Kinetic Modelling of Hydro-Processed Renewable Jet Fuel Combustion in a Constant Volume Combustion Chamber

Sustainable aviation fuel (SAF) is anticipated to play a crucial role in achieving the ‘Fly Net Zero’ target. Hydro-processed renewable jet (HRJ) is a certified SAF that can be blended with conventional jet fuel as a drop-in replacement. This study focuses on developing a reduced kinetic model for the combustion of HRJ fuel in a constant volume combustion chamber (CVCC) using CHEMKIN-PRO. The simulations are performed using the zero-dimensional (0-D) closed homogeneous batch reactor (CHBR) model. The objective is to formulate a surrogate model with simplified chemistry suitable for CVCC applications. The detailed kinetic mechanism employed in this study comprises 307 species which has been extensively validated against experimental data. Various strategies for kinetic reduction are explored using the Reaction Workbench in CHEMKIN-PRO to formulate a 3-component fuel surrogate, and the resulting simplified kinetic chemistries are compared. Ultimately, a reduced HRJ fuel surrogate model consisting of 111 species and 823 reactions is developed, demonstrating an $8.7 \%$ deviation in ignition time compared to the detailed counterpart. It is found that the ignition delay decreases with increasing initial temperature and pressure. However, equivalence ratios of 0.8, 1.0, and 1.2 show no significant differences in ignition time within the studied range. Apart from these, the reduced kinetic model is able to reproduce the mole fraction profiles of the key reactant and intermediate species when compared to the detailed model.