Effect of high-pressure detonation products on fuel injection and propagation characteristics of detonation wave

The effect of high-pressure detonation products on fuel injection and propagation characteristics of detonation wave has been investigated in the form of ion voltage by varying the equivalence ratio (ER), air mass flux, and operation duration with hydrogen-air mixtures. It has been shown experimentally that the ion voltage decays gradually during the initial stage of rotating detonation wave (RDW). The attenuation of ion voltage is a general phenomenon, and the decay rate of ion voltage and its peak value of the trough state are related to the equivalence ratio and air mass flux. The analysis of interaction between the combustor and hydrogen plenum indicates that the feedback of high-pressure detonation products leads to the attenuation of ion voltage. In addition, the long-duration tests show that the ion voltage will recover to a steady state with the extension of reaction time, when the purgation (products leaving plenums) of detonation products is greater than feedback (products entering plenums) of detonation products in the hydrogen plenum. The recovery of ion voltage starts earlier at the higher equivalence ratio and air mass flux, and the peak value of ion voltage in the steady state also increases with the increase of equivalence ratio and air mass flux. A low frequency oscillation about 10–12 Hz occurs in the RDW at some operation conditions. This low frequency oscillation is related to the interaction between the combustor and hydrogen plenum, and can be eliminated by either increasing the equivalence ratio or decreasing the air mass flux.