Definition of frame-invariant Soret coefficients for ternary mixtures

2018/10/25 by José M. Ortiz de Zárate, de Zárate, José M. Ortiz
Engineering · Environmental Science · #Chemical Physics (physics.chem-ph) #Environmental and Industrial Safety #FOS: Physical sciences #Field-Flow Fractionation Techniques #Fluid Dynamics (physics.flu-dyn) #Mining and Gasification Technologies #Soft Condensed Matter (cond-mat.soft)

paper · pdf · doi:10.48550/arxiv.1810.10921

openalex publication_date 2018/10/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

The definition of the Soret coefficient of a binary mixture includes a concentration prefactor, x(1-x) when mol fraction x is used, or w(1-w) when mass fraction w is used. In this paper the physical reasons behind this choice are reviewed, emphasizing that the use of these prefactors makes the Soret coefficient invariant upon change in the reference frame, either mass or molar. Then, it is shown how this invariance property can be extended to ternary mixtures by using an appropriate concentration prefactor in matrix form. The work is completed with some considerations of general non-isothermal diffusion fluxes, binary limits of the concentration triangle, selection of the dependent concentration in a ternary mixture, use of molar concentrations and, finally, extension to multi-component mixtures.

Related

• The Measurement of Soret and Thermodiffusion Coefficients in Binary and Ternary Liquid Mixtures
• A multiscale thermodynamic generalization of Maxwell-Stefan diffusion equations and of the dusty gas model
• The role of the molecular association in the change of the sign of the Soret coefficient in aqueous mixtures
• A new thermodynamic function for binary mixtures: the co-molar volume
• Effects of attractive inter-particle interaction on cross-transport coefficient between mass and heat in binary fluids