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Modeling and simulation of wall-flow diesel particulate filter during loading and regeneration.

机译：装填和再生过程中壁流柴油机颗粒过滤器的建模和仿真。

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摘要

The advent of tightened diesel emission regulations has led to the development and implementation of various diesel in-cylinder controls and after-treatment devices. As the most promising after-treatment device in reducing particulate emission from diesel engines, the diesel particulate filter (DPF) was developed in the 1980s and has undergone notable improvements. The objective of this dissertation is to explore complicated physical processes in the DPF during loading and regeneration.; In the 1-D model, quasi-steady state conservations of mass and momentum are solved by a shooting method coupled with a Runge-Kutta method. A filtration model based on unit collector filtration theory is used to determine transient filtration behaviors of the porous wall. Transient conservations of energy are solved with fully implicit finite difference method to find the temperature field.; The major challenge with DPF is the uncertainty of the regeneration process. The exothermic soot oxidation during regeneration leads to sharp rise in local temperature and temperature gradient, which makes the DPF susceptible to melting and cracking. As an extension of the 1-D model, a quasi 3-D model is developed to locate hot spots in the DPF. The 3-D Navier-Stokes equations are solved using order of magnitude analysis and integral method. The 3-D transient conservation of energy is solved by a modified Alternative-Direction-Implicit (ADI) method to find the temperature distribution, which enables further numerical simulation of thermal stress.; A displacement-based finite element method is employed to solve for the 3-D thermal stress induced by high temperature and temperature gradient during DPF regeneration. This finite element model is self-contained and independent of any commercial package. It includes functions of meshing body, assembling global stiffness matrix and force vector, solving final equilibrium equations and post-processing.; Finally, parametric studies are carried out with these three models to investigate the impact of DPF geometric designs on performance. Primary attention is paid to pressure drop, peak temperature and thermal stress, which are associated with diesel thermal efficiency and potential DPF failure due to melting and cracking.
机译：越来越严格的柴油排放法规的出现导致了各种柴油缸内控制和后处理装置的开发和实施。作为减少柴油机微粒排放的最有希望的后处理设备，柴油微粒滤清器（DPF）于1980年代开发，并进行了显着改进。本文的目的是探讨DPF在加载和再生过程中的复杂物理过程。在一维模型中，质量和动量的准稳态守恒通过与Runge-Kutta方法结合的射击方法解决。基于单元收集器过滤理论的过滤模型用于确定多孔壁的瞬时过滤行为。用完全隐式有限差分法求解能量的瞬时守恒，以找到温度场。 DPF的主要挑战是再生过程的不确定性。再生过程中放热的烟灰氧化导致局部温度和温度梯度急剧上升，这使DPF易于熔化和破裂。作为1-D模型的扩展，开发了一种准3-D模型来定位DPF中的热点。使用量级分析和积分方法求解3-D Navier-Stokes方程。改进的交替方向隐式（ADI）方法解决了温度的3-D瞬态守恒问题，以找到温度分布，从而可以进一步对热应力进行数值模拟。基于位移的有限元方法用于解决DPF再生过程中高温和温度梯度引起的3-D热应力。该有限元模型是独立的，并且独立于任何商业软件包。它包括啮合体，组装整体刚度矩阵和力矢量，求解最终平衡方程和后处理的功能。最后，使用这三个模型进行参数研究，以研究DPF几何设计对性能的影响。主要关注压降，峰值温度和热应力，这些压降与柴油的热效率和由于熔化和破裂而引起的潜在DPF失效有关。

著录项

  • 作者

    Guo, Zhenhua.;

  • 作者单位

    The University of Nebraska - Lincoln.;

  • 授予单位 The University of Nebraska - Lincoln.;
  • 学科 Engineering Mechanical.
  • 学位 Ph.D.
  • 年度 2006
  • 页码 126 p.
  • 总页数 126
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 机械、仪表工业;
  • 关键词

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