Thermodynamic modeling of trans/supercritical fuel sprays in internal combustion engines based on a generalized cubic equation of state

Redlich-Kwong-Peng-Robinson (RK-PR) was developed in recent years as a promising generalized cubic equation of state (EoS) to allow for a good representation of fluids with different critical compressibility factors (Zc), but it cannot be mathematically applied to high Zc fluid such as H2 and CO, thus limiting its application on engine problems. In this work, the Zc ratio was modeled as a function of Zc to extend the calculable range of RK-PR and to achieve higher accuracy for various n-alkanes, liquid oxygen and nitrogen. The thermodynamic and transport properties framework based on RK-PR show superiority over those of SRK and PR for typical IC engine fuels and spray mixtures. In addition, the high-fidelity simulations of n-dodecane spray were performed to investigate qualitatively and quantitatively the effects of EoS and thermodynamic conditions on trans/supercritical spray behavior and characteristics, emphasizing the necessity of applying an accurate EoS for high fidelity spray simulations.