Tese: Reynolds-Average Navier-Stokes Modelling of a Turbulent Lean Premixed Combustor
Aluno(a) : Alain Prais Neviere CoimbraOrientador(a): Luis Fernando Silva
Área de Concentração: Termociências
Data: 19/09/2019
Link para tese/dissertação: http://doi.org/10.17771/PUCRio.acad.48824
Resumo: Lean premixed turbulent swirling flames are found in many engineering systems, such as gas turbines and jet engines. This work aims to numerically study flame regimes, representative of such systems, stabilized in a laboratory scale burner. The state of the art of the numerical studies concerning these types of flames is reviewed, with respect to Reynolds-Averaged Navier- Stokes and Large Eddy Simulations. A turbulent, isothermal flow study is performed within the radial swirler and the combustion chamber. The impact of different turbulence models, mesh refinement levels and boundary conditions on the swirl number and overall flow structure is investigated. The results show that the three tested turbulence models yield similar results, with respect to the obtained flow field, whereas the mesh refinement level and slip wall boundary condition alter the swirl number significantly. Using Reynolds-Averaged Navier-Stokes transport equations, closed by the realizable k − epsilon model, coupled with a two-equation premixed combustion model for methane/air mixtures, two stable combustion regimes are analyzed. These regimes correspond to the Outer Recirculation Zone flame (M-flame) and an unstable regime, which occurs at the transition between the V-flame and tornado-flame. The flow structure is characterized in terms of velocity fields, turbulence and combustion properties. A reaction progress variable comparison is also performed, using existing experimental results, yielding qualitatively similar results for both studied regimes