Research

Project Number:
01-2

Research Project:
Reducing Pollutants From Mobile Sources

P.I. Name & Address:
Hamid Rahai
Mechanical Engineering Department
California State University, Long Beach
Long Beach, CA 90840
Tel: (562) 985-5132
Fax: (562) 985-4408
Email: rahai@csulb.edu

Project Objective:
Mobile sources such as trucks and buses emit significant amounts of pollutants into the atmosphere. In most metropolitan areas these pollutants are locally concentrated with gradual dispersion and mixing with the atmosphere. High concentrations of these pollutants are health hazard and provide a challenge for air quality management.

Catalytic exhaust devices have been used to reduce tailpipe emissions. For the diesel engines, a recent study have found that, low-sulfur diesel, combined with catalytic exhaust control technology can reduce the emissions significantly.

Further reduction in exhaust pollutions can be obtained by secondary treatment of these gases, provided that the process does not impose additional blockage or pressure drop and can effectively oxidize the remaining pollutants. The proposed study will focus on development of a specific coil, coated with an oxidizer for secondary treatment of the exhaust gases. The optimized coil will be placed inside the exhaust pipe after the catalytic converter where the temperature of the gases is high and further treatment is possible. Previous investigations by Rahai et al (2000), Rahai and Wong (1998) and Rahai and Hoang (1999) on mixing enhancement using coil inserts, have shown that increased mixing of up to 25% can be obtained with coil inserts of specific configuration. The rate of mixing enhancement can be a parameter for assessing the effectiveness of the oxidation process and thus with the proposed approach a significant decrease in the remaining exhaust gas pollutants is expected.

The first part of the investigation will focus on optimizing the coil configuration for the highest possible mixing enhancement. The second part of the investigation will use an oxidizer coil with the optimized configuration developed from part one of the investigation for secondary treatment of the exhaust gases. The final developed oxidizer coil has strong commercial potential.

Task Descriptions:
1.Investigation of the effect of the Coil Length on the Mixing Enhancement ofthe Jet (2 months).
2.Investigation of Dispersion and Mixing of a Passive Scalar from a Round RibbedTube (4 months)
3.Investigation of the Pressure Drop for the Optimized Coil. (2 months)
4. Investigation of the Effect of an Oxidizer Coil on Exhaust Emissions (4 months)

Milestones, Dates:
Final Draft Report by 5/31/02

Total Budget:
$50,000

Student Involvement:
Two Research Assistants @ 50% time for 12 months

Relationship to Other Research Projects:
Related to 99-5, spans goods movement and transit focus areas

Technology Transfer Activities:
Project report will be posted on website; Project is aimed at eventual commercialization

Potential Benefits of the Project:
Reduce emissions from heavy duty diesel vehicles

TRB Keywords:
Emissions, engines

Primary Subject:
Vehicle fuels and energy sources, including production and delivery system

Goals:
Human and Natural environment

Enabling Research:
Energy and environment

Modal Orientation:
Transit, Highway