Gas injection device, gas-liquid two-phase flow experiment measurement system and measurement method

Abstract

The invention discloses a gas injection device, a gas-liquid two-phase flow experimental measurement system and a gas-liquid two-phase flow experimental measurement method. The air storage box is arranged on the bracket; the air inlet pipe is arranged on the bottom side of the air storage box and one end communicates with the interior of the air storage box; and the multiple anti-backflow nozzles are distributed on the top side of the gas storage box in an array mode, and one end of each anti-backflow nozzle communicates with the interior of the gas storage box. According to the gas injection device, when the gas injection device is applied to a gas-liquid two-phase flow experiment device, a plurality of bubble flows generated by the anti-backflow gas nozzles can form mutually disturbed convection fields, bubbles are promoted to be uniformly mixed in liquid metal, and when the bubbles of the adjacent anti-backflow gas nozzles rise, the surrounding liquid metal can be driven to form local circulation, so that the gas injection device can be used for gas-liquid two-phase flow experiment. After the circulation is overlapped, the bubbles can be pushed to a farther area, so that the bubbles can be uniformly distributed in the experimental device, and researchers can accurately measure related experimental parameters of the migration characteristics of the bubbles in the liquid metal in the experimental device.

Description

Technical Field

[0001] This invention relates to the field of nuclear energy engineering technology, and in particular to a gas injection device, a gas-liquid two-phase flow experimental measurement system, and a measurement method. Background Technology

[0002] In gas-liquid two-phase flow experimental devices, the commonly used gas injection method for the test tank is to open a simple gas injection port on one side of the test tank. For example, in a measurement device for gas jets in a two-phase flow environment with patent number CN115406943A, the gas injection port is located on the lower side of the rectangular water tank. This method of injecting gas through the gas injection port has the following drawbacks: When the above-mentioned gas injection method is applied to the experimental apparatus for two-phase flow of inert gas and liquid lead-bismuth, the high density and high viscosity of the liquid metal (lead-bismuth alloy) in the test vessel will restrict the diffusion of the injected bubbles at the gas injection port. The bubbles tend to concentrate near the gas injection port and form local accumulation, resulting in uneven distribution of bubbles in the test vessel. This makes it impossible for researchers to accurately measure the relevant experimental parameters of bubble migration characteristics in the liquid metal.

[0003] Therefore, the existing technology still needs to be improved and enhanced. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a gas injection device, which aims to solve the problem that the gas-liquid two-phase flow experimental device in the prior art, by injecting gas through the gas injection port, causes uneven distribution of bubbles in the test tank, resulting in researchers being unable to accurately measure the relevant experimental parameters of bubble migration characteristics in liquid metal.

[0005] The technical solution adopted by this invention to solve the technical problem is as follows: In a first aspect, embodiments of the present invention provide a gas injection device, comprising: support; A gas storage box, which is mounted on the bracket; An air intake pipe is provided on the bottom side of the air storage box and one end is connected to the interior of the air storage box. The anti-backflow nozzles are provided in multiples, and each anti-backflow nozzle is arranged in an array on the top side of the gas storage box, and one end of each anti-backflow nozzle is connected to the interior of the gas storage box.

[0006] As a further improved technical solution, the gas storage box includes: The box body has its bottom side mounted on the support, and its top side has an opening. One end of the air intake pipe is connected to and communicates with the box body. A cover is detachably disposed on the top side of the box to seal the opening of the box. Each of the anti-backflow nozzles is arranged in an array on the cover, and one end of each of the anti-backflow nozzles penetrates the cover and extends into the box.

[0007] As a further improvement, the above-mentioned gas injection device also includes: The housing and the cover are detachably connected by fixing screws.

[0008] Secondly, embodiments of the present invention also provide a gas-liquid two-phase flow experimental measurement system, which includes a gas injection device as described in any one of the above-mentioned methods, and further includes: The test section is equipped with a liquid metal inlet and outlet, the gas injection device is located at the bottom of the test section, the anti-backflow nozzle has one end that sprays bubbles facing the top of the test section, and the air inlet pipe passes through the bottom of the test section to introduce gas; A conductivity probe assembly, wherein the probe end of the conductivity probe assembly is disposed within the test section, and is used to measure the local cavitation fraction, interface area concentration and bubble frequency within the test section.

[0009] As a further improvement, the above-mentioned gas-liquid two-phase flow experimental measurement system also includes: A differential pressure measurement component has a first measuring end and a second measuring end, which are respectively set at different height positions within the test section, and are used to measure the average cavitation fraction between the first measuring end and the second measuring end.

[0010] As a further improved technical solution, the conductivity probe assembly includes a plurality of conductivity probes and a display panel. The detection ends of each conductivity probe are arranged in rows and spaced apart along the height direction of the test section, and the other end of each conductivity probe is electrically connected to the display panel.

[0011] As a further improvement, the above-mentioned gas-liquid two-phase flow experimental measurement system also includes: High-pressure gas cylinders; A gas transmission pipeline, the two ends of which are respectively connected to the high-pressure gas cylinder and the gas inlet pipe.

[0012] As a further improvement, the above-mentioned gas-liquid two-phase flow experimental measurement system also includes: The first gas valve is located on one end of the gas pipeline near the high-pressure gas cylinder; The second air valve is located at one end of the gas supply pipe near the air inlet pipe.

[0013] As a further improvement, the above-mentioned gas-liquid two-phase flow experimental measurement system also includes: A gas mass flow meter is installed on the gas pipeline and located between the second gas valve and the inlet pipe, for measuring the mass of gas entering the inlet pipe per unit time.

[0014] Thirdly, embodiments of the present invention also provide a measurement method applied to the above-mentioned gas-liquid two-phase flow experimental measurement system, which includes the following steps: Before the gas injection begins, close the first gas valve and the second gas valve, evacuate the interior of the test section to make it hollow, heat the liquid metal stored in the storage tank to the target temperature required for the experiment, and at the same time preheat the liquid delivery pipeline used to transport the liquid metal to the heat preservation temperature required for the experiment and keep it warm to prevent the liquid metal from condensing and solidifying in the liquid delivery pipeline. When the gas injection begins, open the liquid metal inlet / outlet on the test section, and inject the heated liquid metal in the storage tank into the test section through the liquid delivery pipeline until the liquid metal level in the test section reaches the preset position. Then, close the liquid metal inlet / outlet, adjust the test section to keep the liquid metal in the test section warm and maintain the target temperature required for the experiment, and at the same time open the first gas valve and the second gas valve to input the gas in the high-pressure gas cylinder into the test section. During the gas injection process, the air intake flow rate of the air intake pipe is controlled by adjusting the first gas valve and the second gas valve. The average cavitation fraction of the liquid metal two-phase flow in the measurement section under the current working condition is measured in real time by the differential pressure measurement component. The cavitation fraction, interface area concentration and bubble frequency of the cross section at different heights in the test section under the current working condition are measured in real time by the conductivity probe component. After the measurement is completed, open the liquid metal inlet and outlet on the test section to allow the high-pressure gas cylinder and the gas delivery pipeline to continue supplying gas into the test section until all the liquid metal in the test section is discharged. Then, close the first gas valve and the second gas valve, stop the insulation of the test section and the liquid delivery pipeline, and end the measurement experiment.

[0015] Compared with the prior art, the embodiments of the present invention have the following advantages: This invention provides a gas injection device, comprising: a support; a gas storage box disposed on the support; an air inlet pipe disposed on the bottom side of the gas storage box and having one end connected to the interior of the gas storage box; and multiple anti-backflow nozzles arranged in an array on the top side of the gas storage box, with one end of each anti-backflow nozzle connected to the interior of the gas storage box. In this invention, when the gas injection device is applied to a gas-liquid two-phase flow experimental apparatus, the multiple streams of bubbles generated by the arrayed anti-backflow nozzles on the gas storage box can form a mutually disturbing convection field, promoting uniform mixing of bubbles in the liquid metal. When bubbles rise from adjacent anti-backflow nozzles, they drive the surrounding liquid metal to form local circulation. These circulations, when superimposed, can push the bubbles to a more distant area, reducing aggregation caused by the unidirectional movement of bubble buoyancy. This allows the bubbles to be uniformly distributed in the experimental apparatus, facilitating researchers to accurately measure relevant experimental parameters regarding the bubble migration characteristics in the liquid metal. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural diagram of an air injection device provided by the present invention; Figure 2 This is a schematic diagram of the first embodiment of the cover in this invention; Figure 3 This is a schematic diagram of the second embodiment of the cover in this invention; Figure 4 A schematic diagram of the structure of an experimental measurement system for gas-liquid two-phase flow provided by the present invention; Figure 5 The flowchart of a measurement method for the above-mentioned gas-liquid two-phase flow experimental measurement system is provided by the present invention.

[0017] In the diagram: 1. Bracket; 2. Gas storage box; 201. Box body; 202. Cover; 3. Inlet pipe; 4. Anti-backflow nozzle; 5. Fixing screw; 6. Test section; 601. Liquid metal inlet / outlet; 701. Conductivity probe; 702. Display panel; 8. Differential pressure measurement assembly; 801. First measuring end; 802. Second measuring end; 9. High-pressure gas cylinder; 10. Gas pipeline; 11. First gas valve; 12. Second gas valve; 13. Gas mass flow meter. Detailed Implementation

[0018] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0019] Currently, in studying gas-liquid two-phase flow experiments, the common gas injection method is to inject gas through an injection port or by inserting a gas tube into the experimental device. However, when these methods are applied to an inert gas and liquid lead-bismuth two-phase flow experimental device, the high density and viscosity of the liquid metal (lead-bismuth alloy) in the test vessel restrict the diffusion of the injected bubbles at the injection port. This causes the bubbles to concentrate near the injection port, forming localized accumulations and resulting in uneven bubble distribution within the test vessel. Consequently, researchers are unable to accurately measure experimental parameters related to the bubble migration characteristics in the liquid metal. There are few existing gas injection devices specifically designed for gas-liquid two-phase flow experiments. Therefore, this invention provides the following embodiment to solve the above-mentioned technical problems.

[0020] Example 1: Please see Figures 1-3 The gas injection device includes: a support 1; a gas storage box 2, which is mounted on the support 1; an air inlet pipe 3, which is located on the bottom side of the gas storage box 2 and has one end connected to the interior of the gas storage box 2; and multiple anti-backflow nozzles 4, which are arranged in an array on the top side of the gas storage box 2 and have one end connected to the interior of the gas storage box 2.

[0021] like Figure 1 As shown, in this embodiment, the gas injection device includes a support 1, a gas storage box 2, an air inlet pipe 3, and an anti-backflow nozzle 4; wherein, the support 1, the gas storage box 2, the air inlet pipe 3, and the anti-backflow nozzle 4 are all made of metal. The support 1 can be a multi-legged support 1 such as a tripod 1 or a quadruped 1. The gas storage box 2 is disposed at the top of the support 1, and the gas storage box 2 and the top of the support 1 can be welded and fixed or detachably connected by bolts. The gas storage box 2 has a chamber for storing a certain amount of gas. The top end of the air inlet pipe 3 is connected to and communicates with the bottom side of the gas storage box 2. The air inlet pipe 3 is used to input external gas into the gas storage box 2. Multiple anti-backflow nozzles 4 are provided, and each anti-backflow nozzle 4 is arranged in an array on the top side of the gas storage box 2. The spacing between any two adjacent anti-backflow nozzles 4 is uniform. The bottom end of each anti-backflow nozzle 4 is connected to the interior of the gas storage box 2. The top ends of each anti-backflow nozzle 4 are at the same height and are parallel to each other, meaning the direction of the ejected bubbles is consistent. The anti-backflow nozzle 4 is a key component for realizing gas injection and forming a two-phase flow. The small inner diameter of the anti-backflow nozzle 4 allows the inert gas in the gas storage box 2 to be ejected into the liquid metal in the form of fine bubbles, forming a stable gas-liquid two-phase flow. The small inner diameter prevents the liquid metal from flowing back into the gas storage box 2, ensuring the unidirectionality of the gas injection process.

[0022] In this invention, when the gas injection device is applied to a gas-liquid two-phase flow experimental device, the multiple streams of bubbles generated by the anti-backflow jet nozzles arranged in an array on the gas storage box 2 can form a mutually disturbing convection field, promoting the uniform mixing of bubbles in the liquid metal. When the bubbles of adjacent anti-backflow jet nozzles rise, they will drive the surrounding liquid metal to form a local circulation. After these circulations are superimposed, they can push the bubbles to a more distant area, reducing the aggregation caused by the unidirectional movement of bubble buoyancy. This allows the bubbles to be evenly distributed in the experimental device, which is beneficial for researchers to accurately measure the relevant experimental parameters of bubble migration characteristics in the liquid metal in the experimental device.

[0023] The anti-backflow nozzle 4 has a relatively small inner diameter. When the inert gas is ejected from the gas storage box 2 through the anti-backflow nozzle 4, the small inner diameter creates a relatively large airflow resistance, causing the inert gas to be ejected at a higher speed. This generates sufficient pressure at the outlet of the anti-backflow nozzle 4 to prevent the liquid metal from flowing back. In addition, the smaller inner diameter of the anti-backflow nozzle 4 facilitates the control of bubble morphology.

[0024] Meanwhile, the gas storage box 2 serves as a temporary storage space for inert gas. The inert gas from the air inlet pipe 3 first enters the gas storage box 2 for storage, providing a basis for subsequent stable gas injection. The gas is evenly distributed to each anti-backflow nozzle 4, so that the inert gas stored therein can be evenly ejected through the gas needle in the anti-backflow nozzle 4, thereby forming a uniform gas-liquid two-phase flow in the gas-liquid two-phase flow experimental device. This facilitates the subsequent measurement and research of relevant parameters of the gas-liquid two-phase flow, and works with the support 1 to achieve stable gas injection.

[0025] Furthermore, the gas storage box 2 includes a box body 201 and a cover 202. The bottom side of the box body 201 is disposed on the bracket 1, the top side of the box body 201 is open, and one end of the air inlet pipe 3 is connected to and communicates with the box body 201. The cover 202 is detachably mounted on the top side of the box 201 to seal the opening of the box 201. Each anti-backflow nozzle 4 is arranged in an array on the cover 202, with one end of each anti-backflow nozzle 4 penetrating the cover 202 and extending into the box 201. Specifically, the part of the cover 202 used to connect to the box 201 has a sealing gasket (not shown), such as a rubber gasket, to seal the top opening of the box 201. The cover 202 has multiple holes arranged in an array. The bottom end of each anti-backflow nozzle 4 corresponds to one of the holes and extends through the holes into the box 201. Each anti-backflow nozzle 4 can be detachably connected and fixed to the cover 202 by bolts.

[0026] Furthermore, the gas injection device also includes a fixing screw 5, through which the housing 201 and the cover 202 are detachably connected. Specifically, the gas injection device has a cover 202 with multiple holes of different numbers and different spacing between the holes for assembly with the housing 201, as detailed below. Figure 2 and Figure 3 The cover 202, which has a different number of holes or a different spacing between holes, can be equipped with a different number of anti-backflow nozzles 4 to simulate a variety of experimental conditions.

[0027] Liquid metal-cooled fast reactors (LFRs) using lead-bismuth eutectic alloy (LBE) as coolant possess inherent safety and sustainability advantages due to their superior thermal-hydraulic characteristics and neutronics performance. This reactor type typically employs a pool-type structure design. Its main loop system includes key components such as the reactor core, main circulation pumps, and steam generators (SGs) or main heat exchangers (PHXs). The SG / PHX, acting as a crucial link between the primary and secondary loops, consists of numerous heat transfer tube bundles responsible for heat exchange between the high-temperature, low-pressure LBE and the low-temperature, high-pressure secondary loop coolant. Due to the significant temperature and pressure differences between the primary and secondary loops, the heat transfer tubes are subjected to long-term mechanical stress, thermal stress, and corrosion and fluid vibration caused by high turbulence, posing a high risk of rupture. In the event of an SG / PHX heat transfer tube rupture accident, the high-pressure secondary loop coolant will be injected into the LBE pool, potentially forming a two-phase bubble flow. The migration behavior of these steam or non-condensable bubbles in the liquid metal can trigger a series of phenomena that threaten reactor safety. Accurately understanding the migration characteristics of bubbles in liquid metal is a crucial foundation for studying such accident scenarios. Therefore, the present invention also provides the following second embodiment to solve the above-mentioned technical problems.

[0028] Example 2: Please see Figure 4 This invention also provides a gas-liquid two-phase flow experimental measurement system, which includes a gas injection device as described in any one of the above embodiments, and further includes a test section 6 and a conductivity probe 701 assembly. The test section 6 is provided with a liquid metal inlet / outlet 601. The gas injection device is located at the bottom of the test section 6. One end of the anti-backflow nozzle 4 that ejects bubbles faces the top of the test section 6. The air inlet pipe 3 penetrates the bottom of the test section 6 to introduce gas. The detection end of the conductivity probe 701 assembly is located inside the test section 6 and is used to measure the local cavitation fraction, interfacial area concentration, and bubble frequency within the test section 6.

[0029] Specifically, the test section 6 is a test pipeline. The outer periphery of the test section 6 is equipped with electrically heated insulation cotton (not shown) for heating the test section 6. The conductivity probe 701 assembly is an existing conductivity probe 701 system. A liquid metal inlet / outlet is located on one side of the bottom of the test section 6 for injecting or discharging liquid metal. A gas injection device is located at the bottom of the test section 6 to introduce external inert gas. The anti-backflow nozzle 4 has one end facing the top of the test section 6 where it ejects bubbles. The air inlet pipe 3 penetrates the bottom of the test section 6 to introduce gas. The detection end of the conductivity probe 701 assembly is located within the test section 6 and is used to measure the local cavitation fraction, interfacial area concentration, and bubble frequency within the test section 6. This local area is the cross-section of the detection end of the conductivity probe 701 assembly within the test section 6.

[0030] Furthermore, the gas-liquid two-phase flow experimental measurement system also includes a differential pressure measurement component 8. The differential pressure measurement component 8 has a first measuring end 801 and a second measuring end 802. The first measuring end 801 and the second measuring end 802 are respectively located at different heights within the test section 6, and are used to measure the average cavitation fraction between the first measuring end 801 and the second measuring end 802. Specifically, the first measuring end 801 and the second measuring end 802 can be flexibly set at different heights in the test section 6, such as the upper and lower sections of a vertical pipe or the high and low ends of an inclined pipe, to expand the measurement range of the cavitation fraction. Here, both vertical pipes and inclined pipes are implementations of the test section 6.

[0031] Furthermore, the conductivity probe 701 assembly includes a plurality of conductivity probes 701 and a display panel 702. The detection ends of each conductivity probe 701 are arranged in rows along the height direction of the test section 6 and spaced apart. The other end of each conductivity probe 701 is electrically connected to the display panel 702. Specifically, the conductivity probes 701 can be 3, 4, 5, etc. In this embodiment, there are 3 conductivity probes 701. The 3 conductivity probes 701 are arranged vertically in a row along the height direction of the test section 6 with uniform spacing. The highest conductivity probe 701 is aligned with the first measuring end 801, and the lowest conductivity probe 701 is aligned with the second measuring end 802. That is, the measurement range of the conductivity probe 701 assembly is consistent with the differential pressure measurement assembly 8. The data measured by the conductivity probes 701 will be displayed through the display panel 702. Three (or more) conductivity probes 701, evenly arranged along the height of the test section 6, can simultaneously collect the local cavitation fraction at different heights on the same vertical line of the test section 6 (such as the upper, middle, and lower parts of the vertical pipe). Compared with the differential pressure measurement component 8, which can only obtain the interval average cavitation fraction (overall average), the conductivity probe 701 component supplements the local details.

[0032] In this embodiment, the gas-liquid two-phase flow experimental measurement system further includes a high-pressure gas cylinder 9 and a gas delivery pipe 10; the two ends of the gas delivery pipe 10 are respectively connected to the high-pressure gas cylinder 9 and the inlet pipe 3. Specifically, the high-pressure gas cylinder 9 stores the inert gas required for the experiment, and the gas delivery pipe 10 is used to input the inert gas into the inlet pipe 3.

[0033] Furthermore, the gas-liquid two-phase flow experimental measurement system also includes a first gas valve 11 and a second gas valve 12. The first gas valve 11 is disposed on the end of the gas delivery pipeline 10 near the high-pressure gas cylinder 9, and the second gas valve 12 is disposed on the end of the gas delivery pipeline 10 near the inlet pipe 3. Both the first gas valve 11 and the second gas valve 12 are used to control the opening and closing of the gas delivery pipeline 10 or to regulate the gas flow rate within the gas delivery pipeline 10.

[0034] Furthermore, the gas-liquid two-phase flow experimental measurement system also includes a gas mass flow meter 13. The gas mass flow meter 13 is installed on the gas delivery pipe 10 and located between the second gas valve 12 and the inlet pipe 3. It is used to measure the mass of gas entering the inlet pipe 3 per unit time, providing direct basis for calculating relevant parameters of the gas-liquid two-phase flow. Simultaneously, a liquid mass flow meter is also installed on the pipe for the liquid metal inlet / outlet of the test section 6 to measure the mass of liquid metal entering the test section 6 per unit time.

[0035] Example 3: Please see Figure 5 This invention also provides a measurement method applied to the aforementioned gas-liquid two-phase flow experimental measurement system, comprising the following steps: Step S1: Before the gas injection begins, close the first gas valve and the second gas valve, evacuate the interior of the test section to form a hollow cavity, heat the liquid metal stored in the storage tank (not shown) to the target temperature required for the experiment, and at the same time preheat the liquid delivery pipeline (not shown) used to transport the liquid metal to the required insulation temperature for the experiment and keep it warm to prevent the liquid metal from condensing and solidifying in the liquid delivery pipeline. Specifically, after closing the first and second air valves, the test section is evacuated to a vacuum state. This thoroughly removes residual air, liquid, or impurities (such as liquid metal residue from the previous experiment or air bubbles adhering to the inner wall of the pipe) from the test section, avoiding interference from initial air bubbles. If residual air remains in the test section, it will mix with the introduced experimental gas after gas injection begins, causing the actual gas phase mass (measured by a gas mass flow meter) to differ from the true total gas phase volume in the test section, directly affecting the accuracy of the void fraction calculation. The physical properties of liquid metals (such as sodium and lead-bismuth alloys) (density, viscosity, surface tension, etc.) are extremely sensitive to temperature, and these properties directly affect the interaction between the gas and liquid phases, such as bubble formation, rising speed, and coalescence behavior. As the temperature increases, the viscosity of the liquid metal decreases, the flow resistance to the bubbles decreases, the rising speed increases, and the spatial distribution of the void fraction will be significantly different. For example, when the liquid metal is liquid lead-bismuth, the target temperature range for the experiment is 200-400℃, such as 250℃; the required insulation temperature range for the preheating experiment of the infusion pipeline is 150℃-200℃, such as 160℃. Furthermore, the heating method used for the infusion pipeline is to install electric heat tracing insulation cotton on its exterior.

[0036] Step S2: At the start of gas injection, open the liquid metal inlet / outlet on the test section, and inject the heated liquid metal from the storage tank into the test section through the inlet / outlet pipe until the liquid metal level in the test section reaches the preset position. Then, close the liquid metal inlet / outlet and adjust the test section to keep the liquid metal in the test section warm and maintain the target temperature required for the experiment. Heating of the test section is achieved through external electric heat tracing insulation cotton. For example, when the liquid metal is liquid lead-bismuth, the insulation temperature range of the test section is 200-400℃, such as keeping the liquid lead-bismuth at 250℃. Subsequently, open the first gas valve and the second gas valve to input the gas from the high-pressure gas cylinder into the test section. Step S3: During the gas injection process, the first and second gas valves are adjusted to control the air intake flow rate of the air intake pipe. The average cavitation fraction of the liquid metal two-phase flow in the measurement section under the current working condition is measured in real time by the differential pressure measurement component. The cavitation fraction, interfacial area concentration, and bubble frequency of the cross-section at different heights in the test section under the current working condition are measured in real time by the conductivity probe component. For example, by slowly changing the valve opening, the air intake flow rate is continuously changed from low to high (e.g., 0.1 kg / h → 1.0 kg / h) to simulate the gradual change of gas phase flow rate in industry. With the real-time measurement data, the continuous change curve of cavitation fraction with flow rate can be captured.

[0037] Step S4: After the measurement is completed, open the liquid metal inlet and outlet on the test section to allow the high-pressure gas cylinder and the gas delivery pipeline to continue supplying gas to the test section until all the liquid metal in the test section is discharged. Then, close the first gas valve and the second gas valve, stop the heat preservation of the test section and the liquid delivery pipeline, and end the measurement experiment.

[0038] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used 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. Therefore, they should not be construed as limitations on this invention.

[0039] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0040] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0042] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0043] Of course, the above description of the embodiments of the present invention is quite detailed, but it should not be construed as a limitation on the scope of protection of the present invention. The present invention may have many other implementations. Based on this implementation, other implementations obtained by those skilled in the art without any creative effort are all within the scope of protection of the present invention. The scope of protection of the present invention is determined by the appended claims.

Claims

1. A gas injection device, characterized in that, include: support; A gas storage box, which is mounted on the bracket; An air intake pipe is provided on the bottom side of the air storage box and one end is connected to the interior of the air storage box. The anti-backflow nozzles are provided in multiples, and each anti-backflow nozzle is arranged in an array on the top side of the gas storage box, and one end of each anti-backflow nozzle is connected to the interior of the gas storage box.

2. The gas injection device according to claim 1, characterized in that, The gas storage box includes: The box body has its bottom side mounted on the support, and its top side has an opening. One end of the air intake pipe is connected to and communicates with the box body. A cover is detachably disposed on the top side of the box to seal the opening of the box. Each of the anti-backflow nozzles is arranged in an array on the cover, and one end of each of the anti-backflow nozzles penetrates the cover and extends into the box.

3. The gas injection device according to claim 2, characterized in that, Also includes: The housing and the cover are detachably connected by fixing screws.

4. A gas-liquid two-phase flow experimental measurement system, characterized in that, The gas injection device as described in any one of claims 1-3 further includes: The test section is equipped with a liquid metal inlet and outlet, the gas injection device is located at the bottom of the test section, the anti-backflow nozzle has one end that sprays bubbles facing the top of the test section, and the air inlet pipe passes through the bottom of the test section to introduce gas; A conductivity probe assembly, wherein the probe end of the conductivity probe assembly is disposed within the test section, and is used to measure the local cavitation fraction, interface area concentration and bubble frequency within the test section.

5. The gas-liquid two-phase flow experimental measurement system according to claim 4, characterized in that, Also includes: A differential pressure measurement component has a first measuring end and a second measuring end, which are respectively set at different height positions within the test section, and are used to measure the average cavitation fraction between the first measuring end and the second measuring end.

6. The gas-liquid two-phase flow experimental measurement system according to claim 4, characterized in that, The conductivity probe assembly includes a plurality of conductivity probes and a display panel. The detection ends of each conductivity probe are arranged in rows and spaced apart along the height direction of the test section, and the other end of each conductivity probe is electrically connected to the display panel.

7. The gas-liquid two-phase flow experimental measurement system according to claim 4, characterized in that, Also includes: High-pressure gas cylinders; A gas transmission pipeline, the two ends of which are respectively connected to the high-pressure gas cylinder and the gas inlet pipe.

8. The gas-liquid two-phase flow experimental measurement system according to claim 7, characterized in that, Also includes: The first gas valve is located on one end of the gas pipeline near the high-pressure gas cylinder; The second air valve is located at one end of the gas supply pipe near the air inlet pipe.

9. The gas-liquid two-phase flow experimental measurement system according to claim 8, characterized in that, Also includes: A gas mass flow meter is installed on the gas pipeline and located between the second gas valve and the inlet pipe, for measuring the mass of gas entering the inlet pipe per unit time.

10. A measurement method applied to the gas-liquid two-phase flow experimental measurement system as described in claim 8 or 9, comprising the following steps: Before the gas injection begins, close the first gas valve and the second gas valve, evacuate the interior of the test section to make it hollow, heat the liquid metal stored in the storage tank to the target temperature required for the experiment, and at the same time preheat the liquid delivery pipeline used to transport the liquid metal to the heat preservation temperature required for the experiment and keep it warm to prevent the liquid metal from condensing and solidifying in the liquid delivery pipeline. When the gas injection begins, open the liquid metal inlet / outlet on the test section, and inject the heated liquid metal in the storage tank into the test section through the liquid delivery pipeline until the liquid metal level in the test section reaches the preset position. Then, close the liquid metal inlet / outlet, adjust the test section to keep the liquid metal in the test section warm and maintain the target temperature required for the experiment, and at the same time open the first gas valve and the second gas valve to input the gas in the high-pressure gas cylinder into the test section. During the gas injection process, the air intake flow rate of the air intake pipe is controlled by adjusting the first gas valve and the second gas valve. The average cavitation fraction of the liquid metal two-phase flow in the measurement section under the current working condition is measured in real time by the differential pressure measurement component. The cavitation fraction, interface area concentration and bubble frequency of the cross section at different heights in the test section under the current working condition are measured in real time by the conductivity probe component. After the measurement is completed, open the liquid metal inlet and outlet on the test section to allow the high-pressure gas cylinder and the gas delivery pipeline to continue supplying gas into the test section until all the liquid metal in the test section is discharged. Then, close the first gas valve and the second gas valve, stop the insulation of the test section and the liquid delivery pipeline, and end the measurement experiment.

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