Three-Dimensional Numerical Simulation Of Flow Fields In The Catalytic Converter

Catalytic converter is an assembly to effectively reduce the poisonous emissions from internal combustion engine. In order to meet the increasingly stringent automotive emission standards, the catalytic converter not only has high conversion efficiency and a long durability but also has low light-off temperature and good flow features. The complicated flow, heat and mass transfer in the catalytic converter are the most important factors. In one side, the asymmetry of flow beget vortex and the separation of airflow which is the cause of pressure losses. And in the other side, it contributes the asymmetry of temperature .Catalyzer become invalidation easy in the areas where the temperature is too high, but in the low temperature place, the catalyzer can not be made the best of using. And, at radial converter, the asymmetry of temperature contributes increasing in grid of temperature and thermal stress easily, that engender thermal deformation and mangle the converter. Consequently it is necessary to understand the flow behavior inside the converter and optimize the configuration.Now, the mostly important method in study flows in catalytic converter is simulated the flowing using Computational Fluid Dynamics (CFD) commercial code. The mostly works are investigating the influence of the configuration and structure of the canister and substrate on the flow distribution and pressure loss. Up to this present, lots of intensive researches have been done by domestic and overseas academicians, and the technology has been maturated. But all of these are from the point of view of scientific research. In the process of research and development, want to take a numerical simulation and analysis for an exploring product, through these ways to provide a common source for Product Development engineers. So the simulation and analyze must be based on the engineering test procedure. This procedure makes detail requirements on every step of steady state analysis for catalytic converter gas flow distribution.In this dissertation , a computational fluid dynamics (CFD) code was used to simulate the three-dimensional steady flow in a catalytic converter with eccentric inlet-cone without heat transfer and chemical reaction in substrate .In this simulation ,the computational mesh are used hexahedral mesh. The distribution and the pressure loss of the flow within this new type catalytic converter were investigated. The focus of this paper is concentrated on the generation of hexahedral mesh. Based on the strict procedure, the effective simulate result can be used as reference for developing a new type of catalytic converter.