ID#: 111
Abstract Title: Unstable Explosion Flames and Acoustic Oscillations
Session Title: Acoustic Phenomena
Session Date: 7/31/01
Session Start Time: 2:00 PM
Contributing Author: Woolley, R.
Organization: University of Leeds
Country: U.K.
Authors: D. Bradley, C.G.W. Sheppard, R. Woolley
Short Abstract: Studies of instabilities in spherical gaseous explosion flames are described. It is shown that a decrease in Markstein number leads to large increases in the burning rate, particularly in the later stages of the explosion. The increase is associated also with the generation of strong acoustic oscillations. Experimentally, pressures were recorded during explosions of hydrogen - air and iso-octane - air at 0.5 MPa and different equivalence ratios. Burning velocities much higher than the laminar values were observed for the lean hydrogen and rich iso-octane mixtures. This is attributed to the rapid generation of a cellular flame structure, due to Darrieus - Landau instability. The interaction of pressure waves with the cellular structure can introduce further flame wrinkling through Taylor instability. Fan induced turbulence in the bomb showed that turbulence eventually suppresses such instabilities