Investigation of the effects of surface wettability and surface roughness on nanoscale boiling process using molecular dynamics simulation

The nanoscale liquid-vapor phase change process of argon above solid copper substrates with different surface wettability and surface roughness are studied with the help of nonequilibrium molecular dynamics simulations. The contact angles of an argon droplet on the copper solid substrate with different potential parameters are determined by the circle fitting function. With a constant temperature thermostat applied on the solid substrate, the liquid argon atoms absorbed energy. It was found that the increase of argon wettability on solid copper surfaces could enhance the heat transfer between the solid and fluid atoms and also the evaporation mass flux of liquid argon. The bubble nucleation time was advanced as well by the increased wettability. Moreover, the effect surface roughness generated using a multivariable Weierstrass-Mandelbrot function on the nanoscale boiling process was also investigated. The rough structures on the substrate could further advance the boiling inception and increase the evaporation rate. The energy transfer between the solid and fluid atoms become more efficient with the surface rough textures.