Asymptotic structure of planar nonadiabatic reverse combustion fronts in porous media

Journal Article · Fri Aug 01 04:00:00 EDT 1986 · Combust. Flame; (United States)

DOI:https://doi.org/10.1016/0010-2180(86)90016-7· OSTI ID:5329927

Britten, J A; Krantz, W B

A leading-order analytic analysis of the structure of a planar nonadiabatic reverse combustion (RC) front in a combustible porous medium has been performed by use of matched asymptotic expansions in the activation energy of the combustion reaction. The model considers the irreversible reaction of oxygen in a feed gas flow with an excess of a single-component gaseous fuel devolatilized from the medium, according to one-step, first-order kinetics characterized by a large activation energy. A heat loss term linear in the local temperature difference and an infinite effective Lewis number are assumed for this two-phase combustion process. The analysis determines conditions for the extinction of the steady RC front in terms of the heat loss strength and oxidant flux, and shows the existence of two solutions for heat losses below the extinction value. The predicted dependence of the steady front velocity and temperature on the heat loss intensity agree qualitatively with experimental observations.

• Research Organization: Lawrence Livermore National Lab., Livermore, CA 94550
• OSTI ID: 5329927
• Journal Information: Combust. Flame; (United States), Journal Name: Combust. Flame; (United States) Vol. 65:2; ISSN CBFMA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
ACTIVATION ENERGY
ASYMPTOTIC SOLUTIONS
CHEMICAL REACTION KINETICS
COMBUSTION KINETICS
DEVOLATILIZATION
ELEMENTS
ENERGY
ENERGY LOSSES
FLUID FLOW
FUELS
GAS FLOW
GAS FUELS
HEAT LOSSES
KINETICS
LOSSES
MATERIALS
NONMETALS
OXIDIZERS
OXYGEN
POROUS MATERIALS
REACTION KINETICS
RESEARCH PROGRAMS
TEMPERATURE DEPENDENCE