Flame behaviors and explosion characteristics of two-phase propylene oxide/air mixture under different ambient pressures

Propylene oxide (PO) is widely used in fuel-air explosives and pulse detonation engines. Based on computational fluid dynamics, the effects of ignition position, initial pressure, and mass concentration on the explosion characteristics of the PO/air mixture were studied by using a 20 L spherical container. The results showed that the ignition position had a significant effect on the flame structure. When the fuel cloud was ignited at the center, the flame structure experienced spherical, elliptical, and tulip shapes. The explosion time first decreased and then increased with the increase of ignition position, while the maximum explosion pressure decreased correspondingly. The maximum explosion pressure and the temperature had an inverted “U” correlation with concentration at normal pressure. However, the overpressure was insensitive to concentration in the negative pressure condition. The maximum flame temperature showed different flame behaviors under different initial negative pressures and cloud concentrations. This study provides a theoretical basis for understanding the explosion behaviors of PO/air mixture with different ignition positions and initial vacuum pressures, which is of great significance in preventing explosion accidents.