紧凑型DOC-混合器-SCR后处理系统数值模拟

为提高SCR系统的转化效率,提出紧凑型DOC-混合器-SCR后处理系统,建立了3种不同结构的后处理模型。采用计算流体力学(CFD)结合化学反应动力学的方法,建立了柴油机SCR-NOx催化器三维数值模型,该模型包含尿素水溶液喷射、液滴蒸发和热解、NOx催化还原化学反应整个尾气后处理过程,得到了紧凑型后处理系统的湍流动能场、速度流场、浓度场的分布规律,并与传统型后处理系统模拟仿真结果进行对比。研究结果对柴油机后处理系统设计具有参考价值。

Numerical Simulation on Compact DOC-Mixer-SCR Aftertreatment System

In order to improve the conversion efficiency of SCR system ,a compact DOC-mixer-SCR aftertreatment system was put forward and three kinds of aftertreatment models were built .With the aid of computational fluid dynamic (CFD) coupled with chemical reaction dynamics ,a 3D model of SCR-NOx catalytic converter was established .With the model ,the whole after-treatment process including the injection of urea aqueous solution ,the evaporation and thermal decomposition of droplet and NOx catalytic reaction was simulated and the distribution law of turbulent kinetic energy field ,velocity field and concentration field was acquired .In addition ,the simulated results were compared with those of traditional aftertreatment system .The re-search results provide the reference for the design of aftertreatment system .