LAMINAR FLAMELET MODELING OF TURBULENT PREMIXED COMBUSTION

Laminar flamelet method (LFM) based prediction procedures for turbulen t premixed combustion are presented. Two different approaches are inve stigated. In one case, the standard eddy dissipation concept (EDC) is used as the turbulent combustion model and the laminar flamelet model is applied as a post-processor for subsequent nitrogen oxide predictio ns. In the second approach, however, a higher predictive potential is achieved by employing the LFM as the turbulent combustion model. Predi ctions are compared with experiments for two different turbulent premi xed flame configurations, namely for an essentially parabolic, laborat ory flame, and a strongly swirling, recirculating flame of an industri al gas turbine burner. Results show that a substantial increase of pre dictive capability compared to more traditional methods is achieved by the flamelet method, not only for laboratory flames, but also for pra ctical gas turbine applications. For the latter, the classical order o f magnitude analysis suggests that the combustion occurs outside the l aminar flamelet regime. Despite this, laminar flamelet predictions sho w relatively good agreement with experimental data, supporting argumen ts that such modelling is appropriate beyond the classical laminar fla melet combustion limits defined in the Borghi diagram. (C) 1998 Elsevi er Science Inc. All rights reserved.