pattern control valve 8 calculates the gas-phase flow rate required for the occurrence of annular flow according to the liquid-phase flow rate, and automatically adjusts according to the gas-phase flow rate required for the occurrence of annular flow, so that annular flow meeting the experimental requirements appears in the circular tube 1. The liquid phase and the gas phase are mixed and enter the circular tube 1.

[0028] In this embodiment, the circular tube 1 is arranged to be vertical or inclined relative to the ground. Specifically, the inclination angle can be adjusted to 10°, 20°, 30°, 40°, 50°, 60°, 70°, and 80°. This multi-angle adjustment function can comprehensively study the influence of different inclination angles on the characteristics of the annular flow phase interface. Preferably, three layers of the liquid film thickness measurement points 2 are arranged in sequence along the liquid flow direction on the inner wall of the circular tube 1, and eight probes 11 are evenly arranged in the circumferential direction for each layer of the liquid film thickness measurement points 2 to measure the liquid film thickness in the circumferential direction of the annular flow in the circular tube in real time.

[0029] In a feasible embodiment, the analysis device further includes: a droplet measurement device 9 connected to the outlet end of the circular tube 1. The droplet measurement device 9 at least includes: a liquid film collection container 91 and a leakage tube 92. The leakage tube 92 leads the annular flow coming out of the circular tube 1 into the leakage tube 92. One end of the leakage tube 92 is connected to the liquid film collection container 91, and overflow holes are arranged on the inner wall of the leakage tube 92 near the circular tube 1, and the liquid of the liquid film enters the liquid film collection container 91 through the overflow holes.

[0030] In this embodiment, the droplet measurement device 9 further includes: a gas core droplet collection container 93 and a connecting pipe 94. The connecting pipe 94 includes a first pipe 941 and a second pipe 942, and there is an included angle in the vertical direction at the connection between the first pipe 941 and the second pipe 942. One end of the first pipe 941 is connected to the outlet of the leakage tube 92, and the second pipe 942 communicates with the gas core droplet collection container 93.

[0031] In a feasible embodiment, the analysis device further includes: a discharge pipe 10 that communicates with the connecting pipe 94 and the gas core droplet collection container 93 respectively. An air-water separator 101 is arranged inside the discharge pipe 10 for gas-liquid separation of the gas core.

[0032] In this embodiment, the diameter of the leakage tube 92 is the same as that of the circular tube 1, ensuring that the annular flow coming out of the circular tube 1 can smoothly and stably enter the leakage tube 92, reducing the influence of the pipe diameter change on the fluid flow state, making the collected liquid film and gas core droplets more truly reflect the actual situation of the annular flow in the circular tube, and improving the accuracy of the experimental results.

[0033] In this embodiment, a plurality of the probes 11 are evenly arranged in the circumferential direction for each group of the liquid film thickness measurement points 2, which can comprehensively and accurately measure the liquid film thickness at different positions in the circumferential direction of the annular flow in the circular tube 1, reduce the measurement error, improve the reliability of the liquid film thickness data, and thus more precisely analyze the thickness distribution of the liquid film in the circumferential direction of the annular flow in the circular tube 1.

[0034] Example 2 As Figure 4 As described in the flowchart of The method includes: S1. Start the analysis device, and supply gas-liquid two-phase fluid into the circular tube 1 through the pump 41, flow control valve 6, air compressor 3 and flow pattern control valve 8 to establish the annular flow required for the experiment; S2. When the potential difference between the movable measuring wire and the fixed measuring wire is adjusted to zero, stop moving the movable measuring wire, and transmit the depth data of the movable measuring wire inserted into the circular tube 1, that is, the liquid film thickness data, to the terminal; S3. According to the liquid film thickness data of multiple probes 11 obtained in S2, fit the thickness distribution function of the circumferential liquid film of the annular flow in the circular tube 1; S4. Adjust the inclination angle between the circular tube 1 and the ground, and adjust the included angle between the circular tube 1 and the ground to a new preset angle; repeat steps S1-S3 to obtain the phase interface characteristics of the annular flow in the circular tube 1 at different inclination angles. The phase interface characteristics of the annular flow in the circular tube include the circumferential liquid film thickness distribution of the annular flow in the circular tube at different inclination angles.

[0035] In a feasible implementation manner, the method further includes: S5. Gas-liquid separation and collection: Transport the liquid droplets in the circular tube 1 after the test to the liquid droplet measuring device 9 for further gas-liquid separation, and separately collect the separated liquid film and core liquid droplets.

[0036] The above is only a preferred embodiment of the present invention, and does not impose any form of limitation on the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art of this patent can make some changes or modifications to equivalent embodiments by using the technical content prompted above within the scope of the technical solution of the present invention. The implementation schemes in the above embodiments can also be further combined or replaced. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the present invention.

Claims

1. An analysis device for the phase interface characteristics of annular flow in a circular tube under inclined conditions, characterized in that, Comprising: A circular tube (1), the circular tube (1) can be arbitrarily adjusted in angle with the ground in space, and at least two groups of liquid film thickness measurement points (2) are uniformly arranged on the inner peripheral wall of the circular tube (1) along the opposite sides in the circumferential direction; A probe (11), including a fixed measurement wire and a movable measurement wire, the probe (11) is used to measure the liquid film thickness in the circumferential direction of the annular flow on the inner wall of the circular tube (1); A gas-liquid supply device, used to provide annular flow into the circular tube (1).

2. The device for analyzing the phase interface characteristics of annular flow in a circular tube under inclined conditions according to claim 1, characterized in that The gas-liquid supply device includes: a water tank (4), used to provide a solution into the circular tube (1); An air compressor (3), used to provide a gas source into the circular tube (1); A pump (41) is provided between the water tank (4) and the circular tube (1), and downstream of the pump (41) includes: a liquid flowmeter (5), used to adjust the liquid phase flow rate entering the circular tube (1); A flow control valve (6), jointly adjusting the liquid phase flow rate entering the circular tube (1) with the pump (41).

3. The device for analyzing the phase interface characteristics of annular flow in a circular tube under inclined conditions according to claim 2, characterized in that A gas flowmeter (7) and a flow pattern control valve (8) are provided between the air compressor (3) and the circular tube (1); The flow pattern control valve (8) obtains the gas phase flow rate required for annular flow according to the liquid phase flow rate, and adjusts the flow rate of the air compressor (3) to a preset annular flow rate.

4. The device for analyzing the phase interface characteristics of annular flow in a circular tube under inclined conditions according to claim 3, characterized in that The analysis device further includes: a droplet measurement device (9), connected to the outlet end of the circular tube (1); The droplet measurement device at least includes: a liquid film collection container (91), a leakage tube (92); For the leakage tube (92), the annular flow coming out of the circular tube (1) is introduced into the leakage tube (92), one end of the leakage tube (92) is connected to the liquid film collection container (91), and overflow holes are arranged on the inner wall of the leakage tube (92) near the circular tube (1), and the liquid of the liquid film enters the liquid film collection container (91) through the overflow holes.

5. The device for analyzing the phase interface characteristics of annular flow in a circular tube under inclined conditions according to claim 4, characterized in that The droplet measurement device further includes: a gas core droplet collection container (93), a connecting pipe (94); The connecting pipe (94) includes a first pipe (941) and a second pipe (942), and an angle is provided in the vertical direction at the connection of the first pipe (941) and the second pipe (942); One end of the first pipe (941) is connected to the outlet of the leakage tube (92), and the second pipe (942) is communicated with the gas core droplet collection container (93).

6. The device for analyzing the phase interface characteristics of annular flow in a circular tube under inclined conditions according to claim 5, characterized in that The analysis device further includes: a discharge pipe (10), which is respectively communicated with the connecting pipe (94) and the gas core droplet collection container (93); Inside the discharge pipe (10), there is a gas-liquid separator (101) for separating gas and liquid of the gas core.

7. The annular flow phase interface characteristic analysis device in a circular pipe under inclined conditions according to claim 6, wherein The diameter of the leakage pipe (92) is the same as that of the circular pipe (1).

8. The annular flow phase interface characteristic analysis device in a circular pipe under inclined conditions according to claim 1, wherein A plurality of the probes (11) are uniformly arranged along the circumferential direction for each group of the liquid film thickness measurement points (2).

9. A method for analyzing the interfacial characteristics of annular flow in a circular pipe under inclined conditions, characterized in that, The analysis method is implemented by using the analysis device described in any one of claims 1-8 above; The method includes: S1. Start the analysis device, supply gas-liquid two-phase fluid into the circular pipe (1) through the pump (41), flow control valve (6), air compressor (3) and flow pattern control valve (8), and establish the annular flow required for the experiment; S2. When the potential difference between the movable measurement wire and the fixed measurement wire is adjusted to zero, stop moving the movable measurement wire, and transmit the depth data of the movable measurement wire inserted into the circular pipe (1), that is, the liquid film thickness data, to the terminal; S3. According to the liquid film thickness data of a plurality of the probes (11) obtained successively in S2, and fit the thickness distribution function of the circumferential liquid film of the annular flow in the circular pipe (1) according to the liquid film thickness data of the plurality of the probes (11); S4. Adjust the inclination angle between the circular pipe (1) and the ground, and adjust the included angle between the circular pipe (1) and the ground to a new preset angle; repeat steps S1-S3 to obtain the phase interface characteristics of the annular flow in the circular pipe (1) at different inclination angles successively. The phase interface characteristics of the annular flow in the circular pipe include the circumferential liquid film thickness distribution of the annular flow in the circular pipe at different inclination angles.

10. The method for analyzing the phase interface characteristics of annular flow in a circular pipe under inclined conditions according to claim 9, wherein The method further includes: S5. Transport the liquid droplets in the circular pipe (1) after the test to a liquid droplet measurement device for further gas-liquid separation, and separately collect the separated liquid film and gas core liquid droplets.

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