Large-scale hydrogen–air continuous detonation combustor

•We conduct experiments in a large-scale continuous-detonation combustor operating on hydrogen–air mixture.•We vary a size of air-inlet slit to observe changes in operation process and propulsion performance.•Widening of slit from 2 to 15 mm leads to decrease in a number of rotating detonation waves and to detonation failure.•Maximum fuel-based specific impulse obtained in experiments is 3000 s.

A large-scale continuous detonation combustor (CDC) has been designed, fabricated and tested to study the effect of different design elements on the operation process and CDC propulsion performance. It has been shown experimentally that widening of the air-inlet slit in the annular combustion chamber from 2 to 15 mm leads to a decrease in the number of detonation waves (DWs) simultaneously circulating in the combustor from four to one and, finally, to transition to the operation mode with intermittent (pulse) longitudinal reaction waves resembling pulse detonations. The number of DWs and the thrust produced by the CDC can be increased by installing a shaped obstacle at the CDC exit nozzle providing the blockage of the combustor cross section. The maximum net thrust produced by the CDC attained 6 kN at the total mass flow rate of fuel components of 7.5 kg/s, whereas the maximum fuel-based specific impulse attained ∼3000 s.