Molecular Dynamics Simulations of the Effects of Surface Sinusoidal Nanostructures on Nanoscale Liquid Film Phase-Change
Q Cao and Z Cui, JOURNAL OF THERMAL SCIENCE, 29, 1076-1084 (2020).
Nanostructures on heat transfer surfaces can enhance micro/nanoscale phase-change heat transfer processes. To understand the enhancement mechanisms provided by nanostructures, evaporation processes of nanoscale liquid films on periodic sinusoidal-shaped surfaces were investigated via molecular dynamics simulations. By changing the amplitudes (A) and periods (T) of the curves describing the sinusoidal shapes, which possess shapes similar toj(x)=h(0)+Asin(2 pi x/T), sinusoidal surfaces of different sizes were constructed. An unevaporated region always existed on the copper plate for all surfaces during phase- change processes. Moreover, we calculated the interfacial thermal resistances and the mismatches between the vibrational density of states of the solid and liquid for different surfaces. The results show that the argon temperature changes and evaporation rates during the phase- change process on sinusoidal surfaces are higher than those on flat surfaces, and these results increase with the increase in amplitudes and the decrease in periods within certain limits mainly because of the thermal resistance decrease at the solid-liquid interface. Furthermore, the corresponding mismatches between the vibrational density of states of the solid and liquid also decrease, which indicates that the existence of sinusoidal nanostructures enhances the heat transfer of the phase-change process.
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