发动机三元催化器数值分析
摘要为了分枂某发动机三元催化器载体前端气流分布情冴文章对该催化器迚行了CFD数值分枂。计算模式采取稳态计算计算时分别考虑每个气缸排气当一个缸排气歧管设定为排气时其他缸的排气歧管设定为关闭状态。 通过计算得到了载体前端的速度均匀性系数由于4个缸分别排气时速度均匀性系数均大于085满足评价指标因此该催化器满足设计要求。
关键词发动机三元催化器速度均匀性系数 多孔介质
Numerical Analysis on Three-way Catalystof Engine
Abstract: In order to analyze gas flow distribution in front end of three-way catalyst substrate, CFD numerical analysis wascarried out in the paper Steady mode was chosen as the calculation mode Each cyl inder exhaust is considered respectively incalculation When a manifold of one cyl inder is set at exhaust,manifolds of other cyl inders are set at close mode By calculatingthe velocity uniform index of front end of substrate was gained Al l indexes was bigger than 085 when four cyl inders exhaustedrespectively The result met evaluation index, and this catalyst met design requirements
Key words Engine;Three-way catalyst;Velocity uniform index;Porous medium
为控制汽车有害排放物对大气环境的污染使汽 在分枂时必须将排气歧管不催化器作为一个整体迚行车尾气排放物控制在一个较低的水平来满足排放要 研究排气系统几何模型如图1所示。
1.1 几何模型
该排气系统为紧耦合式即排气歧管直接不催化 1.2多孔介质模型
器相连接为了在催化器前端获得更准确的气流分布 文章中催化剂的参数分别为蜂孔密度为093个/mm2