10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Effect of Soot and Radiation Models in Prediction of Pollutant Formation from Practical Combustion Scenarios
KHALED MOSHARRAF MUKUT, Somesh Roy, Sebastian Ferreyro Fernandez, Daniel Haworth, Michael Modest, Marquette University
Abstract Number: 985 Working Group: Combustion
Abstract Soot or black carbon is one of the major contributors to global climate change, yet there remains a large uncertainty in our understanding of formation and evolution of soot. Anthropogenic combustion is a major source of soot. While combustion research had advanced dramatically over the last couple of decades, formation and growth of soot from real-world combustion scenarios are still poorly understood because of computational complexity and multiphysics interactions involved.
Detailed modeling of combustion requires accurate modeling of flow, chemistry, soot and pollutant formation processes, and thermal radiation. In this work, we focus on soot and radiation modeling in complex combustion configurations. There have been numerous studies on detailed soot modeling in laboratory-scale flames with simple configurations. However, these studies are often restricted to low-sooting conditions. Modeling of thermal radiation is, on the other hand, often simplified either because of numerical complexity or its relatively small importance in small-scale laboratory flames. However, recent studies show that effect of radiation cannot be overlooked in moderate-to-highly sooting flames, high-pressure combustion, and large-scale combustion configurations. To explore the effect of soot and radiation modeling and their interaction we performed detailed simulations of Diesel engine-relevant configurations based on high-pressure Diesel spray experiments reported at Engine Combustion Network (ECN). A semi-empirical and a moment-based detailed soot model with detailed chemical kinetics are used in the coupled simulations of the target cases. A high-fidelity line-by-line photon Monte Carlo and simple gray models have been used for radiation modeling. The primary objective of this work is to explore the effect of model empiricism and interconnection of soot and radiation modeling in practical combustion configurations. Coupled simulations with both detailed and simple soot and radiation models indicate a strong interdependence between soot and radiation models. Significant differences in both size and volume fraction of soot are noted due to the fidelity of the radiation modeling. Apart from the direct connection between predicted soot population and thermal heat loss, the effect of model empiricism on other relevant indicators such as the production of large PAHs and NOx are also quantified.