The Deconvolution of the Thermal, Dilution, and Chemical Effects of Exhaust Gas Recirculation (EGR) on the Reactivity of Engine and Flame Soot


In a recent paper, we demonstrated that the exhaust gas recirculation (EGR) enhanced the oxidative reactivity of diesel engine soot. In this paper, we show that simulated EGR, via carbon dioxide (CO2) addition to the intake air to an engine at concentrations of 0, 2, 4, and 8 vol.% and to the oxidizer stream of an ethylene diffusion flame at concentrations of 0, 5, and 10 vol.%, affects the reactivity of the soot in the same manner as actual EGR. Motivated by this fact, post-flame ethylene soot was produced from a co-flow laminar diffusion flame to better understand the mechanism by which the CO2 affects soot reactivity. This objective was accomplished by successfully isolating and examining the thermal, dilution, and chemical effects of the CO2 on soot reactivity. These three effects account for 45%, 35%, and 20% of the total reactivity of soot respectively, with the thermal effect being the most important factor governing the soot reactivity. The results showed that all of these effects account for a measurable increase in soot reactivity.


Chemical and Biochemical Engineering


United States. Department of Energy
National Science Foundation (U.S.)
Saudi Ministry of Higher Education


The authors wish to thank the Department of Energy for support under Grant # DE-FC26-03NT41828, the National Science Foundation for support under Grant # CTS-0553339 and the Saudi Ministry of Higher Education for fellowship support for Dr. Al-Qurashi.

Keywords and Phrases

Chemical effect; Co-flow; Diesel particulate; Ethylene diffusion flames; Flame soot; Intake air; Laminar diffusion flames; Oxidative reactivity; Oxidizer stream; Soot oxidation; Air intakes; Carbon dioxide; Diesel engines; Dust; Ethylene; Soot; Exhaust gas recirculation; Carbon dioxide; Ethylene; Article; Chemical reaction; Combustion; Diesel engine; Diffusion; Dilution; Exhaust gas; Exhaust gas recirculation; Laminar flow; Oxidation; Priority journal; Soot; Thermal diffusion; Thermogravimetry; Exhaust gas recirculation; Nanostructure; Reactivity

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Article - Journal

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© 2011 Elsevier, All rights reserved.

Publication Date

01 Sep 2011