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Selection of a CF3Br Simulant for Use in Engine Nacelle Certification Tests.


pdf icon Selection of a CF3Br Simulant for Use in Engine Nacelle Certification Tests. (2238 K)
Womeldorf, C. A.; Grosshandler, W. L.

NIST SP 890; Volume 2; Section 12; November 1995.

Fire Suppression System Performance of Alternative Agents in Aircraft Engine and Dry Bay Laboratory Simulations. Volume 2, Gann, R. G., Editor(s), 591-621 pp, 1995.

Available from:

National Technical Information Service
Order number: PB96-117783

Keywords:

fire suppression; aircraft engines; nacelle fires; simulation; halon 1301; halon alternatives; aircraft certification; pentafluoroethane; sulfur hexafluoride; boiling point; halon simulants; critical temperature

Abstract:

This section describes the requirements and selection of a simulant of CF3Br for the purpose of certification testing engine nacelle fire suppression systems. To illustrate the storage, delivery, and distribution requirements of CF3Br, relevant characteristics of engine nacelle fire suppression systems and certification tests are briefly summarized. An initial screening of over 1300 chemicals based on the boiling point, critical temperature, and molecular weight of CF3Br is described, and the nine potential candidate simulants that were found are listed. Three final candidates (SF6, C2HF5, and CHC1F2) were selected for experimental testing based upon their saturated vapor pressures, Jakob numbers, and the requirements of this application: ozone depletion potential, flammability, corrosiveness, toxicity, stability and atmospheric lifetime. To evaluate the hydraulic properties of the simulants, as compared to CF3Br, pressure traces of discharges through a piping system into cooled recovery bottles and to atmosphere are compared with like tests of CF3Br. To compare the discharge spray distribution of the simulants with CF3Br, high speed movies of the plumes at the end of the piping system were taken and are described. Results and conclusions from comparisons of the three candidate simulants with CF3Br are presented and discussed.