Nanoscale Thermal Behavior and Phase Transition of Nano-Enhanced Phase Change Materials in Ribbed Channels: A Molecular Dynamics Study

Abstract

Ribbed channel geometries are widely recognized for their ability to modify flow structures and influence thermal transport. In this study, the nanoscale thermal behavior of nano-enhanced phase change materials (NePCMs) confined within a ribbed nanochannel was investigated using molecular dynamics simulations. The model consisted of a confined domain (50 × 150 × 50 Å3) with non-connected rotating ribs, and the effect of rib number (1–4) on atomic-level structural and thermal properties was systematically analyzed over a 10 ns simulation period. The results show that increasing the number of ribs altered local atomic arrangements, enhanced fluid–structure interactions, and intensified velocity fluctuations within the confined region. These effects led to measurable, statistically significant improvements in thermal transport. Specifically, heat flux increased from 5.19 ± 0.02 to 5.54 ± 0.01 W/m2 (approximately 6.7%), while thermal conductivity increased from 0.65 ± 0.01 to 0.72 ± 0.02 W/m·K (approximately 10.8%) as the rib number increased from 1 to 4. In addition, the phase transition time was slightly reduced, indicating faster energy absorption and release dynamics under enhanced mixing and interfacial interaction conditions. It should be noted that the findings provide atomistic-level insight into how internal geometric features influence heat transfer and phase transition mechanisms. These results contribute to the fundamental understanding of nanoscale transport phenomena and may inform future multiscale design strategies for advanced thermal management systems.