Investigation of Extinguishment by Thermal Agents Using Detailed Chemical Kinetic Modeling of Opposed-Flow Diffusion Flames.
Investigation of Extinguishment by Thermal Agents Using
Detailed Chemical Kinetic Modeling of Opposed-Flow
Pitts, W. M.; Blevins, L. G.
Chemical and Physical Processes of Combustion, Fall
Technical Meeting. Proceedings. Combustion
Institute/Eastern States Section. October 10-13, 1999
Raleigh, NC, 184-187 pp, 1999.
Sponsor:Deparment of Defense, Washington, DC
halon alternatives; diffusion flames; extinguishment;
combustion; diluent gases; diluents; fire extinguishing
agents; fire suppression; laminar flames; reaction
kinetics; temperature effects
The manufacture of halons, which are widely used in fire
extinguishing systems, was banned in 1984. The search
for effective alternatives continues with a large effort
known as the Next Generation Fire Suppression Technology
Program (NGP). As part of the NGP, NIST is investigating
whether highly effective thermal agents, which obtain
their effectiveness solely by heat extraction and
dilution, are feasible. The paper by Sheinson et al.
provides a good introduction. Simple heating (i.e.,
heat capacity), phase changes, endothermic molecular
decomposition (which is classified as a physical process
as long as the initial agent and its products do not
participate in the combustion chemistry), and simple
dilution can modify flame temperatures and therefore
contribute to flame extinction This paper summarizes the
results of a detailed chemical kinetic modeling
investigation of laminar opposed-flow methane/air
diffusion flames designed to provide an improved
understanding of the extinguishment of fires by thermal
agents. A particular focus was to test the hypothesis
that the effectiveness of a thermal agent depends on the
location of heat absorption relative to the flame zone.
An internal report has been prepared summarizing the
kinetic modeling and also includes the results of an
extensive data base search of potential thermal agents
and modeling results for the effectiveness of thermal
agents in cooling solid surfaces.