Analysis of combustion characteristics in a reverse-flow pulse detonation combustor

The reverse-flow pulse detonation combustor (PDC) effectively overcomes the excessive length issue of straight-tube detonation combustors, which restricts their engineering application. To investigate the combustion characteristics of the reverse-flow PDC, a combined approach of numerical simulation and experimental testing was employed to study the cold flow field, fuel spray field, detonation characteristics, pressure gain characteristics, and stable working characteristics under various engine inflow conditions. The results show that the detonation bend section accelerates the deflagration to detonation transition (DDT) and suppresses backpressure propagation. The DDT distance decreases with higher inflow conditions, reaching its shortest value of 556.5 mm at 30 Hz. The combustor pressure gain ratio first rises then falls, while the detonation section's pressure gain ratio keeps increasing. The maximum combustor pressure gain ratio is 2.31. The lean flameout limit generally drops with higher frequencies, the rich flameout limit decreases then increases. The stable working oil-gas ratio range increases with the operating frequency, reaching a maximum of 0.015.