Aerospace Engineering Commons^™

Understanding And Minimizing The Effects Of Propellant Mean Bulk Temperature Changes In Solid Rocket Motors, Thomas Sorensen

Student Research Symposium

Solid rocket propellant typically contains the geometry of an extruded annulus. This propellant, when ignited, burns radially at a rate called the “burn rate”. This rate dramatically affects important motor performance characteristics such as pressure, thrust, and specific impulse. Each different mixture of solid rocket propellant has a sensitivity to initial propellant temperature. The relationship between burn rate and initial temperature sensitivity function are each determined experimentally. This literature review will analyze existing experimental data. The objective of the research is to see if there is a reliable way to predict the burning rate’s temperature sensitivity prior to obtaining new …

Controlling Oxidizer-Fuel Ratio With Vortex Injection In Hybrid Rockets, Max Francom

Student Research Symposium

Hybrid motors have existed as a hypothetical propulsion system for decades in a wide range of upper stage rocket motors due to their simple, robust, non-toxic, and versatile nature. However, inherent to hybrids is oxidizer:Fuel ratio (O:F Ratio) shift over time, the elimination of which would remove many potential barriers to hybrid rocket motor usage in most spaceflight applications. The most important and difficult part of analytical models of hybrid rockets is the regression/combustion rate of hybrid fuel. O:F Ratio control is fully dependent on the ability to manipulate this regression independently of Oxidizer mass input. One potential method of …

In-Situ Optical Measurements Of Combustion Plumes, Cara Frischkorn

Student Research Symposium

The exhaust plumes of rocket and jet propulsion systems feature highly-oxidizing, potentially corrosive, extremely high temperature flows. The hostility of these environments makes obtaining in-situ thermal flow measurements extremely difficult. The conventional method for these measurements uses Gardon heat-flux gauges requiring complex and highly invasive installations which cannot be used for flight applications. More recent work has used fiberoptic cable installations to sense internal flow conditions of hybrid and solid fuel rockets. In this configuration, fiber optic cables inserted through the fuel and into the flow are consumed by the flame as the fuel surfaces pyrolyze, but the cable tips …

Relating Throttled Hybrid Motor Performance To Oxidizer-To-Fuel Ratio, Trevor Coombs

Student Research Symposium

A hybrid rocket motor's ability to throttle and restart, along with other desirable traits, drives its potential to be an emerging technology in spaceflight applications. However, the current lack of an ability to maintain an optimal mixture ratio of oxidizer to fuel propellants, O/F ratio, during combustion limits the hybrid motor's overall efficiency. This study quantifies how variations in O/F ratio and combustion chamber pressure, which a throttle valve can indirectly manipulate upstream of the chamber, affect the characteristic velocity (c * ) and specific impulse (Isp) of the motor. The researcher uses an analytical hybrid rocket combustion model and …

Energy Storage Can Increase The Value And Flexibility Of A Nuclear Power Plant But Makes Plant Economics More Subject To Uncertainty In Electricity Price, Jacob Bryan

Student Research Symposium

Regional electricity markets currently rely heavily on coal and natural gas resources to meet electricity demand. Intermittent renewable resources like wind and solar power are location-dependent and are not dispatchable resources. Flexible nuclear power, achieved through the use of integrated thermal energy storage, may be able to complement these renewable resources to provide clean, predictable power in an evolving electricity grid. This study considers such a flexible nuclear plant and seeks to address a fundamental modeling question: which uncertain model inputs have a significant effect on the economics of the system, and to what degree? These questions are addressed by …

Molecular Dynamics Simulations Of Liquid Crystal Elastomers, Nanang Mahardika

Student Research Symposium

Molecular Dynamics Simulations of Liquid Crystal Elastomers

Filter-Based Air Sampler Capable Of Integration Into Small Unmanned Aerial Vehicles, Robert M. Eninger, Stepanie A. Ohms, Jeremy M. Slagley

AFIT Patents

A filter-based air sampler, more specifically a filter-based air sampler capable of integration into small unmanned aerial systems is disclosed. The filter-based air sampler may include a filter assembly which has as its component parts: an open faced air intake component, a filter, and a filter support that has a central supporting grid. The filter assembly may joined to the housing of a fan, such as a centrifugal fan, with the supporting grid of the filter support being disposed over the air inlet of the fan.

Sharprazor: Automatic Removal Of Hair And Ruler Marks From Dermoscopy Images, Reda Kasmi, Jason Hagerty, Reagan Harris Young, Norsang Lama, Januka Nepal, Jessica Miinch, William V. Stoecker, R. Joe Stanley

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Background: The removal of hair and ruler marks is critical in handcrafted image analysis of dermoscopic skin lesions. No other dermoscopic artifacts cause more problems in segmentation and structure detection. Purpose: The aim of the work is to detect both white and black hair, artifacts and finally inpaint correctly the image. Method: We introduce a new algorithm: SharpRazor, to detect hair and ruler marks and remove them from the image. Our multiple-filter approach detects hairs of varying widths within varying backgrounds, while avoiding detection of vessels and bubbles. The proposed algorithm utilizes grayscale plane modification, hair enhancement, segmentation using tri-directional …

Sustainable Atos - Flying To Net Zero, Eva Maleviti, Bettina Mrusek

Publications

Pathways to Net Zero- Targets

Improve fuel-efficiency by an average of 2% per year - 2020 to 2030

Reduction in total carbon dioxide emissions to net-zero by 2050.

After 2026 carbon allowances will be zero for EU.

Rocketing Ahead: Basketball Player Plans To Apply Mechanical Engineering To Aerospace, Rocky Garza Jr.

Black History at St. Mary's University - 2025 Collection

Student Emmanuel Ewuzie is in a unique position as he is not only a successful athlete on the court, but also a successful student with aspirations in pursuing a career in aerospace engineering. While basketball and aerospace engineering may seem like they might not have many commonalities, Ewuzie can leverage his education and on-the-court experiences to become a successful scholar and leader. Coach Buddy Meyer and Associate Professor Juan Ocampo are among many people who vouch for Ewuzie’s ability to lead by example, while also having the drive to pursue goals that not only lead to personal success but also …

Loss Of Control In-Flight (Loc-I): A Mixed Methods Study Of Voluntary Versus Mandatory Reports From The United States Of America, Roger Lee

Doctoral Dissertations and Master's Theses

Loss of control in flight (LOC-I) is one of modern aviation’s three most prominent fatal accidents. In the United States, air accidents are mandatorily reported to and investigated by the National Transportation Safety Board (NTSB). Established in 1976, the Air Safety Reporting System (ASRS) is a voluntary safety reporting (VSR) system administered by the National Aeronautics and Space Administration (NASA). Over 1.7 million ASRS reports have been processed to date. While the NTSB system handles LOC-I accidents, less severe incidents may have been reported voluntarily through the ASRS.

Safety reporting has been deemed the most valuable activity and the centerpiece …

The Role Of Slip System Activation On Ni-Based Superalloy High Temperature Fatigue, Alexandru Lopazan

Doctoral Dissertations and Master's Theses

Nickel-based superalloys are used extensively in the aviation industry, particularly in aircraft engine components. These materials are desirable due to their high strength, resistance to creep, corrosive environment, and high temperature. It has been well documented that material fatigue is characterized by material microstructure, type of loading, and other parameters. Currently, research into the effects of fatigue on complex materials like nickel-based superalloys is being pursued. Previous research has found that preconditioning of Inconel 718 samples at 700 ℃ with 1.0% strain led to an improved fatigue life. It has been suggested that this could be caused by the activation …

Small Unmanned Aircraft Systems: Operator Workload And Situation Awareness Utilizing First Person View Techniques, Ross Lucas Stephenson Jr

Doctoral Dissertations and Master's Theses

The small, unmanned aircraft systems (sUAS) sector within the aviation industry is experiencing unprecedented growth. However, the regulatory guidance for the safe integration of sUAS into the National Airspace System (NAS) has not kept pace with this technological growth within the market. Current regulatory limitations of line-of-sight operations may have an impact on the establishment of an equivalent level of safety for sUAS operations as maintained by manned aircraft. The focal point of the discussion of line-of-sight operations has been the ability of the sUAS pilot to see and avoid all obstacles and other aircraft in a safe and timely …

A Simulation Of The Impacts Of Climate Change On Civil Aircraft Takeoff Performance, Thomas D. Pellegrin

Doctoral Dissertations and Master's Theses

Climate change affects the near-surface environmental conditions that prevail at airports worldwide. Among these, air density and headwind speed are major determinants of takeoff performance, and their sensitivity to global warming carries potential operational and economic implications for the commercial air transport industry. Previous archival and prospective research observed a weakening in headwind strength and predicted an increase in near-surface temperatures, respectively, resulting in an increase in takeoff distances and weight restrictions. The main purpose of the present study was to update and generalize the extant prospective research using a more representative sample of worldwide airports, a wider range of …

Impact Resistance Of Hybrid Metal-Organic Frameworks/Carbon Fibers Composites, Derek Isaac Espinosa Ramirez

Doctoral Dissertations and Master's Theses

The increase in the use of carbon fiber-reinforced polymers (CFRPs) composites in the aerospace industry generated the need of improving the properties and capabilities of these composites by adding nano-reinforcements to the carbon fibers, also called hybrid fiber reinforced polymer composites. In this study, the energy absorption due to impact at low speed will be tested and simulated in four configurations of CFRPs utilizing the same [0/90]_S layout throughout them.

The carbon fiber configurations used during this study are de-sized, acid-activated, metal-organic frameworks (MOF), and carbon nanotubes (CNTs). Nickel (II) Nitrate, Methylimidazole, and Methanol were used to grow the …

Numerical Modeling Of Synthetic Vortical Disturbance Interactions Using Openfoam, Ahmed Bilal

Doctoral Dissertations and Master's Theses

Nowadays, the number of Advance Air Mobility (AAM) Electic Vertical Take-off and Landing (eVTOL) concepts is rapidly increasing due to their capability of vertical take-off and landing at vertiports located on rooftops of tall urban buildings, which does not require using the ground space in a condensed urban environment. Such flight operations, however, will be greatly affected by the vertiport’s highly unsteady, turbulent flow environment. The goal of this study is to model the turbulent wind interaction with a building to understand the unsteady flow characteristics around vertiports and match the induced unsteady disturbance field to the canonical disturbance forms, …

Nonlinear Dynamics Analysis And Control Of Space Vehicles With Flexible Structures, Marco Fagetti

Doctoral Dissertations and Master's Theses

Space vehicles that implement hardware such as antennas, solar panels, and other extended appendages necessary for their respective missions must consider the nonlinear rotational and vibrational dynamics of these flexible structures. Formulation and analysis of these flexible structures must account for the rigid-flexible coupling present in the system dynamics for stability analysis and control design. The system model is represented by a flexible appendage attached to a central rigid body, where the flexible appendage is modeled as a cantilevered Euler-Bernoulli beam. Discretization techniques, such as the assumed modes method and the finite element method, are used to model the coupled …

The Linearized Euler Equations For Predicting Supersonic Jet Noise Of A Rectangular Jet Using Openfoam, Patrick Good

Doctoral Dissertations and Master's Theses

This thesis presents a Linearized Euler Equation (LEE) solver that was developed for OpenFOAM. OpenFOAM is an open-source Computational Fluid Dynamics (CFD) package that is widely used by industry and academia. The LEE’s are a set of equations used in Computational Aeroacoustics (CAA). The LEE’s can solve for the acoustic solution directly and quickly. The solver developed, named leeFoam, was tested against analytical solutions to verify accuracy and then was utilized to predict the acoustics of a heated supersonic rectangular jet. The rectangular jet (RJET) results were compared against experimental data.

The results from this work show that OpenFOAM can …

Characterization Of Bistability Behavior In Unsymmetric Cfrp Laminates, Evan Medora

Doctoral Dissertations and Master's Theses

Composite laminates of unsymmetric layup families often exhibit twin stable shapes at room temperature, a phenomenon known as bistability. Unsymmetric bistable composite laminates have often been suggested for applications in aerospace morphing structures, damping, and energy storage, because of their ability to easily change their shape while being homogenized with the rest of the composite structure.

This study analyzes the mechanisms responsible for bistability in unsymmetrical [0/0/90/90] laminates through a combination of experiments and modeling. Several unsymmetrical laminates with different aspect ratios were fabricated using autoclave processing. Digital image correlation (DIC) is used to monitor laminate strains in situ during …

Understanding The Structure Of Wing Tip Vortices Of Bio-Inspired Winglets, Greeshma C. Daniel

Doctoral Dissertations and Master's Theses

Bio-inspired wing tip devices were investigated with the goal of improving the fuel efficiency of subsonic aircraft. Particularly, the structure of a bio-inspired winglet design based on bird feathers were tested in a low-speed wind tunnel. Particle image velocimetry (PIV), was used to study the flow field at two planes aft of the wing as the wing tip vortices developed downstream. These were time-dependent, stereoscopic particle image velocimetry (sPIV) measurements carried out at two planes located at 0.7 and 2 chord distances downstream from the wing. The structure of the wingtip vortices was compared and contrasted with that formed over …