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为研究汽车尾气催化器在汽车启动过程中的温度场 ,建立了描述催化器内复杂物理化学过程的二维非稳态数理模型。利用热流体计算软件 Phoenics1.4对模型进行了稳态与非稳态的计算 ,分析了尾气流量、载体上贵金属活性中心表面积等对催化器温度场及其转化效率的影响。为验证模型的可靠性 ,在实际的发动机台架上研究了国产催化器内的温度场及其转化效率。研究表明 :加大尾气流量 ,增加载体上贵金属活性中心表面积等措施可加快催化器的起燃速度 ;但当催化器接近稳态时 ,尾气流量越大 ,催化器的转化效率反而越低
In order to study the temperature field of automobile exhaust catalyst during the startup process of automobile, a two-dimensional unsteady mathematical model describing the complex physico-chemical process in the catalyst was established. The thermodynamic fluid calculation software Phoenics1.4 was used to calculate the steady state and unsteady state of the model. The influence of the exhaust gas flow rate, the active center area of precious metal on the catalyst temperature field and its conversion efficiency was analyzed. In order to verify the reliability of the model, the temperature field and its conversion efficiency in the domestic catalyst were studied on the actual engine bench. The results show that increasing the tail gas flow rate and increasing the surface area of the precious metal active center can speed up the light-off of the catalyst. However, when the catalyst is close to the steady state, the larger the tail gas flow rate, the lower the catalyst conversion efficiency