Development of Physical-Chemical Surrogate Models and Skeletal Mechanisms for the Combustion Simulation of Several Jet Fuels

The physical–chemical surrogate models for S-8, Jet-A, and RP-3 fuels to capture their physical and kinetics properties have been developed in this study. n-dodecane (nC₁₂H₂₆), 2,5-dimethylhexane (C₈H₁₈-25), and toluene (C₆H₅CH₃) were chosen as candidate surrogate components and formulated by the function group based surrogate fuel methodology. Some important physical properties and spray characteristics for S-8, Jet-A, and RP-3 surrogate models were validated. The results indicate that present surrogate models can well emulate various physical properties to accurately reproduce the spray characteristics. Then, a minimal and high-precision surrogate skeletal mechanism that can be suitable for computational fluid dynamics (CFD) simulations was developed and validated against some fundamental combustion experiments for each surrogate component. Furthermore, the performances of surrogate models that contain the surrogate formulation and associated skeletal mechanisms were validated against the experimental data on ignition delay times (IDTs), species concentration profiles, and laminar flame speeds (⁠$Su0$⁠) in a wide range of conditions. Finally, the surrogate fuels were used to combustion CFD simulations to model the spray combustion process in a constant volume combustion chamber. It can be seen that the agreements between the simulation and experiment in fundamental and spray combustion characteristics are reasonably good, which proves that present surrogate models are accurate and robust to be applied in CFD simulations.