A new detailed kinetic model for fossil-derived and sustainable aviation fuels – SAF-MechV1.0. Part I: n-alkanes and iso-alkanes

A detailed chemical kinetic model, SAF-MechV1.0, has been developed as the first unified mechanism capable of describing the combustion chemistry of both sustainable aviation fuels (SAFs) from all major production pathways and traditional, fossil-derived jet fuels. As the first of a two-part study, this work focuses on developing C 5 –C 16 n- and iso- alkane chemistries based on unified rate rules and consistent thermochemistry from the latest group additivity values. The n- and iso -alkane chemistries are thoroughly assessed against shock tube, rapid compression machine, jet-stirred reactor, and laminar burning velocity measurements across a wide range of conditions (T = 353–1663 K, p = 0.004–80 atm, and Φ = 0.5–2.0). Predictions accurately reproduce ignition delay times, species concentration, flame velocities, and reactivity trends across both chain-length and extent of chain-branching at diverse temperature, pressure, and fuel loading regimes. Overall, SAF-MechV1.0 (Part I) establishes a chemically consistent and experimentally validated kinetic foundation for n- and isoalkane chemistry, providing the necessary basis for Part 2 that incorporates cycloalkane and aromatic chemistries toward a complete aviation-fuel model. Novelty and significance statement This study presents SAF-MechV1.0, the first comprehensive chemical kinetic model for all major sustainable aviation fuels (SAFs) and fossil-derived jet fuels. As the first of a two-part study, this work introduces several key novelties: (i) SAF-MechV1.0 achieves a vast-ever coverage of n - and iso- alkanes for all major SAFs and fossil-derived jet fuels, encompassing C 5 – C 16 carbon numbers, 12 × n -alkanes, and 20 × iso- alkanes; (ii) the chemistries for these n- and iso- alkanes are developed based on a single, unified rate rule and consistent, latest group values, which is significant as it offers great accessibility for ensuing model improvements whenever necessary; (iii) without prior fine-tuning against any individual alkanes, the single-rate-rule-developed sub-chemistries achieve excellent agreement for all n- and iso- alkanes with a comprehensive validation dataset that covers ignition delay time (IDT), speciation and laminar burning velocity (LBV) measurements over low-to-high temperatures and pressures. This significant advancement highlights the feasibility and advantage of unified rate rules and lays the kinetic foundation for developing SAF-MechV1.0.