Reduction and applicability of chemical kinetic model for ethylene detonation simulation

The selection of chemical reaction kinetic model is essential in detonation simulation. However, how to obtain an appropriate kinetic mechanism to describe chemical reaction process is still an open question, even for the common ethylene detonation simulation. Since the complete detailed mechanism is extremely time consuming in detonation simulation, single-step or several-step simplified models are widely used, although not capable to realistically reproduce unsteady processes in some detonation studies, especially for detonation initiation and failure. Therefore, a series of studies on the reduction, validation and applicability of chemical reaction kinetic model for ethylene detonation are carried out. First, a reduced kinetic model with 55 reactions and 26 species is proposed for ethylene, based on the detailed kinetic model of USC 2.0. A combination method of path flux analysis and sensitivity analysis is used to initially develop a skeleton model, which is employed to acquire a reduced kinetic model by the sensitivity analysis method. Then, predictive performance of the proposed reduced kinetic model is extensively investigated for one-dimensional steady detonation, one-dimensional and two-dimensional unsteady detonation, as well as zero-dimensional constant volume explosion. The results show that the present reduced model is well suitable for detonation simulations within a broad range of conditions. Compared with three typical reduced models in the literature, the present model performs much better overall, particularly in unsteady ethylene detonation simulation. This work provides a valuable roadmap and solution for the development and selection of chemical reaction kinetic models in detonation simulation.