Coupling behaviour of LOx/H2 flames to longitudinal and transverse acoustic instabilities

Justin S. Hardi, Scott K. Beinke, Michael Oschwald, Bassam B. Dally

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Scopus citations


A rectangular combustor with acoustic forcing was used to study flame-acoustic interaction under injection conditions which are representative of industrial rocket engines. Hot-fire tests using liquid oxygen and gaseous hydrogen were conducted at pressures of 40 and 60 bar, which are sub- and supercritical conditions respectively for oxygen. To our knowledge, acoustic forcing has never before been conducted at pressures this high in an oxygen-hydrogen system. Examined samples of hydroxyl-radical emission imaging, collected using a high-speed camera during periods of forced acoustic resonance, show significant response in the multi-injection element flame. Transverse acoustic velocity causes shortening of the flame, concentrating heat release near the injection plane. Fluctuating acoustic pressure causes in-phase fluctuation of the emission intensity. Based on these observations, a theorized flame-acoustic coupling mechanism is offered as an explanation for how naturally occurring high frequency combustion instabilities are sustained in real rocket engines. © 2012 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
Original languageEnglish (US)
Title of host publication48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit 2012
StatePublished - Dec 1 2012
Externally publishedYes


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