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Characterization of an Acoustically Self-Excited Combustor for Spray Evaporation
Published in American Institute of Aeronautics and Astronautics
A combustor with a divergent inlet passage and an axially movable bluff-body flame-holder has been developed in order to enable self-excitation of highamplitude acoustic oscillations, for the purpose of enhancing the rate of evaporation of water sprays. Commercially available liquid petroleum gas is used as fuel. The acoustic pressure levels and modal contents are controlled by varying the location of the bluff-body along the axis of the combustor relative to its inlet. Locating the bluff body closer to the inlet yields higher acoustic pressure amplitudes and over a wider range of air-fuel mass ratios. The sound pressure level is found to increase with increase in mass flow rate of air and airfuel mass ratio. The excitation modes are found to shift from the fundamental to the first harmonic for certain air-fuel mass ratios for a given mass flow rate of air. Measurement of pollutant emission levels indicate low CO concentrations in the presence of high-amplitude acoustic oscillations, but slightly higher NOx concentration than at low acoustic amplitude conditions. When high sound pressure levels are excited in the combustor, the heat transfer due to water cooling of the combustor walls and across the walls of the tailpipe increased considerably - up to 40% for an increase in SPL from 145 dB to 160 dB. Water spray evaporation experiments are performed with low and high sound pressure levels of acoustic excitation, for different water injection rates over a range of mass flow rates of fuel and air. For a given mass flow rate of air and fuel, it is found that the water evaporation rate increased significantly above a certain threshold acoustic pressure - up to 107% for a sound pressure level of 156 dB, despite the considerable increase in heat losses due to the acoustic oscillations. © 2003 by Dr. R. I. Sujith & Dr. S. R. Chakravarthy.
About the journal
JournalData powered by Typeset41st Aerospace Sciences Meeting and Exhibit
PublisherData powered by TypesetAmerican Institute of Aeronautics and Astronautics
Impact Factor1.868
Open AccessNo
Citation Styleunsrt
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