Molecular Dynamics Simulations of Nanoscale Heat Transfer in the Free Molecular Regime

TIMOTHY SIPKENS, National Research Council Canada

     Abstract Number: 247
     Working Group: Nanoparticles and Materials Synthesis

Abstract
Nanoscale conduction is a fundamental quantity relevant to some laser diagnostics for particles, energy storage by aerosols (e.g., iron–iron oxide nanoparticles), and gas sensors, among other applications. For small particles that make up many aerosols, conduction takes place in the free molecular (or transition, where modeling still requires knowledge of the free molecular) regime. Free molecular conduction between the particles and the surrounding gas is then quantified by the thermal accommodation coefficient (TAC), which marks the effectiveness of individual collisions between gas molecules and the particle surface. Molecular dynamics (MD) is a theoretical approach for examining these individual molecular collisions and computing the heat transfer across an ensemble of these collisions. This study uses the molecular dynamics method first introduced by Daun et al. (2009), which repeatedly scatters individual gas molecules, sampled from an equilibrium gas, from a small volume of surface material. This study examines the effect of interatomic potential on MD-derived TAC for a range of materials and phases. We also present TACs for new surfaces, such as metal oxides and amorphous carbon, with the objective of expanding our understanding of trends in the TAC for realistic surfaces.