Spray characteristics of UWS for SCR system in diesel engine
1. School of Automotive and Traffic Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China; 2. Kailong High Technology Co., Ltd., Wuxi, Jiangsu 214153, China
Abstract：Establishing the urea water solution (UWS) spray atomization model for selective catalytic reduction (SCR) aftertreatment system in diesel engine, the physical processes of UWS droplets of turbulence disturbance, distortion, breakup, collisionmerging and wallimpingement bounce in exhaust pipe were investigated comprehensively. The effects of nozzle injection pressure, nozzle injection angle of α, spray cone angle of β, nozzle offset angle of θ and diametertolength ratio of exhaust pipe on the decomposition of UWS droplets were analyzed. The results show that when the injection pressure is too small, the UWS spray tends to be liquid column or large droplets with poor spray atomization ability of UWS, and the NH3 average volume fraction is increased linearly with the increasing of injection pressure. The value of α has significant effect on UWS decomposition, and the NH3 average volume fraction is increased with the increasing of α. The value of β has significant effect on NH3 uniformity coefficient, and the distribution of NH3 tends to be uniform with the increasing of β.With the increasing of θ, the average volume fraction of NH3 is increased, while the uniformity coefficient is decreased sharply. With the increasing of exhaust pipe diameter, the average volume fraction of NH3 is first decreased with latter gradually gentle decreasing.
2019, Vol. 40 
