A physical simulation method for the formation process of lunar lava tube structures

Abstract

This invention relates to the field of physical similarity simulation technology, specifically providing a physical simulation method for the formation process of lunar lava tube structures. The method involves preparing a simulated melt that meets the rheological and thermodynamic similarity criteria of basaltic lava by mixing thermoplastic materials with condensation additives. The low-gravity effect, high-vacuum environment, and radiative cooling conditions under lunar conditions are reproduced using inclined flow channels and thermal vacuum cavities. By precisely matching dimensionless parameters such as Peckley number, dimensional temperature, and Rayleigh number, the injection rate, flow channel inclination angle, and target ambient temperature of the simulated melt are determined. Under these conditions, controlled melt flow and surface solidification crust formation are simulated, ultimately forming a cavity structure model. This allows for the physical study of the formation process of lunar lava tube structures. This invention can accurately reproduce the dynamic crust formation and cavity formation process of lava flow under extreme lunar conditions, providing a quantitative experimental data basis for the study of the formation mechanism of lunar lava tubes and their engineering applications.

Description

Technical Field

[0001] This invention belongs to the field of physical similarity simulation technology, and in particular relates to a physical simulation method for the formation process of lunar lava tube structures. Background Technology

[0002] Lunar lava tubes, due to their unique natural underground tunnel structure, are considered ideal sites for future permanent lunar research stations or habitats. The lunar surface environment is extremely harsh, facing intense cosmic rays (GCR), solar particle events (SPE), dramatic diurnal temperature variations (approximately -233°C to 123°C), and frequent micrometeoroid impacts. The thick layer of lunar regolith on the top of the lava tubes provides effective radiation shielding and physical protection against meteoroids. More importantly, the high thermal inertia of the underground environment maintains a near-constant temperature, a stark contrast to the extreme temperature fluctuations on the lunar surface, significantly reducing the base's dependence on complex energy and thermal management systems. Therefore, in-depth research into the formation process of lunar lava tubes is a major engineering requirement for selecting sites for permanent lunar bases.

[0003] The estimated size of lunar lava tubes far exceeds that of Earth. Typical diameters of Earth's lava tubes range from 10 to 30 meters, with the longest recorded at 65.5 kilometers. However, the low gravity (approximately 1 / 6 G) and high volumetric flow rate of the lunar environment suggest that lunar lava tubes could have diameters ranging from 500 to 1100 meters, and even, based on gravity data, widths of 1 to 2 kilometers. This enormous difference in scale directly reflects the differences in planetary environmental parameters.

[0004] The formation mechanism of lunar lava tubes involves the cooling process of low-viscosity basaltic lava flows, during which the surface solidifies to form a crust, while the internal lava flow empties, creating a cavity. Thermal erosion is an indispensable higher-order process for explaining the formation of large lava tubes on Earth (such as the 21-meter-wide, 18-meter-high Kazumura Cave in Hawaii) and giant tubes on the Moon. High-speed, continuous, high-temperature magma flows continuously expand the width and depth of the channels by melting and eroding the underlying rock. Planetary science analysis indicates that for lunar lava tubes to reach spans of hundreds of meters or even kilometers, the magma flow must form such enormous channels within a limited eruption time through an efficient thermal erosion mechanism. Therefore, quantitative physical process modeling and experimental verification of the dynamic flow, crusting, and thermal erosion processes of lava flows in the lunar environment is a key scientific bottleneck in current research.

[0005] However, existing rock pipe simulation technologies have significant limitations:

[0006] Existing numerical models of lava flow and cooling are mostly derived from Earth's volcanic scenarios and are difficult to apply directly to the lunar environment under low gravity, extreme temperature differences, and high vacuum conditions. These models lack an accurate description of the coupling mechanism of the heat-fluid-mechanical fields, especially in the high vacuum environment of the Moon, where heat loss is mainly dominated by radiative cooling rather than convection as on Earth.

[0007] Traditional ground-based physical simulations, even using similar materials such as paraffin, cannot accurately reproduce the low-gravity fluid effects and high-vacuum environment of the Moon simultaneously in a laboratory setting. This decoupling of fluid dynamics (controlled by Pe and Ra numbers) from the radiative cooling mechanism (controlled by dimensional temperature θ) results in significant physical distortions in the simulations of crust formation rates, crust thickness, and the dynamic equilibrium between thermal erosion and crust formation.

[0008] Furthermore, the simulated structural morphology is mostly qualitative, lacking high-resolution, detailed geometric data that can be used for downstream structural engineering assessment. Summary of the Invention

[0009] In view of this, the present invention aims to provide a physical simulation method for the formation process of lunar lava tube structures. Based on similarity theory, the inclination angle of the flow channel, the injection rate of the simulated melt, and the target ambient temperature are determined. The method performs integrated coupled simulation of the lunar low-gravity fluid effect, high vacuum environment, and precise radiation cooling conditions, overcoming the shortcomings of existing simulation technologies in reproducing the fluid dynamics and heat conduction mechanisms under the extreme environment of the moon.

[0010] To achieve the above objectives, the technical solution created by this invention is implemented as follows:

[0011] This invention provides a physical simulation method for the formation process of lunar lava tube structures, comprising:

[0012] S1: Prepare a simulated melt by mixing thermoplastic materials with condensation additives;

[0013] S2: The flow channel is placed in a hot vacuum cavity, wherein the tilt angle of the flow channel is adjustable, and the tilt angle of the flow channel is designed to simulate the gravitational acceleration of the moon.

[0014] S3: With the goal of matching the dimensionless numbers of Peckled number, dimensional temperature, and Rayleigh number in the actual formation process of the lunar lava tube structure with the Peckled number, dimensional temperature, and Rayleigh number in the physical simulation of the lunar lava tube structure, the inclination angle of the flow channel, the injection rate of the simulated melt, and the target ambient temperature are determined by inversion based on the physical property parameters of the simulated melt.

[0015] S4: Adjust the air pressure inside the thermal vacuum cavity to the actual air pressure on the moon, and adjust the temperature of the flow channel to the target ambient temperature;

[0016] S5: Inject the simulated melt into the flow channel according to the injection rate of the flow channel, and monitor the shell thickness of the simulated melt in the flow channel;

[0017] S6: When the thickness of the shell reaches the preset critical thickness, the injection of the simulated melt is terminated, and the simulated melt remaining in the flow channel is emptied to obtain a cavity structure model.

[0018] S7: Use a high-resolution 3D scanning device to perform a 3D scan on the cavity structure model, and construct a lunar lava tube structure model based on the scanning parameters.

[0019] Preferably, the thermoplastic material is paraffin wax, and the condensing additive is 1500-mesh talc powder.

[0020] Preferably, the mixing ratio of 1500 mesh talc is 10% to 25%.

[0021] Preferably, the goal is to match the dimensionless numbers of the Pelet number, dimensional temperature, and Rayleigh number in the actual formation process of the lunar lava tube structure with the Pelet number, dimensional temperature, and Rayleigh number in the physical simulation of the lunar lava tube structure. This includes setting the Pelet number, dimensional temperature, and Rayleigh number in the physical simulation of the lunar lava tube structure to be equal to the Pelet number, dimensional temperature, and Rayleigh number in the actual formation process of the lunar lava tube structure.

[0022] Preferably, the function expression for the Peckle number is:

[0023] ;

[0024] in, Where is the Peckle number, U represents the flow velocity of the simulated melt, L represents the characteristic length, and k represents the thermal diffusivity;

[0025] The functional expression for dimensional temperature is:

[0026] ;

[0027] in, Temperature in a dimension This indicates the initial temperature of the simulated melt. Indicates the target ambient temperature. Indicates the solidification temperature of the simulated melt;

[0028] The functional expression for Rayleigh numbers is:

[0029] ;

[0030] in, For Rayleigh numbers, This represents the Earth's gravitational acceleration. Indicates the coefficient of volume expansion. Indicates characteristic temperature difference, Indicates the thickness of the crust. This indicates the viscosity of the simulated melt.

[0031] Preferably, the inclination angle of the flow channel satisfy:

[0032] ;

[0033] in, This represents the effective gravitational acceleration component along the inclined direction of the flow channel. The value is taken as the lunar gravitational acceleration.

[0034] Preferably, the relationship between the Pelet number used to control the formation rate of the crust boundary of the simulated melt and the forward movement rate of the simulated melt is the same as that in the actual formation process of the lunar lava tube structure;

[0035] The dimensional temperature is used to control the critical conditions for crust formation of the simulated melt, which is the same as the actual formation process of lunar lava tube structures.

[0036] The Rayleigh number is used to control the flow state of the simulated melt, which is the same as the actual formation process of the lunar lava tube structure.

[0037] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0038] This invention features an innovative design for the simulated material system. Based on traditional pure paraffin wax, 1500-mesh talc powder is added as a condensation additive. The talc powder particles effectively promote the heterogeneous nucleation process of the paraffin wax melt and accelerate the shell formation rate of the melt, enabling it to form a solid shell more quickly and uniformly under vacuum radiation cooling conditions. This solves the defects of traditional pure paraffin wax, such as slow solidification, significant shrinkage, and difficulty in forming a complete cavity.

[0039] This invention is the first to integrate and couple low-gravity fluid effects (simulated by tilt angle α), high vacuum environment (achieved through TVC), and precise radiative cooling conditions (precisely controlled by target ambient temperature) in an experiment, ensuring the physical rationality of the simulation environment. By matching Peckley number, dimensional temperature, and Rayleigh number, it achieves quantitative control over the heat transfer, flow, and crusting dynamics of the simulated melt, making it as close as possible to the actual formation process of lunar lava tube structures. This solves the problem of distortion in the crusting rate of existing models when describing pure radiative cooling on the moon.

[0040] The final output model of this invention, through high-resolution 3D scanning, can achieve an overall reconstruction accuracy better than 1 cm, providing reliable geometric data for subsequent engineering structural stability assessment. Attached Figure Description

[0041] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0042] Figure 1 This is a flowchart of a physical simulation method for the formation process of a lunar lava tube structure according to an embodiment of the present invention. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and do not constitute a limitation thereof. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the invention. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, some operations related to the invention are not shown or described in the specification. This is to avoid obscuring the core parts of the invention with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; the relevant operations can be fully understood based on the description in the specification and general technical knowledge in the art.

[0044] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined to form various implementations. Furthermore, the order of the steps or actions in the method description can be changed or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various orders in the specification and drawings are merely for the clear description of a particular embodiment and do not imply a mandatory order, unless otherwise stated that a particular order must be followed.

[0045] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0046] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0047] The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0048] Please see Figure 1 In one embodiment of the present invention, a physical simulation method for the formation process of lunar lava tube structures is provided. This method simulates the formation process of lunar lava tubes (LLTs) under low gravity, high vacuum, and extreme thermal radiation conditions on the moon in a controlled terrestrial experimental environment. This provides a quantitative and verifiable experimental method for elucidating the formation mechanism of lunar lava tubes and establishing engineering evaluation indicators. The physical simulation method specifically includes the following steps:

[0049] S1: Pretreatment of the simulated material system: A simulated melt is prepared by mixing thermoplastic materials with a condensation additive. In this embodiment of the invention, paraffin wax is used as the thermoplastic material. Paraffin wax has thermoplasticity and a controllable freezing point, and its use as a base simulated melt is suitable for conducting phase change flow experiments under laboratory conditions.

[0050] Because pure paraffin wax exhibits slow solidification, significant shrinkage, and difficulty in forming complete cavities during cooling, this invention innovatively incorporates 1500-mesh ultrafine talc powder as a condensation additive into the paraffin wax melt. The talc powder and paraffin wax are thoroughly mixed in a specific ratio to prepare a simulated melt. The 1500-mesh talc powder serves as a condensation nucleus, with a mass ratio ranging from 10% to 25%, accelerating the heterogeneous nucleation process of the simulated melt under vacuum thermal conditions. This accelerates the crust formation rate of the melt, enabling it to form a more rapid and uniform solid outer shell under vacuum radiative cooling conditions, indirectly simulating the efficient crust formation mechanism of lava flows in a lunar environment.

[0051] In addition, the mass ratio of talc can effectively adjust the effective viscosity of the simulated melt. By adjusting the thermal conductivity, the similarity requirements of the Pecklet and Rayleigh numbers of the simulated melt and actual lunar lava can be accurately matched, making the simulated melt more closely resemble lunar lava. By adjusting the effective viscosity, the flow inertia of the simulated melt can be effectively adjusted on an experimental scale, helping the flow state to transition from turbulent to laminar flow more quickly and ensuring stable crust formation.

[0052] S2: Environmental Coupling System Construction: The flow channel is placed within a thermal vacuum chamber. The inclination angle of the flow channel is adjustable, and its design simulates the gravitational acceleration of the moon. The flow channel, simulating the flow path of the melt, forms the basis for the cavity structure model. The flow channel is fixedly mounted on the experimental platform, which can rotate the channel to achieve the desired inclination angle. The tilt angle of the flow channel is adjusted to simulate lunar gravitational acceleration using the effective gravity component along the channel's tilt direction. The thermal vacuum chamber needs to be small to medium-sized, modular, and easily reconfigurable to enable rapid experimental iteration. A radiation cooling plate or heat sink is installed inside the thermal vacuum chamber to precisely control the target ambient temperature around the flow channel, avoiding convective heat transfer interference from Earth's atmosphere. The specific value of the tilt angle α is determined based on subsequent similarity criterion verification results, ensuring that the effective gravity component simulating melt flow is approximately 1 / 6 that of the lunar surface. The fluid kinematics are similar under the same environment.

[0053] The experimental platform, integrating precision flow channels, is designed within a thermal vacuum chamber (TVC). The TVC allows for the regulation of internal pressure and temperature to simulate the high vacuum environment and extreme temperatures of the moon. Furthermore, the TVC is equipped with a melt injection / recovery system and a radiative cooling source. The melt injection / recovery system is used to inject and discharge simulated melt into the flow channels, while the radiative cooling source accelerates the cooling and solidification of the simulated melt.

[0054] S3: Similarity Criterion Verification: The goal is to match the dimensionless numbers of Pelet number, dimensional temperature, and Rayleigh number in the actual formation process of the lunar lava tube structure with the Pelet number, dimensional temperature, and Rayleigh number in the physical simulation of the lunar lava tube structure. Based on the physical property parameters of the simulated melt, the inclination angle of the flow channel, the injection rate of the simulated melt, and the target ambient temperature are determined.

[0055] This process uses Pelet number, dimensional temperature, and Rayleigh number constraints to simulate key physical fields such as fluid dynamics, heat conduction, and buoyancy-driven convection during the physical simulation of lunar lava tube structures. This ensures a high degree of similarity between the simulated lunar lava tube structure and its actual formation, overcoming the shortcomings of existing simulation techniques in reproducing the fluid dynamics and heat conduction mechanisms under extreme lunar conditions. Specifically, the Pelet number, dimensional temperature, and Rayleigh number during the actual formation of lunar lava tube structures are first determined based on lunar gravitational acceleration and the actual physical properties of basaltic melt. These physical properties include: density, viscosity (or kinematic viscosity), thermal conductivity, specific heat capacity, thermal diffusivity, coefficient of thermal expansion, and solidification temperature; latent heat and surface emissivity are also included when necessary. To ensure the simulation accurately replicates the actual process, the goal is to match the dimensionless values ​​of the Pelet number, dimensional temperature, and Rayleigh number in the actual formation process of the lunar lava tube structure with those in the physical simulation. Specifically, the Pelet number, dimensional temperature, and Rayleigh number in the actual formation process of the lunar lava tube structure must be equal to those in the physical simulation. This allows for the determination of the channel inclination angle, the injection rate of the simulated melt, and the target ambient temperature based on the Pelet number, dimensional temperature, Rayleigh number, and the physical properties of the simulated melt. The specific calculation process is as follows:

[0056] The function expression for Peclet numbers is:

[0057] ;

[0058] in, Where is the Peckle number, U represents the flow rate of the simulated melt, L represents the characteristic length, and k represents the thermal diffusivity.

[0059] The Peclet number is a functional expression used to describe the ratio of convective heat transfer to thermal diffusion. By matching the Peclet number of the simulated process with that of the actual process, the flow velocity U and injection rate Q of the simulated melt can be constrained, ensuring that the relationship between the formation rate of the crust boundary of the simulated melt and the forward movement rate of the simulated melt is the same as that of the actual formation process of the lunar lava tube structure.

[0060] The functional expression for dimensional temperature is:

[0061] ;

[0062] in, Temperature in a dimension This indicates the initial temperature of the simulated melt. Indicates the target ambient temperature. This indicates the solidification temperature of the simulated melt.

[0063] Dimensional temperature is used to describe the initial temperature of the simulated melt. With the target ambient temperature Relative to the melting point The relative relationship between θ and θ is crucial for controlling the solidification and crust formation on the simulated melt surface. This invention embodiment achieves this by precisely setting... and To match the θ values ​​of the simulated process with those of the actual process, especially to simulate the critical conditions of crust formation under extremely low radiation cooling or high thermal inertia conditions on the moon.

[0064] The functional expression for Rayleigh numbers is:

[0065] ;

[0066] in, For Rayleigh numbers, This represents the Earth's gravitational acceleration. Indicates the coefficient of volume expansion. Indicates characteristic temperature difference, The value can be either the difference between the average temperature of the simulated melt and the target ambient temperature, or the temperature difference between the simulated melt and the outer surface of the crust. Indicates the thickness of the crust. This indicates the viscosity of the simulated melt.

[0067] The Rayleigh number describes the ratio of buoyancy-driven convection to viscous dissipation, influencing the intensity of thermal convection and flow pattern within the simulated melt. This is achieved by adjusting the viscosity of the simulated melt. The effective gravitational acceleration component ensures the dynamic similarity of the simulated internal flow state (laminar / turbulent transition) of the melt.

[0068] The effective gravitational acceleration component depends on the inclination angle of the flow channel; this can be achieved by adjusting the inclination angle of the flow channel. This allows for the alteration of the effective gravitational acceleration component along the inclined direction of the flow channel, thereby simulating the actual flow process of lava under the influence of lunar gravity during the formation of lunar lava tube structures. This ensures that the simulated melt is kinematically similar to that of the lunar surface at 1 / 6 scale. Matching the gravity effect in the environment. The flow channel angle, the injection rate of the simulated melt, and the target ambient temperature can be determined by the Peckle number, dimensional temperature, and Rayleigh number.

[0069] S4: Environmental Coupling System Activation: Adjust the air pressure inside the thermal vacuum chamber to the actual lunar air pressure and adjust the temperature of the flow channel to the target ambient temperature. Specifically, activate the thermal vacuum chamber and reduce the air pressure inside its walls to a high vacuum state to simulate the lunar vacuum state. During the experiment, the air pressure inside the chamber can be controlled to be better than 10. -2 A high vacuum state of Pa. Then, based on the similarity criterion verification results in step S3, the flow channel temperature within the hot vacuum chamber is controlled at the determined target ambient temperature. And adjust the inclination angle of the flow channel to... The angle of the flow channel satisfy:

[0070] ;

[0071] in, This represents the effective gravitational acceleration component along the direction of the channel's inclination. The value is taken as the lunar gravitational acceleration, used to simulate 1 / 6 of the lunar surface. Effective gravitational acceleration under environmental conditions.

[0072] S5: Controlled Flow and Crust Formation: Simulated melt is injected into the flow channel according to the injection rate, and the crust thickness of the simulated melt within the channel is monitored. Specifically, the simulated melt is first heated to an initial temperature that meets the dimensional temperature requirements. To ensure uniformity of the thermal boundary conditions between the simulated melt and the flow channel surface, a layer of solidified paraffin substrate needs to be pre-placed at the bottom of the flow channel. Then, the simulated melt is injected into the flow channel at an injection rate that satisfies the Peckley number similarity constraint. The flow velocity of the simulated melt within the flow channel is monitored in real time, and feedback is provided to ensure that the simulated melt operates under the set flow conditions, accurately simulating the dynamic processes under high volumetric flow rates on the moon. The crust thickness of the simulated melt within the flow channel is also monitored.

[0073] S6: Surface Shell Solidification and Melt Evacuation: In a vacuum environment, the solidification of the simulated melt is accelerated primarily through radiative cooling. Due to the target ambient temperature... Used to simulate the extreme temperatures of the moon, so in At the specified temperature, a robust outer shell can be induced to form rapidly on the outer surface of the simulated melt. To complete the shell formation within an operable experimental time and achieve time-scaling similarity, once the simulated melt surface begins to form a shell, a controlled cooling medium (e.g., deionized water mist) can be uniformly sprayed to accelerate the formation of the localized shell.

[0074] When the real-time crust thickness reaches the preset critical thickness, the simulated melt injection is terminated. To ensure the internal melt is emptied without causing unexpected collapse of the crust under experimental conditions, the leading edge of the solidified simulated melt needs to be manually cut open. This opens the solidified simulated melt within the flow channel, allowing the remaining undone simulated melt to drain. This step releases the high-temperature simulated melt accumulated inside, allowing it to drain rapidly under effective gravitational acceleration, leaving a structurally intact cavity. This enables researchers to focus on the physical process of crust formation itself. After the undone simulated melt is drained, the solidified simulated melt within the flow channel forms a cavity structure model.

[0075] In addition, other drainage methods can be used to drain the unsolidified simulated melt in the flow channel.

[0076] S7: Geometric Parameter Extraction: A high-resolution 3D scanning device is used to perform a 3D scan of the cavity structure model, and a lunar lava tube structure model is constructed based on the scan parameters. Specifically, after obtaining the cavity structure model, a high-resolution 3D scanning device is used to perform a 3D scan of the solidified cavity structure model to extract the geometric parameters of the cavity structure model. The geometric parameters to be extracted include: the maximum width, maximum height, average thickness of the crust tube, and the fine morphology of the cross-section. The extracted geometric parameters are used for 3D virtual reconstruction to construct the lunar lava tube structure model. This model serves as quantitative input data for subsequent verification of the lava tube formation mechanism theoretical model and engineering stability analysis.

[0077] The extraction of geometric structural parameters employs high-precision industrial CT scanning or 3D laser scanning technology, achieving an overall reconstruction accuracy of better than 1 cm for the lunar lava tube structure model.

[0078] Based on the cross-scale study of similarity theory, this invention accurately simulates the dynamic process of the formation of lunar lava tube structures through the coupling of multiple physical fields of heat, fluid and force. It also jointly controls the low gravity, high vacuum, high volumetric flow rate and pure radiation cooling of the simulated melt, so as to reconstruct the physical conditions for the formation of lunar lava tube structures in a laboratory environment and ensure that the actual formation process of lunar lava tube structures and the simulation process in the laboratory meet the strict dimensionless similarity criteria.

[0079] In summary, the above description is merely a preferred embodiment of this specification and is not intended to limit the scope of protection of this specification. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this specification should be included within the scope of protection of this specification.

[0080] The systems, apparatuses, modules, or units described in one or more of the above embodiments may be implemented by a computer chip or entity, or by a product having a certain function. A typical implementation device is a computer. Specifically, a computer may be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smartphone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or any combination of these devices.

[0081] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0082] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

Claims

1. A physical simulation method for the formation process of lunar lava tube structures, characterized in that, include: S1: Prepare a simulated melt by mixing thermoplastic materials with condensation additives; S2: The flow channel is placed in a hot vacuum cavity, wherein the tilt angle of the flow channel is adjustable, and the tilt angle of the flow channel is designed to simulate the gravitational acceleration of the moon. S3: With the goal of matching the dimensionless numbers of Peckled number, dimensional temperature, and Rayleigh number in the actual formation process of the lunar lava tube structure with the Peckled number, dimensional temperature, and Rayleigh number in the physical simulation of the lunar lava tube structure, the inclination angle of the flow channel, the injection rate of the simulated melt, and the target ambient temperature are determined by inversion based on the physical property parameters of the simulated melt. S4: Adjust the air pressure inside the thermal vacuum cavity to the actual air pressure on the moon, and adjust the temperature of the flow channel to the target ambient temperature; S5: Inject the simulated melt into the flow channel according to the injection rate of the flow channel, and monitor the shell thickness of the simulated melt in the flow channel; S6: When the thickness of the shell reaches the preset critical thickness, the injection of the simulated melt is terminated, and the simulated melt remaining in the flow channel is emptied to obtain a cavity structure model. S7: Use a high-resolution 3D scanning device to perform a 3D scan on the cavity structure model, and construct a lunar lava tube structure model based on the scanning parameters.

2. The physical simulation method for the formation process of lunar lava tube structures according to claim 1, characterized in that, The thermoplastic material is paraffin wax, and the condensation additive is 1500-mesh talc powder.

3. The physical simulation method for the formation process of lunar lava tube structures according to claim 2, characterized in that, The mixing ratio of 1500 mesh talc is 10% to 25%.

4. The physical simulation method for the formation process of lunar lava tube structures according to claim 1, characterized in that, The goal is to match the dimensionless values ​​of the Pelet number, dimensional temperature, and Rayleigh number in the actual formation process of lunar lava tube structures with those in the physical simulation of lunar lava tube structures. This includes setting the Pelet number, dimensional temperature, and Rayleigh number in the physical simulation of lunar lava tube structures to be equal to those in the actual formation process of lunar lava tube structures.

5. The physical simulation method for the formation process of lunar lava tube structures according to claim 1, characterized in that, The function expression for Peclet numbers is: ； in, Where is the Peckle number, U represents the flow velocity of the simulated melt, L represents the characteristic length, and k represents the thermal diffusivity; The functional expression for dimensional temperature is: ； in, Temperature in a dimension This indicates the initial temperature of the simulated melt. Indicates the target ambient temperature. Indicates the solidification temperature of the simulated melt; The functional expression for Rayleigh numbers is: ； in, For Rayleigh numbers, This represents the Earth's gravitational acceleration. Indicates the coefficient of volume expansion. Indicates characteristic temperature difference, Indicates the thickness of the crust. This indicates the viscosity of the simulated melt.

6. The physical simulation method for the formation process of lunar lava tube structures according to claim 1, characterized in that, The inclination angle of the flow channel satisfy: ； in, This represents the effective gravitational acceleration component along the inclined direction of the flow channel. The value is taken as the lunar gravitational acceleration.

7. The physical simulation method for the formation process of lunar lava tube structures according to claim 5, characterized in that, The Peclet number is used to control the relationship between the formation rate of the crust boundary of the simulated melt and the forward movement speed of the simulated melt, which is the same as the actual formation process of the lunar lava tube structure. The dimensional temperature is used to control the critical conditions for crust formation of the simulated melt, which is the same as the actual formation process of lunar lava tube structures. The Rayleigh number is used to control the flow state of the simulated melt, which is the same as the actual formation process of the lunar lava tube structure.

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