(395d) Modeling of Nitrogen + Fuel Phase Behavior Using the Helmholtz-Energy-Explicit Equation of State

The commercial jet fuel market is expected to grow from 106 billion gallons to 230 billion gallons by 2050 globally. Unlike for light-duty vehicles, electrification of the aviation industry is not expected to happen in the near future. Thus, sustainable aviation fuel (SAF) remains a promising, renewable, alternative to petroleum derived fuel. SAF can be produced biowaste and is made up of chemical species mirroring those found in petroleum derived fuels including n-paraffins, iso-paraffins, and naphthenes (ring/cyclic compounds). The extreme conditions the fuel is exposed to throughout the injection and combustion process are pressures up to 100 MPa and temperatures exceeding 700 K. High fidelity equations of state (EoS) that apply to SAF to enhance the design of jet engines using computational fluid dynamics are needed. Currently, REFPROP (version 10.0) includes multiparameter pure fluid EoS for several compounds included in SAF. However, the appropriate algorithms and mixture models needed to study mixtures of fuel-nitrogen (as a surrogate for air) are not currently available in REFPROP. In this study we employ the Templated EQuation of state Package (teqp) to model fuel-nitrogen mixtures using the Helmholtz-energy explicit EoS. The performance of the Helmoholtz-energy-explicit EoS is compared to existing models previously used to model fuel-nitrogen mixtures such as the PC-SAFT EoS. The overarching goal of this project is to assess the performance of the Helmholtz-energy-explicit model for its eventual incorporation into future versions of REFPROP.