Hypersonic Combustion by Standing Detonation Using Counter-Supersonic Flow

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1.Extension of the low pressure section of the present detonation driven shock tunnel resulted in longer test time from 0.7 ms to 2.0 ms, although static pressure at the nozzle exit decreases by 20 %.2.OH extinction measurement revealed that duration of supersonic air flow which is not contaminated by the driver gas is about 0.5 ms, which is much less than the theoretical value of 5 ms.3.By using the shock tube in which helium and oxyhydrogen are initially introduced in the high pressure and low pressure section, respectively, it was possible to generate a combustible supersonic flow with static pressure of 70 kPa, static temperature of 600 K, and mach number of 1.2 without spontaneous ignition of the mixture.4.In the case that detonation is introduced perpendicularly to the direction of the combustible supersonic flow, it was found that the diffracted wave front is decoupled into a shock and reaction front. After reflection of the shock front at the bottom surface of the test section, detonation is re-initiated and then propagates upstream and downstream.5.Apparent velocity of detonation in a supersonic flow is faster in the upstream area and slower in the downstream than CJ-velocity by speed of the supersonic flow.6.Smoked foil record shows that cellular structure is deformed in the direction of the supersonic flow. Experimental value of the aspect ration of the cell agrees well with the calculated one based on the CJ-velocity, the velocity of the transverse wave, and the speed of the supersonic flow.