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

这项合作研究项目由大卫W博士承担。Herrin，肯塔基州列克星敦大学机械工程系，肯塔基州和Tamer M. Elnady，埃及艾因夏姆斯大学，关于模拟排气系统中的柴油颗粒过滤器的主题。 柴油颗粒过滤器是一种后处理装置，用于捕获柴油发动机的烟灰。由于越来越严格的法规，柴油颗粒过滤器将需要在欧洲和美国可能早在2013年。虽然柴油机微粒过滤器（DPF）的主要目的是减少排气污染物，但它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，通常假设只有平面波可以传播，这限制了模拟的频率范围。这种假设适用于小型汽车消声器等应用。然而，与卡车、重型设备、船舶和发电机组中使用的大型柴油发动机消声器的声波波长相比，管道尺寸较大，并且更复杂的方法如有限元（FEM）或边界元法（BEM）是此类分析的必要工具。本项目的目的是完善和验证边界元法的方法来预测从排气系统，包括柴油机微粒过滤器的衰减。虽然DPF本身是一维建模的，但BEM技术允许过滤器上游或下游的三维波行为。新模型将根据艾因夏姆斯大学（ASU）埃及团队的测量结果进行验证。将进行参数研究，为DPF装置的放置和选择提供指导。迄今为止，工程师们已经以昂贵的试错方式通过实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，并且噪音问题的解决方案是次优的且昂贵的。因此，一个经过验证的分析工具，准确地预测噪声衰减将满足迫切的行业需求。此外，所开发的方法应适用于其他后处理装置，如催化转化器。除了这项研究潜在的环境和工业效益外，这项工作还提供了一个绝佳的合作机会，特别是因为埃及拥有最先进的消声器测试设施。该项目的大多数参与者是初级科学家和研究生，包括埃及和美国的协调员。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开发消声器试验台，而美国合作伙伴将帮助埃及合作伙伴开发其计算能力，这表明了真正的智力合作。为了充分告知工业界，项目结果将通过美国PI协调的振动声学联盟（VAC）向工业界传播。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提供赠款，以进行合作研究。

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.