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Articles 1 - 11 of 11
Full-Text Articles in Engineering
Numerical Analysis Of A Multi-Stage Elastohydrodynamic Seal For Aircraft Engines, Md Wasif Hasan
Numerical Analysis Of A Multi-Stage Elastohydrodynamic Seal For Aircraft Engines, Md Wasif Hasan
Electronic Theses and Dissertations
At present, both governmental and private aviation enterprises are trying to develop aircraft that are swifter, more lightweight, and more cost-effective in order to maintain competitiveness on both the domestic and global stage. Continuous innovation and sustainability efforts are necessary to achieve advancements in aviation systems, such as fans, compressors, combustors, and turbines, as well as sub-systems, like engine seals. Advanced engine seals exhibit considerable potential in enhancing the engine's pressure ratio and cycle temperatures, leading to reduced engine weight, increased thrust, and improved fuel economy. In this study, a novel multistage seal idea has been proposed for the supercritical …
Investigations Of A Surrogate Fuel Based On Fischer-Tropsch Gtl And Ctl In Cvcc, Idi And Di Compression Ignition Engines, Amanda C. Weaver
Investigations Of A Surrogate Fuel Based On Fischer-Tropsch Gtl And Ctl In Cvcc, Idi And Di Compression Ignition Engines, Amanda C. Weaver
Electronic Theses and Dissertations
With the increase in availability, feedstocks, and properties of alternative fuels, compatibility issues emerge between current engine platforms often requiring a limit on the blend percentage of alternative fuel in conventional fuel or alteration to the engine platform. Two key metrics were identified, autoignition quality and lubrication characteristics, as vital for the proper function of a compression ignition engine, and if the blend of alternative fuels matches these two criteria for the diesel standard, then the resulting blend percentage can be considered as a viable alternative for complete replacement of conventional petroleum ULSD. Autoignition quality was matched using blends S-8, …
Computational And Experimental Investigation Of Mass Reduced Aircraft Wing Ribs, Charles R. Fricks Iii
Computational And Experimental Investigation Of Mass Reduced Aircraft Wing Ribs, Charles R. Fricks Iii
Electronic Theses and Dissertations
This study seeks to develop and evaluate a novel design of mass reduced aircraft wing ribs through the topology optimization method. For comparison, the same examination is performed on ribs with normal internal geometry. The wing rib design is based on that of the Gulfstream G650 transonic jet. The rib was divided into three segments for analysis based around the positions of the two spars. Only the center section of the rib (that being between the forward and aft spars) is mass optimized, while the leading and trailing edges of the ribs (outside the spars) will be kept solid for …
Mitigation Of Aeroacoustic Noise Of A Fixed Wing Using Passive Flow Control, Cameron L. Perry
Mitigation Of Aeroacoustic Noise Of A Fixed Wing Using Passive Flow Control, Cameron L. Perry
Electronic Theses and Dissertations
As the world becomes more environmentally conscious, noise pollution is of increasing concern. In this study, shallow dimples are applied to a NACA 0012 airfoil at multiple angles of attack (AoA) with the intent of reducing aeroacoustic noise emissions. Both Reynolds Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) models are used for aerodynamic and aeroacoustic investigations, respectively, at a fixed Reynolds number of 4.8 x 105. Altering the dimple depth to diameter ratio (d/D) from 2.5% to 15% is first investigated, with a d/D of 5% or lower resulting in the least aerodynamic impact. The transition from …
Cfd And Heat Transfer Analysis Of Rocket Cooling Techniques On An Aerospike Nozzle, Geoffrey Sullivan
Cfd And Heat Transfer Analysis Of Rocket Cooling Techniques On An Aerospike Nozzle, Geoffrey Sullivan
Electronic Theses and Dissertations
In recent years the development of rocket engines has been mainly focused on improving the engine cycle and creating new fuels. Rocket nozzle design has not been changed since the late 1960s. Recent needs for reliable and reusable rockets, as well as advancements in additive manufacturing, have brought new interest into the aerospike nozzle concept. This nozzle is a type of altitude adjusting nozzle that is up to 90% more efficient than bell nozzles at low altitudes and spends up to 30% less fuel. Since the nozzle body is submerged in the hot exhaust gasses it is difficult to keep …
Investigations Of The Low Temperature Combustion Regions And Emissions Characteristics Of Aerospace F24 In A Constant Volume Combustion Chamber And A Common Rail Direct Injection Ci Engine, Richard C. Smith Iii
Investigations Of The Low Temperature Combustion Regions And Emissions Characteristics Of Aerospace F24 In A Constant Volume Combustion Chamber And A Common Rail Direct Injection Ci Engine, Richard C. Smith Iii
Electronic Theses and Dissertations
A study was conducted to investigate the low temperature combustion (LTC) regions of aerospace F24 and ULSD in the static setting of a CVCC and the dynamic setting of a CRDI research engine. This research is conducted to reduce in-cylinder emissions by understanding and implementing a technique to achieve an extended LTC. Emissions data for this study were collected during the operation of the CRDI research engine with a MKS 2030 FTIR and an AVL Microsoot 483. The parameters researched within the static setting of the CVCC included the determinations of the cool flames and NTC regions within the LTHR …
Comparative Analysis Of Winglet Efficiency On Supercritical Versus Traditionally Cambered Airfoils, Evan Cathers
Comparative Analysis Of Winglet Efficiency On Supercritical Versus Traditionally Cambered Airfoils, Evan Cathers
Electronic Theses and Dissertations
This study serves to define the performance of several industry-recognized and exploratory wing tip devices on aircraft wings utilizing contemporary supercritical airfoil geometry. For comparison, the same examination is performed on a wing comprised of traditionally cambered airfoils, the platform upon which winglets were initially developed. The supercritical wing design is based on that of the Airbus A320, while the conventional airfoil is based upon the Boeing 737-800 platform. Tip devices selected for analysis include blended, raked, split scimitar, fence, and spiroid winglets, as well as tip sails, characterized by the spreading of a bird’s primary flight feathers. Methodology for …
Mechanical Properties Of Nanomodified Hybrid Gfrp Composite Materials, Micah Rop Kimutai
Mechanical Properties Of Nanomodified Hybrid Gfrp Composite Materials, Micah Rop Kimutai
Electronic Theses and Dissertations
The mechanical behavior of the nanomodified hybrid epoxy matrix was investigated in glass fiber reinforced plastics (GFRP). In this study, five nanocomposites enriched with as received halloysite, nanomer I.28E, HNT-APTES, and the hybrid combinations of the two HNTs with the nanomer I.28E were successfully fabricated. To evaluate the effects and morphological characteristics of the individual fillers and the hybrid configurations on the epoxy resin matrix, TGA, DSC, and DMA were analyzed. To understand the effect of the five configurations on the neat GFRP laminate, mode I interlaminar fracture toughness, tensile, and vibration properties were investigated. Electron microscopy testing techniques were …
Experimental And Numerical Investigation Of Naca Airfoil Wing With Winglets, Courtney Danielle Bachmann
Experimental And Numerical Investigation Of Naca Airfoil Wing With Winglets, Courtney Danielle Bachmann
Electronic Theses and Dissertations
This research was performed in order to study wingtip devices and, in particular, winglets. Winglets are attached to commercial aircraft for the purpose of reducing induced drag caused by wake vortices on the wingtip. A winglet device can save an aircraft anywhere from 3-7% in fuel consumption. Over the course of a year, this can add up to hundreds of thousands of dollars saved. This research consisted of two parts: one part experiment and one part equipment design. The latter phase of this research examined various methods of testing in a subsonic wind tunnel laboratory setting. Experimental results found with …
Thermal Performance Of Sierpinski Carpet Fractal Fins At Various Angles Of Inclination In A Natural Convection Environment, Haidar Jamil Khalil
Thermal Performance Of Sierpinski Carpet Fractal Fins At Various Angles Of Inclination In A Natural Convection Environment, Haidar Jamil Khalil
Electronic Theses and Dissertations
As technology advances, higher performance cooling systems are desired to meet numerous thermal management challenges. Extended surfaces, also known as heat sinks or fins, are commonly used to passively dissipate unwanted heat from mechanical and electrical systems. Fractal fins in accordance with the first four iterations (including a base iteration) of the Sierpinski carpet, manufactured from AL-5052, were studied along seven different inclinations from 0° (orientated perpendicular to the direction of gravity) to 90° (orientated parallel to the direction of gravity), in iterations of 15°. The purpose of study was to investigate the thermal performance of the first four fractal …
Ultra-Fast, Autonomous, Reconfigurable Communication System, Paul Bupe Jr
Ultra-Fast, Autonomous, Reconfigurable Communication System, Paul Bupe Jr
Electronic Theses and Dissertations
The recent years have witnessed an increase in natural disasters in which the destruction of essential communication infrastructure has significantly affected the number of casualties. In 2005, Hurricane Katrina in the United States resulted in over 1,900 deaths, three million land-line phones disconnections, and more than 2000 cell sites going out of service. This incident highlighted an urgent need for a quick-deployment, efficient communication network for emergency relief purposes. In this research, a fully autonomous system to deploy Unmanned Aerial Vehicles (UAVs) as the first phase disaster recovery communication network for wide-area relief is presented. As part of this system, …