柴油机壁流式过滤体捕集与流阻性能影响规律

Characteristics of Filtration and Flow-resistance of Wall-flow Diesel Particulate Filter

根据气流在柴油机壁流式微粒捕集器内的流动特点,将过滤壁面假设为由若干球状单元组成,建立了壁流式过滤体捕集过程的数学模型。研究了排气特征、过滤体结构参数对壁流式过滤体捕集及流阻性能的影响规律。结果表明,减小排气流量、增大过滤体体积等方法,既能优化捕集性能,又能优化流阻性能;减小过滤体长径比,能优化流阻性能,而对捕集性能没有影响;增大过滤壁厚度,能优化捕集性能,但会使流动性能恶化;改变排气温度和孔道宽度,对捕集性能及流阻性能的影响都较小。最后通过试验验证了数学模型的准确性。

Based on the air-flow characteristics of diesel wall-flow particulate filter, the mathematical model of loading process for the wall-flow filter was proposed. In this model, the porous wall was assumed to be composed of numerous spherical collectors. The effects of the exhaust-flow characteristic and the structural parameter of filter on the over-all properties of filter were analyzed. The results showed that decreasing exhaust-flow and increasing volume of filter optimize the characteristics of filtration and flow-resistance. Decrease in the ratio of length to diameter of filter optimize flow-resistance, whereas has no influence on filtration. Increment in wall thickness optimizes filtration, whereas deteriorates flow-resistance. Exhaust temperature and channel width both have a minor influence on both filtration and flow-resistance. The experimental results verified the accuracy of mathematical model.