基于CFD的Urea-SCR混合器性能研究  

Study on Static Mixer Performance in Urea-SCR Systems Based on CFD Code

作　　者：谭理刚[1] 冯鹏飞 杨树宝[2] 郭雅各 李子文 TAN Ligang;FENG Pengfei;YANG Shubao;GUO Yage;LI Ziwen(State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body,Hunan University,Changsha 410082,China;Guangxi Yuchai Machinery Group Co.,Ltd.,Yulin 537000,China)

机构地区：[1]湖南大学汽车车身先进设计制造国家重点实验室,长沙410082 [2]广西玉柴机器股份有限公司,玉林537000

出　　处：《内燃机工程》2018年第4期61-66,共6页Chinese Internal Combustion Engine Engineering

基　　金：国家科技支撑计划(2014BAG09B01)~~

摘　　要：应用计算流体力学(computational fluid dynamics,CFD)软件建立了尿素溶液的喷射雾化和蒸发分解模型,喷雾与壁面相互作用模型和尿素选择性催化还原(SCR)催化器的NOx催化反应模型。研究了叶片型混合器不同布置方案对尿素溶液雾化、蒸发和分解及催化剂入口NH3分布均匀性的影响。数值计算结果显示:叶片型混合器能够提升尿素喷雾雾化效果,提高尿素蒸发分解效率,改善NH3的分布均匀性。混合器布置在离喷嘴1倍排气管直径的位置,SCR系统具有最佳的喷雾雾化效果和尿素分解效率;混合器布置在3倍排气管直径的位置,SCR系统具有最佳的NH3分布均匀性。台架试验和数值计算结果表明:混合器布置在距离喷嘴1倍排气管直径位置时,SCR系统具有更高的NOx的催化转化效率。A numerical model including urea water solution （UWS） spray atomization, urea droplets evaporation and decomposition, spray wall interaction and NOj catalytic reaction in urea based selective catalytic reduction（SCR）systems was established by using computational fluid dynamics（CFD）code. The influence of the different layout schemes of static mixer on the atomization, evaporation, and decomposition of urea solution and the distribution uniformity of NH3 at the entrance of SCR catalytic converter was investigated. The numerical results show that the static mixer can improve the atomization performance of urea spray, the evaporation and decomposition efficiency of urea droplets and the distribution uniformity of NH3. The SCR system achieves the optimum atomization performance and the maximum decomposition efficiency of urea droplets when the static mixer is placed 1D（equal to the diameter of the exhaust pip） away from the injector. While the SCR system has the best distribution uniformity of NH3 when the static mixer is placed 3D away from the injector. The results of the bench test and numerical calculation reveal that the SCR system can achieve a better NOx conversion efficiency when the static mixer is placed 1D away from the injector.

关 键 词：选择性催化还原 混合器 尿素分解效率 分布均匀性 转化效率 

分 类 号：TK422[动力工程及工程热物理—动力机械及工程]