On the temperature and pressure dependences of the effective thermal conductivity of granites

Abstract

The results of experimental measurements of the temperature dependence of the effective thermal conductivity of various granite samples obtained by the absolute stationary method in the temperature and pressure ranges of 273- 523 K and 0.1-400 MPa, respectively, are analyzed. The power-law character of the temperature dependence of the effective thermal conductivity for all measured granite samples at atmospheric pressure is established. We have shown that pressure significantly affects the power law of the temperature dependence of the effective thermal conductivity of granite samples. A low-parameter description of the temperature-pressure behavior of thermal conductivity is proposed. A correlation is established between its components.

Temperature-baric behavior of the effective thermal conductivity of sandstones

“…Thus, the data presented in Table 1 are sufficient to calculate the effective thermal conductivity for the presented samples in a wide temperature-baric range. Indeed, substituting α and * 0 P in equations ( 5) and ( 6) we can calculate ) (P It should be noted that, in contrast to the data for granites given in [8], for sandstones, we can not determine a single value * 0…”

“…is often close to linear, but for complex multicomponent structures, which include sedimentary rocks, this dependence is highly nonlinear especially in the initial section. At the same time, in the range of pressure from atmospheric to several hundred MPa (the most interesting in geological applications), it can be fairly well estimated by empirical and semiempirical two-component dependences ( [7,8] and references therein), in particular:…”

“…It causes a weakening of phonon scattering of heat waves, which, together with the influence of block boundaries and crystal lattice defects, has a rather complex IOP Publishing doi:10.1088/1755-1315/1021/1/012079 2 nature of the temperature dependence of effective thermal conductivity [6]. Nevertheless, the analysis of many experimental and theoretical works ( [7,8] and references therein) shows that the temperature dependence of the effective thermal conductivity of a large class of compounds and, first of all, rocks is well described by the power law:…”