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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 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Water-Cooled Total-Temperature Probe

Water-cooled supersonic total-pressure, static-pressure, and total-temperature probes developed to study high-temperature jet plumes. Total-temperature probe tested up to 2,000 degrees F incorporates annular cooling system up to thermocouple lead. Lead extends into test chamber to sense temperature of supersonic external flow. Design novel and significant. Applicable in development of jet engines and in research on fast flows of hot gases.

Lagen, Nicholas T.↗
NASA NTRS2000

SUPREM-DSMC: A New Scalable, Parallel, Reacting, Multidimensional Direct Simulation Monte Carlo Flow Code

An AFRL/NRL team has recently been selected to develop a scalable, parallel, reacting, multidimensional (SUPREM) Direct Simulation Monte Carlo (DSMC) code for the DoD user community under the High Performance Computing Modernization Office (HPCMO) Common High Performance Computing Software Support Initiative (CHSSI). This paper will introduce the JANNAF Exhaust Plume community to this three-year development effort and present the overall goals, schedule, and current status of this new code.

Campbell, David↗
NASA NTRS1991

High-speed laser anemometry based on spectrally resolved Rayleigh scattering

Laser anemometry in unseeded flows based on the measurement of the spectrum of Rayleigh scattered laser light is reviewed. The use of molecular scattering avoids the well known problems (particle lag, biasing effects, seed generation, seed injection) of seeded flows. The fundamental limits on velocity measurement accuracy are determined using maximum likelihood methods. Measurement of the Rayleigh spectrum with scanning Fabry-Perot interferometers is analyzed and accuracy limits are established for both single pass and multipass configurations. Multipass configurations have much higher selectivity and are needed for measurements where there is a large amount of excess noise caused by stray laser light. It is shown that Rayleigh scattering is particularly useful for supersonic and hypersonic flows. The results of the analysis are compared with measurements obtained with a Rayleigh scattering diagnostic developed for study of the exhaust plume of a small hydrogen-oxygen rocket, where the velocities are in the range of 1000 to 5000 m/sec.

Seasholtz, Richard G.↗
NASA NTRS1991

High-speed laser anemometry based on spectrally resolved Rayleigh scattering

Laser anemometry in unseeded flows based on the measurement of the spectrum of Rayleigh scattered laser light is reviewed. The use of molecular scattering avoids the well-known problems (particle lag, biasing effects, seed generation, seed injection) of seeded flows. The fundamental limits on velocity measurement accuracy are determined using maximum likelihood methods. Measurement of the Rayleigh spectrum with scanning Fabry-Perot interferometers is analyzed and accuracy limits are established for both single pass and multi-pass configurations. Multi-pass configurations have much higher selectivity and are needed for measurements where there is a large amount of excess noise caused by stray laser light. It is shown that Rayleigh scattering is particularly useful for supersonic and hypersonic flows. The results of the analysis are compared with measurements obtained with a Rayleigh scattering diagnostic developed for study of the exhaust plume of a small hydrogen-oxygen rocket, where the velocities are in the range 1000 to 5000 m/sec.

Seasholtz, R. G.↗
NASA NTRS2000

Experimental Results of the Impact of an Ion Thruster Plasma on Microwave Propagation

Electric thrusters are being considered for a variety of space missions because of the significant propellant savings that result from the use of high performance, electric propulsion technologies. Propellant mass savings reduces spacecraft launch requirements and increases mission lifetime and payload. The impact of electric thruster plasma plumes on microwave signal propagation however is an important spacecraft integration concern. Arcjets were the first electric thrusters to be considered for operational missions. Ling, et al. studied the effect of arcjet plumes on propagation. Arcjets produce a lightly ionized plume and Ling's analysis predicted that the plume would have a negligible effect on communication. Plumes from the higher performance ion thrusters being developed exhibit higher ionization levels, plasma temperatures and particle velocities than arcjets. Therefore, there was a need to assess the impact due to these plumes. To address this need, the authors designed and performed a series of experiments to examine propagation effects of plumes. The challenge with these experiments was that they had to be performed in the operational environment of the thruster. Therefore, the experiments were conducted inside a metal chamber which could be depressurized to simulate a near vacuum condition of space. The metal chamber presents a potential large source of error to the propagation measurements due to the corruption of the desired data by multiple wall reflections within the chamber. This chamber effect was minimized by employing a pulsed-continuous wave transmitter and receiver system. This system based on an HP8510 Network Analyzer, uses external hardware time gating to eliminate the clutter of the spurious reflections. Additionally, high gain antennas were used in the measurements to ensure that minimal amounts of energy were transmitted/received in undesirable directions. The measurements took place in Vacuum Facility 5 of the Electric Propulsion Laboratory at the NASA Glenn Research Center. This facility utilizes a cylindrical, stainless steel, vacuum chamber, which is 18.3 m long and 4.6 m in diameter. For the tests being described here a 30 cm diameter, xenon ion thruster was used. The thruster provided between 500 W and 2.3 kW of operating power. The thruster was mounted on a stand along the axis of the chamber near one of its ends and could be moved axially.

Zaman, Afroz J.↗
NASA NTRS2004

Status of the Geostationary Spectrograph (GeoSpec) for Earth and Atmospheric Science Applications

GeoSpec will support future satellite mission concepts in the Atmospheric Sciences and in Land and Ocean Sciences by providing time-resolved measurements of both chemically linked atmospheric trace gas concentrations of important molecules such as O3, NO2, CH2O and SO2 and at the same time coastal and ocean pollution events, tidal effects, and the origin and evolution of aerosol plumes. The instrument design concept in development is a dual spectrograph covering the WMS wavelength region of 310-500 nm and the VIS/NIR wavelength region of 480-900 nm coupled to all reflective telescope and high sensitivity PIN/CMOS area detector. The goal of the project is to demonstrate a system capable of making moderate spatial resolution (750 meters at nadir) hyperspectral measurements (0.6 to 1.2 nm resolution) from a geostationary orbit. This would enable studies of time-varying pollution and coastal change processes with a temporal resolution of 5 minutes on a regional scale to 1 hour on a continental scale. Other spatial resolutions can be supported by varying the focal length of the input telescope. Scientific rationale and instrument design and status will be presented.

Janz, Scott↗
NASA NTRS2009

Rendezvous Integration Complexities of NASA Human Flight Vehicles

Propellant-optimal trajectories, relative sensors and navigation, and docking/capture mechanisms are rendezvous disciplines that receive much attention in the technical literature. However, other areas must be considered. These include absolute navigation, maneuver targeting, attitude control, power generation, software development and verification, redundancy management, thermal control, avionics integration, robotics, communications, lighting, human factors, crew timeline, procedure development, orbital debris risk mitigation, structures, plume impingement, logistics, and in some cases extravehicular activity. While current and future spaceflight programs will introduce new technologies and operations concepts, the complexity of integrating multiple systems on multiple spacecraft will remain. The systems integration task may become more difficult as increasingly complex software is used to meet current and future automation, autonomy, and robotic operation requirements.

Brazzel, Jack P.↗
NASA NTRS2020

Concerning the Interaction of A Transmitted Interplanetary Impulse With A Plasmaspheric Drainage Plume: First Results From 3-D Hybrid Kinetic Modeling

We present a new hybrid kinetic model to simulate the response of plasmaspheric drainage plumes to impulsive interplanetary pressure pulses. Since particle distributions attending the interplanetary pulses and in the drainage plume are non-Maxwellian, wave-particle interactions play a crucial role in energy transport within and outside the plumes. Finite gyroradius effects become important in mass loading of the transmitted impulse with the drainage plume ions. A forward-reverse shock structure develops from the initial step-like transmitted shock. First results show that the impulse causes strong deformations in the global structure of the plume. The anisotropic ion velocity distribution functions at the impulse front and inside the plume help us determine energy transport via wave-particle interactions throughout the Earth’s inner magnetosphere.

A S Lipatov↗
NASA NTRS2000

Experimental Results of the Impact of an Ion Thruster Plasma on Microwave Propagation

Electric thrusters are being considered for a variety of space missions because of the significant propellant savings that result from the use of high performance, electric propulsion technologies, Propellant mass savings reduces spacecraft launch requirements and increases mission lifetime and payload. The impact of electric thruster plasma plumes on microwave signal propagation however is an important spacecraft integration concern. Arcjets were the first electric thrusters to be considered for operational missions. Ling, et al., studied the effect of arcjet plumes on propagation. Arcjets produce a lightly ionized plume and Ling's analysis predicted that the plume would have a negligible effect on communication. Plumes from the higher performance ion thrusters being developed exhibit higher ionization levels, plasma temperatures and particle velo@ities than arcjets. Therefore, there was a need to assess the impact due to these plumes. To address this need, the authors designed and performed a series of experiments to examine propagation effects of plumes. The challenge with these experiments was that they had to be performed in the operational environment of the thruster. Therefore, the experiments were conducted inside a metal chamber which could be depressurized to simulate a near vacuum condition of space. The metal chamber presents a potential large source of error to the propagation measurements due to the corruption of the desired data by multiple wall reflections within the chamber. This chamber effect was minimized by employing a pulsed-continuous wave transmitter and receiver system. This system, based on an HP8510 Network Analyzer, uses external hardware time gating to eliminate the clutter of the spurious reflections. Additionally, high gain antennas were used in the measurements to ensure that minimal amounts of energy ",ere transmitted/received in undesirable directions. The measurements took place in Vacuum Facility 5 of the Electric Propulsion Laboratory at the NASA Glenn Research Center. This facility utilizes a cylindrical, stainless steel, vacuum chamber, which is 18.3 m long and 4.6 m in diameter. For the tests being described here a 30 cm diameter, xenon ion thruster was used. The thruster provided between 500 W and 2.3 kW of operating power. The thruster was mounted on a stand along the axis of the chamber near one of its ends.

Zaman, Afroz J.↗
NASA NTRS2015

Plume Collection Strategies for Icy World Sample Return

Three icy worlds in the solar system display evidence of pluming activity. Water vapor and ice particles emanate from cracks near the south pole of Saturn's moon Enceladus. The plume gas contains simple hydrocarbons that could be fragments of larger, more complex organics. More recently, observations using the Hubble and Herschel space telescopes have hinted at transient water vapor plumes at Jupiter's moon Europa and the dwarf planet Ceres. Plume materials may be ejected directly from possible sub-surface oceans, at least on Enceladus. In such oceans, liquid water, organics, and energy may co-exist, making these environments habitable. The venting of habitable ocean material into space provides a unique opportunity to capture this material during a relatively simple flyby mission and return it to Earth. Plume collection strategies should enable investigations of evidence for life in the returned samples via laboratory analyses of the structure, distribution, isotopic composition, and chirality of the chemical components (including biomolecules) of plume materials. Here, we discuss approaches for the collection of dust and volatiles during flybys through Enceladus' plume, based on Cassini results and lessons learned from the Stardust comet sample return mission. We also highlight areas where sample collector and containment technology development and testing may be needed for future plume sample return missions.

Stardust Collector↗
NASA NTRS1995

Exhausted Plume Flow Field Prediction Near the Afterbody of Hypersonic Flight Vehicles in High Altitudes

A two-dimensional computer code to solve the Burnett equations has been developed which computes the flow interaction between an exhausted plume and hypersonic external flow near the afterbody of a flight vehicle. This Burnett-2D code extends the capability of Navier-Stokes solver (RPLUS2D code) to include high-order Burnett source terms and slip-wall conditions for velocity and temperature. Higher-order Burnett viscous stress and heat flux terms are discretized using central-differencing and treated as source terms. Blocking logic is adopted in order to overcome the difficulty of grid generation. The computation of exhaust plume flow field is divided into two steps. In the first step, the thruster nozzle exit conditions are computed which generates inflow conditions in the base area near the afterbody. Results demonstrated that at high altitudes, the computations of nozzle exit conditions must include the effects of base flow since significant expansion exists in the base region. In the second step, Burnett equations were solved for exhaust plume flow field near the afterbody. The free stream conditions are set at an altitude equal to 80km and the Mach number is equal to 5.0. The preliminary results show that the plume expansion, as altitude increases, will eventually cause upstream flow separation.

Chou, Lynn Chen↗
NASA NTRS2007

Aerosol Source Plume Physical Characteristics from Space-based Multiangle Imaging

Models that assess aerosol effects on regional air quality and global climate parameterize aerosol sources in terms of amount, type, and injection height. The multiangle imaging spectroradiometer (MISR) aboard NASA's Terra satellite retrieves total column aerosol optical thickness (AOT), and aerosol type over cloud-free land and water. A stereo-matching algorithm automatically retrieves reflecting-layer altitude wherever clouds or aerosol plumes have discernable spatial contrast, with about 500-m accuracy, at 1.1-km horizontal resolution. Near-source biomass burning smoke, volcanic effluent, and desert dust plumes are observed routinely, providing information about aerosol amount, particle type, and injection height useful for modeling applications. Compared to background aerosols, the plumes sampled have higher AOT, contain particles having expected differences in Angstrom exponent, size, single-scattering albedo, and for volcanic plume and dust cloud cases, particle shape. As basic thermodynamics predicts, thin aerosol plumes lifted only by regional winds or less intense heat sources are confined to the boundary layer. However, when sources have sufficient buoyancy, the representative plumes studied tend to concentrate within discrete, high-elevation layers of local stability; the aerosol is not uniformly distributed up to a peak altitude, as is sometimes assumed in modeling. MISR-derived plume heights, along with meteorological profile data from other sources, make it possible to relate radiant energy flux observed by the moderate resolution imaging spectroradiometer (MODIS), also aboard the Terra spacecraft, to convective heat flux that plays a major role in buoyant plume dynamics. A MISR climatology of plume behavior based on these results is being developed.

aerosol plumes↗
NASA NTRS2003

A Collimated Retarding Potential Analyzer for the Study of Magnetoplasma Rocket Plumes

A gridded retarding potential analyzer (RPA) has been developed to characterize the magnetized plasma exhaust of the 10 kW Variable Specific Impulse Magnetoplasma Rocket (VX-10) experiment at NASA's Advanced Space Propulsion Laboratory. In this system, plasma is energized through coupling of radio frequency waves at the ion cyclotron resonance (ICR). The particles are subsequently accelerated in a magnetic nozzle to provide thrust. Downstream of the nozzle, the RPA's mounting assembly enables the detector to make complete axial and radial scans of the plasma. A multichannel collimator can be inserted into the RPA to remove ions with pitch angles greater than approximately 1 deg. A calculation of the general collimator transmission as a function over velocity space is presented, which shows the instrument's sensitivity in detecting changes in both the parallel and perpendicular components of the ion energy. Data from initial VX-10 ICRH experiments show evidence of ion heating.

Glover, T. W.↗
NASA NTRS2018

Computational and Experimental Study of Plume and Shock Interaction Effects on Sonic Boom in the NASA Ames 9x7 Supersonic Wind Tunnel

A wind tunnel test was performed in the NASA Ames 9x7 Supersonic Wind Tunnel focusing on the shock waves traveling through and interacting with an exhaust nozzle plume. This experimental study was conducted to develop and validate the CFD capability required to accurately include nozzle flow with impinging shock effects on near field and ground‐propagated sonic boom signatures. The model was made to be generic, and included a simple nozzle shape, two different aft decks, and a few generic horizontal tails. High pressure air was pumped through a nozzle at various nozzle pressure ratios (NPR) to represent the engine plume in flight. The three different aft body representations each created a different shock wave signature that passed through the plume. An aft deck configuration, where part of the aircraft shields the nozzle plume, was also tested. Retroreflective Background-Oriented Schlieren (RBOS) was used to obtain schlieren images of the flow field around the model and behind the model. This study compares wind tunnel data and numerical simulations conducted by the NASA Tetrahedral Unstructured Software System CFD code, USM3D.

Winski, Courtney S.↗
NASA NTRS1991

OPAD through 1991 - Status report no. 2

The Optical Plume Anomaly Detection (OPAD) experimental program has attempted to develop a rocket engine health monitor for the detection, and if possible the quantification, of anomalous atomic and molecular species in exhaust plumes. The test program has formulated instrument designs allowing both wide spectral range and high spectral resolution. Attention is presently given to OPAD data collected for the SSME at NASA-Marshall's technology test stand, with a view to spectral emissions at startup and variations in baseline plume emissions due to changes in rated power level.

Powers, W. T.↗
NASA NTRS2011

Aerodynamic and Aeroacoustic Wind Tunnel Testing of the Orion Spacecraft

The Orion aerodynamic testing team has completed more than 40 tests as part of developing the aerodynamic and loads databases for the vehicle. These databases are key to achieving good mechanical design for the vehicle and to ensure controllable flight during all potential atmospheric phases of a mission, including launch aborts. A wide variety of wind tunnels have been used by the team to document not only the aerodynamics but the aeroacoustic environment that the Orion might experience both during nominal ascents and launch aborts. During potential abort scenarios the effects of the various rocket motor plumes on the vehicle must be accurately understood. The Abort Motor (AM) is a high-thrust, short duration motor that rapidly separates Orion from its launch vehicle. The Attitude Control Motor (ACM), located in the nose of the Orion Launch Abort Vehicle, is used for control during a potential abort. The 8 plumes from the ACM interact in a nonlinear manner with the four AM plumes which required a carefully controlled test to define the interactions and their effect on the control authority provided by the ACM. Techniques for measuring dynamic stability and for simulating rocket plume aerodynamics and acoustics were improved or developed in the course of building the aerodynamic and loads databases for Orion.

Ross, James C.↗
DOE OSTI2026

A lumped particle direct simulation Monte-Carlo method combined with the collisional-radiative model for simulations of non-equilibrium laser-induced plasma plumes

Collisional plasma plumes induced by laser irradiation of material targets exhibit large variations in local density as well as ionization and excitation states, making purely hydrodynamic or kinetic simulations inaccurate or infeasible. To address this challenge and capture non-equilibrium effects in laser-induced plasma plumes at arbitrary degrees of ionization, we develop a hybrid computational approach that combines the kinetic direct simulation Monte Carlo (DSMC) method with a collisional-radiative model (CRM). This ℓDSMC-CRM approach utilizes a lumped particle method to represent minor fractions of excited ions in particle-based simulations and a special coarse-graining technique for atomic spectra and photoionization rates, ensuring numerical convergence at reduced computational cost. The hybrid approach is applied to simulate spatially homogeneous relaxation as well as one- and two-dimensional expansions of plasma plumes induced by irradiation of a copper target by a nanosecond laser pulse in a vacuum or background gas. The comparison with an equilibrium model, where local Saha-Boltzmann equilibrium is enforced, shows that the non-equilibrium effects play a dominant role. The equilibrium model can fail to predict the flow structure and strongly underestimate the degree of absorption of laser radiation by the plume. The ℓDSMC-CRM approach is validated against experimental data demonstrating reasonable agreement with the experimental electron density and temperature, while the equilibrium model is found to dramatically underestimate electron density and temperature. The flexibility of the ℓDSMC-CRM approach allows for its seamless integration into existing DSMC frameworks, making it a valuable tool for high-fidelity plasma modeling in laser-material interactions, laser-based manufacturing, and beyond.

97 MATHEMATICS AND COMPUTING↗
NASA NTRS2005

Experiment to Characterize Aircraft Volatile Aerosol and Trace-Species Emissions (EXCAVATE)

The Experiment to Characterize Aircraft Volatile and Trace Species Emissions (EXCAVATE) was conducted at Langley Research Center (LaRC) in January 2002 and focused upon assaying the production of aerosols and aerosol precursors by a modern commercial aircraft, the Langley B757, during ground-based operation. Remaining uncertainty in the postcombustion fate of jet fuel sulfur contaminants, the need for data to test new theories of particle formation and growth within engine exhaust plumes, and the need for observations to develop air quality models for predicting pollution levels in airport terminal areas were the primary factors motivating the experiment. NASA's Atmospheric Effects of Aviation Project (AEAP) and the Ultra Effect Engine Technology (UEET) Program sponsored the experiment which had the specific objectives of determining ion densities; the fraction of fuel S converted from S(IV) to S(VI); the concentration and speciation of volatile aerosols and black carbon; and gas-phase concentrations of long-chain hydrocarbon and PAH species, all as functions of engine power, fuel composition, and plume age.

Anderson, B. E.↗