Aerospace Engineering Commons^™

Analysis Of Electric Double Layer Structure Formed During Corrosion Of Steel Pipes Carrying Potable Water, Tanmay Sanjeev Gupte

Mechanical and Aerospace Engineering Theses - Archive

Corrosion of steel pipes carrying drinking water is a universal issue. It affects human health as the corrosion sediments in these pipes can be toxic and unfit for consumption. Further, the amassing of the corrosion products can lead to operational difficulties. Drinking water consists of anions like carbonate, hydroxides and chloride ions which are responsible for the corrosion process. In such types of aqueous corrosion, there is an interfacial region formed between the corroding metal and the bulk of the aqueous environment. This interfacial region is called the Electrical Double Layer. In this article, we direct to study the effects …

Reliability Challenges In Airside Economization And Oil Immersion Cooling, Jimil Manojbhai Shah

Mechanical and Aerospace Engineering Theses - Archive

The Datacom facility which comprises rooms or closets used for communication, computers/servers or electronic equipment requires cooling unit which consumes 31% (23% HVAC cooling + 8% HVAC fans) of overall energy. The ASHRAE TC9.9 subcommittee, on Mission Critical Facilities, Data Centers, Technology Spaces, and Electronic Equipment, has suited the data center’s executives by permitting brief period outings of the environmental conditions outside the prescribed temperature-humidity range, into passable extents A1-A4. To comprehend the expanding server densities and the required cooling vitality costs, data center operators are falling back on cost cutting measures. For instance, they are not firmly controlling the …

Harvesting Of Water From Fog Using Sponges, Jae Jun Lee

Mechanical and Aerospace Engineering Theses - Archive

Supervising Professor: Cheng Luo A sponge has porous structures. It is capable of both storing and transmitting water. In this work, we explored the possibility of applying three different types of sponges to collect fog. We also compared their fog-collection efficiencies with that of a typical Raschel mesh that is widely used in the field to collect fog. We found that, for three different fog speeds, the fog-collection efficiencies of three tested sponges were 39% to 93% those of the typical Raschel mesh, indicating that the sponges could serve as alternative fog collectors when well-developed collectors were not available. Sponge …

Flight Test Investigation On The Effects Of Aircraft Flap Configuration Change On Longitudinal Trim, Tiziano Bernard

Theses and Dissertations

Loss of Control (LOC) in general aviation has been a topic of extensive study and analysis in the United States and the European Union due to a long series of aircraft accidents in the past decades. The National Transportation Safety Board (NTSB) has identified over 1500 accidents in the traffic pattern involving LOC in general aviation aircraft between 1982 and 2015. LOC has often been attributed to deficiencies in pilot training, and the typical recommendation to reduce the number of accidents is to provide further training in stalls and spins. The European Aviation Safety Agency (EASA) has performed research that …

Cooling And Packaging Of Accumulators For Formula Sae Electric Car, Hang Yin

Mechanical and Aerospace Engineering Theses - Archive

Electric car is the future of automotive industry. The performance of the batteries is vital for that of electric cars. Overheating will compromise the performance of batteries, shorten the life span and even damage the battery permanently. So it is crucial to have an efficient packaging and cooling method. This project using Formula SAE Electric car as the testing ground is dedicated to develop the efficient way of thermal and electronic packaging of accumulators for automobiles.

Development And Flight Test Of Moving-Mass Actuated Unmanned Aerial Vehicle, Sampath Reddy Vengate

Mechanical and Aerospace Engineering Theses - Archive

Conventional airplane control is achieved by aerodynamic control surfaces by generating moments around all the three axes of the aircraft. Defections of the control surfaces have some disadvantages such as induced drag, increase in radar signature, and exposure to high temperature in high speed applications. As an alternative moment generation mechanism, prior research proposed internal mass-actuation, which is to generate gravitational moment by changing the center of gravity of the aircraft through motion of internal masses within the aircraft. Prior research investigated the feasibility and benefit of internal mass-actuation in airplane control based on simulation analysis. The main focus of …

Numerical Studies On Spin Coating Of Metals, Varun Nanjunda Rao Viswamithra

Mechanical and Aerospace Engineering Theses - Archive

Spin coating is a surface coating process which involves spreading a liquid dispensed on the center of a rotating substrate. The liquid is discharged using a suitable method on to the substrate rotating at a constant angular speed. The spinning speed is controlled to obtain a coating of desired thickness with faster spinning resulting in thinner coating. The thickness of the coating also depends on the properties of the fluid and other process parameters. Centrifugal force is introduced into the code as radial component of acceleration. The first part of the code solves the continuity and the Navier-Stokes equations, with …

Cfd Analysis And Design Optimization Of Heat Sink For Oil Immersion Cooling, Koushik Epuri

Mechanical and Aerospace Engineering Theses - Archive

Air cooling is predominant cooling technique employed in most of the data centers. As the demand for High performance computing (HPC) which deploy large concentration of high-end servers (30 kW to 200 kW per rack) is increasing, it is becoming challenging to cool the systems using air cooling. Liquid cooling has significant advantages over air cooling techniques due to higher heat capacities of fluids. Liquid immersion cooling using dielectric and non-corrosive mineral oils is one of the potential alternative to air cooling methods for high density data centers. In this work, we consider a third generation open compute server optimized …

Design And Stiffness Optimization Of Quadri-Directional Composite Grid Lattice Structures, Gajendra Devanga Gangadara

Mechanical and Aerospace Engineering Theses - Archive

Composite grid structures are rib stiffeners connected to each other rigidly in a pattern or a lattice such that the whole grid pattern has certain smeared stiffness property and has a certain structural behavior. The main focus of this thesis is to design the geometric pattern of a Quadri-directional composite grid lattice such that it has the prescribed stiffness moduli. The research is divided into three phases, in the first phase, the equation for stiffness moduli, the reduced stiffness matrix [Q] and the laminate stiffness matrices [ABD] of the grid pattern is derived for Quadri-directional grid panels. In the second …

Experimental, Numerical, And Analytical Slosh Dynamics Of Water And Liquid Nitrogen In A Spherical Tank, Jedediah Morse Storey

Theses and Dissertations

Understanding, predicting, and controlling fluid slosh dynamics is critical to safety and improving performance of space missions when a significant percentage of the spacecraft’s mass is a liquid. Computational fluid dynamics simulations can be used to predict the dynamics of slosh, but these programs require extensive validation. Many experimental and numerical studies of water slosh have been conducted. However, slosh data for cryogenic liquids is lacking. Water and cryogenic liquid nitrogen are used in various ground-based tests with a spherical tank to characterize damping, slosh mode frequencies, and slosh forces. A single ring baffle is installed in the tank for …

Time-Of-Flight Based Sonic Speed Measurements For Cold Gas Thruster Development, Brandon W. Kempf

Mechanical Engineering Undergraduate Honors Theses

The purpose of this thesis is to explore an experiment developed for validating the usage of a gaseous solution of water and propylene glycol for cold gas propulsion. The experiment involves a “Time of Flight” method of calculating the speed of sound in the gas and the corresponding specific heat ratio using a copper tube, two MEMS microphones, a piezoelectric speaker, and data-acquisition hardware. The experiment was calibrated using the known thermodynamic properties of air. The accuracy of the experiment was found to be within 0.6% for calculations of the speed of sound in air and within 1.0% of the …

A Cross-Sectional And Mixed-Method Assessment Of Safety Culture And Safety Climate At A Regional Airline, Micah S. Walala

Open Access Dissertations

The researcher applied a mixed methods approach to conduct a cross-sectional assessment of the safety culture, safety climate, and SMS at a regional airline in the United States. Data collection techniques were comprised of interview, on-line-survey, and a focus group activity. Participants in the current study were maintenance technicians, flight attendants, dispatchers, pilots, and managers. Results indicated significant differences of perception of safety climate, safety culture, and Safety Management System between the maintenance technicians and flight attendants. The length of time a participant had worked at the subject airline and age of the participant appeared to be significant factors of …

A Radial Basis Function Method For Solving Optimal Control Problems., Hossein Mirinejad

Electronic Theses and Dissertations

This work presents two direct methods based on the radial basis function (RBF) interpolation and arbitrary discretization for solving continuous-time optimal control problems: RBF Collocation Method and RBF-Galerkin Method. Both methods take advantage of choosing any global RBF as the interpolant function and any arbitrary points (meshless or on a mesh) as the discretization points. The first approach is called the RBF collocation method, in which states and controls are parameterized using a global RBF, and constraints are satisfied at arbitrary discrete nodes (collocation points) to convert the continuous-time optimal control problem to a nonlinear programming (NLP) problem. The …

Effects Of Radiation Heating On Additively Printed Hybrid Fuel Grain Oxidizer-To-Fuel Ratio Shift, Stephen L. Merkley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis examined the hypothesis that radiative heat transfer in small-scale printed-fuel hybrid rocket motors is responsible for the observed decreasing oxidizer-to-fuel (O/F) ratio shift. The magnitude of the radiation term was negligible for the motor sizes and types of propellants that have been previously tested, but was reintroduced in this study. To prove this hypothesis, a detailed enthalpy balance model was developed and tested using experimental fuel regression rate data obtained from a variety of motor scales using additively-manufactured acrylonitrile butadiene styrene (ABS) fuel grains.

Safte-Vat Functionality Effects On Flight Instructors' Situation Awareness And Instrument Student Pilots' Performance During Ftd Training, Rafael E. Abreu Vega

Doctoral Dissertations and Master's Theses

SAFTE-VAT is a virtual air traffic control systems that adds the capability to integrate automated air traffic control functionality and generate semiautonomous and autonomous air traffic to the Frasca 172S level 6 plus FTD to improve behavioral fidelity and to facilitate flight instructors the capacity to focus more on instructing student pilots instead of role-playing ATC duties. While SAFTE-VAT may offer a more realistic ATC interaction experience onboard the FTD that may result in a positive transfer of training increase, the effects on flight instructors’ situation awareness and overall student pilot performance are uncertain. In this small study, flight instructors …

An Experimental Study Of Momentum-Driven Unsteady Jets, Sravan Kumar Artham

Doctoral Dissertations and Master's Theses

Jets are seen commonly in nature and engineering and can be broadly classified into steady and unsteady jets. The study of unsteady jets has received little attention when compared to its steady counterpart. A type of unsteady jet is the turbulent puff which is a momentum driven jet in which fluid is ejected from a jet orifice intermittently. Common examples of turbulent puff like jets are coughs and volcanoes. The studies on momentum driven unsteady jets have primarily focused on single ejection events (single puffs) where an instantaneous supply of momentum drives the source fluid downstream of a nozzle. This …

Computational Investigation Of Impingement Cooling For Regeneratively Cooled Rocket Nozzles, Bianca A. De Angelo

Doctoral Dissertations and Master's Theses

Jet impingement cooling is an internal cooling configuration used in the thermal management of temperature sensitive systems. With rocket engine combustion temperatures rising as high as 3600 K, it is essential for a cooling method to be applied to ensure that the nozzle integrity can be maintained. Therefore, a novel heat transfer study is conducted to investigate if jet impingement cooling is feasible for a regenerative cooling rocket nozzle application. Regenerative cooling for liquid propellant rockets has been widely studied. However, to the best of the author’s knowledge, there is currently no literature describing this method in conjunction with impingement …

Investigation Of Pin Fin Cooling Channels For Applications In Gas Turbines, Royce Fernandes

Doctoral Dissertations and Master's Theses

Gas turbine blades are often cooled using internal cooling channels to prevent failure at temperatures beyond material limitations. Pin fin channels are commonly used on the trailing edge of the blades, where they enhance heat transfer and also provide structural support. This study focuses on the validation of several commercially available RANS turbulence models in CFD, that are used to computationally simulate the flow features inside a pin fin cooling channel. Turbulence models investigates are: Menter’s kω SST, realizable k-ε, and a quadratic formulation of the realizable k-ε model. The geometry investigated is a staggered 8 row pin fin channel. …

The Effect Of Axial Spacing Of Constant And Variable Blockages On The Deflagration-To-Detonation Transition In A Pulse Detonation Engine, Nicole Gagnon

Doctoral Dissertations and Master's Theses

An investigation was conducted into the effects of obstacle spacing on the deflagration-to-detonation transition section length in a pulse detonation engine. Testing was conducted with one hundred and ninety-five different obstacle, and spacing configurations. The configurations included constant, as well as variable spacing between obstacles. The goal of this investigation was to correlate the spacing between obstacles and the blockage ratio of the obstacles with the detonation success and the shortening of the DDT section. The ten cases that achieved the highest percentage of detonations were investigated further to determine the distance needed for the deflagration-to-detonation transition. A 33% blockage …

Optical Tracking And Spectral Characterization Of Cubesats For Operational Missions, Forrest Gasdia

Doctoral Dissertations and Master's Theses

Orbital debris in low Earth orbit is of growing concern to operational satellites from the government and commercial sector. With an uptick in worldwide satellite launches and the growing adoption of the CubeSat standard, the number of small objects in orbit are increasing at a faster pace than ever. As a result, a cascading collision event seems inevitable in the near future.

The United States Strategic Command tracks and determines the orbit of resident space objects using a worldwide network of radar and optical sensors. However, in order to better protect space assets, there has been increased interest in not …