Aerospace Engineering Commons^™

Enabling Premixed Hydrogen-Air Combustion For Aeroengines Via Laboratory Experiment Modeling, Christopher James Caulfield

Masters Theses

All combustion systems from large scale power plants to the engines of cars to gas turbines in aircraft are looking for new fuel sources. Recently, clean energy for aviation has come into the foreground as an important issue due to the environment impacts of current combustion methods and fuels used. The aircraft industry is looking towards hydrogen as a new, powerful, and clean fuel of the future. However there are several engineering and scientific challenges to overcome before hydrogen can be deployed into the industry. These issues
range from storing the hydrogen in a viable cryogenic form for an aircraft …

Dynamic Maneuvers For Satellite On-Orbit Servicing Utilizing Novel Continuum Robotics: Development & Experimentation, Nathan Dalton

Masters Theses

Robotic on-orbit servicing is a developing technology that seeks to increase the longevity and repairability of faulty or aging resident space objects. In this research, the development of a flexible continuum manipulator for a small satellite system that performs low-complexity on-orbit servicing or debris removal is presented. Derivations of manipulator kinematics are described in detail, a non-linear control scheme has been developed, and the accuracy and servicing applications for the prototype are evaluated and discussed. The manipulator has been tested on an air-bearing dynamics simulator, and the results are extensively analyzed. System recommendations and future work suggestions are presented.

Dynamic Monitoring And Life Prediction Of Internal Strain-Gage Balances, David Leon Yoder

Masters Theses

Wind tunnel test customers continue to push the limits by producing air vehicle designs that produce high aerodynamic loads at the desired test conditions. These loads are a combination of steady aerodynamic, unsteady aerodynamic, and inertial forces. A methodology to monitor the health of a wind tunnel strain-gage balance has been developed. The objective of this methodology is to define the stress limits of the balance and monitor these limits so the balance can be safely tested without failure of the balance. A balance failure could result in costly damage to the wind tunnel model, support system, and the wind …

Optimization Of Titanium Liquid/Gas Diffusion Layers In Proton Exchange Membrane Electrolyzer Cells, Stuart Mccoy Steen

Masters Theses

Polymer electrolyte membrane electrolyzer cells (PEMECs), which are reverse PEM fuel cells (PEMFCs), are effective energy storage medium by producing hydrogen/oxygen from water using electricity from renewable energy sources. This is due in part because of its efficiency, high energy density, compact design, and large capacity. In a PEMEC, a liquid/gas diffusion layer (LGDL) is located between the catalyst layer and the current distributing flow field. The LGDL is expected to transport electrons, heat, and reactants/products to and from the catalyst layer with minimum voltage, current, thermal, interfacial, and fluidic losses. Carbon materials (carbon paper or carbon cloth), typically used …

Adomian Decomposition Of The Flowfield In A Simulated Rocket Motor, Jeisson Juliany Parra

Masters Theses

The work presents an analytic, approximate solution to an internal flowfield for a solid rocket motor. The flowfield is modeled as a wall-normal injection or suction in a symmetric porous channel with laterally expanding or contracting walls. From the effective speeds that gases are ejected into the combustion chamber of typical rocket motors, the flowfield is modeled to be incompressible. Since the flame zone occurs in a very thin space above the propellant grain surface, it will be disregarded. Assuming linearly varying axial velocity and uniform expansion (or contraction), the Navier-Stokes equations will be reduced into a single nonlinear equation …

An Interoperable Executive Library For Loosely Coupled Physics Systems, Andrew Austin Kail

Masters Theses

The complexity of simulating any system-wide process involving biomedical processes or thermal-fluid systems goes beyond the reach of a single computer code. In this document I present an Interoperable Executive Library (IEL) that has been designed to run, in parallel, a collection of multi-component physics simulations. The IEL is a light-weight integrator responsible for managing the distribution of data and memory, coordinating communication among parallel processes, and direct execution of a set of loosely coupled numerical and physics tasks HPC resources

Presented are two case studies utilizing the IEL. The first case simulates conjugate heat transfer coupled with a potential …

Heat Transfer Analysis Via Rate Based Sensors, Jake Erik Plewa

Masters Theses

This work presents an integrated rate-based sensor and method for resolving the surface heat flux of a fundamental inverse heat conduction problem without numerical regularization or differentiation in a semi-infinite geometry that additionally accounts for thermocouple delay due to its intrinsic time constant. The sensor uses well-designed analog filters to directly regularize raw voltage data to eliminate the need for numerical regularization methods. The sensor can also be used in a series of well-designed voltage-rate interfaces that directly measure the voltages from in-depth thermocouples, which are used in conjunction with the thermocouple calibration curve to provide higher-time derivatives of the …

Simulating The Effects Of Outer-Mold-Line Modification On The University Of Tennessee Space Institute's Aviation Systems' Piper Navajo Research Aircraft, Jonathan Vincent Kolwyck

Masters Theses

Aircraft used as research platforms often have their Outer-Mold-Lines (OML) modified to accommodate instrumentation packages associated with the research being performed. The external modification will change the aerodynamics of the aircraft, thus altering how the aircraft flies. The resulting performance, stability, and control of the aircraft can be effectively determined, but pilot opinion of aircraft handling qualities are largely unknown. The objective of this project is to be able to simulate aircraft flight control systems in the UTSI simulator, thus enabling the evaluation of pilot opinion of handling qualities. The design and implementation of a control loading system is described, …

Fault Diagnosis Via Univariate Frequency Analysis Monitoring: A Novel Technique Applied To A Simulated Integrated Drive Generator, Brian Keith Bailey

Masters Theses

The purpose of this research was to develop a fault detection and diagnostic method that would be able to detect and isolate seeded faults in data that was generated from a simulated integrated drive generator. The approach to the solution for this problem is summarized below.

A novel approach for the detection and diagnoses of an anomaly due the occurrence of a fault within a system has been developed. This innovative technique uses specific characteristics of the frequency spectrum of a univariate signal to monitor system health for abnormal behavior due to previously characterized component failure.

A fault detection and …

Droplet Characterization In The Wake Of Steam Turbine Cascades, Adam Charles Plondke

Masters Theses

In low-pressure steam turbines, water droplet formation on the surfaces of stationary stator blades can lead to erosion on downstream turbine blades and other equipment. One property that affects the size of the droplets that are formed is the adhesive forces between the water and the surface of the stator blade. The adhesive forces hold the droplets to the surface where they may combine, forming increasingly larger droplets. Eventually, the aerodynamic forces will tear the droplets off the surface, carrying them downstream.

To study the effect of stator surface properties on the droplet size distribution, four cascades of stator blades …

U.S Inflight Icing Accidents And Incidents, 2006 To 2010., Philip Appiah-Kubi

Masters Theses

Through its recommendations, the National Transportation Safety Board (NTSB) has helped the Federal Aviation Administration (FAA) introduce regulations that have helped to curtail icing accidents1 (an occurrence associated with the operation of an aircraft where as a result of the operation of an aircraft, any person receives fatal or serious injury or any aircraft receives substantial damage) and incidents1 (an occurrence, other than an accident, associated with the operation of an aircraft that affects or could affect the safety of operations). However, "the only acceptable safety goal of zero accident," proposed by former Secretary of Transportation, Federico Fabian Pena, has …

Introducing Water Vapor Into A High Vacuum Chamber At Aedc., James Philip Rogers

Masters Theses

A powdered form of calcium sulfate dihydrate (CaSO₄2H₂O) was heated to provide water vapor in a vacuum chamber for an experiment seeking to study cryodeposit thin films of ice at the Arnold Engineering Development Center (AEDC) in Tullahoma, TN. However, after the test was conducted, calcium sulfate deposits were found on all surfaces inside the vacuum chamber. It became clear that a new procedure for introducing the water vapor into the vacuum chamber needed to be developed. Calcium sulfate dihydrate, cobalt(II) chloride hexahydrate and 3 angstrom zeolite molecular sieves were investigated to determine how they could …

Aeolian Simulations: A Comparison Of Numerical And Experimental Results, With Projections For Titan., Oscar Lee Mathews

Masters Theses

Aeolian processes are major determinants of geomorphology on bodies in the Solar System possessing an atmosphere-surface interface and transportable sediment, including Earth, Mars, Venus, and Titan. Substantial efforts have been made over the last few decades to understand these processes using specialized wind tunnels, field studies, and, more recently, numerical simulations. This thesis describes a model of aeolian sediment transport using computational fluid dynamics (CFD), and compares the results with those obtained in the Martian Surface Wind Tunnel (MARSWIT) testing conducted in the Planetary Aeolian Laboratory at NASA Ames Research Center. The ultimate goal of the thesis was to develop …

A Feasibility Study For Using Commercial Off The Shelf (Cots) Hardware For Meeting Nasa’S Need For A Commercial Orbital Transportation Services (Cots) To The International Space Station - [Cots]2, Chad Lee Davis

Masters Theses

The space vehicle system concept (i.e. resupply vehicle) described is based on the new direction that President George W. Bush announced on January 14, 2004 for NASA’s Human Exploration, which has the space shuttle retiring in 2011 following the completion of the International Space Station (ISS). This leads to a problem for the ISS community regarding the capability of meeting a sixty metric-ton cargo shortfall in resupply and the ability of returning large payloads, experiment racks and any other items too large to fit into a crew only type spacecraft like the Orion or Soyuz. NASA and the ISS partners …

Automating The Data Reduction Process For More Efficient Flight Tests And Reducing The Time From Days To Hours, Joseph Kenneth Young

Masters Theses

The University of Tennessee Space Institute’s (UTSI) active airborne science program often requires extensive modification to its fleet of aircraft in order to meet mission and customer requirements. These modifications can alter the flight characteristics of the aircraft. In order to determine if the aircraft is safe to fly after modification and to find any new flight characteristics resulting from the modifications, the flight test engineer (FTE) must plan and conduct limited flight testing on the aircraft and evaluate the resulting data to ensure safety of flight. The more efficient the data reduction and analysis process the quicker the aircraft …

Propagation Of Periodic Waves Using Wave Confinement, Paula Cysneiros Sanematsu

Masters Theses

This thesis studies the behavior of the Eulerian scheme, with "Wave Confinement" (WC), when propagating periodic waves. WC is a recently developed method that was derived from the scheme "vorticity confinement" used in fluid mechanics, and it efficiently solves the linear wave equation. This new method is applicable for numerous simulations such as radio wave propagation, target detection, cell phone and satellite communications.

The WC scheme adds a nonlinear term to the discrete wave equation that adds stability with negative and positive diffusion, conserves integral quantities such as total amplitude and wave speed, and it allows wave propagation over long …

The Results Of The T-45 Main Landing Gear Uplock Investigation And The Effect That Organization Structure Had On Them, Christina Marie Stack

Masters Theses

The T-45, a military jet trainer aircraft for the Navy, recently experienced two cases of an uncommanded main landing gear extension during high airspeed and high g conditions. These events resulted in an investigation to understand the cause. The initial response to the mishaps was to limit the fleet to lower airspeeds since both mishaps occurred at high speeds. This limitation was not extensively restrictive for fleet operations; however, it was limiting for acceptance flights and functional check flights of aircraft. During the investigations, two different mechanical problems were discovered in the main landing gear uplock mechanism. This mechanism is …

Use Of Commercial Off The Shelf Gps Technology To Solve Guidance Problems With The Improved Tactical Air Launched Decoy (Itald), Scott Kenneth Toppel

Masters Theses

As the capabilities of threat surface-to-air missile systems increased, the US Navy looked to improve upon the performance of the Tactical Air Launched Decoy (TALD), an air launched glider vehicle with switchblade wings designed to resemble attacking aircraft to confuse and saturate enemy air defenses. In the early 1990’s the contractor proposed the Improved Tactical Air Launched Decoy (ITALD), a turbo jet powered air-launched vehicle which tripled the existing range and added a radar altimeter to simulate low level attacks.

In 1998, after several design iterations, the Naval Air Warfare Center at Point Mugu tested the ITALD for suitability in …

H-53e Super Stallion/Sea Dragon Auxiliary Power Plant Power Survey, Patrick Joseph Twomey

Masters Theses

This research has provided possible explanations to failures experienced in the P-7-2 Auxiliary Power Plant reduction gearbox as installed on the CH-53E Super Stallion and MH-53E Sea Dragon helicopters. Ground testing with the rotors static was conducted during two separate phases from March 1995 to December 1995. Reduction gearbox loading was measured, resulting in the identification of several detrimental over and transient loads. Loading reduction techniques are investigated, discussed, and/or evaluated for U.S. Navy and U.S. Marine Corps fleet introduction viability.