Characterization, Design, And Optimization Of Dual-Purpose Wind Turbines And Frost Protection Fans,
2022
California Polytechnic State University, San Luis Obispo
Characterization, Design, And Optimization Of Dual-Purpose Wind Turbines And Frost Protection Fans, Ethan Narad
Master's Theses
This thesis report outlines the creation of a MATLAB tool to design reversible machines that can function as both wind turbines and as agricultural frost protection fans. Frost protection fans are used to prevent crop loss during radiative freeze events during which a temperature inversion is present. Such a dual-purpose machine fundamentally has the constraint that it must use symmetric airfoils, so a suite of tools for automatically designing an optimized wind turbine blade with symmetric airfoils using the Blade Element Momentum (BEM) theory approach is presented. The BEM code is then re-derived and adapted for use with a frost …
Characterization Of Effective Diffusion Within Viscoelastic Fluids With Elastic Instabilities,
2022
University of Alabama in Huntsville
Characterization Of Effective Diffusion Within Viscoelastic Fluids With Elastic Instabilities, Valerie Hietsch, Phillip Ligrani, Mengying Su
PRC-Affiliated Research
We considered effective diffusion, characterized by magnitudes of effective diffusion coefficients, in order to quantify mass transport due to the onset and development of elastic instabilities. Effective diffusion coefficient magnitudes were determined using different analytic approaches, as they were applied to tracked visualizations of fluorescein dye front variations, as circumferential advection was imposed upon a flow environment produced using a rotating Couette flow arrangement. Effective diffusion coefficient results were provided for a range of flow shear rates, which were produced using different Couette flow rotation speeds and two different flow environment fluid depths. To visualize the flow behavior within the …
Design And Development Of Active Flow Effectors,
2022
University of Alabama in Huntsville
Design And Development Of Active Flow Effectors, Konstantinos Kanistras
Summer Community of Scholars (RCEU and HCR) Project Proposals
No abstract provided.
Design And Development Of An Online Wind Tunnel,
2022
University of Alabama in Huntsville
Design And Development Of An Online Wind Tunnel, Konstantinos Kanistras
Summer Community of Scholars (RCEU and HCR) Project Proposals
No abstract provided.
Flame-Generated Turbulence For Flame Acceleration And Detonation Transition,
2022
University of Central Florida
Flame-Generated Turbulence For Flame Acceleration And Detonation Transition, Rachel Hytovick
Electronic Theses and Dissertations, 2020-2023
Detonations are a supersonic mode of combustion witnessed in a variety of applications, from next-generation propulsion devices to catastrophic explosions and the formation of supernovas. Detonations are typically initiated through the deflagration to detonation transition (DDT), a detailed process where a subsonic flame undergoes rapid acceleration increasing compressibility until a hotspot forms on the flame front inciting a detonation wave to form. Due to the complex nature of the phenomena, DDT is commonly investigated in three stages – (i) preconditioning, (ii) detonation onset, and (iii) wave propagation and stability. The research presented explores each of these stages individually, with a …
A Study Of Microgravity On Fluid Transport Through Porous Structures In Microfluidic Devices,
2022
University of Central Florida
A Study Of Microgravity On Fluid Transport Through Porous Structures In Microfluidic Devices, Sylvain Le Henaff
Electronic Theses and Dissertations, 2020-2023
The objective of this study is to refine the understanding of micro-fluidics subject to micro-gravity in an attempt to support future space exploration efforts. A combination of experimental and numerical approaches were utilized to build a validated assessment approach. A quasi-pore geometry, inspired by CT scans of rat bones, was used in lieu of human bone structures. A quasi-1D assessment of the conservation of momentum was used to identify the dominant forces acting on the fluid at the operating length-scales. The dominant forces were surface tension, gravity, and shear stress. Experiments were conducted to visualize the flow moving through the …
Interactions Of Aerosol Droplets With Ventilated Airflows In The Context Of Airborne Pathogen Transmission,
2022
University of Central Florida
Interactions Of Aerosol Droplets With Ventilated Airflows In The Context Of Airborne Pathogen Transmission, Steven Schroeder
Electronic Theses and Dissertations, 2020-2023
This multidisciplinary study provides a comprehensive visualization of airborne aerosols and droplets coming into contact with a crossflow of moving air utilizing both experimental particle measuring methods and multiphase computational fluids dynamics (CFD). The aim of this research is to provide a Eulerian visualization of how ventilation can alter the position and density of an aerosol cloud, with the goal of applying this information to our understanding of social distancing ranges within outdoor settings and ventilated rooms. The results indicate that even minor perpendicular crossflows across the trajectory of an aerosol cloud can greatly reduce both the linear displacement and …
The Effects Of Supersonic Reacting Flow Over A Wedge,
2022
University of Central Florida
The Effects Of Supersonic Reacting Flow Over A Wedge, Taylor R. Brown
Honors Undergraduate Theses
There is a growing need for a fundamental understanding of how detonations are formed and sustained as propulsion technology advances toward the use of detonation-based engines. The deflagration-to-detonation transition (DDT) phenomenon is studied to better understand both the fundamentals of detonation physics and the conditions surrounding how detonations are formed and sustained. This research aims to study the effects of a wedge on DDT and detonation formation. A hydrogen-air mixture is pumped into a chamber and ignited by a spark plug. Turbulence-driven flame acceleration is induced by turbulators in the chamber through which the flame propagates. The flame then flows …
Vibrations Of Rotationally Periodic Structures: A Metric For Mistuning Characterization And Vibration Localization,
2022
University of Central Florida
Vibrations Of Rotationally Periodic Structures: A Metric For Mistuning Characterization And Vibration Localization, Andres Rodriguez
Electronic Theses and Dissertations, 2020-2023
Blisk components are an integral part of jet engines and power generation systems. Composed of a single monolithic structure, integral blisks combine the blade-and-disk portion of primary components such as the fan, compressor stage, or turbine stage. This design modification increases the aerodynamic performance while decreasing the cost and eliminating time of assembly. However, these benefits come with the loss of blade-disk connection interfaces, which greatly reduces the structure's damping and its ability to attenuate unwanted structural vibrations. Blisk dynamics are impacted by mistuning, which is a disruption of the periodic symmetry of otherwise identical bladed sections. This disruption degrades …
Comparative Analysis Of Winglet Efficiency On Supercritical Versus Traditionally Cambered Airfoils,
2022
Georgia Southern University
Comparative Analysis Of Winglet Efficiency On Supercritical Versus Traditionally Cambered Airfoils, Evan Cathers
College of Graduate Studies: Theses & Dissertations
This study serves to define the performance of several industry-recognized and exploratory wing tip devices on aircraft wings utilizing contemporary supercritical airfoil geometry. For comparison, the same examination is performed on a wing comprised of traditionally cambered airfoils, the platform upon which winglets were initially developed. The supercritical wing design is based on that of the Airbus A320, while the conventional airfoil is based upon the Boeing 737-800 platform. Tip devices selected for analysis include blended, raked, split scimitar, fence, and spiroid winglets, as well as tip sails, characterized by the spreading of a bird’s primary flight feathers. Methodology for …
Sensitivity Of Combustion Liner Contour To Sand Ingestion Clogging,
2022
University of Central Florida
Sensitivity Of Combustion Liner Contour To Sand Ingestion Clogging, Nelson Padilla
Electronic Theses and Dissertations, 2020-2023
This currently presented work is an evaluation of the characteristics of different cooling hole geometries to particulate ingestion clogging. Experimentation was conducted using a premixed bluff body flame combustor facility to generate high temperature combustor flow conditions. Sand ingestion along the cooling path of the combustion liner was reproduced using an air-assisted seeder providing consistent sand ingestion. Mass flow rate of cooling air was controlled using a sonic orifice downstream of a pressure regulator so that the mass flow rate of the air and sand mixture is independent of the clogging state. Pressure data upstream of a small section of …
The Breakup Of Rp-2 Liquid Fuel Droplets In A Detonation Field,
2022
University of Central Florida
The Breakup Of Rp-2 Liquid Fuel Droplets In A Detonation Field, Daniel Dyson
Electronic Theses and Dissertations, 2020-2023
Experimentally obtained droplet breakup patterns are presented for RP-2 liquid fuel droplets in the environment behind a detonation wave. To the best of our knowledge, this data is the first of its kind to examine the fundamental interactions between detonation waves and an individual fuel droplet. The experiments presented here are expected to support the ongoing effort of creating accurate models of droplet breakup in a variety of environments, which in turn will lead to enhanced predictions of rotating detonation engine performance, improved safety considerations for facilities operating in hazardous conditions, and new knowledge in energetics, hypersonics, and explosion dynamics …
Recent Analytic Development Of The Dynamic Q-Tensor Theory For Nematic Liquid Crystals,
2022
Old Dominion University
Recent Analytic Development Of The Dynamic Q-Tensor Theory For Nematic Liquid Crystals, Xiang Xu
Mathematics & Statistics Faculty Publications
Liquid crystals are a typical type of soft matter that are intermediate between conventional crystalline solids and isotropic fluids. The nematic phase is the simplest liquid crystal phase, and has been studied the most in the mathematical community. There are various continuum models to describe liquid crystals of nematic type, and Q-tensor theory is one among them. The aim of this paper is to give a brief review of recent PDE results regarding the Q-tensor theory in dynamic configurations.
Autoignition Delay Time Measurements And Chemical Kinetic Modeling Of Hydrogen/Ammonia/Natural Gas Mixtures,
2022
University of Central Florida
Autoignition Delay Time Measurements And Chemical Kinetic Modeling Of Hydrogen/Ammonia/Natural Gas Mixtures, Jessica Baker
Electronic Theses and Dissertations, 2020-2023
In recent years, hydrogen-carrying compounds have accrued interest as an alternative to traditional fossil fuels due to their function as zero-emission fuels. As such, there is interest in investigating hydrogen-carrying compounds to improve understanding of the fuels' characteristics for use in high pressure systems. In the current study, the oxidation of ammonia/natural gas/hydrogen mixtures was carried out to study CO formation profiles as well as the ignition delay times behind reflected shock waves in order to refine chemical kinetic models. Experiments were carried out in the University of Central Florida's shock tube facility by utilizing chemiluminescence to obtain OH* emission …
Shock Tube And Gas Dynamic Design Considerations And Implementation For Extended Test Times,
2022
University of Central Florida
Shock Tube And Gas Dynamic Design Considerations And Implementation For Extended Test Times, Jacklyn Higgs
Electronic Theses and Dissertations, 2020-2023
A new shock tube test section has been designed and manufactured for the purpose of increasing the test time and expanding the applications of the shock tube for a multitude of ongoing and future projects. One purpose for the test section extension is to allow for flow visualization of droplets impacted by a shock wave for the interaction of hypersonic vehicles and atmospheric disturbances. Another purpose is to measure behind the incident shock to capture the chemical kinetics for a high-altitude environment and low-pressure, high-temperature space applications. This new test section contains 24 round optical ports for laser spectroscopy for …
Investigating The Effect Of Cmas Infiltration On Residual Stress Of High Temperature Ceramic Coatings For Turbine Engines Using 3d Confocal Raman Spectroscopy,
2022
University of Central Florida
Investigating The Effect Of Cmas Infiltration On Residual Stress Of High Temperature Ceramic Coatings For Turbine Engines Using 3d Confocal Raman Spectroscopy, Zachary Stein
Electronic Theses and Dissertations, 2020-2023
Calcium-magnesium-aluminosilicates (CMAS), such as sand or volcanic ash, are ingested by aircraft jet engines during operation. CMAS then becomes molten while traveling through the combustor of the engine before depositing onto turbine blades within the turbine section of the engine. The molten CMAS melt infiltrates and interacts with the high temperature ceramic coated turbine blades. This infiltration increases coating stiffness and promotes coating phase destabilization, encouraging micro-crack formation and increasing the risk of spallation. Thermomechanical effects from CMAS infiltration were mapped over time with confocal Raman spectroscopy. The residual stresses within infiltrated 7YSZ EB-PVD coatings were captured with microscale resolution. …
A Decoupled Engineering Methodology For Accurate Prediction Of Ablative Surface Boundary Conditions In Thermal Protection Systems,
2022
University of Kentucky
A Decoupled Engineering Methodology For Accurate Prediction Of Ablative Surface Boundary Conditions In Thermal Protection Systems, Justin Cooper
Theses and Dissertations--Mechanical and Aerospace Engineering
The main objective of the present work is to demonstrate a method for prediction of aerothermal environments in the engineering design of hypersonic vehicles as an alternative to the current heritage method. Flat plate and stagnation point boundary layer theory require multiple assumptions to establish the current engineering paradigm. Chief among these assumptions is the similarity between mass and heat transfer. Origins of these assumptions are demonstrated and their relationship to conservative engineering design is analyzed, as well as conditions where they possibly break down. An alternative approach for assessing aerothermal environments from the fluid domain is presented, which permits …
Numerical And Scaling Study On Application Of Inkjet Technology To Automotive Coating,
2022
University of Kentucky
Numerical And Scaling Study On Application Of Inkjet Technology To Automotive Coating, Masoud Arabghahestani Dr.
Theses and Dissertations--Mechanical and Aerospace Engineering
A thorough literature review identified lack of precision control over quality of droplets generated by the currently available industrial sprayers and a growing need for higher quality droplets in the coating industry. Particularly, lack of knowledge and understanding in continuous inkjets (CIJ) and drop-on-demand (DOD) technologies is identified as significant. Motivated by these needs, this dissertation is dedicated to computational fluid dynamics (CFD) and scaling studies to improve existing inkjet technologies and develop new designs of efficient coating with single and/or multiple piezoelectric sensors to produce on-demand droplets. This dissertation study aims at developing a new DOD type coating technology, …
Experimental Investigation Of Roughness And Blowing Effects Over Ablator-Like Surfaces,
2022
University of Kentucky
Experimental Investigation Of Roughness And Blowing Effects Over Ablator-Like Surfaces, Colby Borchetta
Theses and Dissertations--Mechanical and Aerospace Engineering
Two separate experiments using PIV were carried out to investigate the effects of
roughness and blowing over surfaces geometrically similar to ablation materials used for atmospheric re-entry. The first, water tunnel experiments, employed a dimpled surface similar to AVCOAT, while the second set was completed in a wind tunnel with a material similar to PICA. For the first set, the flow with blowing becomes destabilized, and more disorganized. The blowing disrupts the relatively simple vorticity shedding process and significantly modifies momentum transport via interaction of detached structures. Flow structure and their modifications were examined with a sPOD analysis. The focus …
Quantification Of The Aerodynamic Drivers Of A Deployable Propeller,
2022
University of Central Florida
Quantification Of The Aerodynamic Drivers Of A Deployable Propeller, David Malyszek
Electronic Theses and Dissertations, 2020-2023
With the use deployable drones becoming more common research into their improvement is necessary. Deployable drones that are launched from tubes have size limits on the diameter of the propeller during launch and storage. The purpose of this research is to develop deployable propeller blades for practical uses, such as tube launched propeller driven drones and easier to transport wind turbine blades. A deployable propeller will allow for the utilization of larger propellers when a large non-deployable blade isn't an option. Because deployable propellers need to fold, the deployable propeller blades were designed to be hollow and with a slit …
