An important question in turbulent Rayleigh-B'{e}nard convection (RBC) is the effectiveness of convective heat transport, which is conveniently described via the scaling of the Nusselt number (${\rm{Nu}}$) with the Rayleigh (${\rm{Ra}}$) and Prandtl (${\rm{Pr}}$) numbers. In RBC experiments, the heat supplied to the bottom plate is also partly transferred by thermal radiation. This heat transport channel, acting in parallel with the convective and conductive heat transport channels, is usually considered insignificant and thus neglected. Here we present a detailed analysis of conventional far-field as well as strongly enhanced near-field radiative heat transport occurring in various RBC experiments. A careful inclusion of the radiative transport appreciably changes the ${\rm{Nu}}={\rm{Nu}}({\rm{Ra}})$ scaling inferred in turbulent RBC experiments near ambient temperature utilizing gaseous nitrogen and sulphur hexafluoride as working fluids. On the other hand, neither the conventional far-field radiation nor the strongly enhanced near-field radiative heat transport appreciably affects the heat transport law deduced in cryogenic helium RBC experiments.

中文翻译：

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Rayleigh-Bénard对流实验中的热辐射

对流瑞利-B'{e} nard对流（RBC）的一个重要问题是对流传热的有效性，这可以通过使用瑞利对Nusselt数（$ {\ rm {Nu}} $）进行缩放来方便地描述。（$ {\ rm {Ra}} $）和Prandtl（$ {\ rm {Pr}} $）数字。在RBC实验中，提供给底板的热量也通过热辐射部分转移。与对流和传导热传递通道平行作用的该热传递通道通常被认为是无关紧要的，因此被忽略了。在这里，我们介绍了常规的远场以及在各种RBC实验中发生的强增强的近场辐射热传输的详细分析。仔细考虑辐射传输会明显改变$ {\ rm {Nu}} = {\ rm {Nu}}（{\ rm {Ra}}）$在室温下，利用气态氮和六氟化硫作为工作流体，在湍流RBC实验中推断出了结垢。另一方面，常规的远场辐射或强烈增强的近场辐射热传输都不会明显影响低温氦RBC实验中推导的热传输规律。