A molecular dynamics simulation study on the thermal conductivity of a supercritical carbon dioxide-nitrogen mixture

In this computational study, molecular dynamics (MD) simulation is utilized to calculate the thermal conductivity of carbon dioxide with nitrogen under supercritical conditions. The large-scale atomic/molecular massively parallel simulator (LAMMPS) software was utilized, along with the transferable potentials for phase equilibria (TraPPE) and the Galassi-Tildesley (GT) force fields, to accurately model the atomic structures of carbon dioxide and nitrogen within the simulation box. The simulation encompassed molar concentrations of nitrogen ranging from 1 % to 3 %, with pressures up to 100 bar and temperatures between 30 °C to 50 °C. In order to verify the precision of the simulation, the thermal conductivity of pure CO₂ and a mixture of CO₂ and N₂ were assessed by comparing them with data from the NIST database as well as experimental data. Remarkably, the simulation findings exhibited excellent agreement with the experimental data and the NIST database, showcasing average absolute errors ranging from 6 % to 11 % for pure CO₂ and 6 % to 15 % for the CO₂/N₂ mixture.