Engine LES with fuel-spray modeling

• Autor(a) principal: Ribeiro, Mateus Dias [UNESP]
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/127949; http://www.athena.biblioteca.unesp.br/exlibris/bd/cathedra/10-09-2015/000846822.pdf
• topic: Motores de combustão interna; Atomização; Fluidodinâmica computacional; Aerossois; Computational fluid dynamics

The internal combustion engine is the major energy source of automobiles and is of large importance for the energy sector worldwide. As problems related to exaggerated pollutant and greenhouse gases emissions emerged, the development of models to correctly describe the physical phenomena taking place inside the combustion chamber of engines became relevant. Thus, in the first part of this work the open source CFD library OpenFOAM with modules developed at the University of Duisburg-Essen was used to investigate the effect of the crevice volume on the performance of the combustion in port fuel injection spark ignition engines. The LES (large eddy simulation) simulations were validated against high speed flame visualization obtained from the Duisburg optical engine, which showed the presence of a luminous front inside the top land crevice that could be a wrinkled flame. The presented results showed good qualitative agreement with the experimental data, which allowed the conclusion that in the case of the Duisburg engine, the flame indeed penetrates into the crevice volume. Furthermore, a study on fuel sprays was performed, since this is a very promising trend related to modern engines. Special attention was given to the phenomena of momentum exchange, droplet breakup, evaporation and mixture from the test case Spray G provided by the Engine Combustion Network (ECN). The processes of droplet breakup and evaporation were investigated and simulated, being the results interpreted according to the models used. The penetration length was validated against experiments and good agreement was obtained. Finally, a mesh sensitivity study was performed and the results presented and discussed