Combustion and Flame, Vol.213, 52-62, 2020
Experimental study of perforated-wall rotating detonation combustors
Perforated walls are potentially applied in rotating detonation combustors (RDCs) to stabilize combustion and perform transpiration cooling. This study involves an experimental investigation on the rotating detonation in perforated-wall combustors for the first time. Five types of walls with different hole sizes and perforated area ratios that range from 0 to 3.5% are examined to analyze acoustics and combustion characteristics, and performance of the RDC. The stable and unstable rotating detonation are both observed in the experiments, and the unstable phenomena mainly correspond to the counter two-wave rotating detonation that co-exists with the acoustic modes of the combustor. The acoustic modes are effectively suppressed by the perforated wall with area ratios over 1.75%, and the stability of rotating detonation significantly improves. The perforated walls significantly weaken the measured detonation pressure peaks and mitigate the impact of rotating detonation on the H-2 plenum, while they do not evidently reduce the specific impulse. It is proposed that the acoustic modes are excited by local high-pressure spots generated by the collision of two detonation waves, and they induce the fluctuating pressure peaks and wave velocity by affecting the H-2 injection. The perforated holes dissipate high-pressure spots, and thereby suppress the acoustic modes. (C) 2019 The Combustion Institute. Published by Elsevier Inc. All rights reserved.