Seminars & Events

Mathematics and Computer Science Division
"The Propagation of Wrinkled Turbulent Flames"

DATE: October 13, 2011 to October 13, 2011
TIME: 2:00 PM - 3:00 PM
SPEAKER: Prof. Moshe Matalon, College of Engineering Caterpillar Professor, University of Illinois at Urbana-Champaign
LOCATION: Building 240, Conference Rooms 1404 and 1405, Argonne National Laboratory
HOST: Paul Fischer and Ananias Tomboulides

Description:
We study the propagation of turbulent premixed flames using a Navier-Stokes/front-capturing methodology within the context of hydrodynamic theory. The flame is treated as a thin layer separating burned and unburned gases, of vanishingly small thickness, smaller than the smallest fluid scales. The results are applicable to the wrinkled flamelet regime of turbulent combustion. In particular, we explore the individual effects of turbulence intensity, turbulence scale, thermal expansion, hydrodynamic strain and hydrodynamic instability on the propagation characteristics of the flame. Results are obtained assuming positive Markstein length, corresponding to lean hydrocarbon-air or rich hydrogen-air mixtures. For “stable planar flames” we find a quadratic dependence of turbulent speed on turbulence intensity, modulated by the effects of thermal expansion and integral scale. Upon onset of hydrodynamic instability, corrugated structures replace the planar conformation and we observe a greater resilience to turbulence, the quadratic scaling being replaced by scaling exponents less than one. Such resilience is also confirmed by the observation of a threshold turbulence intensity below which the propagation speed of corrugated flames is indistinguishable from the laminar speed.

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