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

Abstract

The invention provides a gas-liquid heavy metal interface transport characteristic test device and test method, 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] The invention relates to the technical field of nuclear engineering, and in particular to a gas-liquid heavy metal interface transport characteristic test device and test method. Background Art

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

[0003] In the past, experimental devices for studying the interfacial transport characteristics of gas-liquid heavy metal two-phase flows usually adopted the principle of proportional modeling, using lead-bismuth alloy as the liquid phase working fluid and nitrogen as the gas phase working fluid to build the experimental circuit.

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

[0005] Lead and bismuth are both toxic metals in the lead-bismuth alloy. Lead can cause neurotoxicity and kidney damage, while bismuth accumulation in the body may cause nervous system problems. And because lead-bismuth alloy is used at a higher temperature when the device is running, its volatility is enhanced, and contact or inhalation of its vapor or dust is more harmful to human health.

[0006] In the past, the gas-liquid heavy metal two-phase flow test loop based on lead-bismuth alloy only used nitrogen as the gas phase working fluid, which made it impossible to carry out experimental research under various working conditions with extremely different liquid-gas density ratios, and its contribution to revealing the research mechanism of the influence of density ratio effect on interfacial transport characteristics was limited.

[0007] Therefore, it is necessary to design a room-temperature gas-liquid heavy metal two-phase flow test circuit design and test method with low melting point, low cost, high safety, and the ability to study a variety of gas-liquid metal density ratios to solve the above technical problems. Summary of the invention

[0008] In view of this, the present invention aims to propose a gas-liquid heavy metal interface transport characteristics test device and test method. 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 can study a variety of gas-liquid metal density ratios.

[0009] To achieve the above object, the present invention adopts the following technical scheme. According to one aspect of the present invention, a gas-liquid heavy metal interface transport characteristics test device is provided, comprising:

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

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

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

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

[0014] Wherein, the liquid circulation section is arranged at the ends of the ascending section and the descending section away from the liquid surface, and the separation section is arranged at the ends of the ascending section and the descending section close to the liquid surface;

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

[0016] Furthermore, the gas supply assembly includes a gas storage bottle, and the gas storage bottle 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 ultrasound probe array has no less than two layers, the line between the arrangement positions of two adjacent ultrasound probes in the same layer and the center of the ultrasound probe array is 45 degrees, and the effective emission angle of each ultrasound probe is not less than 45 degrees.

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

[0020] Furthermore, a thermocouple and a heat exchanger are provided on the descending section.

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

[0022] Furthermore, the material of the ascending section, the separating section, the descending section, the liquid circulation section and the connecting pipelines is polypropylene, and the cross section is circular.

[0023] According to another aspect of the present invention, there is provided a method for testing the transport characteristics of a gas-liquid heavy metal interface, comprising:

[0024] Check whether each device is in normal working condition;

[0025] Start the fluid drive assembly, monitor the flow meter value, monitor the pressure gauge value, and adjust the liquid metal flow rate to the required flow rate and pressure at the entrance of the ascending section by adjusting the opening of the liquid valve;

[0026] Open the gas valve, monitor the flow rate of the gas flow meter, and adjust the gas flow rate to the gas flow rate and pressure required by the bubble generator by adjusting the opening of the gas valve;

[0027] Start the heat exchanger, monitor the thermocouple temperature 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 to make the circulating liquid metal flowing into the ascending section reach the required temperature;

[0028] Determine the liquid metal point that needs to be measured by the conductivity probe, and move the conductivity probe to a suitable measuring point by adjusting the adjustable screw;

[0029] The test data collected by the ultrasonic probe array and the conductivity probe were analyzed to obtain the gas-liquid metal two-phase flow interface transport characteristics data, and the test was completed.

[0030] Beneficial effects:

[0031] 1. By using gallium-indium-tin alloy, which is liquid at room temperature, as the liquid phase working fluid, the problems of high cost, toxicity, high power level and high danger of the traditional gas-liquid metal two-phase flow interface transport characteristics test device using lead-bismuth alloy as the liquid phase working fluid metal were successfully overcome.

[0032] 2. By using gas cylinders to switch between helium and nitrogen as the gas phase working fluid, experiments can be carried out under two types of working conditions with extremely different liquid-gas density ratios, which helps to further reveal the influence mechanism of density ratio effect on interfacial transport characteristics.

[0033] 3. By using a two-layer ultrasonic probe array in the ascending section, the position and shape of the bubble can be determined by emitting ultrasonic waves and receiving the echo signal of the bubble interface in the gas-liquid heavy metal two-phase flow, and analyzing the signal delay and intensity change. The reconstruction algorithm is used to restore the three-dimensional image of the bubble based on the two-dimensional information of multiple scanning sections, and the high-fidelity visualization of the bubble behavior in the gas-liquid heavy metal two-phase flow is realized, thereby achieving the visualization of the bubble behavior in the opaque two-phase fluid.

[0034] 4. By arranging a conductivity probe that can change its position at the upper end of the ascending 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 metals and gases. By arranging the signal in time series and then analyzing and calculating it based on the probe signal processing algorithm, high-precision synchronous measurement of interface parameters can be achieved.

[0035] 5. By fully considering the physical and chemical properties of liquid gallium indium tin alloy and using polypropylene as the pipeline material, the problem of the wettability of gallium indium tin alloy to the material is effectively solved.

[0036] 6. Avoid the corrosion problem of gallium indium tin alloy by using a fluid drive component to provide a driving pressure head. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0038] Figure 1 It is a schematic diagram of the structure of the present invention;

[0039] Figure 2 Schematic diagram of the top view of the ultrasound probe matrix of the present invention;

[0040] Figure 3 Schematic diagram of the conductivity probe of the present invention.

[0041] Loop 1; ultrasonic probe array 2; conductivity probe 3; adjustable screw 3-1; bubble generator 4; gas valve 5; gas flow meter 6; gas storage bottle 7; pressure gauge 8; gas check valve 9; thermocouple 10; heat exchanger 11; fluid drive component 12; liquid valve 13; liquid flow meter 14. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely explain the technical solutions in the embodiments of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict, and the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0043] It should be noted that the descriptions of the present invention regarding directions such as "left", "right", "left side", "right side", "upper", "lower", "top", and "bottom" are all defined based on the relationship between the orientations or positions shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the structure must be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention. In the description of the present invention, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0044] In the description of the present invention, unless otherwise clearly specified and limited, 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 direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] Referring to the accompanying drawings, this embodiment is described. According to one aspect of the present invention, there is provided a gas-liquid heavy metal interface transport characteristics test device, comprising:

[0046] The ascending section is filled with gallium-indium-tin liquid alloy and is provided with an ultrasonic probe array 2 for detecting and acquiring liquid metal-gas two-phase flow images and a pressure gauge 8 for measuring liquid metal pressure;

[0047] A gas generator 4 is arranged at one end of the rising section away from the liquid surface and connected to the gas supply assembly;

[0048] A conductivity probe 3 is arranged at one end of the ascending section away from the gas generator 4 and in contact with the gallium-indium-tin liquid alloy;

[0049] A descending section is connected to the ascending section through a liquid circulation section and a separation section, wherein the descending section, the separation section and the liquid circulation section are filled with gallium, indium and tin liquid alloy;

[0050] Wherein, the liquid circulation section is arranged at the ends of the ascending section and the descending section away from the liquid surface, and the separation section is arranged at the ends of the ascending section and the descending section close to the liquid surface;

[0051] A gas check valve 9, arranged on the separation section;

[0052] The ascending section, descending section, liquid circulation section, separation section and ascending section are sequentially connected to form a loop 1.

[0053] After the gas-liquid metal two-phase flow in the ascending section is separated in the separation section, the gas is discharged from the circuit through the gas check valve 9, which can maintain the circuit pressure stable.

[0054] A layer of potassium hydroxide solution of a certain concentration is covered above the separation section to prevent the liquid metal from oxidizing.

[0055] In this embodiment, the gas supply assembly includes a gas 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 cylinder 7 and the gas generator 4. The gas inside the gas cylinder 7 is helium or nitrogen.

[0056] The bubble generation rate of the ascending bubble generator 4 can be controlled by monitoring the reading of the gas flow meter 6 and adjusting the opening of the gas valve 5. By replacing the type of gas in the gas storage bottle 7 with helium or nitrogen, tests can be carried out under two types of working conditions with extremely different liquid-gas density ratios.

[0057] In this embodiment, the ultrasonic probe array 2 has no less than two layers, the line between the positions of two adjacent ultrasonic probes in the same layer and the center of the ultrasonic probe array is 45 degrees, and the effective emission angle of each ultrasonic probe is not less than 45 degrees.

[0058] By using the ultrasonic probe array 2, the image of the liquid metal-gas two-phase flow in the ascending section can be obtained, and by using the conductivity probe 3, the interface transport characteristics of the liquid metal-gas two-phase flow can be collected. The ultrasonic probe array has a two-layer structure, and the number of ultrasonic probes in each layer is 8. The line connecting the arrangement positions of two adjacent ultrasonic probes in the same layer and the center of the ultrasonic probe array is 45°. The effective emission angle of each ultrasonic probe is not less than 45°. The entire sampled interface can be sampled and the image can be reconstructed on the host computer.

[0059] In this embodiment, the conductivity probe 3 includes an adjustable screw rod 3 - 1 .

[0060] The conductivity probe 3 can adjust the sampling position of the probe in the liquid metal-gas two-phase flow through the screw structure 3-1 at the upper end of the probe, and perform sampling and analysis on the liquid metal-gas two-phase flow in different mixing states.

[0061] In this embodiment, a thermocouple 10 and a heat exchanger 11 are provided on the descending section.

[0062] The descending section includes a thermocouple 10 and a heat exchanger 11. By monitoring the parameters of the thermocouple 10 and adjusting the temperature and flow rate of the heat exchange fluid in the heat exchanger 11, the temperature of the liquid metal in the loop can be kept at a constant value.

[0063] In this embodiment, a fluid drive component 12, a liquid valve 13 and a liquid flow meter 14 are provided on the liquid circulation section.

[0064] The liquid circulation section includes a fluid drive component 12, a liquid valve 13, and a liquid flow meter 14. The fluid drive component 12 is specifically a magnetic pump. The use of the fluid drive component 12 can keep the liquid metal in the loop in a circulating state while preventing the pump body of the fluid drive component 12 from being corroded by the liquid metal. The flow rate of the liquid metal in the loop can be controlled by monitoring the parameters of the liquid flow meter 14 and adjusting the opening of the liquid valve 13.

[0065] In this embodiment, the material of the ascending section, the separating section, the descending section, the liquid circulation section and the connected pipelines is polypropylene, and the cross section is circular.

[0066] According to another aspect of the present invention, a method for testing the interface transport characteristics of a room temperature gas-liquid heavy metal two-phase flow based on a gallium-indium-tin alloy is provided, comprising:

[0067] Check whether each device is in normal working condition;

[0068] 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 entrance of the ascending section by adjusting the opening of the liquid valve 13;

[0069] Open the gas valve 5, monitor the flow rate of the gas flowmeter 6, and adjust the gas flow rate to the gas flow rate and pressure required by the bubble generator 4 by adjusting the opening of the gas valve 5;

[0070] Start the heat exchanger 11, monitor the temperature of the 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 make the circulating liquid metal flowing into the ascending section reach the required temperature;

[0071] 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 rod 3-1;

[0072] The test data collected by the ultrasonic probe array 2 and the conductivity probe 3 are analyzed to obtain the gas-liquid metal two-phase flow interface transport characteristic data, and the test is completed.

[0073] Working principle:

[0074] The startup and operation process is as follows:

[0075] Gallium-indium-tin alloy with low melting point and low toxicity is used as the liquid phase working fluid, which creates convenient conditions for low-cost implementation of gas-liquid heavy metal two-phase flow experiments under room temperature conditions; helium and nitrogen are used as gas phase working fluids, and experiments can be carried out under two types of working conditions with extremely different liquid-gas density ratios (3.56×104 and 5.08×103, respectively), which helps to deeply reveal the influence mechanism of density ratio effect on interface transport characteristics. The gas storage cylinder 7 injects gas into the liquid inside the ascending section through the bubble generator 4, and the fluid drive component 12 drives the liquid circulation. The gas-injected liquid moves from bottom to top inside the ascending section. By using a two-layer ultrasonic probe array 2 in the ascending section, ultrasonic waves can be emitted and received at the bubble interface in the gas-liquid heavy metal two-phase flow, and the signal delay and intensity change can be analyzed to determine the position and shape of the bubble. The reconstruction algorithm is used to restore the three-dimensional image of the bubble based on the two-dimensional information of the multi-scanning cross-sections. The conductivity probe 3 that can change its position is used to capture the level change signal caused by the passage of the gas-liquid interface according to the conductivity difference between the liquid heavy metal and the gas. By arranging the signal in time series and then analyzing and calculating according to the probe signal processing algorithm, high-precision synchronous measurement of the interface parameters can be achieved. Then the gas-filled liquid enters the separation section from the ascending section to separate the liquid and the gas. The separated liquid is discharged from the circuit through the gas check valve 9 to maintain the circuit pressure stable. Then the gas-discharging liquid enters the descending section from the separation section. The liquid entering the descending section is adjusted in temperature by the heat exchanger 11 and then transported back to the ascending section by the fluid drive component 12.

[0076] High-fidelity visualization of bubble behavior in gas-liquid heavy metal two-phase flow is achieved, thereby visualizing bubble behavior in opaque two-phase fluids. The temperature, pressure, flow, conductivity probe parameters, ultrasonic probe matrix parameters and other data in the test are input into the PC by the data acquisition system. Special programming software is used to collect, calculate, display and operate the test data to achieve real-time monitoring of the test conditions.

[0077] In the above description, the sensors, controllers, control programs, etc. that may be involved are all existing technologies and will not be described in detail.

[0078] The embodiments of the present invention disclosed above are only used to help illustrate the present invention. The embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. According to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well.

Claims

1. A gas-liquid heavy metal interface transport characteristics test device, characterized in that: include: The ascending section is filled with gallium-indium-tin liquid alloy and is provided with an ultrasonic probe array (2) for detecting and acquiring liquid metal-gas two-phase flow images and a pressure gauge (8) for measuring liquid metal pressure; A gas generator (4) is arranged at an end of the rising section away from the liquid surface and connected to the gas supply assembly; A conductivity probe (3) is arranged at one end of the ascending section away from the gas generator (4) and is in contact with the gallium-indium-tin liquid alloy; A descending section is connected to the ascending section through a liquid circulation section and a separation section, wherein the descending section, the separation section and the liquid circulation section are filled with gallium, indium and tin liquid alloy; Wherein, the liquid circulation section is arranged at the ends of the ascending section and the descending section away from the liquid surface, and the separation section is arranged at the ends of the ascending section and the descending section close to the liquid surface; A gas check valve (9) is arranged on the separation section.

2. A gas-liquid heavy metal interface transport characteristics test device according to claim 1, characterized in that: The gas supply assembly comprises a gas storage bottle (7), and the gas storage bottle (7) is connected to the gas generator (4).

3. A gas-liquid heavy metal interface transport characteristics 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 bottle (7) and the gas generator (4).

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

5. A gas-liquid heavy metal interface transport characteristics test device according to claim 1, 2 or 3, characterized in that: The ultrasonic probe array (2) has no less than two layers, the line between the arrangement positions of two adjacent ultrasonic probes in the same layer and the center of the ultrasonic probe array is 45 degrees, and the effective emission angle of each ultrasonic probe is no less than 45 degrees.

6. A gas-liquid heavy metal interface transport characteristics test device according to claim 5, characterized in that: The conductivity probe (3) is arranged on an adjustable screw rod (3-1).

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

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

9. A gas-liquid heavy metal interface transport characteristics test device according to claim 4, characterized in that: The ascending section, the separating section, the descending section, the liquid circulation section and the connecting pipelines are made of polypropylene, and the cross section is circular.

10. A method for testing the transport characteristics of a gas-liquid heavy metal interface, characterized in that: include: Check whether each device is in normal working condition; Start the fluid drive component (12), monitor the value of the flow meter (14), monitor the value of the pressure gauge (8), and adjust the flow rate of the liquid metal to the required flow rate and pressure at the entrance of the ascending section by adjusting the opening of the liquid valve (13); Open the gas valve (5), monitor the flow rate of the gas flow meter (6), and adjust the gas flow rate to the gas flow rate and pressure required by the bubble generator (4) by adjusting the opening of the gas valve (5); Starting the heat exchanger (11), monitoring the temperature of the thermocouple (10) at the inlet of the descending section and the temperature at the inlet of the ascending section, and adjusting the power of the heat exchanger (11) so that the circulating liquid metal flowing into the ascending section reaches the required temperature; Determine the point of the liquid metal 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); The test data collected by the ultrasonic probe array (2) and the conductivity probe (3) are analyzed to obtain the gas-liquid metal two-phase flow interface transport characteristic data, and the test is completed.

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