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Full-Text Articles in Propulsion and Power
Performance Analysis And Recommended Improvements Of A Cubesat Resistojet, Alexander M. Petrocelli
Performance Analysis And Recommended Improvements Of A Cubesat Resistojet, Alexander M. Petrocelli
Theses and Dissertations
A small resistojet design was evaluated for its current performance and assessed for design and operational improvements. This resistojet is designed to operate on AFIT CubeSats with the intent of providing 100-200 mN of thrust at a specific impulse between 66-104 seconds. Using previously collected data and studies conducted on the design, analysis was performed to determine the current performance of this first-generation design. This provided a starting point for performance analysis over a variety of operational temperatures and pressures. This process was conducted for various heat exchanger path lengths of both the current design and two adapted path geometries. …
Performance Study Of Post-Processed Additively Manufactured Low Thrust Nozzles, Tyler W. Gerhold
Performance Study Of Post-Processed Additively Manufactured Low Thrust Nozzles, Tyler W. Gerhold
Theses and Dissertations
This research explores metal post-processing techniques to effectively reduce the large anomalous protrusions found in small additively manufactured low thrust rocket nozzles. Research has found that nozzles of this kind can experience losses in thrust of over 40%. Analytic theory of adiabatic nozzle flow with viscous losses for additively manufactured nozzles does not align with what has been found when tested experimentally. Compressible flow losses, such as shock wave formation inside the nozzle diverging cone, are likely the leading causes of such loss. Reduction in nozzle irregularities can likely yield results seen in analytic theory with similar performance to traditional …
Design Of An Electro-Thermal Nanosatellite Propulsion System, James H. Founds
Design Of An Electro-Thermal Nanosatellite Propulsion System, James H. Founds
Theses and Dissertations
This research focused on designing an arcjet system with water as the propellant. Previous research developed a compact, reliable, and safe propellant storage and feed system. The goal is to combine the arcjet with the previous tank to achieve thrust and specific impulse characteristics greater than cold gas or resistojet system. This platform features a 1 U, non-hazardous, and sub-kilowatt powered propulsion system for nanosatellites. A simplified analysis of the design predicts thrust and specific impulse greater than can be achieved by cold gas or resistojet thrusters. Testing resulted in oxidation of the electrodes raising concerns about the longevity of …
Density Measurements Of Neutral Xenon Using Multiphoton Ionization And Microwave Spectroscopy In A Hall Effect Thruster, Taylor J. Foy
Density Measurements Of Neutral Xenon Using Multiphoton Ionization And Microwave Spectroscopy In A Hall Effect Thruster, Taylor J. Foy
Theses and Dissertations
A new dye laser and microwave scattering system for measuring low speed xenon particles was installed to characterize a commercially sourced 600 W Hall effect thruster. The new system uses multiphoton ionization and microwave spectroscopy to determine number density and velocity measurements of neutral xenon atoms in the plume of a Hall thruster. A study was conducted to ensure the new system will be able to accurately measure these neutrals in future work. The ultimate goal of this new system is to isolate and characterize the extra thrust produced in Hall Effect Thrusters due to finite volume vacuum chambers.
Characterization And Anomalous Diffusion Analysis Of A 100w Low Power Annular Hall Effect Thruster, Megan N. Maikell
Characterization And Anomalous Diffusion Analysis Of A 100w Low Power Annular Hall Effect Thruster, Megan N. Maikell
Theses and Dissertations
A Busek 100W low-power annular Hall effect thruster was characterized to determine the thruster’s best operating parameter range and to study plasma oscillations within the thruster. These experiments were conducted using xenon gas in the Space Propulsion Analysis and System Simulator chamber at the Air Force Institute of Technology on Wright-Patterson Air Force Base. The thruster’s performance characteristics were evaluated at nominal discharge voltages and constant total mass flow rate, solenoid current, and keeper current to determine the operating conditions optimizing divergence angle, beam efficiency, and discharge loss. This was accomplished using a Faraday probe to determine the plume’s current …
Sheet Velocity Measurements Using Laser Absorption Spectroscopy In A Xenon Hall Effect Thruster Plume, Avery W. Leonard
Sheet Velocity Measurements Using Laser Absorption Spectroscopy In A Xenon Hall Effect Thruster Plume, Avery W. Leonard
Theses and Dissertations
A new laser absorption spectroscopy (LAS) velocimetry system, designed to obtain 2D planar velocity fields for ionized Xenon in the plume of a Hall effect thruster by probing the transition of Xe II at 834.72 nm, was implemented at the Air Force Institute of Technology (AFIT) Space Propulsion Analysis and System Simulator (SPASS) Lab vacuum chamber. A single horizontal laser sheet was used to probe singly-ionized Xenon in the plume of a Busek BHT-600 Hall thruster and obtain a histogram of estimated axial velocity, to validate the system. Similar velocities to those obtained by an earlier intrusive characterization of the …
Application Of Spectral Solution And Neural Network Techniques In Plasma Modeling For Electric Propulsion, Joseph R. Whitman
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 …
Characterization And Analysis Of Plasma Instabilities In A 600 W Permanent Magnet Hall Thruster, Samuel D. Wright
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
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 …
Hall Effect Thruster Characterization Through Potential, Magnetic, And Optical Measurements, Nicholas L. Hyatt
Hall Effect Thruster Characterization Through Potential, Magnetic, And Optical Measurements, Nicholas L. Hyatt
Theses and Dissertations
Electric propulsion is a promising method for providing ΔV to spacecraft on orbit. In general, much higher ISPS are obtained compared to their chemical counterparts. Hall thrusters are a subset of electric propulsion with moderately high specific impulse and thrust when compared to other forms of electric propulsion. Even though Hall thrusters have an extensive flight legacy around the world, there are still many unknowns associated with their operation. Experimental research was conducted in AFIT’s Space Propulsion Application Simulation System (SPASS) laboratory, to measure Hall current, plasma potential and visible emission from the 600W Hall thruster in a …
Localized Plasma Measurement During Instability Modes In A Hall Thruster, David A. Cunningham
Localized Plasma Measurement During Instability Modes In A Hall Thruster, David A. Cunningham
Theses and Dissertations
Hall thrusters are a key technology for current and future unmanned satellites, striking a balance between thrust and fuel economy suitable for many mission profiles of interest. Despite their extensive flight heritage and a large body of research, many phenomena occurring in the plasma discharge of Hall thrusters are not well understood. A combination of intrusive and non-intrusive measurement techniques were used to investigate the properties of the exhaust plume of two Hall thrusters and correlate optical characteristics of oscillating modes with the plasma potential and azimuthal current distribution during those modes. A strong trend was found associating the optical …
Performance Testing Of Various Nozzle Design For Water Electrolysis Thruster, Yuen Liu
Performance Testing Of Various Nozzle Design For Water Electrolysis Thruster, Yuen Liu
Theses and Dissertations
The purpose of this research is to develop new nozzles for the HYDROSTM thruster, a pulsed chemical thruster, to improve the current flight performance. This research consists of a base line test of the factory nozzle, as well as testing of three 15-degree conical nozzles with different expansion ratios. Experiments were conducted at plenum pressures 30, 40, and 45 psia to ensure the thruster is throttleable. Impulse bit data was collected through measuring the impulse response of each firing using a torsional balance thrust stand. Analysis of the thruster performance included calculations of impulse bit, specific impulse, thrust coefficient, …