Researchers: Prof. Owen Smith, Prof. Ann Karagozian, Sophonias Teshome (grad), Jeff Wegener (grad), Cris Sevilla (grad), Aaron Sung (undergrad), Kelvin Chen (undergrad) Former Researchers: Jennifer Smolke (undergrad), Dr. Juan Rodriguez (grad), Alec Pezeshkian (undergrad), Dr. Srinivasan Dattarajan, Andy Lutomirski, Hann Mao (undergrad), Dr. Chaouki Ghenai (postdoc), Dr. Heon-Chang Kim (postdoc), Robert Lobbia (undergrad) Research Supported By: NASA Glenn Air Force Flight Test Center

	Prof. Owen Smith (right) and graduate student Srinivasan Dattarajan (left) making adustments to experiment.

This study focuses on quantifying and understanding the effects of external acoustical perturbations on condensed phase combustion processes. In the present configuration, a burning liquid fuel droplet is suspended within an essentially one-dimensional acoustic waveguide where standing waves of variable frequency and amplitude are generated by a loud speaker placed at the end of the guide. Focus has been placed in the past on normal and micro gravity experiments on excitation conditions in which the droplet is situated at either: 1) a velocity antinode (pressure node), where the droplet experiences the greatest effects of velocity perturbations, or 2) at a velocity node (pressure antinode) where the droplet is exposed to minimal velocity fluctuations. The effects of the amplitude and frequency of excitation, the droplet position relative to pressure/velocity perturbation maxima, and conditions leading to increased burning rates are identified.

This research program is designed to understand and quantify the effects of pressure oscillations on the combustion characteristics of a range of condensed fuels. Combustion of a number of alternative liquid fuels is under exploration, including ethanol, methanol, aviation fuels, and blends of aviation fuel and liquid synthetic fuel derived from coal gasification via the Fischer-Tropsch process..

Publications:

1. Droplet Combustion in the Presence of Altered Acceleration Fields via Acoustic Excitation, Teshome, S., Smith, O. I., and Karagozian, A. R.*, Western States Section/The Combustion Institute Fall Meeting, Paper 09F-82, UC Irvine, October, 2009.
   
   
2. Acoustically Driven Droplet Combustion with Alternative Liquid Fuels, Rodriguez, J. I., Mao, H.-S., Teshome, S., Pezeshkian, A., Smith, O. I., and Karagozian, A. R., 46th AIAA Aerospace Sciences Meeting, Paper AIAA-2008-1002, January, 2008.
   
   
3. Acoustically Coupled Droplet Combustion with Alternative Fuels, 3. Rodriguez, J. I., Smith, O. I., and Karagozian, A. R., 5th U.S. National Combustion Meeting, Paper G09, March 25-28, 2007.
   
   
4. Acoustic Excitation of Droplet Combustion in Microgravity and Normal Gravity, Dattarajan, S., Lutomirski, A., Lobbia, R., Smith, O. I., and Karagozian, A. R., Combustion and Flame, Vol. 144, Issues 1-2, pp. 299-317, January, 2006.
   
   
5. Acoustical Excitation of Burning Fuel Droplets in Normal Gravity and Microgravity, Dattarajan, S., Lutomirski, A., Lobbia, R., Smith, O.I., and Karagozian, A.R., AIAA Paper AIAA-2004-0955, 42nd AIAA Aerospace Sciences Meeting, January, 2004.
   
   
6. Acoustic Excitation of Droplet Combustion in Microgravity, Dattarajan, S., Lutomirski, A., Lobbia, R., Smith, O.I., and Karagozian, A. R., Paper 03F-15, Western States Section/The Combustion Institute Fall Meeting, UCLA, October, 2003
   
   
7. Droplet Combustion Control for Microgravity Experiments, Lobbia, R., Dattarajan, S., Smith, O. I., and Karagozian, A. R., Bulletin of the American Physical Society, November, 2001.
   
   
8. Control of Droplet Combustion via Acoustical Excitation, Ghenai, C., Lobbia, R., Dattarajan, S., Smith, O. I., and Karagozian, A. R., Paper 47, 2^nd Joint Meeting of the U.S. Sections of the Combustion Institute, March, 2001.
   
   
9. Acoustical Excitation of Burning Fuel Droplets, Ghenai, C., Lobbia, R., Smith, O. I., and Karagozian, A. R., AIAA Paper no. 2001-0328, 39^th AIAA Aerospace Sciences Meeting, January, 2001.
   
   
10. Numerical Simulations of Acoustically Driven, Burning Droplets, Kim, H.-C., Karagozian, A. R., and Smith, O. I., Paper 99F-50, Western States Section/The Combustion Institute Fall Meeting, October 26, 1999