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Articles 39061 - 39090 of 196126

Full-Text Articles in Engineering

A Thematic And Reference Analysis Of Touchless Technologies, Eric R. Curia Mar 2022

A Thematic And Reference Analysis Of Touchless Technologies, Eric R. Curia

Theses and Dissertations

The purpose of this research is to explore the utility and current state of touchless technologies. Five categories of technologies are identified as a result of collecting and reviewing literature: facial/biometric recognition, gesture recognition, touchless sensing, personal devices, and voice recognition. A thematic analysis was conducted to evaluate the advantages and disadvantages of the five categories. A reference analysis was also conducted to determine the similarities between articles in each category. Touchless sensing showed to have the most advantages and least similar references. Gesture recognition was the opposite. Comparing analyses shows more reliable technology types are more beneficial and diverse.

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The Cyber Wargame Commodity Course Of Action Automated Analysis Method, Alex Hoffendahl Mar 2022

The Cyber Wargame Commodity Course Of Action Automated Analysis Method, Alex Hoffendahl

Theses and Dissertations

In the modern operational landscape, strategic decisions are made and executed, under uncertain conditions, with many potential constraints and limited information. The end goal of these decisions is to minimize and mitigate the effect of adversarial threats, which may or may not act in line with previous assumptions. Wargaming is a powerful tool that allows for the practical implementation of theoretical knowledge into real-world scenarios, enhancing decision-makers critical thinking and problem solving skills. Furthermore, including cyber-effects in a wargame leads to a broader decision scope for an entire operation. This research aims to enhance the analytical capabilities and overall usability …

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Inverse Optimization: Inferring Unknown Instance Parameters From Observed Decisions, Keith Batista Mar 2022

Inverse Optimization: Inferring Unknown Instance Parameters From Observed Decisions, Keith Batista

Theses and Dissertations

The objective of this research is to develop procedures that estimate selected, unknown parameters over an adversary's investment portfolio across a set of new or existing technologies. To solve for the selected unknown parameters, it is assumed that the adversary is maximizing the portfolio optimization problem and investing along the efficient frontier. The first technique is when an unknown risk attitude exists but all other parameters were known (i.e. expected return, variance, covariance). An adaptive line search technique that iteratively solved the portfolio optimization problem until the adversary's risk parameter was found. The second problem that was solved was when …

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Uav Positioning Data Determined Via Aruco Tags For Aircraft Surface Inspection, Caleb B. Schmidt Mar 2022

Uav Positioning Data Determined Via Aruco Tags For Aircraft Surface Inspection, Caleb B. Schmidt

Theses and Dissertations

Aircraft are frequently inspected to ensure that military and civilian safety standards are adhered to. These inspections are performed pre- and post-flight and are currently performed by trained maintenance personnel. This work furthers the automation of aircraft surface inspection by using ArUco tags to determine the position of the UAV during aerial inspections. The ArUco tag based position data was then compared to a highly accurate infrared motion capture system to determine the viability of this for accurate positioning of the vehicle. This work includes flight experiments with two different UAVs to perform a system viability comparison.

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Prioritizing Water Distribution Network Asset Maintenance Using Graph Theory Methods, Ashton E. Doyal Mar 2022

Prioritizing Water Distribution Network Asset Maintenance Using Graph Theory Methods, Ashton E. Doyal

Theses and Dissertations

Water distribution networks, like any other large infrastructure system, should be designed for reliability and resilience to resist failure. A literature review of graph theory methods pertaining to water distribution networks reveals a wide scope of mathematical and statistical measures that can be used to identify and classify many important features of a network. From this, an analysis using a combination of graph theory metrics and generated condition indices for the pipes is performed on the Tyndall drinking water system as a case study. The goal is to provide understanding to the risk of the current system and propose asset …

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Accelerating Transition To Production By Manufacturing Readiness Focus During Development, William K. Duncan Mar 2022

Accelerating Transition To Production By Manufacturing Readiness Focus During Development, William K. Duncan

Theses and Dissertations

The Department of Defense has adopted management tools, such as Manufacturing Readiness Levels (MRLs), which seek to address issues that have delayed the transition to production and delivery of deployment-ready systems. The MRL scale and assessment process institutes periodic reviews of products during the acquisition process. Specifically, MRLs provide a scale to measure, and importantly communicate, progress by evaluating and summarizing multiple aspects of product maturity. Unfortunately, issues are often identified during the periodic assessments which, if addressed earlier, would have further streamlined product delivery. The current research applies Model Based System Engineering tools to analyze and refine organizational structures …

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Airworthiness Decision Factors In The Us Air Force, Derek N. Dennis Mar 2022

Airworthiness Decision Factors In The Us Air Force, Derek N. Dennis

Theses and Dissertations

There are multiple airworthiness (AW) certification paths for aircraft platforms and their modifications. Specifically, military commercial derivative aircraft (MCDA) have a unique opportunity to pursue either FAA certification, military certification or a combination of both. Policy tells MCDA programs to pursue FAA certification to the maximum extent possible, however, the policy lacks clarity regarding where that extent ends. This concept of extent encompasses multiple factors and the choice of an AW basis is a complex decision. Under ideal conditions the decision maker, the program manager, has the experience and insight to support their decision, however, this is not always the …

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A Framework For Assessing Facility-Level Vulnerability And Risk To Extreme Weather Events, Blake A. Gawlik Mar 2022

A Framework For Assessing Facility-Level Vulnerability And Risk To Extreme Weather Events, Blake A. Gawlik

Theses and Dissertations

Intensifying extreme weather events, tied to the rise in the global average temperature, put global built infrastructure at risk. This presents a daunting challenge for organizational leaders who are tasked to determine how best to adapt current infrastructure to uncertain future events. To develop adaptation plans and policies, vulnerability and risk must be downscaled to an actionable scale, such that planners, designers, and engineers can make adaptation recommendations. However, previous research has largely assessed risk at coarser scales, e.g., regional, national, or global. These assessments are informative, but do not help those tasked to lead adaptation to make detailed, actionable …

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A Critical Review Of Climate Change On Coastal Infrastructure Systems, Gregory J. Howland Jr. Mar 2022

A Critical Review Of Climate Change On Coastal Infrastructure Systems, Gregory J. Howland Jr.

Theses and Dissertations

This thesis is a response to climate threats identified by DoD report on Climate Change in 2019. A critical review of climate change literature related to coastal infrastructure was conducted to synthesize past research and to inform future research. This review intends to inform how climate change may impact infrastructure systems, how those impacts are evaluated, can the investigation be improved, and what can stakeholders learn from the outcomes. The end goal is to find climate change mitigation strategies and adaptation measures, or identify the easiest path to get to that end. The compiled information will inform civilian and military …

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Carbon Estimation And Decision Making In Usaf Acquisition, Robert F. Gray Mar 2022

Carbon Estimation And Decision Making In Usaf Acquisition, Robert F. Gray

Theses and Dissertations

Recent executive orders and international agreements require the United States to significantly reduce its carbon and greenhouse gas emissions. The DoD is a significant contributor to the carbon emissions of the USA and will be required to reduce the emissions. Therefore, in order to make appropriate programmatic decisions the DoD needs to develop an appropriate method for estimating carbon and making programmatic decisions; trading-off carbon emissions with the traditional cost-schedule-performance metrics. This thesis examines the possibility of developing a model that can be used to estimate the carbon footprint of producing a system before detailed engineering designed have been complete.

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Quantifying Project Complexity To Resource Project Managers, Jereme R. Henrard Mar 2022

Quantifying Project Complexity To Resource Project Managers, Jereme R. Henrard

Theses and Dissertations

This research develops a multi-criteria decision analysis model to quantify project complexity and inform decision-makers in resource-constrained organizations with the Tyndall Program Management Office (PMO) as a case study. The complexity score is used as a risk metric to determine the appropriate number of skilled or novice project managers to effectively manage the PMO portfolio to mitigate cost and schedule overruns. The research provides an innovative approach to consider manning levels at the PMO and other project management-focused organizations/sections.

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Ground Vehicle Navigation With Depth Camera And Tracking Camera, Hongseok Kim Mar 2022

Ground Vehicle Navigation With Depth Camera And Tracking Camera, Hongseok Kim

Theses and Dissertations

The aim of this research is to provide autonomous navigation of a 4 wheel vehicle using commercial, off-the-shelf depth and tracking cameras. Some sensitive operations need accuracy within a few inches of navigation ability for indoor or outdoor scenarios where GPS signals are not available. Combination of the Visual Odometry (VO), Distance-Depth (D-D), and Object Detection data from the cameras can be used for accurate navigation and object avoidance. The Intel RealSense D435i, a depth camera, generates depth measurements and the relative position vector of an object. The Intel RealSense T265, a tracking camera, generates its own coordinate system and …

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System Phasing And Schedule Growth Analysis, Daniel A. Long Mar 2022

System Phasing And Schedule Growth Analysis, Daniel A. Long

Theses and Dissertations

Software development research, once a priority for the DoD, has received less focus in recent years. What research that has occurred has focused on size and cost prediction of software. Generally lacking in these studies is analysis on phase distributions and schedule. Putnam (1978) showed that there were measurable effects between early program management and final schedule growth, but these relationships have not been explored using the 2001-2021 DoD Software Resources Data Report (SRDR) database. Additionally, industry software development guidance provides rules of thumb for effort allocation, but a comparison of the rules to DoD software projects is nonexistent. This …

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Developing An Adaptable Best Value Contractor Selection Tool For Federal Construction Projects, Robert B. Kitson Mar 2022

Developing An Adaptable Best Value Contractor Selection Tool For Federal Construction Projects, Robert B. Kitson

Theses and Dissertations

Currently, there is no Air Force-wide best practice or standard for using an other-than lowest price source selection process for construction projects. Installations often award contracts using Lowest Price Technically Acceptable (LPTA) because of perceived cost and time savings. However, a heavy reliance on LPTA often leads to long-term decreases in quality and value. To allow the Air Force to receive the best value for its construction funding, a simple and adaptable tool was developed that allows installations to pursue contractor selection for construction projects by other-than lowest price methods. This research conducted a systematic literature review to obtain a …

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Hydrologic Profiles And Geospatial Trend Analysis Evaluating Recurrent Flooding At Coastal U.S. Air Force Installations, Dylan D. Bechen Mar 2022

Hydrologic Profiles And Geospatial Trend Analysis Evaluating Recurrent Flooding At Coastal U.S. Air Force Installations, Dylan D. Bechen

Theses and Dissertations

Military installations are exposed to numerous threats, including a changing climate and the risk of recurrent flooding. The four components of recurrent flooding are sea-level rise, tidal fluctuations, storm surges, and precipitation. This research analyzed 40 years of historical precipitation and tidal data at 17 coastal U.S. Air Force installations using indicators of both peak and threshold exceedances to identify long-term temporal trends in the hydrologic components that make up recurrent flood risk, establishing an installation’s “hydrologic profile” which can be used to better inform decision makers when evaluating portfolio-wide adaptation strategies and prioritization of long-term infrastructure investments.

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Life Cycle Analysis Of Hydrogen Fuel Derived From Aluminum Versus Diesel, Tyson S. Metlen Mar 2022

Life Cycle Analysis Of Hydrogen Fuel Derived From Aluminum Versus Diesel, Tyson S. Metlen

Theses and Dissertations

The Department of Defense needs energy sources beyond petroleum products to effectively combat area denial strategies employed by its adversaries. Petroleum fuels are expensive, they have deleterious environmental impacts, and most of the world’s oil reservoirs are in volatile countries. A proposed alternative energy carrier is reacting aluminum with water to produce hydrogen and using the hydrogen as a fuel source. Normally aluminum forms a protective oxide layer that prevents continuous reaction but if aluminum is mixed with a 3.5% by weight gallium-indium eutectic, the oxide layer cannot form, and the reaction is sustainable. This study conducts a life cycle …

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Geometric Generation Through The Merging Of Sysml, And Engineering Sketch Pad, Alexander J. Miesle Mar 2022

Geometric Generation Through The Merging Of Sysml, And Engineering Sketch Pad, Alexander J. Miesle

Theses and Dissertations

The United Stated Department of Defense (DoD) and Air Force (USAF) have placed increased emphasis on the utilization of modern systems engineering (SE) practices within the current and future acquisitions lifecycle. This call is driven by the current rate at which near-peer adversaries such as Russia and China are increasing their defense system capabilities and catching up or surpassing the Unites States in certain operational regions. To aid in the transition to a Digital Engineering and Digital Twin dominated acquisitions process, this thesis presents a method with which SysML and geometric tools can be linked within both new and existing …

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Investigating The Relationship Of Preventive And Corrective Maintenance In Chiller Assets Using Linear Regression Analysis, Jacob A. Franke Mar 2022

Investigating The Relationship Of Preventive And Corrective Maintenance In Chiller Assets Using Linear Regression Analysis, Jacob A. Franke

Theses and Dissertations

Asset managers must balance maintenance plans between preventive (PM) and corrective maintenance (CM). While PM plans have been a staple for decades, the benefits achieved have not been thoroughly examined at the asset specific level. This study focuses on the U.S. Air Force chiller portfolio to better understand the relationship between PM and CM, utilizing multiple stages of linear regression modeling and data from 14 US Air Force installations. PM and CM were found to be positively correlated, with PM accounting for relatively small portions of the variance experienced in CM. This study reveals the value of standardized data collection …

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Defining Resilience, Robustness, And Vulnerability Metrics To Guide Facilities And Infrastructure Decision Making For The United States Air Force, Kelly W. Minor Mar 2022

Defining Resilience, Robustness, And Vulnerability Metrics To Guide Facilities And Infrastructure Decision Making For The United States Air Force, Kelly W. Minor

Theses and Dissertations

Tyndall AFB was nearly destroyed after a category five hurricane named Michael tore through the Florida panhandle in 2018. A Program Management Office was stood up to coordinate, plan, and carry out the rebuild efforts of Tyndall AFB. The office’s primary responsibility is “building a base capable of supporting a 21st-century mission while also focusing on structural resiliency and efficiency” (Laidlaw 2019). Despite the requirement to build a resilient infrastructure portfolio, the United States Air Force has yet to fully quantify and qualify measures of resilience, including robustness and vulnerability, in the context of their current built infrastructure portfolio. This …

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Characterizing Complex-Valued Neural Network Model Approximations Of 4-Input 4-Output Complex-Valued Reference Block Models, Larry C. Llewellyn Ii Mar 2022

Characterizing Complex-Valued Neural Network Model Approximations Of 4-Input 4-Output Complex-Valued Reference Block Models, Larry C. Llewellyn Ii

Theses and Dissertations

System simulation models are often decomposed and abstracted as a collection of interconnected subsystem block models to facilitate system understanding, design, and analysis. Each subsystem block model contains mathematical functions that receive, process, and transmit signals that are modeled as real numbers, complex numbers, and/or logic values. This dissertation evaluates the use of a single two-layer complex-valued neural network model to approximate 4-input, 4-output subsystem reference block models in terms of accuracy, performance, and error. The research is novel in that it uses a neural network for continuous function approximation instead of data categorization; it uses a neural network designed …

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Investigation Into Engineering Change Order Costs And Appropriate Rules-Of-Thumb, Kaiana M. Miller Mar 2022

Investigation Into Engineering Change Order Costs And Appropriate Rules-Of-Thumb, Kaiana M. Miller

Theses and Dissertations

Engineering Change Orders (ECO) are technical requirements changes to existing contracts. To account for the potential increase in contract costs stemming from ECOs, current acquisition practice is to estimate a dollar value to hold in management reserve (MR) in case of ECO occurrence. Estimators often rely on rules-of-thumb when developing these estimates. Specifically, estimators use a 10% rule-of-thumb for estimating MR contract costs in the Development life cycle phase and a 5% rule-of-thumb for contracts in the Production or O&S life cycle phase. However, no empirical data supports or validates these 10% and 5% figures. Using a new data source, …

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Exploring The Value Of Training System Alternatives Through Methods Technologies, And Relevant Attributes, Brian R. Novitsky Mar 2022

Exploring The Value Of Training System Alternatives Through Methods Technologies, And Relevant Attributes, Brian R. Novitsky

Theses and Dissertations

Skilled maintainers are being lost at a higher rate than average of all enlisted career fields within the Air Force. Although incentive programs can provide some retention, attrition rates may continue to vary, placing the readiness of the warfighter in jeopardy. Additionally, the technologies used to train maintainers have evolved substantially, including augmented reality (AR) and virtual reality (VR) solutions, among others. These technologies have recently gained notoriety as novel ways to increase training effectiveness, providing avenues for maintainers to achieve greater skill levels at a faster rate than traditional platforms. Through semi-structured subject matter expert (SME) interviews, this qualitative …

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Developing A Methodology For Analyzing Educational Offerings Using Competency Descriptors, Andrew G. Lowe Mar 2022

Developing A Methodology For Analyzing Educational Offerings Using Competency Descriptors, Andrew G. Lowe

Theses and Dissertations

The United States Air Force needs to ensure its Airmen are receiving the best possible education so that they can perform their jobs as effectively as possible. One way to improve the evaluation and development of its Airmen is to incorporate the use of competencies to develop standards for performance and use competency-based education principles to improve the quality of education delivered to the Airmen. One of the educational centers of the United States Air Force is The Civil Engineer School. However, The Civil Engineer School needs a way to evaluate its current coursework on how well it develops competencies …

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Development And Assessment Of A Model-Based Framework On User Toolkits, Brandon J. Koury Mar 2022

Development And Assessment Of A Model-Based Framework On User Toolkits, Brandon J. Koury

Theses and Dissertations

The Department of Defense (DoD) has a limited number of resources to accomplish a variety of missions which involve deploying personnel to support and maintain aircraft operating throughout the world. The DoDs maintenance structure codes maintainers to perform maintenance on specific airframes. This structure limits the flexibility of maintainers and leads to deploying resources in a reactionary manner to address capability gaps in deployed environments. The Just-In-Time Multi-Mission Airman (JIT MMA) concept aims to resolve these issues. Currently, the necessary technologies are unknown, but user toolkits are a concept to consider. A user toolkit is a concept that allows users …

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Networked Cooperative Autonomous Munitions Digital Twin Modeling Utilizing Model Based Systems Engineering, Christopher R. Reed Mar 2022

Networked Cooperative Autonomous Munitions Digital Twin Modeling Utilizing Model Based Systems Engineering, Christopher R. Reed

Theses and Dissertations

An example of a high-complexity system is a swarm of Networked Cooperative Autonomous Munitions (NCAM) that prioritize wide area search and multiple view target confirmation. First, this research discusses methods toward building behavioral models within a Model-Based Systems Engineering (MBSE) tool. Then, this research presents the parallel modeling effort of NCAM in two environments: the MBSE model in Cameo Systems Modeler, and a physics-based model in the Advanced Framework for Simulation, Integration, and Modeling (AFSIM). Each digital model in its environment provides distinct benefits to the stakeholders of the design process, so the models must present consistent and parallel information. …

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The Application Of Virtual Reality In Firefighting Training, Dylan A. Gagnon Mar 2022

The Application Of Virtual Reality In Firefighting Training, Dylan A. Gagnon

Theses and Dissertations

Immersive simulations such as virtual reality is becoming more prevalent for use in training environments for many professions. United States Air Force firefighters may benefit from incorporating VR technology into their training program to increase organizational commitment, job satisfaction, self-efficacy, and job performance. With implementing a new training platform, it is also important to understand the relationship between these variables and the perceived benefits and efficacy of the VR training, which has not yet been studied in previous research. This study addresses this issue by gathering data from fire departments currently fielding a VR fire training platform.

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Efficiency Mapping And Determination Of Reliability, Resiliency And Vulnerability Of Atmospheric Water Generators In The United States, Erica F. Sadowski Mar 2022

Efficiency Mapping And Determination Of Reliability, Resiliency And Vulnerability Of Atmospheric Water Generators In The United States, Erica F. Sadowski

Theses and Dissertations

Atmospheric Water Generators (AWG) extract water from the air using one of three available technologies: refrigeration, sorption, and fog harvesting. A refrigeration device works like a dehumidifier and works best in conditions above 60% relative humidity. A sorption device utilizes a desiccant to extract the water vapor from the air and works in very low humidity levels. A fog harvesting device utilizes a mesh to capture the water vapor from the air and requires 100% relative humidity. In this research, I analyze two refrigeration-based devices and one sorption-based device and their efficacy in providing supplemental water supply. Due to climatological …

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Natural Infrastructure Alternatives Mitigate Hurricane-Driven Flood Vulnerability: Application To Tyndall Air Force Base, Kiara L. Vance Mar 2022

Natural Infrastructure Alternatives Mitigate Hurricane-Driven Flood Vulnerability: Application To Tyndall Air Force Base, Kiara L. Vance

Theses and Dissertations

Hurricane frequency and magnitude intensification are expected over the remainder of the twenty-first century. Uncertainty in future projections requires that coastal communities approach adaptation decisions with caution. Traditional approaches are costly and inflexible. Soft policy adaptations are largely unenforceable. Hard, natural adaptations have emerged as an opportunity to partially mitigate the growing risk of extreme flooding, without the large investments required for traditional approaches, where natural infrastructure already exists. Existing literature for natural adaptations has not leveraged intensification expectations for hurricane events. This research uses multihazard damage evaluation software and spatial analysis to investigate placement of dredged sediment as a …

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Investigation Of Additively Manufactured Molybdenum-Tungsten-Rhenium Alloys, Randolph T. Abaya Mar 2022

Investigation Of Additively Manufactured Molybdenum-Tungsten-Rhenium Alloys, Randolph T. Abaya

Theses and Dissertations

The process of creating metal components through additive manufacturing is changing the way different industries can avoid the shortcomings of traditional metal production. Metals such as tungsten, molybdenum, and rhenium have many advantages for different applications, especially when alloyed together. In this study, an additively manufactured alloy containing 70% molybdenum, 25% tungsten, and 5% rhenium (70Mo-25W-5Re) is tested for its strength, ductility, hardness, and porosity. The 70Mo-25W-5Re alloy is printed through Laser Powder Bed Fusion (LPBF) under different conditions such as printing speed and printing atmosphere. Additionally, the effects of post printing heat treatment are conducted to understand the advantages …

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Design And Application Of Compact Combustors In Small-Scale Jetcat Engines, Nathan A. Clark Mar 2022

Design And Application Of Compact Combustors In Small-Scale Jetcat Engines, Nathan A. Clark

Theses and Dissertations

Ultra-compact combustors (UCC) are an innovative approach to improving overall engine efficiency and thrust-to-weight ratio by reducing the axial length and weight of the engine. Previous efforts looked at integrating a UCC into a small-scale JetCat P90 engine utilizing gaseous propane fuel. The current investigation aimed to utilize the previous compact combustor design and switch fuels to liquid kerosene. Based on the results from testing, a new combustor was designed equipped with a different flame holding mechanism at the larger P400-scale while maintaining a length savings of 20%. Testing of the P400 compact combustors was performed within a newly designed …

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