Study On Reaction Mechanisms And Numerical Simulation Of Three-Way Catalytic Converter

Nowadays emission regulations are getting stricter and stricter, three-way catalytic converter is the main technology for dealing with car emissions and its research and design should be paid more attention. The design of a three-way catalytic converter is a complex process involving the consideration of different physical and chemical parameters of both the catalyst and the exhaust gas. In this paper these were analyzed and studied from the point of view of chemical kinetics.After doing some investigations on the technology of three-way catalytic conversion, the factors influencing the performances of three-way catalytic converter were generalized such as flow state in converter, temperature distribution, exhaust gas species, converter's design and catalyst's property. Mathematical model was established by combining different chemical reaction mechanisms with the governing equations. The results from numerical calculations had good agreement with experimental data, which proved the accuracy of the model. Moreover the advantages and defects of different mechanisms were compared and analyzed, which would be of great reference to modify or develop better reaction mechanisms then to increase the computational accuracy of the model.In order to investigate the catalytic properties of converter and predict its performance, a mathematical model of a single channel of the monolith was built. The model included not only a description of 2-D flow field but also a detailed chemical reaction mechanism for the first time. The flow field model and chemical reaction mechanism was coupled by using CFD software. Numerical simulation was made on different exhaust gas components and temperature. Results were consistent with experimental data which proved that the mathematical model was correct, which put forward a new investigation content for the numerical simulation of three-way catalytic converter's working process. In addition, the mass distribution of gas components in the channel and the coverage variation of different components on catalyst surface were obtained, from which the interaction of the reaction flow field and chemical property of catalyst surface could be obtained and could provide a guide for the preparation and coating of the catalyst.