Critical tube diameter for quasi-detonations

The critical tube diameter problem for quasi-detonations is studied via experiments and two-dimensional numerical simulations based on the reactive Euler equations. In experiments, quasi-detonation in stoichiometric acetylene-oxygen mixtures generated rough-walled tubes with three different diameters, where wall roughness introduced by using spiral inserts wire diameters. Photodiodes are placed along rough to record detonation time-of-arrival deduce velocity, a high-speed schlieren system used observe diffraction processes. Near regime of diffraction, emerging from again shown first fail subsequently re-initiate local explosion center spherical deflagration reaction zone. For quasi-detonations, stronger turbulence instabilities produce hot spots, which balances significant velocity deficit as much approximately 15% tube, resulting pressure remaining relative constant. cell sizes directly measured, ratio diameters (dc) these determined (λ) quantify criterion initiation. coil springs, previous dc/λ ≧ 13 re-initiation appears invalid, initiation found 8. Despite enlargement lower propagation quasi-detonation, it hypothesized that increase irregularities or can turn benefit transmission process. These unstable features supported simulations, also showing higher degree irregularities, wider spectrum induction rate, generation shocked pockets.