Device for testing transportation characteristics of gas-liquid heavy metal interface

Abstract

The utility model provides a gas-liquid heavy metal interface transportation characteristic testing device, and belongs to the technical field of nuclear engineering. The gallium-indium-tin alloy which is in a liquid state at normal temperature is used as a liquid-phase working medium, so that the problems of high cost, toxicity, high power level and high risk of a traditional gas-liquid metal two-phase flow interface transport characteristic test device taking lead-bismuth alloy as a liquid-phase metal working medium are successfully solved; by using the gas storage bottle to switch helium and nitrogen as gas phase working media, the test can be carried out under two working conditions with great liquid-gas density ratio difference, and the influence mechanism of the density ratio effect on the interface transport characteristics can be deeply revealed.

Description

Technical Field

[0001] This utility model relates to the field of nuclear engineering technology, and in particular to a test device for the transport characteristics of gas-liquid heavy metal interfaces. Background Technology

[0002] In the field of nuclear engineering, lead-bismuth reactors have received widespread attention in recent years due to their high safety, sustainability, economic performance, and environmental friendliness. Under the condition of a steam generator heat transfer tube rupture accident in a lead-bismuth reactor, a steam-liquid heavy metal two-phase flow may occur in the reactor core. Furthermore, various light gas-liquid heavy metal two-phase flow conditions also occur in gas-lift enhanced natural circulation and in the molten core of a severe accident. The behavior of bubble generation, rising, and separation in the liquid metal directly affects heat transfer efficiency and flow resistance. In addition, bubble entrainment in the reactor core can lead to reactor power fluctuations. Therefore, it is crucial to study the interfacial transport characteristics of gas-liquid heavy metal two-phase flows.

[0003] In the past, experimental setups for studying the transport characteristics of gas-liquid two-phase flow interfaces of heavy metals have typically adopted the principle of proportional modeling, using lead-bismuth alloy as the liquid phase working medium and nitrogen as the gas phase working medium to build the experimental loop.

[0004] Lead-bismuth alloys have a high melting point, and the test circuit needs to operate at a high temperature. Therefore, the entire test circuit needs to be designed with a heater of considerable power and a test circuit insulation device. The test circuit is costly and has certain dangers. At the same time, the high operating temperature makes it difficult to carry out research on the interfacial transport characteristics of long-term continuous gas-liquid heavy metal two-phase flow.

[0005] Both lead and bismuth, components of lead-bismuth alloys, are toxic metals. Lead can cause neurotoxicity and kidney damage, while bismuth accumulation in the body may lead to neurological problems. Furthermore, because lead-bismuth alloys are used at relatively high operating temperatures, their volatility increases, making contact with or inhalation of their vapors or dust even more harmful to human health.

[0006] Previous experimental loops for gas-liquid heavy metal two-phase flow based on lead-bismuth alloys only used nitrogen as the gas phase working medium, which could not be used to carry out experimental research under various working conditions with large differences in liquid-gas density ratio. This limited the contribution to revealing the influence mechanism of density ratio effect on interfacial transport characteristics.

[0007] Therefore, it is necessary to design a room-temperature gas-liquid heavy metal two-phase flow test circuit that is low in melting point, low in cost, high in safety, and capable of studying various gas-liquid metal density ratios, in order to solve the above-mentioned technical problems. Utility Model Content

[0008] In view of this, the present invention aims to propose a test device for the transport characteristics of gas-liquid heavy metal interface. The room temperature gas-liquid heavy metal two-phase flow test loop design and test method have the characteristics of low melting point, low cost, high safety, and the ability to study various gas-liquid metal density ratios.

[0009] To achieve the above objectives, this utility model adopts the following technical solution: a gas-liquid heavy metal interface transport characteristic testing device, comprising:

[0010] The rising section is filled with a gallium indium tin liquid alloy and is equipped with an ultrasonic probe array for detecting and acquiring images of the liquid metal-gas two-phase flow and a pressure gauge for measuring the pressure of the liquid metal.

[0011] A gas generator is located inside the rising section at one end away from the liquid surface and connected to the gas supply assembly;

[0012] A conductivity probe is positioned at the end of the rising section away from the gas generator and is in contact with the gallium indium tin liquid alloy;

[0013] The descending section is connected to the ascending section via a liquid circulation section and a separation section, and the descending section, the separation section and the liquid circulation section are filled with gallium indium tin liquid alloy;

[0014] The liquid circulation section is located at the end of the rising section and the falling section away from the liquid surface, and the separation section is located at the end of the rising section and the falling section close to the liquid surface. The separation section is equipped with a one-way valve for replenishing potassium hydroxide.

[0015] A gas check valve is installed on the separation section.

[0016] Furthermore, the gas supply assembly includes a gas storage cylinder, which is connected to the gas generator.

[0017] Furthermore, a gas valve and a gas flow meter are provided between the gas storage cylinder and the gas generator.

[0018] Furthermore, the ultrasonic probe array has no fewer than two layers, and the line connecting the positions of two adjacent ultrasonic probes in the same layer to the center of the ultrasonic probe array is 45°, with the effective emission angle of each ultrasonic probe being no less than 45°.

[0019] Furthermore, the conductivity probe is mounted on an adjustable lead screw.

[0020] Furthermore, the descending section is equipped with a thermocouple and a heat exchanger.

[0021] Furthermore, the liquid circulation section is equipped with a fluid drive assembly, a liquid valve, and a liquid flow meter.

[0022] Furthermore, the material between the rising section, the separating section, the descending section, the liquid circulation section, and the connecting pipeline is polypropylene, and the cross-section is circular.

[0023] Furthermore, a filter screen is installed inside the liquid circulation section.

[0024] Beneficial effects:

[0025] 1. By using gallium indium tin alloy, which is liquid at room temperature, as the liquid working medium, the problems of high cost, toxicity, high power level, and high risk of traditional gas-liquid metal two-phase flow interface transport characteristics test devices that use lead bismuth alloy as the liquid working medium have been successfully overcome.

[0026] 2. By using gas storage cylinders to switch between helium and nitrogen as the gaseous working medium, experiments can be conducted under two types of working conditions with extremely different liquid-gas density ratios, which helps to reveal the mechanism of the influence of density ratio effect on interfacial transport characteristics.

[0027] 3. By using a two-layer ultrasonic probe array in the rising section, the position and morphology of bubbles can be determined by emitting ultrasonic waves and receiving their echo signals at the bubble interface in a gas-liquid heavy metal two-phase flow, and analyzing the signal's time delay and intensity changes. A reconstruction algorithm is then used to reconstruct a three-dimensional image of the bubbles based on two-dimensional information from multiple scanning sections, achieving high-fidelity visualization of bubble behavior in a gas-liquid heavy metal two-phase flow, thus enabling visualization of bubble behavior in opaque two-phase fluids.

[0028] 4. By arranging a conductivity probe that can change position at the upper end of the rising section, the conductivity probe can capture the level change signal caused by the passage of the gas-liquid interface based on the difference in conductivity between liquid heavy metal and gas. By organizing the signal according to the time sequence and then analyzing and calculating it according to the probe signal processing algorithm, high-precision synchronous measurement of interface parameters can be achieved.

[0029] 5. By fully considering the physical and chemical properties of liquid gallium indium tin alloy and using polypropylene as the pipe material, the wettability problem of gallium indium tin alloy to materials is effectively solved.

[0030] 6. By installing a one-way valve in the separation section and covering the liquid metal surface with a layer of potassium hydroxide solution of a certain concentration, the oxidation problem of gallium indium tin alloy can be mitigated.

[0031] 7. By using a fluid drive assembly to provide the drive head, the corrosion problem of gallium indium tin alloy can be avoided. Attached Figure Description

[0032] The accompanying drawings, which form part of this utility model, are used to provide a further understanding of the utility model. The illustrative embodiments of the utility model and their descriptions are used to explain the utility model and do not constitute an undue limitation of the utility model. In the drawings:

[0033] Figure 1 This is a schematic diagram of the structure of this utility model;

[0034] Figure 2 This is a top-view schematic diagram of the ultrasonic probe matrix of this utility model;

[0035] Figure 3 This is a schematic diagram of the conductivity probe of this utility model.

[0036] Circuit 1; Ultrasonic probe array 2; Conductivity probe 3; Adjustable lead screw 3-1; Bubble generator 4; Gas valve 5; Gas flow meter 6; Gas storage cylinder 7; Pressure gauge 8; Gas check valve 9; Thermocouple 10; Heat exchanger 11; Fluid drive assembly 12; Liquid valve 13; Liquid flow meter 14. Detailed Implementation

[0037] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present utility model can be combined with each other, and the described embodiments are only some embodiments of the present utility model, not all embodiments.

[0038] It should be noted that the descriptions of "left," "right," "left side," "right side," "upper part," "lower part," "top," and "bottom" in this utility model are defined based on the orientation or positional relationships shown in the accompanying drawings. They are used solely for the convenience of describing this utility model and for simplifying the description, and are not intended to indicate or imply that the described structure must be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In the description of this utility model, "multiple" means two or more, unless otherwise explicitly specified.

[0039] In the description of this utility model, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0040] Referring to the accompanying drawings, this embodiment describes a gas-liquid heavy metal interface transport characteristic testing device, comprising:

[0041] The rising section is filled with gallium indium tin liquid alloy and is equipped with an ultrasonic probe array 2 for detecting and acquiring images of the liquid metal-gas two-phase flow and a pressure gauge 8 for measuring the pressure of the liquid metal.

[0042] Gas generator 4 is located inside the rising section at one end away from the liquid surface and connected to the gas supply assembly;

[0043] The conductivity probe 3 is disposed at the end of the rising section away from the gas generator 4 and is in contact with the gallium indium tin liquid alloy;

[0044] The descending section is connected to the ascending section via a liquid circulation section and a separation section, and the descending section, the separation section and the liquid circulation section are filled with gallium indium tin liquid alloy;

[0045] The liquid circulation section is located at the end of the rising section and the falling section away from the liquid surface, and the separation section is located at the end of the rising section and the falling section close to the liquid surface. The separation section is equipped with a one-way valve for replenishing potassium hydroxide.

[0046] Gas check valve 9 is installed on the separation section;

[0047] The rising section, falling section, liquid circulation section, separation section, and rising section are connected in sequence to form loop 1.

[0048] After the gas-liquid metal two-phase flow in the rising section is separated in the separation section, the gas is discharged from the circuit through the gas check valve 9, which can maintain the stability of the circuit pressure.

[0049] A layer of potassium hydroxide solution of a certain concentration is placed over the separation section to prevent the liquid metal from oxidizing.

[0050] In this embodiment, the gas supply assembly includes a gas storage cylinder 7, which is connected to the gas generator 4. A gas valve 5 and a gas flow meter 6 are provided between the gas storage cylinder 7 and the gas generator 4. The gas inside the gas storage cylinder 7 is helium or nitrogen.

[0051] By monitoring the reading of the gas flow meter 6 and adjusting the opening of the gas valve 5, the bubble generation rate of the rising section bubble generator 4 can be controlled. By changing the type of gas in the gas storage cylinder 7, either helium or nitrogen, tests can be carried out under two working conditions with extremely large differences in liquid-gas density ratio.

[0052] In this embodiment, the ultrasonic probe array 2 has no less than two layers, and the line connecting the positions of two adjacent ultrasonic probes in the same layer to the center of the ultrasonic probe array is 45°. The effective emission angle of each ultrasonic probe is not less than 45°.

[0053] By using the ultrasonic probe array 2, an image of the rising liquid metal-gas two-phase flow can be obtained. By using the conductivity probe 3, the transport characteristics of the liquid metal-gas two-phase flow interface can be collected. The ultrasonic probe array has a two-layer structure with eight ultrasonic probes in each layer. The line connecting the positions of two adjacent ultrasonic probes in the same layer to the center of the ultrasonic probe array is 45°. The effective emission angle of each ultrasonic probe is not less than 45°. The entire interface can be sampled, and the image can be reconstructed on the host computer.

[0054] In this embodiment, the conductivity probe 3 includes an adjustable lead screw 3-1.

[0055] The conductivity probe 3 can adjust the sampling position of the probe in the liquid metal-gas two-phase flow through the lead screw structure 3-1 at the upper end of the probe, and perform sampling analysis on the liquid metal-gas two-phase flow under different mixing states.

[0056] In this embodiment, a thermocouple 10 and a heat exchanger 11 are provided on the descending section.

[0057] The descending section includes thermocouple 10 and heat exchanger 11. By monitoring the parameters of thermocouple 10 and adjusting the temperature and flow rate of the heat exchange fluid in heat exchanger 11, the liquid metal in the loop can be kept at a constant temperature.

[0058] In this embodiment, the liquid circulation section is provided with a fluid drive assembly 12, a liquid valve 13 and a liquid flow meter 14.

[0059] The liquid circulation section includes a fluid drive assembly 12, a liquid valve 13, and a liquid flow meter 14. The fluid drive assembly 12 is specifically a magnetic pump. Using the fluid drive assembly 12 can keep the liquid metal in the circuit in a circulating state, while avoiding corrosion of the pump body of the fluid drive assembly 12 by the liquid metal. The flow rate of the liquid metal in the circuit can be controlled by monitoring the parameters of the liquid flow meter 14 and adjusting the opening of the liquid valve 13.

[0060] In this embodiment, the material of the rising section, separating section, descending section, liquid circulation section and the connecting pipeline is polypropylene, and the cross-section is circular.

[0061] In this embodiment, a filter screen is provided inside the liquid circulation section.

[0062] A test method for the interfacial transport characteristics of a room-temperature gas-liquid heavy metal two-phase flow based on gallium indium tin alloy includes:

[0063] Check that all equipment is in normal working order;

[0064] Start the fluid drive assembly 12, monitor the value of the flow meter 14, monitor the value of the pressure gauge 8, and adjust the liquid metal flow rate to the required flow rate and pressure at the inlet of the rising section by adjusting the opening of the liquid valve 13;

[0065] Open gas valve 5, monitor the flow rate of gas flow meter 6, and adjust the gas flow rate to the required gas flow rate and pressure of bubble generator 4 by adjusting the opening of gas valve 5.

[0066] Start the heat exchanger 11, monitor the temperature of thermocouple 10 at the inlet of the descending section and the temperature at the inlet of the ascending section, and adjust the power of the heat exchanger 11 to bring the circulating liquid metal flowing into the ascending section to the required temperature.

[0067] Determine the liquid metal point that needs to be measured by the conductivity probe 3, and move the conductivity probe 3 to a suitable measurement point by adjusting the adjustable screw 3-1;

[0068] The experimental data collected by the ultrasonic probe array 2 and the conductivity probe 3 were analyzed to obtain the transport characteristics data of the gas-liquid metal two-phase flow interface, and the experiment ended.

[0069] Working principle:

[0070] Its startup and operation process is as follows:

[0071] Using a gallium-indium-tin alloy with low melting point and low toxicity as the liquid working medium facilitates low-cost testing of gas-liquid heavy metal two-phase flow under ambient temperature conditions. Using helium and nitrogen as the gas working medium allows for testing under two conditions with extremely large differences in liquid-gas density ratios (3.56×10⁴ and 5.08×10³, respectively), which helps to reveal the mechanism of the density ratio effect on interfacial transport characteristics. Gas is injected into the liquid inside the rising section through the gas storage cylinder 7 via the bubble generator 4. The fluid drive component 12 drives the liquid circulation, and the gas-filled liquid moves from bottom to top inside the rising section. By using a two-layer ultrasonic probe array 2 in the rising section, the echo signal of the bubble interface in the gas-liquid heavy metal two-phase flow can be received by emitting ultrasonic waves, and the position and morphology of the bubbles can be determined by analyzing the time delay and intensity changes of the signal. A reconstruction algorithm is used to reconstruct a three-dimensional image of the bubble based on two-dimensional information from multiple scanning sections. A position-adjustable conductivity probe 3, utilizing the conductivity difference between liquid heavy metals and gas, captures the level change signal caused by the passage of the gas-liquid interface. By organizing the signal according to a time sequence and then analyzing and calculating it using a probe signal processing algorithm, high-precision synchronous measurement of interface parameters can be achieved. Then, the liquid containing gas enters the separation section from the rising section for liquid-gas separation. The separated liquid is discharged from the circuit through a gas check valve 9, maintaining stable circuit pressure. Subsequently, the liquid that has discharged gas enters the descending section from the separation section. The liquid in the descending section undergoes temperature adjustment through a heat exchanger 11 before being transported back into the rising section by the fluid drive component 12.

[0072] High-fidelity visualization of bubble behavior in gas-liquid heavy metal two-phase flow is achieved, thus enabling visualization of bubble behavior in opaque two-phase fluids. Data such as temperature, pressure, flow rate, conductivity probe parameters, and ultrasonic probe matrix parameters are all input into a PC via the NI data acquisition system. Specialized programming software is used to acquire, calculate, display, and operate the experimental data, enabling real-time monitoring of the experimental conditions.

[0073] The sensors, controllers, and control programs mentioned above are all existing technologies and will not be elaborated upon.

[0074] The embodiments of the present invention disclosed above are merely illustrative of the present invention. The embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention.

Claims

1. A test apparatus for the transport characteristics of gas-liquid heavy metal interfaces, characterized in that, include: The rising section is filled with gallium indium tin liquid alloy and is equipped with an ultrasonic probe array (2) for detecting and acquiring images of liquid metal-gas two-phase flow and a pressure gauge (8) for measuring the pressure of liquid metal. A gas generator (4) is located inside the rising section at one end away from the liquid surface and is connected to the gas supply assembly; A conductivity probe (3) is disposed at one end of the rising section away from the gas generator (4) and is in contact with the gallium indium tin liquid alloy; The descending section is connected to the ascending section via a liquid circulation section and a separation section, and the descending section, the separation section and the liquid circulation section are filled with gallium indium tin liquid alloy; The liquid circulation section is located at the end of the rising section and the falling section away from the liquid surface, and the separation section is located at the end of the rising section and the falling section close to the liquid surface. The separation section is equipped with a one-way valve for replenishing potassium hydroxide. A gas check valve (9) is installed on the separation section.

2. The gas-liquid heavy metal interface transport characteristic test device according to claim 1, characterized in that: The gas supply assembly includes a gas storage cylinder (7), which is connected to the gas generator (4).

3. The gas-liquid heavy metal interface transport characteristic test device according to claim 2, characterized in that: A gas valve (5) and a gas flow meter (6) are provided between the gas storage cylinder (7) and the gas generator (4).

4. A gas-liquid heavy metal interface transport characteristic testing device according to claim 2 or 3, characterized in that, The gas inside the gas storage cylinder (7) is helium or nitrogen.

5. A gas-liquid heavy metal interface transport characteristic testing device according to claim 1, 2 or 3, characterized in that: The ultrasonic probe array (2) has at least two layers. The line connecting the positions of two adjacent ultrasonic probes in the same layer to the center of the ultrasonic probe array is 45°. The effective emission angle of each ultrasonic probe is not less than 45°.

6. The gas-liquid heavy metal interface transport characteristic test device according to claim 5, characterized in that: The conductivity probe (3) includes an adjustable lead screw (3-1).

7. The gas-liquid heavy metal interface transport characteristic testing device according to claim 6, characterized in that, The descending section is equipped with a thermocouple (10) and a heat exchanger (11).

8. The gas-liquid heavy metal interface transport characteristic test device according to claim 7, characterized in that: The liquid circulation section is equipped with a fluid drive assembly (12), a liquid valve (13), and a liquid flow meter (14).

9. The gas-liquid heavy metal interface transport characteristic testing device according to claim 4, characterized in that, The rising section, separating section, descending section, liquid circulation section, and connecting pipelines are made of polypropylene with a circular cross-section.

10. The gas-liquid heavy metal interface transport characteristic testing device according to claim 9, characterized in that, The liquid circulation section is equipped with a filter screen.

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