Thermal current regulation device based on near-field thermal radiation

Abstract

The present invention discloses a heat flux regulation device based on near-field thermal radiation. The heat flux regulation device includes a first radiator and a second radiator arranged oppositely, the distance between the first radiator and the second radiator is d. The first radiator is a composite metamaterial, and the second radiator is a polar material. The first radiator includes a substrate and nanoparticles mixed and distributed in the substrate. By utilizing the inherent nonlocal effect of materials in a small volume, the present invention can achieve an efficient thermal diode under a small temperature difference. At the same time, by utilizing the characteristics of the multi-parameter tunability of the composite metamaterial, a high-degree-of-freedom thermal diode with the working temperature and the working temperature range being controllable to a certain extent by humans is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of heat flux regulation, and particularly relates to a heat flux regulation device based on near-field thermal radiation. Background Art

[0002] Heat is one of the most fundamental forms of energy in nature, and effective control of the heat transfer process is an important challenge faced by modern technologies. By flexibly regulating the heat flux, not only can an efficient energy conversion system be realized to heat and cool objects more effectively, but also the use of phonons for computing and storing data can be achieved.

[0003] Among the three basic ways of heat flux transfer, the control of heat transfer is mainly based on the control of heat conduction and thermal radiation. Among them, the control of heat conduction is often limited by the inherent Kapitza thermal resistance of the object; while thermal radiation has two aspects, far-field and near-field. For far-field thermal radiation, it is restricted by the blackbody radiation law. For the regulation of heat conduction and far-field thermal radiation, it mostly relies on static or passive thermal elements, which is very scarce compared with highly nonlinear, active and adjustable electronic components. However, the research and utilization of near-field thermal radiation have broken the above limitations, making thermal elements and electronic components somewhat comparable, and even promising to provide some new functions that electronic components do not have.

[0004] Near-field thermal radiation means that when the distance between radiators is less than the thermal characteristic wavelength, the classical blackbody radiation law is broken, and the evanescent wave thermally excited by the object itself dominates the radiative heat transfer. For two radiators that are very close to each other, their radiative heat flux is affected by the electromagnetic properties of their respective materials. Also, due to the near-field coupling effect, while greatly enhancing the radiative heat transfer, the corresponding device has extremely high nonlinearity and controllability.

[0005] Currently, heat flux regulation devices based on near-field thermal radiation have been widely studied and applied in various thermal devices such as thermal diodes, thermal logic gates, and thermal shunts. Among them, the thermal diode is a very basic heat flux regulation device. Its function is similar to that of a diode in the electrical field. An ideal thermal diode can achieve unidirectional conduction and reverse blocking of the heat flux. For an actual thermal diode, when the temperature difference is fixed, swapping the temperatures of the two radiators requires that the heat flux under forward bias is much greater than that under reverse bias. Therefore, the performance of a thermal diode can be measured by the rectification efficiency, which is defined as the ratio of the difference between the forward and reverse heat fluxes to the forward heat flux. The maximum value of this ratio is 1, representing an ideal thermal diode.

[0006] The performance of a thermal diode depends on the variation of the electromagnetic properties of two radiators with temperature. Compared with natural materials, metamaterials can enhance the influence of temperature variation on the properties of radiators through design, thereby improving the rectification efficiency of the system. Metamaterials refer to artificial materials designed by humans that can utilize conventional materials and special structures to achieve extraordinary optoelectronic properties. Composite metamaterials are a typical classification of metamaterials, which are usually composed of two or more materials with different physical properties mixed in the required shape and proportion. Compared with other types of metamaterials, composite materials are simpler in design and easier to produce, and have been widely used in military, industrial, and daily life fields. Due to the highly adjustable properties of composite metamaterials and other types of metamaterials, they have received great attention in the application fields of near-field thermal radiation such as thermal diodes in recent years.

[0007] The working wavelength of metamaterials applied in the field of near-field thermal radiation is usually several hundred to several thousand nanometers, which requires the structural unit to be a dozen nanometers or even a few nanometers. At such scales, the nonlocal effects of nanostructures or nanoparticles must be considered. Nonlocality or spatial dispersion means that the dielectric function (or permeability) of a material is related to the frequency and wave vector of the incident light, while for the classical local case, these quantities are only related to the incident frequency. Compared with the calculation of the local model, the resonance frequency of the material predicted by the nonlocal model will undergo a blue shift and the near-field enhancement will be significantly reduced. However, through reasonable design, the nonlocal effect is not necessarily harmful to the application of near-field thermal radiation.

[0008] Therefore, in view of the above technical problems, it is necessary to provide a heat flux regulation device based on near-field thermal radiation. Summary of the Invention

[0009] The object of the present invention is to provide a heat flux regulation device based on near-field thermal radiation.

[0010] In order to achieve the above object, the technical solution provided by an embodiment of the present invention is as follows:

[0011] A heat flux regulation device based on near-field thermal radiation, the heat flux regulation device includes a first radiator and a second radiator arranged opposite to each other, the distance between the first radiator and the second radiator is d, the first radiator is a composite metamaterial, the second radiator is a polar material, and the first radiator includes a substrate and nanoparticles mixed and distributed in the substrate.

[0012] In one embodiment, the size of the nanoparticles is 25nm to 150nm; and / or,

[0013] The volume fraction of the nanoparticles is 1% to 10%; and / or,

[0014] The nanoparticles are any one or a combination of spherical, ellipsoidal, and cylindrical shapes; and / or,

[0015] The nanoparticles are distributed in the substrate in an ordered or disordered manner.

[0016] In one embodiment, the nanoparticles are semiconductor material nanoparticles with obvious non-local effects and properties that change with temperature, and the nanoparticles are one or more of indium antimonide nanoparticles and gallium arsenide nanoparticles.

[0017] In one embodiment, the substrate is a non-metallic material, and the non-metallic material includes any one of air, water, oil, glass, resin, and rubber.

[0018] In one embodiment, the polar material is any one of 3C-silicon carbide, 6H-silicon carbide, cubic boron nitride, hexagonal boron nitride, silicon dioxide, aluminum oxide, zinc sulfide, zinc selenide, magnesium oxide, and gallium nitride.

[0019] In one embodiment, the distance between the first radiator and the second radiator is 30 nm to 1000 nm; and / or,

[0020] the thickness of the first radiator is 500 nm to 1000 nm; and / or,

[0021] the thickness of the second radiator is 500 nm to 1000 nm.

[0022] In one embodiment, the heat flux regulation device is a near-field thermal diode;

[0023] When the first radiator is at a high temperature and the second radiator is at a low temperature, the near-field thermal diode is in a forward-biased state, and a large amount of forward heat flux flows from the first radiator to the second radiator;

[0024] When the first radiator is at a low temperature and the second radiator is at a high temperature, the near-field thermal diode is in a reverse-biased state, and a very small amount of reverse heat flux flows from the second radiator to the first radiator.

[0025] In one embodiment, the effective dielectric function of the first radiator is:

[0026]

[0027] where,

[0028] Y = P·[k s a.y1(k s a)]′ε T -y1(k s a)ε s ;

[0029] J = P·[k s a.j1(k sa)]′ε T -j1(k s a)ε s ;

[0030]

[0031] ε T and ε L are the transverse and longitudinal dielectric functions of the nanoparticle material, ε ∞ is the relative dielectric constant of the nanoparticle material at high frequencies, ε G is the relative dielectric constant of the substrate material, a is the radius of the nanoparticle, and the functions j n 、h n and y n are the spherical Bessel function of the first kind, the spherical Hankel function of the first kind, and the spherical Bessel function of the second kind, respectively.

[0032] In one embodiment, the radiative heat flux between the first radiator and the second radiator is:

[0033]

[0034] where Q f is the larger forward heat flux, Q r is the smaller reverse heat flux, Θ(ω,T) is the average energy of the Planck oscillator at temperature T, T H and T L are the temperatures of the high temperature and the low temperature, respectively, k ρ is the transverse wave vector of the electromagnetic wave, d is the distance between the first radiator and the second radiator, and τ α (ω,k ρ ,d) is the energy transfer coefficient of the electromagnetic wave at different polarizations.

[0035] In one embodiment, the rectification efficiency of the near-field thermal diode is:

[0036]

[0037] where Q f is the larger forward heat flux, Q r is the smaller reverse heat flux.

[0038] Compared with the prior art, the present invention has the following advantages:

[0039] The present invention utilizes the inherent nonlocal effect of materials in a small volume to achieve an efficient thermal diode at a small temperature difference; at the same time, by utilizing the characteristics of the multi-parameter tunability of the composite metamaterial, a high-degree-of-freedom thermal diode with controllable operating temperature and operating temperature range to a certain extent is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0041] Figure 1 Structural schematic diagram of the composite metamaterial in the present invention;

[0042] Figure 2 Structural schematic diagram of the heat flux regulation device (near-field thermal diode) in the present invention;

[0043] Figure 3 Schematic diagram showing the variation of the dielectric function of a composite metamaterial in the present invention with the radius and temperature of the nanoparticles;

[0044] Figure 4 Radiative heat exchange coefficient diagram of the near-field thermal diode in the forward and reverse temperature biases in Embodiment 1 of the present invention;

[0045] Figure 5 Diagram showing the variation of the rectification efficiency of the near-field thermal diode in Embodiment 1 of the present invention with the temperature difference and distance between two radiators when the volume fraction ratio of the composite metamaterial is different. Detailed implementation manners

[0046] The present invention will be described in detail below in conjunction with the various implementation manners shown in the accompanying drawings. However, these implementation manners do not limit the present invention, and any structural, method, or functional transformation made by those of ordinary skill in the art based on these implementation manners is included in the protection scope of the present invention.

[0047] In near-field thermal radiation, mainly three different electromagnetic modes participate in the heat transport: the propagating mode, the evanescent mode, and the surface mode. Among them, the surface mode has extremely high locality, that is, this type of mode can only exist in a very narrow frequency range, so as to achieve near-single-channel enhancement of near-field heat flux transmission in the forward bias (when the mode coupling occurs), and suppression of near-field heat flux transmission in the reverse bias (when the mode decoupling occurs). The present invention is based on a composite metamaterial supporting the local surface plasmon mode and a polar material supporting the surface phonon polariton mode to achieve a high-performance near-field thermal diode.

[0048] Furthermore, the present invention is based on the inherent non-local effect of materials in a small volume, and makes full use of the blue shift effect of the resonance frequency and local surface mode frequency of the materials caused by this effect to achieve an efficient thermal diode under a small temperature difference. This near-field thermal diode can achieve a multi-degree-of-freedom near-field thermal diode by adjusting parameters such as the particle size and volume fraction ratio in the composite material.

[0049] Furthermore, the present invention also matches the polar materials in another radiator, and utilizes the different frequencies of the electromagnetic modes supported by different polar materials, so as to change the temperature when the electromagnetic modes supported by the two radiators are coupled, and realizes that the operating temperature and the operating temperature range of the thermal diode can be artificially selected and controlled to a certain extent.

[0050] In the present invention, the key to achieving high-efficiency heat flux rectification efficiency lies in the composite metamaterial made of semiconductor material nanoparticles. The particle shape in the composite metamaterial can be any one or a combination of spherical, ellipsoidal, and cylindrical shapes, such as Figure 1 Shown is a schematic diagram of different types of composite metamaterial structures adopted by the present invention, and the nanoparticle distribution can be ordered or disordered.

[0051] Refer Figure 2 As shown, the heat flux regulation device based on near-field thermal radiation in the present invention includes a first radiator 10 and a second radiator 20 arranged oppositely. The distance between the first radiator 10 and the second radiator 20 is d. The first radiator is a composite metamaterial, and the second radiator is a polar material. The first radiator includes a substrate 11 and nanoparticles 12 mixedly distributed in the substrate.

[0052] The heat flux regulation device in the present invention is a near-field thermal diode, wherein:

[0053] When the first radiator is at a high temperature and the second radiator is at a low temperature, the near-field thermal diode is in a forward bias state, and a large amount of forward heat flux flows from the first radiator to the second radiator;

[0054] When the first radiator is at a low temperature and the second radiator is at a high temperature, the near-field thermal diode is in a reverse bias state, and an extremely small amount of reverse heat flux flows from the second radiator to the first radiator.

[0055] Preferably, the thicknesses of the first radiator and the second radiator are 500 nm to 5000 nm. Further, it can be 500 nm to 1000 nm, such as 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, etc. For related applications in the field of near-field thermal radiation, materials with a thickness greater than 500 nm can be regarded as semi-infinite thick materials, and the actual thickness of the materials hardly affects the near-field heat flux and the rectification efficiency of the near-field thermal diode.

[0056] The first radiator in the present invention is a composite metamaterial, and the composite metamaterial is a fine-grained composite material with spherical uniform mixing, which is made by mixing hard nanoparticles in a substrate.

[0057] The nanoparticles in the present invention are semiconductor material nanoparticles with obvious non-local effects and properties that change with temperature, such as indium antimonide (InSb), gallium arsenide (GaAs), or any one of them.

[0058] The size (radius) of the nanoparticles in the present invention is 10 nm to 250 nm. Further, it can be 25 nm - 150 nm, such as 25 nm, 50 nm, 75 nm, 100 nm, 125 nm, 150 nm, etc.

[0059] Achieving an efficient near-field thermal diode depends on the non-local effect of materials at small sizes. For the semiconductor material nanoparticles in the present invention, when their particle radius is greater than 150 nm, the frequency blue-shift effect caused by non-locality becomes very weak. Therefore, in an alternative technical solution, the radius of the spherical particles is below 250 nm. On the other hand, when the investigated particle radius is too small, quantum effects have to be considered. To avoid such situations, the radius of the semiconductor nanoparticles in this embodiment is above 25 nm.

[0060] The volume fraction of the nanoparticles in the composite metamaterial of the present invention is 0.1% - 30%. Further, it can be 1% - 10%, such as 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc.

[0061] The substrate of the composite metamaterial in the present invention is a common non-metallic material that can be used as a substrate, such as air, water, oil, glass, resin, rubber, etc.

[0062] The second radiator in the present invention is a piece of polar material, which can be selected from any one of 3C-silicon carbide (3C-SiC), 6H-silicon carbide (6H-SiC), cubic boron nitride (cBN), hexagonal boron nitride (hBN), silicon dioxide (SiO2), aluminum oxide (Al2O3), zinc sulfide (ZnS), zinc selenide (ZnSe), magnesium oxide (MgO), gallium nitride (GaN), etc. Preferably, the polar material is selected from one of 3C-silicon carbide (3C-SiC), cubic boron nitride (cBN), and silicon dioxide (SiO2).

[0063] The distance between the first radiator and the second radiator in the present invention is 30 nm to 1000 mm, such as 30 nm, 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, etc.

[0064] In the present invention, achieving the thermal rectification effect of the near-field thermal diode mainly relies on the coupling and decoupling of the local surface plasmon mode supported by the first radiator and the surface phonon polariton mode supported by the second radiator. Since the intensity of the surface mode decays exponentially with the increase of the distance between the two radiators, when the distance between the radiators is large, the rectification efficiency of the near-field thermal diode based on surface mode coupling will also decrease significantly. According to the present invention, when the distance between the two radiators is 1000 nm, the near-field thermal diode still has a certain rectification effect. Therefore, in an alternative technical solution, the distance between the two radiators is less than 1000 nm.

[0065] In the calculation, first, the dielectric properties of the composite metamaterial made of nanoparticles mixed in a substrate need to be equivalently processed. When the nanoparticles are very small, the nonlocal effect needs to be considered, that is, the influence of the wave vector on the dielectric function of the material needs to be investigated. For the composite metamaterial, to calculate its effective dielectric function, it is necessary to know the longitudinal wave vector k of the electromagnetic wave in the nonlocal semiconductor nanoparticles L , the transverse wave vector k T , and the transverse wave vector k in the substrate s . Further, the effective dielectric function of the composite metamaterial is calculated using the nonlocal effective medium theory:

[0066]

[0067] where

[0068] Y = P·[k s a.y1(k s a)]′ε T -y1(k s a)ε s ;

[0069] J = P·[k s a.j1(k s a)]′ε T -j1(k s a)ε s ;

[0070]

[0071] ε T and ε L are the transverse and longitudinal dielectric functions of the nanoparticle material, ε ∞ is the relative dielectric constant of the nanoparticle material at high frequencies, ε S is the relative dielectric constant of the substrate material, a is the radius of the nanoparticle, and the functions j n , h n and y nThey are the spherical Bessel function of the first kind, the spherical Hankel function of the first kind, and the spherical Bessel function of the second kind respectively.

[0072] Figure 3 The schematic diagram of the dielectric function of the composite metamaterial varying with the radius and temperature of the nanoparticles is shown. The effective dielectric function of the composite metamaterial, the real part Re(ε eff ) always shows a wavy line shape, while the imaginary part Im(ε eff ) has a resonance peak. When the radius of the nanoparticles in the composite metamaterial is smaller, the non-local effect is more obvious, the blue-shift effect of the resonance peak is more obvious, and the value of the resonance peak is also smaller. Temperature also affects the effective dielectric function of the composite metamaterial. When the temperature is higher, the blue-shift effect of the effective dielectric function of the composite metamaterial is more obvious, but the values of its real part and imaginary part will be larger.

[0073] Based on the theory of fluctuating electrodynamics, the radiative heat flux between two semi-infinite parallel planes (i.e., between the first radiator and the second radiator) is:

[0074]

[0075] where Q f is the larger forward heat flux, Q r is the smaller reverse heat flux, Θ(ω, T) is the average energy of the Planck oscillator at temperature T, T H and T L are the temperatures of high temperature and low temperature respectively, k ρ is the transverse wave vector of the electromagnetic wave, d is the distance between the first radiator and the second radiator, τ α (ω, k ρ , d) is the energy transfer coefficient of the electromagnetic wave in different polarizations. This coefficient is related to the dielectric functions of the two radiators and reflects the coupling degree of various modes on the two radiators.

[0076] After calculating the forward and reverse heat fluxes under different temperature biases, the core performance parameter of the near-field thermal diode - the rectification efficiency η can be further calculated. Its definition is the ratio of the difference between the forward and reverse heat fluxes to the larger reverse heat flux, that is:

[0077]

[0078] where Q f is the larger forward heat flux, Q r is the smaller reverse heat flux.

[0079] When the rectification efficiency η is maximum at 1, it represents an ideal near-field thermal diode. When it is minimum at 0, it represents a situation where there is no rectification effect at all.

[0080] The present invention will be further described below in conjunction with specific embodiments.

[0081] Example 1:

[0082] In this example, indium antimonide (InSb) is selected as the semiconductor material nanoparticles in the composite metamaterial, and silicon dioxide (SiO2) is selected as the polar material of the second radiator. The working temperature of this example is 425K at high temperature and 300K at low temperature, with a temperature difference of 125K. Both the composite metamaterial layer and the polar material layer are semi-infinite flat plates, and the distance between them is 30nm. As Figure 4 shown, the composite metamaterial layer is a spherical fine-grained composite structure. Indium antimonide spherical nanoparticles with a radius of 25nm are uniformly dispersed in a substrate with a relative permittivity approximately equal to 1 at a volume fraction ratio of 10%. The finally calculated rectification efficiency η is 92%.

[0083] Figure 4 The figure shows the radiative heat exchange coefficient diagrams corresponding to the forward and reverse temperature biases in this example. The x-axis in the figure is the angular frequency, and the y-axis in the figure is the normalized transverse wave vector. When k ρ c / ω < 1, it represents that the electromagnetic wave is in the transmission mode. When k ρ c / v > 1, it is the evanescent mode.

[0084] Figure 4 The points in represent the energy transmission channels at specific frequencies and transverse wave vectors. The brighter the point, the stronger the energy transmission ability of the channel. When the composite metamaterial layer of the first radiator is at a high temperature T H = 425K and the polar material layer of the second radiator is at a low temperature T L = 300K, the near-field thermal diode is in the forward bias condition. The radiative heat exchange coefficient diagram shows nearly single-frequency channel energy transmission near the angular frequency of 0.9×10 14 rad s -1 . This is exactly because the local surface plasmon mode supported by the composite metamaterial couples with the surface phonon polarization mode supported by the polar material. When the composite metamaterial layer is at a low temperature T L = 300K and the polar material layer is at a high temperature T H = 425K, the near-field thermal diode is in the reverse bias condition. At this time, the radiative heat exchange coefficient diagram shows weak energy transmission channels almost only in the range of k ρ c / ω < 1. At the same time, Figure 4 the two surface modes are very far apart, and the surface modes are decoupled, indicating that the weak heat flow in the reverse bias is due to the propagation mode.

[0085] Figure 5 The figure shows the rectification efficiency as a function of the temperature difference between the two radiators (low temperature T LFixed at 300K, high temperature T H (change), change in spacing. It can be seen that when the volume fraction is relatively large, this embodiment can maintain a good thermal rectification effect (η > 50%) within a large temperature difference range and a large spacing range.

[0086] Embodiment 2:

[0087] In the composite metamaterial of this embodiment, the radius of the nanoparticles is taken as 250 nm, and the working temperature is set as high temperature T H = 625K, low temperature T L = 300K, the temperature difference is 325K, and the other parameters are the same as those in Embodiment 1. The calculated thermal rectification efficiency is 94%. The rectification efficiency of this embodiment is slightly higher than that of Embodiment 1, but the required temperature difference is much larger than that of Embodiment 1.

[0088] Embodiment 3:

[0089] The polar material selected in this embodiment is cubic boron nitride (cBN), and the working temperature is set as high temperature T H = 600K, low temperature T L = 400K, the temperature difference is 200K, and the other parameters are the same as those in Embodiment 1. The calculated thermal rectification efficiency is 94%. By matching and selecting different semiconductor materials and polar materials, the working temperature and the working temperature range of the near-field thermal diode can be selected to a certain extent.

[0090] The near-field thermal diode and its application designed based on polar materials and composite metamaterials proposed by the present invention mainly utilize the coupling and decoupling of modes between two radiators. This is mainly because the properties of the selected polar material hardly change with temperature within the investigated temperature range, so the frequency of its surface electromagnetic resonance mode is fixed, while the properties of the designed composite metamaterial are affected by temperature. When in the forward bias, the local surface plasmon supported by the composite metamaterial couples with the surface phonon polarization supported by the polar material, resulting in a large forward heat flux. When in the reverse bias, their resonance modes no longer couple, resulting in a small reverse heat flux.

[0091] From the above technical solutions, it can be seen that the present invention has the following beneficial effects:

[0092] The present invention utilizes the inherent nonlocal effect of materials in a small volume to achieve an efficient thermal diode under a small temperature difference; at the same time, by using the characteristics of the composite metamaterial with adjustable multiple parameters, a high-degree-of-freedom thermal diode with the working temperature and the working temperature range that can be artificially controlled to a certain extent is realized.

[0093] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be construed as limiting the claims involved.

[0094] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A heat flux control device based on near-field thermal radiation, characterized in that, The heat flux regulation device includes a first radiator and a second radiator which are oppositely arranged, and the distance between the first radiator and the second radiator is , the first radiator is a composite metamaterial, the second radiator is a polar material, the first radiator includes a substrate and nanoparticles mixed and distributed in the substrate, the nanoparticles are semiconductor material nanoparticles with obvious non-local effects and properties that change with temperature, the nanoparticles are one or more of indium antimonide nanoparticles and gallium arsenide nanoparticles, the size of the nanoparticles is 25nm to 150nm, the thickness of the first radiator is 500nm to 1000nm, and the thickness of the second radiator is 500nm to 1000nm.

2. The heat flux regulation device based on near-field thermal radiation according to claim 1, wherein the volume fraction of the nanoparticles is 1% to 10%; and / or, the nanoparticles are any one or a combination of spherical, ellipsoidal, and cylindrical shapes; and / or, the nanoparticles are distributed in the substrate in an ordered or disordered manner.

3. The heat flux regulation device based on near-field thermal radiation according to claim 1, wherein The substrate is a non-metallic material, and the non-metallic material includes any one of air, water, oil, glass, resin, and rubber.

4. The heat flux regulation device based on near-field thermal radiation according to claim 1, characterized in that The polar material is any one of 3C-silicon carbide, 6H-silicon carbide, cubic boron nitride, hexagonal boron nitride, silicon dioxide, aluminum oxide, zinc sulfide, zinc selenide, magnesium oxide, and gallium nitride.

5. The heat flux regulation device based on near-field thermal radiation according to claim 1, wherein The distance between the first radiator and the second radiator is 30 nm to 1000 nm.

6. The heat flux regulation device based on near-field thermal radiation according to claim 1, characterized in that, The heat flux regulation device is a near-field thermal diode; when the first radiator is at a high temperature and the second radiator is at a low temperature, the near-field thermal diode is in a forward-biased state, and a large amount of forward heat flux flows from the first radiator to the second radiator; when the first radiator is at a low temperature and the second radiator is at a high temperature, the near-field thermal diode is in a reverse-biased state, and a very small amount of reverse heat flux flows from the second radiator to the first radiator.

7. The heat flux regulation device based on near-field thermal radiation according to claim 6, wherein The effective dielectric function of the first radiator is: ； wherein, ； ； ； and are the transverse and longitudinal dielectric functions of the nanoparticle material, is the relative dielectric constant of the nanoparticle material at high frequencies, is the relative dielectric constant of the substrate material, is the radius of the nanoparticle, and the functions 、 and are the spherical Bessel function of the first kind, the spherical Hankel function of the first kind, and the spherical Bessel function of the second kind, respectively.

8. The heat flux regulation device based on near-field thermal radiation according to claim 6, wherein the radiative heat flux between the first radiator and the second radiator is: ； Among them, is a larger positive heat flux, is a smaller negative heat flux, is the average energy of the Planck oscillator at temperature ; and are the temperatures of the high temperature and the low temperature respectively, is the transverse wave vector of the electromagnetic wave, is the distance between the first radiator and the second radiator, is the energy transfer coefficient of the electromagnetic wave in different polarizations.

9. The heat flux regulation device based on near-field thermal radiation according to claim 8, wherein the rectification efficiency of the near-field thermal diode is: ； is a larger positive heat flow, is a smaller negative heat flow.

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