Mechanical Engineering Commons^™

Heat Transfer And Pressure Measurements From Jet Array Impingement Onto A Large Radius Curved Surface, John Harrington

Electronic Theses and Dissertations

This study investigates the heat transfer and pressure drop characteristics of jet array impingement in two distinct parts. In the first part, the performance of a uniform array of jets on both a flat and a large radius curved target surface are compared. This comparison was done at average jet Reynolds number ranging from 55,000 to 125,000. In the second part, the characteristics of a non-uniform array of jets, more typical of geometries used in actual gas turbine combustors, are investigated, including the effects of the removal of downstream rows and the placement of rib features onto the target surface. …

Transient Cfd Analysis Of Autorotation Using Hybrid Les And Adaptive Mesh Morphing Techniques, Patricia Coronado Domenge

Electronic Theses and Dissertations

Large-Eddy Simulation (LES) based turbulence modeling is a developing area of research in Fluid-Structure Interaction (FSI). There is considerable scope for further scientific research in this field and this dissertation aims to extend it to the study of flow-induced motion. The emphasis of this work is on autorotation, an important category of flow-induced motion that is commonly seen in energy applications such as wind turbines and in aviation applications such as the autogyro. In contrast to existing works on FSI that typically assume prescribed motion of structures in a flow field, this research develops LES based FSI studies for large-scale …

Shock Tube And Mid-Infrared Laser Absorption Measurements Of Ignition Delay Times And Species Time-Histories, Batikan Koroglu

Electronic Theses and Dissertations

Energy consumption has increased dramatically as the world advances and becomes more industrialized. Over the next twenty five years, the U.S. Department of Energy expects the energy demand to increase by 29% with majority of the new energy coming from natural gas (methane). Another promising fuel source for power generation and transportation is the biofuels. The biofuel use in the US is shown to have increased substantially in the last decade. There are serious environmental concerns associated with greenhouse (e.g. carbon-dioxide) and toxic gas emissions (e.g. nitrogen oxides and aldehydes such as propanal) due to deriving energy from natural gas …

Structural Health Monitoring Of Composite Overwrapped Pressure Vessels, Luca Letizia

Honors Undergraduate Theses

This work is focusing to study the structural behavior of Composite Overwrapped Pressure Vessels (COPVs). These COPVs are found in many engineering applications. In the aerospace field, they are installed onto spaceships and aid the reorientation of the spacecraft in very far and airless, therefore frictionless, orbits to save energy and fuel. The intent of this research is to analyze the difference in performance of both perfectly intact and purposely damaged tanks. Understanding both the source and location of a structural fault will help NASA engineers predict the performance of COPVs subject to similar conditions, which could prevent failures of …

An Experimental Investigation Of Heat Transfer For Arrays Of Impingement Jets Onto The Featured Surfaces With Cylindrical And Elliptical Raised Surfaces, Marc A. Medina

Honors Undergraduate Theses

This study focuses on multi-jet impingement for gas turbine geometries in which the objective is to understand the influence of the roughness elements on a target surface to the heat transfer. Current work has proven that implementing roughness elements for multi-jet impingement target surfaces has increased heat transfer ranging anywhere from 10-30%. This study has chosen to investigate three different roughness elements, elliptical in cross-section, to compare to smooth surface geometries for multi-jet impingement. An experimental was taken for this study to extend the current knowledge of multi-jet impingement geometries and to further understand the heat transfer performance. A temperature …

The Mechanical Response And Parametric Optimization Of Ankle-Foot Devices, Kevin Smith

Electronic Theses and Dissertations

To improve the mobility of lower limb amputees, many modern prosthetic ankle-foot devices utilize a so called energy storing and return (ESAR) design. This allows for elastically stored energy to be returned to the gait cycle as forward propulsion. While ESAR type feet have been well accepted by the prosthetic community, the design and selection of a prosthetic device for a specific individual is often based on clinical feedback rather than engineering design. This is due to an incomplete understanding of the role of prosthetic design characteristics (e.g. stiffness, roll-over shape, etc.) have on the gait pattern of an individual. …

Dynamic Modeling Of Autorotation For Simultaneous Lift And Wind Energy Extraction, Sadaf Mackertich

Electronic Theses and Dissertations

The goal of this thesis is to develop a multi-body dynamics model of autorotation with the objective of studying its application in energy harvesting. A rotor undergoing autorotation is termed an Autogyro. In the autorotation mode, the rotor is unpowered and its interaction with the wind causes an upward thrust force. The theory of an autorotating rotorcraft was originally studied for achieving safe flight at low speeds and later used for safe descent of helicopters under engine failure. The concept can potentially be used as a means to collect high-altitude wind energy. Autorotation is inherently a dynamic process and requires …

Non-Dispersive Infrared (Ndir) Gas Sensor Utilizing Light-Emitting-Diodes Suitable For Applications Demanding Low-Power And Lightweight Instruments, Kyle Thurmond

Electronic Theses and Dissertations

Gas sensors that are low-power, light-weight, and rugged, while also remaining low-cost, have considerable appeal to areas from automotive to space flight. There are increasing demands for higher efficient vehicles with lower emissions in order meet regulations that are meant to mitigate or lessen the effects of climate change. An affordable, fast response sensor that can measure transient carbon monoxide (CO) and carbon dioxide (CO2) has broad application which can lead to more efficient, fuel flexible engines and regulations of harmful emissions. With compact, economical, low-power sensors that are able to continually monitor gases that are characteristic of burning materials, …

Study On Anisotropic Plasticity And Fracture Of Lightweight Metal Sheets, Yueqian Jia

Electronic Theses and Dissertations

How to reduce weight and increase fuel efficiency is a critical challenge in transportation industries. One way to resolve the problem is to adopting lightweight alloys (i.e. advanced high strength steel, aluminum alloys, or magnesium alloy) in structure designs and manufacturing. Fully understanding the mechanical properties of these materials is a key step. In order to fully characterize the plasticity and fracture of magnesium AZ31B-H24 sheets, a set of mechanical experiments (170 in total) were performed under both monotonic and non-proportional loading conditions, including monotonic uniaxial tension, notch tension, in-plane uniaxial compression, wide compression (or called biaxial compression), plane strain …

Characterization Of Slm-Manufactured Turbine Blade Microfeatures From Superalloy Powders, Brandon Ealy

Electronic Theses and Dissertations

The limits of gas turbine technology are heavily influenced by materials and manufacturing capabilities. Inconel remains the material of choice for most hot gas path (HGP) components in gas turbines, however recent increases in turbine inlet temperature (TIT) are associated with the development of advanced convective cooling methods and ceramic thermal barrier coatings. Increasing cycle efficiency and cycle specific work are the primary drivers for increasing TIT. Lately, incremental performance gains responsible for increasing the allowable TIT have been made mainly through innovations in cooling technology, specifically convective cooling schemes. An emerging manufacturing technology may further facilitate the increase of …

Catalytically Enhanced Heterogeneous Combustion Of Methane, Anthony Terracciano

Electronic Theses and Dissertations

Heterogeneous combustion is an advanced internal combustion technique, which enables heat recuperation within the flame by utilizing a highly porous ceramic media as a regenerator. Heat released within the gas phase convectively transfers to the solid media. This heat within the solid media then travels towards the inlet, enabling reactant preheating. Such heat redistribution enables stable burning of both ultra-lean fuel/air mixtures, forming a more diffuse flame through the combustion chamber, and results in reduced pollutant formation. To further enhance heterogeneous combustion, the ceramic media can be coated with catalytically active materials, which facilitates surface based chemical reactions that could …

Investigation Of Real Gas Effects On Centrifugal Compressor Analytical Methods For Supercritical Co2 Power Cycles, Lauren Blanchette

Electronic Theses and Dissertations

As supercritical carbon dioxide (sCO2) power cycles have shown potential to be the next generation power cycle, an immense amount of research has gone into developing this system. One of the setbacks facing development and optimization of this cycle is the unknown in current design and analysis methods ability to accurately model turbomachinery working with sCO2. Due to the desired inlet conditions to the compressor close proximity to the critical point, accurate design and analysis of this power cycle component is one of the main concerns. The present study provides aerodynamic analysis of a centrifugal compressor impeller blade with sCO2 …

Aeroelastic Investigation Of A Circumferentially Varying Tip Gap In An Axial Compressor Rotor, Ornan David Canon

Electronic Theses and Dissertations

The tip leakage flow in axial compressors is a significant factor in engine performance and a subject of investigation over the last several decades. Many studies have already shown that the vortices generated by this tip leakage can have a negative impact on the surrounding flow field and overall performance, and could potentially lead to excitations as well. This study examines the effect of these vortices on aeroelasticity. Specifically, it looks at the effect from a circumferentially varying tip gap, such as that produced by casing ovalization. For this project, the casing ovalization of an industrial gas turbine compressor was …

The Effect Of Vibrations On Cryogens Boil Off During Launch, Transfer And Transport, Erin Schlichenmaier

Electronic Theses and Dissertations

Boil-off of a cryogenic fluid which is caused by the temperature difference between the fluid and its environment is a phenomenon which has long been studied and is well understood. However, vibrational excitation of a cryogenic storage tank and the fluid inside it also play a role in the loss of cryogens. Mechanical energy applied to the system in the form of vibrational input is converted into thermal energy via viscous damping of the fluid. As a result, when a storage tank full of cryogenic fluids is vibrated, it boils off at an increased rate. A series of experiments were …

Fundamental Understanding Of Interactions Among Flow, Turbulence, And Heat Transfer In Jet Impingement Cooling, Md. Jahed Hossain

Electronic Theses and Dissertations

The flow physics of impinging jet is very complex and is not fully understood yet. The flow field in an impingement problem comprised of three different distinct regions: a free jet with a potential core, a stagnation region where the velocity goes to zero as the jet impinges onto the wall and a creation of wall jet region where the boundary layer grows radially outward after impinging. Since impingement itself is a broad topic, effort is being made in the current study to narrow down on three particular geometric configurations (a narrow wall, an array impingement configuration and a curved …

Forced Convection Cooling Of Electric Motors Using Enhanced Surfaces, Mohammed Almaghrabi

Electronic Theses and Dissertations

Electric motors are extensively engaged in industrial and commercial applications such as electrical cars, energy-conversion systems, elevators, and actuators for aircrafts. Due to the significant internal heat generation, it is usually a challenge to design and manufacture high power density, high reliability, and low cost electric motors with superior performance. One of the efficient ways to dissipate the heat generated in the electrical motor is by using extended surfaces (i.e. heat sinks). These surfaces are extruded from the motor casing and air is forced though them by a cooling fan. This cooling approach is simple to be implemented and has …

A Multi-Scale Approach To Study Solid Oxide Fuel Cells: From Mechanical Properties And Crystal Structure Of The Cell's Materials To The Development Of An Interactive And Interconnected Educational Tool, Amjad Aman

Electronic Theses and Dissertations

Solid Oxide Fuel Cells are energy conversion devices that convert chemical energy of a fuel directly into electrical energy. They are known for being fuel-flexible, have minimal harmful emissions, ideal for combined heat and power applications, highly energy-efficient when combined with gas or steam turbines. The current challenges facing the widespread adoption these fuel cells include cost reduction, long-term testing of fully integrated systems, improving the fuel cell stack and system performance, and studies related to reliability, robustness and durability. The goal of this dissertation is to further the understanding of the mechanical properties and crystal structure of materials used …

Optimal Switch Timing For Piezoelectric-Based Semi-Active Vibration Reduction Techniques, Christopher Kelley

Electronic Theses and Dissertations

Semi-active vibration reduction techniques switch a piezoelectric transducer between an open circuit and a shunt circuit in a way that reduces vibration. The steady-state vibration amplitude is reduced by exploiting the change in stiffness between states, manipulating the converted electrical energy, or both. Semi-active techniques typically require four switches per vibration cycle. Control laws such as state switching and synchronized switch damping require switches to occur at every displacement extrema. Due to the complexity of analyzing a system with discrete switches, these control laws were developed based on intuition. The few analyses that attempt to determine an optimal switching law …

Implications Of Electric Vehicles On Gasoline Tax Revenues, Florida Solar Energy Center, Kevin Schleith

FSEC Energy Research Center®

This report summarizes the results of research conducted to determine if current and near future EV sales will have an impact on gasoline (gas) tax revenues as part of the Federal Highway Trust Fund (HTF). Gasoline taxes account for $31.1 billion or about 87% of the HTF. The project results were accomplished through a review of existing industry and government reports that detail fuel tax revenues and through analysis of EV sales from 2010 to 2015.

Development Of A Set Of Force Response Equations To Represent The Musculature In Infants To Study Development Dysplasia Of The Hip, Brendan Jones

HIM 1990-2015

This paper describes how a force response equation was created to model muscles, tendons, and ligaments of the hip joint to improve a biomechanical model of an infant hip to study Developmental Dysplasia of the Hip (DDH). DDH is the most common abnormality in newborn infants and is defined as any amount of instability in the hip including complete dislocation. Researchers at our institution are attempting to increase the success rate of treatment methods by creating computer models of the biomechanics of infant hip instability and dislocation. The computer model used a scaled adult pelvis, femur, tibia, fibula and foot …

Design Of A Physical Windkessel Model For Use In Lvad In-Vitro Benchtop Modeling, Kyle W. Beggs

HIM 1990-2015

Despite improved life expectancy compared to medical management alone, Ventricular Assist Device (VAD) recipients show survival rates of 80% at 12 months and 70% at 24 months. A large portion of VAD-associated mortality results from increased risk of stroke with an event frequency reported between 14-47%. Recent concerns have been raised about unprecedented increases of thrombus formation in VAD recipients with subsequent reports pointing towards implantation techniques as a critical contributor to these events. Thus, the overall prognosis with mechanical support can improve by advancing the surgeon’s approach to VAD implantation. Previous studies using Computational Fluid Dynamics (CFD) were aimed …

Effects Of Binary Solvent System On Morphology Of Particles, Patrick Besana

HIM 1990-2015

Recent advancements in cancer research has led to the synthesis of a new drug known as docetaxel. Meant to replace paclitaxel, its more natural counterpart whose ingredients are difficult to obtain, the drug is known to effectively treat a wide array of cancers, including breast cancer, ovarian cancer, and prostate cancer. The establishment of a synthetic alternative to paclitaxel has increased its bioavailability, thereby lowering the cost needed to utilize the drug. Still, the limiting factor in minimizing costs is the method in which the drug is processed. Current methods in drug processing have their limitations, which include the introduction …

Semi-Annual Program Progress Performance Report For University Transportation Systems, Pppr#4, October 2015, Florida Solar Energy Center, David L. Block

FSEC Energy Research Center®

A summary of the major activities reported in the following pages is as follows. In the research area, the collection and analysis of data from the Nissan funded DC fast charger at FSEC (Project #3), the development of a student and faculty battery laboratory at Tuskegee University (Project #8), the opening of a new University of Hawaii battery test lab (Project #9), a computer model to optimize electrical costs for Tallahassee StarMetro buses (Project #14), and the installation and beginning of data collection from the FSEC wireless charging laboratory (Project #15). Detailed industry interactions for the period included Nissan, NovaCharge, …

Why Doesn't 25 Years Of An Evolving Energy Code Make More Of A Difference?, Florida Solar Energy Center, Charles Withers, Jr.

FSEC Energy Research Center®

This paper was presented at the 2015 Behavior, Energy and Climate Change Conference (BECC). New and more stringent building energy codes are implemented with the assumption and expectation that significant energy conservation will occur. While simulation and various analysis methodologies may be reasonably sound at estimating the energy impact, the actual impact is largely dependent upon new code enforcement and occupant behavior. This work is based upon the research question: Do homes built to a newer energy code deliver measurable energy savings compared to homes built to a much earlier energy code? This residential research study was focused on comparing …

Simulating The Energy Performance Of A Foam Roof System, Florida Solar Energy Center, Jeffrey Sonne

FSEC Energy Research Center®

Annual residential simulations were run in 13 US cities to determine the energy savings of using an insulated foam tile roof in retrofit applications where ceiling insulation was only R-11 or R-19. Variations included leaving the attic vented and sealing the attic space.

Sunsense/Sunsmart Plus-Up Schools Program Final Inspection Report, Florida Solar Energy Center, Susan Schleith

FSEC Energy Research Center®

This report provides information regarding the photovoltaic systems that are associated with the 2014 Sunsense/Sunsmart School Plus-UP program. Dave Click led the project as Principal Investigator and technical expert. Susan Schleith, participated as Co-Principal Investigator and education/school liaison. Four schools participated in the program. Each of the photovoltaic systems installed at the schools was inspected by the University of Central Florida's Florida Solar Energy Center (FSEC), as well as the local authority having jurisdiction (AHJ). This report details the results of the final inspections associated with National Electric Code (NEC) and performance testing as required by the Sunsense/Sunsmart Schools Plus-UP …

Investigation Of The Effectiveness And Failure Rates Of Whole-House Mechanical Ventilation Systems In Florida, Florida Solar Energy Center, Jeffrey Sonne

FSEC Energy Research Center®

This report presents the results of a field investigation of the effectiveness and failure rates of whole-house mechanical ventilation systems installed in Florida homes over the last 15 years. The report includes homeowner survey and ventilation system testing results and code modification recommendations based on study findings.

Cooling And Heating Season Impacts Of Right-Sizing Of Fixed- And Variable-Capacity Heat Pumps With Attic And Indoor Ductwork, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

The U.S. Department of Energy's research team Building America Partnership for Advanced Residential Construction implemented two phases of experiments to examine the cooling and heating seasonal and peak demand performance of a variable-capacity 2-ton SEER 22 heat pump versus a 3-ton variable-capacity SEER 21 heat pump with attic ducts and indoor ducts. The experiments also compared the cooling and heating seasonal and peak demand performance of 2-ton versus 3-ton fixed-capacity SEER 13 heat pumps with attic ducts and indoor ducts.

Developing Exhaust Air Energy Recovery Credits For The Florida Energy Code, Florida Solar Energy Center, Bereket Nigusse

FSEC Energy Research Center®

Energy Recovery Ventilator (ERV) or Heat Recovery Ventilator (HRV) devices recover energy from building's exhaust air to precondition outdoor air. Energy savings of ERV/HRV devices were determined for various commercial buildings in Florida climate using whole building energy simulation tool. The annual HVAC energy percent savings due to ERV/HRV device were calculated from HVAC energy use of a standard reference building without and with ERV/HRV device using EnergyPlus. The annual HVAC energy savings potential (ERV Credits) will be used for code compliance calculation when a compliance software does not have ERV modeling capability. The ERV/HRV credits were reported by building …

Maximum Energy Efficiency Cost Effectiveness In New Home Construction, Florida Solar Energy Center, Philip W. Fairey

FSEC Energy Research Center®

EnergyGauge® USA (v.4.0.00) is used to examine the cost effectiveness of high performance homes that are improved to significantly exceed the minimum requirements of the 2015 IECC. The objective of the study is to determine the maximum level of energy efficiency that can be considered cost effective to the consumer. For these purposes, it is the cost effectiveness of the entire package of measures that is considered by the analysis rather than the cost effectiveness of individual measures. Optimization and rank ordering of the individual improvement measures in the package is not considered by the analysis.

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