Large Eddy Simulation of Combustion Systems

This paper presents a model that is suitable for computing unsteady gaseous combustion with finite rate chemistry. Large eddy simulation is used to model turbulence. The Reynold stress terms are modelled by a linear combination of the scale-similarity and eddy-dissipation models while the cross terms are of the scale-similarity type. For the chemical reactions, a 3-step mechanism is used for methane oxidation and the extended Zeldovich and N₂О mechanism are used for NO formation. The combustion model is a hybrid model of the Arrhenius type and a modified eddy dissipation model to take into account the effects of reaction rate, flame stretch and turbulent intensity and scale. Numerical simulations of Burke-Schumann flame in a 2-D planar geometry using the model shows up some interesting structures and wave dynamics.