Molecular dynamics study of instantaneous interfacial thermal resistance of droplets on flat crystalline surface during cooling and ice formation

Condensation and frost formation degrade the heat transfer performance of air-conditioners and refrigerators. Yet, the frost formation mechanism has not been fully understood. In the present study, we numerically investigate nanoscale H₂O droplets during cooling and ice formation utilizing classical molecular dynamics simulations. The mW potential is employed for the H₂O molecules. A nanoscale H₂O droplet is placed on a flat solid wall consisting of Pt or Pb atoms. We examine where ice nucleation is formed and how the ice formation proceeds inside the droplet, and then evaluate the time change in instantaneous interfacial thermal resistance between the H₂O molecules and the solid wall. In common with Pt and Pb surfaces, the time changes in the instantaneous interfacial thermal resistance and the density depletion length are qualitatively consistent in the present transient thermal energy transfer process together with the phase change. In addition, the relation of the time-averaged instantaneous interfacial thermal resistance and the density depletion length are qualitatively consistent with the relation of the solid-liquid interfacial thermal resistance in the steady-state.