【摘要】 为了改善柴油机低排温（200℃）下尿素雾化效果不好的问题，本文研究了柴油机低排温条件下混合器本体温度对SCR系统的影响。基于云内4102柴油机，在1 200 r·min^-1、20%负荷条件下，运用计算流体动力学（CFD）技术进行数值模拟。通过对比2种混合器的压降、迹线、混合器上壁面液膜分布情况，选取更适合的混合器类型。通过改变混合器的本体温度，来对比分析不同温度的混合器对壁面液膜和催化器前端NH₃均匀性系数的影响。研究结果表明：混合器本体温度的变化对于液膜的形成影响较大，混合器本体温度从100℃升高到200℃时，混合器上液膜区域明显减少。混合器本体温度的升高对NH₃均匀性系数有显著影响。随着混合器本体温度升高，NH₃均匀性系数明显升高，且随着温度的不断升高，NH₃均匀性系数越来越接近1。使混合器保持合适的温度，能够有效提高尿素的雾化效果和NH₃均匀性系数。更多还原

【Abstract】 In order to improve the poor urea atomization effect of diesel engine at low exhaust temperature（ 200 ℃）,this paper studied the effect of mixer body temperature on SCR system under low exhaust temperature condition of diesel engine. Based on 1 200 r·min^-1,20% load condition of 4102 diesel engine in the cloud,computational fluid dynamics（ CFD） technology was used for numerical simulation. Comparing with the pressure drop,trace and liquid film distribution on the upper wall of the two mixers,the more suitable mixer type was selected. By changing the temperature of the mixer,the effect of different temperature of the mixer on the wall liquid film and the NH₃ uniformity coefficient in front of the catalytic converter was compared and analyzed. The results show that the temperature change of the mixer body has a great influence on the formation of liquid film. When the temperature of the mixer increases from 100℃ to 200 ℃,the liquid film area on the mixer decreases obviously. The increase of the body temperature of the mixer has a significant effect on the NH₃ uniformity coefficient. As the temperature of the mixer body increases,the uniformity coefficient of NH₃ increases obviously,and the uniformity coefficient of NH₃ is closer and closer to 1 with the increasing temperature. The atomization effect of urea and the uniformity coefficient of NH₃ can be effectively improved by keeping the mixer at a proper temperature.更多还原