Numerical Investigation of NO2 Formation Mechanism in H2-Diesel Dual-Fuel Engine Carnegie Mellon Univ

Format:

Conference/Event

Author/Creator:

Singh, Singh, author.

Contributor:

Li, Hailin

Liu, Shiyu

Conference Name:

SAE 2012 World Congress & Exhibition (2012-04-24 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2012

Summary:

The nitrogen dioxide (NO₂) emissions of compression ignitiondiesel engines are usually relatively small, especially whenoperated at medium and high loads. Recent experimentalinvestigations have suggested that adding hydrogen (H₂) into theintake air of a diesel engine leads to a substantial increase inNO₂ emissions. The increase in NO₂ fraction in the totalNOx is more pronounced at lower engine load than atmedium- and high-load operation, especially when a small amount ofH₂ is added. However, the chemistry causing the increased NO₂formation in H₂-diesel dual-fuel engines has not been fullyexplored.In the present work, kinetics of NO and NO₂ formation in aH₂-diesel dual-fuel engine are investigated using a CFD modelintegrated with a reduced hydrocarbon oxidation chemistry and anoxides of nitrogen (NOx) formation mechanism. A low-loadand a medium-load operating condition are selected for numericalsimulations. The experimental trends of NOx emissionsare reproduced with the numerical model. The effect of in-cylinderchemical and thermal conditions on the formation of nitric oxide(NO) and NO₂ is studied through a set of numerical simulations. Itis found that the evolution of in-cylinder HO₂ radicals andin-cylinder mixture temperature are both responsible for theobserved trends in NO₂ emissions. The presence of increased levelsof HO₂ and reduced temperature of the combustion products provide afavorable environment for conversion of NO to NO₂. Although the HO₂radicals necessary for this conversion are produced mainly duringthe mixing controlled diffusion combustion of H₂ and diesel, theconversion of NO to NO₂ is mainly observed after the completion ofthe main combustion process

Notes:

Vendor supplied data

Publisher Number:

2012-01-0655

Access Restriction:

Restricted for use by site license