Conceptual Design Level Airframe/Propulsion Integration Using The Generic Synthesis Framework Avds.,
2022
University of Texas at Arlington
Conceptual Design Level Airframe/Propulsion Integration Using The Generic Synthesis Framework Avds., Harinkumar Patel
Mechanical and Aerospace Engineering Dissertations - Archive
In the past few decades there has been a significant growth in commercial aerospace transportation encompassing both atmospheric and space flight. In fact, the aircraft industry has seen several generations of engines and vehicles developed. While the space launch sector has switched from exclusively expandable rockets systems to including reusable rocket systems. Now, the current push in the industry is to develop a reusable in-atmosphere hypersonic transportation system. The development of any aircraft entails communicating the interactions among the principal design disciplines (aerodynamics, propulsion, structures, materials, etc.). For hypersonic vehicles, the interdependence of these interactions is enhanced to a level …
Robust Synthesis Methods For Cooperative Systems,
2022
University of Texas at Arlington
Robust Synthesis Methods For Cooperative Systems, Baris Taner
Mechanical and Aerospace Engineering Dissertations - Archive
Cooperative systems, like any other dynamic systems, suffer in performance because of uncertainty yet there is an added layer of uncertainty due to the communication among agents. Therefore, analytic solution to these problems are hard if not impossible. With the advancements in the linear and non-linear methods, i.e. linear matrix inequalities (LMI) and non-linear transformations, robust performance analysis and controller synthesis for cooperative systems can be reformulated as optimization problems with LMI constraints as has been done in the last two decades. Another aspect of the problem becomes visible as the cooperative system grows larger and that necessitates faster solution …
Effect Of Centrifugal Force On The Load Capacity Of Thrust Gas Bearing,
2022
University of Texas at Arlington
Effect Of Centrifugal Force On The Load Capacity Of Thrust Gas Bearing, Rakan Mohammed Haidar
Mechanical and Aerospace Engineering Theses - Archive
It has been known for many decades that both rigid and foil thrust bearings are two options in the market for high-speed turbomachinery systems. Their advantages encompass the lower manufacturing cost, the lighter weight, and the flexibility in allowing “component misalignment and runout.” When the operating fluid is air, the classical lubrication theory works perfectly. Any additional terms of the inertia effect might be somehow less significant and sometimes negligible since the viscous forces will be dominant, but this may not be the case if the bearing operates in a harsh environment, such as a high-pressure environment. Nonetheless, this is …
Energy Analysis Of Rear Door Heat Exchangers In Data Centers With Dynamic Workload Distribution,
2022
University of Texas at Arlington
Energy Analysis Of Rear Door Heat Exchangers In Data Centers With Dynamic Workload Distribution, Sai Abhideep Pundla
Mechanical and Aerospace Engineering Theses - Archive
In recent years, applications including IoT (Internet of Things), content delivery, and 5G have created a large demand for low-latency access to data processing and data storage. Traditional centralized data centers weren’t designed with those use cases in mind. Small data centers such as edge computing data centers and colocation data centers house more than half of all servers across the United States. Rear Door Heat exchangers (RDHx) provide an energy-efficient cooling solution to traditional CRAC/CRAH - based cooling methods by localizing the heat removal from the rack. With more control over air distribution through a shorter path between the …
Numerical Analysis Of Hybrid Server Immersed In Synthetic Dielectric Fluid,
2022
University of Texas at Arlington
Numerical Analysis Of Hybrid Server Immersed In Synthetic Dielectric Fluid, Bhavana Reddy Mandadi
Mechanical and Aerospace Engineering Theses - Archive
In recent years there has been a phenomenal development in cloud computing, networking, virtualization, and storage, which has increased the demand for data centers. With this increase, there is a demand for higher CPU (Central Processing Unit) performance and an increase in the Thermal Design Power (TDP). Maintaining the CPU temperature within the specified parameters for air-cooled servers is a challenge in thermal engineering (due to performance). One of the components of the Data Centers with the largest energy consumption is the cooling system, which uses over 40% of the energy. Advancements in DRAMs and the increased support of CPUs …
Conceptual Gas Turbine Hybrid Engine Design For High Speed Rail Locomotive Propulsion,
2022
University of Texas at Arlington
Conceptual Gas Turbine Hybrid Engine Design For High Speed Rail Locomotive Propulsion, Frank Roger Tennyson
Mechanical and Aerospace Engineering Theses - Archive
The modern experimental jet train developed by Bombardier Transportation was designed to partner with the present day electrified Acela high speed trains. The Jet train would provide transportation to areas (Rural etc.), as well as transcontinental capabilities to existing towns and cities where electrified propulsion units are not feasible. The Bombardier Jet Train utilizes petroleum-based fuel, diesel engine power, and multiple turboshaft engines, for higher speeds. The Pratt and Whitney PW150 engine design parameters will be used to develop the Conceptual Hybrid Turbo Shaft Engine (CHTS). The newer Conceptual Hybrid Turbo Shaft Engine (CHTS) should increase engine performance, lower specific …
Thermally Charging Capacitor: A New Protocol To Accurately Measure The Thermoelectric Potential,
2022
University of Texas at Arlington
Thermally Charging Capacitor: A New Protocol To Accurately Measure The Thermoelectric Potential, Amit Phalak
Mechanical and Aerospace Engineering Theses - Archive
Harvesting energy from waste heat would benefit in creating sustainable systems. Specifically, thermoelectric energy conversion can be used for low-grade waste heat recovery. However, the efficiency of conventional solid-state (i.e., semiconductor) has reached to the upper limit and could not make any advancement for more than 30 years. As a paradigm shift from solid-state thermoelectric conversion, in this study, ionic thermoelectric phenomena in liquid are explored. An electrolyte, with disproportionate size of anions and cations, when subjected to a temperature gradient can experience induced ion separation. In the phenomenon known as “Soret effect”, the smaller ions with higher mobility move …
An Integrated Design Tool For Tow-Steered Composite Laminate In Abaqus,
2022
University of Texas at Arlington
An Integrated Design Tool For Tow-Steered Composite Laminate In Abaqus, Twinkle Kothari
Mechanical and Aerospace Engineering Theses - Archive
The material of choice for contemporary aircraft and its component design over the past few decades has shifted more and more toward fiber-reinforced composites. This is mainly due to the improved strength, lightweight, corrosion resistance, design flexibility, and durability of composites over traditional metals. Advanced tailorable composites such as tow-steered composites can be designed and fabricated with fibers following prescribed curvilinear paths, which provides improved mechanical performance compared with unidirectional fiber-reinforced composites (UDFRCs). However, the potential of tow-steered composites oftentimes fails to be exploited due to the lack of design tools. Currently, there are no commercially available design tools for …
Lifting-Line Predictions For Life And Twist Distributions To Minimize Induced Drag In Ground Effect,
2022
Utah State University
Lifting-Line Predictions For Life And Twist Distributions To Minimize Induced Drag In Ground Effect, Kyler Church
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The elliptic lift distribution produces the minimum induced drag for a given wingspan and desired lift outside of ground effect. This distribution can be generated on any wing by using geometric and/or aerodynamic twist. However, in ground effect, the elliptic lift distribution is not necessarily that which minimizes induced drag. The present work uses a modern numerical lifting-line algorithm to evaluate how the optimum lift distribution varies as a function of height above ground. The algorithm is also used to obtain the twist distributions that should be applied to wings of varying aspect ratios and taper ratios to produce the …
Dual-Band Circularly Polarized Shared Aperture Antenna For Cubesat Communication System,
2022
University of South Alabama
Dual-Band Circularly Polarized Shared Aperture Antenna For Cubesat Communication System, Syed Salman Kabir
Graduate Theses and Dissertations (2019 - present)
For space exploration, a special class of small satellite known as CubeSat, has become popular in academia and industry in recent years. Due to its low cost and short development time, researchers prefer CubeSat over large-scale satellites wherever possible. In academia, CubeSat has major applications in the field of space atmosphere, space-to-ground communication, weather forecasting, etc. Like other spacecrafts, CubeSat uses multiple antennas in different frequency bands to establish a communication link with ground stations. Recent CubeSat missions are generating a large amount of data which cannot be downlinked using conventional antennas. The demand for a compact antenna system that …
Cryogenic Flow Boiling Heat Transfer On Additively Manufactured Liquid Rocket Engine Cooling Channels,
2022
University of Texas at El Paso
Cryogenic Flow Boiling Heat Transfer On Additively Manufactured Liquid Rocket Engine Cooling Channels, Debra Jazmin Ortega
Open Access Theses & Dissertations
The enhancement of flow boiling heat transfer is critical because it can solve thermal management issues seen across all engineering and manufacturing applications. Even though advancements are being made, more studies are needed to understand the behavior of forced convective boiling further.Currently, there are four major issues in the field of regenerative cooling of liquid rocket engines. 1. The cooling channels are typically manufactured using conventional machining, while aerospace industries are currently exploring the additive manufacturing approach. 2. The experimental critical heat flux values for cryogenic fluids are either lower or very close to the model predictions; however, the effect …
Carbon Fibers From Bio-Based Precursors Derived From Renewable Sources,
2022
Clemson University
Carbon Fibers From Bio-Based Precursors Derived From Renewable Sources, Sagar Kanhere
All Dissertations
Carbon fibers have the highest strength and modulus among all known fibers and are used as reinforcements in high-performance composites [1]. Carbon fibers also have a very low density relative to metals. Therefore, carbon fibers possess ultrahigh specific strength and modulus, which make them desirable for high-performance light-weight composites. A vast majority of commercial carbon fibers are produced from PAN precursors that are expensive, which limits the use of PAN-derived carbon fibers to aerospace applications (e.g., airplanes). However, for costsensitive applications, there is a need for low-cost, moderate performance carbon fibers. Lignin is a low-cost by-product of pulping and biorefining …
Project Management And Systems Engineering Framework For Educational Cubesat Missions,
2022
California Polytechnic State University, San Luis Obispo
Project Management And Systems Engineering Framework For Educational Cubesat Missions, Bailey Garrett
Master's Theses
The rising complexity of CubeSat missions and the unique challenges faced by educational CubeSat programs lead to high rates of mission failure. Implementing project management and systems engineering practices can alleviate these challenges and improve mission success rates for educational CubeSat developers. However, existing project management and systems engineering resources are too cumbersome and often assume the student has a base-level understanding of project management and systems engineering fundamentals. A new universal project management and systems engineering framework was created and tailored specifically to the needs of an educational CubeSat mission. The framework was designed to accommodate first-time CubeSat developers, …
Effects Of Atomic Oxygen On Outgassing Of Silicone Materials,
2022
California Polytechnic State University, San Luis Obispo
Effects Of Atomic Oxygen On Outgassing Of Silicone Materials, Samuel Westrick
Master's Theses
An important consideration for spacecraft material selection is the space environment that the spacecraft will be operating in. Two features of the space environment that drive material selection are material outgassing and the presence of atomic oxygen in low Earth orbit (LEO). Materials that are considered for use in space are tested to be able to understand how they’ll outgas on orbit and how they’ll respond to interactions with atomic oxygen. However, testing to understand how atomic oxygen interaction with a material will affect how the material will outgas is rare and not standardized. This thesis used a vacuum chamber …
Artificial Neural Network For Predicting Heat Transfer Rates In Supercritical Carbon Dioxide,
2022
Embry-Riddle Aeronautical University
Artificial Neural Network For Predicting Heat Transfer Rates In Supercritical Carbon Dioxide, Vinusha Dasarla Giri Babu
Doctoral Dissertations and Master's Theses
Supercritical carbon dioxide as a working fluid in a closed Brayton cycle is proving to be more efficient than a conventional steam-based Rankine engine. Understanding the heat transfer properties of supercritical fluids is important for the design of a working engine cycle. The thermophysical properties of supercritical fluids tend to vary non-linearly near the pseudo-critical region. Traditionally, empirical correlations are used to calculate the heat transfer coefficient. It has been shown in the literature and within our own studies that these correlations provide inaccurate predictions near the pseudo-critical line, where heat transfer may be deteriorated or enhanced, resulting from strong …
Natural 2d Layered Mineral Cannizzarite With Anisotropic Optical Responses,
2022
Missouri University of Science and Technology
Natural 2d Layered Mineral Cannizzarite With Anisotropic Optical Responses, Arindam Dasgupta, Xiaodong Yang, Jie Gao
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Cannizzarite is a naturally occurring mineral formed by van der Waals (vdW) stacking of alternating layers of PbS-like and Bi2S3-like two-dimensional (2D) materials. Although the PbS-type and Bi2S3-type 2D material layers are structurally isotropic individually, the forced commensuration between these two types of layers while forming the heterostructure of cannizzarite induces strong structural anisotropy. Here we demonstrate the mechanical exfoliation of natural cannizzarite mineral to obtain thin vdW heterostructures of PbS-type and Bi2S3-type atomic layers. The structural anisotropy induced anisotropic optical properties of thin cannizzarite flakes are explored through angle-resolved polarized Raman scattering, linear dichroism, and polarization-dependent anisotropic third-harmonic generation. …
2022 Summer-Fall Graduate Recognition Program,
2022
The University of Alabama in Huntsville
2022 Summer-Fall Graduate Recognition Program, Propulsion Research Center, Robert Frederick
PRC Graduate Recognition
This program includes the graduate recognition program for summer and fall 2022. Includes photographs, upcoming events, recent publications, and student profiles.
Accelerated Aging Of Adhesively Bonded Composite Joints For Use In Material Screening And Selection During Development: A Review And Case Study,
2022
Florida Institute of Technology
Accelerated Aging Of Adhesively Bonded Composite Joints For Use In Material Screening And Selection During Development: A Review And Case Study, Marie Danielle Flanigan
Theses and Dissertations
Adhesively bonded structures are used in many high-tech industries such as aerospace, automotive, and defense. The application of these joints using composite adherends has increased in recent years because of improved strength-to-weight ratio, design flexibility, and lower concern for corrosion. Quality acceptance of these structures largely depends on reliability and durability which includes influence of environmental service conditions on long-term behavior. Characterization of long-term behavior presents a difficult challenge to those involved in material selection and design due to the long service life of the joint compared to the development time available and complexity of the degradation mechanisms. Therefore, different …
Characterizing Climb And Propeller Performance For A Fixed Pitch, Single-Engine, Electric Aircraft,
2022
Florida Institute of Technology
Characterizing Climb And Propeller Performance For A Fixed Pitch, Single-Engine, Electric Aircraft, Austin Lawrence Andwan
Theses and Dissertations
Electric aircraft are on the horizon. Both industry and regulators have an abundance of flight tests ahead to ensure safe operation of these new aircraft. Conventional performance standards regaurding edurance, climb performance and cruise conditions are largely not applicable to assessing an electrically propulsed aircraft. While battery technologies are the current barrier for electric aircraft, there also hasn’t been much flight testing to reveal their unique performance trends. This experiment focus’s on characterizing some of these performance trends obtained through a level flight and climb test in the Pipistrel Velis Electro. The rate-of-climb did not exhibit a decrease when the …
Comparison Of Stability And Control Characteristics Of The Pipistrel Virus Sw And Pipistrel Velis Electro,
2022
Florida Institute of Technology
Comparison Of Stability And Control Characteristics Of The Pipistrel Virus Sw And Pipistrel Velis Electro, Sean Gregory Gunther
Theses and Dissertations
This document finds the stability and control affects of electric powerplant conversion on a pre-existing internal combustion powered Pipistrel Virus SW through comparison with the Pipistrel Velis Electro. Testing included analysis of both static and dynamic stability on the longitudinal and lateral-directional axes of the airplane. Due to the light sport airplane being used in testing, some of the intedended tests were unable to be performed, however, conclusions were still capable of being made. The primary conclusion is that electric conversion of an airframe has no significant negative consequences, with the airplane still exhibiting positive stability on all three axes. …
