Complexity matters: Highly-accurate numerical models of coupled radiative–conductive heat transfer in a laser flash experiment

Response to “Comment on “High‐Temperature Thermal Transport in Porous Silica Materials: Direct Observation of a Switch from Conduction to Radiation””

“…Lunev outlines in his response an additional model that directly couples conductive and radiative heat transport (equation 2) that he has published. [3] This model seems suitable for analyzing the radiation-conduction transition that we reported in our paper. Applying this model qualitatively reproduces the time-dependent features of a hollow sphere sample (d = 882 nm, t = 31 nm).…”

Digital twin of a laser flash experiment helps to assess the thermal performance of metal foams

“…In the flash method, akin to other methods of measuring the diffusion coefficients [7], the parameters need to be determined by solving an "inverse problem". The latter starts with an initial hypothesis on thermal transfer mechanisms (usually, conduction, but also coupled conduction and radiation [8]), evaluating a model solution comparable to the experimental signal, and iteratively changing the model parameters to achieve a good fit to the data. The essence of the method consists in using the temperature history of a sample, which spans over just a few hundred milliseconds for a typical millimetre-thick medium-conductive sample, to infer the thermal behavior of large installations (e.g.…”

Comment on “High‐Temperature Thermal Transport in Porous Silica Materials: Direct Observation of a Switch from Conduction to Radiation”

“…The interested reader is referred to ref. [12] for a more detailed description of the RTE and its solutions.…”

“…If radiation transfer is assumed to occur in a vacuum between two parallel plates (flat grey boundaries), the latter should be equal to η = 1/(2 − ε). [12] The "transparent" model is derived from Equation ( 1) where the factor η Bi is replaced with just η.…”

“…A different approach based on the direct coupling between a heat equation and a radiative transfer equation was previously described in ref. [12]. This is largely inspired by the pioneering works of Andre and Degiovanni [18,19] and Lazard et al [20,21] The boundary problem solved therein is:…”