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6 added 88 characters in body
Chemomechanics
Possibly. Implicit in your question is the assumption that radiative heat transfer is playing or could play an important role in your configuration (vs. convection). If so, then applying a black"black" coating (and thus increasing the emissivity to essentially 1, with the caveat that we're talking about the maximum wavelengths of emission at 70°C) could benefit you. However, note that the coating itself may hinder heat transfer across various interfaces.
I would plug the relevant numbers into the various formulas for heat transfer ($hA_\mathrm{surface}(T-T_\infty)$ for convection, $kA_\mathrm{cross\,section}\Delta T/\Delta x$ for conduction, $\sigma\epsilon A_\mathrm{surface\,facing\,surroundings}(T^4-T^4_\infty)$ for radiation, as described in any introductory heat transfer textbook and at many locations online) to estimate the relative magnitude of convection vs. radiation before attempting to optimize a heat transfer mechanism that might be unimportant.
As an example, the natural convection coefficient $h$ can be very broadly estimated to around $10\,\mathrm{W}\,\mathrm{m}^{-2}\,\mathrm{K}^{-1}$ by order of magnitude (I'm sure exceptions exist in certain geometries). From the numbers you've given, one can estimate that changing the emissivity from 0 to 1 (by anodizing the aluminum, for instance) could potentially boost the outgoing heat flux by a detectable amount, but probably less than 100%. Furthermore, as other posters have noted, you may have other options to increase the outgoing heat flux much more substantially—using fins or a fan, perhaps.
Possibly. Implicit in your question is the assumption that radiative heat transfer is playing or could play an important role in your configuration (vs. convection). If so, then applying a black coating (and thus increasing the emissivity to essentially 1) could benefit you. However, note that the coating itself may hinder heat transfer across various interfaces.
Possibly. Implicit in your question is the assumption that radiative heat transfer is playing or could play an important role in your configuration (vs. convection). If so, then applying a "black" coating (and thus increasing the emissivity to essentially 1, with the caveat that we're talking about the maximum wavelengths of emission at 70°C) could benefit you. However, note that the coating itself may hinder heat transfer across various interfaces.
I would plug the relevant numbers into the various formulaeformulas for heat transfer ($hA_\mathrm{surface}(T-T_\infty)$ for convection, $kA_\mathrm{cross\,section}\Delta T/\Delta x$ for conduction, $\sigma\epsilon A_\mathrm{surface\,facing\,surroundings}(T^4-T^4_\infty)$ for radiation, as described in any introductory heat transfer textbook and at many locations online) to estimate the relative magnitude of convection vs. radiation before attempting to optimize a heat transfer mechanism that might be unimportant.
As an example, the natural convection coefficient $h$ can be very broadly estimated to around $10\,\mathrm{W}\,\mathrm{m}^{-2}\,\mathrm{K}^{-1}$ by order of magnitude (I'm sure exceptions exist in certain geometries). From the numbers you've given, one can estimate that changing the emissivity from 0 to 1 (by anodizing the aluminum, for instance) could potentially boost the outgoing heat flux by a detectable amount, but probably less than 100%. AsFurthermore, as other posters have noted, however, you may have other options to increase the outgoing heat flux much more substantially—using fins or a fan, perhaps.
I would plug the relevant numbers into the various formulae for heat transfer ($hA_\mathrm{surface}(T-T_\infty)$ for convection, $kA_\mathrm{cross\,section}\Delta T/\Delta x$ for conduction, $\sigma\epsilon A_\mathrm{surface\,facing\,surroundings}(T^4-T^4_\infty)$ for radiation, as described in any introductory heat transfer textbook and at many locations online) to estimate the relative magnitude of convection vs. radiation before attempting to optimize a heat transfer mechanism that might be unimportant.
As an example, the natural convection coefficient $h$ can be very broadly estimated to around $10\,\mathrm{W}\,\mathrm{m}^{-2}\,\mathrm{K}^{-1}$ by order of magnitude (I'm sure exceptions exist in certain geometries). From the numbers you've given, one can estimate that changing the emissivity from 0 to 1 (by anodizing the aluminum, for instance) could potentially boost the outgoing heat flux by detectable amount. As other posters have noted, however, you may have other options to increase the outgoing heat flux much more substantially—using fins or a fan, perhaps.
4 Clarifying type of surface