High-speed chemiluminescence imaging was performed in three horseshoe-shaped detonation channels in order to study the stability the stability of detonation waves as they propagate along a bend. The dimensions of the three channels were designed to promote two-dimensional detonations by limiting the depth dimension below the expected cell size. The three channels have widths ranging from 1.5 -2.4 inches, but share a common ratio of inner-to-outer radius of 4/5. Ethylene-air mixtures of equivalence ratio ranging from 0.7 - 1.8 were used for the reactants. Analysis of the high-speed imagery showed that the detonations became unstable when traveling around the 'U' portion of the horseshoe for all cases, but failed for both lean and overly rich mixtures. Detonation failure was marked by dissolution of the wave front, and wavefront re-initiation occurred most often along the outer radius. Backward-propagating detonation waves were observed intermittently during re-initiation events. Trends observed in this study agree approximately with previous studies of hydrogen-air mixtures.
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