Skeletal mechanism development for a 3-component jet fuel surrogate using semi-global sub-mechanism construction and mechanism reduction

A skeletal mechanism with 110 species and 352 reactions is developed from a detailed mechanism that includes 369 species and 2691 reactions for a 3-component jet fuel surrogate which is composed of methylcyclohexane (MCH), n-dodecane and m-xylene. Firstly, the semi-global sub-mechanisms of MCH and n-dodecane are constructed to substitute the corresponding portions in detailed mechanism, the construction is guided by main reaction pathways and involves isomer lumping, parallel reaction lumping and reaction product substituting, the rate parameters of key reactions are tuned via genetic algorithm (GA) to fit ignition delays. Secondly, the aromatics and base sub-mechanisms are reduced by DRGEP and iterative sensitivity analysis (ISA). ISA calculates the sensitivity parameter for every objective and only removes the one with the lowest value in every iteration. This approach could remove redundant species and reactions effectively. The skeletal mechanism is validated against ignition delays in shock tube, laminar flame speeds and species concentration profiles in shock tube and plug flow reactor over a wide range of conditions. Furthermore, the skeletal mechanism is employed to simulate 3D jet fuel spray combustion and ignition delay times are validated against experimental data.