Modeling of Thermophoretic Soot Deposition and Hydrocarbon Condensation in EGR Coolers
Journal
& Paper No.:
SAE-2009-01-1939
Authors:
Mehdi Abarham, John Hoard and Dennis Assanis University of Michigan, W.E. Lay Automotive Laboratory
Dan Styles, Eric W. Curtis and Nitia Ramesh Ford Motor Company
C. Scott Sluder and John M. E. Storey Oak Ridge National Laboratory
Abstract:
EGR coolers are effective to reduce NOx emissions from diesel engines due to lower intake charge temperature.
EGR cooler fouling reduces heat transfer capacity of the
cooler significantly and increases pressure drop across
the cooler. Engine coolant provided at 40-90 C is used to
cool EGR coolers. The presence of a cold surface in the
cooler causes particulate soot deposition and
hydrocarbon condensation. The experimental data also
indicates that the fouling is mainly caused by soot and
hydrocarbons. In this study, a 1-D model is extended to
simulate particulate soot and hydrocarbon deposition on
a concentric tube EGR cooler with a constant wall
temperature. The soot deposition caused by
thermophoresis phenomena is taken into account the
model. Condensation of a wide range of hydrocarbon
molecules are also modeled but the results show
condensation of only heavy molecules at coolant
temperature. Thermal properties of fouled layer are
calculated based on mass fraction of deposited soot and
hydrocarbons. The experiments with the same
conditions ran to validate the model. Hot EGR gases
flow through the inner pipe and the coolant circulates
around it in the outer pipe to keep a constant wall
temperature. Effectiveness, deposited soot mass,
condensed hydrocarbon mass, and pressure drop
across the cooler are the parameters that have been
compared. The results of the model are in a reasonably
good agreement with the experimental results although there are some fields that need to be studied in future to
improve the model.
Paper: Due to the terms of publication, this paper cannot be downloaded at this site. It is available at the SAE Digital Library.