US Egypt Cooperative Research: Simulation of Diesel Particulate Filters in Exhaust Systems

这一合作研究项目由肯塔基大学列克星敦分校机械工程系的David W.Herrin博士和埃及艾因沙姆斯大学的Tamer M.Elnady博士共同开展，主题是模拟排气系统中的柴油颗粒过滤器。柴油微粒过滤器是一种后处理装置，用于捕获和捕获柴油发动机的烟尘。由于法规越来越严格，欧洲最早将于2013年要求柴油颗粒过滤器，可能还会在美国。虽然它们的主要目的是减少废气污染物，但柴油机微粒过滤器(DPF)也是排气系统中有效的消声装置。对于排气系统的一维声学分析，通常假定只有平面波可以传播，这限制了模拟的频率范围。这一假设适用于小型汽车消声器等应用。然而，与大型柴油发动机消声器(如卡车、重型设备、船舶和发电机组中使用的消声器)的声学波长相比，管道尺寸较大，而更复杂的方法(如有限元或边界元方法)是进行此类分析的基本工具。本项目的目标是改进和验证边界元方法，以预测包括柴油颗粒过滤器在内的排气系统的衰减。虽然DPF本身是一维建模的，但边界元技术允许沿过滤器的上游或下游的三维波动行为。新模型将与艾因沙姆斯大学(Ain Shams University)埃及团队将进行的测量进行验证。将进行参数研究，为DPF装置的布置和选择提供指导。到目前为止，工程师们已经通过昂贵的反复试验的方式，通过试验解决了噪音和废气排放问题。因此，目前的技术浪费了原材料，噪音问题的解决方案不是最优的，而且成本高昂。因此，能够准确预测噪声衰减的经过验证的分析工具将满足迫切的行业需求。此外，所开发的方法应该适用于其他后处理设备，如催化转化器。除了这项研究的潜在环境和工业效益外，这一努力还提供了一个出色的合作机会，特别是因为埃及拥有最先进的消声器测试设施。这个项目的参与者大多是初级科学家和研究生，包括埃及和美国的协调员。这项合作将包括在美国和埃及的短期课程。此外，埃及PI将帮助美国PI开发消声器测试台，而美国合作伙伴将帮助埃及合作伙伴发展他们的计算能力，这表明真正的智力合作。为了充分告知工业界，项目成果将通过由美国PI.协调的可控震源-声学联盟(VAC)向业界传播。该项目由美国-埃及联合基金计划资助，该计划为两国的科学家和工程师进行合作研究提供赠款。

This collaborative research project is being undertaken by Dr. David W. Herrin, Department of Mechanical Engineering, University of Kentucky, Lexington, Kentucky and Dr. Tamer M. Elnady, Ain Shams University in Egypt, on the topic of simulating diesel particulate filters in exhaust systems. A diesel particulate filter is an after-treatment device used to trap and capture soot from diesel engines. Due to increasingly stringent regulations, diesel particulate filters will be required in Europe and possibly the United States as early as 2013. Though their primary purpose is to reduce exhaust pollutants, diesel particulate filters (DPF) are also effective sound attenuation devices in exhaust systems. For one-dimensional acoustic analysis of exhaust systems, it is usually assumed that only plane waves can propagate, which limits the frequency range of the simulation. This assumption is appropriate for applications like small automotive mufflers. However, the duct dimensions are large compared to the acoustic wavelength for large diesel engine silencers like those used in trucks, heavy equipment, ships and generator sets, and more sophisticated approaches like the Finite (FEM) or Boundary Element Methods (BEM) are essential tools for such analyses. The objective of this project is to refine and validate a BEM approach to predict the attenuation from exhaust systems including diesel particulate filters. Though the DPF itself is modeled one-dimensionally, the BEM technique allows for three-dimensional wave behavior up or down stream to the filter. The new model will be validated against measurements to be made by the Egyptian team at Ain Shams University (ASU). A parametric study will be conducted to provide guidance on the placement and selection of DPF units.To date, engineers have addressed problems of noise and exhaust emissions experimentally in a costly trial-and-error fashion. As a result, current technology wastes raw materials, and the solution to the noise problem is sub-optimal and costly. Consequently, a validated analysis tool which accurately predicts noise attenuation will meet a pressing industry need. Furthermore, the developed methodology should be appropriate for other after-treatment devices like catalytic converters. In addition to the potential environmental and industrial benefits of the research, the effort provides an outstanding collaborative opportunity, particularly since Egypt has a state of the art muffler testing facility. Most of the participants in this project are junior scientists and graduate students, including both the Egyptian and US coordinators. The collaboration will include short courses in both the US and Egypt. Additionally, the Egyptian PI will aid the US PI in developing a muffler test rig while the US partner will assist the Egyptian partner in developing their computational capabilities, indicating a true intellectual collaboration. In order to fully inform the industrial community, project results will be disseminated to industry through the Vibro-Acoustics Consortium (VAC) which is coordinated by the US PI.The project is funded under the US-Egypt Joint Fund Program, which provides grants to scientists and engineers in both countries to undertake cooperative research.