An Essay on the Heat of Transport in Solids and a Partial Guide to the Literature

Abstract

This article reviews the subject of the Soret effect and Thermodiffusion in solids more generally. In doing so it draws upon computer simulations made with a method (the Grout-Gillan method) derived from the Green-Kubo approach to transport coefficients in solids. The insights into the make-up of heats of transport parameters, Q*, so obtained are described and used to provide additional insight into measured heats of transport in situations where no reliable theories or simulations exist. These insights also point to the relations between heats of transport on the one hand and phonon thermal conductivity and focussed collision sequences on the other. These relations point to circumstances where the heat of transport may be small (e.g. low coordination in the lattice) or can be estimated from heats of activation for atom movements. In other cases the Grout-Gillan simulation method may offer the most reliable approach. These new insights are expected to be useful in materials modelling.

Depletion, Chemical Reaction and Transport in High Burnup Nuclear Fuel

“…While the relation in Eq. (9) can be treated as a partial molar enthalpy, the other term within the -∂ ∂ square brackets is just a ratio of two kinetic coefficients, usually termed the heat of transport , Lidiard, 2015, Sugisaki, Sato and Furuya, 1981. This parameter has not yet been shown to have a thermodynamic representation or a uniformly accepted theoretical basis except for the case of an ideal gas.…”

Coupled Mass and Heat Transport Models for Nuclear Fuels using Thermodynamic Calculations

“…The equation for coupled thermo-diffusion mass flux derived from equations ( 18) is usually given in the literature [18][19][20][21][22], as:…”

“…𝐽 " = −𝐿 "" ∇ 𝜇 " F − 𝑄 " * @ ∇𝑇 𝑇 ( 21 ) where the effect of thermal gradient on diffusion uses the concept of reduced (i.e., effective) heat of transport, 𝑄 " * @ , which has not been resolved experimentally or theoretically [19,23,24]. Some interpretations include dependencies on gradients of thermodynamic quantities which is not in line with the tenets of linear irreversible thermodynamics.…”