Effect of Detonation Instability and Initial Pressure on Track Angle of Spinning Detonation

Experiments were conducted in the detonation tube with an inner diameter of 63. 5 mm to study the effect of initial pressure and detonation instability on track angle. In the detonation experiments, four typical premixed mixtures (which could be divided into stable mixtures such as I:2H2 + O2 + 50% Ar, II:C2 H2 + 2.5O2 + 85% Ar and III:C2 H2 + 5N2 O, and unstable mixtures such as IV:CH4 + 2O2 ) were used. During the experiments, the cellular structure of the spinning detonation wave was recorded on the smoked foils. And then, the track angles α + / α - between the right-handed / left-handed transverse waves and the tube axis were measured under different pressures. At the meantime, the variation of track angle and the influence of initial pressure and gas instability on track angle were analyzed. The results were obtained as follows. The track angles of the four premixed mixtures were in the range of 30̊ ~ 50̊. For the gases (I, II, III) with relatively weak detonation instability, the measured values of track angle were in good agreement with theoretical values. However, for the gas with high instability (IV), the agreement was poor. The magnitude and variation trend of the dispersion of track angle was consistent with those of the cellular structure dispersion. In addition, the higher the initial pressure, the smaller the track angle. As the initial pressure increases, the track angles of the four premixed gases were all significantly decreased, and the decrease was basically consistent. Finally, in the high-frequency spinning phase, the effect of initial pressure on track angle was stronger than that of detonation instability. © 2023 China Ordnance Society. All rights reserved.