REDUCTION OF LARGE DETAILED KINETIC MECHANISMS: APPLICATION TO KEROSENE/AIR COMBUSTION

Reduction of a large detailed mechanism for kerosene, including 225 species and 3493 irreversible reactions, was executed over a wide range of parametric conditions. Numerical simulations were tested for a perfectly stirred reactor with four pressures (0.5, 1.0, 3.0, and 10.0 bar), six equivalence ratios (0.5–2.0), and six inlet temperatures (from 300 to 1800 K). The reduction process was carried out with an improved and adapted method including three different stages. First, atomic flux analysis eliminates 91 useless species and their 1361 corresponding reactions. This skeletal mechanism is squeezed again by removing the remaining redundant reactions with the principal component analysis method. A new skeletal mechanism including 134 species and 1220 reactions is obtained. The ultimate step of the reduction process consists of decreasing computational time by using the quasi-steady-state approximation for species with a short lifetime. A convergence accelerator reduces the number of iterations necessary to solve the algebraic system. Two reduced schemes including 33 and 40 differential species were achieved: they present a good compromise between predictive qualities (from 68 to 75% of species are reproduced with an error level lower than 10%) and calculation speedup (average computational time savings of a factor of 5.3 to 4.8 are obtained between reduced and initial detailed mechanisms).