A composite porous structure for thermal management and a method of making

Abstract

The application provides a composite porous structure for thermal management and a preparation method, and the composite porous structure comprises an external sweating porous layer and an internal support framework; the thickness of the external sweating porous layer is 2-20 mm, the internal sweating porous layer contains three-dimensional micrometer-sized pores, the pore diameter is 20-200 mu m, and the porosity is 10%-50%; the support framework adopts a TPMS lattice framework, the lattice unit size is 5-10 mm, and the lattice wall thickness is 0.3-1.5 mm; three-dimensional interconnected pores are formed in the internal TPMS lattice framework, the cooling medium is transmitted through the three-dimensional interconnected pores of the lattice framework, and sweating cooling is implemented through the sweating porous layer. The application integrates the design of the TPMS lattice framework in the internal sweating structure, forms a micro-macro composite porous structure of'sweating porous + TPMS lattice porous', realizes the integrated design of the structure function of thermal protection-supporting thermal management, and is prepared in the mode of additive manufacturing, so that the efficiency of the thermal management system in the fields of aviation, aerospace, automobiles, nuclear power and the like is improved.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology, and specifically relates to a composite porous structure for thermal management and its preparation method, which is applicable to thermal management in industries such as aerospace, automotive, and nuclear power. Background Technology

[0002] Sweating cooling is a biomimetic technology that mimics the body's temperature regulation process by imitating the sweating of biological surfaces. Forced sweating cooling refers to the process where gaseous or liquid coolant, under a certain driving pressure, permeates through microporous channels within a layered or porous media structure to the hot-end surface, forming a continuous and stable coolant boundary layer. Traditional sweating cooling structures have a certain cooling effect, but due to their poor strength and toughness, they cannot withstand large external loads.

[0003] Currently, the sweating cooling structure mainly consists of an external sweating layer, a medium channel, and a load-bearing solid layer. The cooling medium is transported to the external sweating layer through the medium channel. However, the channel distribution area is limited and the transmission channel travel is relatively long, resulting in problems such as uneven medium transmission and slow response. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, the inventors have conducted intensive research and provided a composite porous structure for thermal management and its preparation method. By integrating a TPMS lattice framework into the sweating structure, a micro-macro composite porous structure of "sweat-producing porous structure + TPMS lattice porous structure" is formed, realizing the integrated design of thermal protection and load-bearing thermal management structure. The structure is prepared by additive manufacturing, thereby improving the efficiency of thermal management systems in aerospace, automotive, nuclear power and other industrial fields.

[0005] The technical solution provided by this invention is as follows:

[0006] In a first aspect, a composite porous structure for thermal management includes an outer sweating porous layer and an inner supporting skeleton; the outer sweating porous layer has a thickness of 2-20 mm, contains micron-level three-dimensional pores with a pore diameter of 20-200 μm and a porosity of 10%-50%.

[0007] The supporting framework adopts a TPMS lattice framework with a lattice unit size of 5-10mm and a lattice wall thickness of 0.3-1.5mm. Three-dimensional interconnected pores are formed inside the TPMS lattice framework. The cooling medium is transported through the three-dimensional interconnected pores of the lattice framework and sweating cooling is implemented through the sweating porous layer.

[0008] Secondly, a method for preparing a composite porous structure for thermal management is provided, wherein the composite porous structure is prepared by laser selective melting forming technology.

[0009] The composite porous structure includes an outer sweating porous layer and an inner supporting framework. The outer sweating porous layer has a thickness of 2-20 mm and contains micron-sized three-dimensional pores with a diameter of 20-200 μm and a porosity of 10%-50%. The supporting framework adopts a TPMS lattice framework, in which three-dimensional interconnected pores are formed. The cooling medium is transported through the three-dimensional interconnected pores of the lattice framework, and sweating cooling is achieved through the sweating porous layer.

[0010] The process parameters for forming a sweat-inducing porous layer include: laser power 280-320W, scanning speed 800-1200mm / s, layer thickness 0.03-0.04mm, scanning spacing 0.12-0.20mm, and interlayer phase angle 67°.

[0011] The process parameters for forming the support skeleton include: laser power 300-360W, scanning speed 600-700mm / s, layer thickness 0.03-0.04mm, scanning spacing 0.07-0.10mm, and interlayer phase angle 67°.

[0012] The present invention provides a composite porous structure for thermal management and a method for its preparation, which has the following characteristics:

[0013] Beneficial effects:

[0014] This invention provides a composite porous structure for thermal management and its preparation method. By integrating a TPMS lattice framework into the sweating structure, a micro-macro composite porous structure of "sweat-producing porous structure + TPMS lattice porous structure" is formed, realizing the integrated design of thermal protection and load-bearing thermal management structure. The structure is prepared by additive manufacturing, thereby improving the efficiency of thermal management systems in aerospace, automotive, nuclear power and other industrial fields. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a composite porous structure for thermal management according to the present invention. Detailed Implementation

[0016] The features and advantages of the present invention will become clearer and more apparent from the following detailed description.

[0017] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0018] This invention provides a composite porous structure for thermal management, comprising an outer sweating porous layer and an inner supporting skeleton; the outer sweating porous layer has a thickness of 2-20 mm, contains micron-level three-dimensional pores with a pore diameter of 20-200 μm and a porosity of 10%-50%;

[0019] The supporting framework adopts a three-period distributed minimal curved surface structure, namely the TPMS lattice framework, with a lattice unit size of 5-10 mm and a lattice wall thickness of 0.3-1.5 mm. Three-dimensional interconnected pores are formed inside the framework, and the cooling medium is transported through the three-dimensional interconnected pores of the lattice framework, and finally sweating cooling is implemented through the sweating porous layer.

[0020] The TPMS lattice framework is designed by implicit function definition, and the lattice cells adopt minimal surfaces such as Schwarz P, Schwarz D, Gyroid, IWP, Neovius, and Lidinoid.

[0021] Triple Periodic Minimal Surface (TPMS) is a periodic implicit surface with zero average curvature. The surface is smooth and the pores are three-dimensionally interconnected. The overall structure can be precisely controlled by implicit functions and can be designed as a high specific surface area, three-dimensionally continuous, smooth flow channel surface. By integrating a TPMS lattice framework within the sweating structure, a micro-macro composite porous structure of "sweat-producing pores + TPMS lattice pores" is formed. The micron-level sweat-producing pores provide the thermal function of sweat cooling, while the millimeter-level lattice pores provide structural load-bearing and cooling medium transport, ultimately achieving an integrated design of load-bearing and thermal protection thermal management structures.

[0022] The selection of TPMS lattice framework is not only due to its structural load-bearing function, but also because the TPMS lattice framework has a smooth surface and highly interconnected pores, which helps the cooling medium to be transported quickly and evenly to the sweating porous layer, further improving the uniformity and response speed of sweating cooling.

[0023] The composite porous structure in this invention can be used as a thermal protection structure for the hot end of an aircraft, or it can be processed into an aircraft shell. The composite porous structure faces harsh thermal environments, requiring it to have extremely strong thermal protection performance. Therefore, this invention features a specific structural design for the outer sweat-absorbing porous layer and the internal supporting skeleton. The thickness of the sweat-absorbing porous layer is 2-20 mm, the pore diameter is 20-200 μm, and the porosity is 10%-50%. Preferably, the thickness of the outer sweat-absorbing porous layer is 2-12 mm, the pore diameter is 20-120 μm, and the porosity is 10%-30%.

[0024] The design of the thickness of the sweating porous layer needs to consider both the sweating effect and mechanical properties. If the thickness is too small and less than the minimum value of the above range, the sweating will be too fast, resulting in ineffective waste of the medium. At the same time, the mechanical properties will be too low, leading to product deformation, cracking and failure. If the thickness is too large and greater than the maximum value of the above range, the sweating effect will be insignificant.

[0025] The design of the pore diameter of the sweating porous layer takes into account the flow resistance of the pores and the permeability of the medium. If the pore diameter is too small and less than the minimum value of the above range, the pore flow resistance will be too large and the permeability of the medium will be unsatisfactory. If the pore diameter is too large and greater than the maximum value of the above range, the pore flow resistance will be too small and the storage capacity of the medium will be poor.

[0026] The design of the porosity of the sweating porous layer takes into account both the sweating effect and mechanical properties. If the porosity is too small and less than the minimum value of the above range, the sweating effect will be unsatisfactory. If the porosity is too large and greater than the maximum value of the above range, the product's mechanical properties will be poor and the medium's storage properties will be poor.

[0027] In this invention, the lattice unit size of the supporting framework is 5-10 mm, and the lattice wall thickness is 0.3-1.5 mm; preferably, the lattice unit size of the supporting framework is 5-8 mm, and the lattice wall thickness is 0.3-1.0 mm.

[0028] The design of the supporting framework lattice unit size takes into account the dielectric transport and mechanical properties. If the lattice unit size is too small and smaller than the minimum value of the above range, the dielectric transport will be poor. If the lattice unit size is too large and larger than the maximum value of the above range, the mechanical properties will be poor and the load-bearing effect will be unsatisfactory.

[0029] The design of the supporting framework lattice wall thickness takes into account processability, dielectric transportability, and mechanical properties. If the lattice wall thickness is too small and less than the minimum value of the above range, the processability will be poor, the mechanical properties of the product will be low, and the load-bearing capacity will be affected. If the lattice wall thickness is too large and greater than the maximum value of the above range, the dielectric transportability will be poor.

[0030] In this invention, the composite porous structure can be prepared using metallic materials such as TA15, TC4, GH4169, GH4099, CuCrZr, CuCrNb, AlSi10Mg, and AlMgScZr.

[0031] This invention also provides a method for preparing a composite porous structure for thermal management, comprising:

[0032] Step 1) Design of a porous sweating layer structure

[0033] The sweating porous layer is 2-20 mm thick and contains micron-sized three-dimensional pores with a pore diameter of 20-200 μm and a porosity of 10%-50%.

[0034] Step 2) Support frame design

[0035] The supporting framework employs a three-period distributed minimal surface structure, namely the TPMS lattice framework, with three-dimensional interconnected pores forming within the framework. The cooling medium is transported through these three-dimensional interconnected pores. The lattice cells can utilize minimal surfaces such as Schwarz P, Schwarz D, Gyroid, IWP, Neovius, and Lidinoid, with lattice unit sizes of 5-10 mm and lattice wall thicknesses of 0.3-1.5 mm.

[0036] Step 3) Determine the composite porous structure material

[0037] Composite porous structures can be manufactured using metallic materials such as TA15, TC4, GH4169, GH4099, CuCrZr, CuCrNb, AlSi10Mg, and AlMgScZr.

[0038] Step 4) Preparation of composite porous structure

[0039] Fabrication of composite porous structures using laser selective melting forming technology:

[0040] The process parameters for forming a sweat-inducing porous layer include: laser power 280-320W, scanning speed 800-1200mm / s, layer thickness 0.03-0.04mm, scanning spacing 0.12-0.20mm, and interlayer phase angle 67°.

[0041] The process parameters for forming the support skeleton include: laser power 300-360W, scanning speed 600-700mm / s, layer thickness 0.03-0.04mm, scanning spacing 0.07-0.10mm, and interlayer phase angle 67°.

[0042] Step 5) After the forming is completed, the composite porous structure is subjected to post-processing such as powder cleaning, heat treatment, and wire cutting.

[0043] Example

[0044] Example 1

[0045] The product uses GH4169 high-temperature alloy material, with a sweating porous layer thickness of 5mm, a pore diameter of 50μm, and a porosity of 20%; the support skeleton adopts the Gyroid minimal curved surface type, with a support skeleton lattice unit size of 6mm and a support skeleton lattice wall thickness of 0.6mm.

[0046] The product was heated using a quartz lamp to assess its sweating and cooling effect. After activating the sweating and cooling mechanism, the peak temperature of the product decreased from the theoretically predicted 700℃ without sweating to approximately 170℃ with sweating, achieving a temperature drop of 530℃. The tensile strength of the product's porous sweating layer is 300MPa, and the tensile strength of the internal supporting skeleton is 500MPa.

[0047] Comparative Examples 1-2

[0048] The comparative examples 1-2 are identical to Example 1, except that the thickness of the sweating porous layer is 1 mm and 25 mm respectively.

[0049] The porous layer of the 1mm thick product deformed and cracked under 40MPa, causing the product to fail; the cooling medium of the 25mm thick product had difficulty seeping out, and the temperature drop due to sweating cooling was only 125℃.

[0050] Comparative Examples 3-4

[0051] The comparative examples 3-4 are identical to Example 1, except that the pore diameters of the sweating porous layers are 10 μm and 400 μm.

[0052] Products with 10μm pore diameters have difficulty allowing the cooling medium to seep out, and the temperature drop during sweating cooling is only 85℃; products with 400μm pore diameters exhibit water seepage / leaking, and cannot form a stable sweating cooling effect.

[0053] Comparative Examples 5-6

[0054] The comparative examples 5-6 are identical to Example 1, except that the porosity of the sweating porous layer is 5% and 60% respectively.

[0055] Products with 5% porosity have difficulty allowing the cooling medium to seep out, and the temperature drop due to sweating is only 55°C; products with 60% porosity cannot store the medium and naturally seep out under no pressure.

[0056] Comparative Examples 7-8

[0057] The comparative examples 7-8 are identical to Example 1, except that the lattice unit size of the supporting framework is 3mm and 12mm.

[0058] Products with a lattice unit size of 3mm have high medium flow resistance and a temperature drop of only 65℃ when evaporating for cooling; products with a lattice unit size of 12mm have an internal support skeleton with a tensile strength of only 300MPa, and their mechanical properties cannot meet the requirements for use.

[0059] Comparative Examples 9-10

[0060] The comparative examples 9-10 are identical to Example 1, except that the lattice wall thickness of the supporting framework is 0.2 mm and 1.8 mm.

[0061] Products with a lattice wall thickness of 0.2mm have poor lattice formation, and the tensile strength of the internal supporting skeleton is only 120MPa, which cannot meet the mechanical properties required for use. Products with a lattice wall thickness of 1.8mm have difficulty in the seepage of cooling medium, and the temperature drop due to sweating cooling is only 45℃.

[0062] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0063] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A composite porous structure for thermal management, characterized in that, It includes an outer sweat-absorbing porous layer and an internal support skeleton; the outer sweat-absorbing porous layer has a thickness of 2-20 mm, contains micron-level three-dimensional pores with a pore diameter of 20-200 μm, and a porosity of 10%-50%; The supporting framework adopts a TPMS lattice framework, and three-dimensional interconnected pores are formed inside the TPMS lattice framework. The cooling medium is transported through the three-dimensional interconnected pores of the lattice framework and sweating cooling is implemented through the sweating porous layer. The lattice unit size of the TPMS lattice framework is 5-10mm and the lattice wall thickness is 0.3-1.5mm.

2. The composite porous structure for thermal management according to claim 1, characterized in that, The lattice cells of the TPMS lattice framework are Schwarz P, Schwarz D, Gyroid, IWP, Neovius, or Lidinoid minimal surfaces.

3. The composite porous structure for thermal management according to claim 1, characterized in that, The composite porous structure is prepared using TA15, TC4, GH4169, GH4099, CuCrZr, CuCrNb, AlSi10Mg, or AlMgScZr metallic materials.

4. A method for preparing a composite porous structure for thermal management, characterized in that, Composite porous structures were prepared using laser selective melting forming technology. The composite porous structure comprises an outer sweat-absorbing porous layer and an inner supporting framework; the outer sweat-absorbing porous layer has a thickness of 2-20 mm, contains micron-level three-dimensional pores with a pore diameter of 20-200 μm, and a porosity of 10%-50%; The supporting framework adopts a TPMS lattice framework, and three-dimensional interconnected pores are formed inside the TPMS lattice framework. The cooling medium is transported through the three-dimensional interconnected pores of the lattice framework and sweating cooling is implemented through the sweating porous layer. The lattice unit size of the TPMS lattice framework is 5-10mm and the lattice wall thickness is 0.3-1.5mm.

5. The method for preparing a composite porous structure for thermal management according to claim 4, characterized in that, The lattice cells of the TPMS lattice framework are Schwarz P, Schwarz D, Gyroid, IWP, Neovius, or Lidinoid minimal surfaces.

6. The method for preparing a composite porous structure for thermal management according to claim 4, characterized in that, The composite porous structure is prepared using TA15, TC4, GH4169, GH4099, CuCrZr, CuCrNb, AlSi10Mg, or AlMgScZr metallic materials.

7. The method for preparing a composite porous structure for thermal management according to claim 4, characterized in that, The process parameters for forming a sweat-inducing porous layer include: laser power 280-320W, scanning speed 800-1200mm / s, layer thickness 0.03-0.04mm, scanning spacing 0.12-0.20mm, and interlayer phase angle 67°.

8. The method for preparing a composite porous structure for thermal management according to claim 4, characterized in that, The process parameters for forming the support skeleton include: laser power 300-360W, scanning speed 600-700mm / s, layer thickness 0.03-0.04mm, scanning spacing 0.07-0.10mm, and interlayer phase angle 67°.

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