基于氨均匀性对SCR系统性能影响的多通道一维仿真模型构建
田文龙，罗峰，郎俊宇，马跃晋，李国祥*
山东大学核科学与能源动力学院，山东 济南 250061
摘要：为提高全球统一稳态循环（world harmonized steady-state cycle，WHSC）工况中仿真计算的柴油机NOx排放的准确性，分析造成仿真计算和试验测量的柴油机排放中NOx差距过大的原因；提出一种多通道一维仿真模型，分析选择性催化还原（selective catalytic reduction，SCR）系统中氨均匀性对NOx排放的影响。结果表明：传统的一维仿真方法没有考虑氨均匀性对SCR性能的影响是造成仿真计算和试验测量的柴油机NOx排放差距过大的原因；提出的多通道模型可以很好地预测氨均匀性对SCR性能的影响，当氨均匀性为0.95时，仿真计算的NOx排放与试验的误差较小。考虑氨均匀性受工况变动的影响，提出的分段式氨均匀性方法可以进一步降低NOx排放预测误差，将误差控制在2%以内。
关键词：尿素-SCR系统；建模；多通道；氨均匀性
Construction of a multi-channel 1-D simulation model based on the effect of ammonia uniformity on SCR system performance
TIAN Wenlong, LUO Feng, LANG Junyu, MA Yuejin, LI Guoxiang*
School of Nuclear Science, Energy and Power Engineering, Shandong University, Jinan 250061, China
Abstract: To enhance the accuracy of NOx emission simulation for diesel engines under the world harmonized steady-state cycle (WHSC), the causes of the significant discrepancy between simulated and experimentally measured NOx emissions in diesel engine exhaust are analyzed. On this basis, a multi-channel one-dimensional simulation model is proposed to investigate the influence of ammonia uniformity on NOx emissions in the selective catalytic reduction (SCR) system. The results demonstrate that the traditional one-dimensional simulation method, which neglects the impact of ammonia uniformity on SCR performance, is the primary reason for the large deviation between simulated and experimentally measured NOx emissions. The multi-channel model proposed in this study effectively predicts the effect of ammonia uniformity on SCR performance. When the ammonia uniformity index reaches 0.95, the error between the simulated NOx emissions and experimental result is significantly reduced. Considering the influence of operating conditions on ammonia uniformity, a segmented ammonia uniformity model is introduced. This approach further reduces the prediction error of NOx emissions, maintaining the error within 2%.
Keywords: urea-SCR system; modelling; multi-channel; ammonia uniformity
