对柴油机集成后处理系统催化性能的数值模拟

为研究柴油机集成后处理系统的催化性能，应用CFD软件建立包括尿素水溶液分解、一氧化氮氧化和NOx选择性催化还原化学反应的数值计算模型，计算在SCR催化器上游加装DOC和CDPF催化器后不同排气温度和氨氮比时系统的催化效率。结果表明：当温度达到300℃以上时，尿素分解效率可达81%左右；NO的氧化效率基本维持在45%~60%，系统具有很好的低温催化性能，200℃时NOx催化效率可达76.6%；当氨氮比为1.0时，大多数工况下NOx催化效率均高于90%，最高可达98.7%。通过台架实验验证了模拟结果与实验数据绝对误差在5%以内，表明模拟计算结果可靠，可为后处理系统的设计提供理论指导。

Numerical simulation of catalytic performance of diesel engine integrated after-treatment system

In order to investigate the catalytic performance of diesel engine integrated after-treatment system, the numerical simulation model which including NO oxidation, urea decomposition and SCR reaction were set up and the catalytic performance were studied by using CFD software. The catalytic efficiency of system at different exhaust temperature and NSR calculated after installing DOC and CDPF catalysts on upstream of SCR catalyst. The results show that when the temperature reaches 300℃ above, the decomposition efficiency of urea can reach about 81%; NO oxidation efficiency can reach about 45% to 60%, the system has a good low temperature NOx catalytic efficiency, up to 76.6% at 200℃; when the NSR is 1.0, the NOx catalytic efficiency is higher than 90% at most of the conditions, the highest is up to 98.7%. The absolute error of the calculation and experimental results is less than 5% through the bench test, which shows that the simulation results are reliable and can provide theoretical guidance for the matching optimization of the system.