TPMS self-suction phase change sweating cooling porous structure and construction method thereof

Abstract

The invention provides a TPMS self-suction phase change sweating cooling porous structure and a construction method thereof. Comprising a liquid phase conveying area used for initial entering and stable conveying of cooling liquid, a capillary liquid supply area used for continuously conveying the cooling liquid to the position close to the high-temperature environment side through the capillary action under the condition of no additional pump and a phase change evaporation area used for phase change evaporation and heat exchange of the cooling liquid, and the liquid phase conveying area, the capillary liquid supply area and the phase change evaporation area are sequentially arranged in a stacked mode in the thickness direction. A gas phase outlet area used for discharging steam generated by phase change in a directional and low-resistance manner is embedded in a local area, close to the high-temperature environment side, in the phase change evaporation area; the invention has the following beneficial effects: continuous fusion of different TPMS structures is realized in the porous layer along the thickness direction, and a gas phase outlet structure based on TPMS topological characteristics is arranged on the high-temperature side, so that stable self-suction transportation of a cooling liquid and directional and efficient discharge of a gas phase are realized; therefore, the heat transfer efficiency, the operation stability and the structural integrity of phase change sweating cooling are improved.

Description

Technical Field

[0001] This invention relates to the field of porous structure technology, and in particular to a TPMS self-absorption phase change sweating cooling porous structure and its construction method. Background Technology

[0002] 1. Introduction to phase change sweating cooling technology:

[0003] With the continuous development of hypersonic vehicles, high-temperature gas components, and high heat flux density thermal protection systems, the heat flux density experienced by walls in service environments is constantly increasing. Traditional passive cooling methods that rely on radiation, conduction, or convection heat transfer are no longer sufficient to provide reliable and continuous thermal protection under extreme conditions. To meet the demands of these harsh thermal environments, there is an urgent need to develop new active cooling technologies with high cooling efficiency and sustainable operation capabilities.

[0004] Transpiration cooling with phase change (TCO) is a highly efficient active cooling technology that introduces liquid coolant into a porous structure beneath a high-temperature wall surface. During heating, the coolant vaporizes and absorbs heat, significantly reducing the wall temperature. It has attracted widespread attention due to its high cooling efficiency and low coolant consumption. In TCO cooling, the porous medium not only acts as a coolant transport channel but also directly participates in the liquid-vapor phase change process. Its structural characteristics (such as porosity, pore size distribution, connectivity, and surface wettability) have a decisive influence on the coolant supply capacity, evaporation location distribution, and vapor discharge path. Therefore, the rational design of the porous medium structure is crucial for achieving efficient and stable TCO cooling.

[0005] 2. Self-extraction phase change sweating cooling and its special requirements for porous structures:

[0006] To further reduce system complexity and improve reliability in engineering applications, a type of self-extraction phase change evaporation cooling technology has been proposed in recent years. This technology does not rely on external pumping devices; instead, it utilizes the capillary pressure generated within the porous medium and the pressure difference induced by the evaporation process to achieve spontaneous transport of the coolant from the low-temperature side to the high-temperature side. Compared with traditional forced-supply evaporation cooling, self-extraction phase change evaporation cooling offers significant advantages such as compact structure, low energy consumption, and simplified control system, making it particularly suitable for thermal protection scenarios with high reliability requirements.

[0007] However, under self-suction conditions, the coolant supply capacity relies entirely on the capillary driving force and phase change-induced effect of the porous medium itself. This places more stringent and contradictory requirements on the porous medium structure. On the one hand, in the low-temperature region near the coolant inlet, the porous medium needs to have sufficiently high capillary pressure to overcome gravity, flow resistance, and evaporation losses, ensuring that the coolant can be continuously and stably transported to the high-temperature region. On the other hand, in the region near the high-temperature wall, the coolant undergoes violent vaporization and generates a large amount of steam. If the steam cannot be discharged in time, it is very easy to form steam retention or even steam blockage inside the porous medium, thereby significantly inhibiting liquid replenishment, leading to local drying and reducing overall cooling performance. Therefore, self-suction phase change sweating cooling places a structural requirement on the porous medium to have both "strong capillary liquid supply" and "low-resistance steam discharge." These two requirements are often mutually restrictive at the level of porous structure parameters and are difficult to meet simultaneously through simple structural design.

[0008] 3. Current technological status of porous media structure design:

[0009] 1) Limitations of uniform porous structures: Currently, commonly used porous media in phase change sweating cooling systems include sintered metals, porous ceramics, metal foams, and randomly porous materials. These porous media typically have approximately uniform porosity and pore size distribution, mature manufacturing processes, and stable structures, and have been applied in various thermal management scenarios.

[0010] However, under self-suction phase change evaporation cooling conditions, uniform porous structures struggle to simultaneously meet the dual requirements of liquid transport and vapor discharge: smaller pore sizes, while beneficial for increasing capillary pressure, significantly increase gas flow resistance; while larger pore sizes, though beneficial for vapor discharge, noticeably weaken capillary driving force, leading to insufficient liquid supply capacity. Therefore, uniform porous media employing a single structural parameter generally suffer from performance bottlenecks under complex phase change conditions.

[0011] 2) Introduction of Single-Type TPMS Porous Structures: In recent years, Triply Periodic Minimal Surface (TPMS) structures have been introduced into porous media design due to their continuous and smooth surface morphology, good isotropic interconnected channels, and high specific surface area, to enhance flow, heat transfer, and phase change processes. Common TPMS structures include Primitive, Gyroid, and Diamond types.

[0012] In existing technologies, a single type of TPMS structure is typically used to construct the entire porous layer, and porosity and characteristic dimensions are altered by adjusting implicit function parameters or scaling the overall dimensions. Compared to traditional random porous materials, a single TPMS structure offers significant advantages in terms of geometric controllability and repeatability. However, different types of TPMS structures exhibit significant differences in capillary force, permeability, and interfacial curvature distribution. A single type of TPMS structure within the same porous layer still struggles to simultaneously meet multiple functional requirements such as liquid supply, evaporation, and vapor exhaust, thus its structural function remains distinctly singular.

[0013] 3) Existing attempts at layered or composite porous structures: To overcome the shortcomings of homogeneous structures, some existing technologies propose introducing layered or composite structures within the porous layer. For example, using porous media with different porosities or materials in different thickness regions to balance the liquid supply and steam exhaust requirements to some extent. However, such solutions typically employ a simple layering method, where the porosity, pore size, and connectivity between different porous structures abruptly change at the interlayer interface. This can easily cause discontinuities in capillary pressure and permeability, leading to instability at the liquid-vapor interface between layers, and even inducing problems such as localized drying or liquid accumulation, thereby affecting the stability and reliability of the system operation.

[0014] 4) Current technological status of gas phase transport and gas phase outlet design: In the phase change sweating cooling process, the coolant vaporizes inside the porous medium near the high-temperature wall. The generated vapor needs to be discharged from the porous structure in a timely manner to maintain the unobstructed flow of the liquid phase transport channel and ensure the continuous stability of the phase change process. Therefore, the gas phase transport capacity and the reasonable design of the gas phase outlet are important factors affecting the performance and reliability of phase change sweating cooling.

[0015] In existing technologies, steam exhaust typically relies on the interconnected channels of the porous medium itself, or indirectly reduces gas flow resistance by increasing the overall porosity and pore size. The gas and liquid phases often share the same pore network. However, under self-extraction phase change evaporation cooling conditions, these passive exhaust methods easily lead to channel competition between steam and liquid within the porous medium, resulting in significant steam retention. Enlarging the overall pore structure to enhance exhaust capacity significantly weakens capillary driving force, hindering continuous spontaneous replenishment of the coolant. Furthermore, some existing solutions achieve exhaust through wall openings or additional gas channels, but these structures typically disrupt the continuity of the porous medium's framework and lack coordinated design with the internal structure of the porous medium.

[0016] 4. The closest existing technology and its shortcomings:

[0017] 4.1 Technology 1: Using a Triple Periodic Minimal Surface Structure to Construct a Porous Thermal Protection Layer for Phase Change Sweating Cooling: 1) Technology Introduction: In phase change sweating cooling systems, a porous layer is constructed using a single type of triple periodic minimal surface porous structure, and its transport and heat transfer performance is adjusted by adjusting the overall porosity or characteristic dimensions. In recent years, the triple periodic minimal surface (TPMS) structure has been introduced into porous media design due to its continuous surface, high specific surface area, and good structural connectivity, to enhance flow and heat transfer performance. In existing technologies, a single type of TPMS structure (such as P-type, G-type, or D-type) is often used to construct the entire porous layer, or its porosity is adjusted by scaling the overall dimensions.

[0018] 2) Technical Deficiencies: Although a single TPMS structure has certain advantages in geometric controllability compared to traditional random porous media, it still has the following shortcomings under self-extraction phase change sweating cooling conditions: a) Single structural function: A single TPMS structure cannot simultaneously achieve high capillary driving force, high permeability, and high evaporation efficiency within the same porous layer, and there are still obvious conflicts between the various functional requirements. b) Lack of dedicated structure for gas phase discharge: In existing technologies, steam still mainly relies on random escape through the internal channels of the porous medium, lacking a clear gas phase discharge path design, which easily leads to steam retention near high-temperature regions. c) Limited porosity control methods: Existing technologies usually adjust porosity by scaling the overall scale, making it difficult to achieve continuous gradient changes in the thickness direction, and unable to accurately match the functional requirements of different regions during self-extraction phase change sweating cooling.

[0019] 4.2 Technology 2: Phase Change Sweating Cooling Porous Thermal Protection Layer with Gradient Porosity Layout of Single Structure: 1) Technology Introduction: In phase change sweating cooling or enhanced heat transfer applications, a single-morphology porous structure (including a single type of TPMS structure) is used, and the structural scale or geometric parameters are gradually changed along the thickness direction to form a porous medium layout with a gradient distribution of porosity or equivalent pore size. This type of technology usually achieves different porosities at different thickness locations by scaling the same geometric unit or adjusting implicit function parameters, in order to balance flow resistance and heat transfer performance to a certain extent.

[0020] 2) Technical shortcomings: While the single-morphology porous media with the aforementioned gradient layout improves the overall performance of the porous layer to some extent compared to a completely homogeneous structure, it still has the following shortcomings under self-absorption phase change sweating cooling conditions:

[0021] a. Limited functional control due to the homogeneous structural topology: Although porosity varies along the thickness direction, the topological type of the porous medium remains unchanged. Its connectivity, curvature distribution, and pore morphology are highly similar in different regions, making it difficult to perform functional design for different physical processes (liquid transport, capillary supply, phase change evaporation, gas phase escape). Essentially, it still belongs to the category of "parameter gradient" rather than "structural gradient".

[0022] b. The coupling relationship between capillary force and permeability is difficult to decouple: Under a single structural topology, capillary pressure and permeability usually exhibit a strong coupling relationship with changes in porosity: although increasing porosity can reduce flow resistance, it also significantly weakens capillary driving force. Therefore, gradient porosity can only be optimized within a certain range and it is still difficult to achieve targeted requirements such as "strong capillary + high permeability" or "low capillary + high exhaust" in local areas.

[0023] c. The regulation of gas phase transport remains passive: Gradient single-structure porous media still mainly affect the steam discharge capacity indirectly through changes in porosity, without providing a dedicated, low-resistance discharge channel for the gas phase at the structural level. Steam still competes with liquid for channel resources inside the porous media, and the steam blockage problem is still difficult to avoid fundamentally.

[0024] d. Difficulty in achieving functional zoning and synergistic optimization within porous layers: Existing gradient single-structure schemes usually aim to improve overall performance, but lack clear structural division of liquid supply zone, phase change zone and exhaust zone, making it difficult to achieve synergistic work and overall optimization between different regions within the porous layer.

[0025] In summary, existing phase change sweating cooling porous media design schemes, whether uniform structures, single TPMS structures, or gradient pore layouts based on a single topology, have not broken through the functional coupling limitations caused by the single topology of porous structures. Moreover, they generally lack structural designs for directional gas phase discharge, making it difficult to meet the differentiated and synergistic functional requirements of self-extraction phase change sweating cooling for porous media in different thickness regions. Summary of the Invention

[0026] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a TPMS self-extraction phase change sweating cooling porous structure and its construction method, in order to solve the problem that the prior art has not yet broken through the functional coupling limitation caused by the single structural topology, and lacks structural design for directional gas phase discharge, making it difficult to meet the differentiated functional requirements of the porous medium in different thickness regions for self-extraction phase change sweating cooling.

[0027] To achieve the above and other related objectives, the present invention provides the following technical solution:

[0028] A TPMS self-suction phase change sweating cooling porous structure includes a liquid phase transport zone for initial entry and stable transport of coolant, a capillary supply zone for continuously transporting coolant to the side near the high-temperature environment via capillary action without an external pump, and a phase change evaporation zone for phase change evaporation and heat exchange of coolant, arranged sequentially along the thickness direction. The side of the liquid phase transport zone away from the capillary supply zone is closer to the coolant supply side, and the side of the phase change evaporation zone away from the capillary supply zone is closer to the high-temperature environment side. A local area in the phase change evaporation zone near the high-temperature environment side is embedded with a gas phase outlet zone for directional and low-resistance discharge of vapor generated by phase change. The gas phase outlet zone can penetrate the phase change evaporation zone in the thickness direction, and the gas phase outlet zone is discretely distributed or arrayed in the planar direction.

[0029] In one embodiment of the present invention, the liquid phase transport zone adopts a P-type three-period minimal surface structure configuration, the capillary liquid supply zone adopts a G-type three-period minimal surface structure configuration, the phase change evaporation zone adopts a D-type three-period minimal surface structure configuration, and the gas phase outlet zone adopts a P-type or I-WP-type three-period minimal surface structure configuration.

[0030] In one embodiment of the present invention, the implicit function expression of the P-type three-period minimal surface structure configuration is: cos(2πx)+cos(2πy)+cos(2πz)=0; the implicit function expression of the G-type three-period minimal surface structure configuration is: sin(2πx)cos(2πy)+sin(2πy)cos(2πz)+sin(2πz)cos(2πx)=0;

[0031] The implicit function expression for the D-type three-period minimal surface structure configuration is: sin(2πx)sin(2πy)sin(2πz)+sin(2πx)cos(2πy)cos(2πz)+cos(2πx)sin(2πy)cos(2πz)+cos(2πx)cos(2πy)sin(2πz)=0; the implicit function expression for the I-WP type three-period minimal surface structure configuration is: 2[cos(2πx)cos(2πy)+cos(2πy)cos(2πz)+cos(2πz)cos(2πx)]-[cos(4πx)+cos(4πy)+cos(4πz)]=0; where, , , The three-dimensional spatial coordinate variables are used to construct the three-period minimal surface structure, which correspond to the spatial position parameters of the porous structure in three mutually orthogonal directions.

[0032] In one embodiment of the present invention, a PG longitudinal fusion unit is provided between the liquid phase transport zone and the capillary liquid supply zone, and a GD longitudinal fusion unit is provided between the capillary liquid supply zone and the phase change evaporation zone.

[0033] In the PG longitudinal fusion unit, the P-type three-period minimal surface structure configuration and the G-type three-period minimal surface structure configuration are smoothly fused in the longitudinal direction. In the GD longitudinal fusion unit, the G-type three-period minimal surface structure configuration and the D-type three-period minimal surface structure configuration are smoothly fused in the longitudinal direction.

[0034] In one embodiment of the present invention, both the PG longitudinal fusion unit and the GD longitudinal fusion unit achieve a smooth transition between different TPMS structural regions by using a longitudinal sigmoid function to regulate the continuous change of the TPMS implicit function. The longitudinal sigmoid function changes smoothly within the range of 0 to 1, ensuring that the structure has no geometrical abrupt changes and maintaining the continuous liquid transport capability. Its functional expression is as follows: ;

[0035] in, For vertical sigmoid function; For spatial independent variables, it represents the spatial variables that participate in transition modulation; It is the transition center position, representing the center of symmetry of the longitudinal sigmoid function; It is a transition steepness control parameter used to control the steepness of the longitudinal sigmoid curve.

[0036] In one embodiment of the present invention, a circumferential fusion unit is provided between the phase change evaporation zone and the gas phase outlet zone; in the circumferential fusion unit, the D-type three-period minimal surface structure configuration and the P-type or I-WP-type three-period minimal surface structure configuration are smoothly fused in the circumferential direction by a distance-based sigmoid function.

[0037] In one embodiment of the present invention, the distance-based sigmoid function can continuously modulate the TPMS function parameters according to the distance from each point to the center or boundary to achieve a smooth circumferential geometric transition. The expression of the distance-based sigmoid function is as follows:

[0038] ;in, This is a distance-based sgmoid function; It is represented as the spatial distance from any point to the center of the target structure; The coordinates are the center of the target structure, that is, the center coordinates of the gas phase outlet region or local functional structure; The transition radius represents the characteristic distance from which the transition of the sgmoid function occurs.

[0039] A method for constructing a TPMS self-extraction phase change sweating cooling porous structure, based on the aforementioned TPMS self-extraction phase change sweating cooling porous structure, includes the following steps: the porous structure is constructed based on a unified TPMS implicit function system, and geometric continuity and topological consistency are achieved among P-type three-period minimal surface structure configurations, G-type three-period minimal surface structure configurations, D-type three-period minimal surface structure configurations, and P-type or I-WP type three-period minimal surface structure configurations through continuous function modulation;

[0040] By setting the TPMS parameters of each functional area, the porous layer as a whole forms a gradient distribution with gradually decreasing porosity along the thickness direction. The liquid phase transport zone has the highest porosity, the phase change evaporation zone has the lowest porosity, the capillary liquid supply zone has a porosity between that of the liquid phase transport zone and the phase change evaporation zone, and the gas phase outlet zone has a higher porosity than that of the phase change evaporation zone.

[0041] In one embodiment of the present invention, the TPMS parameters along the thickness direction are controlled by the smoothstep function to achieve a continuous gradient of porosity from high to low in the porous layer. The expression of the smoothstep function is as follows:

[0042] ;in, It is a dimensionless parameter used to describe the relative position of a structure or porosity along a spatial direction.

[0043] As described above, the TPMS self-suction phase change sweating cooling porous structure and its construction method of the present invention have the following beneficial effects: The present invention constructs a gradient porous medium with clear functional partitions and smooth transition of structural parameters by continuously fusing TPMS structures of different topological types along the thickness direction in the same porous layer, and sets an embedded gas phase outlet structure formed by a high-permeability TPMS configuration on the high-temperature side, so that the gas phase discharge path is continuously unified with the porous structure topology, thereby realizing stable self-suction transport of coolant and directional, efficient and low-disturbance discharge of gas phase, further improving the heat transfer efficiency, structural stability and long-term operational reliability of the phase change sweating cooling process. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the overall structure of the TPMS self-absorption phase change sweating cooling porous structure disclosed in the embodiments of the present invention;

[0045] Figure 2 This is a schematic diagram of the P-type TPMS structural unit in the TPMS self-absorption phase change sweating cooling porous structure disclosed in the embodiments of the present invention;

[0046] Figure 3This is a schematic diagram of the liquid transport zone composed of P-type units in the TPMS self-suction phase change sweating cooling porous structure disclosed in this embodiment of the invention.

[0047] Figure 4 This is a schematic diagram of the G-type TPMS structural unit in the TPMS self-absorption phase change sweating cooling porous structure disclosed in the embodiments of the present invention;

[0048] Figure 5 This is a schematic diagram of the capillary liquid supply area composed of G-type units in the TPMS self-suction phase change sweating cooling porous structure disclosed in this embodiment of the invention.

[0049] Figure 6 This is a schematic diagram of the D-type TPMS structural unit in the TPMS self-extraction phase change sweating cooling porous structure disclosed in the embodiments of the present invention;

[0050] Figure 7 This is a schematic diagram of the phase change evaporation zone composed of D-type units in the TPMS self-suction phase change sweating cooling porous structure disclosed in this embodiment of the invention;

[0051] Figure 8 This is a structural diagram of the phase change evaporation zone embedded with the gas phase outlet zone in the TPMS self-suction phase change sweating cooling porous structure disclosed in this embodiment of the invention.

[0052] Figure 9 This is a schematic diagram of the PG fusion unit in the TPMS self-extraction phase change sweating cooling porous structure disclosed in this embodiment of the invention;

[0053] Figure 10 This is a schematic diagram of the GD fusion unit in the TPMS self-extraction phase change sweating cooling porous structure disclosed in this embodiment of the invention;

[0054] Figure 11 This is a schematic diagram of the DP circumferential fusion unit (P-type in the upper right corner) in the TPMS self-suction phase change sweating cooling porous structure disclosed in this embodiment of the invention.

[0055] Figure 12 This is a schematic diagram of the D-IWP circumferential fusion unit (IWP type in the upper right corner) in the TPMS self-suction phase change sweating cooling porous structure disclosed in this embodiment of the invention;

[0056] Figure 13 This is a schematic diagram showing the geometric changes in the TPMS unit structure as the porosity gradually decreases along the thickness direction in the liquid phase transport region of the TPMS self-suction phase change sweating cooling porous structure disclosed in this embodiment of the invention.

[0057] Component designation explanation

[0058] 1. Liquid phase transport zone; 2. Capillary liquid supply zone; 3. Phase change evaporation zone; 301. Gas phase outlet zone. Detailed Implementation

[0059] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. It should be noted that, unless otherwise specified, the following embodiments and features described herein can be combined with each other.

[0060] Please see Figure 1 This invention relates to a TPMS self-extraction phase change sweating cooling porous structure and its construction method. Specifically, it is a TPMS self-extraction phase change sweating cooling porous structure based on structural fusion and gradient porosity. The structure is set between the high-temperature environment side and the coolant supply side, and is used for coolant self-extraction and transport, phase change evaporation and gas phase discharge when the component is directly exposed to high-temperature heat flow conditions.

[0061] The porous structure includes a liquid phase transport region 1, a capillary liquid supply region 2, and a phase change evaporation region 3, which are stacked sequentially along the thickness direction. The side of the liquid phase transport region 1 away from the capillary liquid supply region 2 is close to the coolant supply side, and the side of the phase change evaporation region 3 away from the capillary liquid supply region 2 is close to the high-temperature environment side. Among them, a gas phase outlet region 301 based on TPMS topology is embedded in a local area of ​​the phase change evaporation region 3 near the high-temperature environment side for directional and low-resistance discharge of vapor generated by phase change.

[0062] It should be noted that the liquid transport zone 1 adopts a P-type three-period minimal surface (TPMS) structure, which has strong channel connectivity and high equivalent permeability, and is used to reduce liquid flow resistance and improve the bottom-up transport capacity of coolant.

[0063] The capillary supply zone 2 adopts a G-type TPMS structure configuration, which has high curvature distribution uniformity and capillary driving force, which is conducive to maintaining a stable self-suction supply of coolant to the high-temperature side without the need for an external pump.

[0064] The phase change evaporation zone 3 adopts a D-type TPMS structure configuration, which has a large specific surface area and complex interface morphology, which can significantly enhance the phase change evaporation intensity of the liquid-vapor interface and improve the phase change heat transfer efficiency per unit volume.

[0065] In the phase change evaporation zone 3, a gas phase outlet zone 301 is embedded in a local area near the high temperature side. The gas phase outlet zone 301 adopts a P-type or I-WP type TPMS structure configuration, and by locally modulating the implicit function parameters of the TPMS, the permeability of this area is higher than the average level of the phase change evaporation zone, thus forming a low-resistance channel for preferential steam discharge.

[0066] The porous structure is constructed based on a unified TPMS implicit function system. Through continuous function modulation, it achieves geometric continuity and topological consistency between P-type, G-type, D-type and gas phase outlet configurations (P-type or I-WP type), avoiding the flow and phase change instability problems caused by structural abrupt changes in traditional layered porous media. At the same time, by setting the TPMS parameters of each functional area, the porous layer forms a gradient distribution with gradually decreasing porosity along the thickness direction. Among them, the porosity of liquid phase transport zone 1 is the highest, followed by capillary liquid supply zone 2, and phase change evaporation zone 3 has the lowest porosity. The porosity of gas phase outlet zone 301 is higher than that of phase change evaporation zone 3, so as to balance the requirements of self-pumping directional liquid supply capability and efficient steam discharge.

[0067] Specifically, liquid phase transport region 1: The porous layer of this invention has a liquid phase transport region 1 near the coolant supply side. This region is mainly used for the initial entry and stable transport of coolant. The liquid phase transport region 1 adopts a P-type three-period minimal surface (TPMS) structure configuration; its implicit structural function expression is: cos(2πx)+cos(2πy)+cos(2πz)=0, and the P-type unit is as follows: Figure 2 As shown, the P-type TPMS has topological characteristics of strong channel connectivity and low channel tortuosity, making it suitable for realizing the overall transport of liquids under low driving force conditions.

[0068] like Figure 3 As shown, the thickness of the liquid transport region 1 accounts for approximately 30%-40% of the total thickness of the porous layer. For example, in a porous layer with a total thickness of 300 mm, the thickness of this region can be set to 90-120 mm, and the porosity of this region is set to a relatively high level, such as 0.60-0.75. Under evaporative cooling conditions, this region provides a low-flow-resistance entry path for the coolant through its high porosity and highly interconnected pore structure. At the same time, this region serves as the "source end" of the entire evaporation gradient structure, providing stable liquid replenishment conditions for subsequent regions with gradually decreasing porosity.

[0069] Capillary supply area 2: such as Figure 4 As shown, the porous layer of this invention has a capillary supply zone 2 above the liquid phase transport zone. This zone is mainly used to continuously transport coolant to the side near the high-temperature environment through capillary action without an external pump. The capillary supply zone adopts a G-type three-period minimal surface (TPMS) structure configuration, and its implicit structural function expression is: sin(2πx)cos(2πy)+sin(2πy)cos(2πz)+sin(2πz)cos(2πx)=0; the G-type TPMS unit is as follows: Figure 4 As shown, G-type TPMS has a relatively uniform pore distribution and a small characteristic radius of curvature. Under wetting conditions, it can generate a large capillary pressure at the solid-liquid interface, making it suitable for constructing a stable capillary liquid supply structure.

[0070] like Figure 5 As shown, the thickness of the capillary liquid supply zone 2 accounts for approximately 30%-40% of the total thickness of the porous layer. For example, in a porous layer with a total thickness of 300 mm, the thickness of this zone can be set to 90-120 mm. The porosity of this zone is lower than that of the liquid phase transport zone, for example, set to 0.45-0.60. During the sweating cooling process, due to the reduced porosity and smaller pore size in this zone, the coolant is subjected to stronger capillary adsorption in this zone. Thus, under the combined effect of the porosity gradient, it spontaneously migrates from the liquid phase transport zone to the high-temperature side, realizing an automatic liquid supply process similar to plant transpiration.

[0071] Phase change evaporation zone 3: In this invention, a phase change evaporation zone 3 is set in the porous layer near the high-temperature environment. This zone is mainly used for phase change evaporation and heat exchange of the coolant. The phase change evaporation zone 3 adopts a D-type three-period minimal surface (TPMS) structure configuration, and its implicit function expression is: sin(2πx)sin(2πy)sin(2πz)+sin(2πx)cos(2πy)cos(2πz)+cos(2πx)sin(2πy)cos(2πz)+cos(2πx)cos(2πy)sin(2πz)=0; D-type TPMS unit as follows Figure 6 As shown, D-type TPMS has a complex pore wall morphology and a large specific surface area, which is conducive to the formation and expansion of the liquid-vapor interface, thereby enhancing the phase change evaporation process;

[0072] like Figure 7 As shown, the thickness of the phase change evaporation zone 3 accounts for approximately 20%-30% of the total thickness of the porous layer. For example, in a porous layer with a total thickness of 300 mm, the thickness of this zone can be set to 60-90 mm. The porosity of this zone is further reduced, for example, to 0.30-0.45. Under the action of high-temperature heat flow, the coolant undergoes rapid phase change evaporation in this zone, absorbing a large amount of latent heat to reduce the structural temperature. At the same time, since this zone has the lowest porosity and the strongest capillary adsorption capacity, it can continuously obtain coolant replenishment from the capillary supply zone during the evaporation process, avoiding the occurrence of local drying.

[0073] Embedded gas phase outlet region 301: such as Figure 8As shown, the present invention embeds a gas phase outlet region 301 within the phase change evaporation zone 3, in a local area near the high-temperature environment, for the discharge of steam generated by the phase change. This gas phase outlet region 301 adopts a P-type or I-WP-type three-period minimal surface (TPMS) structure configuration. By locally modulating the implicit function of the TPMS, a locally high-permeability channel is formed without disrupting the overall structural continuity. The implicit function expression of the I-WP-type three-period minimal surface structure configuration is: 2[cos(2πx)cos(2πy)+cos(2πy)cos(2πz)+cos(2πz)cos(2πx)]-[cos(4πx)+cos(4πy)+cos(4πz)]=0, where the implicit function... , , The three-dimensional spatial coordinate variables used to construct the three-period minimal surface structure correspond to the spatial position parameters of the porous structure in three mutually orthogonal directions. Their values ​​can be dimensionless coordinates or scale-normalized spatial coordinates. Furthermore, in the implicit function expression above, the 2π coefficient is used to introduce spatial periodicity, ensuring that the constructed three-period minimal surface structure... , , It exhibits periodic repetition in all three directions;

[0074] The gas phase outlet region 301 can penetrate the phase change evaporation region in the thickness direction and is discretely or arrayed in the planar direction. Although the overall porosity of the porous layer gradually decreases along the thickness direction, the gas phase outlet region is set to have a higher equivalent porosity than the surrounding D-type evaporation structure in its local area, for example, 0.6-0.65, thereby providing a low-resistance discharge path for the steam. During the sweating and cooling process, the steam preferentially accumulates and is discharged in the gas phase outlet region, effectively reducing the risk of steam retention and blockage inside the porous layer, thereby maintaining the long-term stability of the continuous liquid phase supply and evaporation-driven process.

[0075] More specifically, the vertical fusion unit: the present invention provides a PG vertical fusion unit between the liquid phase transport zone 1 and the capillary liquid supply zone 2, and a GD vertical fusion unit between the capillary liquid supply zone 2 and the phase change evaporation zone 3;

[0076] like Figure 9 In the PG vertical fusion unit, P-type accounts for 55%-60% of the bottom and G-type accounts for 40%-45% of the upper part. There is also a gradient change in porosity along the thickness direction, with P-type approximately 0.60-0.75 and G-type approximately 0.45-0.60. P-type provides high-permeability channels, while G-type provides capillary driving force. The two are smoothly fused vertically, achieving continuity and stability of spontaneous coolant transport. Figure 10In the GD vertical fusion unit, the G type occupies 55%-60% of the bottom and the D type occupies 40%-45% of the top. Through continuous TPMS function modulation, the continuity of the capillary force gradient and the liquid channel connectivity is ensured, the liquid film spreading ability of the evaporation zone is enhanced, and the instability of liquid transport is avoided.

[0077] The above vertical fusion unit achieves a smooth transition between different TPMS structural regions by using the vertical sigmoid function to regulate the continuous change of the TPMS implicit function. Its function expression is as follows: ;in, For vertical sigmoid function; The spatial independent variable (transition direction coordinates) represents the spatial variables involved in transition modulation. In this patent, during vertical fusion... It is the coordinate of the porous layer thickness direction (e.g., z), in the circumferential / planar fusion. It is the spatial distance to a certain structural feature (such as the gas phase outlet); It is the transition center position, representing the center of symmetry of the longitudinal sigmoid function; It is a transition steepness control parameter, used to control the steepness of the longitudinal sigmoid curve. The larger the value, the steeper the transition and the narrower the transition zone; the longitudinal sigmoid function changes smoothly in the range of 0 to 1, so that the structure has no abrupt changes in geometry, maintains the continuous transport capacity of the liquid, and avoids the flow instability, drying or local blockage caused by traditional linear or step transitions.

[0078] Circumferential fusion unit: In this invention, a P-type or I-WP type TPMS structure is locally embedded in the phase change evaporation region to form a gas phase outlet region 301, and the D-type structure and the gas phase outlet region are smoothly fused in the circumferential direction through a distance-based sigmoid function, such as... Figure 11 and Figure 12 As shown, the distance-based sgmoid function expression is as follows: ;in, This is a distance-based sgmoid function; It is represented as the spatial distance from any point to the center of the target structure; The coordinates are the center of the target structure, that is, the center coordinates of the gas phase outlet region or local functional structure; The transition radius represents the characteristic distance from which the transition of the sgmoid function occurs. It can be understood as the boundary radius between the gas phase outlet structure and the surrounding evaporation structure. The distance-based sgmoid function can continuously modulate the TPMS function parameters according to the distance from each point to the center or boundary, so as to achieve a smooth circumferential geometric transition and avoid structural weakening and abrupt changes in steam flow caused by traditional mechanical opening or step transition.

[0079] Gradient porosity arrangement: This invention uses the smoothstep function to control the TPMS parameters along the thickness direction to achieve a continuous gradient of porosity from high to low in the porous layer. The expression for the smoothstep function is as follows: ;in, It is a dimensionless parameter used to describe the relative position of a structure or porosity along a spatial direction, without limiting its specific physical dimensions. , These are the spatial coordinates along the thickness direction. This is the starting point of the gradient (such as the bottom of the porous layer). This is the end position of the gradient (such as the top of the porous layer); compared with the Sigmoid function, the Smoothstep provides a smooth transition of C¹ in the finite interval [0,1], and the derivatives at both ends are zero. This ensures the smooth connection of the gradient TPMS at the porosity change boundary and avoids micro-stress concentration caused by the discontinuity of the first derivative.

[0080] Taking the liquid phase transport region unit as an example, such as Figure 13 As shown, when the porosity gradually decreases along the thickness direction, the TPMS unit structure undergoes the following geometric changes: 1) The channel cross-sectional area gradually shrinks: The channels in the high-porosity region at the bottom are wide, making it easy for liquid to enter. As the porosity decreases, the channels gradually narrow, and the flow velocity remains stable due to capillary force. 2) The pore wall thickness gradually increases: The decrease in porosity means an increase in the solid-phase volume ratio, resulting in increased pore wall thickness, which increases structural strength and enhances capillary suction, enabling spontaneous transport of liquid along the thickness direction. 3) The radius of curvature gradually decreases: As the porosity decreases, the local curvature of the channels increases, forming a region with higher capillary force, enhancing liquid adsorption and transport capabilities, and providing continuous liquid replenishment for the subsequent evaporation zone. 4) The liquid film spreading is controlled: The geometric change from wide to narrow channels is conducive to the gradual spreading of the liquid film in the evaporation zone, ensuring the stability of the liquid film in the evaporation zone and avoiding drying or excessive local liquid film thickness.

[0081] Furthermore, this invention addresses the problem of continuous coolant supply and phase change evaporation under sweating cooling conditions without external pumping. It proposes a self-extraction phase change sweating cooling porous structure based on TPMS topology integration and continuous gradient porosity control. This structure integrates multiple functional regions such as liquid phase transport, capillary liquid supply, phase change evaporation, and gas phase discharge within the same continuous porous layer. By smoothly modulating different TPMS configurations and porosities using a continuous function, a stable capillary pressure gradient and gas-liquid separation channel are constructed at the structural level, thereby achieving automatic coolant transport, stable evaporation, and smooth gas phase discharge.

[0082] Key technical features of this invention:

[0083] 1. Continuous gradient porosity porous layer design based on sweating cooling mechanism: The porous layer of the present invention is set with a continuous gradient distribution of gradually decreasing porosity along the thickness direction. Its design purpose is not simply to improve the mechanical properties of the structure, but to simulate the liquid supply path characteristics in the natural evaporation process, forming a capillary pressure gradient from the coolant supply side to the high temperature environment side inside the porous structure; through this continuous change in porosity, the spontaneous transport of coolant inside the porous layer can be realized without relying on external pumping, providing a continuous and stable liquid supply for sweating cooling conditions;

[0084] 2. Spatial partitioning and synergy of multifunctional TPMS configuration: This invention divides the porous layer along the thickness direction into: liquid phase transport region 1, liquid phase transport region 2, and phase change evaporation region 3. Each functional region uses different types of three-period minimal surface units (TPMS) as the dominant topological configuration. Among them, P-type TPMS is used to provide low-resistance overall liquid phase transport capability; G-type TPMS is used to enhance capillary action and realize stable liquid supply to the high-temperature side; D-type TPMS is used to increase specific surface area and curvature change, and enhance the phase change evaporation process. The above functional regions are not formed by simple stacking or splicing, but by continuous topological evolution within the same porous framework to achieve functional division and synergy.

[0085] 3. Vertical TPMS Structure Fusion Method Based on Continuous Functions: To avoid the problems of interface discontinuity, flow blockage, or local drying in traditional layered porous structures, this invention uses a sigmoid function to weighted modulate different TPMS implicit functions, achieving a smooth transition of different configurations in the thickness direction. This vertical fusion method results in: continuous change of pore morphology; gradual evolution of skeleton curvature and pore size; and natural transition of permeability and capillary force along the thickness direction; thereby constructing a stable and sustainable liquid transport path within the structure.

[0086] 4. Embedded gas phase outlet TPMS circumferential fusion design: Inside the phase change evaporation zone 3, the present invention locally sets up a gas phase outlet region 301 for discharging the gas phase working fluid generated by evaporation; this gas phase outlet region also adopts a TPMS topology configuration (preferably P-type or I-WP type), and is circumferentially continuously fused with the surrounding evaporation structure dominated by D-type through a sigmoid function based on spatial distance; compared with the traditional open or through-channel exhaust structure, this embedded gas phase outlet has: good structural continuity, does not destroy the overall skeleton; clear gas-liquid separation path; low steam discharge resistance, and is not prone to steam blockage.

[0087] 5. Geometric and capillary coupling effect caused by continuous gradient porosity: Taking liquid transport zone 1 as an example, as the porosity gradually decreases along the thickness direction, the structural geometric characteristics change simultaneously, including: the equivalent diameter of the pores gradually decreases; the thickness and curvature of the skeleton gradually increase; and the liquid-solid contact area per unit volume increases. These geometric changes collectively lead to a gradual increase in capillary pressure, enabling the coolant to form a self-driven transport capacity with a clear direction and stable strength within the porous structure, providing a reliable liquid source for the subsequent capillary supply zone and phase change evaporation zone.

[0088] Furthermore, the key protection points of this invention are: 1. The overall configuration of a continuous gradient porosity porous structure for self-pumped sweating cooling; 2. The TPMS configuration design concept that integrates liquid phase transport, capillary liquid supply, phase change evaporation and gas phase discharge functions within the same porous layer; 3. The method of smoothly integrating different TPMS units in the longitudinal and circumferential directions using continuous functions; 4. The embedded TPMS gas phase outlet structure and its continuous topological transition mode with the evaporation zone; 5. The capillary pressure gradient and spontaneous liquid transport mechanism caused by the continuous evolution of the structure.

[0089] In summary, even compared with the currently disclosed, best-performing sweating cooling porous structures and TPMS porous material design schemes, this invention still has the following significant and substantial technical advantages:

[0090] 1. From “parameter optimization” to “topology co-design”: 1) Limitations of existing best technologies: Existing technologies are mostly focused on optimizing parameters such as porosity, pore size or wettability of a single porous structure (such as a single TPMS, foam metal or fiber sintered body). Even if a gradient porosity is introduced, its structural topology remains single and its functional coupling ability is limited.

[0091] 2) Advantages of the present invention: The present invention introduces the functional partitioning collaborative design concept of multiple TPMS topologies (P / G / D) in the sweating cooling porous layer for the first time, and organically integrates different topologies through continuous fusion, so that key processes such as liquid transport, capillary liquid supply, and phase change evaporation are dominated by the most suitable topology, realizing "functional specialization + overall integration" from the structural level;

[0092] 2. Avoiding the problem of interface discontinuity in layered composite structures: 1) Limitations of existing best technologies: Even when using layered or composite porous media, existing solutions usually achieve structural switching through mechanical splicing, material replacement, or geometric abrupt changes, which can easily lead to: capillary force abrupt changes; permeability discontinuities; gas-liquid stagnation and local drying risks between layers; 2) Advantages of this invention: This invention is based on the continuous modulation of the implicit function of TPMS, and achieves smooth topological evolution of different structures in the longitudinal and circumferential directions through continuous functions such as sigmoid, avoiding any geometric abrupt changes or functional breaks, so that capillary pressure and flow resistance change continuously in space, fundamentally improving operational stability;

[0093] 3. Constructing a stable and self-sustaining capillary-driven transport mechanism: 1) Limitations of existing best technologies: Existing sweating cooling structures often rely on: external pumping; active control; or adjusting the liquid supply strategy when operating conditions change. Even with a self-suction design, the capillary driving force is usually insufficient or decays over time; 2) Advantages of this invention: This invention, through the synergistic effect of continuous gradient porosity and TPMS curvature evolution, forms a well-defined and stable capillary pressure gradient inside the porous layer, enabling the coolant to be automatically replenished under the drive of evaporation and consumption, exhibiting good self-regulation capability and long-term stability;

[0094] 4. More efficient and structurally intact gas phase discharge: 1) Limitations of existing best technologies: In existing solutions, gas phase discharge usually relies on: through holes; independent exhaust channels; or exhaust holes on the surface of the structure. These methods often destroy the overall structural integrity of the porous layer and easily cause gas-liquid flow interference; 2) Advantages of this invention: This invention embeds a gas phase outlet structure based on TPMS topology within the phase change evaporation zone and naturally transitions with the evaporation structure through a circumferential continuous fusion method, achieving: low-resistance, directional gas phase discharge; without destroying the continuity of the porous framework; and effectively suppressing vapor retention and blockage;

[0095] 5. Significantly improve system stability and service reliability: 1) Limitations of existing best technologies: Under long-term, high heat flux density conditions, existing structures generally suffer from cooling performance fluctuations, local failures, or structural degradation; 2) Advantages of this invention: Through topological continuous fusion, porosity gradient control, and gas phase channel optimization, this invention achieves a dynamic balance between liquid phase replenishment, evaporation consumption, and gas phase discharge at the structural level, thereby significantly improving the stability and reliability of the sweating cooling system under extreme conditions;

[0096] 6. Greater design freedom and engineering adaptability: 1) Limitations of existing best technologies: Traditional porous structures are difficult to enhance local functions without sacrificing overall performance; 2) Advantages of this invention: Based on the fusion design method of TPMS implicit function, the structure type, porosity gradient, gas phase outlet position and shape can be flexibly adjusted to adapt to different heat flow distributions and component geometries, and has significant engineering application potential, thus facilitating promotion and use.

[0097] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. All equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this invention should still be covered by the claims of this invention.

Claims

1. A TPMS self-extraction phase change sweating cooling porous structure, characterized in that: It includes a liquid phase transport zone (1) for initial entry and stable transport of coolant, a capillary supply zone (2) for continuously transporting coolant to the side near the high temperature environment by capillary action without external pump, and a phase change evaporation zone (3) for phase change evaporation and heat exchange of coolant, which are stacked sequentially along the thickness direction. The side of the liquid phase transport zone (1) away from the capillary supply zone (2) is close to the coolant supply side, and the side of the phase change evaporation zone (3) away from the capillary supply zone (2) is close to the high temperature environment side. Among them, a gas phase outlet region (301) for directional and low-resistance discharge of steam generated by phase change is embedded in a local area near the high temperature environment side of the phase change evaporation zone (3). The gas phase outlet region (301) can penetrate the phase change evaporation zone (3) in the thickness direction, and the gas phase outlet region (301) is discretely distributed or arrayed in the planar direction.

2. The TPMS self-extraction phase change sweating cooling porous structure according to claim 1, characterized in that: The liquid transport zone (1) adopts a P-type three-period minimal surface structure configuration, the capillary liquid supply zone (2) adopts a G-type three-period minimal surface structure configuration, the phase change evaporation zone (3) adopts a D-type three-period minimal surface structure configuration, and the gas phase outlet zone (301) adopts a P-type or I-WP-type three-period minimal surface structure configuration.

3. The TPMS self-extraction phase change sweating cooling porous structure according to claim 2, characterized in that: The implicit function expression of the P-type three-period minimal surface structure configuration is: cos(2πx)+cos(2πy)+cos(2πz)=0; The implicit function expression of the G-type three-period minimal surface structure configuration is: sin(2πx)cos(2πy)+sin(2πy)cos(2πz)+sin(2πz)cos(2πx)=0; The implicit function expression of the D-type three-period minimal surface structure configuration is: sin(2πx)sin(2πy)sin(2πz)+sin(2πx)cos(2πy)cos(2πz)+cos(2πx)sin(2πy)cos(2πz)+cos(2πx)cos(2πy)sin(2πz)=0; The implicit function expression of the I-WP type three-period minimal surface structure configuration is: 2[cos(2πx)cos(2πy)+cos(2πy)cos(2πz)+cos(2πz)cos(2πx)]-[cos(4πx)+cos(4πy)+cos(4πz)]=0; in, , , The three-dimensional spatial coordinate variables are used to construct the three-period minimal surface structure, which correspond to the spatial position parameters of the porous structure in three mutually orthogonal directions.

4. The TPMS self-suction phase change sweating cooling porous structure according to claim 1, characterized in that: A PG longitudinal fusion unit is provided between the liquid phase transport zone (1) and the capillary liquid supply zone (2), and a GD longitudinal fusion unit is provided between the capillary liquid supply zone (2) and the phase change evaporation zone (3). In the PG longitudinal fusion unit, the P-type three-period minimal surface structure configuration and the G-type three-period minimal surface structure configuration are smoothly fused in the longitudinal direction. In the GD longitudinal fusion unit, the G-type three-period minimal surface structure configuration and the D-type three-period minimal surface structure configuration are smoothly fused in the longitudinal direction.

5. The TPMS self-extraction phase change sweating cooling porous structure according to claim 4, characterized in that: Both the PG and GD longitudinal fusion units utilize a longitudinal sigmoid function to regulate the continuous change of the TPMS implicit function, achieving a smooth transition between different TPMS structural regions. The longitudinal sigmoid function changes smoothly within the 0-1 range, ensuring geometrically uniform structure and maintaining continuous liquid transport capability. Its functional expression is: ； in, For vertical sigmoid function; For spatial independent variables, it represents the spatial variables that participate in transition modulation; It is the transition center position, representing the center of symmetry of the longitudinal sigmoid function; It is a transition steepness control parameter used to control the steepness of the longitudinal sigmoid curve.

6. The TPMS self-extraction phase change sweating cooling porous structure according to claim 1, characterized in that: A circumferential fusion unit is provided between the phase change evaporation zone (3) and the gas phase outlet zone (301); in the circumferential fusion unit, the D-type three-period minimal surface structure configuration and the P-type or I-WP-type three-period minimal surface structure configuration are smoothly fused in the circumferential direction by the distance-based sigmoid function.

7. The TPMS self-extraction phase change sweating cooling porous structure according to claim 6, characterized in that: The distance-based sigmoid function can continuously modulate the TPMS function parameters according to the distance of each point from the center or boundary to achieve a smooth circumferential geometric transition. The expression of the distance-based sigmoid function is as follows: ； in, This is a distance-based sgmoid function; It is represented as the spatial distance from any point to the center of the target structure; The coordinates are the center of the target structure, that is, the center coordinates of the gas phase outlet region or local functional structure; The transition radius represents the characteristic distance from which the transition of the sgmoid function occurs.

8. A method for constructing a TPMS self-extraction phase change sweating cooling porous structure, characterized in that: The TPMS self-absorption phase change sweating cooling porous structure based on any one of claims 1-7 includes the following steps: The porous structure is constructed based on a unified TPMS implicit function system. Through continuous function modulation, it achieves geometric continuity and topological consistency among P-type three-period minimal surface structure configurations, G-type three-period minimal surface structure configurations, D-type three-period minimal surface structure configurations, and P-type or I-WP type three-period minimal surface structure configurations. By setting the TPMS parameters of each functional area, the porous layer as a whole forms a gradient distribution with the porosity gradually decreasing along the thickness direction. Among them, the liquid phase transport zone (1) has the highest porosity, the phase change evaporation zone (3) has the lowest porosity, the capillary liquid supply zone (2) has a porosity between the porosity of the liquid phase transport zone (1) and the phase change evaporation zone (3), and the gas phase outlet zone (301) has a higher porosity than the phase change evaporation zone (3).

9. A method for constructing a TPMS self-extraction phase change sweating cooling porous structure according to claim 8, characterized in that: The TPMS parameters along the thickness direction are adjusted by the smoothstep function to achieve a continuous gradient of porosity from high to low in the porous layer. The expression of the smoothstep function is as follows: ； in, It is a dimensionless parameter used to describe the relative position of a structure or porosity along a spatial direction.

Images