Understanding Soot Growth Turbulent Nonpremixed Glames via Direct Numerical Simulation and Lagrangian Statistics
October 29, 2012
2:00 p.m.
Dr. Fabrizio Bisetti
Abstract
Particulate emissions from combustion devices endanger population health and have adverse effects on the environment. The formation and growth of soot in n-heptane/air turbulent non-premixed jet flames is investigated by performing a set of three-dimensional Direct Numerical Simulations (DNS) at varying Damkoehler number.
The soot dynamics are simulated with a method of moment and the resulting advective/reactive equations for the evolution of the moments are solved with a particle-based Lagrangian method (Koumoutsakos Ann. Review Fluid Mech. 2005), which has excellent stability and accuracy. The Lagrangian solver is coupled to the Eulerian flow solver for the velocity and reactive scalar fields.
Building upon recent work by our group and collaborators (Bisetti et al. Combust. Flame 2012), it is shown that the soot growth process is strongly affected by the intermittent turbulent mixing field as described by Lagrangian statistics. Furthermore, the soot growth rate and soot yield are related to the turbulent meandering of soot particles across the flame as well as temperature and composition history.