Trace-analysis of a combustion wave thermal instability using high-speed video images: experiment and simulation modeling

Abstract

The paper presents a method for identifying the thermal instability mode of a combustion wave during self-propagating high-temperature synthesis (SHS) of materials during high-speed television recording. Compressing video data using the differential chronoscopy method (DCS) reduces the data size by more than 1000 times without losing information about the motion of the combustion wave of the SHS, and the result is obtained as a two-dimensional chronogram, the mathematical model of which is presented for the Ni-Al system with an admixture of inert powder impurities from 1 to 15 % Statistical characteristics based on the analysis of traced images of DCS maps are suggested for recognizing the critical mode of the SHS combustion. The sensitivity of recognition of changes in the discrete thermal structure of SHS wave is estimated using the proposed statistical characteristics of the trace transformation images of the DCS maps. In addition, using the various functional "cores" of the Trace transformation, the highest value of this sensitivity was determined. As a result of this comparison, the most effective of the considered functional “cores” of the Trace transformation was determined, which allows defining unstable combustion modes in SHS technology. Comparison of the histograms of the distribution of Trace-matrices for the experiment and simulation showed good agreement.