Research On Structure And Its Flow Filed In Automotive Catalytic Converter

The research object of this thesis is the very important device for engine exhaust system used to reduce harmful emissions of auto, catalytic converter. The flow in the catalytic converter is very complex, including complicated flow, heat and mass transferred, chemical reaction. The asymmetry of flow begets vortex and the separation of airflow which cause of pressure losses and the catalyst can not be fully used in some area that not only be bad for energy saving and environmental protection, but also reduce the conversion rate and useful life of catalytic converter. The temperature distribution non-homogeneously can lead to the carrier radial direction gradient of temperature to increase, produce the thermal stress, make the carrier deformation and even damage.Based on the above-mentioned problems, this thesis, by the simulation analysis to the fluid on the flow characteristics in the catalytic converter internal flow field, take reducing the pressure losses and improving the uniformity of flow field as the goal, using Pro/E software to establish entity model for the internal flow field of the catalytic converter, through the CFD numerical simulation method on the platform of Fluent software, take the simulation analysis to the different parameters of airspeed, inlet little pipe, inlet cone, position of the carrier, outlet cone of the catalytic converter and discuss the influence of different parameters to the internal flow field of the catalytic converter. By the addition of flow guide device, take the optimization and improvements to the structure of the catalytic converter.The simulation results prove that all the change with the parameters that above mentioned have certain effect to the pressure loss and flow uniformity of catalytic converter internal flow field, and the change with the angle of inlet cone of the catalytic converter have the biggest effect to the pressure loss and flow uniformity of catalytic converter internal flow field. Adding flow guide device have in the position of inlet cone has little effect to the pressure loss of flow field and can improve flow uniformity of flow field effectively.Through the simulation analysis to the internal flow field of catalytic converter, the influence characteristics of different parameters to the internal flow field of the catalytic converter can be obtained, that can provide reliable theory basis for improving work efficiency and prolong the working life of the catalytic converter.