Optimization study of spray detonation initiation by electric discharges

Detonation initiation techniques for pulse detonation propulsion

“…The spiral was mounted 70 mm downstream from the prevaporizer nozzle. In the experiments with both tubes, the prevaporizer wall temperature was 190 ± 10 • C. • C. The (continuously) moving fuel air mixture was ignited in the prevaporizer either by a standard spark plug or by the threeelectrode discharge [11]. The results of experiments were well reproducible once the ignition was triggered after the tube was purged by the reactive mixture in the amount of 3 4 tube volumes.…”

“…Mixing of fuel and air starts in the air-assist atomizer and terminates in the detonation tube of internal diameter 51 mm and 3 m long. The air-assist atomizer provides very ¦ne kerosene drops mainly 5 to 10 µm in diameter (measured by the phase Doppler particle analyzer (PDPA) and soot- sampling method [10,11]). The two-phase fuel air mixture of equivalence ratio 1.2 ± 0.1 is continuously injected to the prevaporizer section 15 of the detonation tube with the total mass §ow rate at the level of 80 g/s.…”

“…To avoid poorly reproducible initial DDT stages (i) to (iii), the primary shock wave was generated either by an electric discharge [7 10] or by an additional tube section with Shchelkin spiral [10,11].…”

Initiation of heterogeneous detonation in tubes with coils and Shchelkin spiral

“…The pulse duration was 1 s, and the initial temperature of air and fuel was 293±4 K. An electric discharger D was located at a distance of 60 mm from the burner nozzle. A detailed description of the characteristics of the burner and discharger is given in [9,12].…”

“…In experimental studies [5,7,8], the heterogeneous ("dropping") detonation is initiated by strong sources such as shock wave (SW) [5], gas detonation [7], or explosive charge [8]. In [9][10][11][12][13], the detonation of liquid fuel sprays in air was initiated by one or two electric discharges. In dropping mixtures of liquid fuel with oxygen gas, the CDT was observed in [14], where the length of the pre-detonation section was varied from 20 to 100 tube diameters.…”