Engineering Commons^™

The Design For Manufacturing And Assembly Analysis And Redesign Of An Aircraft Refueling Door Hinge Utilizing Additive Manufacturing, Kurt A. Schwarz

Doctoral Dissertations and Master's Theses

In this thesis, an aircraft door hinge assembly provided by Gulfstream Aerospace was analyzed following an established process called DFMA. The hinge was then redesigned to be additively manufactured, which is uncommon currently in industry for load bearing components. It was shown that the Design for Manufacturing (DFM) guidelines were inadequate when applied to the new technology of additive manufacturing (AM). This was primarily due to AM's unique and unprecedented manufacturing capabilities.

A conservative redesign approach was followed due to a limitation in current AM material properties and time available for analysis. Despite this, a significant improvement in weight reduction …

Scalloped Leading Edge Vaned Diffuser Analysis For A Compact High Pressure Ratio Centrifugal Compressor, Vinod Poonamchand Gehlot

Doctoral Dissertations and Master's Theses

Microturbines and small gas turbines are often an attractive option for turbo-hybryd application research in aviation due to their simple design and high power to weight ratio. However, the low operating pressure ratios of microturbines leads to low thermal efficiency, which results in very high fuel consumption. Higher operating pressure ratios in microturbines could vastly improve their current fuel efficiency. This thesis focuses on developing a compact, single stage 8:1 pressure ratio centrifugal compressor stage designed to meet the high-pressure ratio requirements of microturbines and small gas turbine engines in turbo hybrid-electric propulsion applications. The first stage vaned diffuser was …

Comparing Different Methods For Estimating Total Open Heliospheric Magnetic Flux, Samantha J. Wallace

Doctoral Dissertations and Master's Theses

There are extended periods over the solar cycle where significant discrepancies occur between the observed open magnetic flux (i.e., those based on spacecraft observations) and that determined from coronal models. One explanation for the source of these discrepancies is the magnetic fields in CMEs, which have yet to magnetically disconnect from the Sun. These “closed” flux sources can be included in open flux estimates, because open and closed magnetic field lines are not easily distinguished in spacecraft data. Another possibility is that a portion of the open flux measured by in situ spacecraft originates from the time-dependent evolution of solar …

Benchmarking Of Computational Models Against Experimental Data For Adiabatic Film-Cooling Effectiveness For Large Spacing Compound Angle Full Coverage Film Cooling Arrays, Simon R. Martinez

Doctoral Dissertations and Master's Theses

This study aims to benchmark experimental data that tested the effects of blowing ratio, surface angle, and hole spacing for two full coverage geometries composed of cylindrical staggered holes at a compound angle of 45 degrees. These holes varied parametrically the inclination angle to be 30 and 45 degrees, while maintaining a lateral and axial spacing of 14.5 hole diameters. Within this study, the local film cooling effectiveness was obtained from 30 rows for the 14.5 diameter spacing. Utilizing a velocity profile at the crossflow inlet produced significant differences in the results produced when compared to a uniform freestream velocity …

Investigation Of Pulse Detonation Engines: The Effect Of Variable Blockage Ratio On The Deflagration To Detonation Transition, Christopher Tate

Doctoral Dissertations and Master's Theses

Detonation and constant volume combustion is well known to be thermodynamically more efficient than the typically utilized constant pressure. There have been numerous approaches of achieving detonation through deflagration-to-detonation transition most of which use evenly spaced obstacles with a specified constant blockage ratio to generate turbulence and pressure fluctuations. There have been few efforts to study effects of varying blockage ratio as a function of axial distance. This research analyzes the effect of variable blockage ratio on deflagration-to-detonation transition in ethylene-air mixtures. The experiments show that with certain blockage ratio functions detonation is more repeatable and produces a smaller variation …

Analysis Of A Hybrid Rocket Burn Using Generalized Compressible Flow, Naveen Sri Uddanti

Doctoral Dissertations and Master's Theses

The analysis of square ports in a hybrid rocket is simple when compared to other complicated port geometries such as a wagon wheel configuration. In the present work, fuel grains with several ports in a hybrid rocket engine are analyzed by transforming the ports into equivalent square ports. As an example, the internal ballistics of a hybrid rocket with circular ports is analyzed by transforming it to an equivalent solid grain with square ports having the same amount of solid fuel and burn time. The results obtained are similar to that of circular port but with a slight decrease in …

Numerical Investigation Of Tonal Noise On A Transitional Airfoil Under Varying Conditions, Warren W. Hiner

Doctoral Dissertations and Master's Theses

The generation of discrete acoustic tones is a problem of interest in transitional airfoils. Such tones exist for moderate Re below 2,000,000 and for low to moderate angles of attack. The purpose of this study is to use linear stability theory to study the growth of instabilities on the pressure and suction surfaces of airfoils for varying Re between 144,000 and 468,000 and angles of attack between 0˚ and 12˚. High accuracy 2D simulations based on an Implicit Large Eddy Simulation (ILES) code are conducted for a NACA0012 airfoil for varied conditions, and linear stability analysis is performed to predict …

Determination Of A Simplified High-Order Vortex Equation For Radial Equilibrium With Cfd Verification, Travis K. Matsumoto

Doctoral Dissertations and Master's Theses

The goal of this thesis is to determine a flow model that provides a better blade design over current design techniques utilizing a hybrid vortex model. This hybrid vortex model combines the well-established simple radial equilibrium vortex models into a higher order equation that will establish the basis for a more flow-accurate model. In this paper, we will discuss the basis and derivation of these vortex models, the shortcomings of current techniques, and verification of the new vortex model with empirical data via Computational Fluid Dynamic (CFD). The simple radial equilibrium equation set has been known to the scientific community …

Hybrid Electric Power System Validation Through Parameter Optimization, Hasnaa Khalifi

Doctoral Dissertations and Master's Theses

Battery models can be developed from first principles or from empirical methods. The work presented in this thesis is semi-empirical, the model was validated using test data through parameter optimization. Simulink Parameter Estimation toolbox was used to identify the battery parameters and validate the battery model with test data. Experimental data was obtained by discharging the battery of a modified 2013 Chevrolet Malibu hybrid electric vehicle. The resulting battery model provided accurate simulation results over the validation data. For the constant current discharge, the mean squared error between measured and simulated data was 0.26 volts for the terminal voltage and …

Aircraft De-Icing System Using Thermal Conductive Fibers, Min Soon Park

Doctoral Dissertations and Master's Theses

The accumulation of ice on the leading edges of aircraft wing poses complications for flight control as drag is increased with a tendency for higher relative turbulence over the wing. Pre-emptive and reactive ice removal techniques have been employed in the past by electromechanical, thermal, chemical and pneumatic methods. In this thesis, a carbon fiber fabric is utilized as a heating de-icer for composites aircraft wing surface structures. Two prototypes are constructed, tested to generate temperature profiles, and an appropriate heating voltage is selected for effective de-icing via distinct avenues of heating system configurations. The heat transfer efficiency of the …

Economic Interrelationships And Impacts Of The Aviation/Aerospace Industry In The State Of Florida Using Input-Output Analysis, Kelly A. Whealan-George

Doctoral Dissertations and Master's Theses

The study provided a detailed description of the interrelatedness of the aviation and aerospace industry with principal industries in Florida and Volusia County (VC) using Input-Output (IO) analysis. Additionally, this research provided an economic impact analysis of the creation of a university research park in Daytona Beach (DB). The economic impact measures included not only direct economic output and industry employment descriptions but also described the multiplier effects in the form of indirect and induced impacts using data for 2012.

This research concluded the average labor income of the aviation and aerospace industry was higher than average labor income in …

Cubesat Wakes In The Earth’S Ionosphere, Robert M. Albarran Ii

Doctoral Dissertations and Master's Theses

Space exploration is currently being revolutionized by the advent of the CubeSat: 10cm cubed satellites that typically deploy in constellations for less than $100,000. Spacecraft instrumentation design must be redefined to abide by the compact CubeSat payload. Furthermore, the CubeSat dimension must be considered with respect to characteristic length scales of the space plasma environment, namely, the Debye length. Although spacecraft-plasma interactions- surface charging, plasma sheaths and wakes- have been well-studied for larger satellites, they are less understood for CubeSats.

The Dynamic Ionosphere CubeSat Experiment (DICE) is a 1.5U CubeSat which recently ended its mission. DICE carried two fixed-bias Langmuir …