Aerospace Engineering Commons^™

Investigation Of Pitching And Plunging Motions On A Tandem Wing Configuration, Riley M. Capiro

Honors Undergraduate Theses

From the beginning of the history of flight, inspiration has been drawn from nature. Evolution has spent millions of years optimizing creatures that rely on flight as their means of locomotion. Today, aerial vehicles are very different to those from the time of the Wright brothers. One kind of vehicle that stands to benefit in mimicking nature is the drone, particularly smaller drones. Commonly used today by militaries, industry and civilians, drones are increasingly affordable while also decreasing in size thanks to advancements in electronics and manufacturing methods. The purpose of this thesis is to investigate how pitching and rolling …

The Early Propagation And Burning Of Hydrogen In The Process Of The Deflagration To Detonation Transition, Rom Amasay

Honors Undergraduate Theses

The safe and efficient propagation of the Deflagration to Detonation Transition (DDT) is a topic that has been researched for many years due to its applications in Aerospace and Mechanical Engineering. DDT is when fire caused by the burning of fuel is accelerated to the upper CJ point on the Rankine Hugoniot curve due to instabilities in the flame and the turbulence caused by these instabilities. The complex flame dynamics that go along with DDT have ensured that the process is yet to be fully understood and defined. This research will work towards observing the early stages of burning hydrogen-air …

Atomization Of A Liquid Water Jet In Crossflow At Varying Hot Temperatures For High-Speed Engine And Stratospheric Aerosol Injection Applications, Luke Caetano

Honors Undergraduate Theses

This paper aims to study how varying crossflow burning temperatures from 1100 C to 1800 C affect the liquid droplet breakup, size distribution, and atomization of a liquid water jet injected into a vitiated crossflow. The LJIC injection mechanism was implemented using the high-pressure axially staged combustion facility at the University of Central Florida. The measurement devices used to gather particle data from the exhaust plume were the TSI Aerodynamic Particle Sizer (APS), which measures particles between 0.523 µm and 20 µm, and the Sensirion SPS30 (SPS30), which measures particles between 0.3 µm and 10 µm. Both measurement devices were …

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, 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, 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. …

Studying The Electrostatic Effects On The Dynamics Of Charged Lunar Dust Via Discrete Element Method, Hao Wang

Electronic Theses and Dissertations, 2020-2023

Dust problems raise significant concerns in planetary surface exploration. The unusual behavior of the dust particles that surround the vehicle after engine cutoff has the potential to have more of an influence on surface systems than the high velocity lunar rocket plume ejecta in the landing process. A prevailing hypothesis attributes the levitation and transport of dust particles on the surface of airless bodies to the electrostatic effects and electric field. However, there is no accurate model considering the inter-particle electrostatic interactions, especially when the particles are charged by plume. This dissertation aims to understand the behavior of charged lunar …

Exploration Of Shock-Droplet Ignition And Combustion, John Patten

Electronic Theses and Dissertations, 2020-2023

Liquid fuels are desirable in aerospace applications due to their higher energy density when compared to gaseous fuels. With the advent of detonation-based engines, it is necessary to characterize and analyze how liquid fuel interacts with detonation waves as well as shocks to ignite. While liquid fuel sprays have been proven to successfully aid and sustain detonations, the physical mechanism by which the individual liquid droplets accomplish this is yet to be understood. Such knowledge allows for more predictable detonation properties, which in turn can let detonation-based engines be sustained more easily. This research seeks to quantify and characterize interactions …

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 …

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, 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 …

Aerodynamic Characterization Of An Elliptical Fairing In The Wake Of A Bluff Body, Luis Amaya

Electronic Theses and Dissertations, 2020-2023

Aerodynamic optimization is a key step in designing planes, cars, and even buildings. Numerical modeling is used to automate the optimization process and can use different methods to iterate through designs. In this process, consideration of the starting design is paramount as a poor choice can use up computational time and effort. Often, these designs are made with the intention of being out in the open, for which studies on shape variations in freestream situations abound. However, for the case where an object must be placed in the wake of another, there is little research. The study presented here aims …

Investigation Into Wedge Turbulator Effects In High Aspect Ratio Cooling Channels, Daniel Garcia

Electronic Theses and Dissertations, 2020-2023

With reusability being a novel design parameter for liquid rocket engines (LRE), the need to lower internal wall temperatures for an increased engine longevity is a desired outcome. One of the mechanisms that has been effectively implemented is the use of high aspect ratio cooling channels (HARCC) to promote fin-like effects from internal cooling channel sidewalls. In the gas turbine industry, the use of wedge turbulators has gained recognition for its heat augmentation properties with relatively low pressure drop penalty. In an ideal case, LRE's could adopt the wedge turbulator cooling technique to enhance the benefits of HARCC with minimal …

On Mode Transition Phenomenon And Operating Conditions In Rotating Detonation Rocket Engines, Taha Rezzag-Lebza

Electronic Theses and Dissertations, 2020-2023

The work presented herein consist of first studying the instantaneous properties of the detonation waves in a rotating detonation rocket engine by tracking each individual wave and recording its position, velocity, and peak intensity as it travels around the annulus. Results for a steady portion of a test performed on a rotating detonation rocket engine show that the wave properties exhibit oscillatory behavior. Results obtained from the rotating detonation rocket engine show that the properties are highly dependent on the azimuthal position. In an attempt to understanding the cause of such a behavior, similar investigations were performed on an air-breathing …

Creasing Of Polyimide Thin Film For Use In Solar Sails, Andrew Allen

Electronic Theses and Dissertations, 2020-2023

Polymer thin membranes are used in a variety of deployable structures that require large areas and compact stowage. Packaging membrane structures often involves creasing the membrane along predefined fold lines to enforce the desired kinematics under folding action. Inducing permanent deformation by folding to a high curvature is a common method to create creases, particularly in the design of solar sails. The distinct mechanical characteristics at the crease regions have a profound effect on the subsequent deployment and tensioning of the membrane structures. The mechanical and geometric properties at the crease are related to the crease formation process, but the …

Molten Regolith Electrolysis Processing For Lunar Isru: Financial And Physics Analysis Of Spacex Starship Transportation, Cheyenne Harper

Honors Undergraduate Theses

The purpose of the following research is to explore molten regolith electrolysis (MRE) methodology for in-situ resource utilization (ISRU) of Highlands lunar regolith, to be explored during the initial Artemis missions. An analysis of potential commercial launch providers for MRE-equipment based on technology-readiness level (TRL), payload mass support, and $ USD/kg payload price is provided. SpaceX is ultimately proposed as a launch provider of MRE equipment following multi-factorial analysis, with the SpaceX Starship human landing system (HLS) variant proposed for supporting MRE payload. Finally, customers of regolith-derived oxygen, aluminum, and silicon are distinguished to form the business case for operating …

A Finite Difference Model For Induced Hypothermia During Shock, Dylan S. Lyon

Honors Undergraduate Theses

The modified Fiala model from Westin was implemented with conditions for circulatory shock and hypothermia. The purpose is to model Emergency Preservation and Resuscitation (EPR), a procedure for inducing hypothermia in patients. Cold tissue temperatures reduce metabolism exponentially, greatly extending the window of anaerobic metabolic activity before permanent deoxygenation damage. EPR in patients undergoing hypovolemic shock can preserve the patient until primary surgical care and blood transfusions are attainable., thereby increasing survival rates. The main applications of EPR are military in-situ stabilization for transit to clinical care and extending the survivability of patients requiring prolonged surgery before blood transfusion. The …

Computational Studies For Extending Understanding Of Complex Droplet Breakup Mechanisms, Caroline Anderson

Electronic Theses and Dissertations, 2020-2023

Conventional methods of classifying droplet breakup are evaluated in the context of unique variation in environmental and droplet fluid conditions. Most characterization is developed for subsonic speeds and Newtonian fluids, so this study extends understanding on how these forms change to a span of applications outside these conditions. Presented examples include the impact effects on hypersonic vehicles travelling through precipitation, where even smallest of rain drops at such speeds can cause damage. Before the droplet even reaches the vehicle, it interacts with the detached bow shock that leads it. Another example of exceptional recent concern is risk of viral transmission …

Simulating Ejecta Blown Off The Lunar Surface Due To Landing Spacecraft Using The Mercury N-Body Integrator, Isabel Rivera

Electronic Theses and Dissertations, 2020-2023

The experiences of the Apollo lunar landings revealed the danger lunar dust can pose to surrounding hardware, outposts, and orbiting spacecraft. Future lunar missions such as the Artemis program will require more information about the trajectories of ejecta blown by landers to protect orbiting spacecraft such as the Lunar Gateway. In this paper, we simulate lunar lander ejecta trajectories using the Mercury N-body integrator. We placed cones of test particles on the Moon at the North Pole, South Pole, and Equator with various ejection speeds and angles. The results show that particles ejected at speeds near the Moon's escape velocity …

Experimental Study Of A Liquid Fuel Bluff Body Flame At Elevated Pressures, Karam Paul

Honors Undergraduate Theses

The purpose of this research was to operate a bluff body flame holder with the objective of stabilizing a flame at elevated pressures over a range of equivalence ratios. The ability to have a ground-based test rig capable of maintaining stable flames at high pressures and temperatures is critical in understanding flames present in modern jet engines and gas turbine technologies. The facility was reconfigured multiple times and the resultant flame was imaged within the optical test section. A converging nozzle was utilized to choke the flow and vary the operating pressures up to 5 atm. By regulating mass flow …

Motor Control System For Near-Resonance High-Cycle Fatigue Testing, Samer K. Armaly

Honors Undergraduate Theses

This research project develops a low-cost high-cycle fatigue (HCF) testing system comprised of an AC motor, variable frequency drive (VFD), eccentric cam, and feedback controller. The system acts as a forced harmonic oscillator leveraging mechanical resonance to vibrate a specimen at a frequency required to induce the testing's strain amplitudes.

This system depends highly on the material being tested. As such, the controller incorporates material characteristics. A frequency sweep measures the strain amplitude to characterize the specimen. Additionally, other measurements such as acceleration can be used as a proxy control variables for strain. A function converts the control variable to …

Optimization Of A Wing Supporting A Coaxial Rotor For Multiple Flight Conditions, Tadd Yeager

Electronic Theses and Dissertations, 2020-2023

Rotor-powered drones continue to grow in popularity in private and government sectors. The use of these drones in challenging environments and in high stakes applications calls for a certain level of robustness and redundancy. Often, these drones are equipped with sets of paired coaxial rotors, which not only improve the performance of the vehicle, but also ensure that a failure of one motor does not constitute the failure of the whole vehicle. Some applications such as extraterrestrial exploration, which use these coaxial rotors, can benefit from a wing shaped rotor arm to reduce drag and increase lift, extending mission lifetime. …

Development Of Multi-Scale Characterization Techniques For Stress Corrosion Cracking Of Aerospace Alloys, Nicholas Reed

Electronic Theses and Dissertations, 2020-2023

Corrosion presents an inherent challenge in the safe and effective use of metallic aerospace structures for extended periods of time. Progress in the fundamental understanding of corrosion initiation and propagation under stress requires a multi-scale approach that leverages experiments to develop predictive models. Although there exists a large amount of research results tracking the corrosive processes of anodic dissolution and hydrogen embrittlement, the amount of available data and modeling of the micro-scale initiation of corrosion is sparse. This work leverages a suite of characterization techniques to systematically analyze an aerospace grade aluminum alloy AA7075-T6, providing important multi-scale data for correlation …

Bicycle Wheel Aerodynamics Predictions Using Cfd: Efficiency Using Blade Element Method, Drew Vigne

Honors Undergraduate Theses

The cycling industry has long relied on expensive wind tunnel testing when designing aerodynamic products, particularly in the context of wheels which account for 10 to 15 percent of a cyclist's total aerodynamic drag. With the recent advent of Computational Fluid Dynamics (CFD), the industry now has an economical tool to supplement the wheel design process; however, the complex nature of rotating spoked wheels requires high resolution meshes to model at acceptable fidelity. This research investigates an alternative CFD method that lowers the computational cost of modeling aerodynamic bicycle wheels by modeling spokes using Blade Element Method (BEM). Two CFD …

Development Of Lifting Line Theory For The Fanwing Propulsion System, Christopher Kaminski

Honors Undergraduate Theses

The FanWing propulsion system is a novel propulsion system which aerodynamically behaves as a hybrid between a helicopter and a fixed wing aircraft, and if the knowledge base with regards to this novel concept can be fully explored, there could be a new class of aircraft developed. In the current research, only 2D CFD studies have been done for the FanWing, hence the 3D lift characteristics of the FanWing have been unknown thus far, at least in the theoretical domain. Therefore, it was proposed to develop a modified Prandtl's Lifting Line Theory numerical solution and a CFD solution, comparing the …

Numerical Modeling Of Shockwave Initiated Combustion Of A Hydrogen-Oxygen Mixture Within A Shock Tube, Reed Forehand

Electronic Theses and Dissertations, 2020-2023

Shock tubes are as close to an ideal reactor as most modern experiments can attain to examine chemical kinetics. As reaction temperatures drop, homogeneous combustion within a shock tube begins to exhibit inhomogeneous modes, which in a typical Hydrogen-Oxygen system are ex- pressed as deflagration to detonation transition. Experimental results of such a system in the Uni- versity of Central Florida's low-pressure shock tube have been collected through end and side-wall imaging to analyze flame structure and chemical kinetics. The purpose of this work is to con- duct a baselining of these results using both chemical and computational fluid dynamics …

Solid Materia And Multiphase Detonations Wave Dynamics In A Rotating Detonation Engine, Ian Dunn

Electronic Theses and Dissertations, 2020-2023

Coal dust explosions can be hazardous; however, they can also generate a significant rise in stagnation pressure if adequately harnessed. Rotating detonation engine combustors seek to take advantage of the stagnation pressure rise phenomenon in a more sustained and controlled manner via confinement to a physical annulus, leading to increased overall thermodynamic efficiency. This investigation presents an analysis of detonations fueled by Carbon Black, a solid particulate consisting of virtually pure carbon molecules and lean Hydrogen-Air mixtures. As was previously realized with the addition of Carbon Black, an increase of operability limits and detonation velocities over that of a pure …

Mimicking Blood Rheology For More Accurate Modeling In Benchtop Research, Lindsey Webb

The Pegasus Review: UCF Undergraduate Research Journal

Because blood is challenging to use as a working fluid in a laboratory setting due to health and safety concerns, a blood analogue would be useful to perform benchtop experiments. Viscosity is an important fluid property for modeling and experiments, especially because blood is a shear thinning fluid; therefore, it has a decreasing viscosity with higher shear rates. This project seeks to create a blood-mimicking fluid for benchtop laboratory use. Numerous fluids with different combinations of water, glycerin, salt, and xanthan gum (XG) were created to mimic blood viscosity at different hematocrit levels. Four additional solutions were also created from …

A Generalized Low Order Model For Vortex Shedding From A Tandem Cylinder Arrangement Using Delay Coupled Van Der Pol Oscillators, Michael Soroka

Honors Undergraduate Theses

A generalized low order model (LOM) for the fluctuating lift coefficient caused by vortex shedding from a tandem cylinder pair is proposed to expand upon models from previous authors. This model could provide a reduced computational time method for collecting qualitative and quantitive data from a tandem shedding pair. A delay coupled system with sufficient bifurcation characteristics is developed to account for the different flow regimes (extended-body, reattachment, and co-shedding) which occur as cylinder spacing is varied. Coefficient and parameter fitting is performed to fit experimental data. Finally, results and physical interpretations of the interactions in the model are discussed. …

Inertial Orbit Estimation Using Multiple Space Based Observers: A New Measurement Model, James Hippelheuser

Electronic Theses and Dissertations, 2020-2023

Presented within this work is a new method for inertial orbit estimation of an object, either known or unknown, adaptable to a network of low-cost observation satellites. The observation satellites would only require a monocular camera for line of sight measurements. Using the line of sight measurements of each observer, a pair of orthogonal geometric planes that intersect both the observation satellite and the target are created. The intersection of the two planes in the inertial frame defines the new measurement model that is implemented with multiple observation nodes. Total system observability is analyzed and the instantaneous (per node) observability …