RESUMO

Improved mixing of a jet with its surroundings is of interest in many applications that demand enhanced combustion of injected fuel and background oxidizer (in e.g. SI engines, ram- and scramjet engines and jet flame afterburning). In this context, there is a great interest in understanding and predicting the local nature of jet instabilities and their non-linear development in space and time. The vorticity dynamics and the mixing, determine the heat release pattern within the flame, and by understanding these processes it is possible to select optimal conditions to improve jet combustion. Here, we investigate non-reactive and reactive round jets using Large Eddy Simulation (LES). The LES equations are closed using the one equation eddy viscosity and the localized dynamic kinetic energy subgrid models, whereas the combustion is modeled by a truncated Arrhenius chemistry model. Grid refinements have been performed to study the influence of different grids on the solution. For the nonreacting jet good agreement with experimental data is found, whereas for the reacting jet the flow field is reasonably well predicted, but less good agreement is found for the thermodynamic quantities.