Aerospace Engineering Commons^™

Reduced-Order Analysis Of Dual Mode Supersonic Combustion Ramjet Propulsion System, Vijay Gopal

Mechanical and Aerospace Engineering Theses

High speed propulsion systems typically possess relatively simple geometry but the complexity involved in the flow characteristics makes their analysis a challenging task. The current research work introduces a reduced order analytical model for a steady operation of dual mode SCRamjet (Supersonic Combustion Ramjet) propulsion system at design and off-design conditions. The model hopes to reduce analysis time and complexity to carry out parametric sweep studies for preliminary design of SCRamjet engines. The analytical model splits the analysis of SCRamjet engine into five interactive components namely: inlet, isolator, injector, burner and nozzle. Each component is modelled using physics of gas-dynamics …

Heat Removal Analysis Using Ntu Microscopic Theory And Experimental Fluid Testing Of Radaitors, Pumps And Fans For The Thermal Management System Of Formula Sae Electric Racecar, Shahzad Shahrukh Bulsara

Mechanical and Aerospace Engineering Theses

Formula SAE at UT Arlington has always been building well engineered race cars, further being one of the top teams in The United States. However, an electric race car being first in the fleet, cooling of electric motors played a vital role. The thermal system being significantly different from combustion cars, consists of a lower heat application. It is always favorable to maintain electronics as close to ambient temperature as compared to its counter hydro-mechanical engines. To attain the objective, a complete thermal & fluid analysis was carried out using the NTU method/ microscopic theory and experimental results associated towards …

Assessing Interlaminar Shear Stress-Strain Curves In Tape Composites Based On The Flat-Plate Torsion Method, Gary Steven Grohman

Mechanical and Aerospace Engineering Theses

Composites are attractive for structural applications in the aerospace industry for their high strength to weight ratio, stiffness, and low density. The development and implementation of composite structures has grown rapidly through the aerospace industry exceeding our ability to characterize the material properties due to costly and time consuming test methods. The ability to fully characterize the nonlinear stress-strain relationship in the 1-3 and 2-3 principal planes up to the point of failure is extremely important for predicting failures in composites. The principal directions for composites are the fiber direction, transverse direction, and the thru thickness direction, commonly referred to …

Performance Analysis Of A Helium Cooled Vhtr Powered Brayton Cycle Topping Unit On An Existing Steam Cycle Using Numerical Propulsion System Simulation, Warren Romao Caetano Freitas

Mechanical and Aerospace Engineering Theses

With the decommissioning of ageing coal power plants due to outdated technology and high levels of air pollution, the advantages of overhauling existing infrastructure is twofold. First, by providing an alternate, sustainable fuel source, like nuclear power, the problem of air pollution can be brought to check. Second, utilizing existing steam plant infrastructure reduces initial investment costs and allows investors to keep the existing steam plant running until the new infrastructure is ready to go online.The focus of this research is to design and analyze the topping cycle required to support an existing 300 MW power plant based on the …

Efficient Method To Cool The Data Center Using Solar Energy, Krishna Desai

Mechanical and Aerospace Engineering Theses

Solar energy is the only source which is abundantly available and which can beused to power a cooling system that is based on absorption cycle.Solar cooling system can be used to provide refrigeration for food and medicinesand comfort cooling also. Such systems are specifically applicable to the large applications having large cooling loads for particularly big periods of a year. Peak demandfor the cooling of a building and the highest availability of solar radiation are in similar phase, which makes solar cooling of any building a potential energy source andalso a green solution.In this project, The Lithium bromide-water absorption cycle …

Manufacturing And Characterization Of Ultra Light Bio-Inspired Nanocomposite Structures, Sushma Pothana

Mechanical and Aerospace Engineering Theses

The inner part of bones is spongy cell-type three dimensional structure called cancellous bone which is the major contributor in keeping the bone weight very low. Yet, bone can sustain body weight and reasonable impact loads implying bone is a naturally optimized light-weight but strong structure. This study demonstrates a novel approach to manufacture bone-like nanocomposite structure for weight saving structural applications. For this, Silicon Carbide (SiC )nano particles are dispersed in SC-15 epoxy resin (a two part liquid resin that solidifies when mixed together at room temperature). Using our novel 3D+ manufacturing technique we developed lighter but stronger nanocomposite …

Analytical Modeling Of Helium Turbomachinery Using Fortran 77, Purushotham Balaji

Mechanical and Aerospace Engineering Theses

Advanced Generation IV modular reactors, including Very High Temperature Reactors (VHTRs), utilize helium as the working fluid, with a potential for high efficiency power production utilizing helium turbomachinery. Helium is chemically inert and nonradioactive which makes the gas ideal for a nuclear power-plant environment where radioactive leaks are a high concern. These properties of helium gas helps to increase the safety features as well as to decrease the aging process of plant components.The lack of sufficient helium turbomachinery data has made it difficult to study the vital role played by the gas turbine components of these VHTR powered cycles. Therefore, …

Numerical Investigation Of Steady State And Transient Thermal Performance Of A Multi-Chip Vapor Chamber, Mohammad Parhizi

Mechanical and Aerospace Engineering Theses

Effective dissipation of heat generated in microelectronic devices during operation is critical for reliability and performance, particularly for advanced architectures such as microserver chips. Vapor chambers are a class of heat spreaders that have received much recent attention due to their passive nature and superior heat spreading capability. Several studies have investigated thermal performance of vapor chambers as heat spreading devices. However, developing a simple and accurate model which could be easily used in industry is still a big challenge. Moreover, more work needs to be done to optimize the performance of vapor chambers. For instance, developing a vapor chamber …

Chip Package Interaction Study To Analyze The Mechanical Integrity Of A 3-D Tsv Package, Pavan Rajmane

Mechanical and Aerospace Engineering Theses

The convergence and miniaturization of computing and communications dictates building up rather than out. As planar device miniaturization continues to its ultimate limits, the complexity of circuit interconnections for 2-D devices becomes a limitation for performance and drives up power dissipation [1]. As the consumers demand more functions on their hand-held electronic devices, the need for more devices such as memory, CPU and GPU in hand-held type footprints is increasing. Chip-stacking (3-D) is emerging as a powerful tool that satiates such IC package requirements. A 3-D FPGA would overcome the interconnect limitations, resulting in greater silicon efficiency per function (number …

Uncertainty Estimates And Prediction Interval Development For Internal Strain Gage Balance Calibration Systems, Kenneth G. Toro

Mechanical & Aerospace Engineering Theses & Dissertations

Currently, there is a lack of the use of mathematically rigorous methods to evaluate the performance of multivariate force measurement systems. The specific problem addressed in the research stems from the practical issues faced by test engineers when wind tunnel models with internal strain gage balances are readied for test. Check loads are applied and the question that needs to be answered is whether or not the balance is reading within acceptable limits. These systems tend to be difficult to characterize uncertainty, primarily due to their multivariate nature, but also due to the desire for an estimate on the explanatory …

Use Of Single Stage Model Rockets To Teach Some Engineering Principles And Practices To First Year Engineering And Engineering Technology Students, Hüseyin Sarper, Linda Vahala

Electrical & Computer Engineering Faculty Publications

Model rocketry has been called miniature astronautics; a technology in miniature, a hobby, a sport, a technological recreation, an educational tool, and it is all of these things. This paper will describe student projects using model rockets and engines to learn engineering principles for launching rockets and determining the apogee. Model rocketry is a powerful tool for instructors who wish to incorporate science, technology, engineering, and mathematics into a fun, engaging, and challenging activity for first year engineering students. The apogee can be determined using four distinct methods: trigonometry using hand held angle measuring tools, onboard altimeter devices, analytical calculations …

Experimental Investigation Of Wall Shear Stress Modifications Due To Turbulent Flow Over An Ablative Thermal Protection System Analog Surface, Jacob Helvey

Theses and Dissertations--Mechanical Engineering

Modifications were made to the turbulent channel flow facility to allow for fully developed rough quasi-2D Poiseuille flow with flow injection through one surface and flow suction through the opposing surface. The combination of roughness and flow injection is designed to be analogous to the flow field over a thermal protection system which produces ablative pyrolysis gases during ablation. It was found that the additional momentum through the surface acted to reduce skin friction to a point below smooth-wall behavior. This effect was less significant with increasing Reynolds number. It was also found that the momentum injection modified the wake …

Shape Memory Behavior Of Single Crystal And Polycrystalline Ni-Rich Nitihf High Temperature Shape Memory Alloys, Sayed M. Saghaian

Theses and Dissertations--Mechanical Engineering

NiTiHf shape memory alloys have been receiving considerable attention for high temperature and high strength applications since they could have transformation temperatures above 100 °C, shape memory effect under high stress (above 500 MPa) and superelasticity at high temperatures. Moreover, their shape memory properties can be tailored by microstructural engineering. However, NiTiHf alloys have some drawbacks such as low ductility and high work hardening in stress induced martensite transformation region. In order to overcome these limitations, studies have been focused on microstructural engineering by aging, alloying and processing.

Shape memory properties and microstructure of four Ni-rich NiTiHf alloys (Ni50.3Ti29.7Hf20, Ni50.7Ti29.3Hf20, …

Inkjet Printing: Facing Challenges And Its New Applications In Coating Industry, Sadegh Poozesh

Theses and Dissertations--Mechanical Engineering

This study is devoted to some of the most important issues for advancing inkjet printing for possible application in the coating industry with a focus on piezoelectric droplet on demand (DOD) inkjet technology. Current problems, as embodied in liquid filament breakup along with satellite droplet formation and reduction in droplet sizes, are discussed and then potential solutions identified. For satellite droplets, it is shown that liquid filament break-up behavior can be predicted by using a combination of two pi-numbers, including the Weber number, We and the Ohnesorge number, Oh, or the Reynolds number, Re, and the Weber number, …

Ultra-Fast, Autonomous, Reconfigurable Communication System, Paul Bupe Jr

Electronic Theses and Dissertations

The recent years have witnessed an increase in natural disasters in which the destruction of essential communication infrastructure has significantly affected the number of casualties. In 2005, Hurricane Katrina in the United States resulted in over 1,900 deaths, three million land-line phones disconnections, and more than 2000 cell sites going out of service. This incident highlighted an urgent need for a quick-deployment, efficient communication network for emergency relief purposes. In this research, a fully autonomous system to deploy Unmanned Aerial Vehicles (UAVs) as the first phase disaster recovery communication network for wide-area relief is presented. As part of this system, …

The Space Infrastructure Vulnerability Cadastre: Orbital Debris Critical Loads, Adrian V. Gheorghe, Daniel E. Yuchnovicz

Engineering Management & Systems Engineering Faculty Publications

Orbital debris from over 50 years of human activity in space are threatening the operations of existing and future satellites and the sustainability of high-value satellite orbits. This technical memorandum calls for the development of a cadastre that depicts the vulnerability of critical satellite orbits to accumulating orbital debris. A space infrastructure vulnerability cadastre could serve as a governance tool for use by developers and operators of critical space infrastructures to better communicate the current and future vulnerability of high-value orbits to the accumulation of orbital debris. These high-value orbits are susceptible to "loss" for decades or centuries if generation …

Terrain Referenced Navigation Using Sift Features In Lidar Range-Based Data, Matthew T. Leines

Theses and Dissertations

The use of GNSS in aiding navigation has become widespread in aircraft. The long term accuracy of INS are enhanced by frequent updates of the highly precise position estimations GNSS provide. Unfortunately, operational environments exist where constant signal or the requisite number of satellites are unavailable, significantly degraded, or intentionally denied. This thesis describes a novel algorithm that uses scanning LiDAR range data, computer vision features, and a reference database to generate aircraft position estimations to update drifting INS estimates. The algorithm uses a single calibrated scanning LiDAR to sample the range and angle to the ground as an aircraft …

Cloud-Induced Uncertainty For Visual Navigation, Alyssa N. Gutierrez

Theses and Dissertations

This research addresses the numerical distortion of features due to the presence of clouds in an image. The research aims to quantify the probability of a mismatch between two features in a single image, which will describe the likelihood that a visual navigation system incorrectly tracks a feature throughout an image sequence, leading to position miscalculations. First, an algorithm is developed for calculating transparency of clouds in images at the pixel level. The algorithm determines transparency based on the distance between each pixel color and the average pixel color of the clouds. The algorithm is used to create a dataset …

Multi-Objective Trajectory Optimization Of A Hypersonic Reconnaissance Vehicle With Temperature Constraints, Tadeusz J. Masternak

Theses and Dissertations

Temperature-constrained optimal trajectories for a scramjet-based hypersonic reconnaissance vehicle were generated by developing an optimal control formulation and solving it using a variable order Gauss-Radau quadrature collocation method. The vehicle was assumed to be an air-breathing reconnaissance aircraft that has specified takeoff/landing locations, airborne refueling constraints, specified no-fly zones, and specified targets for sensor data collections. The aircraft model included fight dynamics, aerodynamics, and thermal constraints. This model was incorporated into an optimal control formulation that includes constraints on both the vehicle as well as mission parameters, such as avoidance of no-fly zones and coverage of high-value targets. Optimal trajectories …

Hot Streak Characterization In Serpentine Exhaust Nozzles, Darrell S. Crowe

Theses and Dissertations

Modern aircraft of the United States Air Force face increasingly demanding cost, weight, and survivability requirements. Serpentine exhaust nozzles within an embedded engine allow a weapon system to fulfill mission survivability requirements by providing denial of direct line-of-sight into the high-temperature components of the engine. Recently, aircraft have experienced material degradation and failure along the aft deck due to extreme thermal loading. Failure has occurred in specific regions along the aft deck where concentrations of hot gas have come in contact with the surface causing hot streaks. The prevention of these failures will be aided by the accurate prediction of …