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  • 1
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    Sur l'eau normale méditerraneenne: 1ère partie: Historique, discussion des méthodes, propositions (2016)
    Station Océanographique de Salammbô | Paris, France
    Details
    Publikationsdatum: 2021-05-19
    Beschreibung: La détermination de la chloruration des eaux de mer est effectuée depuis de nombreuses années par la méthode volémetrisque de Moher.
    Beschreibung: Published
    Schlagwort(e): Volumetric analysis ; Sea water ; Chemistry ; Density ; Water density ; Chlorination ; Methodology ; Marine
    Repository-Name: AquaDocs
    Materialart: Book/Monograph/Conference Proceedings , Refereed
    Format: 28pp.
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  • 2
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    [Perspective] Molecular sieves for gas separation (2016)
    American Association for the Advancement of Science (AAAS)
    In: Science
    Details
    Publikationsdatum: 2016-07-08
    Beschreibung: Separation and purification are critical industrial processes for separating components of chemical mixtures, and these processes account for about half of industrial energy usage (1). Gas mixtures of compounds with very similar physical properties are particularly difficult to separate. On pages 137 and 141 of this issue, Cadiau et al. (2) and Cui et al. (3), respectively, show that microporous materials can be designed to have high adsorption capacity and selectivity for particular hydrocarbons, enabling energy-efficient separation. Author: Jerry Y. S. Lin
    Schlagwort(e): Chemistry
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Geologie und Paläontologie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Publiziert von American Association for the Advancement of Science (AAAS)
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  • 3
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    [Perspective] How to break down crystalline cellulose (2016)
    American Association for the Advancement of Science (AAAS)
    In: Science
    Details
    Publikationsdatum: 2016-05-27
    Beschreibung: Biomass-degrading microorganisms use lytic polysaccharide monooxygenase (LPMO) enzymes to help digest cellulose, chitin, and starch. By cleaving otherwise inaccessible crystalline cellulose chains, these enzymes provide access to hydrolytic enzymes. LPMOs are of interest to biotechnology because efficient depolymerization of cellulose is a major bottleneck for the production of biologically based chemicals and fuels. On page 1098 of this issue, Kracher et al. (1) compare LPMO-reducing substrates in fungi from different taxonomic groups and lifestyles, based on both biochemical and genomic evidence. The results provide insights into reductive activation of LPMO that are important for developing more efficient industrial enzymes for lignocellulose biorefineries. Author: Angel T. Martínez
    Schlagwort(e): Chemistry
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Geologie und Paläontologie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Publiziert von American Association for the Advancement of Science (AAAS)
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  • 4
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    [Editors' Choice] Engineering open structures using DNA (2016)
    American Association for the Advancement of Science (AAAS)
    In: Science
    Details
    Publikationsdatum: 2016-03-25
    Beschreibung: Author: Marc S. Lavine
    Schlagwort(e): Chemistry
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Geologie und Paläontologie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Publiziert von American Association for the Advancement of Science (AAAS)
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  • 5
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    Quantum interference and diradicals [Chemistry] (2016)
    National Academy of Sciences
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    Publikationsdatum: 2016-01-27
    Beschreibung: An empirical observation of a relationship between a striking feature of electronic transmission through a π-system, destructive quantum interference (QI), on one hand, and the stability of diradicals on the other, leads to the proof of a general theorem that relates the two. Subject to a number of simplifying assumptions,...
    Schlagwort(e): Chemistry
    Print ISSN: 0027-8424
    Digitale ISSN: 1091-6490
    Thema: Biologie , Medizin , Allgemeine Naturwissenschaft
    Publiziert von National Academy of Sciences
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  • 6
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    [This Week in Science] Synthetic twists among lipids (2016)
    American Association for the Advancement of Science (AAAS)
    In: Science
    Details
    Publikationsdatum: 2016-04-29
    Beschreibung: Author: Jake Yeston
    Schlagwort(e): Chemistry
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Geologie und Paläontologie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Publiziert von American Association for the Advancement of Science (AAAS)
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  • 7
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    [This Week in Science] Temporarily caught in a bind (2016)
    American Association for the Advancement of Science (AAAS)
    In: Science
    Details
    Publikationsdatum: 2016-03-18
    Beschreibung: Author: Marc S. Lavine
    Schlagwort(e): Chemistry
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Geologie und Paläontologie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Publiziert von American Association for the Advancement of Science (AAAS)
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  • 8
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    [Perspective] Quantum dynamics in the smallest water droplet (2016)
    American Association for the Advancement of Science (AAAS)
    In: Science
    Details
    Publikationsdatum: 2016-03-18
    Beschreibung: Water plays a central role in scientific disciplines ranging from geology to astronomy to biology. Yet it is an extraordinarily dif cult liquid to understand because of its complex, ever-changing patterns of hydrogen bonds. Studies of small water clusters have provided important insights into the concerted hydrogen-bond motions that can occur in water. These studies are also crucial for developing an accurate potential function for simulating the properties of liquid water and ice (1). On page 1310 of this issue, Richardson et al. (2) provide evidence for a concerted type of motion in which two hydrogen bonds in a water cluster are broken simultaneously (see the figure). The results have implications for many areas of scientific study, including the chemistry of polar solvents, the conformations of proteins, and the dissolution of ions in minerals. Author: David C. Clary
    Schlagwort(e): Chemistry
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Geologie und Paläontologie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Publiziert von American Association for the Advancement of Science (AAAS)
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  • 9
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    [Editors' Choice] Beyond blank slates in the lab notebook (2016)
    American Association for the Advancement of Science (AAAS)
    In: Science
    Details
    Publikationsdatum: 2016-03-18
    Beschreibung: Author: Jake Yeston
    Schlagwort(e): Chemistry
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Geologie und Paläontologie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Publiziert von American Association for the Advancement of Science (AAAS)
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  • 10
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    [Perspective] Surprised by selectivity (2016)
    American Association for the Advancement of Science (AAAS)
    In: Science
    Details
    Publikationsdatum: 2016-03-04
    Beschreibung: Lower olefins, particularly ethylene (C2H4), propylene (C3H6), and butylene (C4H8), are important intermediates in the manufacture of products such as plastics, solvents, paints, and medicines. They are produced worldwide in amounts exceeding 200 million tons per year (see the photo) (1), mostly from crude oil. More recent approaches use methanol or synthesis gas (syngas; a mixture of carbon monoxide and hydrogen) as feedstocks, but capital investments are high and/or selectivities to lower olefins limited. A bifunctional catalyst reported by Jiao et al. on page 1065 of this issue (2) enables the direct conversion of synthesis gas to lower olefins with a surprisingly high selectivity. Author: Krijn P. de Jong
    Schlagwort(e): Chemistry
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Geologie und Paläontologie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Publiziert von American Association for the Advancement of Science (AAAS)
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  • 11
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    Ligand-accelerated enantioselective methylene C(sp3)-H bond activation (2016)
    American Association for the Advancement of Science (AAAS)
    In: Science
    Details
    Publikationsdatum: 2016-09-02
    Beschreibung: Effective differentiation of prochiral carbon–hydrogen (C–H) bonds on a single methylene carbon via asymmetric metal insertion remains a challenge. Here, we report the discovery of chiral acetyl-protected aminoethyl quinoline ligands that enable asymmetric palladium insertion into prochiral C–H bonds on a single methylene carbon center. We apply these palladium complexes to catalytic enantioselective functionalization of β-methylene C–H bonds in aliphatic amides. Using bidentate ligands to accelerate C–H activation of otherwise unreactive monodentate substrates is crucial for outcompeting the background reaction driven by substrate-directed cyclopalladation, thereby avoiding erosion of enantioselectivity. The potential of ligand acceleration in C–H activation is also demonstrated by enantioselective β-C–H arylation of simple carboxylic acids without installing directing groups.
    Schlagwort(e): Chemistry
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Geologie und Paläontologie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Publiziert von American Association for the Advancement of Science (AAAS)
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  • 12
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    [Editors' Choice] Sourcing hydrogen directly from wax (2016)
    American Association for the Advancement of Science (AAAS)
    In: Science
    Details
    Publikationsdatum: 2016-11-04
    Beschreibung: Author: Jake Yeston
    Schlagwort(e): Chemistry
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Geologie und Paläontologie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Publiziert von American Association for the Advancement of Science (AAAS)
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  • 13
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    [Editors' Choice] A clean combination of CO and amines (2016)
    American Association for the Advancement of Science (AAAS)
    In: Science
    Details
    Publikationsdatum: 2016-11-25
    Beschreibung: Author: Jake Yeston
    Schlagwort(e): Chemistry
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Geologie und Paläontologie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Publiziert von American Association for the Advancement of Science (AAAS)
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  • 14
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    [Perspective] Ammonia activation at a metal (2016)
    American Association for the Advancement of Science (AAAS)
    In: Science
    Details
    Publikationsdatum: 2016-11-11
    Beschreibung: Although ammonia (NH3) is made on a vast scale for use in fertilizers, its use as a chemical feedstock or as an energy carrier is much more limited. Many reactions that occur easily with its substitution products (amines) are sluggish for NH3, in part because of the difficulty of activating the N-H bond. For fuel cells, NH3 is attractive because it does not generate greenhouse gases, as do methanol and methane (1), and is more easily stored than hydrogen (H2). Amine-containing organic molecules are used in pharmaceutical and materials applications, and accessing these structures directly from ammonia could limit the generation of by-products during their synthesis (2). Bringing NH3 up to speed for these applications will require both the development of catalysts that can activate the strong N–H bond of ammonia and a fundamental understanding of the N–H bond cleavage step. On page 730 of this issue, Bezdek et al. (3) report a molybdenum complex capable of weakening the N–H bond of NH3 and releasing a H atom to generate H2 under mild conditions. Author: Jessica Hoover
    Schlagwort(e): Chemistry
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Geologie und Paläontologie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Publiziert von American Association for the Advancement of Science (AAAS)
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  • 15
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    Enantioselective cyanation of benzylic C-H bonds via copper-catalyzed radical relay (2016)
    American Association for the Advancement of Science (AAAS)
    In: Science
    Details
    Publikationsdatum: 2016-09-02
    Beschreibung: Direct methods for stereoselective functionalization of sp 3 -hybridized carbon–hydrogen [C(sp 3 )–H] bonds in complex organic molecules could facilitate much more efficient preparation of therapeutics and agrochemicals. Here, we report a copper-catalyzed radical relay pathway for enantioselective conversion of benzylic C–H bonds into benzylic nitriles. Hydrogen-atom abstraction affords an achiral benzylic radical that undergoes asymmetric C(sp 3 )–CN bond formation upon reaction with a chiral copper catalyst. The reactions proceed efficiently at room temperature with the benzylic substrate as limiting reagent, exhibit broad substrate scope with high enantioselectivity (typically 90 to 99% enantiomeric excess), and afford products that are key precursors to important bioactive molecules. Mechanistic studies provide evidence for diffusible organic radicals and highlight the difference between these reactions and C–H oxidations mediated by enzymes and other catalysts that operate via radical rebound pathways.
    Schlagwort(e): Chemistry
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Geologie und Paläontologie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Publiziert von American Association for the Advancement of Science (AAAS)
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  • 16
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    A highly active and stable IrOx/SrIrO3 catalyst for the oxygen evolution reaction (2016)
    American Association for the Advancement of Science (AAAS)
    In: Science
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    Publikationsdatum: 2016-09-02
    Beschreibung: Oxygen electrochemistry plays a key role in renewable energy technologies such as fuel cells and electrolyzers, but the slow kinetics of the oxygen evolution reaction (OER) limit the performance and commercialization of such devices. Here we report an iridium oxide/strontium iridium oxide (IrO x /SrIrO 3 ) catalyst formed during electrochemical testing by strontium leaching from surface layers of thin films of SrIrO 3 . This catalyst has demonstrated specific activity at 10 milliamps per square centimeter of oxide catalyst (OER current normalized to catalyst surface area), with only 270 to 290 millivolts of overpotential for 30 hours of continuous testing in acidic electrolyte. Density functional theory calculations suggest the formation of highly active surface layers during strontium leaching with IrO 3 or anatase IrO 2 motifs. The IrO x /SrIrO 3 catalyst outperforms known IrO x and ruthenium oxide (RuO x ) systems, the only other OER catalysts that have reasonable activity in acidic electrolyte.
    Schlagwort(e): Chemistry
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Geologie und Paläontologie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Publiziert von American Association for the Advancement of Science (AAAS)
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  • 17
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    [This Week in Science] Cooperation between frustrated partners (2016)
    American Association for the Advancement of Science (AAAS)
    In: Science
    Details
    Publikationsdatum: 2016-12-09
    Beschreibung: Author: Jake Yeston
    Schlagwort(e): Chemistry
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Geologie und Paläontologie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Publiziert von American Association for the Advancement of Science (AAAS)
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  • 18
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    Re: Penetration Behavior of Opposed Rows of Staggered Secondary Air Jets Depending on Jet Penetration Coefficient and Momentum Flux Ratio (2016)
    In:  CASI
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    Publikationsdatum: 2019-07-13
    Beschreibung: The purpose of this article is to explain why the extension of the previously published C = (S/Ho)sqrt(J) scaling for opposed rows of staggered jets wasn't directly successful in the study by Choi et al. (2016). It is not surprising that staggered jets from opposite sides do not pass each other at the expected C value, because Ho/D and sqrt(J) are much larger than the maximum in previous studies. These, and large x/D's, tend to suggest development of 2-dimensional flow. Although there are distinct optima for opposed rows of in-line jets, single-side injection, and opposed rows of staggered jets based on C, opposed rows of staggered jets provide as good or better mixing performance, at any C value, than opposed rows of in-line jets or jets from single-side injection.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: GRC-E-DAA-TN33874 , International Journal of Heat and Mass Transfer (e-ISSN 0017-9310); 102; 435-444
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 19
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    A Requirements-Driven Optimization Method for Acoustic Treatment Design (2016)
    In:  CASI
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    Publikationsdatum: 2019-07-13
    Beschreibung: Acoustic treatment designers have long been able to target specific noise sources inside turbofan engines. Facesheet porosity and cavity depth are key design variables of perforate-over-honeycomb liners that determine levels of noise suppression as well as the frequencies at which suppression occurs. Layers of these structures can be combined to create a robust attenuation spectrum that covers a wide range of frequencies. Looking to the future, rapidly-emerging additive manufacturing technologies are enabling new liners with multiple degrees of freedom, and new adaptive liners with variable impedance are showing promise. More than ever, there is greater flexibility and freedom in liner design. Subject to practical considerations, liner design variables may be manipulated to achieve a target attenuation spectrum. But characteristics of the ideal attenuation spectrum can be difficult to know. Many multidisciplinary system effects govern how engine noise sources contribute to community noise. Given a hardwall fan noise source to be suppressed, and using an analytical certification noise model to compute a community noise measure of merit, the optimal attenuation spectrum can be derived using multidisciplinary systems analysis methods. The subject of this paper is an analytical method that derives the ideal target attenuation spectrum that minimizes noise perceived by observers on the ground.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: GRC-E-DAA-TN31751 , AIAA/CEAS Aeroacoustics Conference; May 30, 2016 - Jun 01, 2016; Lyon; France
    Format: application/pdf
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  • 20
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    Impact of an Exhaust Throat on Semi-Idealized Rotating Detonation Engine Performance (2016)
    In:  CASI
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    Publikationsdatum: 2019-07-13
    Beschreibung: A computational fluid dynamic (CFD) model of a rotating detonation engine (RDE) is used to examine the impact of an exhaust throat (i.e. a constriction) on performance. The model simulates an RDE which is premixed, adiabatic, inviscid, and which contains an inlet valve that prevents backflow from the high pressure region directly behind the rotating detonation. Performance is assessed in terms of ideal net specific impulse which is computed on the assumption of lossless expansion of the working fluid to the ambient pressure through a notional diverging nozzle section downstream of the throat. Such a semi-idealized analysis, while not real-world, allows the effect of the throat to be examined in isolation from, rather than coupled to (as it actually is) various loss mechanisms. For the single Mach 1.4 flight condition considered, it is found that the addition of a throat can yield a 9.4 percent increase in specific impulse. However, it is also found that when the exit throat restriction gets too small, an unstable type of operation ensues which eventually leads to the detonation failing. This behavior is found to be somewhat mitigated by the addition of an RDE inlet restriction across which there is an aerodynamic loss. Remarkably, this loss is overcome by the benefits of the further exhaust restrictions allowed. The end result is a configuration with a 10.3 percent improvement in ideal net specific thrust.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: GRC-E-DAA-TN28815 , AIAA Aerospace Sciences Meeting (SciTech 2016); Jan 04, 2016 - Jan 08, 2016; San Diego, CA; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 21
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    Turboelectric Aircraft Drive Key Performance Parameters and Functional Requirements (2016)
    In:  CASI
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    Publikationsdatum: 2019-07-13
    Beschreibung: The purpose of this paper is to propose specific power and efficiency as the key performance parameters for a turboelectric aircraft power system and investigate their impact on the overall aircraft. Key functional requirements are identified that impact the power system design. Breguet range equations for a base aircraft and a turboelectric aircraft are found. The benefits and costs that may result from the turboelectric system are enumerated. A break-even analysis is conducted to find the minimum allowable electric drive specific power and efficiency that can preserve the range, initial weight, operating empty weight, and payload weight of the base aircraft.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: NASA/TM-2016-218919 , AIAA Paper 2015-3890 , E-19104-1 , GRC-E-DAA-TN26012 , AIAA Propulsion and Energy Forum 2015; Jul 27, 2015 - Jul 29, 2015; Orlando, FL; United States
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    NASA TECHNICAL REPORTS
  • 22
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    Vehicle Integrated Propulsion Research (VIPR) III Volcanic Ash Environment (VAE) Preliminary Visual and Teardown Observations (2016)
    In:  CASI
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    Publikationsdatum: 2019-07-13
    Beschreibung: This presentation will be used to develop a level of partnership that is not within the current NASA program for N+3 engine operations.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: DFRC-E-DAA-TN30644 , Aircraft Airworthiness and Sustainment Conference (AA&S 2016); Mar 21, 2016 - Mar 24, 2016; Grapevine, TX; United States
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    NASA TECHNICAL REPORTS
  • 23
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    Sensor Selection for Aircraft Engine Performance Estimation and Gas Path Fault Diagnostics (2016)
    In:  CASI
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    Publikationsdatum: 2019-07-13
    Beschreibung: This paper presents analytical techniques for aiding system designers in making aircraft engine health management sensor selection decisions. The presented techniques, which are based on linear estimation and probability theory, are tailored for gas turbine engine performance estimation and gas path fault diagnostics applications. They enable quantification of the performance estimation and diagnostic accuracy offered by different candidate sensor suites. For performance estimation, sensor selection metrics are presented for two types of estimators including a Kalman filter and a maximum a posteriori estimator. For each type of performance estimator, sensor selection is based on minimizing the theoretical sum of squared estimation errors in health parameters representing performance deterioration in the major rotating modules of the engine. For gas path fault diagnostics, the sensor selection metric is set up to maximize correct classification rate for a diagnostic strategy that performs fault classification by identifying the fault type that most closely matches the observed measurement signature in a weighted least squares sense. Results from the application of the sensor selection metrics to a linear engine model are presented and discussed. Given a baseline sensor suite and a candidate list of optional sensors, an exhaustive search is performed to determine the optimal sensor suites for performance estimation and fault diagnostics. For any given sensor suite, Monte Carlo simulation results are found to exhibit good agreement with theoretical predictions of estimation and diagnostic accuracies.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: NASA/TM-2016-218926 , GT2015-43744 , E-19182 , GRC-E-DAA-TN27315 , ASME Turbo Expo 2015; Jun 15, 2015 - Jun 19, 2015; Montreal, Quebec; Canada
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    NASA TECHNICAL REPORTS
  • 24
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    Efficient, Low Pressure Ratio Propulsor for Gas Turbine Engines (2016)
    In:  CASI
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    Publikationsdatum: 2019-07-12
    Beschreibung: A gas turbine engine includes a spool, a turbine coupled to drive the spool, and a propulsor that is coupled to be driven by the turbine through the spool. A gear assembly is coupled between the propulsor and the spool such that rotation of the turbine drives the propulsor at a different speed than the spool. The propulsor includes a hub and a row of propulsor blades that extends from the hub. The row includes no more than 20 of the propulsor blades.
    Schlagwort(e): Aircraft Propulsion and Power
    Format: application/pdf
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  • 25
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    Practical Techniques for Modeling Gas Turbine Engine Performance (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-12
    Beschreibung: The cost and risk associated with the design and operation of gas turbine engine systems has led to an increasing dependence on mathematical models. In this paper, the fundamentals of engine simulation will be reviewed, an example performance analysis will be performed, and relationships useful for engine control system development will be highlighted. The focus will be on thermodynamic modeling utilizing techniques common in industry, such as: the Brayton cycle, component performance maps, map scaling, and design point criteria generation. In general, these topics will be viewed from the standpoint of an example turbojet engine model; however, demonstrated concepts may be adapted to other gas turbine systems, such as gas generators, marine engines, or high bypass aircraft engines. The purpose of this paper is to provide an example of gas turbine model generation and system performance analysis for educational uses, such as curriculum creation or student reference.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: NASA/TM-2016-219147 , E-19270 , GRC-E-DAA-TN34474
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    Full-Scale Turbofan Engine Noise-Source Separation Using a Four-Signal Method (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-12
    Beschreibung: Contributions from the combustor to the overall propulsion noise of civilian transport aircraft are starting to become important due to turbofan design trends and expected advances in mitigation of other noise sources. During on-ground, static-engine acoustic tests, combustor noise is generally sub-dominant to other engine noise sources because of the absence of in-flight effects. Consequently, noise-source separation techniques are needed to extract combustor-noise information from the total noise signature in order to further progress. A novel four-signal source-separation method is applied to data from a static, full-scale engine test and compared to previous methods. The new method is, in a sense, a combination of two- and three-signal techniques and represents an attempt to alleviate some of the weaknesses of each of those approaches. This work is supported by the NASA Advanced Air Vehicles Program, Advanced Air Transport Technology Project, Aircraft Noise Reduction Subproject and the NASA Glenn Faculty Fellowship Program.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: NASA/TM-2016-219419 , E-19316 , GRC-E-DAA-TN36520
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  • 27
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    Dynamic Systems Analysis for Turbine Based Aero Propulsion Systems (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-12
    Beschreibung: The aircraft engine design process seeks to optimize the overall system-level performance, weight, and cost for a given concept. Steady-state simulations and data are used to identify trade-offs that should be balanced to optimize the system in a process known as systems analysis. These systems analysis simulations and data may not adequately capture the true performance trade-offs that exist during transient operation. Dynamic systems analysis provides the capability for assessing the dynamic tradeoffs at an earlier stage of the engine design process. The dynamic systems analysis concept, developed tools, and potential benefit are presented in this paper. To provide this capability, the Tool for Turbine Engine Closed-loop Transient Analysis (TTECTrA) was developed to provide the user with an estimate of the closed-loop performance (response time) and operability (high pressure compressor surge margin) for a given engine design and set of control design requirements. TTECTrA along with engine deterioration information, can be used to develop a more generic relationship between performance and operability that can impact the engine design constraints and potentially lead to a more efficient engine.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: NASA/TM-2016-219133 , E-19258 , GRC-E-DAA-TN31154
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  • 28
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    Investigation of Spiral and Sweeping Holes (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-18
    Beschreibung: Surface infrared thermography, hotwire anemometry, and thermocouple surveys were performed on two new film cooling hole geometries: spiral/rifled holes and fluidic sweeping holes. The spiral holes attempt to induce large-scale vorticity to the film cooling jet as it exits the hole to prevent the formation of the kidney shaped vortices commonly associated with film cooling jets. The fluidic sweeping hole uses a passive in-hole geometry to induce jet sweeping at frequencies that scale with blowing ratios. The spiral hole performance is compared to that of round holes with and without compound angles. The fluidic hole is of the diffusion class of holes and is therefore compared to a 777 hole and Square holes. A patent-pending spiral hole design showed the highest potential of the non-diffusion type hole configurations. Velocity contours and flow temperature were acquired at discreet cross-sections of the downstream flow field. The passive fluidic sweeping hole shows the most uniform cooling distribution but suffers from low span-averaged effectiveness levels due to enhanced mixing. The data was taken at a Reynolds number of 11,000 based on hole diameter and freestream velocity. Infrared thermography was taken for blowing ratios of 1.0, 1.5, 2.0, and 2.5 at a density ratio of 1.05. The flow inside the fluidic sweeping hole was studied using 3D unsteady RANS.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: GRC-E-DAA-TN35549 , Journal of Turbomachinery (ISSN 0889-504X) (e-ISSN 1528-8900); 138; 9
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  • 29
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    Sub-scale Waterflow Cavitation and Dynamic Transfer Function Testing of an Oxidizer Turbo-Pump Combined Inducer and Impeller (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-08-13
    Beschreibung: In 2009 and 2010, Concepts NREC prepared for and performed a series of tests on a 52% scale of a version of the Pratt & Whitney Rocketdyne J-2X Oxidizer Turbopump under a Phase III SBIR with NASA MSFC. The test article was a combined inducer and impeller, tested as a unit. This paper presents an overview of the test rig and facility, instrumentation, signal conditioning, data acquisition systems, testing approach, measurement developments, and lessons learned. Results from these tests were presented in the form of two papers at the previous JANNAF joint propulsion conference, in December of 2011.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: M16-5435 , Liquid Propulsion; Dec 05, 2016 - Dec 08, 2016; Phoenix, AZ; United States|Modeling and Simulation; Dec 05, 2016 - Dec 08, 2016; Phoenix, AZ; United States|JANNAF Joint Meeting; Dec 05, 2016 - Dec 08, 2016; Phoenix, AZ; United States|Spacecraft Propulsion; Dec 05, 2016 - Dec 08, 2016; Phoenix, AZ; United States
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  • 30
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    High-Lift Propeller System Configuration Selection for NASA's SCEPTOR Distributed Electric Propulsion Flight Demonstrator (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: Although the primary function of propellers is typically to produce thrust, aircraft equipped with distributed electric propulsion (DEP) may utilize propellers whose main purpose is to act as a form of high-lift device. These \high-lift propellers" can be placed upstream of wing such that, when the higher-velocity ow in the propellers' slipstreams interacts with the wing, the lift is increased. This technique is a main design feature of a new NASA advanced design project called Scalable Convergent Electric Propulsion Technology Operations Research (SCEPTOR). The goal of the SCEPTOR project is design, build, and y a DEP aircraft to demonstrate that such an aircraft can be much more ecient than conventional designs. This paper provides details into the high-lift propeller system con guration selection for the SCEPTOR ight demonstrator. The methods used in the high-lift propeller system conceptual design and the tradeo s considered in selecting the number of propellers are discussed.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: NF1676L-22853 , AIAA Aviation 2016; Jun 13, 2016 - Jun 17, 2016; Washington, DC; United States
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    Model-Based Engine Control Architecture with an Extended Kalman Filter (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: This paper discusses the design and implementation of an extended Kalman filter (EKF) for model-based engine control (MBEC). Previously proposed MBEC architectures feature an optimal tuner Kalman Filter (OTKF) to produce estimates of both unmeasured engine parameters and estimates for the health of the engine. The success of this approach relies on the accuracy of the linear model and the ability of the optimal tuner to update its tuner estimates based on only a few sensors. Advances in computer processing are making it possible to replace the piece-wise linear model, developed off-line, with an on-board nonlinear model running in real-time. This will reduce the estimation errors associated with the linearization process, and is typically referred to as an extended Kalman filter. The non-linear extended Kalman filter approach is applied to the Commercial Modular Aero-Propulsion System Simulation 40,000 (C-MAPSS40k) and compared to the previously proposed MBEC architecture. The results show that the EKF reduces the estimation error, especially during transient operation.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: GRC-E-DAA-TN28335 , AIAA SciTech 2016; Jan 04, 2016 - Jan 08, 2016; San Diego, CA; United States
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  • 32
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    Emission Characteristics of A P and W Axially Staged Sector Combustor (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: Emission characteristics of a three-cup P and W Axially Controlled Stoichiometry (ACS) sector combustor are reported in this article. Multiple injection points and fuel staging strategies are used in this combustor design. Pilot-stage injectors are located on the front dome plate of the combustor, and main-stage injectors are positioned on the top and bottom of the combustor liners downstream. Low power configuration uses only pilot-stage injectors. Main-stage injectors are added to high power configuration to help distribute fuel more evenly and achieve overall lean burn yielding very low NOx emissions. Combustion efficiencies at four ICAO LTO conditions were all above 99%. Three EINOx emissions correlation equations were developed based on the experimental data to describe the NOx emission trends of this combustor concept. For the 7% and 30% engine power conditions, NOx emissions are obtained with the low power configuration, and the EINOx values are 6.16 and 6.81. The high power configuration was used to assess 85% and 100% engine power NOx emissions, with measured EINOx values of 4.58 and 7.45, respectively. The overall landing-takeoff cycle NOx emissions are about 12% relative to ICAO CAEP/6 level.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: GRC-E-DAA-TN28388 , AIAA SciTech 2016; Jan 04, 2016 - Jan 08, 2016; San Diego, CA; United States
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  • 33
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    Virtual Flight Demonstration of the Stratospheric Dual-Aircraft Platform (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: A baseline configuration for the dual-aircraft platform (DAP) concept is described and evaluated in a physics-based flight dynamics simulations for two month-long missions as a communications relay in the lower stratosphere above central Florida. The DAP features two unmanned aerial vehicles connected via a long adjustable cable which effectively sail back-and-forth using wind velocity gradients and solar energy. Detailed atmospheric profiles in the vicinity of 60,000-ft derived from archived data measured by the 50-Mhz Doppler Radar Wind Profiler at Cape Canaveral are used in the flight simulations. An overview of the novel guidance and flight control strategies are provided. The energy-usage of the baseline configuration during month-long stationkeeping missions (i.e., within 150-mile radius of downtown Orlando) is characterized and compared to that of a pure solar aircraft.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: M16-5303 , AIAA Aviation 2016; Jun 13, 2016 - Jun 17, 2016; Washington, DC; United States
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  • 34
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    Propulsion System Dynamic Modeling of the NASA Supersonic Concept Vehicle for AeroPropulsoServoElasticity (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: A summary of the propulsion system modeling under NASA's High Speed Project (HSP) AeroPropulsoServoElasticity (APSE) task is provided with a focus on the propulsion system for the low-boom supersonic configuration developed by Lockheed Martin and referred to as the N+2 configuration. This summary includes details on the effort to date to develop computational models for the various propulsion system components. The objective of this paper is to summarize the model development effort in this task, while providing more detail in the modeling areas that have not been previously published. The purpose of the propulsion system modeling and the overall APSE effort is to develop an integrated dynamic vehicle model to conduct appropriate unsteady analysis of supersonic vehicle performance. This integrated APSE system model concept includes the propulsion system model, and the vehicle structural aerodynamics model. The development to date of such a preliminary integrated model will also be summarized in this report
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: NASA/TM-2016-218937 , AIAA Paper 2014-3684 , E-19185 , GRC-E-DAA-TN26748 , Joint Propulsion Conference; Jul 28, 2014 - Jul 30, 2014; Cleveland, OH; United States
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  • 35
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    Model-Based Engine Control Architecture with an Extended Kalman Filter (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: This paper discusses the design and implementation of an extended Kalman filter (EKF) for model-based engine control (MBEC). Previously proposed MBEC architectures feature an optimal tuner Kalman Filter (OTKF) to produce estimates of both unmeasured engine parameters and estimates for the health of the engine. The success of this approach relies on the accuracy of the linear model and the ability of the optimal tuner to update its tuner estimates based on only a few sensors. Advances in computer processing are making it possible to replace the piece-wise linear model, developed off-line, with an on-board nonlinear model running in real-time. This will reduce the estimation errors associated with the linearization process, and is typically referred to as an extended Kalman filter. The nonlinear extended Kalman filter approach is applied to the Commercial Modular Aero-Propulsion System Simulation 40,000 (C-MAPSS40k) and compared to the previously proposed MBEC architecture. The results show that the EKF reduces the estimation error, especially during transient operation.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: NASA/TM-2016-219066 , E-19199 , GRC-E-DAA-TN29222 , AIAA SciTech 2016; Jan 04, 2016 - Jan 08, 2016; San Diego, CA; United States
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  • 36
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    Building Blocks for Transport-Class Hybrid and Turboelectric Vehicles (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: NASA has been investing in research efforts to define potential vehicles that use hybrid and turboelectric propulsion to enable savings in fuel burn and carbon usage. This paper overviews the fundamental building blocks that have been derived from those studies and details what key performance parameters have been defined, what key ground and flight tests need to occur, and highlights progress toward each.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: GRC-E-DAA-TN35894 , Electric & Hybrid Aerospace Technology Symposium 2016; Nov 09, 2016 - Nov 10, 2016; Cologne; Germany
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  • 37
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    Alternative Bio-Derived JP-8 Class Fuel and JP-8 Fuel: Flame Tube Combustor Test Results Compared using a GE TAPS Injector Configuration (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: This paper presents results from tests in a NASA Glenn Research Center (GRC) flame tube facility, where a bio-derived alternate fuel was compared with JP-8 for emissions and general combustion performance. A research version of General Electric Aviation (GE) TAPS injector was used for the tests. Results include 2D, planar laser-based imaging as well as basic flow visualization of the flame. Four conditions were selected that simulate various engine power conditions relevant to NASA Fundamental Aeronautics Supersonics and Environmentally Responsible Aviation Projects were tested.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: GRC-E-DAA-TN34170 , AIAA/SAE/ASEE Joint Propulsion Conference; Jul 25, 2016 - Jul 27, 2016; Salt Lake City, UT; United States
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  • 38
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    Overview of Low Emission Combustion Research At NASA Glenn (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: An overview of research efforts at NASA Glenn Research Center (GRC) in low-emission combustion technology that have made a significant impact on the nitrogen oxides (NOx) emission reduction in aircraft propulsion is presented. The technology advancements and their impact on aircraft emissions are discussed in the context of NASA's Aeronautics Research Mission Directorate (ARMD) high-level goals in fuel burn, noise and emission reductions. The highlights of the research presented here show how the past and current efforts laid the foundation for the engines that are flying today as well as how the continued technology advancements will significantly influence the next generation of aviation propulsion system designs.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: GRC-E-DAA-TN31913 , ASME TURBO Expo 2016; Jun 13, 2016 - Jun 17, 2016; Seoul; Korea, Republic of
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  • 39
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    Proposal and Development of a High Voltage Variable Frequency Alternating Current Power System for Hybrid Electric Aircraft (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The development of ultra-efficient commercial vehicles and the transition to low-carbon emission propulsion are seen as thrust paths within NASA Aeronautics. A critical enabler to these paths comes in the form of hybrid-electric propulsion systems. For megawatt-class systems, the best power system topology for these hybrid-electric propulsion systems is debatable. Current proposals within NASA and the Aero community suggest using a combination of AC and DC for power transmission. This paper proposes an alternative to the current thought model through the use of a primarily high voltage AC power generation, transmission, and distribution systems, supported by the Convergent Aeronautics Solutions (CAS) Project. This system relies heavily on the use of dual-fed induction machines, which provide high power densities, minimal power conversion, and variable speed operation. The paper presents background on the project along with the system architecture, development status and preliminary results.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: GRC-E-DAA-TN33090 , AIAA/ASME/SAE/ASEE Joint Propulsion Conference; Jul 25, 2016 - Jul 27, 2016; Salt Lake City, UT; United States
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  • 40
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    Approximation of Engine Casing Temperature Constraints for Casing Mounted Electronics (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The performance of propulsion engine systems is sensitive to weight and volume considerations. This can severely constrain the configuration and complexity of the control system hardware. Distributed Engine Control technology is a response to these concerns by providing more flexibility in designing the control system, and by extension, more functionality leading to higher performing engine systems. Consequently, there can be a weight benefit to mounting modular electronic hardware on the engine core casing in a high temperature environment. This paper attempts to quantify the in-flight temperature constraints for engine casing mounted electronics. In addition, an attempt is made at studying heat soak back effects. The Commercial Modular Aero Propulsion System Simulation 40k (C-MAPSS40k) software is leveraged with real flight data as the inputs to the simulation. A two-dimensional (2-D) heat transfer model is integrated with the engine simulation to approximate the temperature along the length of the engine casing. This modification to the existing C-MAPSS40k software will provide tools and methodologies to develop a better understanding of the requirements for the embedded electronics hardware in future engine systems. Results of the simulations are presented and their implications on temperature constraints for engine casing mounted electronics is discussed.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: GRC-E-DAA-TN33158 , AIAA Joint Propulsion Conference 2016; Jul 25, 2016 - Jul 27, 2016; Salt Lake City, UT; United States
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  • 41
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    Mission Analysis and Aircraft Sizing of a Hybrid-Electric Regional Aircraft (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: No abstract available
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: NF1676L-23145 , AIAA 2016 SciTech Forum and Exposition; Jan 04, 2016 - Jan 08, 2016; San Diego, CA; United States
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  • 42
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    An Overview of Low-Emission Combustion Research at NASA Glenn (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: An overview of research efforts at NASA Glenn Research Center (GRC) in low-emission combustion technology that have made a significant impact on the nitrogen oxides (NOx) emission reduction in aircraft propulsion is presented. The technology advancements and their impact on aircraft emissions are discussed in the context of NASA's Aeronautics Research Mission Directorate (ARMD) high-level goals in fuel burn, noise and emission reductions. The highlights of the research presented here show how the past and current efforts laid the foundation for the engines that are flying today as well as how the continued technology advancements will significantly influence the next generation of aviation propulsion system designs.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: E-19204 , GT2016-56100 , GRC-E-DAA-TN30125 , ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition GT2016; Jun 13, 2016 - Jun 17, 2016; Seoul; Korea, Republic of
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    Enhancement of the Open National Combustion Code (OpenNCC) and Initial Simulation of Energy Efficient Engine Combustor (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: In this paper, we present the recent enhancement of the Open National Combustion Code (OpenNCC) and apply the OpenNCC to model a realistic combustor configuration (Energy Efficient Engine (E3)). First, we perform a series of validation tests for the newly-implemented advection upstream splitting method (AUSM) and the extended version of the AUSM-family schemes (AUSM+-up). Compared with the analytical/experimental data of the validation tests, we achieved good agreement. In the steady-state E3 cold flow results using the Reynolds-averaged Navier-Stokes(RANS), we find a noticeable difference in the flow fields calculated by the two different numerical schemes, the standard Jameson- Schmidt-Turkel (JST) scheme and the AUSM scheme. The main differences are that the AUSM scheme is less numerical dissipative and it predicts much stronger reverse flow in the recirculation zone. This study indicates that two schemes could show different flame-holding predictions and overall flame structures.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: AIAA Paper 2016-4651 , GRC-E-DAA-TN34851 , Joint Propulsion Conference; Jul 25, 2016 - Jul 27, 2016; Salt Lake City, UT; United States
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  • 44
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    Enhancement of the Open National Combustion Code (OpenNCC) and Initial Simulation of Energy Efficient Engine Combustor (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: In this paper, we present the recent enhancement of the Open National Combustion Code (OpenNCC) and apply the OpenNCC to model a realistic combustor configuration (Energy Efficient Engine (E3)). First, we perform a series of validation tests for the newly-implemented advection upstream splitting method (AUSM) and the extended version of the AUSM-family schemes (AUSM+-up). Compared with the analytical/experimental data of the validation tests, we achieved good agreement. In the steady-state E3 cold flow results using the Reynolds-averaged Navier-Stokes(RANS), we find a noticeable difference in the flow fields calculated by the two different numerical schemes, the standard Jameson- Schmidt-Turkel (JST) scheme and the AUSM scheme. The main differences are that the AUSM scheme is less numerical dissipative and it predicts much stronger reverse flow in the recirculation zone. This study indicates that two schemes could show different flame-holding predictions and overall flame structures.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: GRC-E-DAA-TN34437 , AIAA/SAE/ASEE Joint Propulsion Conference; Jul 25, 2016 - Jul 27, 2016; Salt Lake City, UT; United States
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  • 45
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    Parallel Hybrid Gas-Electric Geared Turbofan Engine Conceptual Design and Benefits Analysis (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The conceptual design of a parallel gas-electric hybrid propulsion system for a conventional single aisle twin engine tube and wing vehicle has been developed. The study baseline vehicle and engine technology are discussed, followed by results of the hybrid propulsion system sizing and performance analysis. The weights analysis for the electric energy storage & conversion system and thermal management system is described. Finally, the potential system benefits are assessed.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: GRC-E-DAA-TN33024 , AIAA/SAE/ASEE Joint Propulsion Conference, AIAA Propulsion and Energy Forum and Exposition 2016; Jul 25, 2016 - Jul 27, 2016; Salt Lake City, UT; United States
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  • 46
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    Optimizing Power Density and Efficiency of a Double-Halbach Array Permanent-Magnet Ironless Axial-Flux Motor (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: NASA Glenn Research Center is investigating hybrid electric and turboelectric propulsion concepts for future aircraft to reduce fuel burn, emissions, and noise. Systems studies show that the weight and efficiency of the electric system components need to be improved for this concept to be feasible. This effort aims to identify design parameters that affect power density and efficiency for a double-Halbach array permanent-magnet ironless axial flux motor configuration. These parameters include both geometrical and higher-order parameters, including pole count, rotor speed, current density, and geometries of the magnets, windings, and air gap.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: GRC-E-DAA-TN33010 , AIAA/SAE/ASEE Joint Propulsion Conference; Jul 25, 2016 - Jul 27, 2016; Salt Lake City, UT; United States
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    Commercial Supersonics Technology Project - Status of Airport Noise (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The Commercial Supersonic Technology Project has been developing databases, computational tools, and system models to prepare for a level 1 milestone, the Low Noise Propulsion Tech Challenge, to be delivered Sept 2016. Steps taken to prepare for the final validation test are given, including system analysis, code validation, and risk reduction testing.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: GRC-E-DAA-TN31478 , Acoustics Technical Working Group Meeting (Spring 2016); Apr 19, 2016 - Apr 20, 2016; Hampton, VA; United States
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 48
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    Hybrid Electric Propulsion Technologies for Commercial Transports (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: NASA Aeronautics Research Mission Directorate has set strategic research thrusts to address the major drivers of aviation such as growth in demand for high-speed mobility, addressing global climate and capitalizing in the convergence of technological advances. Transitioning aviation to low carbon propulsion is one of the key strategic research thrust and drives the search for alternative and greener propulsion system for advanced aircraft configurations. This work requires multidisciplinary skills coming from multiple entities. The Hybrid Gas-Electric Subproject in the Advanced Air Transportation Project is energizing the transport class landscape by accepting the technical challenge of identifying and validating a transport class aircraft with net benefit from hybrid propulsion. This highly integrated aircraft of the future will only happen if airframe expertise from NASA Langley, modeling and simulation expertise from NASA Ames, propulsion expertise from NASA Glenn, and the flight research capabilities from NASA Armstrong are brought together to leverage the rich capabilities of U.S. Industry and Academia.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: GRC-E-DAA-TN30861 , Green Aviation Technical Information Exchange; Mar 29, 2016 - Mar 31, 2016; Hampton, VA; United States
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 49
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    Variable Cycle Intake for Reverse Core Engine (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-08-26
    Beschreibung: A gas generator for a reverse core engine propulsion system has a variable cycle intake for the gas generator, which variable cycle intake includes a duct system. The duct system is configured for being selectively disposed in a first position and a second position, wherein free stream air is fed to the gas generator when in the first position, and fan stream air is fed to the gas generator when in the second position.
    Schlagwort(e): Aircraft Propulsion and Power
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 50
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    Gas Turbine Engine Having Fan Rotor Driven by Turbine Exhaust and with a Bypass (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-08-26
    Beschreibung: A gas turbine engine has a core engine incorporating a core engine turbine. A fan rotor is driven by a fan rotor turbine. The fan rotor turbine is in the path of gases downstream from the core engine turbine. A bypass door is moveable from a closed position at which the gases from the core engine turbine pass over the fan rotor turbine, and moveable to a bypass position at which the gases are directed away from the fan rotor turbine. An aircraft is also disclosed.
    Schlagwort(e): Aircraft Propulsion and Power
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 51
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    Gas Turbine Engine Inlet Wall Design (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-08-26
    Beschreibung: A gas turbine engine has an inlet duct formed to have a shape with a first ellipse in one half and a second ellipse in a second half. The second half has an upstream most end which is smaller than the first ellipse. The inlet duct has a surface defining the second ellipse which curves away from the first ellipse, such that the second ellipse is larger at an intermediate location. The second ellipse is even larger at a downstream end of the inlet duct leading into a fan.
    Schlagwort(e): Aircraft Propulsion and Power
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 52
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    Visions of the Future: Hybrid Electric Aircraft Propulsion (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The National Aeronautics and Space Administration (NASA) is investing continually in improving civil aviation. Hybridization of aircraft propulsion is one aspect of a technology suite which will transform future aircraft. In this context, hybrid propulsion is considered a combination of traditional gas turbine propulsion and electric drive enabled propulsion. This technology suite includes elements of propulsion and airframe integration, parallel hybrid shaft power, turbo-electric generation, electric drive systems, component development, materials development and system integration at multiple levels.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: GRC-E-DAA-TN34060 , Aircraft Electric/Hybrid-Electric Power & Propulsion Workshop; Jul 28, 2016; Salt Lake City, UT; United States
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 53
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    A Network Scheduling Model for Distributed Control Simulation (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: Distributed engine control is a hardware technology that radically alters the architecture for aircraft engine control systems. Of its own accord, it does not change the function of control, rather it seeks to address the implementation issues for weight-constrained vehicles that can limit overall system performance and increase life-cycle cost. However, an inherent feature of this technology, digital communication networks, alters the flow of information between critical elements of the closed-loop control. Whereas control information has been available continuously in conventional centralized control architectures through virtue of analog signaling, moving forward, it will be transmitted digitally in serial fashion over the network(s) in distributed control architectures. An underlying effect is that all of the control information arrives asynchronously and may not be available every loop interval of the controller, therefore it must be scheduled. This paper proposes a methodology for modeling the nominal data flow over these networks and examines the resulting impact for an aero turbine engine system simulation.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: GRC-E-DAA-TN33238 , AIAA/SAE/ASEE Joint Propulsion Conference; Jul 25, 2016 - Jul 27, 2016; Salt Lake City, UT; United States
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 54
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    Practical Techniques for Modeling Gas Turbine Engine Performance (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The cost and risk associated with the design and operation of gas turbine engine systems has led to an increasing dependence on mathematical models. In this paper, the fundamentals of engine simulation will be reviewed, an example performance analysis will be performed, and relationships useful for engine control system development will be highlighted. The focus will be on thermodynamic modeling utilizing techniques common in industry, such as: the Brayton cycle, component performance maps, map scaling, and design point criteria generation. In general, these topics will be viewed from the standpoint of an example turbojet engine model; however, demonstrated concepts may be adapted to other gas turbine systems, such as gas generators, marine engines, or high bypass aircraft engines. The purpose of this paper is to provide an example of gas turbine model generation and system performance analysis for educational uses, such as curriculum creation or student reference.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: GRC-E-DAA-TN33214 , AIAA/SAE/ASEE Joint Propulsion Conference; Jul 25, 2016 - Jul 27, 2016; Salt Lake City, UT; United States
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 55
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    Alternative Bio-Derived JP-8 Class Fuel and JP-8 Fuel: Flame Tube Combustor Test Results Compared using a GE TAPS Injector Configuration (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: This paper presents results from tests in a flame tube facility, where a bio-derived alternate fuel was compared with JP-8 for emissions and general combustion performance. A research version of General Electric Aviation (GE) TAPS injector was used for the tests. Results include combustion efficiency from gaseous emission measurements, 2D planar laser-based imaging as well as basic flow visualization of the flame. Four inlet test conditions were selected that simulate various engine power conditions relevant to NASA Fundamental Aeronautics Supersonics Project and Environmentally Responsible Aviation Program. One inlet condition was a pilot-only test point. The other three inlet conditions incorporated fuel staging via a split between the pilot and main circuits of either 10%/90% or 20%/80%. For each engine power condition, three fuel mixes were used: 100% JP-8; 100% alternative; and a blend of the two, containing 75% alternative. Results for the inlet cases that have fuel split between pilot and main, indicate that fuel from the pilot appears to be evaporated by the time it reaches the dome exit. Main circuit liquid evaporates within a downstream distance equal to annulus height, no matter the fuel. Some fuel fluorescence images for a 10%/90% fuel staging case show a distinct difference between JP-8 and bio-derived fuel. OH PLIF results indicate that OH forms in a region more centrally-located for the JP-8 case downstream of the pilot, in its central recirculation region (CRZ). For the bio-derived Hydrotreated Renewable Jet (HRJ) fuel, however, we do not see much OH in the CRZ. The OH image structure near the dome exit is similar for the two fuels, but farther downstream the OH in the CRZ is much more apparent for the JP-8 than for the alternate fuel. For all conditions, there was no discernable difference between fuel types in combustion efficiency or emissions.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: GRC-E-DAA-TN33118 , AIAA/SAE/ASEE Joint Propulsion Conference; Jul 25, 2016 - Jul 27, 2016; Salt Lake City, UT; United States
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 56
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    A Case for Basic Rotating Detonation Engine Research (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: A brief review is provided covering the benefits to air breathing and chemical rocket propulsion found from pressure gain combustion in general, and rotating detonation in particular. Challenges are also identified.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: GRC-E-DAA-TN32567 , DARPA RDE Stakeholders Day; May 26, 2016; Arlington, VA; United States
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 57
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    The Application of Hardware in the Loop Testing for Distributed Engine Control (2016)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The essence of a distributed control system is the modular partitioning of control function across a hardware implementation. This type of control architecture requires embedding electronics in a multitude of control element nodes for the execution of those functions, and their integration as a unified system. As the field of distributed aeropropulsion control moves toward reality, questions about building and validating these systems remain. This paper focuses on the development of hardware-in-the-loop (HIL) test techniques for distributed aero engine control, and the application of HIL testing as it pertains to potential advanced engine control applications that may now be possible due to the intelligent capability embedded in the nodes.
    Schlagwort(e): Aircraft Propulsion and Power
    Materialart: GRC-E-DAA-TN33270 , AIAA/SAE/ASEE Joint Propulsion Conference; Jul 25, 2016 - Jul 27, 2016; Salt Lake City, UT; United States
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
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