SuperDEM-CFD: Open source parallel solver for non-spherical particle-fluid fluidization systems
Presented by LRST at the AIChE 2020 Annual Meeting, 11/16
Gao, Xi↗
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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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Synthetic apolipoproteins, and related compositions methods and systems for nanolipoprotein particles formation
Synthetic apolipoproteins based on native/naturally occurring homolog proteins can be prepared using solid-phase peptide synthesis approaches combined with native chemical ligation methods to create analogs of full length apolipoproteins. The chemical synthesis is expected to allow introduction of non-natural amino acids, e.g., α,α′-dialkyl amino acids, with a periodicity that encourages both helix formation and amphipathicity. Such apolipoprotein analogs are expected to encourage, in some embodiments, facile and more complete NLP formation, enabling consideration of full spectrum of nanoparticle-based biotechnology applications ranging from therapeutic sequestration and delivery to energy/biofuel production to biopolymer production.
Source record↗
Comparison of drop size distributions from two droplet sizing systems
A comparison between the Phase Doppler Particle Analyzer and the combined measurements from Particle Measuring Systems' Forward Scattering Spectrometer Probe and the Optical Array Probe was conducted in an icing wind tunnel using NASA Icing Research Tunnel spray nozzles to produce the supercooled water droplet cloud. Clouds having a range of volume median diameters from 10 to greater than 50 microns were used for the instrument comparisons. A volume median diameter was calculated from combining the droplet distributions of the Optical Array Probe and the Forward Scattering Spectrometer Probe. A comparison of the combined volume median diameters and the Phase Doppler Particle Analyzer volume median diameters showed agreement from 10 microns up to 30 microns. Typical drop size distributions from the Phase Doppler Particle Analyzer, the Forward Scattering Spectrometer Probe, and Optical Array Probe are presented for several median volume diameters. A comparison of the distributions illustrates regions of the distributions where there is good agreement and other regions where there are discrepancies between the Phase Doppler Particle Analyzer and the Particle Measuring Systems' droplet size instruments.
Oldenburg, John R.↗
The Propagation of Low Energy Charged Particles in the Inner Solar System
Propagation of low energy charged particles in inner solar system
CHARGED PARTICLE↗
Fluorescent particle generation and detection system for validation of sterility maintenance.
Aerosolized bacterial simulating fluorescent particle generation and detection system for sterility maintenance validation in closed system allowing sterile assembly and repair
Adlon, G. L.↗
An improved sulphur hexafluoride gas handling system for a potential drop particle accelerator.
Sulfur hexafluoride gas handling system for potential drop particle accelerator, considering design, fabrication and performance
SULFUR COMPOUND↗
Methods and systems for calibration of particle detectors
Techniques for calibration of particle detectors are disclosed. In one aspect, a system for calibrating a particle detector includes a source configured to emit particles including a first and a second type of particles; a first and a second shielding unit configured to be removably positioned in a travel path of the particles and configured to block at least a portion of the first type of particles and to allow the second type of particles to traverse substantially unimpeded there through; one or more particle detectors positioned in the travel path of the particles to receive particles after traversing through the first or the second shielding unit and produce electronic pulses in response to the detection of the particles; and a processor coupled to the one or more particle detectors to generate training date and a classifier that allows classification of the first and the second types of particles.
47 OTHER INSTRUMENTATION↗
The lifetime of ice particles in the solar system
The behavior of spherical water-ice particles in interplanetary space is investigated theoretically using an equation which gives the sublimation rate as a function of the solar energy distribution at 1 AU, solar distance, the temperature of the ice-particle surface, the temperature of the surrounding background, particle absorption efficiency, particle radius, and the complex refractive index of ice. The variation of sublimation rate with particle size is examined, and it is shown that the sublimation rate depends critically on the absorptivity of ice in the near-IR spectral region. Two different spectral-absorption curves are plotted on the basis of two different choices for the complex refractive index of ice, and an attempt is made to decide experimentally which energy distribution is more appropriate. Results of direct laboratory measurements of the sublimation rate of smooth spherical ice particles are compared with the theoretical results obtained from the cited sublimation-rate equation. Agreement between theory and experiment is found to be excellent when the complex refractive indices given by Bertie et al., (1969) are employed. Sublimation rates and particle lifetimes are then computed as a function of particle radius for heliocentric distances of 0.5, 0.75, and 1.0 AU.
Patashnick, H.↗
Comets produce submicron particles in the solar system
Observational evidence for the existence of submicron particles issuing from meteor streams and comets is examined. The MTS Explorer 46 carried a meteoroid detector which measured the rate of impact of particles with masses on the order of 10 to the -16th gram. Particle enhancements were observed in association with meteor streams, such as the Taurid and Orionids. The ratio of radiation pressure to gravity is employed to examine the effects of radiation pressure on the particles. When the ratio is higher than one, particles become smaller, unless they are dielectrics. Particles with radii less than 0.1 micron, having a potential of +3.3 V, are projected to have a lifetime of about 3 yr. Several thousands of tons of submicron particles are expected to be produced during a cometary perihelion passage. Launch of a long duration exposure facility with the Shuttle is recommended for studies of the decay of the particles over time.
Singer, S. F.↗
Prototype Modeling for a Light-Trapping Planar-Cavity Enclosed Particle Solar Receiver
Concentrating solar thermal (CST) systems present a promising avenue for affordable and reliable energy production. Solar receivers are key components that determine the efficiency and longevity of these systems. Particle-based solar receivers have emerged as a compelling alternative to traditional technologies, offering several advantages that address limitations in current CST systems. This is especially true as next-generation CST technologies target applications including electricity generation, thermochemical processes, and industrial process heat, many of which necessitate higher operating temperatures than current commercial molten salt systems. Molten-salt thermal energy storage (TES) systems, commonly used in CSP, face challenges related to freezing and corrosion. Particle-based TES systems, in contrast, do not experience these issues, as particles are stable at high temperatures, exceeding 1000 degrees Celsius. This capability allows for a wider range of applications, including those requiring higher temperatures for industrial processes and efficient electricity generation. A novel innovation in particle-based solar receiver technology is the light-trapping planar cavity receiver (LTPCR) configuration developed by NREL. The LTPCR design consists of small cavity-like structures using opaque planar surfaces, enabling efficient capture and absorption of solar energy. A high incident flux concentration at the cavity aperture is absorbed on the receiver walls, and subsequently transferred to particles on the inside of cavities. The particles flow through the system, forming a fluidized bed inside of the receiver panels, effectively capturing the absorbed solar heat. Air is used as a fluidizing medium in this process to enhance particle heat transfer and mixing. The effectiveness of this design lies in its ability to manage solar flux conditions and ensure high solar-to-thermal receiver efficiency. A 100-kW prototype is currently being tested at the King Saud University in Saudi Arabia to assess the receiver performance. A range of modeling analyses for the optical, thermal, and mechanical effects were conducted to assess the performance of the receiver under on-sun conditions. The solar flux resulting from the KSU heliostat field was modeled using NREL SolTrace software and produced up to 600 kW/m2 at the receiver aperture. The solar flux absorbed on the receiver walls was then used within a computational fluid dynamics (CFD) model to predict wall temperature distributions along with radiation and convection loss. A two-phase CFD model was developed for the fluidized bed of silica sand inside the receiver panels to predict local wall-to-particle heat transfer coefficients, particle temperature distributions, and outlet temperature of the particles. We have also conducted analyses to understand the thermomechanical behavior of these innovative enclosed light-trapping solar receivers optimized for particle heating. We used finite element analysis (FEA) to predict the receiver's performance using temperature distributions obtained from CFD and based on the resulting stress profiles, evaluated creep-fatigue damage with a goal of achieving a 30-year service life. Analysis showed a significant impact of the particle-to-wall heat transfer coefficients (HTCs) on receiver performance, with higher HTCs resulting in reduced stress and increased lifespan. For instance, when using Inconel 740H, increasing the HTC from 800 W/m2 K to 1400 W/m2 K increased the creep life from 4,000 hours to over 100,000 hours. This highlights the importance of understanding and optimizing heat transfer in the design of high-efficiency receivers.
14 SOLAR ENERGY↗
Explicit high-order non-canonical symplectic particle-in-cell algorithms for Vlasov-Maxwell systems
Not Available
Xiao, Jianyuan↗
Methodology for the Elimination of Reflection and System Vibration Effects in Particle Image Velocimetry Data Processing
A methodology to eliminate model reflection and system vibration effects from post processed particle image velocimetry data is presented. Reflection and vibration lead to loss of data, and biased velocity calculations in PIV processing. A series of algorithms were developed to alleviate these problems. Reflections emanating from the model surface caused by the laser light sheet are removed from the PIV images by subtracting an image in which only the reflections are visible from all of the images within a data acquisition set. The result is a set of PIV images where only the seeded particles are apparent. Fiduciary marks painted on the surface of the test model were used as reference points in the images. By locating the centroids of these marks it was possible to shift all of the images to a common reference frame. This image alignment procedure as well as the subtraction of model reflection are performed in a first algorithm. Once the images have been shifted, they are compared with a background image that was recorded under no flow conditions. The second and third algorithms find the coordinates of fiduciary marks in the acquisition set images and the background image and calculate the displacement between these images. The final algorithm shifts all of the images so that fiduciary mark centroids lie in the same location as the background image centroids. This methodology effectively eliminated the effects of vibration so that unbiased data could be used for PIV processing. The PIV data used for this work was generated at the NASA Langley Research Center Quiet Flow Facility. The experiment entailed flow visualization near the flap side edge region of an airfoil model. Commercial PIV software was used for data acquisition and processing. In this paper, the experiment and the PIV acquisition of the data are described. The methodology used to develop the algorithms for reflection and system vibration removal is stated, and the implementation, testing and validation of these algorithms are presented.
Bremmer, David M.↗
System-size Convergence of Nonthermal Particle Acceleration in Relativistic Plasma Turbulence
We apply collisionless particle-in-cell simulations of relativistic pair plasmas to explore whether driven turbulence is a viable high-energy astrophysical particle accelerator. We characterize nonthermal particle distributions for varying system sizes up to L/2πρ e0 = 163, where L/2π is the driving scale and ρ e0 is the initial characteristic Larmor radius. We show that turbulent particle acceleration produces power-law energy distributions that, when compared at a fixed number of large-scale dynamical times, slowly steepen with increasing system size. We demonstrate, however, that convergence is obtained by comparing the distributions at different times that increase with system size (approximately logarithmically). We suggest that the system-size dependence arises from the time required for particles to reach the highest accessible energies via Fermi acceleration. The converged power-law index of the energy distribution, α ≈ 3.0 for magnetization σ = 3/8, makes turbulence a possible explanation for nonthermal spectra observed in systems such as the Crab Nebula.
Zhdankin, Vladimir↗
Long-range collectivity in small collision systems with two- and four-particle correlations at STAR
New STAR measurements of two- and four-particle (c 2 {4}) azimuthal angle correlations are reported for p+Au collisions at 200 GeV and d+Au collisions from 19.6 to 200 GeV. A negative c 2 {4}, consistent with collective anisotropic flow, is observed in high multiplicity d+Au events at 62.4 and 200 GeV where the statistical significance of the data allows an analysis. A template fitting method, employed to subtract non-flow contributions to the two-particle correlations, allows the extraction of the anisotropy coefficients (ν 2 ) for these systems at their respective energies. The ν 2 results for different energies show a common dependence on the charged particle multiplicity density ( < dN ch /dη > ), which provide important insight on the nature of collective behavior in small collision systems.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Interaction of large, high power systems with operational orbit charged particle environments
Concepts are presently being advanced for space systems to be used for such activities as manufacturing, earth observations, scientific exploration, power generation and human habitation, in locations ranging from low earth orbit (300-500 km) to geosynchronous orbit and beyond. Many of these systems concepts envision large structures and high power levels, and consequently higher operating voltages than have been used in space to date. The potential impact of interactions of space systems with their operational orbit charged particle environments on the systems' performance must be accounted for in the design process. A potentially hazardous spacecraft-environment interaction is discussed, namely the interaction of large high voltage systems with low energy (less than 50 eV) plasmas which can result in loss of power, and/or arcing. The impact of this class of interactions on system operation is most severe at low orbits where the ambient plasmas are densest. Results of experimental work and predictions of simple analytical models are presented and their implications for design of space systems are discussed.
Purvis, C. K.↗
Spectral and Structural Characteristics for Cluster Systems of Charged Brownian Particles
We report on the results of analytic and numerical investigations of the dynamics for bounded ensembles of charged Brownian particles in the potential field of an electrostatic trap. Simulation has been performed for cluster systems consisting of (approximately up to one thousand) particles with the Coulomb interaction in a wide range of their parameters. The spectral structures and structural characteristics of the systems being simulated have been compared. The dependence of the form of the pair correlation function and the size of cluster systems on the temperature and the number of particles has been analyzed. The relation between the spectral density of displacements of the center of mass and of individual particles and the structural characteristics and nonideality parameter of the ensembles being modeled has been investigated.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Near-field radiative heat transfer between irregularly shaped dielectric particles modeled with the discrete system Green's function method
Near-field radiative heat transfer (NFRHT) between irregularly shaped dielectric particles made of SiO 2 and morphology characterized by Gaussian random spheres is studied. Particles are modeled using the discrete system Green's function (DSGF) approach, which is a volume integral numerical method based on fluctuational electrodynamics. This method is applicable to finite, three-dimensional objects, and all system interactions are defined independent of thermal excitation by a generalized system Green's function. The DSGF method is deemed suitable to model NFRHT between irregularly shaped particles after verification against the analytical solution for chains of two and three SiO 2 spheres. The NFRHT results reveal that geometric irregularity in particles leads to a reduction of the total conductance from that of comparable perfect spheres at vacuum separation distances smaller than the particle size, a regime in which NFRHT is a surface phenomenon. At vacuum separation distances larger than the particle size, NFRHT becomes a volumetric process, and the total conductance between irregularly shaped particles converges to that of comparable perfect spheres. Spectral analysis reveals, however, that particle irregularity leads to damping and broadening of resonances at all separation distances, thereby highlighting the importance of the DSGF method for spectral engineering in the near field. The reduced spectral coherence when particle size is larger than the vacuum separation distance is attributed to coupling of surface phonon-polaritons within the randomly generated, distorted particle features. For particle size smaller than the vacuum separation distance, resonance broadening and damping are linked with the multiple localized surface phonon modes supported by the composite spherical harmonic morphologies of the Gaussian random spheres. In conclusion, this paper has direct implications for thermal management of packed particle systems, with applications in radiative property control, electronics, energy conversion, and nanomanufacturing.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗