Methods and systems for enhancing radiative heat transport of nanoparticles

Abstract

The application provides a method and system for enhancing the heat radiation of nanoparticles. The method comprises: placing a nanoparticle in a heat radiation adjusting system, wherein the heat radiation adjusting system has at least two second objects, at least one of the second objects has a nanoscale size, and the heat radiation adjusting system has at least two second objects containing a first element; determining a second parameter of the heat radiation adjusting system based on a first parameter of the nanoparticle, so that the excitation characteristics of the local phonon polariton of the second object are changed to improve the heat radiation flow of the heat radiation adjusting system, wherein the first parameter comprises the chemical composition and shape of the nanoparticle, and the second parameter comprises at least one of the isotope species of the first element in the second object and the number of the second object. The method and system can greatly increase the heat radiation coefficient of the nanoparticles.

Description

Technical Field

[0001] This application relates to the field of heat transfer regulation technology, specifically to methods and systems for enhancing the radiative heat transport of nanoparticles, and more particularly to a method for synergistically enhancing the radiative heat transport of nanoparticles based on isotope effects and many-body interactions. Background Technology

[0002] Thermal radiation, as one of the three fundamental modes of heat transfer, plays a crucial role in numerous natural phenomena and engineering systems. In recent decades, near-field thermal radiation has garnered significant attention due to its potential to achieve quasi-monochromatic emission and exceed the blackbody limit by several orders of magnitude. This provides unique opportunities for utilizing radiative heat transfer in various energy conversion and thermal management devices. Recently, theoretical findings have shown that near-field radiative heat flux between two parallel polar dielectric plates can be enhanced by more than 1560 times through isotope engineering of surface phonon polarons. With the continuous advancement of isotope-controlled material synthesis techniques, experimental demonstrations and even practical applications of this isotope effect may become increasingly feasible.

[0003] However, current methods and systems for enhancing the radiative thermal transport of nanoparticles, especially those based on isotope effects and multibody interactions, still require further research and improvement. Summary of the Invention

[0004] In view of the above problems, this application provides a method and system for enhancing the radiative heat transport of nanoparticles. The method and system are based on the synergistic enhancement of the radiative heat transport of nanoparticles by the isotope effect and many-body interaction, which can significantly enhance the near-field heat flux and improve the radiative heat transfer coefficient by several orders of magnitude.

[0005] In one aspect of this application, a method for enhancing the radiative thermal transport of nanoparticles is proposed. The method includes: placing the nanoparticles in a thermal radiation conditioning system having at least two second objects, at least one of the second objects having a nanometer-scale size, the nanoparticles forming an element containing at least one first element, the first element being an element with stable isotopes, and the at least two second objects in the thermal radiation conditioning system containing the first element; determining second parameters of the thermal radiation conditioning system based on first parameters of the nanoparticles, such that the excitation characteristics of localized phonon polaritons in the second objects are altered to increase the thermal radiation flux of the thermal radiation conditioning system, the first parameters including the chemical composition and shape of the nanoparticles, and the second parameters including the isotopic species of the first element in the second objects and at least one of the quantities of the second objects.

[0006] This method can significantly improve the radiative heat transfer coefficient by adjusting the second parameter, taking into account both isotope effects and the synergistic effect of multi-object interactions.

[0007] According to an embodiment of the present invention, determining the second parameter of the thermal radiation modulation system based on the first parameter of the nanoparticles includes:

[0008] (1) Calculate the radiative heat transfer coefficient h between the nanoparticles and the second object when the thermal radiation conditioning system contains only the nanoparticles and the second object, and the second object has different chemical compositions and / or shapes, in order to determine the chemical composition and / or shape of the second object.

[0009] The chemical composition of the second object is different in the following ways: the second object and the nanoparticles have the same chemical composition, and the first element in the nanoparticles is replaced by an isotope.

[0010] (2) Calculate the heat transfer coefficient enhancement ratio Φ of the thermal radiation conditioning system as the number of the second objects in the thermal radiation conditioning system increases sequentially, so as to determine the number of the second objects.

[0011] According to an embodiment of the present invention, the radiative heat transfer coefficient h is a function of a specific operating temperature T and the interparticle distance d, and the radiative heat transfer coefficient h is determined by the following formula:

[0012]

[0013] Among them, h ω It is the spectral thermal conductivity coefficient, and d is the distance between the nanoparticle and the second object.

[0014] τ(ω) is the energy transfer probability determined by the vector Green's function.

[0015] Θ(ω,T) is obtained from the following equation (2):

[0016]

[0017] in To reduce Planck's constant, k B It is the Boltzmann constant.

[0018] According to an embodiment of the present invention, the heat transfer coefficient enhancement ratio Φ is determined by the following formula (3):

[0019]

[0020] Wherein, h is the radiative heat transfer coefficient between the nanoparticles and the second object, h minThe minimum radiative heat transfer coefficient between the two objects in the aforementioned thermal radiation regulation system.

[0021] According to an embodiment of the present invention, the nanoparticles and the second object support surface polaritons, and the number of objects participating in radiative heat transfer in the thermal radiation regulation system is greater than or equal to three.

[0022] In another aspect of this application, a thermal radiation modulation system is proposed. The thermal radiation modulation system is used to enhance the radiative heat transport of nanoparticles. The system includes at least two second objects, at least one of which has a nanometer-scale size. The system is configured to adjust a second parameter based on a first parameter of the nanoparticles to increase the thermal radiation flux of the system. The first parameter includes the chemical composition and shape of the nanoparticles, and the second parameter includes the isotopic species of a first element in the second objects and at least one of the quantities of the second objects.

[0023] This system can coordinate isotope response and many-body interaction to significantly improve the heat transfer coefficient of the system.

[0024] According to an embodiment of the present invention, the shape of the second object includes at least one of a particle, a plate, a cavity, and a cylinder.

[0025] According to an embodiment of the present invention, the thermal radiation conditioning system has at least one geometric dimension larger than the size of the nanoparticles by at least 10. 2 times.

[0026] According to an embodiment of the present invention, the nanoparticles include c 11 BN particles, the second object includes c 11 BN particles, c 11 The thermal radiation conditioning system comprises at least one of BN plate and Ag plate, and has at least two of the c 11 BN particles, or at least one c 11 BN particles and a c 11 BN plate, or at least two Ag plates.

[0027] According to an embodiment of the present invention, the adjustment of the second parameter of the thermal radiation regulation system based on the first parameter of the nano-example is performed using the method described above. Attached Figure Description

[0028] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0029] Figure 1 This is a schematic diagram of the method for synergistically enhancing the radiative thermal transport of nanoparticles based on isotope effects and many-body interactions, as described in this application.

[0030] Figure 2 The graph shows the relationship between the radiative heat transfer coefficient of a particle-plate two-body system with different isotopic compositions and the particle-plate distance.

[0031] Figure 3 The graph shows the relationship between the phonon polariton excitation frequency of cubic boron nitride particles and plates and the ratio of boron isotopes.

[0032] Figure 4 The graph shows the relationship between the spectral radiative heat transfer coefficients of particle-plate two-body systems with different isotopic compositions under different particle-plate spacings.

[0033] Figure 5 This is a graph showing the relationship between the radiative heat transfer coefficient and the spacing in Example 1;

[0034] Figure 6 This is a graph showing the relationship between the enhancement ratio of the heat transfer coefficient and the spacing in another example 1;

[0035] Figure 7 This is a graph showing the relationship between the enhancement ratio of the heat transfer coefficient and the spacing in another example 1;

[0036] Figure 8 This is a graph showing the relationship between the enhancement ratio of the heat transfer coefficient and the spacing in Example 1.

[0037] Figure 9 This is a graph showing the relationship between the radiative heat transfer coefficient and the spacing in Example 2;

[0038] Figure 10 This is a graph showing the relationship between the enhancement ratio of the heat transfer coefficient and the spacing in another example, Example 2.

[0039] Figure 11 This is a graph showing the relationship between the enhancement ratio of a heat transfer coefficient and the spacing in Example 3;

[0040] Figure 12 This is a graph showing the relationship between the increase in heat transfer coefficient and the spacing in Example 3. Detailed Implementation

[0041] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0042] In one aspect of this application, a method for enhancing the radiative thermal transport of nanoparticles is proposed. The method includes: placing the nanoparticles in a thermal radiation conditioning system having at least two second objects, at least one of the second objects having a nanometer-scale size, the nanoparticles forming an element containing at least one first element, the first element being an element with stable isotopes, and the at least two second objects in the thermal radiation conditioning system containing the first element; determining second parameters of the thermal radiation conditioning system based on first parameters of the nanoparticles, such that the excitation characteristics of localized phonon polaritons in the second objects are altered to increase the thermal radiation flux of the thermal radiation conditioning system, the first parameters including the chemical composition and shape of the nanoparticles, and the second parameters including the isotopic species of the first element in the second objects and at least one of the quantities of the second objects.

[0043] This method can significantly improve the radiative heat transfer coefficient by adjusting the second parameter, taking into account both isotope effects and the synergistic effect of multi-object interactions.

[0044] To better understand the system and method proposed in this application, the principles by which the method and system proposed in this application achieve the aforementioned beneficial effects will be explained below:

[0045] When free-space photons couple with polarization charges such as electrons, phonons, and excitons within a material, quasiparticles are excited, thus overcoming the diffraction limitations of traditional optics and enabling subwavelength modulation of micro / nano devices. Among these quasiparticles, dielectric-supported phonon polaritons (SPhPs) dominate in the infrared band. This allows for ultra-low optical loss, long lifetime, and high tunability. When the distance between two radiators is less than the thermal wavelength corresponding to their respective temperatures... At this time, due to the near-field coupling of polaritons, the radiation heat transfer coefficient can exceed the blackbody radiation limit by several orders of magnitude. This phenomenon is called near-field thermal radiation.

[0046] like Figure 1As shown, for two nanoparticles, radiative heat transfer is determined by the distance between them and their radiation characteristics. Introducing other objects increases the number of radiative heat transfer paths in the system. Furthermore, many-body interactions also affect the original radiative heat transfer path between the two particles. Overall, the radiative heat transfer coefficient between the two particles is significantly enhanced. Moreover, when the isotopic composition of the two radiators differs, their radiative heat transfer coefficient can change by three orders of magnitude.

[0047] Compared to two parallel plate systems, multibody systems are more complex, but they also offer additional degrees of freedom for thermal control. This is because the electromagnetic environment of a two-body system can be significantly altered by adding objects, leading to unique nonlinear dynamics and collective behavior in multibody systems. With the rapid development of nanotechnology and materials science, precise control of isotope ratios within materials and large-area stable growth are becoming increasingly possible. This provides technical support for adjusting the chemical composition of other thermally radiatively involved objects in a thermal radiation regulation system based on the isotopic elements contained in nanoparticles. Therefore, isotopic engineering of some of the participating media in a multibody system can further enhance the intensity of radiative heat transfer between key materials.

[0048] Radiative heat transfer can be viewed as being determined by the propagation probability of electromagnetic waves with different frequency points and wave vectors between two radiators. Because the excitation frequencies of phonon polaritons differ in dielectrics with different geometries, the heat flow between radiators composed of identical materials is not necessarily maximized in a multi-body system involving objects of varying geometries. If the two radiators have different material compositions and also different geometries, the excitation frequencies of their polaritons may be closer, thus significantly increasing the propagation probability of electromagnetic waves between them.

[0049] Therefore, the method proposed in this application, while considering the isotope effect, also compares and examines the influence of multiple systems (i.e., systems with more than two objects participating in radiative heat transfer) on radiative heat transfer. Specifically, the method proposed in this application, based on the first parameter of the nanoparticles, determines the second parameter of the thermal radiation regulation system. This may involve first adjusting the isotopes contained in the second object in the thermal radiation regulation system, i.e., the type, quantity, abundance, etc. of the first element, to select the isotopic composition of the second object that best enhances radiative heat transfer. Subsequently, based on the determined isotopic composition of the second object, the number of particles in the thermal radiation regulation system is adjusted to further enhance radiative heat transfer through the interaction of multiple systems.

[0050] According to an embodiment of the present invention, the nanoparticles and the second object support surface polaritons, and the number of objects participating in radiative heat transfer in the thermal radiation regulation system can be greater than or equal to three.

[0051] In some embodiments, the nanoparticles are preferably materials that exhibit a large percentage change in isotope ratio relative to the overall change in the material's relative molecular mass and that support localized surface polaritons. The second object is also preferably a material that supports surface polaritons at the operating temperature, and may be the same as or different from the nanoparticles.

[0052] According to a specific embodiment of this application, determining the second parameter of the thermal radiation modulation system based on the first parameter of the nanoparticles may include the following steps:

[0053] (1) Calculate the radiative heat transfer coefficient h between the nanoparticle and the second object when the thermal radiation conditioning system has only the nanoparticle and the second object, and the second object has different chemical composition and / or different shape, so as to determine the chemical composition and / or shape of the second object.

[0054] (2) Calculate the heat transfer coefficient enhancement ratio Φ of the thermal radiation conditioning system as the number of the second objects in the thermal radiation conditioning system increases sequentially, so as to determine the number of the second objects.

[0055] Specifically, in step (1), the radiative heat transfer coefficient h between the nanoparticle and the second object is first calculated when the thermal radiation conditioning system has only one nanoparticle to enhance radiative heat transfer and the second object, and the second object has different chemical composition and / or different shape.

[0056] When considering multibody systems, the isotopic composition and geometry of the objects involved in radiative heat transfer have a significant impact on near-field thermal radiation. The following section uses the radiative heat transfer characteristics of a particle-plate two-body system and its isotopic effects as examples to illustrate the influence of isotopic effects and object geometry on radiative heat transfer:

[0057] cBN (cubic boron nitride) with isotopic tunability using nanoparticles was employed. 11 B isotope enrichment of c 11 BN(0%) 10 B) Taking the plate as the second object as an example, illustrate the influence of different isotopic compositions and the shape of the second object on the radiative heat transfer coefficient h:

[0058] It should be noted here that, without loss of generality, in this embodiment, the chemical composition of the second object and the nanoparticles is fixed first, and the radiative heat transfer coefficient h between the particles and the second object is examined as the distance between them increases, given the shape of the second object:

[0059] Let the second object have a chemical composition of C. 11 BN (inclusive of 0%) 10 B) The flat plate, with nanoparticles as...10 B isotope enrichment of c 10 BN (100%) 10 B) Nanoparticles. (Reference) Figure 2 The total radiative heat transfer coefficient of two cBN particles with different isotopic ratios varies with the particle-plate distance D from 1 micrometer to 20 nanometers. It can be seen that the radiative heat transfer coefficient h increases significantly as the particle-plate distance D decreases. This is a typical characteristic of near-field thermal radiation caused by photon tunneling due to polariton coupling. Meanwhile, when D is between 1 micrometer and 280 nanometers, c... 11 BN particles-c 11 The radiative heat transfer coefficient of the BN plate combination is greater than that of c. 10 BN particles-c 11 BN plate assemblies: The near-field enhancement effect between two parallel plates made of the same material is generally greater than that between different materials with lower electromagnetic mode matching. However, when D drops below 100 nm, the radiative heat transfer coefficient of the c10BN-c11BN (plate) assemblies remains consistently higher.

[0060] The above results demonstrate that the mode-matching condition between two objects depends not only on material properties but also on geometry. For radiators of different shapes, the excitation frequencies of their polaritons are not the same. For example, the polariton excitation frequency of nanoparticles needs to satisfy ε(ω) pt The condition )=-2, while the polariton excitation frequency of an infinitely thick plate needs to satisfy ε(ω)=-2. pl )=-1 condition.

[0061] refer to Figure 3 The phonon polariton excitation frequencies of cubic boron nitride particles and plates vary with the boron isotope ratio, as shown in the figure. Specifically, the excitation frequencies of the two phonon polaritons in cubic boron nitride materials with different geometries all change with the boron isotope ratio. 10 The excitation frequency ω of the phonon polaritons in the material increases with increasing B. For a given isotopic ratio, the excitation frequency ω of the phonon polaritons in the material's flat plate increases. pl It must be higher than the local phonon polariton excitation frequency ω of the particle. pt For c 11 BN, its ω pl and ω pt They are 2.338×10 14 rad / s and 2.287×10 14 rad / s; for c 10 BN, its ω pl and ω pt They are 2.402×10 14 rad / s and 2.35×10 14 rad / s.

[0062] In other words, if these polaritonic modes can be excited and coupled, c 10 The localized phonon polariton of the BN particle and c 11 The surface phonon polaritons of the BN plate are closer together, better matched, and more strongly coupled. Therefore, the reference... Figure 4 When D = 20 nanometers, c 10 BN particles-c 11 The radiative heat transfer coefficient between BN plates is very large, as shown in the spectral radiative heat transfer coefficients of particle-plate two-body systems with different isotopic compositions at D = 20 nm. However, as... Figure 4 As shown, at D = 1 micrometer, the coupling weakens due to the exponential decay of these phonon resonance modes with increasing distance, while c 11 BN nanoparticles and c 11 The BN plate exhibits a stronger contribution of non-resonant modes at lower frequencies. 11 BN particles-c 11 The radiative heat transfer coefficient is greater between BN plates.

[0063] The results of the above embodiments demonstrate that, under certain operating conditions, the radiative heat transfer coefficient between different geometries, or even between different materials, can be controlled by adjusting the isotope ratio.

[0064] In some preferred embodiments of this application, the geometric dimensions of the nanoparticles can be much smaller than other geometric dimensions in the system to satisfy the requirements of the dipole approximation description. Specifically, the radius of the nanoparticles is much smaller than the dimensions of other characteristic systems, such as the interparticle distance, the distance between the particle and the plate, the thickness of the plate, the skin depth of the material, and the thermal wavelength. These conditions can be obtained by adjusting relevant parameters of the second object. Under the dipole approximation conditions, the size of the nanoparticles does not affect the enhancement effect on the heat transfer coefficient in this invention.

[0065] Preferably, the polarizability α can be used to measure the influence of an external electromagnetic field on the electron cloud surrounding the particle, which determines the particle's absorption, extinction, and scattering. Under the dipole approximation, the optical polarizability α of the nanoparticle can be described by the Clausius-Mossotti formula:

[0066]

[0067] Where R is the particle radius, ω is the angular frequency, and ε is the frequency-dependent complex permittivity of the material.

[0068] When photons interact with particles such as electrons, phonons, and excitons inside a material, the response of these particles to the photons determines the material's absorption, transmission, and reflection properties, thereby determining the material's reflectivity, transmittance, and absorptivity for photons of a specific wavelength. According to the fluctuation dissipation theorem, the radiative heat transfer coefficient between two radiators can be written as the aforementioned equation (1).

[0069] According to embodiments of the present invention, unless otherwise specified, the radiative heat transfer coefficient h is a function of a specific operating temperature T and the interparticle distance d. Specifically, the radiative heat transfer coefficient h is determined by the following formula:

[0070]

[0071] Among them, h ω It is the spectral thermal conductivity coefficient, and d is the distance between the nanoparticle and the second object.

[0072] τ(ω) is the energy transfer probability determined by the vector Green's function.

[0073] Θ(ω,T) is obtained from the following equation (2):

[0074]

[0075] in To reduce Planck's constant, k B It is the Boltzmann constant.

[0076] Unless otherwise specified in this application, those skilled in the art can determine the energy transfer probability τ(ω) using the vector Green's function according to actual needs. The vector Green's function is a commonly used tool to describe the response of a vector field, representing the vector field generated at a given location and direction due to the application of a vector point source at another location.

[0077] Therefore, based on the above operations, the isotopic composition and / or shape of the second object can be changed, such as making the second object a plate, particle, or other shaped object. The radiative heat transfer coefficient h between the second object and the nanoparticles can be calculated when the isotopic abundance, isotopic type, and / or shape of the second object are different, thus determining the second object with a greater enhancement effect. Subsequently, the aforementioned step (2) can be performed:

[0078] The heat transfer coefficient enhancement ratio Φ of the thermal radiation conditioning system is calculated as the number of the second objects in the thermal radiation conditioning system increases sequentially, in order to determine the number of the second objects.

[0079] As mentioned earlier, when other objects are introduced into the system, especially when two nanoparticles are present, the local electromagnetic density of states between the two nanoparticles can be better matched over a wider spectral range, and the radiative heat transfer coefficient will be significantly enhanced. If the isotope effect between the two nanoparticles is simultaneously adjusted, the synergistic effect on the radiative heat transfer coefficient between the two nanoparticles can be greatly improved, even by eight orders of magnitude.

[0080] Specifically, in step (2), the number of second objects in the thermal radiation conditioning system can be increased sequentially, and the heat transfer coefficient enhancement ratio Φ of the thermal radiation conditioning system can be calculated. According to an embodiment of the present invention, the heat transfer coefficient enhancement ratio Φ is determined by the following formula (3):

[0081]

[0082] Wherein, h is the radiative heat transfer coefficient between the nanoparticles and the second object, h min The minimum radiative heat transfer coefficient between the two objects in the aforementioned thermal radiation regulation system.

[0083] For example, in some specific embodiments, the number of second objects in the system can be increased sequentially according to the situation of the second object determined in step (1), and the value of the increase in the heat transfer coefficient of the system by each additional second object can be calculated. By selecting the number of second objects with a larger value of Φ, the number of objects in the thermal radiation regulation system can be determined. Thus, based on the isotope effect, an exponential enhancement of radiative heat transfer can be achieved through the interaction of multiple systems.

[0084] In another aspect of this application, a thermal radiation modulation system is proposed. In some embodiments, the system can utilize the methods described above to achieve the thermal radiation enhancement effect of nanoparticles.

[0085] According to an embodiment of this application, a thermal radiation modulation system is used to enhance the radiative heat transport of nanoparticles. The thermal radiation modulation system includes at least two second objects, at least one of which has a nanometer-scale size. The thermal radiation modulation system is configured to adjust a second parameter of the thermal radiation modulation system based on a first parameter of the nanoparticles to improve the radiative heat transfer coefficient of the thermal radiation modulation system. The first parameter includes the chemical composition and shape of the nanoparticles, and the second parameter includes the isotopic species of a first element in the second objects and at least one of the number of the second objects.

[0086] This system can coordinate isotope response and many-body interaction to significantly improve the heat transfer coefficient of the system.

[0087] According to an embodiment of the present invention, the shape of the second object includes at least one of a particle, a plate, a cavity, and a cylinder.

[0088] According to an embodiment of the present invention, the thermal radiation conditioning system has at least one geometric dimension larger than the size of the nanoparticles by at least 10. 2 For example, at least one of the various geometric dimensions of the second object can be much larger than the size of the nanoparticles, thus making the system of nanoparticles and the second object suitable for the dipole approximation description: the geometric dimensions of the nanoparticles are much smaller than the other geometric dimensions to satisfy the approximation description. Specifically, the radius of the nanoparticles is much smaller than the dimensions of other characteristic systems, such as the distance between particles, the distance between particles and the plate, the thickness of the plate, the skin depth of the material, and the thermal wavelength. Under the dipole approximation conditions, the size of the nanoparticles does not affect the enhancement effect on the heat transfer coefficient in this invention, thus having a wider range of applications.

[0089] According to an embodiment of the present invention, the nanoparticles include c 11 BN particles, the second object includes c 11 BN particles, c 11 The thermal radiation conditioning system comprises at least one of BN plate and Ag plate, and has at least two of the c 11 BN particles, or at least one c 11 BN particles and a c 11 BN plate, or at least two Ag plates.

[0090] According to an embodiment of the present invention, the adjustment of the second parameter of the thermal radiation regulation system based on the first parameter of the nano-example is performed using the method described above.

[0091] In summary, the method proposed in this application can significantly enhance the thermal radiation of nanoparticles, with the radiative heat transfer coefficient h being increased by several orders of magnitude.

[0092] The methods and systems described above in this application will be explained in detail below through specific embodiments. In the following embodiments, unless otherwise specified, R represents the radius of the nanoparticle, which is set to 5 nm to satisfy the dipole approximation condition; d represents the distance between the two farthest nanoparticles; the temperature of the high-temperature nanoparticles is set to 300.01 K; and the temperature of the low-temperature nanoparticles is set to 300 K. Cubic boron nitride is selected as the nanoparticle material to ensure that its phonon polaritons can be excited at the set temperature. The isotopic ratio of boron in the cubic boron nitride is adjustable. It should be specifically noted here that, in the embodiments, only two cubic boron nitride materials enriched with different isotopes are considered, namely c 10 BN and c 11 BN.

[0093] Example 1:

[0094] refer to Figure 5 The distance d between the two outermost nanoparticles ranges from 10R to 2000R; first consider the combination of only two nanoparticles, where the isotopic pairing of the two nanoparticles is c. 11 BN-c 10 At BN, the radiation heat transfer coefficient is Figure 5 As shown by the lower dashed line.

[0095] Furthermore, when considering only the mass effect of isotopes, c 10 BN nanoparticles replaced with c 11 BN nanoparticles, forming c 11 BN-c 11 BN combination. Furthermore, considering only the mass effect of isotopes resulting in materials with completely identical c-structures... 11 BN-c 11 The radiative heat transfer coefficient of the BN nanoparticle combination is significantly enhanced across all particle spacings. When d = 10R, the original c 11 BN-c 10 The radiative heat transfer coefficient between BN nanoparticle assemblies was enhanced by 4400 times. The enhancement ratio increased with increasing interparticle spacing. When the distance between nanoparticles was large, the enhancement ratio of the radiative heat transfer coefficient was 5530.

[0096] Furthermore, when only many-body interactions are considered, in the original c 11 BN-c 10 A c is inserted between the BN nanoparticle assemblies. 11 BN nanoparticles, utilizing the interaction between introduced nanoparticles and existing particles, form c 11 BN-c 11 BN-c 10 For example, in a BN three-particle system, the radiative heat transfer coefficient is... Figure 6 As shown.

[0097] Furthermore, considering only many-body interactions, c 11 BN-c 11 BN-c 10 In the BN three-particle system, the original c 11 BN-c 10 The radiative heat transfer coefficient between BN nanoparticles only increases at smaller interparticle spacings (d < 30R). When d = 10R, the original c 11 BN-c 10 The radiative heat transfer coefficient between the BN nanoparticle assemblages was enhanced by 17-fold. Since the localized surface phonon polaritons of the nanoparticles decay exponentially with distance, the many-body interaction in the aforementioned three-body system becomes extremely weak when the distance between the nanoparticles is large; only considering the many-body interaction, c... 11 BN-c11 BN-c 10 The enhancement effect of the BN three-particle system on the heat transfer coefficient is almost zero.

[0098] Furthermore, the results show that the three-particle system formed by considering only many-body interactions and ignoring isotope effects is different from the original c 11 BN-c 10 Compared to BN nanoparticles, the enhancement effect on the radiative heat transfer coefficient is very limited, and is two orders of magnitude smaller than the enhancement of the heat transfer coefficient by using the isotope effect in a two-body system.

[0099] Furthermore, this embodiment 1 considers both isotope effects and introduces many-body interactions to form an isotope-tunable three-particle system, with a radiative heat transfer coefficient comparable to, for example... Figure 7 As shown in the diagram.

[0100] like Figure 7 As shown, in the multi-isotope tunable three-particle system formed in Example 1, compared with the original c 11 BN-c 10 Compared to BN nanoparticles, c 11 BN-c 11 BN-c 11 The radiative heat transfer coefficient of the BN three-particle system increases sharply at all spacings.

[0101] When the spacing is small (d < 34R), c 11 BN-c 11 BN-c 11 The heat transfer coefficient of the BN three-particle system can be increased by up to four orders of magnitude. When c 11 BN-c 11 BN-c 11 In the BN three-particle system, when the distance between the two outermost particles is d = 10R, besides the three c... 11 In addition to the very strong local phonon polariton resonances between BN particles, the system also exhibits configurational resonances caused by the interaction of three particles at a relatively close distance, resulting in a heat transfer coefficient enhancement ratio of 16464.

[0102] When c 11 BN-c 11 BN-c 11 In a BN three-particle system, the maximum enhancement of the heat transfer coefficient reaches 55700 when the distance between the two outermost particles is d = 16R. This enhancement is at least an order of magnitude higher than that of a three-particle system with a single isotope effect or one where the isotope is not tunable. When the distance between nanoparticles is larger, due to the decay of local phonon polaritons, the enhancement of the heat transfer coefficient approaches the result considering only the isotope effect, which is 5530.

[0103] refer to Figure 8The comparison of the enhancement ratio of the radiative heat transfer coefficient shown shows that, when only considering the influence of isotope effects and many-body interactions on the enhancement ratio of the radiative heat transfer coefficient, the three-particle system with adjustable multiple isotopes has the largest enhancement ratio of the heat transfer coefficient at all distances.

[0104] Example 2:

[0105] Select c in Example 1 11 BN-c 10 The combination of B and N nanoparticles serves as a reference benchmark for the effectiveness of this invention.

[0106] The difference from Example 1 is that the third object introduced in this example is not an isotope-tunable particle, but an isotope-tunable cBN plate (pl).

[0107] Specifically, based on Example 1, an isotope-tunable particle-plate system is formed, with reference to... Figure 9 When the distance between the two particles and the plate is d = 6R (i.e., d / R = 6), the difference between the two particles and the plate is the same as the original c. 11 BN-c 10 Compared to the BN two-nanoparticle system, c 11 BN-c 11 BN-c 11 In BN(pl), the radiative heat transfer coefficient of the particle-plate system is enhanced by more than three orders of magnitude at all spacings.

[0108] When c 11 BN-c 11 BN-c 11 In the BN(pl) particle-plate system, when the distance d between the two outermost particles is 10R, the localized phonon polariton resonance between the two particles dominates. Due to isotope effects, compared to the original mode that could not couple, the localized phonon polariton resonance between the two particles is significantly stronger. 11 BN-c 10 BN two-particle combination, such as Figure 10 As shown, the heat transfer coefficient enhancement ratio is 5510.

[0109] Furthermore, such as Figure 10 As shown, when c 11 BN-c 11 BN-c 11 In the BN(pl) particle-plate system, when the distance d between the two outermost particles is 400R, the local phonon polariton intensity between the two particles decreases sharply, but the c in the system... 11 The importance of the BN plate as a new radiation transmission channel becomes apparent at this point.

[0110] Furthermore, such as Figure 10As shown, due to the small distance between the particles and the plate (i.e., d / R = 6), there is also a strong mode coupling between the nanoparticles and the plate, which dominates at d = 400R. Compared to the original c 11 BN-c 10 The combination of two BN particles resulted in a maximum heat transfer coefficient enhancement of 3.48 × 10⁻⁶. 8 This means that the heat transfer coefficient is increased by more than eight orders of magnitude.

[0111] Example 3:

[0112] The difference from Examples 1 and 2 is that two silver plates are introduced as a second object in this example. The two silver plates are 1 micrometer thick, forming a parallel silver cavity that confines the two nanoparticles within the cavity, creating an isotope-tunable particle-silver cavity many-body system. Figure 11 As shown.

[0113] In this embodiment 3, when the distance H between the two silver plates is 10R, as follows: Figure 11 As shown, compared with the original c 11 BN-c 10 Compared to the BN two-nanoparticle system, the resulting Ag-c 11 BN-c 11 The radiative heat transfer coefficient of the BN-Ag particle-silver cavity many-body system is enhanced by nearly two orders of magnitude at all spacings.

[0114] Furthermore, at d = 22R, due to the absorption of high-temperature particle thermal radiation energy by the non-resonant frustrated mode of the silver cavity material, Ag-c is formed. 11 BN-c 11 The BN-Ag particle-silver cavity multibody system has the smallest increase in heat transfer coefficient, at only 90%.

[0115] Furthermore, when d>22R, since the silver cavity material confines the radiative energy between the two particles within the cavity, considering energy conservation, the enhancement effect of the silver cavity on the heat transfer coefficient between the two nanoparticles increases with the increase of the spacing, reaching eight orders of magnitude in the maximum spacing range (d>945R).

[0116] Example 4:

[0117] Unlike Example 3, different cavity materials supporting surface wave excitation frequencies were used to enhance the radiative heat transfer coefficient between the two nanoparticles.

[0118] Although the silver cavity material enhances the radiative heat transfer coefficient between nanoparticles by more than two orders of magnitude, the surface modes of the silver material can only be excited in the ultraviolet band and cannot resonate with the modes of nanoparticles that support surface excitation polaritons in the infrared band. Therefore, the enhancement ratio of the heat transfer coefficient can be further improved.

[0119] In this embodiment, the dielectric function of the cavity material is set to be described using the Durud model.

[0120] Furthermore, the Trud model can be expressed as:

[0121]

[0122] For simplicity, this embodiment 4 assumes ε ∞ =4, and fix Γ to 1×10 11 rad / s. By controlling the surface equivalent plasma frequency of the hypothetical material to ω p As a key parameter, it can achieve mode resonance matching or mismatch between the cavity wall material and the two nanoparticles inside the cavity.

[0123] The thickness of the hypothetical cavity material plates in Example 4 is 1 micrometer. For example... Figure 12 As shown, after forming a particle-hypothetical material cavity four-body system, the thermal transfer coefficient is enhanced by isotope engineering of the particles in the cavity, which affects the ω... p Very sensitive.

[0124] refer to Figure 12 , in ω p =2.561×10 14 Hypo-c formed at rad / s 11 BN-c 11 The radiative heat transfer coefficient of the BN-Hypo combination can be higher than that of c. 11 BN-c 10 The BN two-particle combination is seven orders of magnitude larger.

[0125] When ω p =2.561×10 14 At rad / s, the cavity material can react with c 11 BN nanoparticles generate strong mode resonances, while the cavity confines heat flow within the cavity, thus enabling the particle-hypothetical material cavity four-body system to achieve a seven-order-of-magnitude enhancement in heat transfer coefficient.

[0126] Furthermore, in contrast, when ω p Gradually moving away from 2.561×10 14 At rad / s, the surface mode of the cavity material cannot be compared with c. 11 The resonance of BN nanoparticles causes a sharp decrease in the proportion of increased heat transfer coefficient.

[0127] When ω p Less than 2×10 14 rad / s or greater than 4.4 × 10 14 At rad / s, the heat transfer coefficient is enhanced to below 6000.

[0128] 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 to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0129] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0130] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0131] Unless otherwise stated, the terms used in this application have their common meanings as commonly understood by those skilled in the art. Unless otherwise stated, the values ​​of the parameters mentioned in this application can be measured using various measurement methods commonly used in the art (e.g., they can be tested according to the methods given in the embodiments of this application).

[0132] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for enhancing the radiative thermal transport of nanoparticles, characterized in that, include: The nanoparticles are placed in a thermal radiation modulation system having at least two second objects, at least one of which has a nanometer-scale size. The elements forming the nanoparticles include at least one first element, which is an element with a stable isotope, and the thermal radiation regulation system has at least two second objects containing the first element. Based on the first parameter of the nanoparticles, a second parameter of the thermal radiation modulation system is determined, thereby altering the excitation characteristics of the localized phonon polaritons of the second object to increase the thermal radiation flux of the thermal radiation modulation system. The first parameter includes the chemical composition and shape of the nanoparticles. The second parameter includes at least one of the isotopic species of the first element in the second object and the quantity of the second object. Based on the first parameter of the nanoparticles, determining the second parameter of the thermal radiation modulation system includes: (1) Calculate the radiative heat transfer coefficient h between the nanoparticles and the second object when the thermal radiation conditioning system contains only the nanoparticles and the second object, and the second object has different chemical compositions and / or shapes, in order to determine the chemical composition and / or shape of the second object. The chemical composition of the second object includes: the second object and the nanoparticles have the same chemical composition, and the first element in the nanoparticles is replaced by isotopes; (2) Calculate the increase in heat transfer coefficient of the thermal radiation conditioning system as the number of the second objects in the thermal radiation conditioning system increases sequentially. To determine the quantity of the second object; Wherein, the radiative heat transfer coefficient h is a function of a specific operating temperature T and interparticle distance d, and the radiative heat transfer coefficient h is determined by the following formula: in, It is the spectral thermal conductivity coefficient, and d is the distance between the nanoparticle and the second object. τ(ω) is the energy transfer probability determined by the vector Green's function. Obtained from the following formula (2): （2） in To reduce Planck's constant, k B It is the Boltzmann constant.

2. The method according to claim 1, characterized in that, The heat transfer coefficient enhancement ratio Determined by the following formula (3): in, The radiative heat transfer coefficient between the nanoparticles and the second object is... The minimum radiative heat transfer coefficient between the two objects in the aforementioned thermal radiation regulation system.

3. The method according to claim 1 or 2, characterized in that, The nanoparticles and the second object support surface polaritons, and the number of objects participating in radiative heat transfer in the thermal radiation regulation system is greater than or equal to three.

4. A thermal radiation regulation system, characterized in that, The thermal radiation modulation system is used to enhance the radiative heat transport of nanoparticles, and the thermal radiation modulation system includes: At least two second objects, at least one of which has a nanometer-scale size. The thermal radiation modulation system is configured to adjust a second parameter of the thermal radiation modulation system based on a first parameter of the nanoparticles to increase the thermal radiation flux of the thermal radiation modulation system. The first parameter includes the chemical composition and shape of the nanoparticles. The second parameter includes at least one of the isotope types of the first element in the second object and the quantity of the second object. The adjustment of the second parameter of the thermal radiation regulation system based on the first parameter of the nanoparticle is performed using the method described in any one of claims 1-3.

5. The thermal radiation regulation system according to claim 4, characterized in that, The shape of the second object includes at least one of a particle, a plate, a cavity, and a cylinder.

6. The thermal radiation regulation system according to claim 4 or 5, characterized in that, The thermal radiation regulation system has at least one geometric dimension that is at least 10 times larger than the size of the nanoparticles. 2 times.

7. The thermal radiation conditioning system according to claim 6, characterized in that, The nanoparticles include c 11 BN particles, The second object includes c 11 BN particles, c 11 At least one of the BN plate and the Ag plate The thermal radiation conditioning system has at least two of the c 11 BN particles, or at least one c 11 BN particles and a c 11 BN plate, or at least two Ag plates.

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