High-temperature oxidation kinetics of iso-octane/n-butanol blends-air mixture

- A chemical kinetic model of n-butanol/iso-octane blends (BI) was established.
- Model BI was validated against laminar flame speeds, ignition and JSR data.
- Detailed reaction pathway analysis of n-butanol/iso-octane blends were conducted.
- Key species and reactions for acceleration of laminar flame speed were analyzed.

A chemical kinetic mechanism of n-butanol/iso-octane blends (Model BI) was established on the basis of a n-butanol reaction submechanism and part of a high-temperature oxidation mechanism of iso-octane. Model BI was validated against laminar flame speeds, ignition delay times and JSR data, and proved to be applicable and reliable. It also found that the laminar flame speed of blends increased linearly and monotonically with the increasing ratio of n-butanol. Then detailed kinetic pathway analysis of n-butanol/iso-octane blends were performed based on Model BI to find out the reason for the accelerating effect of added n-butanol. The most influential elementary reactions were determined for the blend, and the laminar flame speed is largely negative related to the concentration of iC4H8, C3H6 and CH3, while C2H4 and C2H3 contribute to the promotion of laminar flame speeds. Flame structures of n-butanol blending with iso-octane were also computed and correspond to the kinetic pathway analysis.