System and method for measuring excitation speed of simulated lunar dust under vacuum plume action condition

Abstract

The invention discloses a simulation lunar dust excitation speed measurement system and method under a vacuum plume action condition, and relates to the technical field of aerospace engineering, and the system comprises a vacuum chamber and thruster system, an image collection assembly, a synchronous control collection system, a pulse laser light path, a high-speed spotlight, and a simulation lunar surface. In the invention, two optical systems of particle image velocity measurement and particle tracking velocity measurement are integrated in the same experiment, and the 532nm optical filter and the light trapping sheet are configured to realize compatibility of optical requirements, so that the problems that lunar dust particles with different scales and velocities cannot be measured synchronously and the optical systems interfere with each other in the prior art are solved; according to the method, velocity field data of micron-sized high-speed small particles and millimeter-sized low-speed large particles can be synchronously obtained and directly correspond to each other, the measurement integrity and reliability are improved in combination with simulation environment and synchronous control, and accurate data support is provided for spacecraft lunar dust prevention design.

Description

Technical Field

[0001] The present invention relates to the field of aerospace engineering technology, and in particular to a system and method for measuring the agitation velocity of simulated lunar dust under vacuum plume conditions. Background Art

[0002] 1. Brief description of the existing technology:

[0003] When a spacecraft lands or takes off from the lunar surface, the interaction between the engine plume and the lunar surface can stir up lunar dust particles. These particles, upon contact with the spacecraft, can affect sensitive equipment and even cause malfunctions. Measuring the velocity field of lunar dust particles can predict the range and velocity of the dust, as well as its impact on the spacecraft. This can help design more effective landing and takeoff strategies, minimizing damage and impact of lunar dust on equipment. Current methods for measuring lunar dust velocity fields rely primarily on optical measurement techniques, particularly particle image velocimetry (PIV) and particle tracking velocimetry (PTV).

[0004] Particle Image Velocimetry (PIV) is an optical measurement method that adds tracer particles to a fluid or gas. After irradiating it with a pulsed laser, the particle displacement over a short period of time is recorded using a high-speed camera to calculate the velocity distribution. This method is suitable for measuring small particles, typically 1-10 μm in size, and can provide highly accurate velocity distribution data. The PIV measurement process involves first introducing a large number of tiny particles into the flow field, causing them to move with the flow. A pulsed laser is then used to illuminate the area to be measured, and a CCD camera captures two images separated by a small time interval of microseconds. This allows for highly accurate measurement of high-speed particles. Finally, correlation analysis is performed on the images to determine the velocity distribution of the entire measurement area. PIV measurements require that the particles have minimal impact on the flow field, so the smaller the particle size, while still ensuring adequate observation results, is preferred.

[0005] PTV (Particle Tracking Velocimetry) is a fluid dynamics measurement technology based on the particle tracking principle, used to measure the velocity field in the fluid. By adding tiny tracking particles to the fluid and using a high-frame-rate and high-resolution camera to capture the particle's motion trajectory, the velocity information of the fluid is obtained. By analyzing the position information of the particles at different time points, the particle's velocity and acceleration are calculated, and the velocity field distribution at different positions in the fluid is obtained. The high-speed camera system can measure millimeter-scale particles. The shooting method is to continuously capture single images with an interval of milliseconds between images, so it can achieve higher accuracy when measuring low-speed particles.

[0006] 2. Objective shortcomings of existing technologies:

[0007] Existing lunar dust velocity measurement systems have two main shortcomings: they cannot simultaneously measure the motion of particles of different sizes and velocities with high precision, and they cannot meet the optical requirements of two systems at the same time. Specifically,

[0008] 1. The PIV system captures each set of images with a small interval between each image, thus achieving higher accuracy for high-speed, small particles. However, it can only measure the motion of micron-sized particles. High-speed camera systems use continuous shooting, with a large interval between each image, making them suitable for measuring slow-moving, large particles. Current experimental methods typically use two independent measurement systems for separate measurements, making it impossible to simultaneously measure small and large particles. This results in the velocity field data of particles of different particle sizes being unable to directly correspond under the influence of the plume, thus affecting our overall understanding of lunar dust motion.

[0009] 2. PIV requires ensuring that only the tracer particles illuminate the area illuminated by the pulsed laser, while other areas remain as dark as possible to prevent background noise from interfering with particle tracking. High-speed camera systems, on the other hand, require high-brightness background illumination to ensure clear imaging of large particles. However, high-brightness background illumination can cause optical interference in the PIV system, preventing it from capturing high-definition images of the laser-illuminated plume area. Therefore, meeting the requirements of both optical systems in the same experiment is a technical challenge.

[0010] In view of this, a system and method for measuring the agitation velocity of simulated lunar dust under vacuum plume conditions are provided to overcome the above problems. Summary of the Invention

[0011] The purpose of the present invention is to provide a system and method for measuring the agitation velocity of simulated lunar dust under vacuum plume conditions, so as to solve the problems raised in the above background technology.

[0012] To solve the above technical problems, the present invention provides a system for measuring the velocity of simulated lunar dust under vacuum plume conditions, which is characterized by comprising a vacuum chamber and thruster system, an image acquisition component, a synchronous control acquisition system, a pulsed laser optical path, a high-speed spotlight, and a simulated lunar surface;

[0013] The image acquisition components include a PIV dual-frame camera, a PTV high-speed camera, a 532nm filter and a 532nm light trap; the PIV dual-frame camera is equipped with a 532nm filter, and the high-speed spotlight is equipped with a 532nm light trap; the synchronous control acquisition system is used to synchronously control the working timing of the PIV dual-frame camera, PTV high-speed camera, pulse laser and high-speed spotlight.

[0014] Furthermore, the vacuum cabin and thruster system includes a vacuum cabin, a nitrogen cylinder, a monomethylhydrazine storage tank, a dinitrogen tetroxide storage tank, and a thruster; the nitrogen cylinder is connected to the vacuum cabin through a pipeline for regulating the pressure in the cabin; the monomethylhydrazine storage tank and the dinitrogen tetroxide storage tank are connected to the thruster through a fuel pipeline and an oxidizer pipeline, and the thruster is arranged in the vacuum cabin for generating a simulated plume.

[0015] Furthermore, the image acquisition component also includes a dust cover and a transparent glass cover; the PIV dual-frame camera is arranged in the dust cover and connected to the atmosphere through a ventilation pipe to form a normal pressure working environment; the PTV high-speed camera is arranged in the dust cover; the transparent glass cover is sealed and installed at the open end of the dust cover to isolate the vacuum environment and transmit light.

[0016] Furthermore, the synchronous control and acquisition system includes a control collector, a synchronizer, a pulse laser control circuit, and a pulse laser; the control collector is used to set the engine ignition timing and image acquisition parameters; the synchronizer is used to synchronize the working rhythm of the pulse laser, PIV dual-frame camera and PTV high-speed camera.

[0017] Furthermore, the pulse laser optical path includes a reflector and a light guide arm; the pulse laser is arranged outside the vacuum chamber, and the laser is introduced into the vacuum chamber through the reflector and the light guide arm, and the light guide arm can adjust the irradiation position and angle of the laser.

[0018] Furthermore, the high-speed spotlight includes a spotlight body and a 532nm light-trapping plate. The 532nm light-trapping plate cooperates with the spotlight body through threads and is used to filter 532nm wavelength light in the spotlight light source.

[0019] Furthermore, the simulated lunar surface includes a stainless steel tray and simulated lunar dust, and the simulated lunar dust is laid on the surface of the stainless steel tray to simulate the distribution of lunar dust on the lunar surface.

[0020] The method for measuring the agitation velocity of simulated lunar dust under vacuum plume conditions comprises the following steps:

[0021] The simulated lunar dust was laid on a stainless steel tray in the vacuum chamber. The laser was set outside the vacuum chamber and transmitted into the chamber through a light-guiding arm.

[0022] Connect the nitrogen cylinder, monomethylhydrazine storage tank, nitrogen tetroxide storage tank and thruster gas line, and set the engine ignition timing and image acquisition parameters through the synchronous control acquisition system;

[0023] Install a 532nm filter on the PIV dual-frame camera to allow the lens to only pass 532nm wavelength light; install a 532nm light trap on the high-speed spotlight to filter out 532nm wavelength light;

[0024] The thrusters were activated to generate plumes, stirring up simulated lunar dust. A pulsed laser emitted a thin sheet of 532nm laser light to illuminate the flow field area to be measured. A PIV dual-frame camera captured displacement images of tracer particles at microsecond intervals, while a PTV high-speed camera continuously captured the motion trajectories of large particles at millisecond intervals.

[0025] The image data collected by the PIV dual-frame camera and the PTV high-speed camera were analyzed to calculate the velocity field distribution of lunar dust particles of different sizes.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] Synchronous measurement of particles of different scales and speeds: By integrating two optical systems, a PIV dual-frame camera and a PTV high-speed camera, in the same experiment, the synchronous measurement of small particles at the micron level (1-10μm) and large particles at the millimeter level can be achieved. This enables direct correspondence between the velocity field data of particles of different sizes, solving the problem of two independent systems being unable to make synchronous measurements in existing technologies, and providing correlated data support for the overall analysis of lunar dust movement.

[0028] Compatible with the lighting requirements of the two optical systems: By assembling a 532nm filter on the PIV dual-frame camera, only the 532nm wavelength light of the pulsed laser is allowed to pass through, ensuring that the PIV system only receives the tracer particle signal in the laser irradiation area; at the same time, a 532nm light trap is installed on the high-speed spotlight to filter out the 532nm wavelength light in the spotlight light source to avoid optical interference with the PIV system, allowing the PTV high-speed camera to clearly image under a high-brightness background, achieving compatibility between the two optical systems in the same experimental environment.

[0029] Improving the integrity of lunar dust motion analysis: Synchronously acquiring velocity distribution data for particles of different sizes avoids data fragmentation caused by independent measurements, helping researchers to more comprehensively understand the motion patterns of lunar dust particles under the action of plumes, including the velocity differences, distribution ranges, and interactions of particles of different sizes, providing a more accurate basis for the design of spacecraft to protect against lunar dust.

[0030] Optimizing the optical measurement environment: The PIV dual-frame camera maintains a normal-pressure operating environment through a dust cover and ventilation duct, ensuring stable operation within the vacuum chamber. The pulsed laser is located outside the chamber, and the position and angle of the laser are flexibly adjusted using a light-guide arm and reflector, enabling all-around illumination of the test area within the vacuum chamber, enhancing the reliability and flexibility of the measurement system.

[0031] Solving the technical problem of optical interference: The combination of a 532nm filter and a light trap eliminates the interference of PTV high-brightness illumination on the PIV system at the hardware level. This allows the two measurement technologies to operate synchronously within the same experimental sequence, eliminating the need for time-sharing operation, improving experimental efficiency and ensuring temporal consistency of data.

[0032] Precisely matching the characteristics of lunar dust particles: The simulated lunar surface uses a stainless steel tray and simulated lunar dust. Its particle size, shape, density and other parameters are close to those of real lunar dust. Combined with the plume simulation environment in the vacuum chamber, it can effectively reproduce the scene of lunar dust stirring on the lunar surface, making the measurement results closer to actual working conditions and enhancing the engineering application value of the experimental data.

[0033] Integrated system design: The synchronous control and acquisition system coordinates engine ignition timing, laser emission frequency, camera shooting parameters, etc., ensuring the precise synchronization of the working rhythm of each device, avoiding the timing deviation that may be caused by independent control, and improving the accuracy and reliability of measurement data.

[0034] Promote the optimization of spacecraft anti-lunar dust design: By obtaining the velocity field distribution of lunar dust particles of different sizes, the spacecraft surface protection structure, equipment layout and take-off and landing strategy can be improved in a targeted manner, reducing the impact and wear of lunar dust on sensitive equipment, and providing technical support for the safety and reliability of lunar exploration missions. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of the overall system of the system and method for measuring the agitation velocity of simulated lunar dust under vacuum plume conditions of the present invention;

[0036] Figure 2 Schematic diagram of the structure of the PIV acquisition component in the system and method for measuring the velocity of simulated lunar dust under vacuum plume conditions of the present invention;

[0037] Figure 3 A schematic diagram of the high-speed spotlight structure in the system and method for measuring the agitation velocity of simulated lunar dust under vacuum plume conditions of the present invention;

[0038] Figure 4 Schematic diagram of the simulated lunar surface in the system and method for measuring the agitation velocity of simulated lunar dust under vacuum plume conditions of the present invention.

[0039] In the picture:

[0040] Vacuum chamber and thruster system 1, image acquisition component 2, synchronous control acquisition system 3, pulse laser optical path 4, high-speed spotlight 5a, high-speed spotlight 5b, simulated lunar surface 6;

[0041] The vacuum chamber and thruster system 1 includes a vacuum chamber 101, a nitrogen cylinder 102a, a nitrogen cylinder 102b, a monomethylhydrazine storage tank 103, a fuel pipeline 104, a nitrogen tetroxide storage tank 105, an oxidant pipeline 106, a through-chamber flange 107a, a through-chamber flange 107b, a through-chamber flange 107c, and a thruster 108.

[0042] The image acquisition assembly 2 includes a transparent glass cover 201, a dust cover 202a, a dust cover 202b, a PIV dual-frame camera 203, a 532nm filter 204, a ventilation tube 205a, a ventilation line 205b, and a PTV high-speed camera 206;

[0043] The synchronous control and acquisition system 3 includes a control and acquisition device 301, a synchronizer 302, a pulse laser control circuit 303, a pulse laser 304, a PIV double-frame camera control circuit 305, a PIV double-frame camera acquisition circuit 306, and a PTV high-speed camera control and acquisition circuit 307;

[0044] The pulse laser optical path 4 includes a reflector 401a, a reflector 402b, and a light guide arm 403;

[0045] The high-speed spotlight 5a includes a spotlight body 501a, a 532nm light trap 502a, and a spotlight power cord 503a;

[0046] The simulated lunar surface 6 includes a stainless steel tray 601 and simulated lunar dust 602 . DETAILED DESCRIPTION

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0048] During spacecraft exploration of the Moon, lunar dust poses a serious threat to the normal operation of spacecraft equipment. During landing and takeoff, the interaction of the engine plume with the lunar surface stirs up lunar dust particles. Upon contact with the spacecraft, this dust can affect sensitive equipment and even cause malfunctions. To effectively address this issue, accurately measuring the velocity field of lunar dust particles is crucial. This helps researchers predict the range and velocity of the dust, as well as its impact on spacecraft, enabling them to design more effective landing and takeoff strategies, minimizing damage to equipment.

[0049] See also Figure 1-Figure 4 ,,The present invention provides a technical solution:

[0050] See Figure 1-Figure 4 As shown, an embodiment of the system and method for measuring the velocity of lunar dust under vacuum plume conditions:

[0051] 1. Measurement system composition:

[0052] The measurement system mainly consists of a vacuum chamber and thruster system 1, an image acquisition component 2, a synchronous control acquisition system 3, a pulsed laser optical path 4, high-speed spotlights 5a and 5b, and a simulated lunar surface 6.

[0053] Vacuum Chamber and Thruster System: This system functions as a "space environment simulation factory," primarily comprising a vacuum chamber 101, nitrogen cylinders 102a and 102b, a monomethylhydrazine tank 103, fuel lines 104, a nitrogen tetroxide tank 105, an oxidizer line 106, through-chamber flanges 107a, 107b, and 107c, and a thruster 108. The vacuum chamber 101 is the core of the entire experiment, simulating the vacuum environment of the lunar surface and providing realistic conditions for the lunar dust agitation experiment. Nitrogen cylinders 102a and 102b each store a certain amount of nitrogen. During the experiment, this nitrogen acts as an auxiliary gas to regulate the pressure within the vacuum chamber and ensure stability. The monomethylhydrazine tank 103 and the nitrogen tetroxide tank 105 store the monomethylhydrazine fuel and the nitrogen tetroxide oxidizer, respectively. They are connected to the thruster 108 via the fuel line 104 and the oxidizer line 106. When the experiment begins, monomethylhydrazine and nitrogen tetroxide mix and burn in thruster 108, creating an effect similar to a spacecraft engine plume. This plume acts on the simulated lunar surface, stirring up lunar dust particles. Through-cabin flanges 107a, 107b, and 107c play a key role in connection and sealing, ensuring the vacuum environment within the vacuum chamber is not disrupted. They also allow various external pipes and lines to be smoothly connected to the vacuum chamber, enabling coordinated operation between the various components of the system.

[0054] Image acquisition assembly: Image acquisition assembly 2 acts as the "eyes" of the experiment, consisting of a transparent glass cover 201, dust covers 202a and 202b, a PIV dual-frame camera 203, a 532nm filter 204, a vent tube 205a, a vent line 205b, and a PTV high-speed camera 206. The transparent glass cover 201 is installed at the opening of the vacuum chamber 101. It not only withstands the pressure difference between the inside and outside of the vacuum chamber, ensuring the stability of the vacuum environment, but also possesses excellent optical properties, enabling the camera to clearly capture the experimental conditions within the chamber. Dust covers 202a and 202b provide additional protection for the PIV dual-frame camera 203 and PTV high-speed camera 206, preventing lunar dust particles from entering the cameras and affecting their normal operation. The PIV dual-frame camera 203 is housed within the dust cover 202a. It is connected to the atmosphere via a ventilation line 205a, creating an atmospheric pressure environment within the protective cover, like a comfortable "little room" for the camera, ensuring the normal operation of the PIV dual-frame camera 203 within the vacuum chamber. A 532nm filter 204, tightly coupled to the PIV dual-frame camera 203 via the lens mount, allows only light of 532nm to pass through, effectively filtering out other wavelengths and improving image quality. A PTV high-speed camera 206, mounted within the dust cover 202b, is responsible for capturing the movement of large particles.

[0055] Synchronous Control and Acquisition System: The synchronous control and acquisition system 3 is the "brain" of the entire measurement system, comprising a control and acquisition unit 301, a synchronizer 302, a pulsed laser control circuit 303, a pulsed laser 304, a PIV dual-frame camera control circuit 305, a PIV dual-frame camera acquisition circuit 306, and a PTV high-speed camera control and acquisition circuit 307. The control and acquisition unit 301 acts as the overall commander, coordinating the operations of various devices and setting experimental parameters such as engine ignition timing and image acquisition intervals. The synchronizer 302 ensures precise synchronization between the various devices, guaranteeing the accuracy of the experimental data. The pulsed laser control circuit 303 controls the emission frequency and energy of the pulsed laser 304, ensuring that it emits a laser beam that meets experimental requirements. The PIV dual-frame camera control circuit 305 and the PIV dual-frame camera acquisition circuit 306 respectively control the PIV dual-frame camera 203's image capture and image acquisition processes, ensuring that the camera accurately records the displacement information of the tracer particles. The PTV high-speed camera control and acquisition circuit 307 is responsible for controlling the PTV high-speed camera 206 and acquiring images.

[0056] Pulsed laser optical path: Pulsed laser optical path 4 is like a laser "highway," consisting of reflectors 401a, 401b, and a light-guiding arm 403. The laser is located outside the vacuum chamber to prevent the vacuum environment from adversely affecting its operation. Light-guiding arm 403, located within the chamber, acts like a flexible "arm," transmitting the laser beam and, by adjusting its position and angle, providing all-round, multi-angle illumination of the part to be measured within the chamber. Reflectors 401a and 401b are used to change the propagation direction of the laser beam, ensuring that the laser accurately illuminates the area to be measured.

[0057] High-speed spotlights: High-speed spotlights 5a and 5b are used to illuminate the plume area for PTV high-speed camera imaging. High-speed spotlight 5a consists of a spotlight body 501a, a 532nm light-trapping plate 502a, and a power cord 503a. The 532nm light-trapping plate 502a threads tightly into the spotlight body 501a, filtering out the 532nm wavelength of light from the spotlight source to prevent interference with the PIV dual-frame camera while ensuring that the PTV high-speed camera can clearly capture the illuminated plume area.

[0058] Simulated lunar surface: Simulated lunar surface 6 consists of a stainless steel tray 601 and simulated lunar dust 602. Stainless steel tray 601 serves as a carrier for simulated lunar dust 602. Its smooth surface simulates some of the lunar surface's characteristics. Simulated lunar dust 602 is specially prepared based on the properties of lunar dust, with particle size, shape, density, and other parameters similar to those of real lunar dust. It is used to simulate the agitation of lunar dust by the plume during the experiment.

[0059] 2. Measurement system workflow:

[0060] During the experimental preparation phase, researchers first evenly spread simulated lunar dust 602 onto a stainless steel tray 601 to simulate the distribution of lunar dust on the lunar surface. The assembled simulated lunar surface 6 was then placed into a vacuum chamber 101. Next, the laser was installed in a suitable location outside the chamber and the light guide arm 403 in the pulsed laser optical path 4 was connected to ensure smooth transmission of the laser beam into the chamber. Furthermore, the connections of all equipment were carefully checked to ensure that the air and electrical circuits were securely connected and free of leaks and looseness.

[0061] Gas line connection and timing setting: Connect the gas lines between nitrogen cylinders 102a and 102b, monomethylhydrazine storage tank 103, dinitrogen tetroxide storage tank 105, and thruster 108 to ensure smooth gas flow. Use the synchronous control and acquisition system 3 to set the engine ignition and image acquisition timing. For example, set the engine ignition preparation time to 10 seconds, the ignition duration to 5 seconds, image acquisition to start 1 second before engine ignition and continue 5 seconds after engine ignition. The sampling interval of the PIV dual-frame camera 203 is 10 microseconds, and the frame rate of the PTV high-speed camera 206 is 1000 frames per second.

[0062] Optical system debugging and measurement: The 532nm filter 204 is accurately mounted on the PIV dual-frame camera 203. At this point, the lens of the PIV dual-frame camera 203 only allows light with a wavelength of 532nm to pass through. The pulsed laser 304 is turned on, emitting a thin 532nm laser beam to illuminate the plume area to be tested. The PIV dual-frame camera 203 captures the positional changes of the tracer particles in the flow field across two images at the set sampling interval. Simultaneously, a 532nm light trap 502a is mounted on the constantly illuminated high-speed spotlight 5a to filter out the 532nm wavelength light from the spotlight source, allowing the illuminated plume area to be clearly captured by the PTV high-speed camera 206 while avoiding interference with the PIV dual-frame camera 203. In this way, the requirements of both the PIV and PTV optical systems are met in the same experiment.

[0063] Lunar dust agitation and velocity measurement: The thruster 108 is activated, and monomethylhydrazine and nitrogen tetroxide mix and burn within the thruster, generating a plume that impacts the lunar dust on the simulated lunar surface 6. The impact of the plume on the lunar dust stirs up particles of varying sizes. A pulsed laser 304 emits multiple cylindrical laser beams, which are modulated into a thin sheet of laser light by a light sheet generator to illuminate the flow field area to be measured. A PIV dual-frame camera 203 and a PTV high-speed camera 206 operate simultaneously in a direction perpendicular to the laser sheet. The PIV dual-frame camera 203 captures the positional changes of tracer particles in the flow field across two images and calculates the instantaneous velocity of the fluid particle at the tracer particle within the flow field at the sampling moment. This is suitable for measuring the velocity of small particles in the micron range. The PTV high-speed camera 206 continuously captures single images, recording the motion trajectory of larger particles. By analyzing the positional information of the large particles at different time points, the velocity and acceleration of the large particles are calculated, thereby obtaining the velocity field distribution of the large particles at different locations.

[0064] Data Processing and Analysis: After the experiment, researchers retrieved image data from the PIV dual-frame camera 203 and the PTV high-speed camera 206. Using specialized data processing software, they performed correlation analysis on the PIV dual-frame images to obtain velocity distribution data for micron-sized particles. Particle tracking analysis was performed on the PTV high-speed camera images to obtain motion trajectories and velocity information for larger particles. By integrating and comparing the data from the two cameras, they gained a comprehensive understanding of the velocity distribution of lunar dust particles of varying speeds and sizes, providing robust data support for studying the motion patterns of lunar dust particles.

[0065] The measurement system and method described in this embodiment successfully address the existing challenges of simultaneously and accurately measuring the motion of particles of varying sizes and velocities, as well as the inability to simultaneously meet the optical requirements of two systems. Using two optical systems in the same experiment enables simultaneous measurement of the velocity distribution of particles of varying sizes and velocities. The velocity field data for particles of varying sizes can be directly correlated, helping researchers gain a deeper understanding of the overall characteristics of lunar dust motion and providing crucial technical support for the safe landing and takeoff of spacecraft on the lunar surface.

Claims

1. A system for measuring the velocity of simulated lunar dust under vacuum plume conditions, characterized by: It includes a vacuum chamber and thruster system (1), an image acquisition component (2), a synchronous control acquisition system (3), a pulse laser optical path (4), high-speed spotlights (5a, 5b), and a simulated lunar surface (6); The image acquisition component (2) includes a PIV double-frame camera (203), a PTV high-speed camera (206), a 532nm filter (204) and a 532nm light trap (502a); the PIV double-frame camera (203) is equipped with a 532nm filter (204), and the high-speed spotlights (5a, 5b) are equipped with a 532nm light trap (502a); and the synchronous control acquisition system (3) is used for synchronously controlling the working sequence of the PIV double-frame camera (203), the PTV high-speed camera (206), the pulse laser (304) and the high-speed spotlights (5a, 5b).

2. The system for measuring the velocity of simulated lunar dust under vacuum plume conditions as claimed in claim 1, characterized in that: The vacuum chamber and thruster system (1) comprises a vacuum chamber (101), nitrogen cylinders (102a, 102b), a monomethylhydrazine storage tank (103), a dinitrogen tetroxide storage tank (105), and a thruster (108); the nitrogen cylinders (102a, 102b) are connected to the vacuum chamber (101) through pipelines for regulating the pressure in the chamber; the monomethylhydrazine storage tank (103) and the dinitrogen tetroxide storage tank (105) are connected to the thruster (108) through a fuel pipeline (104) and an oxidant pipeline (106); the thruster (108) is arranged in the vacuum chamber (101) for generating a simulated plume.

3. The system for measuring the velocity of simulated lunar dust under vacuum plume conditions as claimed in claim 1, characterized in that: The image acquisition assembly (2) further comprises a dust cover (202a, 202b) and a transparent glass cover plate (201); a PIV double-frame camera (203) is arranged in the dust cover (202a) and communicates with the atmosphere via a ventilation pipe (205a) to form a normal pressure working environment; a PTV high-speed camera (206) is arranged in the dust cover (202b); and the transparent glass cover plate (201) is sealed and mounted on the open ends of the dust covers (202a, 202b) to isolate the vacuum environment and transmit light.

4. The system for measuring the velocity of simulated lunar dust under vacuum plume conditions as claimed in claim 1, characterized in that: The synchronous control acquisition system (3) comprises a control acquisition device (301), a synchronizer (302), a pulse laser control circuit (303), and a pulse laser (304); the control acquisition device (301) is used to set the engine ignition timing and image acquisition parameters; and the synchronizer (302) is used to synchronize the working rhythm of the pulse laser (304), the PIV double-frame camera (203), and the PTV high-speed camera (206).

5. The system for measuring the velocity of simulated lunar dust under vacuum plume conditions as claimed in claim 1, characterized in that: The pulse laser optical path (4) comprises reflectors (401a, 401b) and a light guide arm (403); the pulse laser (304) is arranged outside the vacuum chamber (101), and the laser is guided into the vacuum chamber (101) via the reflectors (401a, 401b) and the light guide arm (403); the light guide arm (403) can adjust the irradiation position and angle of the laser.

6. The system for measuring the velocity of simulated lunar dust under vacuum plume conditions as claimed in claim 1, characterized in that: The high-speed spotlight (5a, 5b) comprises a spotlight body (501a) and a 532nm light-trapping plate (502a); the 532nm light-trapping plate (502a) cooperates with the spotlight body (501a) via a thread and is used to filter light with a 532nm wavelength in the spotlight light source.

7. The system for measuring the velocity of simulated lunar dust under vacuum plume conditions as claimed in claim 1, characterized in that: The simulated lunar surface (6) comprises a stainless steel tray (601) and simulated lunar dust (602), wherein the simulated lunar dust (602) is laid on the surface of the stainless steel tray (601) to simulate the distribution of lunar dust on the lunar surface.

8. A method for measuring the velocity of simulated lunar dust under vacuum plume conditions, characterized in that: The following steps are involved: Simulated moon dust (602) is laid on a stainless steel tray (601) in a vacuum chamber (101), a laser is set outside the vacuum chamber (101), and laser light is transmitted into the chamber through a light guide arm (403); Connecting the nitrogen cylinders (102a, 102b), the monomethylhydrazine storage tank (103), the nitrogen tetroxide storage tank (105) and the gas path of the thruster (108), and setting the engine ignition timing and image acquisition parameters through the synchronous control acquisition system (3); Assembling a 532nm filter (204) on the PIV dual-frame camera (203) so that the lens only passes light with a wavelength of 532nm; Assembling a 532nm light trap (502a) on the high-speed spotlights (5a, 5b) to filter light with a wavelength of 532nm; The thruster (108) is started to generate a plume, stirring up the simulated lunar dust (602); the pulse laser (304) emits a 532nm thin-sheet laser to illuminate the flow field area to be measured, the PIV double-frame camera (203) collects the displacement image of the tracer particles at microsecond intervals, and the PTV high-speed camera (206) continuously captures the motion trajectory of large particles at millisecond intervals; The image data collected by the PIV double-frame camera (203) and the PTV high-speed camera (206) are analyzed to calculate the velocity field distribution of lunar dust particles of different sizes.

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