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Effects of Fire Suppressants on Ignition Characteristics of Propane-Air Mixtures



Gregory T. Linteris, Viswanath R. Katta, Fumiaki Takahashi, Harsha K. Chelliah, Oliver Meier


A numerical investigation is performed for understanding the ignition behaviors of CF3Br and R- 125 fire-suppressing agents in propane-air-agent mixtures. Two types of simulations are considered in an attempt to provide insight into the FAA’s Aerosol Can Explosion tests. The premixed case (fuel, air and agent perfectly mixed prior to ignition) is treated in the homogeneousignition model. The diffusion-limited case (incomplete mixing of fuel, air and agent prior to ignition), which simulates the injection of fuel into the partially heated mixture of air and agent in the FAA tests, is considered in the opposing-fuel-heated-air-jet model. A time dependent, finiterate chemistry, two-dimensional code (UNICORN) is used for the simulation of ignition process in these two mixing models. A 177-species, 2986-reactions detailed chemical kinetics model is incorporated in UNICORN code. Homogeneous-ignition calculations suggest that ignition delay times in the fuel-lean, stoichiometric, and fuel-rich mixtures increases with the addition of either CF3Br or R-125. On the other hand, ignition is retarded in the mixing layers of the opposing jets of propane and heated-air-agent mixtures when CF3Br is used, while ignition is accelerated with R- 125. It is found that R-125 decomposes more than CF3Br in heated air, which leads to greater production of H, O, and OH radicals and acceleration of ignition process.
Proceedings Title
7th US National Combustion Meeting
Conference Dates
March 21-23, 2011
Conference Location
Atlanta, GA


Halon replacements, cargo-bay fires, fire suppression, CF3Br, HFC-125, ignition, aerosol can test


Linteris, G. , Katta, V. , Takahashi, F. , Chelliah, H. and Meier, O. (2011), Effects of Fire Suppressants on Ignition Characteristics of Propane-Air Mixtures, 7th US National Combustion Meeting, Atlanta, GA (Accessed June 16, 2024)


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Created December 6, 2011, Updated February 19, 2017