Molecular Dynamics Study on Bubble Behaviors on a Grooved Surface with Different Roughnesses and Wetting Conditions

Molecular dynamics (MD) simulations are conducted to investigate bubble nucleation, growth, coalescence, and departure dynamics in water on heated sinusoidally grooved surfaces. The goal is to decipher the nanoscale effects of the surface roughness and wettability on bubble dynamics. Under an identical wettability, an increasing surface roughness reduces bubble characteristic times (nucleation, growth, and departure), with density profiles revealing that rougher surfaces generate more efficient nucleation sites. Additionally, at a fixed roughness, hydrophilic surfaces exhibit significantly shorter bubble characteristic times than hydrophobic ones, attributed to lower Kapitza resistance and enhanced solid-liquid heat transfer. The results demonstrate that simultaneous enhancement of surface roughness and hydrophilicity synergistically accelerates bubble generation. These findings offer mechanistic insights and practical guidance for optimizing nucleate boiling performance in engineering applications such as heat exchangers and electronic cooling systems.