An ultrahigh-temperature hot rectification structure, an ultrahigh-temperature hot rectification plate and a 3D printing method

Abstract

The application discloses an ultrahigh-temperature thermal rectification structure, an ultrahigh-temperature thermal rectification plate and a 3D printing method, and belongs to the technical field of thermal rectification. In order to solve the problem that the existing thermal rectification device cannot realize thermal rectification under ultrahigh-temperature conditions, the ultrahigh-temperature thermal rectification structure is a multilayer gradient minimal surface hollow structure, the gradient minimal surface initial cell for realizing the ultrahigh-temperature thermal rectification effect is recorded as initial cell A, and the gradient minimal surface cell which needs to be removed in the initial cell A is recorded as removal cell B i , i = 1, 2, …, k, k is the number of removal cells B i ; the initial cell A and the removal cell B i are subjected to Boolean operation to obtain the multilayer gradient minimal surface hollow structure; the initial cell A and the removal cell B i are generated from two basic structures of the same type and different parameters. The application is mainly used for realizing ultrahigh-temperature thermal rectification.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of thermal rectification, and particularly relates to an ultrahigh-temperature thermal rectification structure, an ultrahigh-temperature thermal rectification plate and a 3D printing method. BACKGROUND

[0002] Thermal rectification technology can adjust and control the thermal performance of materials or systems, thereby effectively improving the storage and transmission 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 applied 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, converting it into electrical energy or directly powering electrical equipment. Similarly, in a wind power generation system, thermal rectification devices can also play a similar role, improving the overall efficiency of the wind power generation system.

[0003] At present, macro-scale thermal rectification devices cannot achieve thermal rectification effect under ultrahigh-temperature conditions. SUMMARY

[0004] Therefore, the application provides an ultrahigh-temperature thermal rectification structure, an ultrahigh-temperature thermal rectification plate and a 3D printing method, which uses at least two gradient minimal surface structures of the same type but different parameters to perform Boolean operation to obtain a multi-layer gradient minimal surface hollow structure, so as to generate efficient thermal rectification phenomenon.

[0005] The technical scheme adopted by the application to solve the above technical problems is as follows:

[0006] An ultrahigh-temperature thermal rectification structure is a multi-layer gradient minimal surface hollow structure. A gradient minimal surface initial cell used to achieve ultrahigh-temperature thermal rectification effect is recorded as initial cell A, and a gradient minimal surface cell that needs to be removed in the initial cell A is recorded as removal cell B. i , i = 1, 2, …, k, k is the number of removal cells B i ; the initial cell A and the removal cell B i are subjected to Boolean operation to obtain a multi-layer gradient minimal surface hollow structure; and the initial cell A and the removal cell B i are two basic structures of the same type but different parameters.

[0007] Preferably, the initial cell A is a minimal surface cell with linearly increasing volume fraction from bottom to top, and the volume fraction of the initial cell A is a gradient of m to n from bottom to top, wherein m is greater than n; and the removal cell B i is a minimal surface cell with linearly increasing volume fraction from bottom to top, and the volume fraction of the removal cell B i is a gradient of M i to N from bottom to top.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 .

[0008] Preferably, the initial unit cell A and the removed unit cell Bi are one of the following: IWP type, Gyroid type, Primitive type, Diamond type and S-type minimal surface.

[0009] Preferably, the initial cell A and the removed cell Bi are of the 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 made of silicon oxide ceramic.

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

[0013] An ultra-high temperature thermal rectifier plate includes an upper plate, a lower plate, and an ultra-high temperature thermal rectifier structure, wherein the upper plate and the lower plate clamp the ultra-high temperature thermal rectifier structure.

[0014] A 3D printing method for an ultra-high temperature thermal rectification structure, comprising the following steps:

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

[0016] S2, prepare silica ceramic printing paste;

[0017] S3, to perform 3D printing, first import the printing model data into the software designed with the printer, slice the model, level it, and then start printing;

[0018] S4. After printing, the printed blank is sintered by heating and holding in a cycle until a multi-layered gradient minimal curved surface hollow structure is obtained.

[0019] Preferably, in step 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] The beneficial effects of this invention compared to the prior art are:

[0021] 1. This invention utilizes the initial unit cell A of the gradient minimum surface and the removed unit cell B of the gradient minimum surface to achieve the ultra-high temperature thermal rectification effect. i Boolean operations are performed to obtain a multi-layered gradient minimal curved hollow structure. Under high-temperature heat transfer conditions, the radiative heat transfer inside this structure and the heat conduction of the gradient structure generate asymmetric coupling, resulting in a highly efficient thermal rectification phenomenon. This structure can achieve thermal rectification at temperatures up to 2000℃, and it can be designed as a large-area plate with a fixed normal dimension to meet the requirements of thermal rectification regions of any area.

[0022] 2. The ultra-high temperature thermal rectification structure of this invention uses silicon oxide ceramic as the heat-resistant material. The combination of silicon oxide ceramic material and multilayer minimal curved hollow structure can greatly enhance the radiative 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. By periodically designing multi-layer gradient minimal curved hollow structures, large-size thermal rectifier flat plates can be constructed, which not only provide efficient thermal rectification effects, but also provide excellent mechanical properties and structural stability. Attached Figure Description

[0024] The accompanying drawings, which form part of this application, are provided to further illustrate the invention.

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

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

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

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

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

[0030] Figure 6 This is a schematic diagram of the structure of an ultra-high temperature thermal rectifier plate. Detailed Implementation

[0031] The invention will be described in detail below with reference to specific embodiments.

[0032] Thermal rectification devices are mainly made of nonlinear materials and phase change materials, or are realized by means 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 can withstand high temperatures in reality, especially in environments above 1000 degrees Celsius. It is difficult to find materials that can withstand high temperatures and exhibit sufficiently strong nonlinear thermal conductivity, which seriously limits the development of ultra-high temperature thermal rectification technology. (2) Thermal convection effect requires the liquid to be sealed in a closed space and the liquid to flow using mechanical devices. However, under ultra-high temperature conditions, 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 dimension of the working plane was fixed, the in-plane dimension of the rectification unit was limited. For large areas with rectification requirements, thermal rectification can only be achieved by arranging multiple units. However, the imperfect contact between the units will inevitably affect the overall thermal rectification effect.

[0033] To solve the above technical problems, see [link to relevant documentation]. Figures 1 to 5 This application provides an ultra-high temperature thermal rectification structure that can achieve thermal rectification at temperatures up to 2000℃. Furthermore, this structure can be designed as a large-area plate with a fixed normal dimension, satisfying the requirement for thermal rectification areas of any size. The ultra-high temperature thermal rectification structure is a multi-layered gradient minimum surface hollow structure. The initial unit cell of the gradient minimum surface used to achieve the ultra-high temperature thermal rectification effect is denoted as initial unit cell A, and the gradient minimum surface unit cell that needs to be removed from initial unit cell A is denoted as removal unit cell B. i i = 1, 2, ..., k, where k is the number of units B to be removed. i The number; initial cell A and removed cell B i Generate two basic structures of the same type but with different parameters. Compare the initial unit cell A with the removed unit cell B. i Boolean operations yield a multi-layered gradient minimum surface hollow structure; due to the initial unit cell A and the removed unit cell B... iBoth are gradient minimum surface structures. After performing a Boolean operation on both, the resulting structure is also a gradient minimum surface structure, with multiple layers of gradient minimum surface cavities formed inside the initial unit cell A. Under high-temperature heat transfer conditions, the radiative heat transfer inside this structure and the heat conduction of the gradient structure generate asymmetric coupling, resulting in a highly efficient thermal rectification phenomenon. The number of minimum surface cavity layers is related to the removal of unit cell B. i The quantity is related, such as Figures 1 to 5 As shown, when i=1, that is, when the unit cell is removed to one, the number of layers of the minimum surface cavity is 1, forming a two-layer gradient minimum surface hollow structure; when i=2, the number of layers of the minimum surface cavity is 2, forming a three-layer gradient minimum 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 (relative density gradation of the unit cell material when air is used as a reference substance) 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; Figures 1 to 3 Taking initial cell A as an example, in all three figures, the initial cell A represents a decrease in volume fraction from 90% to 20% from bottom to top. However, because the height of initial cell A differs in the three figures, the volume fraction decreases linearly with increasing height, and the volume fraction only needs to reach 20% from 90%. The removal of cell B... i For a minimal surface unit cell with a linearly increasing volume fraction from bottom to top, remove 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 unit cell B in i For example, in the three attached figures, the removed unit cell Bi represents a unit cell whose volume fraction increases from 5% to 10% from bottom to top. However, since the height of the removed unit cell Bi differs in the three figures, the volume fraction increases linearly with increasing height, and the volume fraction only needs to reach 10% from 5%. Because Boolean operations need to be performed on the initial unit cell A and the removed unit cell Bi to form multiple cavities within the resulting minimal surface structure and a gradient in the overall volume fraction along the height direction, 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] Among them, the initial cell A and the removed cell Bi It is one of the following minimal curved surfaces: IWP type, Gyroid type, Primitive type, Diamond type, and S type. To ensure 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, with a thermal conductivity of 0.9–1.4 W / (m·K). To achieve thermal rectification under ultra-high temperature conditions, not only must the structure's functionality be satisfied, but the material's heat resistance must also be met. Therefore, we chose ceramic material as the heat-resistant material. Considering the coupling effect of thermal conductivity and radiative heat transfer, in practical operation, we selected silicon oxide ceramic with a thermal conductivity of 0.9–1.4 W / (m·K) as the heat-resistant material. The combination of silicon oxide ceramic material and multilayer minimal curved hollow structure can greatly enhance the radiative heat transfer effect inside the structure at ultra-high temperatures. After coupling with gradient thermal conductivity, an asymmetric heat transfer effect will be generated, meaning that the heat transferred by the structure in two opposite directions is different.

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

[0038] A 3D printing method for an ultra-high temperature thermal rectification structure, comprising the following steps:

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

[0040] S2, prepare silica ceramic printing paste;

[0041] S3, to perform 3D printing, first import the printing model data into the software designed with the printer, slice the model, level it, and then start printing;

[0042] S4. After printing, the printed blank is sintered by heating and holding in a cycle until a multi-layered gradient minimal curved surface hollow structure is obtained. During the sintering process, the heating rate is 0.5-2℃ / min, the holding 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 solutions created by the present invention, and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions created by the present invention without departing from the essence and scope of the technical solutions created by the present invention.

Claims

1. A high-temperature thermal rectification structure, characterized in that: It is a multi-layered gradient minimum surface hollow structure. The initial unit cell of the gradient minimum surface used to achieve the ultra-high temperature thermal rectification effect is denoted as the initial unit cell A, and the gradient minimum surface unit cell that needs to be removed in the initial unit cell A is denoted as the removal unit cell B. i , i =1,2,……,k, where k is the number of units B removed. i The number; the initial unit A and the removed unit B i Boolean operations yield a multi-layered gradient minimum surface hollow structure; Initial cell A and removed cell B i Generate two basic structures of the same type but with different parameters; The initial unit cell A is a minimal surface unit cell with a volume fraction that decreases 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 unit cell B... i For a minimal surface unit cell with a linearly increasing volume fraction from bottom to top, remove unit cell B. i The volume fraction from bottom to top is M i To N i gradient, N i Greater than M i ; >0, >0, ( )-( ) > 0, M i >M i+1 N i >N i+1 .

2. 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 the following minimal surfaces: IWP type, Gyroid type, Primitive type, Diamond type, and S-type.

3. The ultra-high temperature thermal rectification structure according to claim 2, characterized in that: The initial cell A and the removed cell Bi are of the Gyroid type.

4. 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.

5. The ultra-high temperature thermal rectification structure according to claim 4, characterized in that: The ultra-high temperature thermal rectification structure is made of silicon oxide ceramic.

6. The ultra-high temperature thermal rectification structure according to claim 5, characterized in that: The thermal conductivity of the silicon oxide ceramic is 0.9~1.4 W / (m•K).

7. A high-temperature thermal rectifier plate, characterized in that: It includes an upper plate, a lower plate, and an ultra-high temperature thermal rectifier structure as described in any one of claims 1 to 6, wherein the upper plate and the lower plate clamp the ultra-high temperature thermal rectifier structure.

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