Date of Completion

7-8-2015

Embargo Period

7-6-2015

Keywords

combustion, optical diagnostics, turbulence

Major Advisor

Michael W. Renfro

Associate Advisor

Baki M. Cetegen

Associate Advisor

Chih-Jen Sung

Field of Study

Mechanical Engineering

Degree

Doctor of Philosophy

Open Access

Open Access

Abstract

Despite the movement toward alternative and renewable energy sources, combustion is still responsible for the majority of energy production in the world. Thus, there is a need for measurements in canonical and practical flames, the results of which are used to improve modeling efforts. Laser and optical diagnostics are the benchmark of combustion research, but obtaining temporally- and spatially-resolved multi-scalar measurements in turbulent flows is complex and expensive. Measurements in practical burners present an additional challenge of optical access, which limits the number and type of diagnostics which may be used.

This work describes the development of several optical techniques for the study of combustion, including three dimensional structures, turbulent combustion, and extinction. A Cassegrain optical system and maximum entropy deconvolution method are used to produce spatially-resolved chemiluminescence images of a three-dimensional flow field. Abel inversion is used to recover spatially-resolved temporal statistics from a turbulent jet. Finally, a local extinction event is studied via various optical and modeling methods. The feasibility of indirectly measuring scalar dissipation rate in the presence of a local extinction event via laser-induced fluorescence (LIF) of a single scalar – formaldehyde – is examined, and the results are used in conjunction with computational fluid dynamics results to draw conclusions about the effect of heat transfer through an extinction edge.

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