Digital Commons Network^™

Nuclear Thermal Rocket Engine With A Toroidal Aerospike Nozzle, Kyle Stewart

Master's Theses

This thesis describes the coupling of a nuclear thermal rocket engine with a toroidal aerospike nozzle. The coupling of the two systems consists of two phases. The first of these phases begin with top-level systems and subsystems analysis and design of the new engine. The second phase is the analysis and characterization of the major engine systems through the use of computational fluid dynamics analysis. With the coupling of the nuclear thermal rocket engine with the aerospike nozzle, the new system will be known as the Nuclear Thermal Propulsion System. Due to the uniqueness of coupling a nuclear thermal rocket …

Simulated Annealing-Based Optimal Proportional-Integral-Derivative (Pid) Controller Design: A Case Study On Nonlinear Quadcopter Dynamics, Kristofer Kevin Nemirsky

Master's Theses

In this thesis, the history and evolution of rotor aircraft with simulated annealing-based PID application were reviewed and quadcopter dynamics are presented. The dynamics of a quadcopter were then modeled, analyzed, and linearized. A cascaded loop architecture with PID controllers was used to stabilize the plant dynamics, which was improved upon through the application of simulated annealing (SA). A Simulink model was developed to test the controllers and verify the functionality of the proposed control system design. In addition, the data that the Simulink model provided were compared with flight data to present the validity of derived dynamics as a …

A Parallel Processing And Diversified-Hidden-Gene-Based Genetic Algorithm Framework For Fuel-Optimal Trajectory Design For Interplanetary Spacecraft Missions, Dhathri Harsha Somavarapu

Master's Theses

This thesis proposes a new parallel computing genetic algorithm framework for designing fuel-optimal trajectories for interplanetary spacecraft missions. The framework can capture the deep search space of the problem with the use of a fixed chromosome structure and hidden-genes concept, can explore the diverse set of candidate solutions with the use of the adaptive and twin-space crowding techniques and, can execute on any high-performance computing (HPC) platform with the adoption of the portable message passing interface (MPI) standard. The algorithm is implemented in C++ with the use of the MPICH implementation of the MPI standard. The algorithm uses a patched-conic …

A Study Of Laser Ablation Propulsion Using Polyoxymethelyne And A High Power Diode Laser, Michael David Kolesar

Master's Theses

With an increased interest by universities, government and commercial groups in using constellations of pico and and nano satellites, the need for micro-thrusters to aid in the station-keeping capabilities has become strong. This report examines using polymers and a laser to ablate material as a potential propulsion option for station-keeping. Homopolymer polyoxymethelyne (POM), commonly known as Delrin™, was tested as a fuel for a high powered (20 Watt 980 nm) solid state diode laser ablation thruster to be used for station-keeping on pico and nano sized satellites. The experiments required a partial vacuum to reduce the effects of air decomposition …

Design Of An Attitude Control System For Spin-Axis Control Of A 3u Cubesat, Alexander Joseph Westfall

Master's Theses

This paper describes the design process of developing a spin-axis control system for a 3U CubeSat, a relatively small satellite. Design requires the CubeSat to de-spin after deployment and direct its antenna to track Earth nadir position. The one degree of freedom controller is developed for the TechEdSat, which is a CubeSat with a payload that allows for the assumption that rotation pitch and yaw rates are sufficiently close to zero. Satellite torqueing disturbances are modeled with reaction wheel noise for a more complete system analysis. Sensor noise is unmodeled. Frequency domain and time domain analyses are presented; the entire …

Utilization Of Differential Thrust For Lateral/Directional Stability Of A Commercial Aircraft With A Damaged Vertical Stabilizer, Long Lu

Master's Theses

This thesis investigates the utilization of differential thrust to help a

commercial aircraft with a damaged vertical stabilizer regain its lateral/directional

stability. In the event of an aircraft losing its vertical stabilizer, the consequential

loss of the lateral/directional stability is likely to cause a fatal crash. In this thesis,

the damaged aircraft model is constructed, and the lateral/directional dynamic

stability and frequency domain analyses are conducted. The propulsion dynamics of

the aircraft are modeled as a system of differential equations with engine time

constant and time delay terms to study the engine response time with respect to a

differential thrust …

Prediction Of Residual Stress And Distortion From Residual Stress In Heat Treated And Machined Aluminum Parts, Robert Michael Jones

Master's Theses

Parts machined from relatively large thickness cross sections can experience significant deformations from high residual stresses that develop in the part during the heat treatment used to form the aluminum alloy. Uphill quenching is a process that can create a part with low residual stress and stable dimensions when the process is controlled properly. The uphill quenching process involves a solution heat treat, quench, cool to liquid nitrogen, steam blast, and then age to final temper.

In this thesis two parts were modeled using ANSYS. The first part underwent the uphill quench process in the rough machined state. The second …

Titan I Propulsion System Modeling And Possible Performance Improvements, Oreste Giusti

Master's Theses

This thesis features the Titan I propulsion systems and offers data-supported suggestions for improvements to increase performance. The original propulsion systems were modeled both graphically in CAD and via equations. Due to the limited availability of published information, it was necessary to create a more detailed, secondary set of models. Various engineering equations--pertinent to rocket engine design--were implemented in order to generate the desired extra detail. This study describes how these new models were then imported into the ESI CFD Suite. Various parameters are applied to these imported models as inputs that include, for example, bi-propellant combinations, pressure, temperatures, and …

Thermal Modeling Of Nanosat, Dai Dinh

Master's Theses

Miniaturization of electronic components enabled small scale satellite projects, such as the CubeSat, to be used for scientific research in space. Recently a team of undergraduate and graduate students at San Jose State University (SJSU) had the opportunity to collaborate on designing and building a miniature size CubeSat with the dimensions of 10x10x10 cm3. Although the integration of compact electronics allowed sophisticated scientific experiments and missions to be carried out in space, the thermal control options for such small spacecraft were limited. For example, due to the CubeSat's small size there was no room for dedicated a radiator or insulation …

Design Of A 4-Seat, General Aviation, Electric Aircraft, Arvindhakshan Rajagopalan Srilatha

Master's Theses

Range and payload of current electric aircraft is limited primarily due to low energy density of batteries. However, recent advances in battery technology promise storage of more than 1 kWh of energy per kilogram of weight in the near future. This kind of energy storage makes possible the design of an electric aircraft comparable to, if not better than existing state-of-the art general aviation aircraft powered by internal combustion engines. This thesis explores through parametric studies the effect of lift-to-drag ratio, flight speed, and cruise altitude on required thrust power and battery energy and presents the conceptual and preliminary design …

Non-Homogeneous Hybrid Rocket Fuel For Enhanced Regression Rates Utilizing Partial Entrainment, Kenny Michael Boronowsky

Master's Theses

A concept was developed and tested to enhance the performance and regression rate of hydroxyl terminated polybutadiene (HTPB), a commonly used hybrid rocket fuel. By adding small nodules of paraffin into the HTPB fuel, a non-homogeneous mixture was created resulting in increased regression rates. The goal was to develop a fuel with a simplified single core geometry and a tailorable regression rate. The new fuel would benefit from the structural stability of HTPB yet not suffer from the large void fraction representative of typical HTPB core geometries.

Regression rates were compared between traditional HTPB single core grains, 85% HTPB mixed …

Numerical Investigation Of Fundamental Physics For Flows Over Expansion And Compression Corners, Freddy Ngo

Master's Theses

Oblique shocks and expansion waves are commonly found in aerospace applications such as wings and nozzles. These types of shocks change the properties of the flow, thus causing changes in the lift, drag, and/or heat transfer. Hypersonic flow is important to study as its impacts are significant. In this thesis, computational fluid dynamics (CFD) is utilized to characterize the physics of the flow. Parametric studies of the Mach number and turning angle were conducted. Simulations included both inviscid and viscous flows to demonstrate the effects of boundary layer on flow properties. The majority of the viscous flows were focused on …

The Manual Flight Skill Of Airline Pilots, Antonio Puentes

Master's Theses

The manual flight ability of commercial airline pilots has been scrutinized

after several aviation disasters in the first decade of the 21st century where pilot error has been a contributing cause. Voluntary pilot incident reports from the National Aeronautics and Space Administration's Aviation Safety Reporting System (ASRS) were examined as one method to determine the prevalence of manual flight skill decline among airline pilots. The investigation studied reports from unstabilized approach to landings where the pilots manually controlled the aircraft during descent. An analysis of the ASRS reports from pilots flying traditional flight deck aircraft compared with pilots flying aircraft …