Supersonic Exhaust from a Rotating Detonation Engine with Throatless Diverging Channel

Kotaro Nakata, Kosei Ota, Shiro Ito, Kazuki Ishihara, Keisuke Goto, Noboru Itouyama, Hiroaki Watanabe, Akira Kawasaki, Ken Matsuoka, Jiro Kasahara, Akiko Matsuo, Ikkoh Funaki, Kazuyuki Higashino, James Braun, Terrence Meyer, Guillermo Paniagua

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Converging–diverging nozzles are common in rocket engine systems to increase the exhaust velocity and improve thrust performance. In this study, we focused on the acceleration of subsonic burned gas without a structural throat via detonation to realize a simple and compact engine. We developed and tested a rotating detonation engine (RDE) without a throat and with a diverging channel (constant diverging angle α 5 deg). Gaseous C2H4 and O2 were used as the propellants, and the mass flow rate ranged from 62 to 134 g∕s in the combustion tests under low back-pressure conditions. We measured pressure and thrust, as well as high-speed imaging of self-luminescence of the combustion and imaging of the exhaust plume. The pressure at the exit was less than one-fifth of the maximum pressure in the RDE, significantly below the value for a sonic flow. The results suggested that the exhaust flow was supersonic, with values up to Mach 1.7, without the need of a converging section within the engine. In addition to the estimated Mach number from the measured pressure, the exhaust plume images coherently indicated the existence of supersonic exhaust.

Original languageEnglish
Pages (from-to)4015-4023
Number of pages9
JournalAIAA journal
Issue number7
Publication statusPublished - 2022

ASJC Scopus subject areas

  • Aerospace Engineering


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