Near-field radiative heat transfer system filled with artificial double-negative metamaterials

Abstract

The present application relates to a near-field radiation heat transfer system filled with artificial hyperbolic metamaterials. The system comprises an emitter, a receiver and a filling medium, the filling medium is arranged between the emitter and the receiver; the filling medium is provided with artificial hyperbolic metamaterials, the artificial hyperbolic metamaterials are potassium permeated silicon dioxide nano-porous matrix filling materials; wherein, the system adopts a full-coupling multi-physical field framework integrating near-field radiation, conduction transmission and nonlinear temperature stratification. The present application adopts potassium permeated silicon dioxide nano-porous matrix filling materials as hyperbolic low-loss gap filling medium, and establishes a full-coupling multi-physical field framework integrating near-field radiation, conduction transmission and nonlinear temperature stratification, and realizes near-field radiation dominated heat transfer in a solid-state system and exceeds the conduction heat flow.

Description

Technical Field

[0001] This invention relates to a near-field radiation heat transfer system filled with artificial hyperbolic metamaterials, belonging to the field of thermophotonics. Background Technology

[0002] Near-field radiative heat transfer (NFRHT) utilizes the evanescent wave tunneling effect over subwavelength distances to achieve heat flux density exceeding the blackbody limit by several orders of magnitude through resonant excitation. In metals and polar materials, surface plasmon / phonon polariton (SPP / SPhP) coupling across a vacuum gap is fundamental to enhanced heat flux, while metamaterial structures such as nanogratings, pores, and multilayer films can further excite additional resonant modes such as magnetic polaritons and guided wave modes. Among these, hyperbolic modes can support the propagation of high-frequency vector waves. Existing research shows that broadband excitation of hyperbolic phonon polaritons can significantly enhance near-field radiative heat transfer by exciting hyperbolic phonon polaritons and surface phonon polaritons, thereby improving near-field radiative heat transfer. Furthermore, the main measurement strategies for near-field radiative heat transfer between plates include using nanoparticle / cylindrical spacers, substrate-embedded nanogap structures, or precision displacement systems. A landmark achievement was the first breakthrough of the blackbody limit using glass plates separated by nanoparticles, achieved through microelectromechanical systems (MEMS) technology in silicon carbide (SiC) nanobeams, creating a 100 nm gap. Subsequently, high-precision displacement control techniques have reduced the vacuum gap to below 100 nm, even down to 10 nm, improving near-field radiative heat transfer by three to four orders of magnitude compared to the blackbody limit. However, although sub-100 nm vacuum gaps can achieve extremely high heat flux densities exceeding 10 W / cm², the absolute radiative power in current experiments remains limited to approximately 1.5 mW. This is because when the gap is smaller than 100 nm, the effective heat transfer area is limited to the micrometer scale (approximately 0.01 mm²), resulting in a total radiative power far lower than the conductive heat power of ordinary solid materials at the same temperature difference, even with extremely high heat flux densities.

[0003] To address the fundamental contradiction between controlling nano-gap and expanding heat transfer area in near-field radiative heat transfer, filling vacuum gaps with bulk media has become a revolutionary strategy. Existing techniques propose filling vacuum gaps with a 10 cm thick high-refractive-index gallium arsenide (GaAs) layer to construct a super-Planck thermophotovoltaic model; utilizing the low energy dissipation characteristics of hyperbolic waveguides, a three-body configuration is proposed to achieve long-distance near-field heat flow; and theoretical methods for near-field radiative heat transfer in multi-body systems are also proposed. Furthermore, existing techniques have calculated near-field radiative heat transfer in single-layer or multi-layer hexagonal boron nitride (hBN) media, finding that it accounts for 27% of total heat transfer at 600 K, comparable to conduction heat transfer. Despite the progress in theoretical research on gap-filled near-field radiative heat transfer systems, practical applications still face fundamental limitations: for example, existing studies often use ideal materials or natural hyperbolic crystals (such as orientation-dependent hBN) with dielectric constant assumptions, restricting experimental feasibility and scalability; existing models fail to fully consider the multi-physics coupling of radiation and heat conduction within the filled medium, neglecting nonlinear temperature distribution and self-emission contributions, leading to significant biases in heat flow prediction. Furthermore, although the filled gap configuration can significantly increase radiative heat flux compared to the vacuum gap, no studies have reported cases where radiation-dominated heat transfer reaches or exceeds conductive heat transfer. Summary of the Invention

[0004] This invention provides a near-field radiative heat transfer system filled with artificial hyperbolic metamaterials, aiming to solve at least one of the technical problems existing in the prior art.

[0005] The technical solution of the present invention relates to a near-field radiation heat transfer system filled with artificial hyperbolic metamaterials. The system includes an emitter, a receiver, and a filling medium, wherein the filling medium is disposed between the emitter and the receiver. The filling medium is provided with artificial hyperbolic metamaterials, which are potassium-permeable silica nanoporous matrix filling materials. The system adopts a fully coupled multiphysics framework that integrates near-field radiation, conduction transport, and nonlinear temperature stratification.

[0006] Furthermore, both the emitter and the receiver are composed of doped silicon, and the silicon dioxide in the artificial hyperbolic metamaterial has uniform through-pores and is infiltrated with potassium.

[0007] Furthermore, the fully coupled multiphysics framework employs a multi-layer discretization model controlled by the principle of energy conservation to obtain the nonlinear temperature distribution generated by the coupling of radiation and conduction.

[0008] Furthermore, in the multi-layer discretization model, the filling medium includes N discrete sub-layers, each of which has a uniform temperature, and the two side boundaries of each discrete sub-layer are the transmitter and the receiver, respectively.

[0009] Each of the discrete sublayers is simultaneously subjected to conductive heat flow from the adjacent layer and cumulative radiative heat flow from all other layers.

[0010] Furthermore, the fully coupled multiphysics framework employs the dyadic Green's function method and a random current source thermal radiation model to obtain the near-field radiative heat flux of the system.

[0011] Thermal radiation satisfies the fluctuation and dissipation theorem, as follows:

[0012] ;

[0013] In the formula, Indicates position Fluctuating current source at the location, express Fluctuating current source at the location; The vacuum permittivity; an indexed tensor. Defined as ; Let be the Dirac function, which represents the locality of the real space and the frequency space; For frequency ,temperature The average energy of the lower Planck oscillator and These are the reduced Planck constant and the Boltzmann constant, respectively.

[0014] Furthermore, in the dyadic Green's function method and the stochastic current source thermal radiation model, the radiative heat flow Through calculation The ensemble-mean Poynting vector of the direction is obtained;

[0015] Wherein, the discrete sub-layer In the interface along Average spectral Poynting flux density in the direction It is expressed as follows:

[0016] ;

[0017] In the formula, Represented as frequency ,temperature The average energy of the lower Planck oscillator can be calculated using the following formula:

[0018] ;

[0019] In the formula Represents the reduced Planck constant. This represents the Boltzmann constant.

[0020] in, Here, the near-field transport factor is expressed as follows:

[0021] ;

[0022] In the formula, Area of ​​a single cell For the Levy and Civitar tensor, and For the dyadic Green's operator, the observation point electromagnetic field at the location and With the source The current correlation at the point can be obtained , ,in Indicates position Fluctuating current source at the location; For trace operators, Indicates matrix transpose. Represents a conjugate matrix;

[0023] Wherein, the discrete sub-layer Absorbed radiation can pass through its two interfaces. Difference calculation; near-field transmission factor By considering all possible in-plane wave vectors Integral transmission coefficient Obtain, where the transmission coefficient The probability of thermally excited photons propagating from the emitter layer to the receiver layer is characterized and calculated using either rigorous coupled-wave analysis (RCWA) or the scattering matrix method, depending on the structure; during integration... The upper limit is set to , is the silicon lattice constant.

[0024] Furthermore, the fully coupled multiphysics framework is filled with a potassium-infiltrated porous silica matrix material. Directional thermal conductivity Its conduction and heat transfer properties are characterized as follows:

[0025] ;

[0026] In the formula, The percentage of potassium in the silica matrix. and Thermal conductivity of nano-thickness silica film and potassium film, respectively Its thermal conductivity with bulk materials The relationship is represented as follows:

[0027] ;

[0028] In the formula, The correlation coefficient of nanostructure (nanofilm is taken as) ), , Knudsen number In the formula To fill the thickness of the medium, The mean free path of phonon transport in the material. It is expressed as follows:

[0029] ;

[0030] In the formula, For material density, Specific heat capacity (by volume) The average group velocity.

[0031] Furthermore, the fully coupled multiphysics framework employs a model of coupled heat conduction and near-field radiation heat transfer to solve for the temperature distribution within the filling medium;

[0032] The model for coupled heat conduction and near-field radiative heat transfer is expressed as follows:

[0033] ;

[0034] In the formula, Represents the discrete sublayer and Conductive heat flow at the interface Display Interface The cumulative radiative heat flow from all layers; For the discrete sub-layer and Conductive heat flow at the interface For the interface The cumulative radiative heat flux from all layers is represented as follows:

[0035] ;

[0036] ;

[0037] In the formula, and They represent the first and The temperature of the layer, This indicates the total number of layers.

[0038] Furthermore, the fully coupled multiphysics framework employs a genetic algorithm to iteratively solve for the temperature distribution of each sublayer, minimizing the objective function. It is expressed as follows:

[0039] ;

[0040] In the formula, The average heat flux across all interfaces in each iteration is expressed as follows:

[0041] .

[0042] Furthermore, when the potassium filling rate in the artificial hyperbolic metamaterial is 0.1, based on Brugmann's effective medium theory and The real and imaginary parts of the effective dielectric tensor of the artificial hyperbolic metamaterial are calculated.

[0043] The beneficial effects of this invention are as follows:

[0044] This invention employs a near-field radiative heat transfer system filled with artificial hyperbolic metamaterials. A potassium-permeable silica nanoporous matrix is ​​used as the filling medium for the hyperbolic low-loss gap, overcoming the fundamental limitations of near-field radiative heat transfer. The use of artificial hyperbolic metamaterials combines broadband hyperbolic dispersion with structural feasibility. Furthermore, this invention establishes a fully coupled multiphysics framework integrating near-field radiation, conduction, and nonlinear temperature stratification. In a solid-state system, radiation-dominated heat transfer surpasses conduction heat flow. Therefore, when the filling metamaterial thickness is 100 nm, the radiative heat flow is increased by five orders of magnitude compared to near-field radiative heat transfer in a vacuum gap; it is comparable to conduction heat flow at ΔT=100 K; and reaches five times the conduction heat flow at ΔT=1000 K. Attached Figure Description

[0045] Figure 1 This is a structural diagram of a near-field radiative heat transfer system using hyperbolic metamaterials according to the present invention.

[0046] Figure 2 This is a schematic diagram of the structure of the discretized one-dimensional multilayer model according to the present invention.

[0047] Figure 3 These are the real and imaginary parts of the effective dielectric function according to the present invention.

[0048] Figure 4 It is the K-penetration according to the present invention Nanoporous metamaterials in terms of filling ratio The ordinary component eEMT,O and the special component eETM,E.

[0049] Figure 5 This is a comparison diagram of spectral radiative heat flux between the exact RCWA solution and the EMT approximation in the calculation verification of the hierarchical framework according to the present invention.

[0050] Figure 6This is a convergence analysis diagram of the temperature distribution of a 100nm filled medium under 10, 20 and 30-layer discretization in the layered framework calculation verification according to the present invention.

[0051] Figure 7 This is a contour map of spectral radiative heat flux and transmission coefficient between the transmitter and receiver according to the present invention.

[0052] Figure 8 The above is a contour map of the spectral radiative heat flux and transmission coefficient between the emitter and the filling medium according to the present invention.

[0053] Figure 9 This is a contour map of the spectral radiative heat flux and transmission coefficient between the filling medium and the receiver according to the present invention.

[0054] Figure 10 This is a comparison diagram of radiation and conduction heat transfer of the receiver in a gap-filled radiation system proposed according to the present invention under different transmitter-receiver temperature differences (ΔT).

[0055] Figure 11 This is a comparison diagram of radiation and conduction heat transfer of the receiver in the gap-filled radiation system proposed according to the present invention under different filling medium thicknesses (d). Detailed Implementation

[0056] The following will provide a clear and complete description of the concept, specific structure, and technical effects of the present invention in conjunction with the embodiments and accompanying drawings, so as to fully understand the purpose, solution, and effects of the present invention. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0057] It should be noted that, unless otherwise specified, when a feature is referred to as "fixed" or "connected" to another feature, it can be directly fixed or connected to the other feature, or indirectly fixed or connected to the other feature. Furthermore, the descriptions of "upper," "lower," "left," "right," "top," and "bottom" used in this invention are only relative to the relative positional relationships of the various components of the invention in the accompanying drawings.

[0058] Furthermore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this specification is for the purpose of describing particular embodiments only and not for limiting the invention. The term "and / or" as used herein includes any combination of one or more of the associated listed items.

[0059] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various elements, these elements should not be limited to these terms. These terms are only used to distinguish elements of the same type from one another. For example, without departing from the scope of this disclosure, a first element may also be referred to as a second element, and similarly, a second element may also be referred to as a first element.

[0060] Reference Figures 1 to 9 In some embodiments, the near-field radiation heat transfer system filled with artificial hyperbolic metamaterial according to the technical solution of the present invention includes an emitter, a receiver, and a filling medium, wherein the filling medium is disposed between the emitter and the receiver; the filling medium is provided with artificial hyperbolic metamaterial, wherein the artificial hyperbolic metamaterial is a potassium-permeable silica nanoporous matrix filling material; wherein the system adopts a fully coupled multiphysics framework that integrates near-field radiation, conduction transport, and nonlinear temperature stratification.

[0061] To overcome the limitations of existing interstitial near-field radiative heat transfer methods, this invention proposes an artificial hyperbolic metamaterial that is potassium (K)-permeable to silica (… This invention utilizes a nanoporous matrix that combines hyperbolic dispersion and low-loss characteristics, without relying on a virtual medium. Furthermore, it establishes a fully coupled multiphysics framework, self-consistently integrating near-field radiative transfer with conductive transfer within the filling medium. Through discrete layering controlled by the principle of energy conservation, it addresses the nonlinear temperature distribution problem and quantifies the radiative energy of all near-field radiative transfer paths. These paths include the interactions between the emitter and the medium, the emitter and the receiver, and the medium and the receiver. This quantifies the heat transfer of these three main radiative transfer paths and considers their coupling effects. Using this invention, the system achieves the following: when the filling medium thickness is 100 nm, the radiative heat flux is comparable to the conductive heat flux at ΔT = 100 K; and at ΔT = 1000 K, the radiative heat flux reaches five times the conductive heat flux, where ΔT represents the temperature difference between the emitter and receiver layers. This result represents the first time that radiation-dominated heat transfer, exceeding conductive heat transfer, has been achieved in a solid-state system, laying the foundation for new methods in high-power-density thermal management and advanced thermophotovoltaic applications.

[0062] In some embodiments of the present invention, the present invention is a near-field radiative heat transfer system filled with artificial hyperbolic metamaterials, see [link to relevant documentation]. Figure 1 The emitter and receiver of the present invention are both doped silicon with a doping concentration of 1020 cm-3. The filling medium with a thickness of d used to excite broadband surface plasmons (SPPs) is composed of a silicon dioxide matrix with uniform through holes and potassium infiltrated therein, forming a low-loss hyperbolic metamaterial that supports hyperbolic phonon polaritons (HPPs).

[0063] Experiments have verified that the synergistic resonance of surface plasmons and hyperbolic phonon polaritons in this invention can significantly enhance near-field radiative heat transfer. Specifically, considering that the temperature gradient is mainly distributed along the vertical direction, the system of this invention can be simplified as follows: Figure 2 The one-dimensional configuration is shown. The multilayer discretization model divides the filling medium into N discrete sublayers ( arrive Each discrete sublayer has a uniform temperature, and its boundary is an emitter (with a fixed temperature TH). (layer) and receiver (fixed temperature TL) The multilayer discretization model considers: first, simultaneous emission / absorption within a finite-temperature filling medium; second, all radiation paths (emitter-medium, emitter-receiver, medium-receiver); and third, conduction and transmission between adjacent sublayers. Specifically, to accurately characterize the temperature distribution within the system after the introduction of thermal conduction, it first considers that after the addition of the filling medium, each part of the system will have mutual near-field radiation emission and absorption. Then, it further considers the mutual coupling of near-field radiation between different media within the system, and then considers the coupling of near-field radiation with thermal conduction between each adjacent layer to obtain the specific temperature of each layer affected by both. At the micro / nano scale, photon tunneling, surface plasmon coupling, and hyperbolic mode excitation jointly enhance interlayer radiation transfer. Therefore, each discrete sublayer j is simultaneously affected by the conductive heat flow (Qcond_j) of the adjacent layer and the cumulative radiative heat flow (Qrad_j) of all other layers. The nonlinear temperature distribution generated by the above-mentioned radiation and conduction coupling is fundamentally different from the classical linear distribution of a purely conductive system.

[0064] In some embodiments of the present invention, in order to obtain the accurate near-field radiative heat flux of the system, the present invention adopts the dyadic Green's function method and the random current source thermal radiation model in combination with the theory of fluctuation electrodynamics.

[0065] Specifically, thermal radiation originates from random current sources within the emitting body; therefore, thermal radiation satisfies the fluctuation and dissipation theorem, as expressed below:

[0066] ;

[0067] In the formula, Indicates position Fluctuating current source at the location, express Fluctuating current source at the location; The vacuum permittivity; an indexed tensor. Defined as ; Let be the Dirac function, which represents the locality of the real space and the frequency space; This is the imaginary part of the dielectric tensor; and Represents the components of three-dimensional real space; where, For frequency ,temperature The average energy of the lower Planck oscillator and These are the reduced Planck constant and Boltzmann constant, respectively; radiative heat flux. Through calculation The ensemble-averaged Poynting vector of the direction is obtained. Discrete sublayer Along at interface j Average spectral Poynting flux density in the direction It can be represented as:

[0068] ;

[0069] In the formula, Represented as frequency ,temperature The average energy of the lower Planck oscillator;

[0070] in, Let be the transfer factor, expressed as:

[0071] ;

[0072] In the formula, The vacuum permittivity, Area of ​​a single cell For the Levi-Civita tensor, and For the dyadic Green's operator, the observation point electromagnetic field at the location and With the source Current correlation at (i.e.) , ),in Indicates position Fluctuating current source at the location; For trace operators, Indicates matrix transpose. Represents the conjugate matrix; sub-layer Absorbed radiation can pass through its two interfaces. Difference calculation; near-field transmission factor By considering all possible in-plane wave vectors Integral transmission coefficient Obtain, transmission coefficient The probability of thermally excited photons propagating from the emitter layer to the receiver layer is characterized and calculated using either rigorous coupled-wave analysis (RCWA) or the scattering matrix method, depending on the structure. During integration... The upper limit is set to ( =0.5 nanometers is the silicon lattice constant). This invention uses a doping concentration of... The Drude model describes the dielectric function of doped silicon.

[0073] In some embodiments of the present invention, the present invention utilizes potassium infiltration into a porous silica matrix filling material. Directional thermal conductivity Its conduction and heat transfer properties are characterized as follows:

[0074] ;

[0075] In the formula, The percentage of potassium in the silica matrix. and Thermal conductivity of nano-thickness silica film and potassium film, respectively Its thermal conductivity with bulk materials The relationship is represented as follows:

[0076] ;

[0077] In the formula, The correlation coefficient of nanostructure (nanofilm is taken as) ), , Knudsen number In the formula To fill the thickness of the medium, The mean free path of phonon transport in the material. It is expressed as follows:

[0078] ;

[0079] In the formula, For material density, Specific heat capacity (by volume) The average group velocity.

[0080] In some embodiments of the present invention, in order to accurately solve the temperature distribution within the filling medium, the present invention establishes a model that couples heat conduction and near-field radiation heat transfer to ensure that the net heat flow of each discrete sublayer is balanced under steady state, that is, the heat flow at each interface is equal. The model is represented as follows:

[0081] ;

[0082] In the formula, , Represents any number of layers. Represents the discrete sublayer and Conductive heat flow at the interface Display Interface The cumulative radiative heat flow from all layers; For the discrete sub-layer and Conductive heat flow at the interface For the interface The cumulative radiative heat flux from all layers is represented as follows:

[0083] ;

[0084] ;

[0085] In the formula, and They represent the first and The temperature of the layer, This indicates the total number of layers.

[0086] In this process, a sufficient number of sublayers N needs to be selected to ensure the convergence of theoretical calculations. A genetic algorithm is used to iteratively solve for the temperature distribution of each sublayer, minimizing the objective function. It is expressed as follows:

[0087] ;

[0088] In the formula, The average heat flux across all interfaces in each iteration is expressed as follows:

[0089] ;

[0090] In some embodiments of this invention, a potassium-infiltrated silica nanocomposite material structure is employed. Through systematic screening of various material combinations, the excellent broadband hyperbolic dispersion and structural stability of silica / potassium, along with its fabrication feasibility, are utilized. It is understood that the core of interstitial near-field radiative heat transfer lies in the rational design of the filling material, while simultaneously optimizing the near-field radiation and heat conduction paths. Low-loss hyperbolic media can increase radiative heat flux by an order of magnitude. This standard requires material selection to exceed ideal models. To meet these dual requirements, the artificial hyperbolic metamaterial of this invention is a potassium (K)-infiltrated silica nanocomposite material. The nanoporous matrix combines hyperbolic dispersion and low loss characteristics, and does not require a virtual medium.

[0091] Specifically, see Figure 3 and Figure 4 As shown, these represent the results based on Brugman's Effective Medium Theory (EMT) and... when the potassium filling rate is 0.1%. The real and imaginary parts of the effective dielectric tensor of the artificial hyperbolic metamaterial are calculated. The shaded area in the figure (…) and The results show that it meets the requirements over a wide spectral range. They exhibit type II and type I hyperbolic dispersions, respectively, supporting high-wavelength vector photon transmission. Their Brugmann Effective Medium Theory (EMT) is expressed as follows:

[0092] ;

[0093] ;

[0094] in, This represents the EMT dielectric function perpendicular to the optical axis. This represents the dielectric function of silicon dioxide. Indicates the fill rate. This represents the EMT dielectric function parallel to the optical axis. This represents the dielectric function of potassium.

[0095] This invention utilizes |Im(ε) within the hyperbolic band EMT )|<< |Re(ε EMT The low-loss characteristics of potassium and silica nanocomposite materials are used to meet the near-field enhancement core conditions determined in previous studies. Specifically, this invention employs a potassium-silica nanocomposite structure, which combines the structural stability of silica with the plasmon response of potassium, overcoming the fundamental limitations of the ideal hyperbolic model and crystal orientation-restricted natural materials, and establishing a general framework for customized metamaterials in the field of thermophotonics.

[0096] See Figure 5 and Figure 6 This invention verifies the reliability of the computing framework through a dual verification path. Specifically, Figure 5 A comparison was made between the exact RCWA solution considering the periodic nanostructure of the filled medium and the solution considering the filled medium as the dielectric tensor of the xy plane. The z-direction is The spectral radiative heat flux of the EMT approximate solution for a uniaxial medium, both in the full working spectrum ( The trend of change is consistent within the range, especially at frequencies lower than [missing information]. The results show good agreement, proving that EMT can be used for subsequent iterative calculations of multilayer temperature fields. Figure 6The convergence of the nonlinear temperature distribution in a 100 nm thick filled medium was analyzed. The 10-layer discretization showed a significant deviation from the exact solution, while the discretization results for 20 and 30 layers were highly consistent (ΔT < 1.5 K at all locations). It should be noted that the difference in total radiative heat flux of the receiver between the 20-layer and 30-layer models of this invention is < 1%, and experiments confirm that convergence is met at N=20. This nonlinear distribution, deviating from the linear conduction prediction, provides preliminary evidence for quantifying the significant radiative contribution in subsequent heat flux analysis.

[0097] See Figure 6 The convergence temperature distribution of the potassium and silica-filled near-field radiative heat transfer system is shown. Figure 7 The spectral radiation contributions of the emitter and filling medium to the receiver were quantified. The results show that radiative heat transfer between the filling medium and the receiver is dominant, almost ten times the contribution of the emitter. Compared to near-field radiative heat transfer in a vacuum gap, the structure of this invention exhibits... and Achieved in the hyperbolic band A multiple increase. And at 0.5, 1.5, The characteristic resonance peak at that location originates from surface plasmon-hyperbolic coupling. Figure 8 and Figure 9 Energy transfer coefficient The contour plot confirms this; specifically, the bright bands at the matching frequencies indicate that the surface plasmons of the doped silicon achieve phase matching with the hyperbolic dispersion of the high-β propagation waves in the filling medium, with the contribution of the filling medium being more significant. This multi-band enhancement is consistent with previous observations of metamaterial-mediated photon tunneling, while simultaneously achieving unprecedented heat flux amplitudes.

[0098] See Figure 10 and Figure 11 This invention compares the variations in radiative and conductive heat flux of the receiver with temperature difference (ΔT) and filling medium thickness (d) in the proposed interstitial solid system. Specifically, Figure 10 The results show that when d = 100 nm, the radiative heat flux and the conductive heat flux are comparable at ΔT = 100 K, marking the first time that radiative-conductive heat flux equivalence has been achieved in an all-solid-state system. Beyond this crossover point, as ΔT increases, the radiative heat flux gradually dominates the heat transfer process: it is twice the conductive heat flux at ΔT = 400 K, four times at ΔT = 700 K, and five times at ΔT = 1000 K. This difference provides an operating window for gap-filling thermophotovoltaic devices: high radiative heat flux ensures power generation efficiency, while suppressed conductive heat flux prevents overheating of the battery. Furthermore, Figure 11The study demonstrates the variations in radiative and conductive heat fluxes with the thickness of the filling medium (50-200 nm) at ΔT=100 K: both decrease monotonically with increasing d, exhibiting a parallel decreasing trend. This nonlinear variation stems from thickness-dependent thermal conductivity and nonlinear near-field radiation effects. The sustained comparability of radiative and conductive heat fluxes across the thickness variation range confirms the macroscopic scalability feasibility of the interstitial radiative system.

[0099] This invention proposes K-penetration Nanoporous metamaterials, as hyperbolic low-loss gap-filling media, overcome the fundamental limitations of near-field radiative heat transfer. Unlike ideal models or natural crystals, the composite material of this invention possesses both broadband hyperbolic dispersion and structural feasibility. Specifically, this invention establishes a fully coupled multiphysics framework integrating near-field radiation, conduction, and nonlinear temperature stratification, achieving radiation-dominated heat transfer in solid-state systems that surpasses conduction heat flow. Specifically, when the metamaterial thickness is 100 nm, the radiative heat flow is increased by five orders of magnitude compared to near-field radiative heat transfer in a vacuum gap; it is comparable to conduction heat flow at ΔT=100K; and reaches five times the conduction heat flow at ΔT=1000K. This research solves the multiphysics coupling problem, representing a paradigm shift by replacing vacuum gaps with functional bulk media. It establishes new methods for high-power-density thermal management, near-field thermophotovoltaics, and industrial waste heat recovery, areas where radiation-dominated heat transfer was previously impossible to achieve in solid-state systems.

[0100] The potassium (K) infiltration into silica (…) provided by this invention Nanoporous hyperbolic metamaterials, as functional gap-filling media, can effectively overcome the scalability problem faced by existing near-field radiation heat transfer methods that utilize evanescent wave tunneling to break the blackbody limit, but are limited by nanoscale vacuum gaps. This invention constructs a fully coupled multiphysics framework that integrates fluctuation electrodynamics, conduction transport, and energy conservation temperature stratification, solving the radiation-conduction coupling problem within the filling medium.

[0101] This invention achieves radiation-dominated heat transfer in solid-state systems, with radiative heat flux exceeding conductive heat flux. Specifically, when a 100nm thick hyperbolic metamaterial is filled between two doped silicon wafers, the radiative heat flux is increased by five orders of magnitude compared to near-field radiative heat transfer in a vacuum gap. At a temperature difference ΔT = 100K, it is comparable to conductive heat flux, and at ΔT = 1000K, it reaches five times the conductive heat flux. This breakthrough stems from the characteristics of broadband hyperbolic dispersion and the synergistic coupling of surface plasmons and hyperbolic polaritons, which is verified by spectral transmission peaks. This invention replaces the vacuum gap with a scalable bulk medium, providing a revolutionary solid-state system solution for high-power-density thermal management, near-field thermophotovoltaics, and industrial waste heat recovery.

[0102] The above description is merely a preferred embodiment of the present invention. The present invention is not limited to the above-described embodiments. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this disclosure, as long as they achieve the same technical effects, should be included within the scope of protection of this disclosure and fall under the protection scope of the present invention. Within the protection scope of the present invention, the technical solutions and / or implementation methods can have various modifications and variations.

Claims

1. A near-field radiative heat transfer system filled with artificial hyperbolic metamaterials, characterized in that, The system includes an emitter, a receiver, and a filling medium, wherein the filling medium is disposed between the emitter and the receiver; the filling medium is provided with an artificial hyperbolic metamaterial, wherein the artificial hyperbolic metamaterial is a potassium-permeable silica nanoporous matrix filling material; wherein the system adopts a fully coupled multiphysics framework that integrates near-field radiation, conduction and transmission, and nonlinear temperature stratification. The system is configured such that when the thickness of the filling medium is 100 nm and the temperature difference ΔT between the emitter and the receiver is greater than or equal to 100 K and less than or equal to 1000 K, the net radiative heat flux transmitted through the filling medium reaches or exceeds the conductive heat flux transmitted through the filling medium.

2. The system according to claim 1, characterized in that, Both the emitter and the receiver are composed of doped silicon, and the silicon dioxide in the artificial hyperbolic metamaterial has uniform through-pores and is infiltrated with potassium.

3. The system according to claim 2, characterized in that, The fully coupled multiphysics framework employs a multi-layer discretized model controlled by the principle of energy conservation to obtain the nonlinear temperature distribution generated by the coupling of radiation and conduction.

4. The system according to claim 3, characterized in that, In the aforementioned multi-layer discretization model The filling medium comprises N discrete sub-layers, each of which has a uniform temperature, and the two side boundaries of each discrete sub-layer are the transmitter and the receiver, respectively. Each of the discrete sublayers is simultaneously subjected to conductive heat flow from the adjacent layer and cumulative radiative heat flow from all other layers.

5. The system according to claim 4, characterized in that, The fully coupled multiphysics framework utilizes the z-direction thermal conductivity of a potassium-infiltrated silica porous matrix filling material. k cond Its conduction and heat transfer properties are characterized as follows: ； In the formula, f The percentage of potassium in the silica matrix. k SiO2,film and k K,film The thermal conductivity of the nano-thickness silica film and potassium film are respectively.

6. The system according to claim 5, characterized in that, The fully coupled multiphysics framework uses a model that combines coupled heat conduction and near-field radiation heat transfer to solve for the temperature distribution within the filling medium. The model for coupled heat conduction and near-field radiative heat transfer is expressed as follows: ； In the formula, Represents the discrete sublayer L i and L i+1 Conductive heat flow at the interface This represents the cumulative radiative heat flux from all layers at interface i; Q cond,j For the discrete sub-layer L j and L j+1 Conductive heat flow at the interface Q rad,j Let be the cumulative radiative heat flux from all layers at interface j.

7. The system according to claim 6, characterized in that, The fully coupled multiphysics framework uses a genetic algorithm to iteratively solve for the temperature distribution of each sublayer, minimizing the objective function. y It is expressed as follows: ； In the formula, Q ave The average heat flux across all interfaces in each iteration is expressed as follows: 。 8. The system according to claim 7, characterized in that, When the potassium filling rate in the artificial hyperbolic metamaterial is 0.1, based on Brugmann's effective medium theory and The real and imaginary parts of the effective dielectric tensor of the artificial hyperbolic metamaterial are calculated; where, This represents the EMT dielectric function parallel to the optical axis. This represents the dielectric function of silicon dioxide. This represents the dielectric function of potassium.

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