Development of a Gasoline and Jet Fuel Blend Kinetic Mechanism using Hybrid Response Surface Networks

Understanding sustainable aviation fuels is becoming increasingly important as there is a significant push to introduce them into the current fuel infrastructure. This study presents a method to develop a blended mechanism between two fuels, gasoline and F-24, with dramatically different ignition characteristics as would be found in many blends of a SAF with a conventional jet fuel. In previous works, mechanisms have been developed through a data-driven optimization process that allows for the fitting of reaction rates coefficients to experimental ignition delay data. This approach creates mechanisms with accurate predictions of ignition delay at the target conditions but introduces unknown levels of uncertainty in the species histories, and the model predictions at conditions not specified in the experimental data. To further understand this uncertainty, a hybrid response surface technique was created that can rapidly optimize the mechanisms towards the experimental data many times to create a distribution of solutions. Ignition delays were measured for gasoline, F-24, and 25/75, 50/50, and 75/25 volumetric blends of the two fuels at temperatures ranging from 650 to 1300 K, pressures of 20 and 30 bar, and equivalence ratios of 0.5, 1.0, and 1.3. A mechanism for the gasoline and F-24 blends was developed using a data-driven optimization method. Using the hybrid response surface method, a distribution of solutions to the data-driven optimization problem was found for the blend mechanism. The distribution of solutions showed the variability in solutions by examining the results of simulations not specified in the target experimental data. The variability in the results showed decreased uncertainty as the blend ratio of gasoline decreased. Two experimental pressure conditions provided an improved constraint on the pressure dependence and therefore the applicable range of the final mechanisms. From these results, a blend mechanism of F-24 and gasoline was suggested.