Mechanical 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 …

A Numerical Optimization Study Of A Novel Electrospray Emitter Design, Joshua H. Howell

Masters Theses

The low thrust and high specific impulse of electric propulsion has been brought to the forefront for CubeSat and small spacecraft applications. Electrospray thrusters, which operate via electrostatic principles, have seen much research, development, and application in recent years. The small sizes of the spacecraft that utilize electrospray thrusters has focused development into the miniaturization of this technology to the micro-scale. Miniaturization introduces design challenges that must be addressed, including power supply mass and footprint requirements. This consequence requires investigation into the effects of design choices on the thruster onset voltage, defined as the voltage at which ion emission begins. …

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 …

Design And Fabrication Of A Low-Cost Turbine Engine Component Testbed (Tect), Joshua A. Hartman

Masters Theses

With gas turbine engine testing becoming very expensive because of the increasing complexity involved with the engine, engine subsystems, and test support systems, a low-cost Turbine Engine Component Testbed (TECT) is proposed. This engine build is given the designation J1-H-02. In the present study, a small augmented gas turbine engine (GTE) is constructed. The TECT engine is built with modularity as a key design consideration to allow for flame-tube patterns and augmentor sections to be changed quickly for combustion experiments that have gained impetus due to combustion anomalies/instabilities inherent with future military engine augmentors. This testbed allows for an effective …

A Method For Performance Analysis Of A Ramjet Engine In A Free-Jet Test Facility And Analysis Of Performance Uncertainty Contributors, Kevin Raymond Holst

Masters Theses

Ramjet and scramjet engines are being developed to provide a more fuel efficient means of propulsion at high Mach numbers. Part of the development of these engines involves test and evaluation of an engine in ground facilities as well as in flight. Ground facilities, like Arnold Engineering Development Center (AEDC) and those at engine manufacturers like General Electric (GE) and Pratt & Whitney (PW), have decades of experience testing traditional turbine engines and much less experience testing full scale ramjet engines.

Testing a supersonic engine model in a free-jet mode presents a host of challenges not experienced during traditional direct …

Continuously Variable Rotorcraft Propulsion System: Modelling And Simulation, Naveen Kumar Vallabhaneni

Masters Theses

This study explores the variable speed operation and shift response of a prototype of a two speed single path CVT rotorcraft driveline system. Here a Comprehensive Variable Speed Rotorcraft Propulsion system Modeling (CVSRPM) tool is developed and utilized to simulate the drive system dynamics in steady forward speed condition. This investigation attempts to build upon previous variable speed rotorcraft propulsion studies by:

1) Including fully nonlinear first principles based transient gas-turbine engine model

2) Including shaft flexibility

3) Incorporating a basic flight dynamics model to account for interactions with the flight control system.

Through exploring the interactions between the various …

Effects Of Supercooled Water Ingestion On Engine Performance, Rick Hutchings

Masters Theses

An aircraft will encounter freezing rain, snow, and ice during ground operation and flight. In cold conditions, ice may form on th einlet and internal stators and rotors of the gas turbine engine. When ice accumulates on blades (and/or stators), the aerodynamic characteristics of the blades change due to the altered size, shape, and roughness. This change causes the blade to no longer operate at its design point and decreases compressor performance. Therefore, characterization of the aerodynamic performance is required to define the associated losses due to the effects of supercooled liquid water ingestion. This characterization can be accomplished through …

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 …