Numerical Studies of Multi-cycle Acetylene-air Detonation Induced by Shock Focusing

Shock focusing techniques can avoid deflagration-to-detonation transition (DDT), which make PDE more efficiency. Numerical simulations of an idealized pulse detonation engine consisting of axial inlet and circumferential inlet are presented in this paper. Using detailed acetylene-air chemical kinetic model, investigation on detonation direct initiation by shock focusing is done. Studies indicate that in static flow field, the regions of high temperature and pressure created by shock focusing can produce detonation at the condition of circumferential inlet Mach 2.4. But in dynamic flow field, Mach number should increase to 3.5 to achieve detonation.