Unraveling regimes of solid–liquid interfacial heat transfer from nanoscale to microscale

Abstract

Nonequilibrium molecular dynamics simulations were carried out to explore the Kapitza length at hydrophilic and hydrophobic Pt–Ar and Si–H2O interfaces under constant heat flux or overall temperature difference. The liquid films with thicknesses ranging from 0.392 nm to 1082 nm were sandwiched between two solid walls. Under constant heat flux, Kapitza length remained approximately constant. However, under constant overall temperature differences, the heat flux across nanoscale liquid film was three orders of magnitude greater than that across microscale liquid film. Moreover, Kapitza length was comparable in magnitude to the liquid film thickness, indicating that heat flux is a significant determinant of Kapitza length. Notably, a giant Kapitza length of 1382 nm was found at a hydrophobic solid–liquid interface with a 1082 nm thick liquid film. Our results identified three primary regimes: phononic, transition, and conductive regimes in the scale dependence of Kapitza length on liquid film thickness.

Wentao Chen

Research Fellow

My research interests include near-field heat transfer, thermal transport at the solid-solid and solid-liquid interface, and molecular dynamics simulation.