Programme

P.41 -- Poster, VCTP-44

Date: Tuesday, 30 July 2019

Time: 08:30 - 10:00

A model to predict the thermal diffusion factors in binary mixtures

Tu Khai Nam Nguyen (1), Hai Hoang (2), Guillaume Galliero (3)

(1) Ho Chi Minh University of science, 227 Nguyen Van Cu, District 5, Ho Chi Minh City 7000, Vietnam (2) Institute of Fundamental and Applied Sciences, Duy Tan University, 10C Tran Nhat Duat Street, District 1, Ho Chi Minh City 700000, Viet Nam (3)Laboratoire des Fluides Complexes et leurs Réservoirs UMR5150 CNRS-TOTAL-UPPA, Université de Pau et des Pays de l’Adour, Pau, France

Development of models to predict thermal diffusion factor, or Soret coefficient, of binary fluid mixtures has been the objective of many works in the past [1]. However, the prediction capabilities of the available models are often limited, even for simple binary mixtures, if a large range of thermodynamic conditions is considered. Thus, this work aims at providing a generic model able to quantitatively provide thermal diffusion factors of simple binary mixtures over a wide range of thermodynamic conditions (gas, supercritical and liquid). The proposed model stems from the fact that direct residual transport properties of simple fluids are strongly linked to their so called excess entropy [2,3]. Taking advantage of this link, the model decomposes the thermal diffusion factor into zero-density and residual contributions, in which the former, dominant in gas phases, is computed from the kinetic theory. The latter contribution, dominant in dense phases, is further separated into isotopic and configurational contributions which are both functions of the excess entropy of the two considered species. First, it will be shown that the functional form of the proposed model is fully supported by results coming from molecular dynamics simulations of simple fluids mixtures (e.g. Ar + Kr). Second, the model has been combined with excess entropies deduced from modern equations of states [4] so as to check its ability to predict thermal diffusion factors of various binary mixtures such as those composed of n-alkanes.

Presenter: Nguyen Tu Khai Nam