Experimental study of laminar and turbulent flame stabilization using laser diagnostics

Date of Completion

January 2009

Keywords

Engineering, Mechanical

Degree

Ph.D.

Abstract

An increased understanding of various flame stabilization mechanisms has been achieved by the implementation of laser diagnostic techniques. Combustion investigations in this work have ranged from the understanding of fundamental combustion, with work performed on neighboring edge flame stabilization to more application oriented investigations. Applications involve the understanding of a stabilization technique currently used in gas turbine augmenters, bluff body stabilized flames, and one that may be the future of gas turbine combustors, the Ultra Compact Combustor (UCC), which utilizes cavity stabilized flames. ^ Through a combination of Rayleigh scattering imaging and planar laser induced fluorescence (PLIF) neighboring edge flames were found to stabilize dominantly based on conditions upstream of each individual flame based on information regarding the concentration gradients upstream of each flame and qualitative heat release of each flame.^ PLIF was also implemented in combination with particle image velocimetry and high speed imaging, to understand the blow off behavior of bluff body stabilized flames. Strain information and flame locations, of near blow off flames showed that near blow off flame fronts became increasingly strained leading to local extinction points and possibility of a transition to recirculation zone burning, both dynamics which can provide useful for the future development of controls to prevent blow off. Flame location measurements provided information for use to further develop the UCC so that implementation will provide optimal conditions within a gas turbine. Through application of diagnostics within these various regimes improvements to some of the diagnostics have been made to help those in the future with combustion measurements.^

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