A Spatially Developing One-Dimensional Turbulence (ODT) Study of Soot and Enthalpy Evolution in Meter-Scale Buoyant Turbulent Flames

Abstract

The interaction between soot and enthalpy evolution in a buoyant turbulent flame, exhibiting key attributes of a fire, is studied using a novel approach. This approach is based on a spatially evolving form of the one-dimensional turbulence (ODT) model that resolves the full range of scales, in a single spatial dimension, from the scale of the plume evolution to that of the soot layers. The model is compared with limited experimental data available. The evolved flow field of a meter-scale flame is then analyzed both in terms of conventional spatial averages and conditional averages. The conditional moments of the terms in the soot and enthalpy evolution equations are analyzed to elucidate the balance between the large-scale evolution (advective terms), the source terms, and the turbulent mixing (dissipative terms). The results show the significant influence of the mixture evolution on the transport of soot relative to the flame (in mixture-fraction space).

Keywords:

• Conditional moments
• Diffusion flame
• One-dimensional turbulence
• Radiation heat transfer
• Soot
• Stochastic modeling
• Turbulent flame

ACKNOWLEDGMENTS

Support for this effort was provided by the Sandia Engineering Sciences Research Foundation and the Sandia Physics & Engineering Models program, as well as by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences. This research was performed at Purdue University, West Lafayette, Indiana, and Sandia National Laboratories, a multi-program laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the United States Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94-AL85000. Simulations were performed at Sandia National Laboratories on the Rogue Linux Cluster. Discussions with Dr. Scott Wunsch of the Combustion Research Facility at Sandia National Laboratories and Prof. Steven Frankel of Purdue University are gratefully acknowledged. Special thanks are offered to Dr. David Lignell and Dr. David Glaze for thorough reviews of the manuscript.

Notes

Units are in kg, m, s, kmol, kcal, and K.