Generalization of experimental data regarding the thermal conductivity of gas mixtures from the structural point of view

Methods for the analytic determination of the effective conductivities of heterogeneous systems

“…In a number of studies [6,[39][40][41][42][43] attempts were made to extract information for the closure of Eq. ( 5) from experimental data.…”

“…( 5) from experimental data. In this case one or two experimental parameters, k 0 and n, were introduced into the expression for A in order to describe the effective thermal conductivity for at least one class of materials [39][40][41][42][43]. The reason for this is that N depends on many parameters (porosity, dimensions of the pores, temperature, pressure of the filler gas, contact conductivity between granules, etc.…”

“…However, the above-mentioned studies are sufficient to draw some conclusions concerning this group of methods. If we completely ignore the structural properties of the material, as was done in [6,[39][40][41], then this line of investigation, in our opinion, is not very promising, for the reasons indicated above. Much more informative and better justified are those semiempirical methods in which in determining A we take account of the topology of the heterogeneous system and empirical coefficients are used only to make some individual features of the process more precise [42,43].…”