Combustion and Flame, Vol.136, No.3, 327-350, 2004
Hybrid finite-volume/transported PDF simulations of a partially premixed methane-air flame
A hybrid finite-volume (FV)/transported probability density function (PDF) method is used for the simulation of a partially premixed flame with detailed chemistry. The FV code is implemented to handle detailed chemistry implicitly with no subgrid closure. A partially premixed methane-air flame is simulated to illustrate the need for closure. The PDF scheme is then substituted to handle the species transport using a subgrid mixing model. The algorithmic modifications to the PDF code are discussed in the context of a generalized structured grid solution technique. A multi-step particle transport algorithm is used to eliminate grid dependence of the time step. A detailed chemistry mechanism (GRI-2.11) is handled using in situ adaptive tabulation. It is shown that with simple modifications, the Interaction by Exchange with the Mean mixing model is able to predict the flame quite accurately. Mean profiles and conditional means obtained using the 49-species GRI-2.11 and 53-species GRI-3.0 mechanisms and the 16-species Augmented Reduced Mechanism are compared with the experimental data from the Sandia D flame. It is shown that with the mixing model, good agreement with the experimental data is achieved. Also the effect of the value of the mechanical-to-scalar time-scale ratio used in the mixing model is analyzed. The effect of the model constants in the dissipation equation for the turbulence model and the effect of radiation on flame predictions are also discussed. (C) 2003 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
Keywords:methane-air flame;finite-volume method;Lagrangian particle method;hybrid scheme;ISAT;GRI mechanism;partially premixed flames;numerical simulations