Systematic extension of a force field for fluorinated propenes to HCFO and longer-chained HFO compounds, and its application for studies on new working fluids

• Applicant: Professorin Dr.-Ing. Gabriele Raabe
• Subject Area: Technical Thermodynamics ; Technical Chemistry
• Term: from 2016 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 326429904

The aim of this project is the systematic extension of a force field for fluorinated propenes to hydrochlorofluoroolefines (HCFO) and hydrofluoroolefines (HFO) based on fluorinated butenes. It thereby emphasis on investigating the transferability of the Lennard-Jones (LJ) parameters for fluorine and chlorine atoms to derive a consistent set of LJ parameters that enables studies on different HFO/HCFO compounds with any number of bonded halogen atoms. Furthermore, the rotations about dihedrals in fluorinated butenes result in complex torsion profiles. This requires a detailed analysis on possible functional forms to reproduce the torsion profiles, and its influence on simulation studies on liquid viscosities. This analysis has also to be performed with regard to the transferability of the torsion parameters.The studies will be carried out on the basis of different HCFO compounds and fluorinated butenes that are currently proposed as new working fluids for various applications. The extended force field will then be employed for molecular simulation studies on the vapor-liquid phase equilibria and liquid phase densities and viscosities of the pure compounds and different binary mixtures. The molecular simulation results will be used by cooperation partner to develop equation of state (EOS) models for these systems. The EOS models will then be employed in system simulation studies on thermal systems for selected binary mixtures to illustrate the use of information from molecular simulations to evaluate new working fluids.

• DFG Programme: Research Grants