Suppression of a Non-Premixed Flame Behind a Step

Published

January 1, 2000

Author(s)

William L. Grosshandler, R Charagundla, Anthony P. Hamins, Kevin B. McGrattan, Cary Presser

Abstract

Because of its many positive attributes, halon 1301 or trifluorobromomethane (CF₃Br), has been used as a fire extinguishing agent in many applications, including aircraft, ships, and specialized structures. Due to its high ozone depletion potential, however, world-wide production was halted in 1994. In the search for a long-range replacement, novel types of extinguishing agents and delivery mechanisms are under development. To gauge the suitability of a replacement agent, methods are needed to evaluate the material's suppression effectiveness under conditions that relate to field applications. In this study, a laboratory-scale facility has been developed to screen the suppression effectiveness of agents that are delivered in a transient fashion, such as solid propellant gas generators. The facility features a pool fire stabilized behind an obstruction, which is known to be a challenging suppressionconfiguration. The character of the flame and the impact of the air flow, propane flow, obstruction geometry, and rate of agent addition on the amount of material needed for suppression are examined for N₂ and CF₃Br. The impact of the injection process on the flowfield and the transport of the agent downstream are examined. A simple mixing model is useful to explain the observed trend of decreasing suppressant mass fraction with increasing injection duration, even for agents as different as CF₃Br and N₂. Direct numberical simulation of the suppression event is shown to successfully predict the puantity and rate of N₂ required to extinguish the flame based upon a published global reaction rate for premixed propane/air flame propagation.

Citation

Symposium-A Quarterly Journal in Modern Literatures

Volume

28

Pub Type

Journals

Download Paper

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Keywords

baffle stabilized flames, direct numerical simulation, fire suppression, Halon 1301

Citation

Grosshandler, W. , Charagundla, R. , Hamins, A. , McGrattan, K. and Presser, C. (2000), Suppression of a Non-Premixed Flame Behind a Step, Symposium-A Quarterly Journal in Modern Literatures, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=860026 (Accessed April 18, 2024)