Comparison of LES Models Applied to a Bluff Body Stabilized Flame

Present-day demands on combustion equipment are increasing the need for improved understanding and prediction of turbulent combustion. Large Eddy Simulation (LES), in which the large-scale flow is resolved on the grid, leaving only the small-scale flow to be modeled, provides a natural framework for combustion calculations as the transient nature of the flow is resolved. In most situations, however, the flame is thinner than the LES grid, and subgrid modeling is required to handle the turbulence-chemistry interaction. Here, we examine the predictive capabilities and the theoretical links be-tween LES flamelet models, such as the G-equation model (G-LES), and LES finite rate chemistry models, such as the Thickened Flame Model (TFM-LES), the Partially Stirred Reactor model (PaSR-LES), the Eddy Dissipation Concept (EDC-LES) model, a Presumed Probability Density Function (PPDF-LES) model and the Implicit LES (QL-LES) model. The models are described, and theoretical links between these are discussed in terms of the turbulent flame speed and flame thickness. In addition, the different models are used to study a bluff-body stabilized flame and the resulting predic-tions are compared with experimental data for two operating conditions. I. Introduction and Background Few have escaped the recent year’s intense debate on climate change. Several reports highlighting how anthropo-logical activities threaten to create a significant change of the global climate has received extensive media attention. This has led to tougher demands from both authorities and consumers for manufacturers to increase energy efficien