Chemical Kinetics of n-Hexane-Air Atmospheres in the Boundary Layer of a Moving Hot Sphere

Abstract

The present article focuses on the chemical kinetics of the ignition of premixed n-hexane-air atmospheres by a moving hot sphere with emphasis on the role of low-temperature chemistry (T < 1000 K). Experiments were performed to measure the minimum surface temperature for ignition of a propagating flame and nonreactive two-dimensional simulations were performed to estimate the temperature a parcel of fluid experiences as it travels within the thermal boundary layer near the surface of the sphere. Reactive simulations using detailed reaction models and a one-step model were used to investigate the chemical reaction dynamics in a constant pressure reactor with a variable heat transfer coefficient, which reproduces the temperature history. It was found that, under the specific conditions studied, the chemistry is activated at T > 1000 K with no noticeable impact of the low-temperature chemical pathways.