柴油机SCR催化器NOx转化效率影响因素的数值分析

doi:10.16180/j.cnki.issn1007-7820.2022.06.0014

摘要/Abstract

摘要：

为探究旋流混合器温度以及尿素注入流量对NO_x转化效率的影响,以某柴油发动机SCR催化器为研究对象,运用CFD技术对其进行化学反应和稳态流动数值模拟。通过改变旋流混合器的温度和尿素注入流量,对比分析不同情况下NH₃的浓度与均匀性系数以及出口处NO_x的质量分数。研究结果表明,SCR催化器出口处NO_x质量分数分布呈现中心低边缘高的规律,旋流混合器温度的变化对NH₃速度均匀性系数影响较小。在其温度为400 ℃时NH₃分布较均匀,NH₃生成率和NO_x转化效率较高。结果表明,选择合适的尿素注入流量,能够提高NO_x转化效率和尿素利用率。

关键词: 柴油机, SCR, CFD, 选择性催化还原, 数值模拟, 均匀性系数, NO_x转化效率, 尿素利用率

Abstract:

In order to explore the influence of the temperature of cyclone mixer and urea injection flow rate on NO_x conversion efficiency, CFD technology is used to study the SCR catalytic converter for a diesel engine by chemical reaction and steady flow numerical simulation. By changing the temperature of the cyclone mixer and the urea injection flow rate, the concentration and uniformity coefficient of NH₃ and the mass fraction of NO_x at the outlet are compared under different conditions. The results show that the mass fraction distribution of NO_x at the outlet of SCR catalyst presents the law of low center and high edge, and the temperature change of cyclone mixer has little effect on the uniformity coefficient of NH₃velocity. When the temperature is 400 ℃, the NH₃ distribution is more uniform, the NH₃ generation rate and NO_x conversion efficiency are higher. These results indicate that the NO_x conversion efficiency and urea utilization rate can be improved by selecting the appropriate urea injection flow rate.

Key words: diesel engine, SCR, CFD, selective catalytic reduction, numerical modeling, uniformity coefficient, NO_x conversion efficiency, utilization rate of urea

中图分类号:

TP31

赵浩,何伟. 柴油机SCR催化器NO_x转化效率影响因素的数值分析[J]. 电子科技, 2022, 35(6): 89-94.

ZHAO Hao,HE Wei. Numerical Analysis of NO_x Conversion Efficiency of SCR Catalytic Converter of Diesel Engine[J]. Electronic Science and Technology, 2022, 35(6): 89-94.

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