The flame structure temperature and extinction limits of confined diffusion flames were investigated using an asymptotic model that considers the excess/deficient enthalpy at the reaction region. The effects of the heat exchange between gas and solid phases on the flame structuren was examined. When the heat removed from the flame by the solid matrix was large the flame could be extinguished since the lowering in the flame temperature led to increasingly large leakage of reactants through the flame sheet. This occurred when the porosity or the mass injection rate was small enough. The extinction limit linked with a small value of the mass injection rate adds to the kinetic extinction limit which is linked with a large value of the mass injection rate to characterize a dual-extinction-point behavior for the case considered. When the porosity of the medium reached a minimum critical value these two distinct extinction points collapsed. Consequently it is possible to construct a flammability map for the confined diffusion flame where the critical porosity defines an absolute flammability limit.
- Asymptotic analysis
- Diffusion flame
- Porous medium
ASJC Scopus subject areas
- Chemical Engineering(all)
- Mechanical Engineering
- Physical and Theoretical Chemistry
Stabilization and extinction of diffusion flames in an inert porous medium. / Endo Kokubun, M. A.; Fachini, F. F.; Matalon, M.In: Proceedings of the Combustion Institute, Vol. 36, No. 1, 01.01.2017, p. 1485-1493.
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