A molecular dynamics study on thermophysical and transport properties of fluorinated alkane liquids

Thermophysical and transport properties of heat media, which are extensively utilized in heat transfer devices such as refrigerating and air-conditioning equipment, are inherently determined from microscopic components like molecular interactions and molecular-scale structure of liquid. An essential understanding of these microscopic information are of critical importance for designing and exploring liquid materials having desired properties. Here we performed molecular dynamics (MD) simulation on fluorocarbon liquids, which are prevailing as typical coolants in industrial products, in order to examine thermophysical properties such as a liquid-vapor phase change property and thermal conductivity at the bulk liquid state. In the present study, we have developed a new transferable potential model for fluorocarbon and hydrofluorocarbons by modifying partial charges of the OPLS-AA force field based on the ab initio molecular orbital calculation. We demonstrated that our developed potential models well reproduce experimental data of a liquid-vapor phase change property and thermal conductivity for several fluorocarbons having different chain lengths. Not only physical property itself, but the underlying molecular-scale mechanism was also examined, i.e., the microscopic mechanism to realize the thermal conductivity was precisely investigated by decomposing macroscopic thermal conductivity into microscopic building blocks.