柴油机Urea-SCR排气管路CFD优化与NO_x排放分析  

CFD Optimization and NO_x Emission Analysis of Diesel Urea-SCR Exhaust Pipe System

作　　者：王谦[1] 刘倩[1] 罗晶[1] 何志霞[1] 刘庆[1] 徐飞[1] 

机构地区：[1]江苏大学能源与动力工程学院,江苏镇江212013

出　　处：《内燃机学报》2009年第6期523-528,共6页Transactions of Csice

基　　金：国家自然科学基金项目(50576032;50806030)

摘　　要：对Urea-SCR(尿素-选择性催化还原技术)排气管路中尿素水溶液蒸发雾化过程进行了计算流体动力学(CFD)模拟。在试验验证喷雾模型的基础上,对排气管路中尿素喷射、雾化及浓度(质量分数)分布进行模拟计算,同时对尿素结晶成因进行了分析,并提出减少结晶形成的方法。通过优化排气管路布置方案包括喷嘴位置、喷雾锥角和管路尺寸等参数,从而改善尿素在尾气中浓度分布的均匀性,提高催化剂转换效率。通过试验测试,采用优化后的排气管道布置方案,SCR系统的转换效率最大可以达到66%,NO_x排放可以达到国Ⅳ水平。With the aid of CFD （ Computational Fluid Dynamic）, a three-dimension modeling was made to simulate spray and evaporation process of urea solution in the different exhaust pipe layout. Optimization of the layout based on the validation of spray injection model was made to avoid urea crystallization, and SCR catalyst conversation was increased with uniform distribution of urea droplet in the exhaust. The test results showed that the maximum NOx conversion efficiency of SCR system with optimized layout can get 66%, meeting China IV emission standards.

关 键 词：柴油机 SCR NOX排放 优化 

分 类 号：TK402[动力工程及工程热物理—动力机械及工程]