Large Eddy Simulation of Bluff Body Stabilised Premixed Flames Using Flamelets

Abstract

Large Eddy Simulations of an unconfined turbulent lean practical flame stabilised behind a bluff body burner are computed using structured and unstructured numerical solvers. Unstrained flamelets are used as the sub-grid scale combustion closure using constant and dynamic formulations to model the flame curvature parameter βc. The model uses a presumed probability density function to calculate the filtered reaction rate. The aim of this study is to determine the numerical set-up that provides the most reliable results for the flame that is furthest from blow-off conditions (A1). This work will lead to modelling the flame closest to blow-off (A4) and the flame at blow-off conditions, since these flames are highly unstable. Comparisons will be drawn with experimental data obtained using PIV, OH chemiluminescence and OH-PLIF techniques.