Engineering Commons^™

A Detailed Uncertainty Analysis Of Heat Transfer Experiments Using Temperature Sensitive Paint, Anish Prasad

Doctoral Dissertations and Master's Theses

Heat transfer experiments for different cooling techniques for a gas turbine blade are performed and the data are collected via temperature sensitive paint, ammeter, thermocouple and manometer measurement techniques. These data are subjected to uncertainty analysis and the major contributing parameter in the uncertainty is found. A tool to identify the major contributing parameter is devised to reduce the uncertainty in the experiment. Further the effect of temperature difference (surface temperature to bulk temperature) is studied to determine the impact on uncertainty and to determine its importance. The analysis between various implementations of the student’s t distribution are conducted to …

Laboratory Development Of A Self-Powered Fontan For Treatment Of Congenital Heart Disease, Arka Das

Doctoral Dissertations and Master's Theses

Around 8% of all newborns with a Congenital Heart Defect (CHD) have only a single functioning ventricle. The Fontan operation has served as a palliation for this anomaly for decades, but the surgery entails multiple complications and survival rate is less than 50% by adulthood. A rapidly testable novel alternative is proposed by creating a bifurcating graft, or Injection Jet Shunt (IJS), used to “entrain” the pulmonary flow and thus provide assistance while reducing the caval pressure. A benchtop Mock Flow Loop (MFL) is configured to validate this hypothesis. The MFL is based on a Lumped-Parameter Model (LPM) of the …

Coupled Fluid-Structure Interaction Modeling Of A Parafoil, Brandon Burnett

Doctoral Dissertations and Master's Theses

In the summer of 2014, Performance Designs, Inc. contacted Embry-Riddle Aeronautical University’s Eagle Flight Research Center to lead an investigation on square parachute design and optimization using modern computational methods to reduce costs in experimental testing. This thesis investigates the foundation for using an implicit fluid-structure interaction computational model to tackle the challenges of modeling a highly-flexible, porous fabric for design optimization of a parafoil parachute’s transient performance. Canopy deformations of a single-cell square parafoil using a fluid-structure interaction (FSI) model with nonlinear material modeling is compared to an experimental setup of matching geometry. The results of this thesis yielded …

More Electric Systems Architecture Effect On Business Jet Performance, Kelsey M. Mazur

Doctoral Dissertations and Master's Theses

A more-electric systems architecture, using current state of the art components, is proposed for the business jet Dassault Falcon 2000. A model of the existing aircraft, both of its overall flying characteristics and performance and of its detail systems layout, is created using Pacelab APDc and SysArcc programs. The model is validated with respect to the aircraft published data. Then, another model of the same aircraft is created but, this time, it is for the aircraft with the new architecture and their respective performance is compared. In particular, this results in changes in mission range and the overall system's weight. …

Effect Of Slot Span On Wing Performance, Juan F. Granizo

Doctoral Dissertations and Master's Theses

This report presents new numerically-derived correlations to estimate the aerodynamic properties of a three-dimensional wing that features a partial to full span fixed slot. Fixed slots have been thoroughly studied in the past with regards to their operation and the relation between slot geometry and wing performance. There have also been many studies on the advantages and disadvantages of tip-slotted wings and the comparison between these and full-slotted wings. Up to this point however, a study on the effects of slot span on wing performance has not been performed. Effect of slot span on wing performance is evaluated in an …

Development Of Fault Tolerant Adaptive Control Laws For Aerospace Systems, Andres E. Perez Rocha

Doctoral Dissertations and Master's Theses

The main topic of this dissertation is the design, development and implementation of intelligent adaptive control techniques designed to maintain healthy performance of aerospace systems subjected to malfunctions, external parameter changes and/or unmodeled dynamics. The dissertation is focused on the development of novel adaptive control configurations that rely on non-linear functions that appear in the immune system of living organisms as main source of adaptation. One of the main goals of this dissertation is to demonstrate that these novel adaptive control architectures are able to improve overall performance and protect the system while reducing control effort and maintaining adequate operation …

Windshield Defrost And Deice Using Carbon Nanotube Composite, Santhosh Kumar Loganathan

Doctoral Dissertations and Master's Theses

Carbon nanotubes (CNT) are well known for their high thermal and electrical conductivities and can offer a great advantage by converting the applied electrical energy into instant heat with minimum energy loss. The goal of this research is to develop a very thin CNT layer sandwiched between two layers of glass substrate in order to generate instant heat through electrodes. The thin CNT layer is fabricated using the CNTRENETM solution, which is a mixture of single-walled nanotubes (SWNTs) (~75%), double-walled nanotubes (DWNTs), and multi-walled nanotubes (MWNTs) with an average CNT length of ~0.4 - 0.6 μm. The thin layer is …

Effect Of Flow-Acoustic Resonant Interactions On Aerodynamic Response Of Transitional Airfoils, Joseph Hayden

Doctoral Dissertations and Master's Theses

A high-accuracy numerical study is conducted to examine the impact of flow-acoustic resonant interactions on the aerodynamic response of symmetric and cambered airfoils in the realistic transitional flow regimes with Rec=140,000 and M=0.0465 as well as the low Reynolds number flow regime with Rec=10,000 and M=0.2. The symmetric NACA-0012 and the cambered SD7003 airfoils are investigated at various angles of attack that have been found previously to include both the tone and no-tone producing regimes, with specific focus on the aerodynamic lift response. Additional simulations are conducted with a low-intensity synthetic turbulence introduced upstream of the airfoils in order to …

Development, Characterization, & Implementation Of Phase-Change Material Cold Plates For Hybrid-Electric Vehicle Battery Systems, Kevin Cwiok

Doctoral Dissertations and Master's Theses

Due to the regulations on internal combustion engine vehicles, there is a large demand of hybrid and electric vehicles with large battery packs as Energy Storage Systems (ESS) capable of long ranges and decreased emissions. These battery packs output large heat loads during charge-depletion mode and currently require active cooling to keep the batteries within operating conditions. The current systems relied onto achieve this are the air and liquid cooled thermal managements systems. A recent alternative approach to current cooling for ESS thermal management is the use of phase-change materials (PCMs). PCMs regulate the temperature of the ESS by leveraging …

Application Of Floating Pedal Regenerative Braking For A Rear-Wheel-Drive Parallel-Series Plug-In Hybrid Electric Vehicle With An Automatic Transmission, Dylan Lewis Lewton

Doctoral Dissertations and Master's Theses

As the world continues to move further away from our reliance on fossil fuels, hybrid vehicles are becoming ever more popular. Braking is a system on both hybrid and normal vehicles that involves a significant amount of power and energy. A hybrid can recapture some of that energy using regenerative braking. In this thesis, a method is devised to blend hydraulic and regenerative braking in the most effective manner. A MATLAB Simulink model was built to simulate a parallel-series plug-in hybrid electric vehicle. The model allows for the implementation of a regenerative brake controller that utilizes floating pedal regen, custom …

Turbulence Control In Wall Jets, Jonathan Latim

Doctoral Dissertations and Master's Theses

The turbulent boundary layer has been the focus of many studies over the last century or so due to its engineering significance. Recent studies have shown that the turbulent boundary layer encapsulates extremely energetic large-scale structures which play a much more significant role in its dynamics than has been previously thought. Further, these large scales amplitude and frequency modulate the finer scales of turbulence. This offers a path to control wall turbulence by controlling the large-scales of the flow. The focus of this thesis is to establish ways to manipulate the energy of the large-scale structures in a model turbulent …

Model Predictive Control Of A Nonlinear Aeroelastic System Using Volterra Series Representations, Wai Leuk Law

Doctoral Dissertations and Master's Theses

The purpose of this study is to investigate the potential effectiveness of using a Volterra-based Model Predictive Control strategy to control a nonlinear aeroelastic system. Model Predictive Control (MPC), also known as Receding Horizon Control (RHC), entails computing optimal control inputs over a finite time horizon, applying a portion of the computed optimal control sequence, and then repeating the process over the next time horizon. The Volterra series provides input-output models of a dynamical system in terms of a series of integral operators of increasing order, where the first-order Volterra operator models the linear dynamics and the higher-order operators model …

Traction And Launch Control For A Rear-Wheel-Drive Parallel-Series Plug-In Hybrid Electric Vehicle, Adam Michael Szechy

Doctoral Dissertations and Master's Theses

Hybrid vehicles are becoming the future of automobiles leading into the all-electric generation of vehicles. Electric vehicles come with a great increase in torque at lower RPM resulting in the issue of transferring this torque to the ground effectively. In this thesis, a method is presented for limiting wheel slip and targeting the ideal slip ratio for dry asphalt and low friction surfaces at every given time step. A launch control system is developed to further reduce wheel slip on initial acceleration from standstill furthering acceleration rates to sixty miles per hour. A MATLAB Simulink model was built of the …

Configuration Validation Of A Novel In-Space Propellant Storage And Transfer System, Priyadarshan Sundararaju

Doctoral Dissertations and Master's Theses

The concept of developing a new technology for on-orbit storage and refueling system has been a great interest among scientists for many decades. This study is about Centaur-based on-orbit propellant storage and transfer. This system takes the advantage of rotational settling to a simple fluid management (FM) system. Specifically, enabling settled fluid transfer and settled pressure control between two tanks. This thesis work focuses on configuration and validation of static and dynamic stability, mass gauging and CFD analysis of the rotational propellant transfer method in space. The application of this technology in Low Earth Orbit (LEO) and Geo-Synchronous Orbit (GEO) …

Performance Characterization Of Ceramic Matrix Composites Through Uniaxial Monotonic Tensile Testing, Jóhannes Pétursson

Doctoral Dissertations and Master's Theses

Ceramic matrix composite (CMC) samples were tested in order to characterize their mechanical performance and provide metrics for material process refinement and component design. Monotonic, uniaxial tensile testing of an uncoated carbon fiber reinforced silicon carbide ceramic at room temperature was performed following ASTM standard C1275 to measure ultimate tensile strength and elastic modulus. Equipment verification was carried out through alignment measurement with a gaged tensile specimen using ASTM E1012 to ensure the monotonic nature of the testing equipment. Tensile strength data was treated with Weibull statistical models to produce A and B-basis strength properties for design values.

An alternative …

A Computer Program For The Coupled Implementation Of Meanline And Throughflow Methods To Simplify The Aerodynamic Design Of Multistage Axial Compressors, Alexander V. Rozendaal

Doctoral Dissertations and Master's Theses

A computer program capable of simplifying the preliminary aerodynamic design process of multistage axial compressors has been developed. This interactive design tool, named C-STAAC, combines the Meanline and Throughflow analysis capabilities of two independent compressor design codes to form one standalone system. The program greatly improves the efficiency of the Preliminary-to-Throughflow stages of compressor design by providing fully coupled interaction between the two platforms. The result enables the user to produce stacked airfoil geometry from only a handful of initial input parameters.

The program additionally offers a wide selection of pre- and post-processing capabilities that were not previously available with …

Automotive-Inspired Inceptors And Control Laws Designed For Simplified Piloted Flight, Kashif Ali

Doctoral Dissertations and Master's Theses

This thesis details the development of a simulator-based experiment in automotive- inspired controls for aircraft. The goal is to fuse the ease of drivability of a car with the flight of an aircraft. A standard automotive control hardware setup coupled with fly-by-wire control laws will allow non-pilots to fly a plane using their familiarity with driving a car. A mathematical description of the control law logic and controller implementation is presented and the human subjects' performance is measured from data collected during experimental testing of the simulator. Preliminary results indicate that non-pilots improve their path-tracking performance and reduce control activity …

Investigation Of Communication Constraints In Distributed Multi-Agent Systems, Zhaoyang Fu

Doctoral Dissertations and Master's Theses

Based on a simple flocking model with collision avoidance, a set of investigations of multi-agent system communication constraints have been conducted, including distributed estimation of global features, the influence of jamming, and communication performance optimization. In flocking control, it is necessary to achieve a common velocity among agents and maintain a safe distance between neighboring agents. The local information among agents is exchanged in a distributed fashion to help achieve velocity consensus. A distributed estimation algorithm was recently proposed to estimate the group’s global features based on achieving consensus among agents’ local estimations of such global features. To reduce the …

Study Of Surface Tension, Natural Evaporation, And Subcooled Boiling Evaporation Of Aqueous Surfactant Solutions, Matthew John Lehman

Doctoral Dissertations and Master's Theses

The relation between surface tension and surfactant concentration and its effect on solution evaporation under natural convection and subcooled pool boiling is examined through experimental methods. Aqueous solutions of sodium lauryl sulfate (SLS), ECOSURFTM EH-14, and ECOSURFTM SA-9 are used in this study. SLS is an anionic surfactant while EH-14 and SA-9 are environmentally-friendly nonionic surfactants.

Surfactants, surface active agents, are known to affect evaporation performance of solutions and are studied in relation to water loss prevention and heat dissipation. Surfactants could be useful under drought conditions which present challenges to water management on a yearly basis in arid areas …

Safety Assurance Of Non-Deterministic Flight Controllers In Aircraft Applications, Alfonso Noriega

Doctoral Dissertations and Master's Theses

Loss of control is a serious problem in aviation that primarily affects General Aviation. Technological advancements can help mitigate the problem, but the FAA certification process makes certain solutions economically unfeasible. This investigation presents the design of a generic adaptive autopilot that could potentially lead to a single certification for use in several makes and models of aircraft. The autopilot consists of a conventional controller connected in series with a robust direct adaptive model reference controller. In this architecture, the conventional controller is tuned once to provide outer-loop guidance and navigation to a reference model. The adaptive controller makes unknown …

Heat Transfer Analysis Of An Oblique Jet Impingement Cooling On Cmc Rough Surface, Karthik Krishna

Doctoral Dissertations and Master's Theses

A Ceramic Matrix Composite is high strength and high temperature capability composite, utilized in components like heat shield of space vehicles, flame holders and disc brakes. To be used in both static and dynamic components of a future gas turbine engine and even with high temperature capabilities of these CMC components, convection cooling will still likely be required. The surface of the CMC varies significantly from traditional super-alloy used in a modern engine, with large level of roughness and significant three-dimensional waviness. These complex features will impact the behavior of the near wall flows, and affect the heat transfer rates …

Detecting Delamination In Carbon Fiber Composites Using Piezoresistive Nanocomposites, Sandeep Chava

Doctoral Dissertations and Master's Theses

Carbon fiber prepreg composites are utilized successfully as structural materials for different lightweight aerospace applications. Delamination is a critical failure mode in these composite materials. As composite plies separate from each other, the composite loses some of its ability for supporting expected loads. Therefore, detection of delamination at right time is a foremost significance. This study presents a new way for detecting delamination in composite plates using piezoresistive nanocomposites. This new procedure is setup and studied through both experimental and computational investigations. In this research, nanocomposites with 5% coarse graphene platelets are fabricated for detecting delamination. 8-ply carbon fiber prepreg …

Vision-Aided Navigation For Autonomous Vehicles Using Tracked Feature Points, Ahmed Saber Soliman Sayem

Doctoral Dissertations and Master's Theses

This thesis discusses the evaluation, implementation, and testing of several navigation algorithms and feature extraction algorithms using an inertial measurement unit (IMU) and an image capture device (camera) mounted on a ground robot and a quadrotor UAV. The vision-aided navigation algorithms are implemented on data-collected from sensors on an unmanned ground vehicle and a quadrotor, and the results are validated by comparison with GPS data. The thesis investigates sensor fusion techniques for integrating measured IMU data with information extracted from image processing algorithms in order to provide accurate vehicle state estimation. This image-based information takes the forms of features, such …

The Effects Of Is-Bao Implementation And Leadership Performance On Safety Culture In Business Aviation Flight Operations, Christopher Mark Broyhill

Doctoral Dissertations and Master's Theses

The International Standard, Business Aircraft Operations (IS-BAO), with a Safety Management System (SMS) as its core element, has been widely accepted by both the International Civil Aviation Organization (ICAO) and the business aviation industry as the mechanism to create a healthy safety culture among the business aviation operators who have implemented the standard. Scholarly literature, however, has presented leadership as the most important factor in the creation and management of a healthy safety culture in organizations in general and aviation organizations in particular. This study examined and compared the effects of IS-BAO progression and leadership performance on the perceptions of …

Predicting General Aviation Pilots’ Weather-Related Performance Through A Scenario-Based Written Assessment, Jessica Cruit

Doctoral Dissertations and Master's Theses

Weather-related accidents continue to challenge the general aviation community and with the development of advanced weather technology, GA pilots need additional education and training on how to effectively use these weather products to ensure flight safety. Currently, the literature on aviation weather suggests that there is a gap in both training and assessment strategy for GA pilots. Furthermore, several studies suggest that there needs to be more assessment of weather-related scenario/application questions for the private pilot’s written knowledge exam in order to assess a deeper level of knowledge for weather-related material. The purpose of this study is to design a …

The Effect Of Generation On Retention Of Women Engineers In Aerospace And Industry, Kristine Maria Kiernan

Doctoral Dissertations and Master's Theses

The purpose of this dissertation was to determine the nature and extent of differences between generational cohorts regarding the effect of family factors on retention of women in engineering, with an emphasis on women in the aerospace industry. While 6% of the aerospace workforce is made up of aeronautical engineers, an additional 11.2% of the aerospace workforce is drawn from other engineering disciplines. Therefore, the analysis included all engineering sub-disciplines. In order to include women who had left the workforce, women in all industries were used as a proxy for women in aerospace.

Exits to other fields were modeled separately …

The Effects Of Safety Culture And Ethical Leadership On Safety Performance, Kevin O’Leary

Doctoral Dissertations and Master's Theses

This dissertation investigated the effects of safety culture and ethical leadership on safety performance in Fractional jet pilots in the United States. The primary objective was to develop a well-fitted model linking these constructs. A composite survey instrument was developed from instruments previously validated in the literature.

There were 305 complete and valid responses from Fractional pilots. The hypothesized factor structure consisted of seven factors. The exogenous factor of safety culture was made up of four sub-factors. The endogenous factors included ethical leadership, pilot commitment, and safety performance. Safety performance was a second order factor consisting of errors and attitudes …

Psychological Health Outcomes Within Usaf Remotely Piloted Aircraft Support Career Fields, Kris Anthony Ostrowski

Doctoral Dissertations and Master's Theses

Remotely piloted aircraft are now commonplace in modern warfare. Enlisted intelligence personnel in the U.S. Air Force (USAF) who support these activities have reported personal accounts of posttraumatic stress and fatigue, possibly due to viewing high-definition, full-motion-video, remote warfare. Rates of mental health diagnoses and counseling are unknown in this population. Incidence rates of 12 specific mental health outcomes were calculated for all enlisted active duty USAF Intelligence Specialists in the 1N1 and 1N0 career fields from 1 January 2006 through 31 December 2010, while considering various demographic and military variables. The incidence rates were compared to RPA sensor operators …

Uav As A Service: Providing On-Demand Access And On-The-Fly Retasking Of Multi-Tenant Uavs Using Cloud Services, Justin Yapp

Doctoral Dissertations and Master's Theses

As commercial roles for Unmanned Aerial Vehicles (UAVs) become more well-defined and demand for the services provided by them increases, UAVs rely more on new cloud computing services and co-operative coordination to provide mission planning, control, tracking and data processing. We present UAV as a Service (UAVaaS) framework, which brings features commonly found in traditional cloud services, such as Infrastructure, Platform, and Software as a Service, to the domain of UAVs. Our work aims to conceptualize and design UAVaaS for commercial applications. Specifically, a cloud-provided orchestration framework that allows multi-tenant UAVs to easily serve multiple heterogenous clients at once and …

Prediction Of Tonal Acoustic Radiation Due To Feedback-Loop Resonant Interactions In Transitional Airfoils, Seyyed Saman Salehian

Doctoral Dissertations and Master's Theses

The objective to this work is to employ the surface integral methods to study the far-field noise propagation from the flow acoustic resonant interactions of the transitional airfoil. The Potential-Theoretic Method (PTM) as an advancement to traditional Kirchhoff methods is presented. The PTM eliminated the need to calculate the normal derivatives of pressure and an arbitrary Kirchhoff surface can be employed. The numerical procedure to implement the PTM is fairly simple. The formulation and physical assumptions of the approach is reviewed, and the numerical procedure is implemented. Furthermore, the two dimensional formulation of the Ffowcs Williams - Hawkings (FW-H) equation …