Heat Transfer at Aluminum-Water Interfaces: Effect of Surface Roughness

In this paper, we studied the effect of microscopic surface roughness on heat transfer between aluminum and water by molecular dynamic (MD) simulations and macroscopic surface roughness on heat transfer between aluminum and water by finite element (FE) method. It was observed that as the microscopic scale surface roughness increased, the thermal boundary conductance increased. The thermal conductance increases 20% when the ratio of the amplitude of the surface roughness to the width of the system was changed from 0 to 1. At the macroscopic scale, different degrees of surface roughness were studied by finite element method. The heat transfer was observed to enhance as the surface roughness increases. The surface roughness was found to enhance the heat transfer both at the microscopic scale and at the macroscopic scale. Based upon the calculations at the microscopic scale by MD simulations and at the macroscopic scale by Finite Element method, a procedure was proposed to obtain the thermal conductance of surface roughness at the length scale of macroscopic and able to include the macroscopic scale surface roughness.