柴油机微粒捕集器灰烬深床沉积压降特性

摘要

Based on the pattern and morphology of deposited ash at the filter wall,a mathematical model of ash deposition in the deep bed was proposed using a physical model of the spherical unit packed bed.The model describes the variation of trap unit size and permeability and investigates the pressure drop on the filter body.Then an accelerated aging bench test was taken to verify the calculation.Results show that pressure drop is increased significantly in the deep bed filtration phase and becomes flat in the cake filtration phase.The deviation between the calculated and experimental values is less than 8％ and this confirms that the model can reasonably describe the ash deposition process at the filter wall.The study has the reference to predict DPF failure and provides theoretical guidance for the optimization of anti-clogging.%基于过滤壁面内灰烬深床沉积规律和形态,运用球状单元填充床多孔介质物理模型,建立了过滤壁面内灰烬深床沉积数学模型.根据该数学模型研究壁面捕集单元尺寸和渗透率随灰烬沉积量和壁面深度的变化规律,以及过滤体压降随深床沉积灰烬质量的变化规律,并通过灰烬沉积加速老化台架试验验证了计算模型.结果表明,灰烬深床沉积阶段过滤体压降明显增加,滤饼沉积阶段压降增加变得平缓,过滤体灰烬深床沉积阶段压降损失计算值与试验值误差不超过8％,该模型能合理描述灰烬在过滤壁面内的沉积过程,为微粒捕集器的抗堵塞优化研究和失效预测提供理论依据.