柴油机Urea-SCR催化器优化设计及仿真研究  

Optimization Design and Simulation Study of Diesel Engine Urea-SCR Catalyst

作　　者：张礼斌 刘帅[1] 李艳 ZHANG Libin;LIU Shuai;LI Yan(School of Automotive and Traffic Engineering,Jiangsu University,Zhenjiang 212013,China;Danfoss Power System(Jiangsu)Co.,Ltd.,Zhenjiang 212000,China)

机构地区：[1]江苏大学汽车与交通工程学院,江苏镇江212013 [2]丹佛斯动力系统(江苏)有限公司,江苏镇江212000

出　　处：《现代车用动力》2019年第1期34-40,共7页Modern Vehicle Power

基　　金：江苏高等学校自然科学基金(18KJB470006)

摘　　要：运用计算流体力学(CFD)软件,对结构改进前后的选择性催化还原(SCR)催化器内流场进行了三维稳态流动数值模拟,对比分析了改进前后4种不同结构的催化器内流动特性,研究得到不同结构下压力、温度、流速和NO的质量分数之间的关系。结果表明:优化设计后的SCR催化器增大了载体中部高速区的占比,使载体内流速相对均匀。降低了由于温度、压力产生的涡流,提高了尿素液滴与尾气的混合均匀性和尾气中NO_x的转化率。当SCR催化器长度为180 mm,宽度为160 mm,角度为36.5°时,管内压力、温度、流速达到最佳状态且NO_x的转化效率达到最高。模拟结果为进一步优化设计柴油机SCR催化器提供了设计依据。This paper launches the three dimensional steady numerical simulation of flows about the flow field inside the SCR catalysts before and after its structural improvement through computational fluid dynamics(CFD) software, and makes comparative analysis of flow characteristics in catalysts with four different structures before and after its improvement, then the relationship among pressure, temperature, flow velocity and NO mass fraction can be obtained. The results show that the optimized SCR catalyst increases the proportion of high-speed zone in the middle of the carrier and makes the flow velocity in the carrier relatively well-distributed. Besides, the vortex generated by temperature and pressure is reduced, and the mixing uniformity of urea droplets and exhaust and the conversion rate of NO_x in the exhaust are improved. When the SCR catalyst is 180 mm in length, 160 mm in width and 36.5 in angle, the pressure, temperature and flow velocity in the pipe can reach the optimal state and the NO_x conversion efficiency reaches the highest. The simulation results provide a design basis for further optimizing design of SCR catalyst for diesel engines.

关 键 词：柴油机 氮氧化物 SCR催化器 结构设计 仿真 

分 类 号：TK421.5[动力工程及工程热物理—动力机械及工程]