Masters Theses


Adam Neer


"The size, morphology and volume fraction of sub-micron particulate matter emitted from a compression ignition (diesel) engine was investigated using thermophoretic sampling experiments followed by direct visual characterizations under transmission electron microscopy. Specifically, measurements were conducted at the exhaust of a 6059T John Deere, 5.9 L, 6 cylinder, turbocharged, direct injection diesel engine. The particles observed were composed of nearly spherical primary particles (spherules) that formed aggregates of various sizes and shapes. The size distributions of spherules and aggregates were separately measured to obtain the available surface area, which is crucial for estimating the environmental and health impact of particles. Aggregate fractal dimensions and prefactors were also quantified. Different engine speeds and relative loads were considered to determine the effects of typical engine operating conditions on the particulate properties. The present mean spherule diameters were in the range of 20-35 nm while the mean aggregate diameters were in the range of 160 to 350 nm. 98% of the measured aggregates were smaller than a gyration diameter of 1 µm; indicating that the current regulations based on PM(2.5) may be insufficient. Fractal dimensions and prefactors were in the range of 1.77 ± 0.14 and 1.8 ± 0.5, respectively, characteristics of the cluster-cluster aggregation mechanism. These fractal properties are consistent with the numerous past studies in various laboratory flames and a recent study in another diesel engine. Soot volume fractions were also estimated based upon thermophoretic sampling experiments developed from laboratory flames. These measurements implemented for the first time in a diesel engine yielded soot volume fractions on the order of 0.001 to 0.01 ppm"--Abstract, page iii.


Köylü, Ümit Ö. (Ümit Özgür)

Committee Member(s)

Drallmeier, J. A.
Whitefield, Philip D.


Mechanical and Aerospace Engineering

Degree Name

M.S. in Mechanical Engineering


University of Missouri--Rolla

Publication Date

Summer 2005

Journal article titles appearing in thesis/dissertation

NASA-UMR Center of Excellence for Particulate Emissions Reduction Program


ix, 59 pages

Note about bibliography

Includes bibliographical references (pages 57-58).


© 2005 Adam Neer, All rights reserved.

Document Type

Thesis - Open Access

File Type




Subject Headings

Diesel motor exhaust gas -- Measurement

Thesis Number

T 8758

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