Molecular Dynamics Simulation of Heat-Conducting Near-Critical Fluids

TL;DR

This study uses molecular dynamics simulations to analyze heat conduction in near-critical supercritical fluids, revealing critical behavior of thermal conductivity and fluid cluster dynamics under temperature gradients.

Contribution

It provides detailed simulation data on critical singularities and flux distributions in near-critical fluids, confirming theoretical predictions.

Findings

Thermal conductivity shows critical divergence near the critical point.

Liquid-like clusters move toward warmer regions, gas-like clusters toward cooler regions.

Critical enhancement of thermal conductivity due to counterflow of fluid clusters.

Abstract

Using molecular dynamics simulations, we study supercritical fluids near the gas-liquid critical point under heat flow in two dimensions. We calculate the steady-state temperature and density profiles. The resultant thermal conductivity exhibits critical singularity in agreement with the mode-coupling theory in two dimensions. We also calculate distributions of the momentum and heat fluxes at fixed density. They indicate that liquid-like (entropy-poor) clusters move toward the warmer boundary and gas-like (entropy-rich) regions move toward the cooler boundary in a temperature gradient. This counterflow results in critical enhancement of the thermal conductivity.