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Methods For Decarbonized Aeroengine Combustor Design, Robert T. Prater

Masters Theses

There exists an urgent need to decarbonize the civil transportation sector in order to address global warming concerns and its effects. Alternate and sustainable fuel types for combustion systems must be pursued to mitigate the dependency on fossil fuels for power generation. Possible alternative options for aeroengine combustion and propulsion include batteries or hydrogen fuel for fuel-cells or thermal-powered gas turbines. More specifically, thermal-powered aeroengines with premixed flame regimes can promise ultra-low emissions. Future aeroengine combustors operating in highly swirled premixed mode with hydrogen/air mixtures are central to this paper. Prior to the implementation and design of such systems, premixed …

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 …

Thermodynamic Analysis Of An Autogenous Pressurization System, Samuel H. Smith

Masters Theses

Pressurized gas feed systems have been vital to spacecraft where a pump-fed design would prove too large, heavy, or complicated to be effective. This project investigates autogenous pressurization – a pressurized feed system where the intentional vaporization of liquid propellant to fill the ever-increasing ullage space with its own warm, low-density gas. Motivation for this research originates from the University of Tennessee Space Institute’s (UTSI) contract with Gloyer-Taylor Laboratories (GTL) to assist the development of an innovative pressurization system.

While other pressurization systems have been studied and used extensively, modeling of an autogenous system is less established. Despite the relative …

The Effects Of Geometry And Material Variations On The Onset Voltage Of Electrospray Emitters, Justin Michael Jones

Masters Theses

Electric propulsion is becoming an increasingly desirable technology as space missions become more complex and more commonplace. Electrospray propulsion specifically is proving promising as a low-thrust, high specific impulse technology with the ability to execute very precise thrust maneuvers in applications such as attitude adjustments to small satellites. Electrospray devices operate by electrostatic acceleration of charged droplets and/or ions to produce thrust. The current technological trend is to drive these devices towards the micro-scale. To become a viable space propulsion technology, the manufacturability, the required footprint, and the power requirements of electrospray devices are areas which must be addressed. With …

Development, Analysis, And Optimization Of A Swirl-Promoting Mean Flow Solution For Solid Rocket Motors, Andrew Steven Fist

Masters Theses

This work demonstrates and analyses a new flow candidate for describing the internal gaseous motion in simulated rocket motors. The fundamental features of this solution include the conservation of key system properties also incorporated in the classic Taylor-Culick (TC) system (i.e. inviscid, axisymmetric, steady and rotational properties), while allowing for the development of a swirling velocity component. The work compares the new solution to the development and formulation of the classic TC system, ultimately identifying that both the new and classic solutions are special cases of the Bragg-Hawthorne equation. Following this development, the text then explores the development of energy-optimized …

Analysis Of Flammability Limits And Gas Properties Of A Solid Rocket Motor Test In A High Altitude Test Facility, Richard Scott Kirkpatrick

Masters Theses

The testing of solid and liquid rocket propulsion systems in a confined test facility often produces explosive or flammable gases which must be safely handled. Often inert gases such as nitrogen are used to lower the molar fraction of oxygen to low enough levels to minimize the probability of an explosion or deflagration. For this thesis, the chemical composition of these rocket exhaust gases mixed with air were used to determine the flammability limits of the gas mixture. Using the ideal gas law and the conservation of mass, the exhaust gas composition and gas properties such as pressure, temperature, volume …

A Comparative Study Of The Gas Turbine Simulation Program (Gsp) 11 And Gasturb 11 On Their Respective Simulations For A Single-Spool Turbojet, Rayne Sung

Masters Theses

GasTurb 11 and the Gas Turbine Simulation Program (GSP) 11 are two commercially available gas turbine simulation programs used by industrial professionals and academic researchers throughout the world. The two programs use a pseudo-perfect gas assumption in their calculations, where the specific heat is taken as a function of temperature and gas composition but not pressure. This assumption allows the two programs to make more realistic calculations of gas turbine engine performance. This is in contrast to the ideal and perfect gas assumptions used in classroom calculations. In addition, GasTurb 11 and GSP 11 both utilize component maps, comprised from …

A Survey Of Gaps, Obstacles, And Technical Challenges For Hypersonic Applications, Timothy Andrew Barber

Masters Theses

The object of this study is to canvas the literature for the purpose of identifying and compiling a list of Gaps, Obstacles, and Technological Challenges in Hypersonic Applications (GOTCHA). The significance of GOTCHA related deficiencies is discussed along with potential solutions, promising approaches, and feasible remedies that may be considered by engineers in pursuit of next generation hypersonic vehicle designs and optimizations. Based on the synthesis of several modern surveys and public reports, a cohesive list is formed, consisting of widely accepted areas needing improvement and falling under several general categories. These include: aerodynamics, propulsion, materials, analytical modeling, CFD modeling, …

Computational Investigations Of Characteristic Performance Improvements For Subkilogram Laser Micropropulsion, Richard Joel Thompson

Masters Theses

Experimental investigations have evaluated the feasibility of using laser-driven plasma microthrusters for small-thrust, high-specific-impulse space maneuvers, particularly for micro- and nanosatellite missions. Recent work made use of the Mach2 hydromagnetics code for the construction of an adequate computational model of the micro-thruster opera- tion. This thesis expounds on this previous work by extending the computational modeling capabilities, allowing for the determination of plasma plume properties and characteristic performance assessment of the microthruster; this allows for further computational investi- gation of the performance improvements achieved by new design considerations. Two par- ticular design changes are implemented and measured: (i) the simulation …