Interplay between background turbulence and Darrieus-Landau instability in premixed flames via a model equation

The effect of the Darrrieus Landau instability on a premixed flame in a turbulent environment is investigated using a model equation known as the Michelson Sivashinsky equation, in both one and two dimensions. The equation is externally forced with noise representative of weak turbulence in the flow and the response of the flame to both unstructured and structured noise is examined. It is found that for a given noise intensity there exists a threshold domain size, beyond which the instability amplifies the perturbations due to noise and causes the formation of wrinkles on the flame surface, leading to an increase in the propagation velocity. Scaling laws are proposed for the increase in propagation velocity with variations in noise intensity and a bifurcation parameter, which includes the effects of parameters such as the domain size, equivalence ratio and reaction rates. Self fractalization of the flame is observed at high noise intensities. Effects of the scale of noise, analogous to the scale of turbulence, are also examined and a resonant behavior is found to exist at certain scales. In the two dimensional case, cellular structures, similar to the ones observed experimentally on expanding spherical flames, are observed on the flame surface. Scaling laws similar to the one dimensional case are proposed.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2010

Author dc:creator

• Fogla, Navin

Contributors dc:contributor

• Matalon, Moshe

• Michelson Sivashinsky equation
• Darrieus–Landau instability
• turbulent flames
• self-fractalization

Statement dc:rights

• Copyright 2010 Navin Fogla

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/16182

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/16182