The correlation of the DDT run-up distance to the amplification factor in propane-oxygen mixtures

An experimental study was conducted to investigate the effect of propane-oxygen mixtures composition on the DDT run-up distance in a smooth tube. Two typical deflagration-to-detonation transition processes were shown, which were induced by a localized explosion originating near the turbulent flame or by the precursor shock wave. The DDT run-up distance based on the trajectory intersection method was approximately equal to 0.5 times the amplification factor. The amplification factor only depended on the specified initial conditions of reactant mixtures, which means that this correlation can predict the minimum necessary distance for DDT to occur when the initial conditions of the reactant mixtures are known, which can be applied in the design of predetonator in pulse detonation engine. The amplification factor was associated with the comprehensive form of gas dynamic and the turbulence feedback mechanism. The composition of the mixtures was only related to the gas dynamic feedback mechanism, and affected the DDT run-up distance. This is an abstract of a paper presented at the 30th International Symposium on combustion (Chicago, IL 7/25-30/2004).