Comparing Chemical Reaction Mechanisms for Jet Fuel in Turbulent Premixed Combustion Simulations

The compositions of alternative jet fuels can vary radically, and the consequences of these differences are a subject of ongoing investigation. Numerical combustion simulations are vital to this research and require chemical reaction mechanisms that efficiently and accurately capture the chemical pathways of combustion. Here, we present the recently developed Z79 collection of small pathway-centric reaction mechanisms for n-heptane, Jet A JP-5, and the two alternative jet fuels, C1 and C5. A novel ethanol mechanism, Z74 Ethanol, is also presented. All mechanisms are validated for laminar burning velocities and ignition delay times, capturing these key parameters for a range of initial gas temperatures and equivalence ratios. The mechanisms are also validated in large-eddy simulations (LESs) of a turbulent premixed bluff-body flame. In the LES, the new mechanisms for ethanol, n-heptane, and Jet A match available experimental data well, whereas the C1 mechanism slightly underpredicts the flame size. The flame size is correlated with the temperature ratio between reactants and products, and the temperature ratio trend in the LES is the same as in laminar flame simulations.