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Air Force Institute of Technology

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Articles 2521 - 2550 of 5700

Full-Text Articles in Engineering

Trust Management And Security In Satellite Telecommand Processing, Mark C. Duncan Mar 2011

Trust Management And Security In Satellite Telecommand Processing, Mark C. Duncan

Theses and Dissertations

New standards and initiatives in satellite system architecture are moving the space industry to more open and efficient mission operations. Primarily, these standards allow multiple missions to share standard ground and space based resources to reduce mission development and sustainment costs. With the benefits of these new concepts comes added risk associated with threats to the security of our critical space assets in a contested space and cyberspace domain. As one method to mitigate threats to space missions, this research develops, implements, and tests the Consolidated Trust Management System (CTMS) for satellite flight software. The CTMS architecture was developed using …

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Virtual Battlespace Behavior Generation Through Class Imitation, Bryon K. Fryer Jr. Mar 2011

Virtual Battlespace Behavior Generation Through Class Imitation, Bryon K. Fryer Jr.

Theses and Dissertations

Military organizations need realistic training scenarios to ensure mission readiness. Developing the skills required to differentiate combatants from non-combatants is very important for ensuring the international law of armed conflict is upheld. In Simulated Training Environments, one of the open challenges is to correctly simulate the appearance and behavior of combatant and non-combatant agents in a realistic manner. This thesis outlines the construction of a data driven agent that is capable of imitating the behaviors of the Virtual BattleSpace 2 behavior classes while our agent is configured to advance to a geographically specific goal. The approach and the resulting agent …

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Image Dependent Relative Formation Navigation For Autonomous Aerial Refueling, James M. Howard Mar 2011

Image Dependent Relative Formation Navigation For Autonomous Aerial Refueling, James M. Howard

Theses and Dissertations

This research tests the feasibility, accuracy, and reliability of a predictive rendering and holistic comparison algorithm with use of an optical sensor to provide relative distance and position behind a lead or tanker aircraft. Using an accurate model of a tanker, an algorithm renders image(s) for comparison with actual collected images by a camera installed on the receiver aircraft. Based on this comparison, information used to create the rendered image(s) is used to provide the relative navigation solution required for autonomous air refueling. Given enough predicted images and processing time, this approach should reliably find an accurate solution. Building on …

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Polarimetric Enhancements To Electro-Optical Aided Navigation Techniques, Jeremiah D. Johnson Mar 2011

Polarimetric Enhancements To Electro-Optical Aided Navigation Techniques, Jeremiah D. Johnson

Theses and Dissertations

Navigation in indoor and urban environments by small unmanned systems is a topic of interest for the Air Force. The Advanced Navigation Technology Center at the Air Force Institute of Technology is continually looking for novel approaches to navigation in GPS deprived environments. Inertial sensors have been coupled with image aided concepts, such as feature tracking, with good results. However, feature density in areas with large, flat, smooth surfaces tends to be low. Polarimetric sensors have been used for surface reconstruction, surface characterization and outdoor navigation. This thesis combines aspects of some of these algorithms along with a realistic, micro-facet …

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Optical Metamaterial Design, Fabrication And Test, Jack P. Lombardi Mar 2011

Optical Metamaterial Design, Fabrication And Test, Jack P. Lombardi

Theses and Dissertations

Metamaterials, materials that make use of naturally occurring materials and designed structures to create materials with special properties not found in nature, are a fascinating new area of research, combining the fields of physics, microfabrication, and material science. This work will focus on the development of metamaterials operating in the visible and infrared which will be constructed and tested for basic optical properties. Possible applications for these materials will not be investigated. The this work will go into the fabrication and test of layered metal-dielectric structures, called layered metamaterials, as these structures hold potential for applications in advanced optical systems. …

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Signals Of Opportunity Navigation Using Wi-Fi Signals, Wilfred E. Noel Mar 2011

Signals Of Opportunity Navigation Using Wi-Fi Signals, Wilfred E. Noel

Theses and Dissertations

Since GPS is generally limited to areas with clear sky view, additional methods of navigation are currently being explored. This thesis explores navigation using Signals of Opportunity(SoOP). The signals chosen for evaluation in this thesis are the common Internet IEEE 802.11a/g signals, or Wi-Fi. This thesis presents SoOP navigation based on cross-correlations of received data from multiple Wi-Fi stations. It shows the effectiveness of the methods using collected Wi-Fi signals in a real-world environment. By using simple statistical representations of collected data in large groups, or windows, cross-correlation calculations can produce timing offsets between simulated stations. The timing offsets, or …

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Simultaneous Range/Velocity Detection With An Ultra-Wideband Random Noise Radar Through Fully Digital Cross-Correlation In The Time Domain, James R. Lievsay Mar 2011

Simultaneous Range/Velocity Detection With An Ultra-Wideband Random Noise Radar Through Fully Digital Cross-Correlation In The Time Domain, James R. Lievsay

Theses and Dissertations

This research effort examines the theory, application, and results of applying two-dimensional cross-correlation in the time domain to ultra-wideband (UWB) random noise waveforms for simultaneous range and velocity estimation. When applying common Doppler processing techniques to random noise waveforms for the purpose of velocity estimation, the velocity resolution degrades as the signal bandwidth or the target speed increase. To mitigate the degradation, the Doppler approximation is not utilized, and instead, wideband signal processing theory is applied in the time domain. The results show that by accurately interpolating each sample in the digitized reference signal, a target's velocity and range can …

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Kernelized Locality-Sensitive Hashing For Fast Image Landmark Association, Mark A. Weems Mar 2011

Kernelized Locality-Sensitive Hashing For Fast Image Landmark Association, Mark A. Weems

Theses and Dissertations

As the concept of war has evolved, navigation in urban environments where GPS may be degraded is increasingly becoming more important. Two existing solutions are vision-aided navigation and vision-based Simultaneous Localization and Mapping (SLAM). The problem, however, is that vision-based navigation techniques can require excessive amounts of memory and increased computational complexity resulting in a decrease in speed. This research focuses on techniques to improve such issues by speeding up and optimizing the data association process in vision-based SLAM. Specifically, this work studies the current methods that algorithms use to associate a current robot pose to that of one previously …

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Neutron Detection Using Gadolinium-Based Diodes, Benjamin R. Thomas Mar 2011

Neutron Detection Using Gadolinium-Based Diodes, Benjamin R. Thomas

Theses and Dissertations

P-n heterojunction diodes consisting of a thin n-type layer of Gd2O3 deposited on both p-type Si and p-type 4H SiC substrates were explored as possible solid-state neutron detectors. 79 keV internal conversion electrons from the de-excitation of the meta-stable Gd-158 nucleus can create ionization in the depletion region of the reverse-biased diodes resulting in a detectable signal. The diodes were modeled with Davinci software to determine the feasibility of signal detection above the reverse-bias leakage current. A CASINO simulation showed that less than one percent of the internal conversion electrons deposit their full energy within the achievable …

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Determining Pilot Manning For Bomber Longevity, Jason S. Hamilton Mar 2011

Determining Pilot Manning For Bomber Longevity, Jason S. Hamilton

Theses and Dissertations

In support of US Air Force efforts to conserve resources without sacrificing capability, this research examines the question of whether the 509th Bomb Wing could continue to provide maximum combat capability with fewer assigned pilots. During peacetime, pilot proficiency training comprises the majority of annual flying hours for the small B-2 bomber fleet. Optimal pilot manning will decrease the accumulation of excess wear on the airframes; helping to extend the viable life of the B-2 fleet and preserve the deterrent and combat capabilities that it provides to the United States. The operations and maintenance activity flows for B-2 aircraft and …

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Optimal Ch-47 And C-130 Workload Balance, Dustin P. Jones Mar 2011

Optimal Ch-47 And C-130 Workload Balance, Dustin P. Jones

Theses and Dissertations

The Air Force can save thousands of dollars by reducing the number of blade hours on the CH-47 through finding an optimal mixture of CH-47s and C-130s to conduct current operations in Afghanistan and Iraq. Ultimately these savings will relieve maintenance operations for the CH-47 and lengthen the lifespan of the CH-47 airframe. Moreover, incorporating C-130s into the operations will reduce cargo transit time from supply depots. This study looks at the involvement of the C-130 in CH-47 airlift operations to reduce CH-47 usage and increase supply efficiency. The research focus is narrowed to current airlift operations in Afghanistan and …

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Decision Analysis And Validation Of Value Focused Thinking Decision Models Using Multivariate Analysis Techniques, James L. Pruitt Mar 2011

Decision Analysis And Validation Of Value Focused Thinking Decision Models Using Multivariate Analysis Techniques, James L. Pruitt

Theses and Dissertations

Decision Analysis (DA) is a useful tool to assist decision makers (DM) with difficult and complex decisions using mathematical models. Value Focused Thinking (VFT) models are a useful DA tool widely employed in the Air Force. However, VFT models are rarely validated. This research will attempt to validate any given VFT model and provide insight into the discriminating attributes of the alternative set. First, a two group discriminant analysis is applied the alternative set given the prior knowledge of the selected alternatives. Next, compromise programming is used attempt to minimize the distance between the posterior probability of an alternative being …

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Alternative Active Duty Military Retirement Plan, Amy L. Schmidt Mar 2011

Alternative Active Duty Military Retirement Plan, Amy L. Schmidt

Theses and Dissertations

No abstract provided.

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Determining The Value Of Future Information, James J. Springston Mar 2011

Determining The Value Of Future Information, James J. Springston

Theses and Dissertations

Companies continuously struggle to quantify the value of their information in an attempt to gain a better understanding of the return on investment of their information technology (IT) architecture. One approach companies have taken to place a numeric value on information is to treat it as a traditional economic asset (e.g. equipment, buildings, and vehicles) that is governed by its own unique set of laws. Once an enterprise understands the behavior of information it can incorporate Skyrme's "10 value adding aspects of information" when developing IT architecture, thus maximizing the potential value of their information. Like most enterprises, the Intelligence …

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Fusion Schemes For Ensembles Of Hyperspectral Anomaly Detection Algorithms, Brooks R. Turnquist Mar 2011

Fusion Schemes For Ensembles Of Hyperspectral Anomaly Detection Algorithms, Brooks R. Turnquist

Theses and Dissertations

Hyperspectral imaging is playing an ever increasing role in our military's remote sensing operations. The exponential increase in collection operations generates more data than can be evaluated by analysts unassisted. Anomaly detectors attempt to reduce this load on analysts by identifying potential target pixels which appear anomalous when compared to what are determined to be background, or non-target, pixels. However, there is no one individual algorithm that is best suited for all situations and it can be difficult to choose the best algorithm for each individual task. Fusion techniques have been shown to reduce errors and increase generalization, eliminating the …

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Understanding Schedule Forecasting Shortfalls In Federal Design-Build Facility Procurement, Timothy W. Gannon Mar 2011

Understanding Schedule Forecasting Shortfalls In Federal Design-Build Facility Procurement, Timothy W. Gannon

Theses and Dissertations

This research explores whether initial schedules provide reliable forecasting for project control in federal design build facility procurement. The purpose of this research is to understand how scheduling operates in the Department of Defense environment and identify how project change underscores schedule uncertainty. The research methodology involves a comparative analysis of project schedule data from three case studies. The investigation documents how initial project schedules fail to sufficiently forecast and provide a reliable baseline for total cost, final duration, and activity count for three design-build projects. Most schedule variability occurs after the 100% design benchmark. Furthermore, activity growth highlights the …

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Impact Of Snow Removal Operations On Thermoplastic Pavement Markings, Monica L. Monfette Mar 2011

Impact Of Snow Removal Operations On Thermoplastic Pavement Markings, Monica L. Monfette

Theses and Dissertations

This pilot study explored the effect snow removal operations have on thermoplastic pavement markings. Including snow removal as a separate independent variable is unique because much of the previous research performed on pavement marking degradation mentioned snow removal as a direct cause in a marking degrading more rapidly; however, it is mentioned as an afterthought and a suggestion to be considered in future research. This pilot study looked at 10 thermoplastic markings and all marking data were collected in the field, using a hand-held retroreflectometer. Data collected began 60 days after initial marking application and ended 12 months after initial …

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Paint Pavement Marking Performance Prediction Model That Includes The Impacts Of Snow Removal Operations, Dale M. Mull Mar 2011

Paint Pavement Marking Performance Prediction Model That Includes The Impacts Of Snow Removal Operations, Dale M. Mull

Theses and Dissertations

The results of this research effort were captured in two manuscripts drafted for publication in peer reviewed journals. The first manuscript validated a previously published model with an expanded data set, updated service life predictions for painted pavement markings using recently released pavement marking retroreflectivity minimums, and incorporated recent cost data to evaluate two alternative methods of compliance with the new retroreflectivity minimums for two-lane roads. The second manuscript developed a new performance prediction model for paint pavement markings that includes the impact of snow removal operations and then applied the model to four real-world roadways to determine if replacement …

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A Primary Care Workload Production Model For Estimating Relative Value Unit Output, Rachel G. Murphy Mar 2011

A Primary Care Workload Production Model For Estimating Relative Value Unit Output, Rachel G. Murphy

Theses and Dissertations

Health care costs have grown to unsustainable levels nationally and within the Department of Defense. Military health care costs have historically been difficult to isolate, causing budget cuts to be the vehicle for cost control. Maximum efficiency, therefore, is the goal in order to show improvement. With the Air Force’s new preventive health plan, they aim to drive a long-term posture for cost reduction through prevention. This research effort aimed to develop a tool to assist in future efforts to understand and improve efficiency in workload output, and whether a relationship exists between patient workload demand and the per-encounter variables …

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Measuring The Utility Of A Cyber Incident Mission Impact Assessment (Cimia) Process For Mission Assurance, Christy L. Peterson Mar 2011

Measuring The Utility Of A Cyber Incident Mission Impact Assessment (Cimia) Process For Mission Assurance, Christy L. Peterson

Theses and Dissertations

Information is a critical asset on which virtually all modern organizations depend upon to meet their operational mission objectives. Military organizations, in particular, have embedded Information and Communications Technologies (ICT) into their core mission processes as a means to increase their operational efficiency, exploit automation, improve decision quality, and shorten the kill chain. However, the extreme dependence upon ICT results in an environment where a cyber incident can result in severe mission degradation, or possibly failure, with catastrophic consequences to life, limb, and property. These consequences can be minimized by maintaining real-time situational awareness of mission critical resources so appropriate …

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Modeling Vertical Flow Treatment Wetland Hydraulics To Optimize Treatment Efficiency, David T. Roen Ii Mar 2011

Modeling Vertical Flow Treatment Wetland Hydraulics To Optimize Treatment Efficiency, David T. Roen Ii

Theses and Dissertations

An upward Vertical Flow Treatment Wetland (uVFTW) at Wright Patterson AFB designed to bioremediate contaminated groundwater exhibits hydraulic short-circuiting. Prior studies estimated that groundwater flowed through less than 50% of the wetland’s volume, and that the mean residence time was significantly less than the nominal residence time, which was calculated assuming flow through the entire wetland volume. The objective of this research was to investigate how uVFTW hydraulics affects treatment efficiency, and to propose design strategies to maximize treatment efficiency. A groundwater flow and contaminant transport model of a uVFTW that couples hydraulics and degradation kinetics was built and applied …

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A Systems Architecture And Advanced Sensors Application For Real-Time Aircraft Structural Health Monitoring, Hyoungjin Shin, Edward C. Beckett Mar 2011

A Systems Architecture And Advanced Sensors Application For Real-Time Aircraft Structural Health Monitoring, Hyoungjin Shin, Edward C. Beckett

Theses and Dissertations

Aircraft are being pushed beyond their original service life, increasing the potential for structural failures. A catastrophic in flight failure of an F-15 bulkhead and severe cracking in the C-130 Wing rainbow fitting are two recent examples that have caused major problems for the Air Force. Previous Aircraft Structural Health Monitoring Systems research primarily explored using a system during the ground maintenance phase. This research will explore a Real-Time Aircraft Structural Health Monitoring System (RTASHMS) that includes a ground phase as well as an in-flight phase. The RTASHMS will continuously analyze structural hot spots, detect critical structural damage or cracks …

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Architecture Based Workload Analysis Of Uas Multi-Aircraft Control: Implications Of Implementation On Mq-1b Predator, Jason D. Mcgrogan, Michael F. Schneider Mar 2011

Architecture Based Workload Analysis Of Uas Multi-Aircraft Control: Implications Of Implementation On Mq-1b Predator, Jason D. Mcgrogan, Michael F. Schneider

Theses and Dissertations

An increased demand for use of Unmanned Aircraft Systems (UASs) without commensurate increases in pilot manpower has prompted proposals for simultaneous control of multiple aircraft by a single pilot or Multi-Aircraft Control (MAC). To understand the potential effects of MAC, an IMPRINT Pro, Multi-Resource Theory, pilot workload model was developed from pedigreed system architecture. Feedback from active UAS pilots was used to validate the model and establish a workload saturation threshold value of 60, above which pilots may experience performance degradation over extended periods of time. The model predicts that pilots experience low workload when operating one or two UASs …

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Performance Characterization Of A Novel Plasma Thruster To Provide A Revolutionary Operationally Responsive Space Capability With Micro- And Nano-Satellites, John-David C. De La Harpe Mar 2011

Performance Characterization Of A Novel Plasma Thruster To Provide A Revolutionary Operationally Responsive Space Capability With Micro- And Nano-Satellites, John-David C. De La Harpe

Theses and Dissertations

Few options currently exist to provide propulsion for extremely small satellites due to design constraints on power, volume, and weight. However, future operation will require a capability to conduct orbital maneuvers, momentum dumping, and precision pointing for these low cost satellites. The research presented here represents the first effort to operate and quantify the performance of a new micro plasma thruster design which provides a novel solution to these disparate competing constraints. The thruster in this study represents a deviation from traditional circular Hall thruster design practices, because it eschews a central magnetic circuit, which results in nearly parallel electric …

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Effects Of Air Drag And Lunar Third-Body Perturbations On Motion Near A Reference Kam Torus, Luke J. Hagen Mar 2011

Effects Of Air Drag And Lunar Third-Body Perturbations On Motion Near A Reference Kam Torus, Luke J. Hagen

Theses and Dissertations

The KAM Theory was developed in the 1960s but only in the last decade has it been applied to Earth orbiting satellites. Physical state variables of position and velocity are transformed into KAM Torus variables. The KAM Torus is a geometrical structure similar to that of a multi-dimensional donut. The Earth satellite's motion can be described as traversing the surface of this donut. There are two primary advantages of this transformation: (1) The new generalized coordinates which are analogous with mean anomaly, right ascension of the ascending node, and argument of perigee, increment linearly with time, and (2) Perturbations due …

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Osculating Relative Orbit Elements Resulting From Chief Eccentricity And J2 Perturbing Forces, Joshuah A. Hess Mar 2011

Osculating Relative Orbit Elements Resulting From Chief Eccentricity And J2 Perturbing Forces, Joshuah A. Hess

Theses and Dissertations

Relative orbit elements (ROEs) based on a circular chief satellite orbit are erroneous when applied to a perturbed,non-circular reference orbit. In those situations, the ROEs will encounter geometric instability and drift. To counter this, a set of time-variant ROEs have been derived to describe the relative orbit for both the unperturbed, elliptical chief, and the perturbed, circular chief. A highly coupled relationship is found that describes the relative trajectory to higher accuracy when compared to numerical integration. To show the applicability of the ROEs to formation design, methods to initialize a stationary relative orbit are detailed and an algorithm for …

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Optimized Dual Expander Aerospike Rocket, Joshua N. Hall Mar 2011

Optimized Dual Expander Aerospike Rocket, Joshua N. Hall

Theses and Dissertations

Research at the Air Force Institute of Technology (AFIT) focused on designing a cryogenic dual-expander aerospike nozzle (DEAN) upper stage rocket engine to produce 50,000 pounds-force (222.4 kilo-Newtons) vacuum thrust, 464 seconds of vacuum specific impulse and a thrust-to-weight ratio of 106.5. The use of dual expander cycles improves engine reliability, maximizes efficiency, and eliminates some catastrophic failure modes. An upper stage engine with an aerospike nozzle is shorter and lighter than an equivalent performing conventional bell nozzle upper stage engine. Previous research focused on first developing a feasible closed DEAN design model and secondly expanding the model to support …

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Fixed-Wing Aircraft Combat Survivability Analysis For Operation Enduring Freedom And Operation Iraqi Freedom, Christopher L. Jerome Mar 2011

Fixed-Wing Aircraft Combat Survivability Analysis For Operation Enduring Freedom And Operation Iraqi Freedom, Christopher L. Jerome

Theses and Dissertations

The primary tenet of the aircraft survivability discipline is threat definition. In order to deliver relevant capabilities and protection to the warfighter it is imperative; therefore, to provide timely, accurate, and actionable threat data to the survivability community. In an attempt to identify the evolution of aircraft threats in today's combat environment, an analysis of fixed-wing aircraft battle damage was conducted. This analysis reports battle damage incidents from OPERATIONS ENDURING FREEDOM (OEF) and IRAQI FREEDOM(OIF). Additionally, reported damage incidents were then validated by crosschecking aircraft maintenance records from this period to eliminate non-hostile fire data points. This revolutionary approach uncovered …

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X-Hale: The Development Of A Research Platform For The Validation Of Nonlinear Aeroelastic Codes, Alexander A. Kaszynski Mar 2011

X-Hale: The Development Of A Research Platform For The Validation Of Nonlinear Aeroelastic Codes, Alexander A. Kaszynski

Theses and Dissertations

In conjunction with the Air Force Institute of Technology (AFIT) and the Air Force Research Laboratory (AFRL), the University of Michigan has designed and is currently building a remotely piloted aircraft (RPA) experimental high altitude long endurance (X-HALE) aircraft to collect non-linear aeroelastic data to validate HALE aircraft design codes developed by academia, industry, and the federal government. While X-HALE is representative of HALE aircraft, the manufacturing and evaluation techniques are applicable to larger full size HALE aircraft such as the concepts being developed under Defense Advanced Research Projects Agency's (DARPA's) Vulture program. This paper documents the development of the …

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Heat Transfer Experiments On A Pulse Detonation Driven Combustor, Nicholas C. Longo Mar 2011

Heat Transfer Experiments On A Pulse Detonation Driven Combustor, Nicholas C. Longo

Theses and Dissertations

Heat transfer experiments were conducted using a heat exchanger behind a pulse detonation combustor and a Garrett automotive turbocharger at the Air Force Research Lab (AFRL). The equivalence ratio and purge fraction were held at 1.0 and 0.9, respectively, while the frequency of operation was varied from 10 to 12 Hz in 1 Hz movements, and the fill fraction was varied from 0.5 to 0.8 in 0.1 increments. Temperature measurements were calculated using an energy balance allowing for the calculation of heat exchanger inlet enthalpy. The heat exchanger inlet enthalpy was estimated to be the exit enthalpy of the turbocharger …

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