LES modelling of nitric oxide (NO) formation in a propane-air turbulent reacting flame

Large Eddy Simulation (LES) technique is applied to investigate the nitric oxide (NO) formation in the propane-air flame inside a cylindrical combustor. In LES a spatial filtering is applied to the governing equations to separate the flow field into large scale eddies and small scale eddies. The large scale eddies which carry most of the turbulent energy are resolved explicitly while the unresolved small scale eddies are modelled. A Smagorinsky model with model constant Cs = 0.1 as well as a dynamic model has been employed for modelling of the sub-grid scale eddies, while the nonpremixed combustion process is modelled through the conserved scalar approach with laminar flamelet model. In NO formation model, the extended Zeldovich (thermal) reaction mechanism is taken into account through a transport equation for NO mass fraction. The computational results are compared with those of the experimental results investigated by Nishida and Mukohara [1] in co-flowing turbulent flame