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ANALYZING SELF-IGNITION IN RAPIDLY COMPRESSED TURBULENCE

Guillaume Lodier
CORIA - CNRS & INSA Rouen, BP 8, 76801 Saint-Etienne-du-Rouvray, France

Pascale Domingo
CORIA - CNRS & INSA Rouen, BP 8, 76801 Saint-Etienne-du-Rouvray, France

Luc Vervisch
CORIA - CNRS & INSA Rouen, BP 8, 76801 Saint-Etienne-du-Rouvray, France

Abstrakt

A method to estimate the propagation speed of an ignition front in Direct Numerical Simulation (DNS) is discussed. It is based on the time evolution of perfectly stirred reactors starting at various fresh-gas ignition temperatures. The proposed approach is applied to DNS of a rapid compression machine, in which the mixture composition is homogeneous, but the temperature distribution is non-uniform due to heat-transfer at wall. The two expected distinct ignition regimes are reported, one where combustion propagates at the speed of sound or even above and occurring over a large portion of the combustion chamber, with a strong and sudden pressure increase; another one, much more localized in space and with a flame propagation pertaining to a deflagration mode.