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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 847 records · Page 47

All sources NASA NTRS DOE OSTI

NASA NTRS2005

Water Injection Feasibility for Boeing 747 Aircraft

Can water injection be offered at a reasonable cost to large airplane operators to reduce takeoff NO( sub x) emissions? This study suggests it may be possible. This report is a contract deliverable to NASA Glenn Research Center from the prime contractor, The Boeing Commercial Airplane Company of Seattle, WA. This study was supported by a separate contract to the Pratt & Whitney Engine Company of Hartford, CT (contract number NNC04QB58P). Aviation continues to grow and with it, environmental pressures are increasing for airports that service commercial airplanes. The feasibility and performance of an emissions-reducing technology, water injection, was studied for a large commercial airplane (e.g., Boeing 747 with PW4062 engine). The primary use of the water-injection system would be to lower NOx emissions while an important secondary benefit might be to improve engine turbine life. A tradeoff exists between engine fuel efficiency and NOx emissions. As engines improve fuel efficiency, by increasing the overall pressure ratio of the engine s compressor, the resulting increased gas temperature usually results in higher NOx emissions. Low-NO(sub x) combustors have been developed for new airplanes to control the increases in NO(sub x) emissions associated with higher efficiency, higher pressure ratio engines. However, achieving a significant reduction of NO(sub x) emissions at airports has been challenging. Using water injection during takeoff has the potential to cut engine NO(sub x) emissions some 80 percent. This may eliminate operating limitations for airplanes flying into airports with emission constraints. This study suggests an important finding of being able to offer large commercial airplane owners an emission-reduction technology that may also save on operating costs.

Daggett, David L.↗

NASA NTRS2009

Design and Testing of Trace Contaminant Injection and Monitoring Systems

In support of the Carbon dioxide And Moisture Removal Amine Swing-bed (CAMRAS) testing, a contaminant injection system as well as a contaminant monitoring system has been developed by the Johnson Space Center Air Revitalization Systems (JSC-ARS) team. The contaminant injection system has been designed to provide trace level concentrations of contaminants generated by humans in a closed environment during space flight missions. The contaminant injection system continuously injects contaminants from three gas cylinders, two liquid reservoirs and three permeation ovens. The contaminant monitoring system has been designed to provide real time gas analysis with accurate flow, humidity and gas concentration measurements for collection during test. The contaminant monitoring system consists of an analytical real time gas analyzer, a carbon monoxide sensor, and an analyzer for ammonia and water vapor.

Broerman, Craig D.↗

NASA NTRS2009

Effectiveness of Shield Termination Techniques Tested with TEM Cell and Bulk Current Injection

This paper presents experimental results of the effectiveness of various shield termination techniques. Each termination technique is evaluated by two independent noise injection methods; transverse electromagnetic (TEM) cell operated from 3 MHz 400 MHz, and bulk current injection (BCI) operated from 50 kHz 400 MHz. Both single carrier and broadband injection tests were investigated. Recommendations as to how to achieve the best shield transfer impedance (i.e. reduced coupled noise) are made based on the empirical data. Finally, the noise injection techniques themselves are indirectly evaluated by comparing the results obtained from the TEM Cell to those from BCI.

Bradley, Arthur T.↗

NASA NTRS2009

Effects of Lightning Injection on Power-MOSFETs

Lightning induced damage is one of the major concerns in aircraft health monitoring. Such short-duration high voltages can cause significant damage to electronic devices. This paper presents a study on the effects of lightning injection on power metal-oxide semiconductor field effect transistors (MOSFETs). This approach consisted of pin-injecting lightning waveforms into the gate, drain and/or source of MOSFET devices while they were in the OFF-state. Analysis of the characteristic curves of the devices showed that for certain injection modes the devices can accumulate considerable damage rendering them inoperable. Early results demonstrate that a power MOSFET, even in its off-state, can incur considerable damage due to lightning pin injection, leading to significant deviation in its behavior and performance, and to possibly early device failures.

Celaya, Jose↗

NASA NTRS2011

Can Water-Injected Turbomachines Provide Cost-Effective Emissions and Maintenance Reductions?

An investigation has been performed to evaluate the effect of water injection on the performance of the Air Force Research Laboratory (AFRL, Wright-Patterson Air Force Base (WPAFB)) experimental trapped vortex combustor (TVC) over a range of fuel-to-air and water-to-fuel ratios. Performance is characterized by combustor exit quantities: temperature and emissions measurements using rakes, and overall pressure drop, from upstream plenum to combustor exit. Combustor visualization is performed using gray-scale and color still photographs and high-frame-rate videos. A parallel investigation evaluated the performance of a computational fluid dynamics (CFD) tool for the prediction of the reacting flow in a liquid fueled combustor (e.g., TVC) that uses water injection for control of pollutant emissions and turbine inlet temperature. Generally, reasonable agreement is found between data and NO(x) computations. Based on a study assessing the feasibility and performance impact of using water injection on a Boeing 747-400 aircraft to reduce NO(x) emissions during takeoff, retrofitting does not appear to be cost effective; however, an operator of a newly designed engine and airframe might be able to save up to 1.0 percent in operating costs. Other challenges of water injection will be discussed.

Hendricks, Robert C.↗

NASA NTRS2011

Two Azimuthally Separated Regions of Cusp Ion Injection Observed via Energetic Neutral Atoms

The low-energy neutral atom (LENA) imager on the IMAGE spacecraft can detect energetic neutral atoms produced by ion injection into the cusp through a charge exchange with the Earth's hydrogen exosphere. We examined the occurrence of the LENA cusp signal during positive IMF B(sub z) in terms of the arrival direction and the IMF clock angle theta(sub CA). Results of statistical analyses show that the occurrence frequency is high on the postnoon side when theta(sub CA) is between approximately 20 degrees and approximately 50 degrees. This is ascribed to ion injection caused by cusp reconnection typical of positive IMF B(sub z). Our results also show that there is another situation of high occurrence frequency, which can be identified with theta(sub CA) of approximately 30 degrees to approximately 80 degrees. When theta(sub CA) is relatively large (60 degrees - 80 degrees), occurrence frequencies are high at relatively low latitudes over a wide extent spanning both prenoon and postnoon sectors. This feature suggests that the ion injection is caused by reconnection at the dayside magnetopause. Its postnoon side boundary shifts toward the prenoon as theta(sub CA) decreases. When theta(sub CA) is less than approximately 50 degrees, the high occurrence frequency exists well inside the prenoon sector, which is azimuthally separated from the postnoon region ascribed to cusp reconnection. The prenoon region, which is thought due to ion injection caused by dayside reconnection, may explain the recent report that proton aurora brightening occurs in the unanticipated prenoon sector of the northern high-latitude ionosphere for IMF B(sub y) greater than 0 and B(sub z) greater than 0.

Abe, M.↗

NASA NTRS2012

Study of Forebody Injection and Mixing with Application to Hypervelocity Airbreathing Propulsion

The use of premixed, shock-induced combustion in the context of a hypervelocity, airbreathing vehicle requires effective injection and mixing of hydrogen fuel and air on the vehicle forebody. Three dimensional computational simulations of fuel injection and mixing from flush-wall and modified ramp and strut injectors are reported in this study. A well-established code, VULCAN, is used to conduct nonreacting, viscous, turbulent simulations on a flat plate at conditions relevant to a Mach 12 flight vehicle forebody. In comparing results of various fuel injection strategies, it is found that strut injection provides the greatest balance of performance between mixing efficiency and stream thrust potential.

Axdahl, Erik↗

NASA NTRSDate not supplied

Investigation of Liquid Fuel Injection Processes in a Rotating Detonation Combustor using Megahertz Planar Laser-Induced Fluorescence Imaging

Direct imaging of liquid fuel injection is performed within an optically accessible rotating detonation combustor (RDC) using planar laser-induced fluorescence (PLIF) to spatio-temporally resolve the highly dynamic spray characteristics at rates up to 1 MHz. The RDC is operated on air and hydrogen to sustain a stable, cyclically propagating detonation wave with cycle periods of up to ∼250 μs. One of the hydrogen fuel injection sites is replaced with a liquid jet to introduce a diesel spray as a fuel surrogate to enable tracer-free fluorescence excitation using the 355 nm third-harmonic output of a burst-mode Nd:YAG laser. The time-resolved PLIF measurements reveal the evolution of the highly unsteady spray, including the dwell period after the arrival of the detonation wave, the jet recovery, breakup and entrainment into the supersonic crossflow of air, propagation into the detonation chamber, and interaction with the detonation wave. Following passage of the detonation wave, the spray characteristics reveal significant changes in the momentum flux ratio between the liquid and air streams, altering the jet trajectory and temporarily halting fuel delivery to the detonation channel. This temporary cessation of fuel spray injection into the combustor is quantified, along with the fill rate as a function of time. As the injection system recovers, the fuel spray eventually returns to a quasi-steady position prior to the arrival of the detonation wave, allowing qualitative comparisons with theoretical jet trajectories for a range of air mass-flux conditions. These data, enabled by ultra-high-speed PLIF imaging, represent some of the first detailed measurements for characterizing and quantifying the interactions of liquid jets and detonations in an operating RDC.

Propulsion↗

NASA NTRSDate not supplied

Effect of Injection Dynamics on Wave Propagation in a Linear Detonation Combustor

Injector response to self-excited and sustained detonation wave propagation in an optically-accessible nonpremixed natural gas-oxygen linear detonation combustor is investigated. 100 kHz measurements of planar laser induced fluorescence (PLIF) of trace quantities of acetone injected into the fuel supply and simultaneous OH∗ chemiluminescence measurements were used to correlate the effect on injection dynamics on detonation wave structure and propagation. Measurements over a range of equivalence ratios (0.61-1.48) revealed wave propagation through regions of high fuel stratification in the axial and transverse direction of reactant injection. Consequently, the propagation of the detonation wave along the channel is through a flow-field with significant variation in fuel mass fraction, reactivity, and sound speeds. At lean conditions, wave propagation frequency is generally lower (∼6 kHz) resulting in longer time between wave passages for mixing and pre-heat resulting in steeper detonation wave-fronts anchored near the injector exit plane. Conversely, at rich equivalence ratios the wave frequency is higher (∼10 kHz) resulting in shorter intra-cycle period for reactant fill and mixing resulting waves lifted from the injection plane that are more compact. Higher chemiluminescence intensity in the post-wave region with deflagrative combustion is observed in these cases. Phase averaged representation of the acetone-PLIF measurements indicate that the fraction of time between wave passages available for reactant fill, mixing and pre-heat is consistent across all equivalence ratios.

Propulsion↗

NASA NTRSDate not supplied

Effect of Injection Dynamics on Detonation Wave Propagation in a Linear Detonation Combustor

Propulsion↗

NASA NTRS2022

Dynamical Perturbation of the Stratosphere by a Pyrocumulonimbus Injection of Carbonaceous Aerosols

The Pacific Northwest pyrocumulonimbus Event (PNE) took place in British Columbia during the evening and night-time hours between the 12th and 13th of August 2017. Several pyroconvective clouds erupted in this occasion, and released in the upper troposphere/lower stratosphere unprecedented amounts of carbonaceous aerosols (300 ktn). Only a few years later, an even larger pyroCb injection took place over Australia. This event, named the Australian New Year (ANY) event, injected up to 1100 ktn of aerosol between December 29th 2019 and January 4th 2020. Such large injections of carbonaceous aerosol modify the stratospheric radiative budgets, locally perturbing stratospheric temperatures and winds. In this study, we use the Goddard Earth Observing System Chemistry Climate Model (GEOS CCM) to study the pertubations on the stratospheric meteorology induced by an aerosol injection of the magnitude of the PNE. Our simulations include the radiative interactions of aerosols, so that their impact on temperatures and winds are explicitly simulated. We show how the presence of the carbonaceous aerosols from the pyroCb causes the formation and maintenance of a synoptic scale stratospheric anticyclone. We follow this disturbance considering the potential vorticity anomaly and the brown carbon aerosol loading and we describe its dynamical and thermodynamical structure and its evolution in time. The analysis presented here shows that the simulated anticyclone undergoes daily expansion-compression cycles governed by the radiative heating, which are directly related to the vertical motion of the plume, and that the aerosol radiative heating is essential in maintaining the anticyclone itself.

Pyrocumulonimbus↗

DOE OSTI2012

Updated Design of the Italian SuperB Factory Injection System

43 PARTICLE ACCELERATORS↗

DOE OSTI2012

Explaining the Cosmic-Ray E+/(E- + E+) and Anti-P/P Ratios Using a Steady-State Injection Model

We present a model of cosmic ray (CR) injection into the Galactic space based on recent {gamma}-ray observations of supernova remnants (SNRs) and pulsar wind nebulae (PWNe) by the Fermi Large Area Telescope (Fermi) and imaging atmospheric Cherenkov telescopes (IACTs). Steady-state injection of nuclear particles and electrons (e{sup -}) from the Galactic ensemble of SNRs, and electrons and positrons (e{sup +}) from the Galactic ensemble of PWNe are assumed, with their injection spectra inferred under guidance of {gamma}-ray observations and recent development of evolution and emission models. The ensembles of SNRs and PWNe are assumed to share the same spatial distributions. Assessment of possible secondary CR contribution from dense molecular clouds interacting with SNRs is also given. CR propagation in the interstellar space is handled by GALPROP. Different underlying source distribution models and Galaxy halo sizes are employed to estimate the systematic uncertainty of the model. We show that this observation-based model reproduces the positron fraction e{sup +}/(e{sup -} + e{sup +}) and antiproton-to-proton ratio ({bar p}/p) reported by PAMELA and other previous missions reasonably well, without calling for any speculative sources. A discrepancy remains, however, between the total e{sup -} + e{sup +} spectrum measured by Fermi and our model below {approx} 20 GeV, for which the potential causes are discussed. Important quantities for Galactic CRs including their energy injection, average lifetime in the Galaxy, and mean gas density along their typical propagation path are also estimated.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2012

The Injection System of the INFN-SuperB Factory Project: Preliminary Design

The ultra high luminosity B-factory (SuperB) project of INFN requires a high performance and reliable injection system, providing electrons at 4 GeV and positrons at 7 GeV, to fulfil the very tight requirements of the collider. Due to the short beam lifetime, continuous injection of electron and positron bunches in both LER and HER rings is necessary to maintain an high average luminosity. Polarized electrons are required for experiments and must be delivered by the injection system, due to the beam lifetime shorter than the ring polarization build-up: they will be produced by means of a SLAC-SLC polarized gun. The emittance and the energy spread of the e{sup -}/e{sup +} beams are reduced in a 1 GeV Damping Ring (DR) before injection in the main rings. Two schemes for positron production are under study, one with e{sup -}/e{sup +} conversion at low energy (< 1 Gev) and one with conversion at 6 GeV and a recirculation line to bring the positrons back to the DR. Acceleration through the Linac is provided by a 2856 MHz RF system made of travelling wave (TW), room temperature accelerating structures.

43 PARTICLE ACCELERATORS↗

DOE OSTI2013

Premixed direct injection disk

A fuel/air mixing disk for use in a fuel/air mixing combustor assembly is provided. The disk includes a first face, a second face, and at least one fuel plenum disposed therebetween. A plurality of fuel/air mixing tubes extend through the pre-mixing disk, each mixing tube including an outer tube wall extending axially along a tube axis and in fluid communication with the at least one fuel plenum. At least a portion of the plurality of fuel/air mixing tubes further includes at least one fuel injection hole have a fuel injection hole diameter extending through said outer tube wall, the fuel injection hole having an injection angle relative to the tube axis. The invention provides good fuel air mixing with low combustion generated NOx and low flow pressure loss translating to a high gas turbine efficiency, that is durable, and resistant to flame holding and flash back.

33 ADVANCED PROPULSION SYSTEMS↗

DOE OSTI2013

Premixed direct injection nozzle for highly reactive fuels

A fuel/air mixing tube for use in a fuel/air mixing tube bundle is provided. The fuel/air mixing tube includes an outer tube wall extending axially along a tube axis between an inlet end and an exit end, the outer tube wall having a thickness extending between an inner tube surface having a inner diameter and an outer tube surface having an outer tube diameter. The tube further includes at least one fuel injection hole having a fuel injection hole diameter extending through the outer tube wall, the fuel injection hole having an injection angle relative to the tube axis. The invention provides good fuel air mixing with low combustion generated NOx and low flow pressure loss translating to a high gas turbine efficiency, that is durable, and resistant to flame holding and flash back.

42 ENGINEERING↗

DOE OSTI2015

Fuel injection assembly for use in turbine engines and method of assembling same

A fuel injection assembly for use in a turbine engine is provided. The fuel injection assembly includes a plurality of tube assemblies, wherein each of the tube assemblies includes an upstream portion and a downstream portion. Each tube assembly includes a plurality of tubes that extend from the upstream portion to the downstream portion or from the upstream portion through the downstream portion. At least one injection system is coupled to at least one tube assembly of the plurality of tube assemblies. The injection system includes a fluid supply member that extends from a fluid source to the downstream portion of the tube assembly. The fluid supply member includes a first end portion located in the downstream portion of the tube assembly, wherein the first end portion has at least one first opening for channeling fluid through the tube assembly to facilitate reducing a temperature therein.

33 ADVANCED PROPULSION SYSTEMS↗

DOE OSTI2012

Creating fluid injectivity in tar sands formations

Methods for treating a tar sands formation are described herein. Methods for treating a tar sands may include heating a portion of a hydrocarbon layer in the formation from one or more heaters located in the portion. The heat may be controlled to increase the permeability of at least part of the portion to create an injection zone in the portion with an average permeability sufficient to allow injection of a fluid through the injection zone. A drive fluid and/or an oxidizing fluid may be provided into the injection zone. At least some hydrocarbons including mobilized hydrocarbons are produced from the portion.

04 OIL SHALES AND TAR SANDS↗