Modelagem tridimensional da combustão em um motor adaptado com pré-câmara

Abstract

With the advancement of technology, numerical methodologies have been applied in different areas of engineering, increasingly optimizing complex projects, such as internal combustion engines. This work aims to develop a computational methodology for the optimization of the implementation of a pre-chamber of homogeneous mixture combustion in a spark internal combustion engine. This prechamber is a separate volume from the main chamber, where combustion is initiated. The two chambers are connected by one or more interconnecting holes, responsible for the exchange of fluid and energy between these volumes. To achieve the general objective the methodology of this work, the first was constructing the computational domain from the geometry of the physical motor, as well as obtaining the valve diagram of the same. Using the GT-Suite software, it was possible to develop a model from the experimental data, capable of generating the initial and contour conditions, necessary for the three-dimensional simulation. In the modeling of the system only one cylinder is considered. For the three-dimensional simulation, the CONVERGE program was used, and the three-dimensional analysis was done in Paraview software. In the next step, with the internal geometry implemented, the mesh is generated and the mesh tests are performed, in order to obtain the results in the three-dimensional model that can be compared with a zerodimensional model developed in the CTM (Mobility Technology Center) and the experimental data, validating the methodology. The analyzed parameters for validation of the three-dimensional model are the pressure in the cylinder, the amount of fuel consumed per cycle and the amount of heat released. The pressure results showed a good correlation between the models and the experimental data, after making some corrections in the three-dimensional model. In addition to these data, the flow of the mixture inside the engine and its impact on the flame propagation were analyzed. In addition to the current design geometry, two geometry proposals for the pre-chamber were simulated and compared with the initial design. With the analysis of their heat release and the duration of the combustion it is observed that the proposals had a similar behavior to the initial design