Mixing and combustion of turbulent coaxial jets an application of Computational Fluid Dynamics to swirling flows

The aim of this research is gaining an insight into flow patterns in swirling burners. These are suitable for lean mixtures, because of procuring the fix position of the flame. The interaction of the two reactive confined swirling jets leads to the formation of complex patterns which are not well understood. In the present study, these flow patterns are numerically investigated using Reynolds Averaging Navier-Stokes (RANS) equations for the flow and a Probability Density Function is used for modelling the combustion. Two swirl numbers were characterised: 0.14 and 0.74. Strong swirling annular jets are responsible of an inner recirculation zone. Low swirling flows produce poorer mixture and wide flame fronts whereas strong swirling flows are precursors of mixing enhancement and thing flame fronts.