Particle collision dynamics experiment system and method in vacuum microgravity environment
By designing a particle collision experiment system under vacuum microgravity environment, the problem of mesoscopic particle cluster collision dynamics experiments in vacuum microgravity environment is solved, and repeatable and multivariate experiments are realized, cost is reduced, and actual space conditions are simulated.
Patent Information
- Application Number
- CN202510305804.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-14
- Publication Date
- 2025-06-27
AI Technical Summary
The prior art is difficult to perform repeatable, multivariable mesoscopic scale particle cluster collision dynamics experiments in vacuum microgravity environments, especially with limitations in cost and experiment duration.
A particulate matter collision experiment system in vacuum microgravity environment was designed, including vacuum drop tower, control system, electrical system and shooting system. Different experimental caps and release mechanisms were used to achieve experiments on different types of particulate matter, including collision experiments of frozen particulate matter and anhydrous particulate matter.
Repeatable and multivariable particle collision dynamics experiments under vacuum microgravity environments, reducing experimental costs, improving the economic and scientific value of the experiment, and being able to simulate actual conditions in space.
Smart Images
Figure CN120220511A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a method for designing an experimental system for physically simulating the collision growth and motion of mesoscale particle clusters under vacuum microgravity conditions on the ground, which helps to establish and improve the kinetic theory of particulate matter collision growth in the space environment and can be applied to scenarios such as planet formation, exploration of extraterrestrial celestial body surfaces, construction of Earth-Moon space infrastructure, and development and utilization of space resources. Background Art
[0002] The mechanism of material accumulation and growth between the micron and centimeter scales, especially the dynamic processes of multiphase complex systems at the sub-micron to sub-millimeter mesoscale, is a cross-cutting frontier field in mechanics, astronomy, and earth science today, and is also the application foundation frontier that drives the development of technologies for exploring extraterrestrial celestial body surfaces, constructing Earth-Moon space infrastructure, and developing and utilizing space resources.
[0003] Currently, mesoscale particulate matter dynamics experiments are carried out on both space platforms and ground platforms. Taking advantage of the characteristics of the stable microgravity environment on the space station or satellite, international research teams have studied the mechanisms and properties of basic physical processes such as the aggregation of particulate matter to form clumps. However, due to constraints such as the limited opportunities for carrying experiments and the high experimental costs on space platforms, it is impossible to conduct repeatable and multi-variable experiments at low cost for a long time. Summary of the Invention
[0004] The technical problem solved by the present invention is to provide a physical simulation experimental system and method for the collision dynamics and structure formation of mesoscale particle clusters under vacuum microgravity conditions on the ground.
[0005] The technical solution adopted by the present invention is: a particulate matter collision dynamics experimental system under vacuum microgravity conditions, comprising a vacuum drop tower, a drop tower top cover, a control system, an electrical system, and a photographing system. The vacuum drop tower includes a tower body and a drop tower top cover. The drop tower top cover is installed together with the tower body according to different experiments to form a sealed structure, creating the required vacuum and microgravity environment for the experiment. The top cover includes a frozen particulate matter experimental top cover and a non-aqueous particulate matter experimental top cover.
[0006] A refrigeration system is installed above the frozen particulate matter experimental top cover, and a sample chamber and a release mechanism are installed below. The control system controls the refrigeration system to make the environment in the sample chamber meet the experimental requirements and complete the preparation of frozen samples at different positions.
[0007] A release mechanism and non-aqueous particle samples are placed at different positions are installed below the non-aqueous particulate matter experimental top cover.
[0008] The release mechanism releases samples at different positions at different times in a free-fall manner under the control of the control system, and the photographing system outside the tower photographs the released samples and their collision processes.
[0009] Preferably, the refrigeration system is that a refrigeration compressor is installed on the top cover of the drop tower through a vacuum flange, a cold head and a transition piece are installed at the lower end of the vacuum flange, and the sample chamber is connected through the transition piece.
[0010] Preferably, the frozen sample is prepared in the following manner:
[0011] Sample slots are installed at different heights in the sample chamber through a mechanical structure, and the centers of the sample slots at different heights are located on the same axis of the sample chamber;
[0012] Turn on the refrigeration compressor to lower the temperature in the sample chamber to below 130K and maintain stability;
[0013] Inject micron-sized atomized droplets into the sample chamber. The droplets condense into ice particles in the sample chamber and form random ballistic deposition aggregates in the sample slots until the sample size grows to 1.5 - 2 cm.
[0014] Preferably, the number of sample slots is two, and the distance between them ranges from 10 to 20 cm.
[0015] Preferably, the anhydrous particulate collision test includes two types of experiments: low-speed experiments and high-speed experiments;
[0016] For the low-speed collision experiment of anhydrous particulates, sample slots are installed at different heights below the top cover through a mechanical structure, and the centers of the sample slots at different heights are located on the same axis of the vacuum drop tower; the number of sample slots is two, and the distance between them ranges from 10 to 50 cm; for the high-speed collision experiment of anhydrous particulates, an ejection mechanism is set below, the sample configuration above remains unchanged, and the spacing ranges from 1.5 to 2.0 m.
[0017] Preferably, in the low-speed experiment and the frozen particulate experiment, the sample slots are installed on the release device in a cantilever manner; the release device includes a fixed rod and a rotary solenoid valve; the fixed rod includes a vertical rod and a horizontal rod. The vertical rod is used to connect to the top cover of the drop tower, the horizontal rod is fixedly installed on the vertical rod, and the sample slot is connected to the horizontal rod through a rotary solenoid valve in a cantilever manner; when an experiment is required, the rotary solenoid valve is powered off, the sample slot and the cantilever rotate, and the frozen sample on the sample slot falls freely.
[0018] Preferably, in the high-speed experiment, the upper sample slot is installed on the release device in a cantilever manner; the lower sample slot is placed on the ejection mechanism in the vacuum drop tower, and the release device makes the anhydrous particulates above fall freely, and the ejection mechanism accelerates the anhydrous particulates below upward.
[0019] Preferably, the relative speed of the low-speed collision experiment is 0.01 - 3 m / s, and the relative speed of the high-speed collision experiment can reach 5 - 8 m / s.
[0020] An experimental method for particulate collision dynamics in a vacuum microgravity environment, comprising:
[0021] According to the current pre-experiment content, select the corresponding drop tower top cover. When conducting an anhydrous particulate collision experiment, perform the following steps:
[0022] Select an anhydrous particle sample simulating the composition of celestial bodies and load it on the release device; if a low-speed collision experiment is to be carried out, adjust the distance between the two release devices to the required position; if a high-speed collision experiment is to be carried out, set up an ejection mechanism below and load the sample through the release device above;
[0023] Close the drop tower top cover and evacuate the inside of the drop tower;
[0024] The control system controls the release device to release the sample, and the samples collide with a certain relative speed during the free fall process; the camera system moves outside the drop tower together with the sample and takes pictures of the sample collision situation through the observation window;
[0025] When conducting a frozen particulate collision experiment, perform the following steps:
[0026] Prepare a frozen particle aggregate sample: adjust the distance between the release devices; turn on the refrigerator to cool the temperature inside the sample chamber below 130K and maintain stability; introduce micron-sized atomized droplets into the sample chamber, and the droplets condense into ice particles in the sample chamber to form a random ballistic deposition aggregate in the sample groove of the release device until the sample size grows to 1.5 - 2 cm;
[0027] Seal the drop tower top cover with the vacuum drop tower and evacuate the inside of the drop tower;
[0028] The control system controls the release device to release the sample, and the samples collide with a certain relative rate during the free fall process; the high-speed camera moves outside the drop tower together with the sample and takes pictures of the sample collision situation through the observation window.
[0029] The beneficial effects of the present invention compared with the prior art are:
[0030] The present invention provides a repeatable, multi-variable and relatively economical experimental method for particulate dynamics in a vacuum microgravity environment. The aggregate is in a free fall state during the collision process, in a weightless state, which matches the actual conditions in space.
[0031] The present invention uses a refrigerator to cool the sample chamber to prepare a frozen particulate aggregate sample, which is safer and more reliable than using liquid nitrogen to cool the sample chamber. The high-speed camera is installed on the photography track to run, and the camera is precisely controlled through a stepping motor and a shutter controller, and can take more stable and clear pictures of the collision scene. Description of the Drawings
[0032] Figure 1 Tower structure design drawing;
[0033] Figure 2 Freezing sample experiment top cover structure design drawing;
[0034] Figure 3 Sample chamber schematic diagram;
[0035] Figure 4 Schematic diagram of the principle of the sample release device
[0036] Figure 5 Schematic diagram of the mechanical structure connection relationship and working principle of the freezing particulate aggregate collision experiment device;
[0037] Figure 6 Flow chart of the freezing particulate aggregate collision experiment. Specific implementation manners
[0038] The present invention will be further described below in conjunction with embodiments.
[0039] The present invention provides a particulate collision experiment system under a vacuum microgravity environment, including a small vacuum drop tower, a sample release mechanism, a sample ejection mechanism, a refrigerator, a sample chamber, a control system, an electrical system, and a photographing system, which can conduct collision experiments on various particulate aggregates, including anhydrous particulate aggregates and frozen particulate aggregates. The small vacuum drop tower has the ability to construct a microgravity vacuum environment, flexibly carry different experimental devices and samples to carry out microgravity experiments, and can realize the rapid and convenient conversion of different experimental contents and experimental devices.
[0040] Vacuum drop tower: It is a metal closed structure used to construct a vacuum and microgravity environment. The tower body is a three-section structure, namely the top cover, the observation section and the bottom. The top cover of the drop tower is a detachable structure, and the top cover with different functional properties can be replaced according to different experimental requirements. The release mechanism, refrigerator, etc. are installed on the top cover according to needs; there are two glass observation windows in the observation section, which can be used to observe the internal experimental situation of the drop tower, set up a camera to shoot the experimental process and supplement light for the internal environment of the tower; the bottom includes a maintenance opening, which can be used for in-tower line maintenance, cleaning, and installation of ejection devices, etc. Figure 1 The drop tower structure design is shown. The present invention can meet the microgravity duration > 0.7 s through the tower body height design.
[0041] Anhydrous particulate experiment top cover: A release mechanism is installed below the top cover, which supports the collision experiment of anhydrous particulate aggregates (also known as anhydrous particle samples). Different sizes and shapes of anhydrous particulate cluster samples are released by controlling it through the control system.
[0042] Ice Particle Experiment Top Cover: The top cover is equipped with a refrigeration system, a sample chamber, and a release mechanism, supporting the implementation of micron-scale water ice particle aggregate collision experiments with a microgravity duration of not less than 0.5 s. Water ice particles condense in the sample chamber under the top cover, and the sample is released by controlling the flap movement in the sample chamber through a control system. Figure 2 Shows the design of the ice particle experiment top cover, Figure 3 which is a simplified schematic diagram of the sample chamber and the release mechanism.
[0043] Refrigeration System: Installed above the ice particle experiment top cover, used for refrigerating the sample chamber inside the top cover.
[0044] Release Mechanism: Installed under the drop tower top cover, used to carry and release particulate cluster samples of different shapes and sizes.
[0045] Ejection Mechanism: In the anhydrous particulate high-speed collision experiment, the ejection mechanism is installed at the bottom of the drop tower, used to accelerate the sample below.
[0046] Control System: Completes the synchronous control of the release mechanism, the ejection mechanism, and the imaging system.
[0047] Electrical System: Supplies power to the tower.
[0048] Imaging System: High-speed cameras, fixed on the guide rail, descending synchronously with the experimental payload to take pictures.
[0049] Guide Rail: Fixes the high-speed camera and controls its shooting of the cluster collision scene.
[0050] Anhydrous Particle Sample: The components are various analogs of celestial surface regolith, which are prepared by mixing rocks and minerals collected on Earth in a certain proportion to simulate the celestial bodies to be studied (such as primitive asteroids, asteroids, etc.). The main minerals include olivine, pyroxene, serpentine, Fe-Ni sulfide, etc. The shapes include spheres, cuboids, cylinders, and irregular shapes, with the size range from 1 cm to 20 cm and the maximum porosity up to 85%.
[0051] (I) Collision Experiment of Anhydrous Particle Aggregates
[0052] In the collision experiment of anhydrous particle aggregates, first, use a sample preparation mold to prepare particulate aggregate samples of different shapes, sizes, and porosities from mesoscale particles of different components. Load the samples onto a suitable release device, and achieve different relative collision rates by adjusting the release device spacing and controlling the release time. The experimental device is equipped with a parameter control system and a monitoring and display system, which can control the experimental parameters and is equipped with high-speed cameras, having the function of monitoring and displaying the experimental process.
[0053] The specific implementation steps of the anhydrous particle aggregate collision experiment are as follows:
[0054] Use a sample preparation mold to prepare aggregate samples of different shapes and sizes from mesoscale particulate matter of different components. The particulate matter can be monodisperse and polydisperse, with a particle size ranging from submicron to micron level, the particle shape can be spherical or irregular, and the component can be a single component or a mimic similar to the composition of celestial bodies.
[0055] Select a suitable release device according to the sample characteristics and load the sample. For low-speed collision experiments, adjust the distance between the two release devices to the required position, with the distance range of 10 - 50 cm and the relative speed of the low-speed collision experiment of 0.01 - 3 m / s. For high-speed collision experiments, set an ejection mechanism below, keep the upper sample configuration unchanged, with the distance range of 1.5 - 2.0 m and the relative speed of the high-speed collision experiment of 5 - 8 m / s.
[0056] Close the top cover of the drop tower and evacuate the inside of the drop tower to 1 Pa.
[0057] Control the release device to release the sample through the parameter control system, and the sample collides at a certain relative speed during the free fall process.
[0058] The high-speed camera moves outside the drop tower together with the sample and takes pictures of the sample collision situation through the observation window.
[0059] (2) Collision experiment of frozen particulate aggregates
[0060] In the collision experiment of frozen particulate aggregates, the refrigerator is connected to the sample chamber, and frozen particulate samples can be prepared in the sample chamber. The release device has the ability to carry and release particulate aggregates of different shapes, sizes, and porosities, and different relative collision rates are achieved by adjusting the distance between the release devices and controlling the release time. The experimental device is equipped with a parameter control system and a monitoring and display system, which can control the experimental parameters. It is equipped with a high-speed camera and has the function of monitoring and displaying the experimental process. Figure 5 Shows the mechanical structure connection relationship and working principle of the frozen particulate collision experimental device.
[0061] Figure 6 Shows the collision experiment process of frozen particulate aggregates. The specific implementation steps of the collision experiment of frozen particulate aggregates are as follows:
[0062] (1) Prepare frozen particle aggregate samples.
[0063] a) Suspend the top cover of the drop tower integrated with the refrigerator and the sample chamber directly above the drop tower, and adjust the distance between the release devices to the required position (range 10 - 20 cm).
[0064] b) Turn on the refrigerator to cool the temperature in the sample chamber below 130 K.
[0065] c) Micron-sized atomized droplets are introduced into the sample chamber, where they condense into ice particles and form random ballistic deposition (RBD) aggregates in the sample slot of the release device.
[0066] (2) When the micron-sized atomized droplets in c) are introduced using Figure 5 When the hose shown is filled, the top cover of the drop tower needs to be closed after the water ice particle aggregate is formed, and the inside of the drop tower needs to be evacuated to 1Pa. Figure 2 As shown, the atomizing gas inlet is integrated on the top cover, so the top cover and the tower body can be directly sealed before preparing the frozen particle aggregate sample, and this part only performs the vacuum operation.
[0067] (3) The release device is controlled by a parameter control system to release the sample, and the sample collides at a certain relative speed during the free fall process.
[0068] (4) A high-speed camera moves along with the sample on a track outside the drop tower and captures the collision of the sample through an observation window.
[0069] The temperature in the sample chamber is controlled below 130K mainly based on the following two considerations:
[0070] Simulate the temperature conditions for the stable existence of water ice in the solar system: The experimental environment should try to simulate the temperature conditions for the stable existence of water ice in the solar system. According to the definition of the "snow line" in the solar system (the snow line, in astronomy or planetary science, refers to the shortest distance in the protoplanetary disk that is far enough from the central protostar to make the temperature cold enough for volatile substances (such as hydrogen, helium, water, ammonia, methane, carbon dioxide and carbon monoxide, etc.) to condense into solid particles and accrete into microplanets.), the temperature at which micron-sized water ice particles can stably exist is about 150K or less. Studies have shown that controlling the experimental environment temperature below 130K can be closer to the actual temperature environment for the stable existence of water ice in the solar system.
[0071] Avoid sintering of water ice particles: The sintering of water ice particles will have a serious impact on the experimental output results. The formation time of the ice particle sintering neck is a function of temperature. Studies have shown that below 130K, the sintering neck will not begin to form until 28 hours later. The duration of an experiment is about one hour, which will not be affected by the sintering process. Therefore, in this type of experiment, in order to avoid the sintering of water ice particles, the sample temperature needs to be kept below 130K during the experiment. Taking the above into consideration, the temperature during the experiment needs to be controlled below 130K.
[0072] In the low-speed experiment of anhydrous particulate aggregates and the experiment of frozen particles of the present invention, the sample tank is installed on the release device in the form of a cantilever; the release device includes a fixed rod and a rotary solenoid valve; the fixed rod includes a vertical rod and a horizontal rod, the vertical rod is used to connect with the top cover of the drop tower, the horizontal rod is fixedly installed on the vertical rod, and the sample tank is connected to the lower part of the horizontal rod in the form of a cantilever through a rotary solenoid valve( Figure 4 as shown); when an experiment is needed, the rotary solenoid valve is powered off, the sample tank and the cantilever rotate, and the sample on the sample tank falls freely.
[0073] The captured images obtained by the present invention clearly present various results of particulate aggregates in collisions, covering phenomena such as adhesion, bouncing, and fragmentation. These results correspond to similar collision situations in the protoplanetary disk, and each result provides important scientific information for studying the formation of the protoplanetary disk. According to the experimental results, the collision speed thresholds and collision coefficients for particulate aggregates to adhere, bounce, and fragment can be obtained, and the effects of the porosity, uniformity, particle size, volume, shape, and composition of the sample on the collision results can also be obtained.
[0074] Example 1
[0075] The implementation steps of the collision experiment of frozen particulate aggregates are as Figure 6 shown:
[0076] (1) Prepare a sample of frozen particle aggregates.
[0077] d) Suspend the top cover of the drop tower integrated with a refrigerator and a sample chamber directly above the drop tower, and adjust the distance between the release devices to 11 cm. The cold head of the refrigerator is in close contact with the outer wall of the sample chamber. The material of the sample chamber is high-purity oxygen-free copper with a wall thickness of 4 mm.
[0078] e) Turn on the refrigerator to lower the temperature in the sample chamber below 130 K. To avoid the sintering phenomenon of ice particles, continuously monitor the temperature and maintain it below 130 K.
[0079] f) Introduce micron-sized atomized droplets (pure water) into the sample chamber. The droplets condense into ice particles in the sample chamber and form random ballistic deposition (RBD) aggregates in the sample tank of the release device until the sample size grows to 1.5 - 2 cm.
[0080] (2) Evacuate the inside of the drop tower to 1 Pa.
[0081] (3) Control the release device to release the sample through the parameter control system. The sample collides at a certain relative rate during the free fall process. Each release device contains a sample pool for the growth and aggregation of ice particles. Two release devices are installed in the drop tower in the upper and lower positions. After the control signal is triggered, the solenoid valve controls the cantilever to rotate downward, throws out the sample, and conducts free fall.
[0082] The two samples are released at t = 0 and t = t1 respectively, and the collision time is t = t c .
[0083] It can be known from the free-fall motion that
[0084] The relative velocity of the sample collision satisfies (to avoid hitting the lower sample cell);
[0085] The time required for the sample collision is
[0086] The falling distance at the time of collision is
[0087] For the distance h = 110 mn between the upper and lower release device sample cells, the maximum relative collision rate that can be achieved The minimum relative rate
[0088] (4) The high-speed camera moves with the sample outside the drop tower and takes pictures of the sample collision situation through the observation window.
[0089] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solution of the present invention without departing from the spirit and scope of the present invention. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.
Claims
1. A particle collision dynamic experimental system in a vacuum microgravity environment, comprising a vacuum drop tower, a drop tower top cover, a control system, an electrical system, and a shooting system. The vacuum drop tower comprises a tower body and a drop tower top cover, and is characterized in that: The drop tower top cover is selected according to different experiments and installed together with the tower body to form a closed structure, so as to construct the vacuum and microgravity environment required for the experiment; the top cover includes a frozen particle experiment top cover and an anhydrous particle experiment top cover; A refrigeration system is installed above the top cover of the frozen particle experiment, and a sample chamber and a release mechanism are installed below; the control system controls the refrigeration system so that the environment in the sample chamber meets the experimental requirements and completes the preparation of frozen samples at different positions; A release mechanism is installed under the top cover of the anhydrous particle experiment and anhydrous particle samples are placed at different positions; The release mechanism releases samples at different positions in a free-fall manner at different times under the control of the control system, and the shooting system outside the tower shoots the samples after release and their collision process.
2. The system according to claim 1, characterized in that: The refrigeration system is a refrigeration compressor installed on the top cover of the drop tower through a vacuum flange, a cold head and a transition piece are installed at the lower end of the vacuum flange, and the sample cavity is connected through the transition piece.
3. The system according to claim 2, characterized in that: Prepare frozen samples as follows: Sample slots are installed at different heights in the sample chamber through a mechanical structure, and the centers of the sample slots at different heights are located on the same axis of the sample chamber; Turn on the refrigeration compressor to reduce the temperature in the sample chamber to below 130K and maintain it stable; Micron-sized atomized droplets are introduced into the sample chamber, where they condense into ice particles and form random ballistic deposition aggregates in the sample trough until the sample size grows to 1.5 to 2 cm.
4. The system according to claim 3, characterized in that: There are two sample slots, and the distance between them ranges from 10 to 20 cm.
5. The system according to claim 3, characterized in that: The anhydrous particle impact test includes two types of experiments: low-speed experiments and high-speed experiments; For the anhydrous particle low-speed collision experiment, sample slots are installed at different heights under the top cover through a mechanical structure, and the centers of the sample slots at different heights are located on the same axis of the vacuum drop tower; there are two sample slots, and the distance between them ranges from 10 to 50 cm; for the anhydrous particle high-speed collision experiment, an ejection mechanism is set at the bottom, and the sample configuration at the top remains unchanged, with a spacing range of 1.5 to 2.0 m.
6. The system according to claim 3 or 5, characterized in that: In low-speed experiments and frozen particle experiments, the sample trough is installed on the release device in a cantilever manner; the release device includes a fixed rod and a rotary solenoid valve; the fixed rod includes a vertical rod and a cross rod, the vertical rod is used to achieve connection with the top cover of the drop tower, the cross rod is fixed on the vertical rod, and the bottom of the cross rod is connected to the sample trough in a cantilever manner through a rotary solenoid valve; when the experiment is required, the rotary solenoid valve is powered off, the sample trough and the cantilever rotate, and the frozen sample on the sample trough falls freely.
7. The system according to claim 5, characterized in that: In the high-speed experiment, the sample trough at the top is installed on the release device by means of a cantilever; the sample trough at the bottom is placed on the ejection mechanism in the vacuum drop tower. The release device allows the anhydrous particles above to fall freely, and the ejection mechanism accelerates the anhydrous particles below upward.
8. The system according to claim 5, characterized in that: The relative speed of low-speed collision test is 0.01~3m / s, and the relative speed of high-speed collision test can reach 5~8m / s.
9. A particle collision dynamics experimental method in a vacuum microgravity environment, characterized by: According to the current pre-experimental content, select the corresponding drop tower top cover. When conducting the anhydrous particle collision experiment, perform the following steps: Select anhydrous particle samples simulating the composition of celestial bodies and load them on the release device; if a low-speed collision experiment is conducted, adjust the distance between the two release devices to the required position; if a high-speed collision experiment is conducted, set up an ejection mechanism at the bottom and load the sample through the release device at the top; Close the top cover of the drop tower and evacuate the inside of the drop tower; The control system controls the release device to release the sample, and the sample collides at a certain relative speed during the free fall process; the camera system moves with the sample outside the drop tower and shoots the collision of the sample through the observation window; When performing a frozen particle collision experiment, perform the following steps: Preparation of frozen particle aggregate samples: adjust the release device spacing; turn on the refrigerator to reduce the temperature in the sample chamber to below 130K and maintain stability; introduce micron-sized atomized droplets into the sample chamber, the droplets condense into ice particles in the sample chamber, and form random ballistic deposition aggregates in the sample slot of the release device until the sample size grows to 1.5-2 cm; Seal the top cover of the drop tower with the vacuum drop tower, and evacuate the inside of the drop tower; The control system controls the release device to release the sample, and the sample collides at a certain relative speed during the free fall process; the high-speed camera moves with the sample outside the drop tower and shoots the sample collision through the observation window.