Aerosol deposition experimental apparatus and experimental method for simulating nuclear reactor accidents

Abstract

This application relates to an aerosol deposition experimental apparatus and method for simulating nuclear reactor accidents. The aerosol deposition experimental apparatus is used in experimental devices simulating nuclear reactor accidents. The apparatus includes an aerosol generator, an experimental container, an electric field generator, and auxiliary mechanisms. The aerosol generator generates aerosol particles; the experimental container has an internal containment cavity connected to the aerosol generator, allowing aerosol particles to enter; the electric field generator is mounted on the experimental container and can generate an electric field within the containment cavity; the auxiliary mechanisms work in conjunction with the electric field generator to perform thermophoresis and diffusion-coagulation experiments on the aerosol particles within the containment cavity, wherein the electric field force and gravity acting on the aerosol particles are balanced. This aerosol deposition experimental apparatus can perform thermophoresis or diffusion-coagulation experiments on aerosol particles, which helps in developing single-phase deposition mechanism models and more accurately measuring the amount of aerosol deposition.

Description

Technical Field

[0001] This application relates to the technical field of nuclear power plant facility maintenance, and in particular to an aerosol deposition experimental device and method for simulating nuclear reactor accidents. Background Technology

[0002] When a serious accident occurs at a nuclear power plant, radioactive fission products exist within the containment vessel in various forms, including gas, droplets, and aerosols. Aerosols, formed by radioactive fission products suspended in solid or droplet form within the gaseous space of the containment vessel, are the primary form of these products. If the pressure within the containment vessel exceeds its ultimate bearing capacity, it may lead to containment failure, releasing radioactive aerosols into the environment and causing pollution.

[0003] To mitigate safety threats under severe accidents, design mitigation measures, and develop computational models, a thorough understanding of aerosol migration mechanisms is necessary. In actual operation, aerosol migration is often a coupled process involving multiple migration mechanisms, which rarely occur independently. For example, gravity sedimentation is often accompanied by Brownian diffusion, thermophoretic deposition is often accompanied by gravity sedimentation, and diffusion electrophoresis is often accompanied by both thermophoresis and gravity sedimentation. Current experimental equipment cannot verify single-mechanism experiments; therefore, a single-mechanism experiment is urgently needed to accurately measure the amount of aerosol deposition. Summary of the Invention

[0004] This application addresses the problem of existing aerosol deposition experimental methods relying on single-mechanism experiments for verification. It proposes an aerosol deposition experimental device and method for simulating nuclear reactor accidents. This aerosol deposition experimental device and method can perform single-mechanism experiments to accurately measure the amount of aerosol deposition.

[0005] In a first aspect, embodiments of this application provide an aerosol deposition experimental apparatus for simulating nuclear reactor accidents, comprising:

[0006] Aerosol generator, used to generate aerosol particles;

[0007] The experimental container has an internal cavity that is connected to the aerosol generator and allows the aerosol particles to enter.

[0008] An electric field generator is installed on the experimental container and is capable of generating an electric field within the containment cavity;

[0009] An auxiliary mechanism, used in conjunction with the electric field generator, is used to conduct thermophoresis or diffusion-electrophoresis experiments on aerosol particles within the containment cavity, wherein the electric field force and gravity acting on the aerosol particles are balanced.

[0010] In one embodiment, the receiving cavity extends along a first direction, and the receiving cavity has a first cavity wall and a second cavity wall spaced apart along the first direction, the first cavity wall being in communication with the aerosol generator;

[0011] The auxiliary mechanism includes a heating element that extends along the first direction from the first cavity wall toward the second cavity wall, and the temperature of the heating element gradually decreases.

[0012] In one embodiment, the temperature gradient of the heating element is a, where 1000K / m < a < 4000K / m.

[0013] In one embodiment, the second cavity wall is provided with a sampling element for capturing the deposited aerosol particles. The auxiliary mechanism also includes a condenser, which is installed on and covers the second cavity wall. The sampling element is installed on the side of the condenser away from the second cavity wall, and the sampling element is detachably connected to the condenser.

[0014] In one embodiment, the auxiliary mechanism further includes a plurality of air supply components, all of which are spaced apart in the receiving cavity along the first direction, and the air supply components are used to supply air into the receiving cavity.

[0015] In one embodiment, the auxiliary mechanism further includes an air supply unit, a dryer, an air heater, and a steam generator. The dryer is connected between the air supply unit and the air heater. The air heater is connected to the receiving cavity. The steam generator is connected between the dryer and the air heater.

[0016] The air heater and the steam generator are selectively connected to the receiving cavity. When the air heater is connected to the receiving cavity, the thermophoresis experiment is performed; when the steam generator is selectively connected to the receiving cavity, the diffusion electrophoresis experiment is performed.

[0017] An aerosol deposition experimental method for simulating nuclear reactor accidents, employing the aerosol deposition experimental equipment described above, wherein the aerosol deposition experimental method includes:

[0018] Nitrogen gas is injected into the containing cavity of the experimental container;

[0019] Activate the air supply component of the auxiliary mechanism and inject aerosol particles into the containment cavity using an aerosol generator;

[0020] When the concentration of aerosol particles in the containment cavity reaches a preset value, the aerosol generator and the air supply component are turned off, and the electric field generator is turned on, so that the electric field force and gravity on the aerosol particles are balanced; the auxiliary mechanism works with the electric field generator to conduct thermophoresis or diffusion experiments on the aerosol particles.

[0021] In one embodiment, the auxiliary mechanism further includes a heating element and a gas supply element, and the auxiliary mechanism, in conjunction with the electric field generator, performs a thermophoresis experiment on the aerosol particles, including:

[0022] Before injecting nitrogen into the cavity of the experimental container, the cavity is heated by the heating element to create a temperature gradient inside the cavity.

[0023] When nitrogen is injected into the containment cavity of the experimental container, the nitrogen is injected into the containment cavity using the gas supply device. The nitrogen passes through a dryer and an air heater in sequence. When the nitrogen enters the containment cavity, the humidity inside the containment cavity is 0%.

[0024] In one embodiment, the auxiliary mechanism further includes an air supply unit, a dryer, and a steam generator. The auxiliary mechanism, in conjunction with the electric field generator, performs a diffusion-phoresis experiment on the aerosol particles, including:

[0025] When nitrogen is injected into the containment cavity of the experimental container, the nitrogen is injected into the containment cavity using the gas supply device. The nitrogen passes through the dryer and the steam generator in sequence. When the nitrogen enters the containment cavity, the humidity inside the containment cavity is 80%.

[0026] In one embodiment, when the concentration of aerosol particles in the containment cavity reaches a preset value, the aerosol generator and the air supply component are turned off, and the electric field generator is turned on, so that the electric field force on the aerosol particles is balanced with the gravity.

[0027] In one embodiment, the electric field force and gravity acting on the aerosol particles are balanced, including:

[0028] The aerosol particles have an initial velocity under their own gravity when they enter the containment cavity. The initial intensity of the electric field in the containment cavity is first set to E1, and the intensity of the electric field is adjusted to E within a preset time, so that E1 is greater than E, so as to achieve a balance between the electric force and gravity on the aerosol particles.

[0029] The electric field generator in the aforementioned aerosol deposition experimental apparatus creates an electric field within the containment cavity, subjecting migrating aerosol particles to an electric force. This electric force balances the gravity of the aerosol particles, eliminating the influence of gravity on their migration. Furthermore, it facilitates thermophoresis or diffusion-coating experiments to perform single-mechanism experiments, aiding in the development of single-deposition mechanism models and enabling more accurate measurement of aerosol deposition amounts. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of an aerosol deposition experimental apparatus provided in some embodiments of this application.

[0031] Explanation of reference numerals in the attached figures:

[0032] 10. Aerosol generator; 20. Experimental container; 21. Receiving cavity; 211. First cavity wall; 212. Second cavity wall; 30. Auxiliary mechanism; 31. Heating element; 32. Condenser; 33. Air supply element; 34. Air supply element; 35. Dryer; 36. Air heater; 37. Steam generator; 38. Aerosol measuring instrument; 39. Condensate measuring instrument; 40. Sampling element; 50. Measuring instrument; X, First direction; 100. Aerosol deposition experimental equipment. Detailed Implementation

[0033] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0034] In the description of this application, 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", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application 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, and therefore should not be construed as a limitation of this application.

[0035] 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 application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0036] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," 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 expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0037] In this application, unless otherwise expressly 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," "on top of," and "over" 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.

[0038] 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.

[0039] Please see Figure 1This application provides an aerosol deposition experimental apparatus 100 for simulating nuclear reactor accidents in some embodiments. The aerosol deposition experimental apparatus 100 includes an aerosol generator 10, an experimental container 20, an electric field generator, and an auxiliary mechanism 30. The aerosol generator 10 is used to generate aerosol particles; the experimental container 20 has a receiving cavity 21 inside, which is connected to the aerosol generator 10 and allows aerosol particles to enter; the electric field generator is installed on the experimental container 20 and can form an electric field in the receiving cavity 21; the auxiliary mechanism 30 is used in conjunction with the electric field generator to jointly conduct thermophoresis or diffusion-phoresis experiments on the aerosol particles in the receiving cavity 21, wherein the electric field force and gravity acting on the aerosol particles are balanced.

[0040] The aerosol generator 10 is an instrument that converts solid or liquid substances into suspended particles through physical means. In the embodiments of this application, the particle size range of the particles generated by the aerosol generator 10 is 1 μm to 5 μm. When the particle size is greater than 1 μm, the lateral motion of the aerosol due to Brownian diffusion is negligible, allowing for the study of other behaviors of the aerosol particles.

[0041] The containment cavity 21 within the experimental container 20 provides a space for aerosol particles to move, and works in conjunction with the electric field generator and auxiliary mechanisms 30 to simulate the environment during a nuclear power plant accident, in order to study the behavior of aerosol particles. For example, the experimental container 20 is a base with an internal containment cavity 21. The experimental container 20 and the aerosol generator 10 are connected by pipes to transport aerosol particles into the containment cavity 21. The connection between the pipes and the experimental container 20 can be, but is not limited to, snap-fit ​​or threaded connections, to facilitate the replacement of damaged parts with new ones if the pipes or the experimental container 20 are damaged. This reduces maintenance costs compared to replacing the pipes and the experimental container 20 together.

[0042] The working principle of the aerosol deposition experimental device 100 is explained below.

[0043] Aerosol generator 10 generates aerosol particles, which enter the containment cavity 21 of experimental container 20 and migrate within it. Subsequently, an electric field generator and auxiliary mechanism 30 are activated. The electric field generator creates an electric field within the containment cavity 21, subjecting the migrating aerosol particles to an electric force. This electric force balances the aerosol particles' own gravity, thus eliminating the influence of gravity on the aerosol particles during their migration.

[0044] This allows for thermophoresis or diffusion-coating experiments on aerosol particles to perform single-mechanism experiments, and also helps in developing single-deposition mechanism models and more accurately measuring the amount of aerosol deposition.

[0045] like Figure 1 As shown, in some embodiments, the receiving cavity 21 extends along the first direction X, and the receiving cavity 21 has a first cavity wall 211 and a second cavity wall 212 spaced apart along the first direction X. The first cavity wall 211 is in communication with the aerosol generator 10. The auxiliary mechanism 30 includes a heating element 31, which extends along the first direction X. The temperature of the heating element 31 gradually decreases from the first cavity wall 211 toward the second cavity wall 212.

[0046] The heating element 31 can be constructed as a plurality of heating wires, all of which are spaced apart along the first direction X. The heating temperature of all the heating wires gradually decreases from the first cavity wall 211 toward the second cavity wall 212 to form a temperature gradient within the receiving cavity 21. The sampling element 40 can be made of a material with good thermal conductivity and high surface cleanliness.

[0047] When aerosol particles enter the containment cavity 21 and the heating element 31 is operating, because the temperature on the side where the first cavity wall 211 is located is higher than the temperature on the side where the second cavity wall 212 is located, this asymmetric momentum transfer will give the aerosol particles a net force, namely thermophoretic force, and drive the aerosol particles to move along the temperature gradient from the high-temperature region to the low-temperature region. When the aerosol particles move to the second cavity wall 212, they are captured by the sampling element 40 and thus deposited on the surface of the sampling element 40.

[0048] Thus, by creating a temperature gradient, the movement trajectory of aerosol particles can be controlled using thermophoretic force, thereby achieving aerosol particle deposition and completing the thermophoresis experiment. Secondly, the experimental results can be compared with theoretical thermophoresis models (such as thermophoretic force formulas) to verify or correct the accuracy of the models.

[0049] Finally, the heating element 31 can be segmented along the first direction X to form, for example, a high-temperature segment, a medium-temperature segment, and a low-temperature segment. This allows for the formation of a large-scale, temperature-uniform region within the accommodating cavity 21, enabling a large-scale thermophoresis-driven region and ensuring a relatively stable temperature field, thus providing conditions for long-term observation.

[0050] Specifically, in some embodiments, the temperature gradient of the heating element 31 is a, where 1000K / m < a < 4000K / m.

[0051] It should be noted that in order to control the temperature gradient, high-power heating is required at both ends of the heating element 31. The temperature difference, the distance length, and the temperature gradient a are interrelated.

[0052] Taking heating element 31 as an example, its left end is heated to 600K and its right end is heated to 400K, with a distance of 0.05m between them. At this time, the temperature gradient is 4000K / m. For another example, its left end is heated to 600K and its right end is heated to 550K, with a distance of 0.05m between them. At this time, the temperature gradient is 1000K / m.

[0053] By limiting the range of the temperature gradient, we can not only reduce the probability of aerosol particle control failure or low efficiency due to insufficient thermophoretic force to overcome airflow disturbances, but also reduce the risk of strong natural convection caused by excessively large gradients, which could disrupt the stable temperature field and even lead to uncontrollable aerosol particle movement. Moreover, excessive thermophoretic force may also cause particles to collide with the surface at high speed, resulting in rebound or secondary suspension.

[0054] Therefore, setting a better temperature gradient range can achieve the best balance between the efficiency and energy consumption of thermophoretic deposition / separation.

[0055] In some embodiments, the second cavity wall 212 is provided with a sampling element 40 for capturing deposited aerosol particles. The auxiliary mechanism 30 also includes a condenser 32, which is installed on and covers the second cavity wall 212. The sampling element 40 is installed on the side of the condenser 32 away from the second cavity wall 212, and the sampling element 40 is detachably connected to the condenser 32.

[0056] The condenser 32 can be constructed as a plate, covering the entire second chamber wall 212. The condenser 32 can be fixed to the second chamber wall 212, or installed on the second chamber wall 212 in a easily detachable manner, facilitating timely replacement in case of damage and reducing maintenance costs. The connection between the condenser 32 and the sampling element 40 can be, but is not limited to, snap-fit ​​or threaded connections, allowing the user to remove the sampling element 40 from the condenser 32 after a single experiment and measure the aerosol particles deposited on it. By measuring the distribution, quantity, or morphology of the deposited particles on the sampling element 40, the user can quantify key parameters such as thermophoresis efficiency and migration rate.

[0057] During the migration of aerosol particles from the first cavity wall 211 to the second cavity wall 212, when the aerosol particles approach the condenser 32, the condenser 32, along with components such as the experimental container 20, can simulate the water vapor condensation process caused by temperature within the spatial containment cavity 21 to conduct diffusion-electrophoresis experiments. Furthermore, by adjusting the temperature of the condenser 32, the amount of water vapor condensed on the surface of the sampling piece 40 can be precisely controlled, thereby quantitatively studying the impact of condensation on diffusion-electrophoresis deposition efficiency.

[0058] In some embodiments, the auxiliary mechanism 30 further includes a plurality of air supply components 33, all of which are distributed at intervals along the first direction X within the receiving cavity 21, and the air supply components 33 are used to supply air into the receiving cavity 21.

[0059] For example, a fan can be used as the air supply component 33 to reduce the difficulty of obtaining the air supply component 33. Figure 1 In the example shown, there are five air supply components 33, all of which are spaced apart along the first direction X on the same side of the receiving cavity 21. During thermophoresis or diffusion-coagulation experiments, the air supply components 33 generate controllable and uniform forced convection, thereby suppressing or replacing unstable natural convection, ensuring the stability of the experimental environment, and simulating application scenarios to study the thermophoresis or diffusion-coagulation behavior of aerosol particles in flow. Furthermore, the air supply components 33 also help maintain the temperature gradient and aerosol particle concentration within the receiving cavity 21, and blow away impurities within the receiving cavity 21 to purify the environment.

[0060] Please continue reading. Figure 1 In some embodiments, the auxiliary mechanism 30 further includes an air supply component 34, a dryer 35, an air heater 36, and a steam generator 37. The dryer 35 is connected between the air supply component 34 and the air heater 36. The air heater 36 is connected to the receiving cavity 21. The steam generator 37 is connected between the dryer 35 and the air heater 36.

[0061] The air heater 36 and the steam generator 37 can be selectively connected to the receiving cavity 21. When the air heater 36 is connected to the receiving cavity 21, a thermophoresis experiment is performed; when the steam generator 37 is selectively connected to the receiving cavity 21, a diffusion electrophoresis experiment is performed.

[0062] In other words, during the thermophoresis experiment, the heating element 31 is activated first. Once the temperature gradient within the containment cavity 21 reaches a preset value, the gas supply element 34, dryer 35, and air heater 36 are turned on. The nitrogen gas supplied by the gas supply element 34 passes through the dryer 35 and air heater 36 sequentially before entering the containment cavity 21, at which point the humidity within the containment cavity 21 is 0%. Subsequently, the air supply element 33, aerosol generator 10, and electric field generator are activated. The aerosol particles generated by the aerosol generator 10 enter the containment cavity 21 and mix with the nitrogen gas, thereby performing thermophoretic deposition.

[0063] During the diffusion electrophoresis experiment, the gas supply unit 34, dryer 35, and steam generator 37 are activated. The nitrogen gas supplied by the gas supply unit 34 passes sequentially through the dryer 35 and steam generator 37, at which point the humidity inside the containment cavity 21 is 80%. Subsequently, the air supply unit 33, aerosol generator 10, and electric field generator are activated. The aerosol particles generated by the aerosol generator 10 enter the containment cavity 21 and mix with the nitrogen gas, thereby performing diffusion electrophoresis deposition.

[0064] The above setup simplifies the switching between thermophoresis and diffusion chromatography in the aerosol deposition experimental device 100, making it easier for the aerosol deposition experimental device 100 to perform different experiments.

[0065] In some embodiments, the receiving cavity 21 is constructed as a cuboid, with a length of 100 cm, a width of 60 cm, and a depth of 60 cm along the first direction X. Therefore, the volume of the receiving cavity 21 is 0.36 m³. 3 .

[0066] In actual experiments, the amount of aerosol particles injected into the containment cavity 21 at a time is 100g, which saves experimental costs. Moreover, because the volume of the containment cavity 21 is small, it is beneficial to control the uniformity of temperature, humidity and aerosol concentration. Similarly, the size of the corresponding experimental container 20 can also be reduced, thereby reducing the space occupied by the experimental container 20.

[0067] Furthermore, some embodiments of this application also provide an aerosol deposition experimental method for simulating nuclear reactor accidents, which employs the aerosol deposition experimental equipment 100 described in the above embodiments. The aerosol deposition experimental method includes:

[0068] Nitrogen gas is injected into the receiving cavity 21 of the experimental container 20;

[0069] The air supply component 33 of the auxiliary mechanism 30 is activated, and aerosol particles are injected into the receiving cavity 21 using the aerosol generator 10.

[0070] When the concentration of aerosol particles in the containment cavity 21 reaches the preset value, the aerosol generator 10 and the air supply component 33 are turned off, and the electric field generator is turned on. The electric field force and gravity on the aerosol particles are balanced. The auxiliary mechanism 30 works with the electric field generator to conduct thermophoresis or diffusion experiments on the aerosol particles.

[0071] The specific process is as follows: Nitrogen gas meeting the requirements is injected into the containment cavity 21 using components such as the gas supply unit 34 (e.g., an air compressor tank) and the dryer 35. For example, dry nitrogen gas is injected during thermophoresis experiments, while moist nitrogen gas is injected during diffusion electrophoresis experiments. Subsequently, the air supply unit 33 is turned on to create a near-realistic experimental environment within the containment cavity 21. Next, the aerosol generator 10 is activated, injecting aerosol particles (such as particles containing SiO2) generated by the aerosol generator 10 into the containment cavity 21 of the experimental container 20. These particles then migrate within the containment cavity 21.

[0072] Once the aerosol particle concentration in the containment cavity 21 reaches a preset value, the aerosol generator 10 and the air supply component 33 are turned off, and the electric field generator and auxiliary mechanism 30 are turned on. The electric field generator creates an electric field within the containment cavity 21, subjecting the aerosol particles migrating within it to an electric force. This electric force balances the gravity of the aerosol particles, eliminating the influence of gravity on the particles during migration. The auxiliary mechanism 30 works in conjunction with the electric field generator to facilitate thermophoresis or diffusion-phoresis experiments on the aerosol particles.

[0073] This not only enables single-mechanism experiments but also helps in developing single-deposition mechanism models and allows for more accurate measurement of aerosol deposition amounts.

[0074] In some embodiments, the auxiliary mechanism 30 further includes a heating element 31 and a gas supply element 34. The auxiliary mechanism 30, in conjunction with an electric field generator, performs thermophoresis experiments on aerosol particles, including:

[0075] Before injecting nitrogen into the cavity 21 of the experimental container 20, the cavity 21 is heated by the heating element 31 to create a temperature gradient inside the cavity 21.

[0076] When nitrogen is injected into the containment cavity 21 of the experimental container 20, nitrogen is injected into the containment cavity 21 using the gas supply device 34. The nitrogen passes through the dryer 35 and the air heater 36 in sequence. When the nitrogen enters the containment cavity 21, the humidity inside the containment cavity 21 is 0%.

[0077] For example, before conducting the thermophoresis experiment, the heating element 31 is turned on to ensure that the temperature gradient within the containment cavity 21 is between 1000 K / m < a < 4000 K / m. Then, the thermophoresis experiment is formally started, and nitrogen gas that has been processed by the dryer 35 and the air heater 36 is injected into the containment cavity 21 to obtain dry nitrogen gas, so that the humidity within the containment cavity 21 is 0%.

[0078] This allows for a stable temperature environment during the experiment, creating an optimal experimental setting and achieving a balance between the efficiency and energy consumption of thermophoretic deposition / separation. Furthermore, introducing dry nitrogen not only eliminates the interference of moisture on the thermophoretic force and reduces the impact of droplet evaporation on aerosol particle size, but also ensures the stability of particle chemical properties, reduces unknown variables, and improves experimental reproducibility.

[0079] In some embodiments, the auxiliary mechanism 30 further includes an air supply component 34, a dryer 35, and a steam generator 37. The auxiliary mechanism 30, in conjunction with an electric field generator, performs diffusion-coating experiments on aerosol particles, including:

[0080] When nitrogen is injected into the containment cavity 21 of the experimental container 20, nitrogen is injected into the containment cavity 21 using the gas supply device 34. The nitrogen passes through the dryer 35 and the steam generator 37 in sequence. When the nitrogen enters the containment cavity 21, the humidity inside the containment cavity 21 is 80%.

[0081] During the diffusion electrophoresis experiment, the nitrogen supplied by the gas supply unit 34 passes sequentially through the dryer 35 and the steam generator 37, ensuring that all particles in the nitrogen gas are dried first. This eliminates the differences caused by varying initial moisture content among different particles, ensuring that all particles have the same initial moisture content. Subsequently, these particles are humidified together. This process artificially amplifies the differences in particle size during diffusion electrophoresis, efficiently separating highly hygroscopic submicron-sized particles from nano-sized particles or non-hygroscopic particles.

[0082] In some embodiments, when the concentration of aerosol particles in the accommodating cavity 21 reaches a preset value, the aerosol generator 10 and the air supply component 33 are turned off, and the electric field generator is turned on, so that the electric field force and gravity on the aerosol particles are balanced.

[0083] For example, hydrophobic aerosol particles containing SiO2 were used in the experiment. During the experiment, when the concentration of the injected aerosol particles reached 10... 4 pcs / cm 3 When this happens, the aerosol generator 10 and the air supply unit 33 are turned off to stop the injection of aerosol particles. This prevents aerosols from condensing in the containment cavity 21, which could affect subsequent experimental results. Then, the electric field generator is turned on, and the electric field strength is ensured to meet the following requirements so that the electric force received by the aerosol particles meets the requirements.

[0084] That is, the electric field force on the aerosol particles is , , ρ p The density of the aerosol. Let q be the diameter of the aerosol, q be the charge, and E be the electric field strength.

[0085] In this way, the electric field force on the aerosol particles not only does not affect their migration but also balances with their own gravity, thus eliminating the influence of gravity on the behavior of the aerosol particles. The electric field force can be adjusted by regulating the electric field strength generated by the electric field generator to suit aerosol particles of different sizes, and related experiments can be conducted.

[0086] In some embodiments, the balance between the electric field force and gravity acting on aerosol particles includes:

[0087] When aerosol particles enter the containment cavity 21, they have an initial velocity under their own gravity. The initial intensity of the electric field in the containment cavity 21 is first set to E1, and the intensity of the electric field is adjusted to E within a preset time, so that E1 is greater than E, so as to achieve a balance between the electric force and gravity on the aerosol particles.

[0088] For example, during the thermophoresis experiment, the heating element 31 is first activated to heat the receiving cavity 21, ensuring that the temperature gradient within the receiving cavity 21 is within a preset range. Then, nitrogen gas and aerosol particles meeting the requirements are injected into the receiving cavity 21 using the gas supply element 34 and the aerosol generator 10, wherein the particle size can be 1 μm. When the aerosol concentration within the receiving cavity 21 reaches 10... 4 pcs / cm 3 When the aerosol generator 10 and the air supply unit 33 are turned off, the electric field generator is turned on.

[0089] Because the aerosol particles have an initial velocity due to their own gravity during injection into the receiving cavity 21, the electric field generator is adjusted to eliminate the influence of this initial velocity. The electric field strength is set to E1, and then adjusted to E within time τ. The relationship between E1, E, and τ is as follows: .

[0090] This configuration is intended to eliminate the influence of the initial velocity of aerosol particles when they enter the containment cavity 21 and to balance gravity.

[0091] Subsequently, timing begins, and the initial aerosol concentration within the containment cavity 21 is detected using an aerosol measuring instrument 38. As the aerosols are deposited through thermophoresis, the aerosol concentration within the containment cavity 21 gradually decreases, and this concentration change can be monitored continuously using the aerosol measuring instrument 38. Furthermore, temperature, pressure, and vapor concentration can be measured using a measuring device 50 to continuously monitor the gas state within the containment cavity 21. The process continues until the aerosol concentration drops to 10... 3 pcs / cm 3 Record the time taken, remove the sample 40, and pause the experiment. Clean the experimental chamber, put the sample 40 without deposited particles back into the receiving chamber 21, increase the particle size of the aerosol particles and repeat the above steps until the particle size of the aerosol particles reaches 5 μm, thus completing a single thermophoresis experiment.

[0092] The procedure for diffusion electrophoresis differs from that for thermophoresis. The specific steps of diffusion electrophoresis are as follows:

[0093] Nitrogen gas and aerosol particles meeting the requirements are injected into the containment chamber 21 using the gas supply unit 34, steam generator 37, and aerosol generator. When the aerosol concentration in the containment chamber 21 reaches 10... 4 pcs / cm 3At this time, the aerosol generator 10 and the air supply unit 33 are turned off, and the electric field generator is turned on. Similarly, the electric field generator is used to eliminate the influence of the initial velocity of the aerosol particles when they enter the containment cavity 21 and to balance gravity.

[0094] Subsequently, the condenser 32 and the condensate measuring instrument 39 were turned on, and the flow rate of the condensate was controlled at 1 g / m³. 3 s~100g / m 3 Within seconds. Immediately afterwards, timing begins, and the initial aerosol concentration within the containment cavity 21 is detected using an aerosol measuring instrument 38. As the aerosol diffuses and deposits, the aerosol concentration within the containment cavity 21 gradually decreases, and this concentration change can be monitored continuously using the aerosol measuring instrument 38. Furthermore, temperature, pressure, and vapor concentration can be measured using a measuring device 50 to continuously monitor the gas state within the containment cavity 21. The process continues until the aerosol concentration drops to 10... 3 pcs / cm 3 Record the time taken, remove the sample 40, and pause the experiment. Clean the experimental chamber, put the sample 40 without deposited particles back into the receiving chamber 21, increase the particle size of the aerosol particles and repeat the above steps until the particle size of the aerosol particles reaches 5 μm, thus completing a single diffusion phoresis experiment.

[0095] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0096] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An aerosol deposition experimental apparatus for simulating nuclear reactor accidents, characterized in that, include: Aerosol generator, used to generate aerosol particles; The experimental container has an internal cavity that is connected to the aerosol generator and allows the aerosol particles to enter. An electric field generator is installed on the experimental container and is capable of generating an electric field within the containment cavity; An auxiliary mechanism, used in conjunction with the electric field generator, is used to conduct thermophoresis or diffusion-electrophoresis experiments on aerosol particles within the containment cavity, wherein the electric field force and gravity acting on the aerosol particles are balanced.

2. The aerosol deposition experimental apparatus according to claim 1, characterized in that, The receiving cavity extends along a first direction, and the receiving cavity has a first cavity wall and a second cavity wall spaced apart along the first direction, the first cavity wall being in communication with the aerosol generator; The auxiliary mechanism includes a heating element that extends along the first direction from the first cavity wall toward the second cavity wall, and the temperature of the heating element gradually decreases.

3. The aerosol deposition experimental apparatus according to claim 2, characterized in that, The temperature gradient of the heating element is a, where 1000K / m < a < 4000K / m.

4. The aerosol deposition experimental apparatus according to claim 2, characterized in that, The second cavity wall is provided with a sampling element for capturing the deposited aerosol particles. The auxiliary mechanism also includes a condenser, which is installed on and covers the second cavity wall. The sampling element is installed on the side of the condenser away from the second cavity wall, and the sampling element is detachably connected to the condenser.

5. The aerosol deposition experimental apparatus according to claim 2, characterized in that, The auxiliary mechanism also includes a plurality of air supply components, all of which are spaced apart in the receiving cavity along the first direction, and the air supply components are used to supply air into the receiving cavity.

6. The aerosol deposition experimental apparatus according to any one of claims 1 to 5, characterized in that, The auxiliary mechanism also includes an air supply component, a dryer, an air heater, and a steam generator. The dryer is connected between the air supply component and the air heater. The air heater is connected to the receiving cavity. The steam generator is connected between the dryer and the air heater. The air heater and the steam generator are selectively connected to the receiving cavity. When the air heater is connected to the receiving cavity, the thermophoresis experiment is performed; when the steam generator is selectively connected to the receiving cavity, the diffusion electrophoresis experiment is performed.

7. An aerosol deposition experimental method for simulating nuclear reactor accidents, characterized in that, The aerosol deposition experimental apparatus as described in any one of claims 1 to 6, wherein the aerosol deposition experimental method comprises: Nitrogen gas is injected into the containing cavity of the experimental container; Activate the air supply component of the auxiliary mechanism and inject aerosol particles into the containment cavity using an aerosol generator; When the concentration of aerosol particles in the containment cavity reaches a preset value, the aerosol generator and the air supply component are turned off, and the electric field generator is turned on, so that the electric field force and gravity on the aerosol particles are balanced; the auxiliary mechanism works with the electric field generator to conduct thermophoresis or diffusion experiments on the aerosol particles.

8. The aerosol deposition experimental method according to claim 7, characterized in that, The auxiliary mechanism further includes a heating element and a gas supply element. The auxiliary mechanism, in conjunction with the electric field generator, performs a thermophoresis experiment on the aerosol particles, including: Before injecting nitrogen into the cavity of the experimental container, the cavity is heated by the heating element to create a temperature gradient inside the cavity. When nitrogen is injected into the containment cavity of the experimental container, the nitrogen is injected into the containment cavity using the gas supply device. The nitrogen passes through a dryer and an air heater in sequence. When the nitrogen enters the containment cavity, the humidity inside the containment cavity is 0%.

9. The aerosol deposition experimental method according to claim 7, characterized in that, The auxiliary mechanism also includes a gas supply unit, a dryer, and a steam generator. The auxiliary mechanism, in conjunction with the electric field generator, performs diffusion-phoresis experiments on the aerosol particles, including: When nitrogen is injected into the containment cavity of the experimental container, the nitrogen is injected into the containment cavity using the gas supply device. The nitrogen passes through the dryer and the steam generator in sequence. When the nitrogen enters the containment cavity, the humidity inside the containment cavity is 80%.

10. The aerosol deposition experimental method according to claim 7, characterized in that, When the concentration of aerosol particles in the containment cavity reaches a preset value, the aerosol generator and the air supply component are turned off, and the electric field generator is turned on, so that the electric field force and gravity on the aerosol particles are balanced.

11. The aerosol deposition experimental method according to claim 10, characterized in that, The balance between the electric field and gravity acting on the aerosol particles includes: The aerosol particles have an initial velocity under their own gravity when they enter the containment cavity. The initial intensity of the electric field in the containment cavity is first set to E1, and the intensity of the electric field is adjusted to E within a preset time, so that E1 is greater than E, so as to achieve a balance between the electric force and gravity on the aerosol particles.

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