车用催化转化器内气体的流动均匀性

使发动机的废气尽可能均匀地通过整个催化剂载体是催化转化器优化设计的主要目标之一。采用数值模拟的方法研究了车用催化转化器内气体的流动均匀性 ,把蜂窝载体当作连续的多孔介质进行处理 ,用当量连续法建立了载体的流体动力学模型 ,并用计算流体力学软件 STAR- CD对常见的圆形催化转化器进行稳态流动数值模拟 ,模拟结果与试验结果吻合良好。在此基础上 ,研究了催化转化器结构、空速以及载体阻力等对流动的影响。研究表明 :对扩张管的形状、结构进行优化设计是改善催化转化器内气体流动均匀性的一种切实可行的办法

Gas flow uniformity in automotive catalytic converters

The uniform flow of engine exhaust gas through substrates is one of the main objects in the optimization of catalytic converters. This paper numerically simulated the flow uniformity of automotive catalytic converters. The honeycomb substrate was modeled as a porous medium by using an equivalent continuum approach. The steady state air flow in a cylindrical automotive catalytic converter was simulated with the CFD code STAR CD. The effects of the diffusers, the space velocity and the substrate resistance on the flow uniformity were investigated. The simulation results show that the flow uniformity can be effectively improved by optimizing the structure and configuration of the catalytic converter.