Ultrahigh-temperature heat rectification structure, ultrahigh-temperature heat rectification plate and 3D printing method

Abstract

The invention discloses an ultrahigh-temperature heat rectification structure, an ultrahigh-temperature heat rectification plate and a 3D printing method, and belongs to the technical field of heat rectification. The problem that an existing heat rectification device cannot achieve heat rectification under the ultra-high temperature condition is solved. The ultra-high-temperature thermal rectification structure is of a multi-layer gradient minimum curved surface hollow structure, gradient minimum curved surface initial unit cells used for achieving the ultra-high-temperature thermal rectification effect are marked as initial unit cells A, gradient minimum curved surface unit cells needing to be removed from the initial unit cells A are marked as removed unit cells Bi, i = 1, 2,..., k, and k is the number of the removed unit cells Bi; performing Boolean operation on the initial unit cell A and the removed unit cell Bi to obtain a multi-layer gradient minimum curved surface hollow structure; the initial unit cell A and the removed unit cell Bi are generated by two basic structures of the same type and different parameters. The device is mainly used for realizing ultrahigh-temperature heat rectification.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal rectification, and in particular relates to an ultra-high temperature thermal rectification structure, an ultra-high temperature thermal rectification plate and a 3D printing method. Background Art

[0002] Thermal rectification technology can regulate and control the thermal properties of materials or systems, thereby effectively improving the storage and transfer capacity of thermal energy. Through thermal rectification devices, directional and quantitative management of heat flow can be achieved, so that thermal energy can be fully utilized when needed, avoiding energy waste. Thermal rectification devices, such as thermal rectifiers, can be used in various energy systems to improve the thermal efficiency of the system. For example, in a solar power generation system, thermal rectification devices can help collect and store the thermal energy generated by solar energy, convert it into electrical energy or directly power electrical equipment. Similarly, in a wind power generation system, thermal rectification devices can also play a similar role and improve the overall efficiency of the wind power generation system.

[0003] At present, macro-scale thermal rectification devices cannot achieve thermal rectification effect under ultra-high temperature conditions. Summary of the invention

[0004] In view of this, the present invention provides an ultra-high temperature thermal rectification structure, an ultra-high temperature thermal rectification plate and a 3D printing method, which utilize at least two gradient minimal surface structures of the same type with different parameters to perform Boolean operations to obtain a multi-layer gradient minimal surface hollow structure to produce an efficient thermal rectification phenomenon.

[0005] The technical solution adopted by the present invention to solve the above technical problems is:

[0006] An ultra-high temperature thermal rectification structure is a multi-layered gradient minimal surface hollow structure, wherein the gradient minimal surface initial unit cell used to realize the ultra-high temperature thermal rectification effect is recorded as initial unit cell A, and the gradient minimal surface unit cell that needs to be removed from the initial unit cell A is recorded as removed unit cell B i , i=1,2,……,k, k is the number of cells B to be removed i The number of; the initial unit cell A and the removed unit cell B i Perform Boolean operations to obtain a multi-layer gradient minimal surface hollow structure; initial unit cell A and removed unit cell B i Generated for two base structures of the same type with different parameters.

[0007] Preferably, the initial unit cell A is a minimal surface unit cell whose volume fraction increases linearly from bottom to top, and the volume fraction of the initial unit cell A is a gradient from m to n from bottom to top, where m is greater than n; the removal of the unit cell B i The volume fraction of the minimal surface unit cell increases linearly from bottom to top. Remove the unit cell B i The volume fraction from bottom to top is M i To Ni The gradient of N i Greater than M i ; m-∑M i >0, n-∑N i >0,(m-∑M i )-(n-∑N i )>0,M i >M i+1 , N i >N i+1 .

[0008] Preferably, the initial unit cell A and the removed unit cell Bi are one of IWP type, Gyroid type, Primitive type, Dimond type and S type minimal surfaces.

[0009] Preferably, the initial unit cell A and the removed unit cell Bi are of Gyroid type.

[0010] Preferably, the ultra-high temperature thermal rectification structure is made of ceramic material.

[0011] Preferably, the ultra-high temperature thermal rectification structure is silicon oxide ceramic.

[0012] Preferably, the thermal conductivity of the silicon oxide ceramic is 0.9-1.4 W / (m·K).

[0013] An ultra-high temperature heat rectifying plate comprises an upper plate, a lower plate and an ultra-high temperature heat rectifying structure, wherein the upper plate and the lower plate clamp the ultra-high temperature heat rectifying structure.

[0014] A 3D printing method for an ultra-high temperature thermal rectifying structure, preparing the ultra-high temperature thermal rectifying structure, the preparation steps are as follows:

[0015] S1, design the model of multi-layer gradient minimal surface hollow structure using 3D modeling software;

[0016] S2, preparing silicon oxide ceramic printing slurry;

[0017] S3, for 3D printing, first import the printing model data into the software designed for the printer, slice the model, and start printing after leveling;

[0018] S4, after printing is completed, the printed body is sintered, and the firing is performed in a cycle of heating and heat preservation until a multi-layer gradient minimal surface hollow structure is obtained.

[0019] Preferably, in S4, during the sintering process, the heating rate is 0.5-2°C / min, the holding time is 60 minutes, and the total sintering time is 2-3 days.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention uses the gradient minimum surface initial unit cell A and the gradient minimum surface removal unit cell B for realizing the ultra-high temperature thermal rectification effect. i Boolean operations are performed to obtain a multi-layered gradient minimal surface hollow structure; under high-temperature heat transfer conditions, the radiation heat transfer inside the structure and the heat conduction of the gradient structure produce an asymmetric coupling, thereby producing an efficient thermal rectification phenomenon. The structure can achieve a thermal rectification effect at a maximum temperature of 2000°C, and the structure can be designed in a large plate shape with a fixed normal size to meet the requirements of thermal rectification areas of any area.

[0022] 2. The ultra-high temperature heat rectifying structure of the present invention uses silicon oxide ceramics as heat-resistant materials. The combination of silicon oxide ceramic materials and multi-layer minimal curved hollow structures can greatly enhance the radiation heat transfer effect inside the structure at ultra-high temperatures. After coupling with gradient thermal conductivity, an asymmetric heat transfer effect will be generated, that is, the heat transferred by the structure in two opposite directions is different.

[0023] 3. Through periodic design of multi-layer gradient minimal surface hollow structures, large-sized thermal rectification plates can be constructed, which can not only provide efficient thermal rectification effects, but also provide excellent mechanical properties and structural stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are incorporated as part of this application and are used to provide a further understanding of the present invention.

[0025] Figure 1 The construction process of a double-layer gradient minimal surface hollow structure with a volume fraction of 85%-10% gradient of 1*1*1 is composed of an initial unit cell A with a volume fraction of 90%-20% gradient from bottom to top and a removed unit cell B with a volume fraction of 5%-10% gradient from bottom to top. i Do Boolean operations to get .

[0026] Figure 2 The construction process of a double-layer gradient minimal surface hollow structure with a volume fraction of 85%-10% gradient for 1*1*3 is composed of an initial unit cell A with a volume fraction of 90%-20% gradient from bottom to top and a removed unit cell B with a volume fraction of 5%-10% gradient from bottom to top. i Do Boolean operations to get .

[0027] Figure 3 The construction process of a double-layer gradient minimal surface hollow structure with a volume fraction of 85%-10% gradient for 10*10*2 is composed of an initial unit cell A with a volume fraction of 90%-20% gradient from bottom to top and a removed unit cell B with a volume fraction of 5%-10% gradient from bottom to top. i Do Boolean operations to get .

[0028] Figure 4 It is a 5*5*10 double-layer gradient minimal surface hollow structure in the rectangular coordinate system.

[0029] Figure 5 It is a 5*5*10 double-layer gradient minimal surface hollow structure in the cylindrical coordinate system.

[0030] Figure 6 The figure is a schematic diagram of the structure of an ultra-high temperature thermal rectifier plate. DETAILED DESCRIPTION

[0031] The present invention is described in detail below in conjunction with specific embodiments.

[0032] Thermal rectification devices are mainly made of nonlinear materials and phase change materials, or are realized with the help of thermal convection effect. This type of design has the following limitations: (1) It is difficult to find nonlinear materials or phase change materials that are resistant to high temperatures in reality, especially in environments greater than 1000 degrees Celsius. It is difficult to find materials that are both resistant to high temperatures and have sufficiently strong nonlinear thermal conductivity. This seriously limits the development of ultra-high temperature thermal rectification technology. (2) The thermal convection effect requires that the liquid be enclosed in a closed space and that a mechanical device be used to allow the liquid to flow. Under ultra-high temperature conditions, a liquid-gas phase change will occur, which makes the convection device unable to work under ultra-high temperature conditions. (3) In the past, thermal rectification structures relied on phase change materials or nonlinear materials. Under the condition that the normal size of the action plane is fixed, the in-plane size of the rectification unit is limited. For large areas with rectification requirements, thermal rectification can only be achieved by arranging multiple units, and the imperfect contact between the units will inevitably affect the overall thermal rectification effect.

[0033] To solve the above technical problems, see Figures 1 to 5 The embodiment of the present application provides an ultra-high temperature thermal rectification structure, which can achieve a thermal rectification effect at a maximum temperature of 2000°C, and the structure can be designed in a large plate shape under the premise of a fixed normal dimension to meet the requirements of a thermal rectification area of ​​any area. The ultra-high temperature thermal rectification structure is a multi-layered gradient minimal surface hollow structure. The initial unit cell of the gradient minimal surface used to achieve the ultra-high temperature thermal rectification effect is denoted as initial unit cell A, and the gradient minimal surface unit cell that needs to be removed from the initial unit cell A is denoted as removed unit cell B. i , i=1,2,……,k, k is the number of cells B to be removed i The number of initial cells A and removed cells B i Generate two basic structures of the same type with different parameters. i Boolean operation is performed to obtain a multi-layer gradient minimal surface hollow structure; due to the initial unit cell A and the removal of unit cell B iBoth are gradient minimal surface structures. After Boolean operations are performed on the two, the obtained structure is also a gradient minimal surface structure, and multiple layers of gradient minimal surface cavities are formed inside the initial unit cell A. Under high temperature heat transfer conditions, the radiation heat transfer inside the structure and the heat conduction of the gradient structure produce asymmetric coupling, thereby producing efficient thermal rectification. The number of layers of the minimal surface cavity is related to the removal of unit cell B. i The number of Figures 1 to 5 As shown, when i=1, that is, when one unit cell is removed, the number of layers of the minimal surface cavity is 1, forming a double-layer gradient minimal surface hollow structure; when i=2, the number of layers of the minimal surface cavity is 2, forming a three-layer gradient minimal surface hollow structure, and so on.

[0034] Wherein, the initial unit cell A is a minimal surface unit cell with a linearly increasing volume fraction from bottom to top (when air is used as a reference substance, the relative density classification of the unit cell material), and the volume fraction of the initial unit cell A is a gradient from m to n from bottom to top, where m is greater than n; Figures 1 to 3 Taking the initial unit cell A in the three figures as an example, the initial unit cell A in the three figures is a unit cell whose volume fraction decreases from 90% to 20% from bottom to top. However, since the heights of the initial unit cell A in the three figures are different, the volume fraction decreases linearly with the increase of the height, and the volume fraction can be reduced from 90% to 20%. i The volume fraction of the minimal surface unit cell increases linearly from bottom to top. Remove the unit cell B i The volume fraction from bottom to top is M i To N i The gradient of N i Greater than M i ;by Figures 1 to 3 Removal of single cell B i For example, the removed unit cells Bi in the three figures are all units whose volume fraction increases from 5% to 10% from bottom to top. However, since the heights of the removed unit cells Bi in the three figures are different, the volume fraction increases linearly with the increase of height, and the volume fraction can be increased from 5% to 10%. Since it is necessary to form multi-layer cavities inside the obtained minimal surface structure and form a gradient in the height direction after Boolean operation on the initial unit cell A and the removed unit cell Bi, the following relationship needs to be satisfied: m-∑M i >0, n-∑N i >0,(m-∑M i )-(n-∑N i )>0, and M i >M i+1 , N i >N i+1 .

[0035] Wherein, the initial unit cell A and the removed unit cell Bi It is one of the IWP type, Gyroid type, Primitive type, Dimond type and S type minimal surface. In order to ensure a sufficiently strong longitudinal (heat transfer direction) radiation intensity, the Gyroid type is preferred.

[0036] The ultra-high temperature thermal rectification structure is made of ceramic material, preferably silicon oxide ceramic, and the thermal conductivity of the silicon oxide ceramic is 0.9-1.4W / (m·K). In order to achieve the purpose of thermal rectification under ultra-high temperature conditions, it is necessary not only to meet the functionality of the structure, but also to meet the "heat resistance" of the material, so we choose ceramic material as the "heat-resistant material". Taking into account the coupling effect of thermal conductivity and radiation heat transfer effect, in actual operation, we choose silicon oxide ceramic 0.9-1.4W / (m·K) as the heat-resistant material. The combination of silicon oxide ceramic material and multi-layer minimal surface hollow structure can greatly enhance the radiation heat transfer effect inside the structure at ultra-high temperature. After coupling with gradient thermal conductivity, it will produce an asymmetric heat transfer effect, that is, the heat transferred by the structure in two relative directions is different.

[0037] like Figure 6 As shown, this embodiment provides an ultra-high temperature heat rectifying plate, including an upper plate, a lower plate and an ultra-high temperature heat rectifying structure, wherein the upper plate and the lower plate clamp the ultra-high temperature heat rectifying structure. By periodically designing the multi-layer gradient minimal surface hollow structure, a large-sized heat rectifying plate can be constructed, which can not only provide an efficient heat rectifying effect, but also provide excellent mechanical properties and structural stability.

[0038] A 3D printing method for an ultra-high temperature thermal rectifying structure, preparing the ultra-high temperature thermal rectifying structure, the preparation steps are as follows:

[0039] S1, design the model of multi-layer gradient minimal surface hollow structure using 3D modeling software;

[0040] S2, preparing silicon oxide ceramic printing slurry;

[0041] S3, for 3D printing, first import the printing model data into the software designed for the printer, slice the model, and start printing after leveling;

[0042] S4, after printing is completed, the printed body is sintered in a cycle of heating and heat preservation until a multi-layer gradient minimal surface hollow structure is obtained; during the sintering process, the heating rate is 0.5-2°C / min, the heat preservation time is 60 minutes, and the total sintering time is 2-3 days.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. An ultra-high temperature thermal rectification structure, characterized in that: It is a multi-layered gradient minimal surface hollow structure. The initial unit cell of the gradient minimal surface used to achieve the ultra-high temperature thermal rectification effect is recorded as the initial unit cell A, and the gradient minimal surface unit cell that needs to be removed from the initial unit cell A is recorded as the removed unit cell B. i , i=1,2,……,k, k is the number of cells B to be removed i The number of; the initial unit cell A and the removed unit cell B i Perform Boolean operations to obtain a multi-layer gradient minimal surface hollow structure; initial unit cell A and removed unit cell B i Generated for two base structures of the same type with different parameters.

2. The ultra-high temperature thermal rectification structure according to claim 1, characterized in that: The initial unit cell A is a minimal surface unit cell with a linearly increasing volume fraction from bottom to top, and the volume fraction of the initial unit cell A is a gradient from m to n from bottom to top, and m is greater than n; the removal of the unit cell B i The volume fraction of the minimal surface unit cell increases linearly from bottom to top. Remove the unit cell B i The volume fraction from bottom to top is M i To N i The gradient of N i Greater than M i ; m-∑M i >0, n-∑N i >0,(m-∑M i )-(n-∑N i )>0,M i >M i+1 , N i >N i+1 .

3. The ultra-high temperature thermal rectification structure according to claim 1, characterized in that: The initial unit cell A and the removed unit cell Bi are one of IWP type, Gyroid type, Primitive type, Dimond type and S type minimal surfaces.

4. The ultra-high temperature thermal rectification structure according to claim 3, characterized in that: The initial unit cell A and the removed unit cell Bi are of Gyroid type.

5. The ultra-high temperature thermal rectification structure according to claim 1, characterized in that: The ultra-high temperature thermal rectification structure is made of ceramic material.

6. The ultra-high temperature heat rectifying structure according to claim 5, characterized in that: The ultra-high temperature thermal rectification structure is made of silicon oxide ceramic.

7. The ultra-high temperature heat rectifying structure according to claim 6, characterized in that: The thermal conductivity of the silicon oxide ceramic is 0.9-1.4 W / (m·K).

8. An ultra-high temperature heat rectifier plate, characterized in that: It comprises an upper plate, a lower plate and an ultra-high temperature thermal rectification structure as claimed in any one of claims 1 to 7, wherein the upper plate and the lower plate clamp the ultra-high temperature thermal rectification structure.

9. A 3D printing method for an ultra-high temperature thermal rectifier structure, characterized in that: The ultra-high temperature thermal rectification structure as claimed in claim 7 is prepared by the following steps: S1, design the model of multi-layer gradient minimal surface hollow structure using 3D modeling software; S2, preparing silicon oxide ceramic printing slurry; S3, for 3D printing, first import the printing model data into the software designed for the printer, slice the model, and start printing after leveling; S4, after printing is completed, the printed body is sintered, and the firing is performed in a cycle of heating and heat preservation until a multi-layer gradient minimal surface hollow structure is obtained.

10. A 3D printing method for an ultra-high temperature thermal rectifying structure according to claim 9, characterized in that: In the S4, during the sintering process, the heating rate is 0.5-2°C / min, the heat preservation time is 60 minutes, and the total sintering time is 2-3 days.

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