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Date of Award

2016

Document Type

Campus Access Master's Report

Degree Name

Master of Science in Mechanical Engineering (MS)

Administrative Home Department

Department of Mechanical Engineering-Engineering Mechanics

Advisor 1

Jeffrey Naber

Committee Member 1

Ezra Bar Ziv

Committee Member 2

Linda Wanless

Abstract

In this research work, a numerical model has been developed which predicts the oxidation of PM in the cake layer of the CPF present in a diesel engine aftertreatment system. A wall flow monolith model has been studied to understand the mechanism of different layers of a CPF and the research is focused on the cake layer. The cake layer has two sub layers – namely, layer 1 and layer 2. In this study, only layer 1 has been considered with no oxidation due to the catalysts.

The two mechanisms considered for oxidation of PM are oxidation of fixed and volatile carbon in the PM by NO2 assisted oxidation and thermal oxidation. The values of loading time, activation energies, frequency factors, temperature, mole fractions of O2 and NO2, volumetric flow rate and inlet concentration of PM are taken as inputs to the model from the literature. In the model generated results, the variation of the PM mass in, PM mass out, PM mass retained and PM mass oxidized in the cake layer with time has been plotted. The other graphs plotted from the model are variation of the thickness and the filtration efficiency of the PM cake layer with time. In order to validate the model, results from the experiments conducted by Kiran Premchand on a 2004 John Deere 6-cylinder, in-line, 6.8 liters turbo-charged and after-cooled engine were considered and these were compared with the results from the model.

After the model has been calibrated and validated with the experimental results, it is applied to other cases. The first case considered is the temperature sweep of the fraction of PM oxidized by NO2 and O2. The second case considered is the variation of the percentage of PM mass oxidized by the two mechanisms considered with time. From this, appropriate conclusions have been drawn.

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