Effects of attractive inter-particle interaction on cross-transport coefficient between mass and heat in binary fluids

ABSTRACTIn some binary fluids, mass transport is observed under a temperature gradient. This phenomenon is called the Soret effect. In this study, we discuss the influence of inter-particle interaction. We considered equimolar binary Lennard–Jones fluids with a mass contrast, whereas the interaction was common for all the particle pairs with various cut-off lengths. We performed molecular dynamics simulations of such fluids under equilibrium to obtain the cross-transport coefficients L1q between the fluxes of mass and heat. The simulation revealed that this quantity strongly depends on the cut-off length. Further, we decomposed the heat flux into kinetic and potential contributions and calculated the cross-correlations between decomposed fluxes and the mass flux. The result indicates that the potential contribution dominates L1q, implying that the Soret coefficient is altered by the inter-particle interaction.KEYWORDS: Soret effecttransport coefficientlinear response theorybinary fluidscut-off length AcknowledgmentsThe authors thank Prof. Sasa (Kyoto University) for informing the authors of his work on the derivation of hydrodynamic equations from the Hamiltonian dynamics.Disclosure statementNo potential conflict of interest was reported by the author(s).