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.
