Prediction of thermochemical and transport properties of hydrocarbon aviation fuel in supercritical state with thermal decomposition

Abstract

A program was developed to predict the physical properties of hydrocarbon aviation fuel that flows in regenerative cooling channels used for scramjet vehicles. The developed program considers the thermal decomposition in the supercritical region. In particular, JP-10 was selected as the representative fuel, and its physical properties were predicted for the fuel flow rate condition of the scram mode. Thermal properties were predicted using the Redlich–Kwong and Peng–Robinson equations of state, and the Maxwell equation. Additionally, a new formula was proposed by reflecting the singularity of Redlich–Kwong and Peng–Robinson equation of state. This approach has not been considered previously. Transport properties were predicted using Brulé–Starling and Chung models. The final physical properties considering thermal decomposition were calculated by applying the conventional mixture rule and the Chung mixture rule. For the thermal decomposition model, the proportional production–distribution (PPD) model reflecting thermal decomposition up to the primary reaction zone and the differential global reaction (DGR) model reflecting thermal decomposition up to the secondary reaction zone were applied based on the experimental data. Regarding the components generated during thermal decomposition and their properties, the calculation results were validated with the experimental data for the range in which experimental results exist. Moreover, they were verified against National Institute of Standards and Technology (NIST) Reference Fluid Thermodynamic and Transport Properties (REFPROP) data for the regions of other ranges. When the DGR model was applied, the physical properties were investigated according to the pressure and fuel conversion rates. The developed program is expected to effectively predict the physical properties of hydrocarbon fuels, for which experimental data exist for the thermal decomposition model.