Multi-Phase Combustion and Transport Processes Under the Influence of Acoustic Excitation
Technical Report,02 Jan 2011,31 Dec 2013
AFRL Edwards AFB United States
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This experimental study examined the coupling of acoustics with reactive multiphase transport processes and shear flows. The first portion of this dissertation deals with combustion of various liquid fuels when under the influence of externally applied acoustic excitation. For this study, an apparatus at the Energy and Propulsion Research Laboratory, UCLA, used a horizontal waveguide to create a standing acoustic wave, wherein burning fuel droplets were positioned near pressure nodes within the waveguide. Alcohol fuels ethanol and methonal as well as aviation fuel replacements Fischer-Tropsch FT synfuel and an FT blend with JP-8 were studied here. During acoustic excitation, the flame surrounding the droplet was observed to be deflected in a manner consistent with the direction of a theoretical acoustic radiation force, analogous to a buoyancy force, acting on the burning system. The second portion of this dissertation utilized a similar, but more advanced facility which was recently constructed at the Air Force Research Laboratory, Propulsion Directorate RQR. These experiments explored the interaction between acoustics and nonreactive shear-coaxial jets under high chamber pressure, acoustically resonant conditions, using liquid nitrogen as the inner jet and gaseous helium as the outer jet.