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  • 101
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    "We Burn to Learn" About Fuel-Air Mixing Within Aircraft Powerplants (2004)
    In:  Other Sources
    Details
    Publication Date: 2019-07-18
    Description: I am working with my branch s advanced diagnostics team to investigate fuel-air mixing in jet-fueled gas turbine combustors and jet-fuel reformers. Our data acquisition begins with bench-top experiments which will help with calibration of equipment for facility testing. While conducting the bench-top experiments I learned to align laser and optical equipment to collect data, to use the data acquisition software, and to process the data into graphs and images. which jet he1 is to be reformed into hydrogen. Testing will commence shortly, after which we will obtain and analyze data and meet a critical milestone for the end of September. I am also designing the layout for a Schlieren system that will be used during that time frame. A Schlieren instrument records changes in the refractive index distribution of transparent media like air flows. The refractive index distribution can then be related to density, temperature, or pressure distributions within the flow. I am working on a scheme to quantify this information and add to the knowledge of the fuel-air mixing process.
    Keywords: Aircraft Propulsion and Power
    Type: Research Symposium II
    Format: text
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    NASA TECHNICAL REPORTS
  • 102
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    Metal Foam Analysis: Improving Sandwich Structure Technology for Engine Fan and Propeller Blades (2004)
    In:  Other Sources
    Details
    Publication Date: 2019-07-18
    Description: The Life Prediction Branch of the NASA Glenn Research Center is searching for ways to construct aircraft and rotorcraft engine fan and propeller blades that are lighter and less costly. One possible design is to create a sandwich structure composed of two metal faces sheets and a metal foam core. The face sheets would carry the bending loads and the foam core would have to resist the transverse shear loads. Metal foam is ideal because of its low density and energy absorption capabilities, making the structure lighter, yet still stiff. The material chosen for the face sheets and core was 17-4PH stainless steel, which is easy to make and has appealing mechanical properties. This material can be made inexpensively compared to titanium and polymer matrix composites, the two current fan blade alternatives. Initial tests were performed on design models, including vibration and stress analysis. These tests revealed that the design is competitive with existing designs; however, some problems were apparent that must be addressed before it can be implemented in new technology. The foam did not hold up as well as expected under stress. This could be due to a number of issues, but was most likely a result of a large number of pores within the steel that weakened the structure. The brazing between the face sheets and the foam was also identified as a concern. The braze did not hold up well under shear stress causing the foam to break away from the face sheets. My role in this project was to analyze different options for improving the design. I primarily spent my time examining various foam samples, created with different sintering conditions, to see which exhibited the most favorable characteristics for our purpose. Methods of analysis that I employed included examining strut integrity under a microscope, counting the number of cells per inch, measuring the density, testing the microhardness, and testing the strength under compression. Shear testing will also be done to examine the strengths of different types of brazes.
    Keywords: Aircraft Propulsion and Power
    Type: Research Symposium II
    Format: text
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    NASA TECHNICAL REPORTS
  • 103
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    Induced Power of the Helicopter Rotor (2004)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: A simplified rotor model was used to explore fundamental behavior of lifting rotor induced power at moderate and high advance ratios. Several rotor inflow theories, including dynamic inflow theory and prescribed-wake vortex theory, together with idealized notional airfoil stall models were employed. A number of unusual results were encountered at high advance ratios including trim control reversal and multiple trim solutions. Significant increases in rotor induced power (torque) above the ideal minimum were observed for moderately high advance ratio. Very high induced power was observed near and above unity advance ratio. The results were sensitive to the stall characteristics of the airfoil models used. An equivalent wing analysis was developed to determine induced power from Prandtl lifting line theory and help interpret the rotor induced power behavior in terms of the spanwise airload distribution. The equivalent wing approach was successful in capturing the principal variations of induced power for different configurations and operating conditions. The effects blade root cutout were found to have a significant effect on rotor trim and induced power at high advance ratios.
    Keywords: Aircraft Propulsion and Power
    Type: American Helicopter Society 60th Annual Forum and Technology Display; Jun 08, 2004 - Jun 10, 2004; Baltimore, MD; United States
    Format: text
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    NASA TECHNICAL REPORTS
  • 104
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    High-Fidelity Full System Simulations (2004)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: High-fidelity full system simulations have the potential for revolutionizing the way complex systems, such as propulsion systems for aerospace vehicles, are designed, developed, manufactured, and operated. Significant time and cost savings will result from simulations that will resolve deleterious component interactions early in the design process. In addition, innovative new system configurations will result from the use of new tools that enable designers to challenge traditional rules and practices. The major challenges to developing and implementing high-fidelity systems simulations are in reducing the time and effort required to build, execute, and analyze data for the high complex simulations. In addition, large scale testing with unique instrumentation is required to validate the simulations. The solution to these problems reside in the application of advanced information technologies to assist the user to effectively manage, process, and synthesize the vast amount of data. The following presentation describes in more detail the benefits of high-fidelity full system simulations, the challenges to developing and implementing large scale simulations, and one approach that is being followed by the NASA Glenn Research Center to overcome these challenges. In addition, topics for discussion by the panel and audience are suggested.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/TM-2004-213309 , E-14769 , 40th Joint Propulsion Conference and Exhibit; Jul 11, 2004 - Jul 14, 2004; Fort Lauderdale, FL; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 105
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    Future Concepts for Modular, Intelligent Aerospace Power Systems (2004)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Nasa's resent commitment to Human and Robotic Space Exploration obviates the need for more affordable and sustainable systems and missions. Increased use of modularity and on-board intelligent technologies will enable these lofty goals. To support this new paradigm, an advanced technology program to develop modular, intelligent power management and distribution (PMAD) system technologies is presented. The many benefits to developing and including modular functionality in electrical power components and systems are shown to include lower costs and lower mass for highly reliable systems. The details of several modular technologies being developed by NASA are presented, broken down into hierarchical levels. Modularity at the device level, including the use of power electronic building blocks, is shown to provide benefits in lowering the development time and costs of new power electronic components.
    Keywords: Aircraft Propulsion and Power
    Type: International Energy Conversion Engineering Conference; Aug 15, 2004 - Aug 19, 2004; Providence, RI; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 106
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    The Challenges Facing Future Conversion Systems for Space Power Applications (2004)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: High-efficiency, Stirling power convertors have been proposed for space power applications, ranging from relatively low-power radioisotope generators such as the 110 watt SRG110 to the higher-power 100 kWe SP-100. The NASA Glenn Research Center (GRC) has been involved in the supporting technology and development for both of these systems. Although the power levels are quite different, many of the challenges faced by both of these dynamic power conversion systems similar. A major challenge is fund in demonstration of the capability for high reliability and long-life of the power system when the wear mechanisms have been eliminated. A review is presented of the past efforts, including the status of current flight development efforts, and a projection of what the future might bring.
    Keywords: Aircraft Propulsion and Power
    Type: E-14842 , International Energy Conversion Engineering Conference; Aug 16, 2004 - Aug 19, 2004; Providence, RI; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 107
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    Factors Affecting the Efficiency of Krypton Hall Thrusters (2004)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The krypton-fueled Hall thruster offers the possibility of high-specific impulse and long lifetime. NASA's series of Hall thrusters have demonstrated krypton efficiencies only 5 - 15% less than xenon. Larger thrusters have smaller differences in efficiency. Plasma measurements have demonstrated that efficiency is reduced due to a decrease in mass utilization. Current efforts are considering the implications of these results, and how design changes can be made to increase the efficiency of krypton Hall thrusters.
    Keywords: Aircraft Propulsion and Power
    Type: 46th Annual Meeting of the division of Plasma Physics; Nov 15, 2004 - Nov 19, 2004; Savannah, GA; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 108
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    Performance Characterization of a Lithium-ion Gel Polymer Battery Power Supply System for an Unmanned Aerial Vehicle (2004)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Unmanned aerial vehicles (UAVs) are currently under development for NASA missions, earth sciences, aeronautics, the military, and commercial applications. The design of an all electric power and propulsion system for small UAVs was the focus of a detailed study. Currently, many of these small vehicles are powered by primary (nonrechargeable) lithium-based batteries. While this type of battery is capable of satisfying some of the mission needs, a secondary (rechargeable) battery power supply system that can provide the same functionality as the current system at the same or lower system mass and volume is desired. A study of commercially available secondary battery cell technologies that could provide the desired performance characteristics was performed. Due to the strict mass limitations and wide operating temperature requirements of small UAVs, the only viable cell chemistries were determined to be lithium-ion liquid electrolyte systems and lithium-ion gel polymer electrolyte systems. Two lithium-ion gel polymer cell designs were selected as candidates and were tested using potential load profiles for UAV applications. Because lithium primary batteries have a higher specific energy and energy density, for the same mass and volume allocation, the secondary batteries resulted in shorter flight times than the primary batteries typically provide. When the batteries were operated at lower ambient temperatures (0 to -20 C), flight times were even further reduced. Despite the reduced flight times demonstrated, for certain UAV applications, the secondary batteries operated within the acceptable range of flight times at room temperature and above. The results of this testing indicate that a secondary battery power supply system can provide some benefits over the primary battery power supply system. A UAV can be operated for hundreds of flights using a secondary battery power supply system that provides the combined benefits of rechargeability and an inherently safer chemistry.
    Keywords: Aircraft Propulsion and Power
    Type: NASA/TM-2004-213401 , SAE-2004-01-3166 , E-14907 , Power Systems Conference; Nov 02, 2004 - Nov 04, 2004; Reno, NV; United States
    Format: application/pdf
    Location Call Number Expected Availability
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    NASA TECHNICAL REPORTS
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