Quantitative effect of Ar dilution on the dynamic detonation parameters in acetylene–oxygen mixtures

Abstract

In order to clarify the effect of Ar dilution on the dynamic parameters of detonation quantitative, smoked foil records of C 2 H 2 –O 2 with different Ar dilutions are investigated. With the Ar concentration increasing, the instability will decrease and detonation can fail more easily. Histograms, variance measurements, and studies of the autocorrelation function are systematically considered to quantitative define the irregularity parameters. The other kinetics characteristics, such as detonation limits, velocity, and cell size, are also analyzed to illustrate the dilution effects via the smoke foils from different Ar dilution. It was found that the results from histograms, variance studies, and the autocorrelation function consistently show the tendency that mixtures with different Ar dilutions exhibited different degrees of irregularity. Quantitative irregularity can be examined by the values of the ratio Max discrepancy/Relevant mean cell size of C 2 H 2 + 2.5O 2 . For the mixtures with higher Ar concentration, the main cell size shown by the peak in the histogram and the first peak of the autocorrelation function were much closer to the cell size measured visually because of the stronger dominant mode and more regular trajectory of triple-point patterns. Predictions of the cell size considering the participation of Ar in the mixtures were also given.