Characterizing dynamic behavior of carbon dioxide nano-jets using molecular dynamics simulation

This paper reports on the use of molecular dynamics (MD) simulations to elucidate the dynamic behavior of CO2 through a Graphene/Au(111) nano-injector. We investigated the effects of jet diameter (d), system temperature (T), and the extrusion velocity (v) of a graphite piston plate on the jet pattern, system pressure (P), and the number of molecules (Nm) in the outflow. Simulation results show that the combined effects of high v and small d induced a larger jet angle, resulting in an increase in the number of CO2 molecules attached to the surface of the outlet. Increasing d enhanced the formation of the T-junction molecular geometry of CO2 molecules, due to the effects of electrostatic attraction between C (0.5888e) and O (− 0.2944e) of CO2, which caused the formation of larger agglomerations of CO2 molecules in the vicinity of the nano-injector orifice in the final extrusion stage. The increase in P within the cylinder of the nano-injector was more pronounced during middle and final stages of extrusion, compared with the effects observed during the initial stages. Despite the fact that Nm increased noticeably with an increase in T, the value of Nm at d = 1.5 nm and T ≥ 300 K greatly exceeded that at d = 1.0 nm and T = 500 K, regardless of the value of v. The numerical simulations presented in this study could be helpful in the design of nano-injectors for a diversity of applications associated with engineering systems and biomedicine at the nano-scale.