The vibrational contribution to the thermal conductivity of a polyatomic fluid

Abstract

A simple analytical expression is proposed in this article to calculate the vibrational contribution to the thermal conductivity of a polyatomic fluid. The analytic expression was obtained based on the assumption that the self-diffusion process is the major mechanism in the transport of vibrational energy. The proposed expression is validated by comparing the thermal conductivity of CO₂ calculated by molecular dynamics (MD) simulations to experimental data over a wide range of temperature and pressure. It is also demonstrated that the proposed analytic expression greatly increases the accuracy of calculated thermal conductivity for CO₂ at the supercritical state.

Keywords:

• thermal conductivity
• vibrational contribution
• molecular dynamics

Acknowledgement

This work was supported by Office of Naval Research through the Multidisciplinary University Research Initiative (MURI) program, Award No. N00014-05-1-0432.