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Articles 1 - 12 of 12
Full-Text Articles in Engineering
The Subject Librarian Newsletter, Engineering And Computer Science, Spring 2018, Buenaventura "Ven" Basco
The Subject Librarian Newsletter, Engineering And Computer Science, Spring 2018, Buenaventura "Ven" Basco
Libraries' Newsletters
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Influence Of Transverse Slot Jet On Premixed Flame Acceleration, Dylan Tarrant
Influence Of Transverse Slot Jet On Premixed Flame Acceleration, Dylan Tarrant
Electronic Theses and Dissertations
This work aims to identify the key flow parameters that influence flame acceleration in a semi-confined square channel. A transverse fluidic jet was used as an active flow blockage mechanism and to introduce turbulence into the propagating flame. Three experimental parameters were used to examine the relative influence of (1) mixture reactivity defined here as system equivalence ratio (SER), (2) jet mixture composition (JMC), and the momentum ratio (MR) on the acceleration of laminar premixed methane flame. High-speed PIV and schlieren photography were utilized to characterize the instantaneous flow-field conditions throughout the flame-jet interaction. Using these diagnostic techniques, flame front …
Compressible Turbulent Flame Speed Of Highly Turbulent Standing Flames, Jonathan Sosa
Compressible Turbulent Flame Speed Of Highly Turbulent Standing Flames, Jonathan Sosa
Electronic Theses and Dissertations
This work presents the first measurement of turbulent burning velocities of a highly-turbulent compressible standing flame induced by shock-driven turbulence in a Turbulent Shock Tube. High-speed schlieren, chemiluminescence, PIV, and dynamic pressure measurements are made to quantify flame-turbulence interaction for high levels of turbulence at elevated temperatures and pressure. Distributions of turbulent velocities, vorticity and turbulent strain are provided for regions ahead and behind the standing flame. The turbulent flame speed is directly measured for the high-Mach standing turbulent flame. From measurements of the flame turbulent speed and turbulent Mach number, transition into a non-linear compressibility regime at turbulent Mach …
Structured Light-Field Focusing 3d Density Measurements Of A Supersonic Cone, Ryonosuke Ozawa
Structured Light-Field Focusing 3d Density Measurements Of A Supersonic Cone, Ryonosuke Ozawa
Electronic Theses and Dissertations
This study describes three-dimensional (3D) quantitative visualization of density field in a supersonic flow around a cone spike. A measurement of the density gradient is conducted within a supersonic wind tunnel facility at the Propulsion and Energy Research Laboratory at the University of Central Florida utilizing Structured Light-Field Focusing Schlieren (SLLF). In conventional schlieren and Shadowgraph techniques, it is widely known that a complicated optical system is needed and yet visualizable area depends on an effective diameter of lenses and mirrors. Unlike these techniques, SLLF is yet one of the same family as schlieren photography, it is capable of non-intrusive …
Characterization Of Acoustic Modes In Aeroengines, Michelle Otero
Characterization Of Acoustic Modes In Aeroengines, Michelle Otero
Electronic Theses and Dissertations
Acoustic instabilities remain a key design concern faced in the development of liquid rocket engines. The interaction between the acoustic modes and the occurring combustion reactions can be detrimental to the engine. The fluctuating pressure waves resulting from the flame oscillations in the system can potentially lead to engine failure. For this reason, research in acoustic instabilities and methods to minimize the influences on the engine, has maintain interest in the aerospace community. The scope of this study was to design, optimize and characterize acoustic behaviors of a scaled rocket combustion chamber simulating acoustic pressure waves. Tangential and longitudinal acoustic …
The Effect Of Martensite-Fractions Assumptions In Shape Memory Alloy Springs, Christian Vazquez
The Effect Of Martensite-Fractions Assumptions In Shape Memory Alloy Springs, Christian Vazquez
Electronic Theses and Dissertations
This research addresses various models of a spring-mass system that uses a spring made of a shape memory alloy (SMA). The system model describes the martensite fractions, which are values that describe an SMA's crystalline phases, via differential equations. The model admits and this thesis contrasts two commonly used but distinct assumptions: a homogeneous case where the martensite fractions are constant throughout the spring's cross section, and a bilinear case where the evolution of the martensite fractions only occurs beyond some critical radius. While previous literature has developed a model of the system dynamics under the homogeneous assumption using the …
The Exploration Of Rotating Detonation Dynamics Incorporating A Coal-Based Fuel Mixture, John P. Rogan
The Exploration Of Rotating Detonation Dynamics Incorporating A Coal-Based Fuel Mixture, John P. Rogan
Honors Undergraduate Theses
This investigation explores the detonation dynamics of a rotating detonation engine (RDE). Beginning with the general understanding and characteristics of hydrogen and compressed air as a detonation fuel source, this study further develops the experimental approach to incorporating a coal-based fuel mixture in an RDE. There is insufficient prior research investigating the use of coal as part of a fuel mixture and insignificant progress being made to improve thermal efficiency with deflagration. The U.S. Department of Energy's Office of Fossil Energy awarded the Propulsion and Energy Research Laboratory at the University of Central Florida a grant to lead the investigation …
Mechanisms Of Lean Flame Extinction, Ian M. Lasky
Mechanisms Of Lean Flame Extinction, Ian M. Lasky
Honors Undergraduate Theses
Lean flame blowout is investigated experimentally within a high-speed combustor to analyze the temporal extinction dynamics of turbulent premixed bluff body stabilized flames. The lean blowout process is induced through fuel flow reduction and captured temporally using simultaneous high-speed particle imaging velocimetry (PIV) and CH* chemiluminescence. The evolution of the flame structure, flow field, and the resulting strain rate along the flame are analyzed throughout extinction to distinguish the physical mechanisms of blowout. Flame-vortex dynamics are found to be the main driving mechanism of flame extinction; namely, a reduction of flame-generated vorticity coupled with an increase of downstream shear layer …
Optimal Sintering Temperature Of Ceria-Doped Scandia Stabilized Zirconia For Use In Solid Oxide Fuel Cells, Amanda K. Assuncao
Optimal Sintering Temperature Of Ceria-Doped Scandia Stabilized Zirconia For Use In Solid Oxide Fuel Cells, Amanda K. Assuncao
Honors Undergraduate Theses
Carbon emissions are known to cause decay of the Ozone layer in addition to creating pollutant, poisonous air. This has become a growing concern among scientists and engineers across the globe; if this issue is not addressed, it is likely that the Earth will suffer catastrophic consequences. One of the main culprits of these harmful carbon emissions is fuel combustion. Between vehicles, power plants, airplanes, and ships, the world consumes an extraordinary amount of oil and fuel which all contributes to the emissions problem. Therefore, it is crucial to develop alternative energy sources that minimize the impact on the environment. …
Theoretical Paschen's Law Model For Aerospace Vehicles: Validation Experiment, Jaysen Mulligan Aroche
Theoretical Paschen's Law Model For Aerospace Vehicles: Validation Experiment, Jaysen Mulligan Aroche
Electronic Theses and Dissertations
Aerospace vehicles often experience triboelectric charging while traversing the atmosphere. Triboelectric charging occurs when a material come into frictional contact with a different material. Aerospace vehicles triboelectrically charge due to frictional contact with dust and ice crystals suspended in the atmosphere. Launch vehicles traversing ice clouds in low-pressure atmosphere are especially prone to electrostatic discharge events (i.e. sparks). These conditions are hazardous and affect the vehicle's launch commit criteria. In 2010, engineers from an ARES-I rocket launch reported concerns with triboelectric charging over their self-destruct system antenna. This concern was addressed by putting the antenna through harsh conditions in a …
Analysis Of Heat Transfer On Turbulence Generating Ribs Using Dynamic Mode Decomposition, Michael Elmore
Analysis Of Heat Transfer On Turbulence Generating Ribs Using Dynamic Mode Decomposition, Michael Elmore
Electronic Theses and Dissertations
Ducts with turbulence-promoting ribs are common in heat transfer applications. This study uses a recent modal extraction technique called Dynamic Mode Decomposition (DMD) to determine mode shapes of the spatially and temporally complex flowfield inside a ribbed duct. One subject missing from current literature is a method of directly linking a mode to a certain engineering quantity of interest. Presented is a generalized methodology for producing such a link utilizing the data from the DMD analysis. Theory suggests exciting the modes which are identified may cause the flow to change in such a way to promote the quantity of interest, …
Flow Control Of Tandem Cylinders Using Plasma Actuators, Jonah Larsen
Flow Control Of Tandem Cylinders Using Plasma Actuators, Jonah Larsen
Honors Undergraduate Theses
The flow over a set of tandem cylinders at a moderate Reynolds numbers (Re), and with different separation lengths has been studied. Two dimensional (2D) and three-dimensional (3D) plasma actuators were used to control the flow over the leading cylinder to change the vortex shedding, and subsequently the flow on the second cylinder. The 3D plasma actuator was segmented along the length of the cylinder with a spacing of λ = 4 while the 2D actuator simply ran straight down the span of the cylinder. Particle image velocimetry (PIV) measurements were used to investigate the flow along the central plane …