Laminar flamelet modelling of turbulent premixed combustion

Abstract Laminar flamelet method (LFM) based prediction procedures for turbulent premixed combustion are presented. Two different approaches are investigated. 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 predictions. In the second approach, however, a higher predictive potential is achieved by employing the LFM as the turbulent combustion model. Predictions are compared with experiments for two different turbulent premixed flame configurations, namely for an essentially parabolic, laboratory flame, and a strongly swirling, recirculating flame of an industrial gas turbine burner. Results show that a substantial increase of predictive capability compared to more traditional methods is achieved by the flamelet method, not only for laboratory flames, but also for practical gas turbine applications. For the latter, the classical order of magnitude analysis suggests that the combustion occurs outside the laminar flamelet regime. Despite this, laminar flamelet predictions show relatively good agreement with experimental data, supporting arguments that such modelling is approppriate beyond the classical laminar flamelet combustion limits defined in the Borghi diagram.