柴油机壁流式过滤体非稳态捕集过程的计算模型

A Computational Model of Diesel Wall-Flow Filter for Unsteady-State Filtration Process

基于排气在柴油机壁流式过滤体内的流动特点,并在综合分析壁流式过滤体深床捕集阶段捕集特点和滤饼捕集阶段捕集特点的基础上,建立了壁流式过滤体非稳态捕集过程的计算模型。该模型通过提出容纳度的概念,有效地区分了深床捕集阶段和滤饼捕集阶段;通过提出微粒在过滤壁表面沉积效率的概念,定量地描述了沉积在过滤壁表面的微粒量。基于该模型,介绍了计算算法,并编制了相应的计算程序。使用该模型研究了过滤体的捕集效率、流动阻力以及沉积在过滤体内微粒质量的非稳态变化规律。计算结果与试验结果吻合得较好,表明该模型在工程实际应用中具有可行性。

Based on the air-flow characteristics of diesel wall-flow filter, a computation model of wall-flow filter for unsteady filtration process was proposed by comprehensively analyzing the characteristics of the deep-bed filtration and the cake filtration. This model can distinguish between the deep-bed filtration and the cake filtration by introducing the concept of carrying capacity, and can describe the particle amount deposited on the surface of filter wall by introducing the concept of depositing efficiency. Based on this consideration, a computational method is described along with code programming. The unsteady-state behaviors of filtration efficiency, flow resistance and the particle deposition amount in the filter were studied using this model. The calculated results show good agreement with the experimental data, indicating the feasibility of the model in engineering application.