Combustion analysis on a CFM56-3 engine

• Autor(a) principal: Neves, Kevin Azevedo das
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.6/8325
• topic: Cfd; Cfm56-3; Combustão; Converge.; Jet-A; Modelo; Turbulência; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Aeronáutica

The more fuel efficient an engine is, the less fuel is needed to get from point A to point B and the less Greenhouse gases will be produced. In spite of being a major source of carbon dioxide, gas turbine engines lead the aircraft propulsion systems globally and will probably continue for the next decades. Thus, one of the most immediate ways to go green on the skies is by advancing their performance. Nontheless, GTE’s are one of the most complex engineering problems, as they rely on hundreds of parameters that can be tweaked and result in a better configuration. However, we have computers and softwares that allow us to test engine concepts. This study consisted in a numerical analyses of the combustion of Jet-A in the annular combustor of the CFM56-3 engine, through two different turbulence models. The geometry used was ¼ of the engine constructed by Jonas Oliveira by performing a 3D scan on a real size combustor. This geometry was imported and prepared in a CFD software, CONVERGE Studio, where the case setup was configured. The simulation itself was run on the main software CONVERGE installed on a multi-core high performance machine. The final goal of this study was to compare the behavior of each turbulence model when studying the performance of annular combustors similar to the most popular turbofan engine’s. The turbulence models chosen were the standard ??-?? and the standard ??-?? and also a set of models were defined to simulate the injection of fuel through a parcel spray and, therefore, better predict the flow inside the combustor. To compare the simulation results, six main parameters were analysed: Turbulent Kinematic Energy (??); Turbulence Dissipation Rate (??); Specific Turbulence Dissipation Rate (??); Turbulent Length Scale (??); Friction Velocity (??*); and the dimensionless wall distance (??+). Both models demonstrated a similar behavior in all the parameters, along the runtime. The results were all within the same order of magnitude, although the absolute values have shown a considerable difference. The simulation outputs were considered acceptable after comparing quantitatively the exhaust parameters, and qualitatively a temperature and TKE contour with two previous works with similar setup conditions. Any turbulence model was judged better than the other, due to the complexity involved in such a study, but only considered different.