An experimental system for the whole process of free flow of particle systems in a microgravity environment

Abstract

The present invention belongs to the field of engineering geology, and proposes an experimental system for the whole process of free flow of a particle system in a microgravity environment, including: a structural device, including a bottom connecting plate, a support, and a bearing plate; a flow and slip simulation system, including a fully enclosed slip surface simulation box; a power and recovery system, including a rotating inner plate, a power shaft, an air pump, and a power motor; a data collection and digital control system, including a camera and a microcomputer. Compared with the prior art, the overall structure of the system of the present invention is simple, and it has the advantages of being reusable, fully automated, easy to use, and low in economic cost.

Description

Technical Field

[0001] The present invention belongs to the field of engineering geology, and particularly relates to an experimental system for the free flow of a granular system in a special environment. Background Art

[0002] The gravity effect is of extremely important significance in the field of geotechnical engineering. The fundamental cause of major natural disasters such as landslides is the large-scale and high-speed migration of a granular soil system under the traction of gravity. The gravity levels on the surfaces of extraterrestrial planets such as the moon are much lower than that on the earth's surface. Since the mechanical properties of soil are highly correlated with its stress state, its shear strength, bearing capacity, dilatancy characteristics, deformation characteristics, etc. are all significantly correlated with the effective stress level in the granular system. In a microgravity environment, the self-weight stress of the soil is absent, and the granular system is in an ultra-low confining pressure state. It is still unknown how the soil will behave under such stress conditions, and relevant research needs to be carried out urgently.

[0003] In previous studies, the mechanical properties of the granular soil system in a microgravity environment have been preliminarily studied through experimental means such as drop towers, parabolic aircraft, and microgravity rockets. However, due to the significant characteristics of large scale and long distance in the large deformation flow process of the granular system, it is necessary to conduct continuous observations for a long time to comprehensively capture the energy loss characteristics of the whole process of the granular system flow and obtain the dynamic characteristic parameters of its flow impact. At present, only the experimental conditions provided by the space station can provide long-term observation conditions. On the other hand, the research on the rheological characteristics of the granular system in a variable gravity environment has not been carried out, and it is difficult to quantitatively discuss the influence of gravity conditions on the impact disaster-causing law of the system.

[0004] With the vigorous development of China's aerospace industry, the research on the migration law of the granular system in a microgravity environment has become experimentally feasible. The experimental devices for the granular system in a conventional gravity environment cannot be directly used in microgravity environment experiments, and the main reasons are as follows:

[0005] (1) In the surface environment, the granular system is directly connected to the outside world and lacks a sealed safety system. In a microgravity environment, if not restricted, the escape of particles will cause great harm to the experimental module of the space station.

[0006] (2) For the experiments carried out in the surface environment, the utilization rate of the experimental samples is relatively low. On the earth's surface, it is very convenient for experimenters to operate, so the samples can be easily reloaded after a single group of experiments. However, in space experiments, it is extremely difficult to replace the samples multiple times. On the one hand, it is extremely expensive to transport experimental samples into space; on the other hand, repeatedly disassembling and assembling the samples will significantly increase the risk of particle escape and may cause great harm to the space station.

[0007] (3) In the surface environment, the size limitation of the experimental device and equipment is small. Extremely long flow-sliding channels can be used to simulate the entire process of flow-sliding of the geotechnical particle system over an extremely long distance. However, in the microgravity environment, the size limitation of the experimental device is extremely large. An experimental device as small as possible needs to be used to provide the longest possible channel for the flow-sliding of the geotechnical particle system.

[0008] Therefore, it is necessary to develop a special experimental device for the space microgravity environment to collect the characteristics of the entire process of free flow and impact of the particle system in the microgravity environment. Summary of the Invention

[0009] The purpose of the present invention is to propose a more reasonable and economical experimental system for the entire process of free flow of the particle system in the microgravity environment in view of the deficiencies and problems existing in the prior art.

[0010] The purpose of the present invention can be achieved by the following technical solutions:

[0011] An experimental system for the entire process of free flow of the particle system in the microgravity environment, comprising:

[0012] A structural device, including a bottom connection plate, a support, and a bearing plate;

[0013] A flow-sliding simulation system, including a fully enclosed sliding surface simulation box;

[0014] A power and recovery system, including a rotating inner plate, a power shaft, an air pump, and a power motor;

[0015] A data collection and digital control system, including a camera and a microcomputer.

[0016] Among them:

[0017] Structural device: There are four supports in total, which are respectively installed at the four corners of the bearing plate, used to connect and support the bottom connection plate, and form a containing space between the bearing plate and the bottom connection plate;

[0018] Flow-sliding simulation system: The fully enclosed sliding surface simulation box is a cylindrical fully transparent closed device, the inner side wall of the cylinder is the flow-sliding surface of the particle system, and the fully enclosed sliding surface simulation box is arranged on the supporting bottom connection plate;

[0019] Power and recovery system: The rotating inner plate is located inside the fully enclosed sliding surface simulation box. One end of the rotating inner plate is connected to the power shaft, and the other end is in contact with the inner side wall of the fully enclosed sliding surface simulation box. The upper and lower ends of the rotating inner plate are respectively in contact with the top and bottom of the fully enclosed sliding surface simulation box. The power shaft vertically passes through the center of the bottom of the fully enclosed sliding surface simulation box and is connected to a power motor outside the fully enclosed sliding surface simulation box. The power motor is installed on the bearing plate and is connected to the microcomputer of the data collection and digital control system for driving the power shaft to drive the rotating inner plate to rotate inside the fully enclosed sliding surface simulation box. An air vent pipe is arranged on the rotating inner plate and is connected to an air pump outside the fully enclosed sliding surface simulation box through a pipe. The air pump is installed on the bearing plate and is connected to the microcomputer of the data collection and digital control system.

[0020] Data collection and digital control system: The camera is installed on the rotating inner plate for collecting a series of image features during the flow-sliding process of the geotechnical particle system, and obtaining the flow velocity information of the geotechnical particle system by using existing image processing techniques. The microcomputer is arranged on the bearing plate and is connected to the air pump, the power motor, and the camera at the same time for controlling the movement of the overall system and data collection and transmission.

[0021] Specifically, the rotating inner plate includes an inner plate, a rotating central axis, a transparent guide plate, a soil sample limiting plate, a filter plate, and an internal air vent pipe, where: The head end of the inner plate is fixed to the rotating central axis, the tail end of the inner plate is in contact with the side wall of the fully enclosed sliding surface simulation box, and a soil sample limiting plate is arranged in the middle of the inner plate to divide the inner plate into two sections, namely inner plate section A close to the rotating central axis and inner plate section B close to the side wall of the fully enclosed sliding surface simulation box. A total air vent is arranged at the head end of the inner plate and is connected to the air pump through a pipe. A number of distributed air inlets are arranged in inner plate section B and are connected to the connecting air vent through the internal air vent pipe. The filter plate is arranged at the front end of the distributed air inlets to prevent the air holes from being blocked. The rotating central axis is used to connect to the power shaft. The transparent guide plate is an arc-shaped panel connecting the head end of the inner plate and the tail end of the soil sample limiting plate, thus forming a semi-closed space. The camera is located in this semi-closed space and is installed on the inner plate.

[0022] Furthermore, the flow-sliding simulation system further includes a retaining structure, and the retaining structure is installed on the inner side wall of the fully enclosed sliding surface simulation box. The data collection and digital control system further includes a strain gauge, and the strain gauge is arranged on the retaining structure and is connected to the microcomputer for collecting the impact force characteristic parameters on the surface of the retaining structure and transmitting them to the microcomputer to obtain the impact force time history curve during the impact process.

[0023] Furthermore, the retaining structure is a detachable device, which can be directly removed or its form can be freely replaced according to experimental requirements, such as retaining dams, retaining pile groups, slit dams, etc.

[0024] Furthermore, by turning on the air pump and utilizing the distributed air inlets of the rotating inner plate, a recovery airflow is formed in the fully enclosed sliding surface simulation box, so that the soil particles are gradually gathered in the initial soil sample filling area under the action of the airflow, so as to realize soil sample filling before the experiment and soil sample recovery after the experiment.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] 1. Realize high-precision free flow experiments of particle systems in a microgravity environment and accurately capture the characteristic parameters of the flow and deformation process of the particle system.

[0027] 2. The device is small in size and has a low cost to enter the space station. However, the annular sliding surface (i.e., the inner wall of the cylindrical fully enclosed sliding surface simulation box) can provide a nearly infinite sliding distance, which can simulate the entire process of large deformation flow and sliding of rock and soil particles.

[0028] 3. The device is highly safe, and its fully enclosed structure reduces the risk of particle escape, which can better ensure the safety of the space station experimental cabin.

[0029] 4. The device is equipped with a recovery device, which can recycle samples without releasing the sealed state, greatly improving the reuse rate of samples and effectively reducing experimental costs.

[0030] 5. The overall structure of the experimental system is simple, and the experimental operation can be fully digitized and automated, effectively reducing the workload of aerospace experimental personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is an overall three-dimensional schematic diagram of the experimental system of the embodiment of the present invention;

[0032] Figure 2 A top view of an experimental system according to an embodiment of the present invention;

[0033] Figure 3 This is a disassembled diagram of the detailed structure of the inner panel of the experimental system of the embodiment of the present invention;

[0034] Figure 4 The figure shows a layout scheme of strain gauges according to an embodiment of the present invention.

[0035] Reference numerals:

[0036] Fully enclosed sliding surface simulation box 1, initial soil sample filling area 1-1,

[0037] Rotating inner plate 2, rotating central axis 2-1, transparent guide plate 2-2, soil sample limiting plate 2-3, filter plate 2-4, main airway opening 2-5, internal ventilation duct 2-6, distributed air inlet 2-7, inner plate 2-8, inner plate section A 2-8A, inner plate section B 2-8B,

[0038] Blocking structure 3, power shaft 4, air pump 5, power motor 6,

[0039] Camera 7, strain gauge 8, microcomputer 9,

[0040] Bottom connecting plate 10, support 11, bearing plate 12. Specific implementation mode

[0041] The technical solution provided by the present application will be further described below in conjunction with specific embodiments and their accompanying drawings. In combination with the following description, the advantages and features of the present application will be clearer.

[0042] Embodiment

[0043] The experimental system for the whole process of free flow of the particle system in the microgravity environment of the present application mainly includes a flow-sliding simulation system, a power and recovery system, a data collection and digital control system, and a structural device. The specific structural diagram is shown in Figure 1 and Figure 2 , where:

[0044] The structural device includes a bottom connecting plate 10, a support 11, and a bearing plate 12;

[0045] The flow-sliding simulation system includes a fully enclosed sliding surface simulation box 1 and a blocking structure 3;

[0046] The power and recovery system includes a rotating inner plate 2, a power shaft 4, an air pump 5, and a power motor 6;

[0047] The data collection and digital control system includes a camera 7, a strain gauge 8, and a microcomputer 9.

[0048] Specifically, four supports 11 are installed on the bearing plate 12 to support the bottom connecting plate 10 and form an accommodating gap between the bearing plate 12 and the bottom connecting plate 10; the air pump 5, the power motor 6, and the microcomputer 9 are arranged on the bearing plate 12.

[0049] Specifically, the fully enclosed sliding surface simulation box 1 is a cylindrical fully transparent closed device, and the inner side wall of the cylinder is the flow sliding surface of the particle system; the fully enclosed sliding surface simulation box 1 is arranged on the supporting bottom connecting plate 10, and the blocking structure 3 is installed on the inner side wall of the fully enclosed sliding surface simulation box 1.

[0050] Specifically, the rotating inner plate 2 is located inside the fully enclosed sliding surface simulation box 1. One end of the rotating inner plate 2 is connected to the power shaft 4, and the other end of the rotating inner plate 2 is in contact with the inner side wall of the fully enclosed sliding surface simulation box 1. The upper and lower ends of the rotating inner plate 2 are respectively in contact with the top and bottom of the fully enclosed sliding surface simulation box 1. The power shaft 4 vertically passes through the center of the bottom of the fully enclosed sliding surface simulation box 1 and is connected to a power motor 6 outside the fully enclosed sliding surface simulation box 1. The power motor 6 is used to drive the power shaft 4 to drive the rotating inner plate 2 to rotate inside the fully enclosed sliding surface simulation box 1. An air vent pipe is provided on the rotating inner plate 2 and is connected to an air pump 5 outside the fully enclosed sliding surface simulation box 1 through the pipe.

[0051] Specifically, the camera 7 is installed on the rotating inner plate 2; the strain gauge 8 is arranged on the retaining structure 3; the microcomputer 9 is connected to the air pump 5, the power motor 6, the camera 7, and the strain gauge 8.

[0052] As Figure 3 shown, the rotating inner plate 2 includes an inner plate 2-8, a rotating central axis 2-1, a transparent guide plate 2-2, a soil sample limiting plate 2-3, a filter plate 2-4, and an internal air vent pipe 2-6. Among them: the head end of the inner plate 2-8 is fixed to the rotating central axis 2-1, the tail end of the inner plate 2-8 is in contact with the side wall of the fully enclosed sliding surface simulation box, and a soil sample limiting plate 2-3 is arranged in the middle of the inner plate 2-8 to divide the inner plate 2-8 into two sections, namely an inner plate A section 2-8A close to the rotating central axis and an inner plate B section 2-8B close to the side wall of the fully enclosed sliding surface simulation box; a total air duct opening 2-5 is arranged at the head end of the inner plate 2-8 and is connected to the air pump 5 through a pipe; a plurality of distributed air inlet openings 2-7 are arranged on the inner plate B section 2-8B and are connected to the connecting air duct opening 2-5 through the internal air vent pipe 2-6. The filter plate 2-4 is arranged at the front end of the distributed air inlet opening 2-7 to prevent the air holes from being blocked; the rotating central axis 2-1 is used to be connected to the power shaft 4; the transparent guide plate 2-2 is an arc-shaped panel, connecting the head end of the inner plate 2-8 and the tail end of the soil sample limiting plate 2-3, thus forming a semi-enclosed space. The camera 7 is located in this semi-enclosed space and is installed on the inner plate 2-8.

[0053] The above system can be used for experiments on the entire process of free flow of particle systems in a microgravity environment. The experimental principle and process are as follows:

[0054] In the experimental preparation stage, soil is filled into the initial soil sample filling area 1-1 (located in the inner plate B section 2-8B), as Figure 2As shown. At this time, the air pump remains on, and the soil is preliminarily restricted in the target area by continuous air extraction. After filling, the whole device is kept strictly sealed to prevent the escape of soil particles. Set the experimental conditions according to the experimental requirements, such as the preset speed and rotation distance of the power motor 6. Turn off the air pump at the start of the experiment. The rotating inner plate 2 rotates at a predetermined speed for a predetermined distance under the traction of the power motor 6 through the connection of the power shaft 4. Then the rotating inner plate 2 stops moving, and the soil continues to move due to inertia and is naturally released onto the sliding surface (i.e., the inner wall of the fully enclosed sliding surface simulation box). After the soil freely flows for a predetermined distance, it impacts the retaining structure 3. The characteristic parameters of the surface impact force of the retaining structure 3 are collected using a strain gauge system. Figure 4 Shows a possible design of the layout points of the strain gauges 8, and the arrow direction represents the direction of soil impact. It should be particularly noted that the retaining structure 3 is not an essential component. After it can be removed as a whole, experimental research can be carried out on the characteristics of the ultra-long-distance free-flow sliding of the soil particle system. During the experiment, the movement images of the geotechnical particle flow sliding process are collected by the built-in camera 7. The velocity distribution information throughout the flow sliding process can be obtained using existing image recognition and processing technologies. In this way, a single set of experiments is completed.

[0055] After a single set of experiments, the soil sample is recovered without breaking the airtightness of the device. The usage scheme is as follows: After a single set of experiments is completed, turn on the air pump 5 and continuously extract air. Through the distributed air inlets 2-7, a recovery air flow is formed inside the sliding surface simulation device. Under the action of the air flow, the soil particles will gradually gather in the initial soil sample filling area 1-1. The arc surface of the transparent diversion plate 2-2 can play a guiding role, which is beneficial for the soil particles to return to the initial soil sample filling area 1-1, can improve the recovery rate of the soil sample, and avoid the deposition of the soil sample outside the target area. After all the soil samples are recovered, the rotating inner plate 2 is slowly rotated back to the initial position under the traction of the power motor 6, and then the air pump 5 is turned off to stop air extraction, so that the system can return to the initial state and the next set of experiments can be carried out.

[0056] The above description is only a description of the preferred embodiments of the present application and does not limit the scope of the present application in any way. Any change or modification made by any person skilled in the art based on the disclosed technical content shall be regarded as an equivalent effective embodiment and shall fall within the scope of protection of the technical solution of the present application.

Claims

1. An experimental system for the entire process of free flow of a particle system in a microgravity environment, characterized in that, Comprising: A structural device, including a bottom connecting plate (10), a support (11), and a bearing plate (12); A flow-slip simulation system, including a fully enclosed slip surface simulation box (1); A power and recovery system, including a rotating inner plate (2), a power shaft (4), an air pump (5), and a power motor (6); A data collection and digital control system, including a camera (7) and a microcomputer (9); Wherein: There are four of the supports (11), which are respectively installed at the four corners of the bearing plate (12) for connecting and supporting the bottom connecting plate (10) and forming an accommodation gap between the bearing plate (12) and the bottom connecting plate (10); The fully enclosed slip surface simulation box (1) is a cylindrical fully transparent closed device, and the inner side wall of the cylinder is a flow slip surface of the particle system. The fully enclosed slip surface simulation box (1) is arranged on the supporting bottom connecting plate (10); The rotating inner plate (2) is located inside the fully enclosed slip surface simulation box (1). One end of the rotating inner plate (2) is connected to the power shaft (4), and the other end of the rotating inner plate (2) contacts the inner side wall of the fully enclosed slip surface simulation box (1). The upper and lower ends of the rotating inner plate (2) respectively contact the top and bottom of the fully enclosed slip surface simulation box (1). The power shaft (4) vertically passes through the center of the bottom of the fully enclosed slip surface simulation box (1) and is connected to the power motor (6) outside the fully enclosed slip surface simulation box (1). The power motor (6) is installed on the bearing plate (12) and is connected to the microcomputer (9) of the data collection and digital control system for driving the power shaft (4) to drive the rotating inner plate (2) to rotate inside the fully enclosed slip surface simulation box (1). An air vent pipe is arranged on the rotating inner plate (2) and is connected to the air pump (5) outside the fully enclosed slip surface simulation box (1) through the pipe. The air pump (5) is installed on the bearing plate (12) and is connected to the microcomputer (9) of the data collection and digital control system; The camera (7) is installed on the rotating inner plate (2) for collecting a series of image features during the flow-slip process of the geotechnical particle system, and obtaining the flow velocity information of the geotechnical particle system by using existing image processing techniques. The microcomputer (9) is arranged on the bearing plate (12) and is connected to the air pump (5), the power motor (6), and the camera (7) at the same time for controlling the movement of the overall system and data collection and transmission.

2. The system according to claim 1, wherein The rotating inner plate (2) includes an inner plate (2-8), a rotating central axis (2-1), a transparent guide plate (2-2), a soil sample limiting plate (2-3), a filter plate (2-4), and an internal air vent pipe (2-6), wherein: The first end of the inner plate (2-8) is fixed to the rotating central axis (2-1), and the end of the inner plate (2-8) contacts the side wall of the fully enclosed sliding surface simulation box. A soil sample limiting plate (2-3) is arranged in the middle of the inner plate (2-8) to divide the inner plate (2-8) into two sections, namely, the inner plate section A (2-8A) close to the rotating central axis and the inner plate section B (2-8B) close to the side wall of the fully enclosed sliding surface simulation box; a total air duct opening (2-5) is arranged at the first end of the inner plate (2-8) and is connected to the air pump (5) through a pipeline; a number of distributed air inlets (2-7) are arranged in the inner plate section B (2-8B) and are connected to the connecting air duct opening (2-5) through an internal ventilation pipeline (2-6). The filter plate (2-4) is arranged at the front end of the distributed air inlet (2-7) to prevent the air holes from being blocked; the rotating central axis (2-1) is used to connect to the power shaft (4); the transparent guide plate (2-2) is an arc-shaped panel that connects the first end of the inner plate (2-8) and the end of the soil sample limiting plate (2-3), thus forming a semi-closed space. The camera (7) is located in this semi-closed space and is installed on the inner plate (2-8).

3. The system according to claim 1, wherein The flow and slip simulation system further includes a blocking structure (3), and the blocking structure (3) is installed on the inner side wall of the fully enclosed sliding surface simulation box (1); the data collection and digital control system further includes a strain gauge (8), and the strain gauge (8) is arranged on the blocking structure (3) and is connected to the microcomputer (9) for collecting the impact force characteristic parameters on the surface of the blocking structure (3) and transmitting them to the microcomputer (9) to obtain the impact force time history curve during the impact process.

4. The system according to claim 3, wherein The blocking structure (3) is a detachable device, which can be directly removed or freely replaced according to the experimental requirements.

5. The system according to claim 1, wherein By turning on the air pump and using the distributed air inlets of the rotating inner plate, a recycling air flow is formed in the fully enclosed sliding surface simulation box, so that the soil particles gradually gather in the initial soil sample filling area under the action of the air flow, so as to realize the filling of the soil sample before the experiment and the recycling of the soil sample after the experiment.

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