A study on the extinction of a stretched cylindrical premixed flame.

Abstract

For the basic investigation of a premixed flame subjected to the effects of both flame stretch and flame curvature, we took up the stretched cylindrical flame formed inside the porous cylinder when the mixture was ejected uniformly from the inner wall surface of it. With methane/air and propane/air mixtures, flame behavior observations and measurements of extinction limit and flame diameter were made for these flames, and the effects of flame stretch and flame curvature were discussed, including those of heat loss to the burner wall, buoyancy, and Lewis numbers of reactants. Theoretical analysis was also made and extinction limits of the cylindrical flame and counter-flow twin flames, which have no flame curvature effects, were calculated and compared. The results showed that the curvature of the cylindrical flame propagating outward weakness resistibility to the flame extinction due to stretch.