DNS of auto-ignition in turbulent diffusion H2/air flames

Jeff Doom, Krishnan Mahesh

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Scopus citations

Abstract

Direct numerical simulation (DNS) is used to study auto-ignition of turbulent diffusion ames. A novel, all-Mach number algorithm developed by Doom et al1 is used. The chemical mechanism is a nine species, nineteen reaction mechanism for H2 and Air from Mueller at el.2 Simulations of three dimensional turbulent diffusion ames are performed. Isotropic turbulence is superimposed on an unstrained diffusion ame where diluted H2 at ambient temperature interacts with hot air. Both, unity and non{unity Lewis number are studied. The results are contrasted to the homogeneous mixture problem and laminar diffusion ames. Results show that auto-ignition occurs in fuel lean, low vorticity, high temperature regions with low scalar dissipation around a most reactive mixture fraction, ζMR (Mastorakos et al.3). However, unlike the laminar ame where auto-ignition occurs at ζMR, the turbulent flame auto-ignites over a very broad range of ζ around ζMR, which cannot completely predict the onset of ignition. The simulations also study the effects of three-dimensionality. Past two-dimensional simulations (Mastorakos et al.3) show that when ame fronts collide, extinction occurs. However, our three dimensional results show that when ame fronts collide; they can either increase in intensity, combine without any appreciable change in intensity or extinguish. This behavior is due to the three-dimensionality of the flow.

Original languageEnglish (US)
Title of host publication47th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition
PublisherAmerican Institute of Aeronautics and Astronautics Inc.
ISBN (Print)9781563479694
DOIs
StatePublished - 2009

Publication series

Name47th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition

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