国六柴油机双旋流SCR混合器试验研究

张晓丽; 王霞; 荣超; 石代龙; 安邦; 王东升; 杨永春

车用发动机 ›› 2021, Vol. 0 ›› Issue (2) : 49-55.

栏目

国六柴油机双旋流SCR混合器试验研究

张晓丽，王霞，荣超，石代龙，安邦，王东升，杨永春

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Experimental Study of Twintwist flow SCR Mixer for China Ⅵ Diesel Engine

ZHANG Xiaoli,WANG Xia,RONG Chao,SHI Dailong,AN Bang,WANG Dongsheng,YANG Yongchun

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摘要

为解决国Ⅵ柴油机SCR后处理系统在低排温、低负荷工况下存在的尿素结晶问题，采用CFD和试验研究相结合的方法，对某重型国Ⅵ柴油机后处理SCR单旋流混合器进行结构优化，设计出了一种双旋流混合器。对双旋流混合器进行NO_x单点转化效率试验、瞬态WHTC排放试验以及10 h发动机台架尿素结晶验证试验。模拟结果表明：双旋流混合器能够产生更强的旋流效果，促使尿素喷雾和尾气充分混合、蒸发分解，且使氨分布均匀性指数提高了15.19%。试验结果表明：相较于单旋流混合器，双旋流混合器在氨氮比为0.7，0.9和1.2时的NO_x转化率分别提高1.58%，1.78%和0.38%，NO_x排放显著降低，混合器壁面未出现尿素结晶，解决了低温、低负荷工况下的尿素结晶问题。

Abstract

For the urea crystallization problems of SCR at low exhaust temperature and low load, the combination of CFD and experiment were used to optimize a singleswirl SCR mixer of a heavyduty China Ⅵ diesel engine, and a twintwist flow SCR mixer was designed. Then singlepoint NO_x conversion efficiency test, WHTC and 10 h verification test for urea crystallization were conducted on the test bench. The simulation results show that the twintwist flow SCR mixer can promote the mixing between urea solution and exhaust gas so as to evaporate and decompose quickly and leads to the increase of the distribution uniformity of NH₃ concentration by 15.19%. The test results show that the twintwist flow SCR mixer can increase NO_x conversion rate by 1.58, 1.78% and 0.38% respectively corresponding to ANR of 0.7, 0.9 and 1.2 and the NO_x emission obviously reduces. The crystallization does not occur on the wall of SCR mixer and the problem is hence solved.

导出引用

张晓丽，王霞，荣超，石代龙，安邦，王东升，杨永春. 国六柴油机双旋流SCR混合器试验研究[J]. 车用发动机. 2021, 0(2): 49-55

ZHANG Xiaoli,WANG Xia,RONG Chao,SHI Dailong,AN Bang,WANG Dongsheng,YANG Yongchun. Experimental Study of Twintwist flow SCR Mixer for China Ⅵ Diesel Engine[J]. Vehicle Engine. 2021, 0(2): 49-55