Abstract: The nucleation process in hexadecane/super critical carbon dioxide solution was investigated. The full-atom molecular dynamics model was employed and run in isothermal-isobaric ensemble where the number of particles, pressure, and temperature of the system were in equilibrium. An exp-6 field was employed to describe the force field and a distance-based method was proposed to identify nuclei. A series of snapshots were presented to trace the process of bubble nucleation. It showed that low-density nuclei were formed when the pressure of the hexadecane and carbon dioxide saturated system was reduced. Then, carbon dioxide molecules would continue to enter into the gas phase until a bubble with a large number of gas molecules was formed.

Key words: hexadecane, supercritical carbon dioxide, bubble nucleation, molecular simulation, phase change