Measurement of Near-Field Thermal Radiation Between Two Closely-Spaced Glass Plates

2008 ◽  
Author(s):  
Lu Hu ◽  
Arvind Narayanaswamy ◽  
Xiaoyuan Chen ◽  
Gang Chen
Keyword(s):  
Heat Flux ◽  
Electromagnetic Waves ◽  
Radiative Heat ◽  
Thermal Emission ◽  
Near Field ◽  
Current Source ◽  
Radiative Heat Flux ◽  
Photon Tunneling ◽  
Field Radiation ◽  
Planck’S Law

At a finite temperature, electrons and ions in any matter are under constant thermal agitation, acting as the random current source for thermal emission. The thermally-excited electromagnetic waves have two forms: the propagating modes that can leave the surface of the emitter and radiate freely into the space, and the non-propagating modes (evanescent modes) that do not radiate. The contribution from the propagating modes, or the far-field radiation modes, to the radiative heat flux is well-known and its maximum is governed by Planck’s law of blackbody radiation. The non-propagating modes do not propagate and thus do not carry energy in the direction normal to the surface, unless a second surface is brought close to the first to enable photon tunneling. The contribution from the non-propagating modes to radiative heat flux is the near-field radiative flux.

Near-Field Radiative Heat Transfer Between Two α-MoO3 Biaxial Crystals

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Xiaohu Wu ◽  
Ceji Fu ◽  
Zhuomin M. Zhang
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Radiative Heat Transfer ◽  
Radiative Heat ◽  
Hexagonal Boron Nitride ◽  
Near Field ◽  
Radiative Heat Flux ◽  
Relative Rotation ◽  
Maximum Heat ◽  
Phonon Polaritons

Abstract The near-field radiative heat transfer (NFRHT) between two semi-infinite α-MoO3 biaxial crystals is investigated numerically based on the fluctuation–dissipation theorem combined with the modified 4 × 4 transfer matrix method in this paper. In the calculations, the near-field radiative heat flux (NFRHF) along each of the crystalline directions of α-MoO3 is obtained by controlling the orientation of the biaxial crystals. The results show that much larger heat flux than that between two semi-infinite hexagonal boron nitride can be achieved in the near-field regime, and the maximum heat flux is along the [001] crystalline direction. The mechanisms for the large radiative heat flux are explained as due to existence of hyperbolic phonon polaritons (HPPs) inside α-MoO3 and excitation of hyperbolic surface phonon polaritons (HSPhPs) at the vacuum/α-MoO3 interfaces. The effect of relative rotation between the emitter and the receiver on the heat flux is also investigated. It is found that the heat flux varies significantly with the relative rotation angle. The modulation contrast can be as large as two when the heat flux is along the [010] direction. We attribute the large modulation contrast mainly to the misalignment of HSPhPs and HPPs between the emitter and the receiver. Hence, the results obtained in this work may provide a promising way for manipulating near-field radiative heat transfer between anisotropic materials.

Near-Field Radiative Heat Transfer Between Materials With Dielectric Coatings

2008 ◽  
Author(s):  
Ceji Fu ◽  
Wenchang Tan
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Coating Thickness ◽  
Radiative Heat Transfer ◽  
Radiative Heat ◽  
Near Field ◽  
Dielectric Coating ◽  
Radiative Heat Flux ◽  
Surface Polaritons ◽  
Dielectric Coatings

Radiative heat transfer between materials with dielectric coatings is numerically studied based on the fluctuational electrodynamics and the fluctuation-dissipation theorem. The results show that whereas a dielectric coating (SiC) enhances the far-field radiative heat transfer between two bulk metals, it will suppress the radiative heat transfer in the near-field and the suppression is only for the s-wave contribution. The total radiative heat flux continuously decreases as the coating thickness increases up to 1 μm. A further increase in the coating thickness will cause the total radiative heat flux to increase slightly before it saturates. In addition, a much smaller coating thickness than the coating’s skin depth is enough to significantly change the total radiative heat flux in the near-field region. On the contrary, a thin dielectric coating that supports surface polaritons can greatly enhance the radiative heat transfer between a metal and a dielectric in the case that the coating is on the metal. The large enhancement is due to surface polaritons excited on the two surfaces of the air gap boundaries.

Nonequilibrium radiative heat flux modeling for the Huygens entry probe

2006 ◽  
Vol 111 (E7) ◽  
Author(s):  
T. E. Magin ◽  
L. Caillault ◽  
A. Bourdon ◽  
C. O. Laux
Keyword(s):  
Heat Flux ◽  
Radiative Heat ◽  
Radiative Heat Flux ◽  
Entry Probe

Handling of Collimated Irradiation on a Plane-Parallel Participating Medium

2000 ◽  
Author(s):  
Christian Proulx ◽  
Daniel R. Rousse ◽  
Rodolphe Vaillon ◽  
Jean-François Sacadura
Keyword(s):  
Heat Flux ◽  
Monte Carlo ◽  
Monte Carlo Method ◽  
Radiative Heat ◽  
Radiative Heat Flux ◽  
Scattering Media ◽  
One Dimensional ◽  
Plane Parallel ◽  
Collimated Beam ◽  
Good Agreement

Abstract This article presents selected results of a study comparing two procedures for the treatment of collimated irradiation impinging on one boundary of a participating one-dimensional plane-parallel medium. These procedures are implemented in a CVFEM used to calculate the radiative heat flux and source. Both isotropically and anisotropically scattering media are considered. The results presented show that both procedures provide results in good agreement with those obtained using a Monte Carlo method, when the collimated beam impinges normally.

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