TY - JOUR

T1 - Coherent regime and far-to-near-field transition for radiative heat transfer

AU - Tsurimaki, Yoichiro

AU - Chapuis, Pierre Olivier

AU - Okajima, Junnosuke

AU - Komiya, Atsuki

AU - Maruyama, Shigenao

AU - Vaillon, Rodolphe

PY - 2017/1/1

Y1 - 2017/1/1

N2 - Radiative heat transfer between two semi-infinite parallel media is analyzed in the transition zone between the near-field and the classical macroscopic, i.e. incoherent far-field, regimes of thermal radiation, first for model gray materials and then for real metallic (Al) and dielectric (SiC) materials. The presence of a minimum in the flux-distance curve is observed for the propagative component of the radiative heat transfer coefficient, and in some cases for the total coefficient, i.e. the sum of the propagative and evanescent components. At best this reduction can reach 15% below the far-field limit in the case of aluminum. The far-to-near-field regime taking place for the distance range between the near-field and the classical macroscopic regime involves a coherent far-field regime. One of its limits can be practically defined by the distance at which the incoherent far-field regime breaks down. This separation distance below which the standard theory of incoherent thermal radiation cannot be applied anymore is found to be larger than the usual estimate based on Wien׳s law and varies as a function of temperature. The aforementioned effects are due to coherence, which is present despite the broadband spectral nature of thermal radiation, and has a stronger impact for reflective materials.

AB - Radiative heat transfer between two semi-infinite parallel media is analyzed in the transition zone between the near-field and the classical macroscopic, i.e. incoherent far-field, regimes of thermal radiation, first for model gray materials and then for real metallic (Al) and dielectric (SiC) materials. The presence of a minimum in the flux-distance curve is observed for the propagative component of the radiative heat transfer coefficient, and in some cases for the total coefficient, i.e. the sum of the propagative and evanescent components. At best this reduction can reach 15% below the far-field limit in the case of aluminum. The far-to-near-field regime taking place for the distance range between the near-field and the classical macroscopic regime involves a coherent far-field regime. One of its limits can be practically defined by the distance at which the incoherent far-field regime breaks down. This separation distance below which the standard theory of incoherent thermal radiation cannot be applied anymore is found to be larger than the usual estimate based on Wien׳s law and varies as a function of temperature. The aforementioned effects are due to coherence, which is present despite the broadband spectral nature of thermal radiation, and has a stronger impact for reflective materials.

KW - Coherent regime

KW - Far field

KW - Interferences

KW - Near field

UR - http://www.scopus.com/inward/record.url?scp=84994036885&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84994036885&partnerID=8YFLogxK

U2 - 10.1016/j.jqsrt.2016.08.006

DO - 10.1016/j.jqsrt.2016.08.006

M3 - Article

AN - SCOPUS:84994036885

VL - 187

SP - 310

EP - 321

JO - Journal of Quantitative Spectroscopy and Radiative Transfer

JF - Journal of Quantitative Spectroscopy and Radiative Transfer

SN - 0022-4073

ER -