低温条件Urea-SCR喷射系统结构对雾化混合特性的影响研究  

Influence of Structure of Urea-SCR Injection System on Spray and Mixing Characteristics at Low Exhaust Temperature

作　　者：文帅[1] 贾和坤[1] 李西锋 WEN Shuai;JIA He-kun;LI Xi-feng(School of Automotive and Traffic Engineering,Jiangsu University,Jiangsu Zhenjiang 212013,China)

机构地区：[1]江苏大学汽车与交通工程学院,江苏镇江212013

出　　处：《机械设计与制造》2018年第A02期96-99,共4页Machinery Design & Manufacture

基　　金：江苏省自然科学基金(BK20150520);江苏省科技成果转化专项资金项目(BA2016096)

摘　　要：采用数值模拟方法,对低排温条件下柴油机Urea-SCR系统尿素水溶液(UWS)喷雾雾化和混合过程进行了研究,分析了喷射压力、喷射角度对排气管内液滴蒸发和分布以及NH3浓度均匀性的影响,并利用喷雾激光测试手段,对发动机运行条件下透明石英排气管内液滴分布进行了测量。结果表明:提升喷射压力同时适当减小喷射角度,能够降低喷雾液滴大小,促进液滴蒸发,改善管内液滴分布进而提升氨浓度分布均匀性;20bar喷射压力和30°喷射角度方案由于其较好的喷雾特性和较少的喷雾撞壁现象,使得催化剂前端面NH3浓度分布更为均匀,有利于提升SCR系统转化效率。The spray atomization and mixing process of urea water solution(UWS)for diesel engines Urea-SCR were inves-tigated at low exhaust temperature by numerical simulation.The influence of injection pressure,injection angle on evaporation and distribution of droplets in the exhaust pipe and the uniformity of NH3 concentration were analyzed.The droplets distribution in a transparent quartz glass tube was measured through laser test.The results show that increasing injection pressure and decreasing injection angle properly can reduce the droplet size,promote droplet evaporation,improve the droplet distribution and thus the uniformity of NH3 concentration distribution;the distribution of NH3 concentration in the front surface of the catalyst is more uniform with the injection pressure 20bar and angle 30°due to the better spray characteristics and few spray impingement,which is conducive to improve the conversion efficiency of SCR system.

关 键 词：内燃机 柴油机 选择性催化还原 喷雾 均匀性 

分 类 号：TH16[机械工程—机械制造及自动化] TK421.5[动力工程及工程热物理—动力机械及工程]