Spray Flame and Exhaust Jet Characteristics of a Pressurized Swirl Combustor

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dc.contributor.advisorGupta, Ashwani Ken_US
dc.contributor.authorLinck, Martin Brendanen_US
dc.contributor.departmentMechanical Engineeringen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2006-06-14T06:11:05Z
dc.date.available2006-06-14T06:11:05Z
dc.date.issued2006-05-17en_US
dc.description.abstractThis work describes an investigation of swirl-stabilized flames, created in a combustor featuring co-annular swirling airflows, under unenclosed, enclosed, and submerged conditions. A centrally-located fuel nozzle, which uses air-assist atomization, creates a methanol fuel spray. This approach provides great control over fuel spray properties in a compact geometry. Factors affecting the structure of the flames, including the effect of the central atomization air jet, are investigated using three-dimensional particle image velocimetry, direct imaging, and phase-Doppler particle analysis techniques. Exhaust jet temperatures are measured. The dynamic events affecting two-phase exhaust jets from the combustor under submerged conditions are examined using high-speed cinematography and sound spectrum analysis. It is found that the structures of the flames examined, which feature low overall equivalence ratios, are closely linked to the features of the air flowfield in the combustor. Swirl numbers of flows emerging from twisted-vane swirl assemblies are characterized. The structure of the flow is affected by the swirl configuration, but does not depend heavily on the Reynolds number. The central atomization air jet (with or without fuel) reshapes the recirculation region in the swirling flow and has a significant, controllable effect on the structure of the airflow and flame. The effect is the same for nonreacting and reacting flows. In one unique case, the central atomization air interacts with the swirling flow to create two recirculation regions and a lifted flame. The lifted flame is more compact than similar non-lifted flames. The twin-fluid atomization approach is shown to provide effective atomization over a wide range of operating conditions. The two-phase interaction of the exhaust jet is found to depend on the pressure drop over the exhaust nozzle. The dynamic behavior of the exhaust jet is buoyancy-driven at low pressure drops, and is affected by complex instability mechanisms at high pressure drops. Strouhal numbers of large-scale unstable events occurring in the two-phase flow are two orders of magnitude smaller than those associated with instabilities in single-phase flows. Evidence is presented, indicating that acoustic pressure waves in the exhaust jet may be involved in the generation of bubbles surrounding exhaust jets at high pressure drops.en_US
dc.format.extent5074155 bytes
dc.format.mimetypeapplication/pdf
dc.identifier.urihttp://hdl.handle.net/1903/3627
dc.language.isoen_US
dc.subject.pqcontrolledEngineering, Mechanicalen_US
dc.subject.pqcontrolledEngineering, Aerospaceen_US
dc.subject.pqcontrolledEngineering, Chemicalen_US
dc.subject.pquncontrolledSwirl Stabilized Combustionen_US
dc.subject.pquncontrolledTwin Fluid Atomizationen_US
dc.subject.pquncontrolledParticle Image Velocimetryen_US
dc.subject.pquncontrolledTwo-Phase Flowen_US
dc.subject.pquncontrolledGas Turbineen_US
dc.subject.pquncontrolledUnderwateren_US
dc.titleSpray Flame and Exhaust Jet Characteristics of a Pressurized Swirl Combustoren_US
dc.typeDissertationen_US

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