Aerospace Engineering Commons^™

Performance Testing Of Various Nozzle Design For Water Electrolysis Thruster, Yuen Liu

Theses and Dissertations

The purpose of this research is to develop new nozzles for the HYDROS^TM thruster, a pulsed chemical thruster, to improve the current flight performance. This research consists of a base line test of the factory nozzle, as well as testing of three 15-degree conical nozzles with different expansion ratios. Experiments were conducted at plenum pressures 30, 40, and 45 psia to ensure the thruster is throttleable. Impulse bit data was collected through measuring the impulse response of each firing using a torsional balance thrust stand. Analysis of the thruster performance included calculations of impulse bit, specific impulse, thrust coefficient, …

Fatigue Behavior Of An Advanced Sic/Sic Composite At 1300° C In Air And Steam, Michael D. Lee

Theses and Dissertations

The fatigue behavior of an advanced silicon carbide/silicon carbide (SiC/SiC) ceramic matrix composite (CMC) was investigated at 1300 ºC in laboratory air and in steam environments. The composite was manufactured using chemical vapor infiltration (CVI). The composite consisted of an oxidation-inhibited matrix, which was comprised of alternating layers of silicon carbide and boron carbide and was reinforced with laminated Hi-Nicalon™ fibers woven in a plain weave. Fiber preforms had pyrolytic carbon fiber coating with boron carbon overlay applied. Two specimen geometries were evaluated, a dog bone and an hourglass geometry. Tensile stress-strain behavior and tensile properties were evaluated at 1300 …

Military Applications Of High-Altitude Satellite Orbits In A Multi-Body Dynamical Environment Using Numerical Methods And Dynamical Systems Theory, Meredith M. Wilmer

Theses and Dissertations

The circular restricted three-body problem (CR3BP) is a simplified dynamical model for a satellite under the gravitational influence of both the Earth and the Moon, maintaining closer fidelity to the gravitational environment experienced by a high-altitude Earth-orbiting spacecraft than modeling in the Earth-satellite two-body problem. Resonant orbit arcs are used to determine an initial guess to input into an algorithm that computes a trajectory solution with specific design requirements and constraints. A test case uses this method to compute a lunar fly-by transfer solution requiring less than two-body transfer methods and offers an unusual pathway that adds an unpredictability element …

Creep Of Hi-Nicalon™ S Ceramic Fiber Tows At 700°C In Air And In Silicic Acid-Saturated Steam, Matthew W. Piper

Theses and Dissertations

Aircraft structural and engine components are subjected to elevated temperature and steam environments during operation. Turbine blades experience particularly harsh conditions that are approaching the operating temperature limits of current Nickel-based superalloys even with active cooling. Ceramic matrix composites (CMCs), which demonstrate high specific strength and specific stiffness and maintain these properties at elevated temperatures such that active cooling is not required, are prime candidates to replace superalloys as the materials for turbine blades. Ceramic matrix composites are composite materials that consist of a ceramic matrix with fiber reinforcement. This research investigated a silicon carbide (SiC) fiber, Hi-Nicalon™ S, which …

Liquid Fuel Film Cooling: A Cfd Analysis With Hydrocarbon Fuel, Jacob D. Bills

Theses and Dissertations

Cooling of liquid rocket engine combustion chambers and nozzles is a critical component to liquid rocket engine design. A common method of cooling is liquid fuel film cooling. Liquid fuel is injected along the surface of the wall to act as a barrier against the core combustion gases. A numerical model is developed for simulating liquid fuel _lm cooling in a rocket engine using a hydrocarbon fuel. The model incorporates turbulent multiphase ow with species transport within the commercial ANSYS® Fluent CFD software. Conjugate heat transfer is simulated through walls containing embedded cooling channels. A novel User Defined Function is …

Conceptual Design, Structural Analysis, And Design Space Exploration Of A Vacuum Lighter Than Air Vehicle, Brian C. Cranston

Theses and Dissertations

The research detailed in this study investigates an internal vacuum as well as its optimal structural design, utilizing currently available materials, as an alternative to traditional gases to create and sustain buoyancy in lighter than air vehicles. To date, the consideration of a vacuum lighter than air vehicle has been limited to three sources of literature, the earliest of which dates back to 1663. This study will initially summarize and review this literature. We will then combine finite element analysis, dimensional analysis, design of experiments, and response surface methodology studies to explore the feasibility, and the functional design of a …

Spectroscopic Measurement Of Gas Temperature In Small Internal Combustion Engines, Matthew J. Deutsch

Theses and Dissertations

The Small Engine Research Bench (SERB) was used previously to measure spatially and temporally averaged heat flux, as well as local, instantaneous heat flux at several external locations, for a series of small engines (1 - 10 kW). This investigation obtained time averaged crank angle resolved measurements of the in-cylinder gas temperature using Fourier transform infrared (FTIR) absorption thermometry. The results, coupled with heat flux measurements, will enable the validation or refinement of existing thermal energy loss models.

Effects Of Additive Manufacturing Methods On The Dynamic Properties Of 15-5ph Stainless Steel, Allison A. Dempsey

Theses and Dissertations

Experimental research was conducted to determine the dynamic properties and characterize the microstructure of 15-5PH Stainless Steel manufactured through Direct Metal Laser Sintering (DMLS) additive manufacturing (AM) processes and heat treated using common heat treatment protocols. A thorough understanding of the material's properties is necessary before such parts are utilized in an operational capacity. Of the five builds, two deviated significantly from the specified composition of 15-5PH stainless steel. The remaining three builds, possessing the desired composition and crystalline structure, were tested in compression and tension at two strain rates. Tension tests using a reflected wave and a momentum trap …

Surface Roughness Of Electron Beam Melting Ti-6al-4v Effect On Ultrasonic Testing, Evan T. Hanks

Theses and Dissertations

Experimental research was conducted on the effects of surface roughness on ultrasonic non-destructive testing of Electron Beam Melted (EBM) additively manufactured Ti-6Al-4V. Additive Manufacturing (AM) is a developing technology with many potential benefits, but certain challenges posed by its use require further research before AM parts are viable for widespread use in the aviation industry. Possible applications of this new technology include, Aircraft Battle Damage Repair (ABDR), small batch manufacturing to fill supply gaps, and replacement for obsolete parts. The research presented here assesses the effectiveness of ultrasonic inspection in detecting manufactured flaws in EBM manufactured Ti-6Al-4V. EBM products are …

Effectiveness Based Design Of A Tactical Tanker Aircraft, Andrew K. Petry

Theses and Dissertations

An approach to drive conceptual aircraft design using mission effectiveness parameters is described and applied to an operational scenario. The scenario includes traditional aircraft refueling tankers and a proposed tactical tanker concept supporting fighter aircraft conducting offensive (OCA) and defensive (DCA) counter air patrols. Traditional conceptual design methodologies were used to generate a baseline design for a tactical tanker aircraft, which was evaluated using a MATLAB-based model to investigate Measures of Effectiveness (MOE). The model holds the traditional tanker and fighter capabilities constant, while varying the tactical tanker's specific fuel consumption, lift-to-drag ratio, fuel payload, mass fraction, and proximity to …

Design And Flight Test Of A Weapons-Cavity Acoustics And Separation Test Bed, Zachary Probst

Theses and Dissertations

Two very important, and often detrimental, phenomena can occur when an open weapons bay, or more generally-a cavity, is exposed to high-velocity flow. First, a shear layer develops over the cavity, leading to large regions of difficult-to-predict flow. Second, dynamic pressure oscillations are generated within the cavity itself. These two issues can combine to have multiple harmful effects on weapons carriage and employment. This provided motivation for flight tests which quantify forces and moments on a store, mounted at various positions in the cavity, for a variety of flight conditions. Specifically, a low-cost, easily reconfigurable test bed for weapons-cavity research …

Influence Of Coolant Flow Rate Parameters In Scaling Gas Turbine Cooling Effectiveness, Connor J. Wiese

Theses and Dissertations

Film cooling scheme development for use in gas turbine engines often entails the characterization of adiabatic wall temperature distributions in order to determine the driving temperatures for the convective heat transfer processes in the engine. For convenience, adiabatic effectiveness experiments are often performed near room temperature and presumed to scale the engine condition. In order to perform these experiments, researchers elect to match the freestream Reynolds number to that of the engine. When scaling to engine temperatures, however, coolant and freestream fluid properties both change nonlinearly. Therefore the ratio of these properties does not remain constant as the temperature changes. …

Investigation Into Active Spanwise Camber Deformation On The Lateral Stability And Roll Control Of The X-56a Compared To Conventional Ailerons, Eric T. Yerly

Theses and Dissertations

"This research compares the stability and roll characteristics of an X-56A using AFRL’s Variable Camber Complaint wing technology to actively change wing camber compared to conventional ailerons deflected at set angles. An analysis of the stability and roll characteristics was modeled using a 3-D vortex lattice theory simulation, and that data was compared to wind tunnel testing to verify and validate the model results. Wind tunnel data was collected using 19 inch 3-D printed scale models with wings fabricated with a pre-determined percentage of camber deformation, as well as models with fixed aileron deflections. The full span model changed camber …

Force And Moment Measurements Applicable To A Flexible Weapons System, James B. Sellers

Theses and Dissertations

Continuing the development of the 6-DOF Motion Test Apparatus (MTA) for performing dynamic wind tunnel tests revealed the importance of a capable data acquisition (DAQ) system for collecting and analyzing data. Assembling and testing the DAQ system in conjunction with the MTA, AFIT Low-Speed Wind Tunnel, and a selection of high-performance sensors was the primary focus of this research. Specifically, acquiring time-accurate aerodynamic force and moment measurements on a variety of test models was of high importance. With the established real-time DAQ system hardware, a National Instruments (NI) LabVIEW program was created to acquire data from an ATI Nano25-E force …

Real-Time Implementation Of Vision-Aided Monocular Navigation For Small Fixed-Wing Unmanned Aerial Systems, Timothy I. Machin

Theses and Dissertations

The goal of this project was to develop and implement algorithms to demonstrate real-time positioning of a UAV using a monocular camera combined with previously collected orthorectified imagery. Unlike previous tests, this project did not utilize a full inertial navigation system (INS) for attitude, but instead had to rely on the attitude obtained by inexpensive commercial off-the-shelf (COTS) autopilots. The system consisted of primarily COTS components and open-source software, and was own over Camp Atterbury, IN for a sequence of flight tests in Fall 2015. The system obtained valid solutions over much of the flight path, identifying features in the …

Minimum-Fuel Trajectory Design In Multiple Dynamical Environments Utilizing Direct Transcription Methods And Particle Swarm Optimization, Alfredo G. Zurita Jr.

Theses and Dissertations

Particle swarm optimization is used to generate an initial guess for designing fuel-optimal trajectories in multiple dynamical environments. Trajectories designed in the vicinity of Earth use continuous or finite low-thrust burning and transfer from an inclined or equatorial circular low-Earth-orbit to a geostationary orbit. In addition, a trajectory from near-Earth to a periodic orbit about the cislunar Lagrange point with minimized impulsive burn costs is designed within a multi-body dynamical environment. Direct transcription is used in conjunction with a nonlinear optimizer to find locally-optimal trajectories given the initial guess. The near-Earth transfers are propagated at low-level thrust where neither the …

Pointing Analysis And Design Drivers For Low Earth Orbit Satellite Quantum Key Distribution, Jeremiah A. Specht

Theses and Dissertations

The world relies on encryption to perform critical and sensitive tasks every day. If quantum computing matures, the capability to decode keys and decrypt messages becomes possible. Quantum key distribution (QKD) is a method of distributing secure cryptographic keys which relies on the laws of quantum mechanics. Current implementations of QKD use fiber-based channels which limit the number of users and the distance between users. Satellite-based QKD using free-space channels is proposed as a feasible secure global communication solution. Since a free-space link does not use a waveguide, pointing a transmitter to receiver is required to ensure signal arrival. In …

Multi-Trajectory Automatic Ground Collision Avoidance System With Flight Tests (Project Have Escape), John V. Trombetta

Theses and Dissertations

Multi-trajectory automatic collision avoidance techniques for heavy-type aircraft are explored to increase aviation safety procedures and decrease losses due to controlled flight into terrain. Additionally, this research includes flight test results from the United States Test Pilot School’s Test Management Project (TMP) titled Have Emergency Safe Calculated Autonomous Preplanned Exit (ESCAPE). Currently, the heavy aircraft community lacks an automatic collision avoidance system that has proven to save lives in fighter-type aircraft. The tested algorithm includes both a 3-path and a 5-path avoidance technique that is compared to an optimal solution which minimizes aircraft control to avoid terrain. The research utilizes …

Development Of Design A Drop-In Hydrogen Fueling Station To Support The Early Market Buildout Of Hydrogen Infrastructure, Abdulhakim Amer A. Agll, Tarek A. Hamad, Yousif M. Hamad, Sushrut G. Bapat, John W. Sheffield

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper provides a design of a drop-in hydrogen fueling station. Drop-in stations are expected to be an important factor in the introduction of hydrogen fueling infrastructure. The stations not only allow a streamlined introduction of hydrogen in the vehicle fueling infrastructure, but also, acts as mini pilot plants that can allow for detailed control studies. The effect of the location and availability of utilities, the closeness to residential area, unintended safety concerns, people outlook towards hydrogen, etc. are some of the factors that can be readily studied with such drop-in stations. The proposed design of a drop-in station mainly …

Session B-4: Stem Integration: Statistics Is The Connection, Karen Togliatti, Lindsey Herlehy

Professional Learning Day

In this activity, participants will complete a STEM-integrated lesson incorporating problems in aerodynamics. Using the mathematical, science and engineering practice standards, they will design and model parachutes to determine a life-size chute to support their body weight. Participants will also consider design criteria for rate of descent, and graphically represent data and mathematical information as a scatter plot.

A Study On Flow Development In An Apu-Style Inlet And Its Effect On Centrifugal Compressor Performance, Fangyuan Lou

Open Access Dissertations

The objectives of this research were to investigate the flow development inside an APU-style inlet and its effect on centrifugal compressor performance. The motivation arises from the increased applications of gas turbine engines installed with APU-style inlets such as unmanned aerial vehicles, auxiliary power units, and helicopters. The inlet swirl distortion created from these complicated inlet systems has become a major performance and operability concern. To improve the integration between the APU-style inlet and gas turbine engines, better understanding of the flow field in the APU-style inlet and its effect on gas turbine is necessary.

A research facility for the …

Lunar Icecube Space Mission, Robert J. Twiggs, Eric Jerde

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Professors Bob Twiggs and Eric Jerde titled "Lunar IceCube Space Mission" from March 1, 2016.

Effect Of Low Velocity Impact On The Vibrational Behavior Of A Composite Wing, Richard M. De Luna

Master's Theses

Impact strength is one of the most important structural properties for a designer to consider, but it is often the most difficult to quantify or measure. A major concern for composite structures in the field is the effect of foreign objects striking composites because the damage is often undetectable by visual inspection. The objective for this study was to determine the effectiveness of using dynamic testing to identify the existence of damage in a small scale composite wing design. Four different impact locations were tested with three specimens per location for a total of 12 wings manufactured. The different impact …

Cognitive Loading, Affect Regulation And Aerodynamic Considerations In Uninhabited Aerial Vehicle Systems Refueling Operations, Sam Holley, Ian R. Mcandrew

Publications

Factors influencing aerodynamics involved in aerial refueling illustrate the potential for specialist operators to manage these operations for remotely piloted vehicles. The authors review aerodynamic characteristics of uninhabited aerial systems during refueling, drogue and boom design and associated flight dynamics, cognitive factors associated with control transfer and refueling, and affective components and their influence on decision making and operator performance. Attention is directed to cognitive loading and encoding challenges, with considerations for hippocampal mapping and hemispheric asymmetry. Implications for system state awareness are examined. Advantages for specially trained refueling pilot operators are discussed and recommendations given for areas of concentration.

Thermal Transport Properties Of Dry Spun Carbon Nanotube Sheets, Heath E. Misak, James L. Rutledge, Eric D. Swenson, Shankar Mall

Faculty Publications

The thermal properties of carbon nanotube- (CNT-) sheet were explored and compared to copper in this study. The CNT-sheet was made from dry spinning CNTs into a nonwoven sheet. This nonwoven CNT-sheet has anisotropic properties in in-plane and out-of-plane directions. The in-plane direction has much higher thermal conductivity than the out-of-plane direction. The in-plane thermal conductivity was found by thermal flash analysis, and the out-of-plane thermal conductivity was found by a hot disk method. The thermal irradiative properties were examined and compared to thermal transport theory. The CNT-sheet was heated in the vacuum and the temperature was measured with an …

Overview Of Eps-1 For Spacecraft, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on an "Overview of EPS-1 for Spacecraft" from Febuary 15, 2016.

Overview Of Eps-2 For Spacecraft, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on an "Overview of EPS-2 for Spacecraft" from February 15, 2016.

Sound Attenuation In Amorphous Silica At Frequencies Near The Boson Peak, Zhi Liang, Pawel Keblinski

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We Use Molecular Dynamics Phonon Wave Packet (WP) Simulations to Study Acoustic Propagation and Attenuation in Amorphous Silica (A-SiO₂) at Frequencies Near the Boson Peak (BP) Position and Compare Them with the Results of Equilibrium Molecular Dynamics (EMD) Simulations. the Sound Attenuation Coefficients Obtained from WP Simulations Are Generally Consistent with Those from EMD Predictions and Have Reasonable Agreement with the Existing Experimental Data. Near the BP Position, We Found the Frequency-Dependent Sound Attenuation Coefficients for Longitudinal and Transverse Modes Both Follow the Rayleigh-Scattering Fourth Power Law. above the BP Frequency, However, the Propagating Phonon is Essentially Attenuated …

Citizen Satellite: A Way To Have Low Cost Space Missions For The Unordinary Innovator, Robert J. Twiggs, Amin Djamshidpour, Ted Tagami, Tony So

Robert "Bob" Twiggs STEM Education Collection

A report written by Robert Twiggs, Amin Djamshidpour, Ted Tagami, and Tony So on February 9, 2016.

Hybrid Clutch Assembly For An Aircraft, Richard P. Anderson, Charles N. Eastlake, Matt Gonitzke, Glenn P. Greiner

Publications

A hybrid clutch assembly inserted between an internal com bustion engine and the propeller of an aircraft to provide a hybrid-powered aircraft. The hybrid clutch assembly allows a direct current (DC) electric motor to be attached to the hybrid clutch assembly using drive belts. The hybrid clutch assembly allows the internal combustion engine to transmit power to the aircraft's propeller and freely spin the DC motor. The DC motor can transmit power to the aircraft's propeller without turning the internal combustion engine. The hybrid clutch assembly independently allows either the internal combus tion engine or the DC motor in parallel …