On the increased heat conduction and changed flow boundary-layer of nanofluids by molecular dynamics simulation

The present work is intended to reveal the microscopic physical essence of nanofluid convective heat transfer enhancement. Based on the idea that the improved convective heat transfer performance with nanofluids is caused by their increased heat conduction and changed flow boundary-layer, the present work performs molecular dynamics (MD) simulations with nanofluids from two aspects, including: heat conduction and boundary layer flow. MD simulation models for heat conduction and boundary layer flow are created separately. Thermal conductivity of water-based nanofluids is calculated by MD method and temperature effect for nanofluid thermal conductivity is discussed. Furthermore, influence of temperature for the absorption layer and micro-motions of nanoparticles have been examined. Flow behaviors of laminar sub-layer with nanofluids are studied. It is found that micro-motions of nanoparticles completely change the flow behavior of nanofluids, destroy the flow boundary layer, and therefore make heat conduction through laminar sub-layer easier. The results reported in this work provide direct evidence for explaining convective heat transfer enhancement in nanofluids.