A study on thermodynamic and transport properties of carbon dioxide using molecular dynamics simulation

Molecular dynamics simulation was applied to test and evaluate the ability of several models of carbon dioxide on predicting thermodynamics and transport properties. Firstly, we compared the liquid-vapor coexist curves of seven kinds of carbon dioxide models by molecular dynamics simulations. It was found that the Cygan_flex model and EPM2 model were more accurate than the others. Then we investigated the structural properties of carbon dioxide using NPT ensemble molecular dynamics simulation. The fluid became less dense with the increasing temperature. Thirdly, the self-diffusion coefficients were studied at temperature and pressure up to 600 K and 80 MPa, respectively. The results showed that the self-diffusion coefficient decreased with the increasing pressure and increased with increasing temperature. Finally, we calculated the thermal conductivity of carbon dioxide at 250 K using EPM2_flex model, Cygan_flex model and TraPPE_flex model. So, we should pay attention to the selection of appropriate carbon dioxide models to obtain different carbon dioxide properties.