Continuous detonation of the liquid kerosene–air mixture with addition of hydrogen or syngas

Regimes of continuous detonation of heterogeneous mixtures of aviation kerosene and air with addition of hydrogen or syngas are studied in a flow-type annular cylindrical combustor $503$ mm in diameter. With variations of the flow rates of air, liquid kerosene, hydrogen, and their relationships, regimes of continuous spin detonation are obtained in the following ranges: number of detonation waves $1$–$5$, detonation wave velocity $1.15$–$1.67$ km/s, and wave rotation frequency $0.73$–$4.86$ kHz. In the case with addition of syngas with the composition $\mathrm{CO}+3\mathrm{H}_2$, regimes with two opposing transverse waves are obtained; the mean velocity of wave rotation is $0.66$–$1.47$ km/s, and the frequency is $0.85$–$1.87$ kHz. Bubbling of the gaseous fuel (hydrogen or syngas) through liquid kerosene in the fuel injection system makes it possible to reduce the mass fraction of the gas in the two-phase fuel down to $8.4\%$ for hydrogen and $47\%$ for syngas with the composition $\mathrm{CO}+3\mathrm{H}_2$. It is demonstrated that the minimum fraction of syngas in kerosene that still ensures the detonation regime is determined by the amount of hydrogen. Based on the stagnation pressure measured at the combustor exit, the specific impulse in the case of continuous detonation is determined as a function of the two-phase fuel composition. The maximum value of the specific impulse (about $4000$ s) is obtained for the mass fraction of hydrogen in the two-phase fuel equal to $42\%$. The minimum diameter of the annular detonation combustor is estimated as a function of the specific flow rate of the heterogeneous mixture.