Soot particle distributions inside a diesel particulate filter during soot loading in plateau environment

Abstract

A three-dimensional diesel particulate filter (DPF) simulation model was developed by using AVL software FIRE to study the effects of four factors on soot particle distributions along the axial and radial directions in the DPF after the model accuracy was validated. An orthogonal test method was used to determine the importance and weights of the design of experiments (DoE) factors such as the expanding angle, the number of channels per square inch, and the exhaust mass flow rate. The effects of these factors on the uniformity of the soot particle distributions were also analyzed. The results show that when the soot loading time was 400 s, the soot particles inside the DPF along the axial direction exhibited a bowl shape, which was high on the both ends and low in the middle. The uniformity of the axial distribution of soot particles reduces significantly with an increase in the number of channels per square inch. The uniformity of the radial distribution reduced with an increase in the expanding angle of the divergent tube. Based on the impacts on the axial uniformity, the three most influencing factors in a descending order are the number of channels per square inch, the exhaust mass flow rate, and the expanding angle of the divergent tube.

摘要

本研究利用AVL FIRE软件建立柴油机微粒捕集器(DPF)三维仿真模型,采用DPF加载试验对模型进行验证。通过单因素仿真揭示4 个关键因素对捕集过程中DPF内部的轴向和径向碳烟沉积量变化和分布特性。研究结果表明: 当加载到400 s 时,轴向碳烟呈现“碗形”分布; 轴向微粒分布的均匀性随着孔目数的增大而显著降低,径向微粒分布的均匀性随着扩张管锥角的增大而明显变小。应用正交试验设计方法研究了DPF 扩张管锥角、孔目数和排气流量三个因素对碳烟加载分布均匀性的影响权重,按照对轴向微粒均匀性的影响程度从大到小依次为孔目数、排气流量和扩张管锥角。