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Analysis of the Wright Patterson Full-Scale Engine Nacelle Fire Suppression Experiments.

pdf icon Analysis of the Wright Patterson Full-Scale Engine Nacelle Fire Suppression Experiments. (7985 K)
Hamins, A.; Cleary, T. G.; Yang, J. C.

NISTIR 6193; 121 p. November 1997.

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aircraft safety; nacelle fires; blowout velocity; flame extinguishment; flammability limits; halogenated compounds; ignition; sprays; fire suppression


An analysis is presented on the full-scale suppression experiments conducted during 1996 and 1997 in the F-22 engine nacelle fire simulator at Wright Patterson Air Force Base. Experiments investigated the relative effectiveness of halogenated agents and solid propellant gas generators (SPGG) in suppressing a series of spray fires with and without a fuel re-ignition source. Several agents were tested including halon 1301, HFC-125, and two basic types of SPGG which included those that produced inert gases in conjunction with a fine solid particulate (some which contained K2CO3), and those that produced inert gases only. The SPGG devices were more or less effective depending on the agent composition and the agent delivery rate. The SPGG effluent which contained a significant percentage of K2CO3 particulate was particularly effective for re-ignition protection, a scenario which dominates agent mass requirements for the compressed halogenated liquids. A number of measurements were made during the suppression tests. Measurements included gas temperatures, the re-ignition source temperature, the cold-flow agent concentrations (no fuel spray or fire present), and velocity measurements. This information was with the different suppressant types. A simple model for SPGG delivery was developed. Assuming plug type flow, the transient average agent concentrations were calculated in the nacelle and compared to measurements. The results give reasonable agreement.