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.

Keywords:

• Aircraft safety
• Hydrocarbon ignition
• Moving hot surface

Acknowledgments

Urszula Niedzielska is grateful to Polish–U.S. Fulbright Commission for sponsoring her stay at Caltech as a Visiting Special Student. Josué Melguizo-Gavilanes is grateful to the Natural Sciences and Engineering Research Council of Canada (NSERC) for providing a Postdoctoral Fellowship.

Funding

The present work was performed at the Explosion Dynamics Laboratory of the California Institute of Technology and was partly supported by the Boeing Company through a Strategic Research and Development Relationship Agreement CT-BA-GTA-1 with Arthur Day as a technical monitor.

Additional information

Funding

The present work was performed at the Explosion Dynamics Laboratory of the California Institute of Technology and was partly supported by the Boeing Company through a Strategic Research and Development Relationship Agreement CT-BA-GTA-1 with Arthur Day as a technical monitor.