Effects of velocity on evaporation rate of nanoscale water droplets

The evaporation of nanoscale water droplets exhibits significant deviations from continuum-based predictions, posing challenges for accurate modeling. Yet, the accurate prediction of evaporation process can be crucial to many natural and engineering applications. This study employs molecular dynamics (MD) simulations to investigate the impact of air velocity on the evaporation dynamics of nano water droplets. Previous research demonstrated that evaporation rates of nanodroplets increase with both temperature and initial droplet size. However, these studies were mostly limited to stationary droplets. The work presented in this paper reveals a counter-intuitive decrease in evaporation rate with increasing air velocity. This study attributes and proves (through MD data analysis) that this phenomenon is due to the compressive forces exerted by moving air molecules, which reduce the kinetic energy of surface water molecules, thereby inhibiting evaporation. The findings underscore the importance of considering nanoscale effects in evaporation models and suggest potential applications in fields such as disease transmission, coating technology, and nanoscale drug delivery.