立体选择性催化还原(SSCR)系统NH_3与尾气混合特性的仿真研究

Simulation Study for Mixing Characteristics of NH_3 and Automobile Exhaust in the SSCR System

利用AVL FIRE三维商用仿真软件对立体选择性催化还原(solid selective catalytic reduction,SSCR)系统直接喷射NH3时,NH3与尾气在排气道的影响因素进行模拟计算,考察的因素包括工况、NH3温度、喷嘴的安装角度以及喷嘴位置。结论如下:NH3与尾气混合受来流影响较大,排气流量大,排气温度高时,利于NH3与尾气混合;NH3初始温度对于气体混合影响不大;喷嘴安装角度增大利于气体轴向分布,也利于气体混合;SSCR系统直接喷射NH3可以优化喷嘴位置,使排气系统体积减少。

The influence factors to the NH3 spray of Solid Selective Catalytic Reduction （SSCR） system was researched by using AVL FIRE 3D commercial simulation software when NH3 and exhaust gas mix in exhaust passage. The influence factors include engine condition, NH3 temperature , nozzle installation angle and nozzle position. The conclusions are as follows：engine condition has much Influence for NH3 and automobile exhaust mixing, the mixing is better, the exhaust flow is larger, the exhaust temperature is high;NH3 initial temperature for the gas mixing has little influence ; nozzle angle increases is good for the axial distribution of gas and the gas mixing characteristics; For the SSCR system direct injecting NH3 can optimize the nozzle position, and reduce the exhaust system volume.