Near-Field Radiative Heat Transfer under Temperature Gradients and Conductive Transfer

Abstract

Abstract:We describe a recently developed formulation of coupled conductive and radiative heat transfer (RHT) between objects separated by nanometric, vacuum gaps. Our results rely on analytical formulas of RHT between planar slabs (based on the scattering-matrix method) as well as a general formulation of RHT between arbitrarily shaped bodies (based on the fluctuating-volume current method), which fully captures the existence of temperature inhomogeneities. In particular, the impact of RHT on conduction, and vice versa, is obtained via self-consistent solutions of the Fourier heat equation and Maxwell's equations. We show that in materials with low thermal conductivities (e.g. zinc oxides and glasses), the interplay of conduction and RHT can strongly modify heat exchange, exemplified for instance by the presence of large temperature gradients and saturating flux rates at short (nanometric) distances. More generally, we show that the ability to tailor the temperature distribution of an object can modify the behaviour of RHT with respect to gap separations, e.g. qualitatively changing the asymptotic scaling at short separations from quadratic to linear or logarithmic. Our results could be relevant to the interpretation of both past and future experimental measurements of RHT at nanometric distances.

Polyethylene glycol with dual three-dimensional porous carbon nanotube/diamond: a high thermal conductivity of composite PCM

“…As a result, the phonons are the dominant heat carriers in CDF/ PEG. However, the heat transfer of pure PEG (0.28 W•m −1 •K −1 ) was a random process, in which bring the temperature gradient [40]. Obviously, the heat transfer in CDF/PEG enhances the lattice vibration through the dual 3D-CDF skeleton and improves the PEG and DF/PEG thermal conductivity.…”

Conduction–Radiation Coupling between Two Distant Solids Interacting in a Near-Field Regime

“…Over the past several years we have performed a comprehensive study of the impact of this coupling [37][38][39][40][41][42][43], which is the topic of the present review paper. More specifically, we first studied this effect in the convenient geometry of two parallel slabs and in the diffusive regime, as discussed in Section 2.…”