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Full-Text Articles in Engineering

Reconstruction Of The 3d Temperature And Species Concentration Spatial Distribution Of A Jet Engine Exhaust Plume Using An Infrared Fourier Transform Spectrometer Hyperspectral Imager, Mason D. Paulec Sep 2018

Reconstruction Of The 3d Temperature And Species Concentration Spatial Distribution Of A Jet Engine Exhaust Plume Using An Infrared Fourier Transform Spectrometer Hyperspectral Imager, Mason D. Paulec

Theses and Dissertations

The measurement of combustion byproducts is useful for determining pollution of any fuel burning application, efficiency of combustion, and determining detectability of aircraft exhausts. Both intrusive and non-intrusive techniques have been utilized to measure these quantities. For the majority of the non-intrusive techniques, the absorption and emission spectra of the gases are utilized for measurements. For this research, the use of the Telops Infrared Fourier Transform Spectrometer (IFTS) Hyperspectral Imager (HSI) was explored within the scope of combustion diagnostic methods, as an option for remote measurements of a jet turbine to determine concentration of species and temperature of the combustion …


Investigation Of A Pressure Wave Supercharger For An Industrial Diesel Engine, Brian A. Beasley Sep 2018

Investigation Of A Pressure Wave Supercharger For An Industrial Diesel Engine, Brian A. Beasley

Theses and Dissertations

Internal combustion engines suffer from decreased performance as altitude is in- creased. This performance decrease can be overcome by increasing the pressure in the engine's intake manifold. Typically, this is accomplished with a turbocharger or supercharger. However, mechanical compression devices such as these suffer from decrease compression efficiency as the size of the device decreases. The size of the compression device scales with the amount of mass ow through the device, and the amount of mass ow is proportional to the size of the engine. This means a small turbocharger for a small engine is less efficient than a larger …


Application Of Spectral Solution And Neural Network Techniques In Plasma Modeling For Electric Propulsion, Joseph R. Whitman Sep 2018

Application Of Spectral Solution And Neural Network Techniques In Plasma Modeling For Electric Propulsion, Joseph R. Whitman

Theses and Dissertations

A solver for Poisson's equation was developed using the Radix-2 FFT method first invented by Carl Friedrich Gauss. Its performance was characterized using simulated data and identical boundary conditions to those found in a Hall Effect Thruster. The characterization showed errors below machine-zero with noise-free data, and above 20% noise-to-signal strength, the error increased linearly with the noise. This solver can be implemented into AFRL's plasma simulator, the Thermophysics Universal Research Framework (TURF) and used to quickly and accurately compute the electric field based on charge distributions. The validity of a machine learning approach and data-based complex system modeling approach …


Pseudo Linear Hall Effect Thruster Characterization Through Potential, Magnetic, And Optical Measurements, Braeden A. Sheets Mar 2018

Pseudo Linear Hall Effect Thruster Characterization Through Potential, Magnetic, And Optical Measurements, Braeden A. Sheets

Theses and Dissertations

Electric propulsion systems are a more mass efficient method for providing a change in velocity, ΔV, to on-orbit spacecraft, than their chemical counterparts. In comparison, electric systems generally have a much higher specific impulse, Isp, than chemical systems. One option within the realm of electric propulsion is Hall Effect Thrusters, which have moderately high specific impulse values. From their advent in the 1960s, Hall Effect Thrusters have been used for orbit station keeping, attitude control, and orbit transfer. Although the discharge cavity is conventionally circular, pseudo-linear or racetrack shaped cavities have been developed. Even though Hall thrusters have decades of …


Design, Buildup, And Testing Of A Radial Rotating Detonation Engine For A Compact Auxiliary Power Unit, Riley Huff Mar 2018

Design, Buildup, And Testing Of A Radial Rotating Detonation Engine For A Compact Auxiliary Power Unit, Riley Huff

Theses and Dissertations

Current power generators consume a large portion of the aircrafts usable volume and they are also extremely heavy for the amount of power that they can produce. Therefore, a need for compact, lightweight Auxiliary Power Units (APU) with high power density has arisen. A novel solution to this problem comes in the form of coupling a Rotating Detonation Engine (RDE) with a turbine generator. A new type of RDE referred to as the Radial Rotating Detonation Engine (RRDE) has been developed to fill this need. This project marks the first radial ow RDE successfully operated in the United States, and …


Characterization And Analysis Of Plasma Instabilities In A 600 W Permanent Magnet Hall Thruster, Samuel D. Wright Mar 2018

Characterization And Analysis Of Plasma Instabilities In A 600 W Permanent Magnet Hall Thruster, Samuel D. Wright

Theses and Dissertations

Electric propulsion is an important technology for the future of space operations and exploration. Within the range of electric propulsion devices, Hall Effect Thrusters provide a balance of thrust and specific impulse well-suited for many Earth-centric missions. Hall Effect Thrusters have been studied since their development in the 1960s and have been flown on hundreds of spacecraft, but the intimate details of the plasma behavior within the thruster exhaust plume are still not well understood. Furthering this knowledge may be key to improving thruster design to yield better performance and longer lifetimes. To this end, experiments were conducted to measure …


Analysis Of Additively Manufactured Injectors For Rotating Detonation Engines, Michael C. Waters Mar 2018

Analysis Of Additively Manufactured Injectors For Rotating Detonation Engines, Michael C. Waters

Theses and Dissertations

This research represents an experimental and computational analysis of additively manufactured injectors for Rotating Detonation Engines (RDEs) for use in rocket propulsion. This research was based on the manufacture and testing of existing injector element designs using additive techniques. The designs were modeled from geometries gathered from Sutton and Biblarz Elements of Rocket Propulsion [23]. The goal of this research was to characterize the viscous losses of each design based on the discharge coefficient. The designs were computationally simulated to gain insight to the flow characteristics using multiple sets of conditions for surface roughness and inlet pressure. The results were …