Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published September 2013 | Supplemental Material
Journal Article Open

Numerical modeling of sooting tendencies in a laminar co-flow diffusion flame

Abstract

The intent of this paper is to predict the experimental sooting tendencies [Combust. Flame 148 (2007) 210–222] from a detailed chemical mechanism with relatively low computational cost, using a flamelet-based model. Towards that goal, direct numerical simulations using finite-rate chemistry are conducted on a methane–air confined axisymmetric co-flow diffusion flame to provide reference data. Soot transport model is excluded in these direct simulations for both simplicity and to be unbiased from the choice of soot model used. Sooting tendencies are estimated exclusively from the increment of polycyclic aromatic hydrocarbon (PAH) dimer production rate along the centerline when the flame is doped. Calculations using the conventional steady state diffusion flamelet model are performed and this model is shown to be inadequate in reproducing the correct species profiles on the centerline of the flame, where the sooting tendencies are defined. The main reason for the failure of the conventional flamelet model is due to the neglect of multidimensional convection and diffusion effects. In an effort to overcome these deficiencies, a new numerical framework based on modified flamelet equations is proposed. The flamelet equations are rederived for species mass fractions along the centerline of the co-flow diffusion flame considered. These equations take into account the effects of multidimensional diffusion and convection of species in mixture fraction space due to non-unity Lewis numbers. The modified flamelet equations take as input the temperature, convective velocity, and scalar dissipation rate profiles calculated from the direct simulation of the diffusion flame. The numerical sooting tendencies for both non-aromatic and aromatic test species are then calculated using the PAH dimer production rate generated from the flamelet solutions doped by the test species. These first numerically-computed sooting tendencies are derived from a detailed chemical kinetic mechanism and are in good agreement when compared to experimental values.

Additional Information

© 2013 The Combustion Institute. Published by Elsevier Inc. Received 17 December 2012; Received in revised form 24 February 2013; Accepted 29 March 2013; Available online 7 May. 2013. The authors thank Kevin Shi for his initial help on this project. The authors gratefully acknowledge funding from the U.S. Department of Energy-Basic Energy Sciences (DE-SC006591).

Attached Files

Supplemental Material - mmc1.zip

Files

mmc1.zip
Files (87.0 kB)
Name Size Download all
md5:68c33b31d7640655c7644fb127b026c8
87.0 kB Preview Download

Additional details

Created:
August 22, 2023
Modified:
October 24, 2023