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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 955 records · Page 53
All sourcesNASA NTRSDOE OSTI
NASA NTRS2018

Validation of a CFD Model Predicting the Effect of High Level Lateral Acceleration Sloshing on the Heat Transfer and Pressure Drop in a Small-Scale Tank in Normal Gravity

A two-phase CFD model is developed to study the effects of sloshing with high level lateral acceleration on the heat transfer and pressure drop in a small scale tank. Computational results are compared to the data provided by a non-isothermal sloshing experiment without phase change conducted by T. Himeno et al. at the University of Tokyo and JAXA in 2011. The results of the current model are, also, compared to CFD predictions reported by Himeno et al. A step change in lateral acceleration was applied in the experiment. Different levels of lateral acceleration amplitude, varying between 0G and 0.5G, were considered. CFD results for interface movement and tank pressure are presented and compared in this paper to the experimental data for the case in which the value of lateral acceleration was set to 0.5G. The effects of initial and boundary conditions and turbulence modeling approach on the tank pressure change during sloshing are discussed in detail. The effect of conjugate heat transfer in the tank wall is also studied to show its important role in determining the tank pressure evolution. The results of the Reynolds Averaged Navier Stokes (RANS) models are compared to the results of the Large Eddy Simulation model (LES) to underscore the importance of correctly capturing the effects of turbulence for high fidelity predictions.

multiphase flow↗
NASA NTRS2018

Validation of A CFD Model Predicting the Effect of High Level Lateral Acceleration Sloshing on the Heat Transfer and Pressure Drop in A Small-Scale Tank in Normal Gravity

A two-phase CFD model is developed to study the effects of sloshing with high level lateral acceleration on the heat transfer and pressure drop in a small scale tank. Computational results are compared to the data provided by a non-isothermal sloshing experiment without phase change conducted by T. Himeno et al. at the University of Tokyo and JAXA in 2011 [1]. The results of the current model are, also, compared to CFD predictions reported by Himeno et al. [2]. A step change in lateral acceleration was applied in the experiment. Different levels of lateral acceleration amplitude, varying between 0G and 0.5G, were considered. CFD results for interface movement and tank pressure are presented and compared in this paper to the experimental data for the case in which the value of lateral acceleration was set to 0.5G. The effects of initial and boundary conditions and turbulence modeling approach on the tank pressure change during sloshing are discussed in detail. The effect of conjugate heat transfer in the tank wall is also studied to show its important role in determining the tank pressure evolution. The results of the Reynolds Averaged Navier Stokes (RANS) models are compared to the results of the Large Eddy Simulation model (LES) to underscore the importance of correctly capturing the effects of turbulence for high fidelity predictions.

multiphase flow↗
NASA NTRS1998

System and method for controlling the phase of an antenna array

A system and method for controlling power transferred to an aircraft. The system includes a master antenna and a plurality of slave antennas on the ground. Each slave antenna transmits an uplink signal of a unique phase modulated frequency. The master antenna transmits a master uplink signal. The aircraft receives all the uplink signals and modulates a composite of those signals to produce a downlink beacon that has multiple phase components, each of which corresponds to one of the slave antennas and has a unique frequency. Each of the slave antennas receives the downlink beacon and uses the corresponding phase component to adjust the phase of the slave uplink signal relative to the master uplink signal.

Conroy, Bruce↗
NASA NTRS2002

ASTROCULTURE(tm) Commercial Plant Growth Unit and Glove Box Insert

Two commercial plant investigations will be conducted during the STS-107 mission: living flower essential oil production and gene transfer. The research will be done using the ASTROCULTURE (trademark) hardware, which builds on similar experiments flown in the past on the space shuttle. This research will investigate how microgravity might affect the formation of the volatile chemical compounds - the essential oils - produced by two different types of living flowers. The flowers will be cultured in the ASTROCULTURE (trademark) plant chamber, which provides an enclosed and controlled environment. As the flowers bloom in space, they will produce essential oils, and these volatile compounds will be collected using International Flavors and Fragrance's proprietary Solid Phase Micro Extraction (SPME) technology. The gene transfer experiment examines a newly developed transformation system to see if it operates efficiently in the microgravity environment. This research is important for the development of genetically engineered crops, also known as transgenic crops.

Wei-Jia Zhou↗
NASA NTRS1988

Designing Estimator/Predictor Digital Phase-Locked Loops

Signal delays in equipment compensated automatically. New approach to design of digital phase-locked loop (DPLL) incorporates concepts from estimation theory and involves decomposition of closed-loop transfer function into estimator and predictor. Estimator provides recursive estimates of phase, frequency, and higher order derivatives of phase with respect to time, while predictor compensates for delay, called "transport lag," caused by PLL equipment and by DPLL computations.

Statman, J. I.↗
DOE OSTI2020

High-temperature oxidation of transient-liquid phase bonded Ni-based alloys in 1 bar and 250 bar carbon dioxide

Compact microchannel heat exchanger designs for supercritical CO 2 power cycles are valued for equipment size reduction and increased heat transfer. They can be fabricated via transient-liquid phase (TLP) bonding, which utilizes a lower melting point interlayer for bonding facilitation of etched thin plates. Haynes 230 and 282 TLP bonded stacks were exposed to high-purity CO 2 at 1 bar/700 °C to 4000 h and 250 bar/720 °C (supercritical) to 1500 h. All samples obeyed parabolic kinetics after an oxide buildup stage of 500-1000 h. Mass gains were similar for the base and TLP bonded alloys, and oxide thicknesses and scales did not significantly differ around the TLP bond regions. Furthermore, there were some slight oxide compositional differences for the H282 TLP samples at 250 bar. There was a slight pressure effect on mass gain, as samples exposed at the higher pressure experienced higher initial mass gains, but then slower continued oxide growth.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Electronic structure, and magnetic and superconducting pairing tendencies of the alternating single layer–bilayer stacking nickelate La 5 ⁢Ni 3 ⁢O 11 under pressure

Nickelates have continued to surprise since their unconventional superconductivity was discovered. Recently, the layered nickelate La 5 ⁢Ni 3 ⁢O 11 with hybrid single-layer and bilayer stacking showed superconductivity under high pressure. This compound combines features of single-layer La 2 ⁢NiO 4 and bilayer La 3 ⁢Ni 2 ⁢O 7 , but its pairing mechanism remains to be understood. Motivated by this finding, here we report a comprehensive theoretical study of this system. Our density functional theory calculations reveal that the undistorted P4/mmm phase without pressure is unstable due to three distortion modes. As pressure increases, these modes are suppressed, leading to the high-symmetry P4/mmm phase without NiO 6 octahedron tilting. Moreover, the “charge transfer” between the single-layer and bilayer sublattices was observed, leading to hole doping in the single-layer blocks. Our random-phase approximation calculations indicate a leading 𝑑 𝑥 2 −𝑦 2 -wave pairing state that arises from spin-fluctuation scattering between Fermi surface states mainly originating from the single-layer blocks and additional weaker contributions from the bilayer blocks. These spin fluctuations could be detected by inelastic neutron scattering as a strong peak at 𝐪 = (𝜋,𝜋). Our findings distinguish La 5 ⁢Ni 3 ⁢O 11 from other nickelate superconductors discovered so far and the high-𝑇 𝑐 cuprates. We also discuss both similarities and differences between La 5⁢ Ni 3 ⁢O 11 and other hybrid stacking nickelates.

Zhang, Yang [Univ. of Tennessee, Knoxville, TN (Un↗
NASA NTRS1984

Mechanism for forming hydrogen chloride and sodium sulfate from sulfur trioxide, water, and sodium chloride

A molecular orbital study of sodium sulfate and hydrogen chloride formation from sulfur trioxide, water, and sodium chloride shows no activation barrier, in agreement with recent experimental work of Kohl, Fielder, and Stearns. Two overall steps are found for the process. First, gas-phase water reacts with sulfur trioxide along a pathway involving a linear O-H-O transition state yielding closely associated hydroxyl and bisulfite which rearrange to become a hydrogen sulfate molecule. Then the hydrogen sulfate molecule transfers a hydrogen atom to a surface chloride in solid sodium chloride while an electron and a sodium cation simultaneously transfer to yield sodium bisulfate and gas-phase hydrogen chloride. This process repeats. Both of these steps represent well-known reactions for which mechanisms have not been previously determined.

Anderson, A. B.↗
NASA NTRS1975

Space shuttle orbital maneuvering engine platelet injector program

A platelet face injector for the Orbit Maneuvering Engine (OME) on the space shuttle was evaluated as a means of obtaining additional design margin and lower cost. The program was conducted in three phases. The first phase evaluated single injection elements, or unielements; it involved visual flow studies, mixing experiments using propellant simulants, and hot firings to assess combustion efficiency, chamber wall compatibility, and injector face temperatures. In the second phase, subscale units producing 600 lbf thrust were used to further evaluate the orifice patterns chosen on the basis of unielement testing. In addition to combustion efficiency, chamber and injector heat transfer, the subscale testing provided a preliminary indication of injector stability. Full scale testing of the selected patterns at 6,000 lbf thrust was performed in the third phase. Performance, heat transfer, and combustion stability were evaluated over the anticipated range of OMS operating conditions. The effects on combustion stability of acoustic cavity configuration, including cavity depth, open area, inlet contour, and other parameters, were investigated.

Source record↗
DOE OSTI2020

Emergent electric field control of phase transformation in oxide superlattices

Electric fields can transform materials with respect to their structure and properties, enabling various applications ranging from batteries to spintronics. Recently electrolytic gating, which can generate large electric fields and voltage-driven ion transfer, has been identified as a powerful means to achieve electric-field-controlled phase transformations. The class of transition metal oxides provide many potential candidates that present a strong response under electrolytic gating. However, very few show a reversible structural transformation at room-temperature. Here, we report the realization of a digitally synthesized transition metal oxide that shows a reversible, electric-field-controlled transformation between distinct crystalline phases at room-temperature. In superlattices comprised of alternating one-unit-cell of SrIrO 3 and La 0.2 Sr 0.8 MnO 3 , we find a reversible phase transformation with a 7% lattice change and dramatic modulation in chemical, electronic, magnetic and optical properties, mediated by the reversible transfer of oxygen and hydrogen ions. Strikingly, this phase transformation is absent in the constituent oxides, solid solutions and larger period superlattices. Our findings open up this class of materials for voltage-controlled functionality.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Investigations of room temperature multiferroic and magneto-electric properties of (1-Φ) PZTFT-Φ CZFMO particulate composites

Multiferroic composites consisting of a single-phase multiferroic [0.6(PbZr 0.53 Ti 0.47 O 3 )-0.4(PbFe 0.5 Ta 0.5 )O 3 ] as a matrix and a magnetostrictive phase (Co 0.6 Zn 0.4 Fe 1.7 Mn 0.3 O 4 ) dispersed in the matrix are fabricated via hybrid synthesis technique. The structure and surface morphology studies using x-ray diffraction and field emission scanning electron microscopy techniques indicate the formation of 3-0 type particulate composites. Coexistence of soft-magnetic behavior and ferroelectric characteristics are confirmed for composites from magnetization vs magnetic field (M–H) and polarization vs electric field (P–E) measurements, respectively. Magneto-dielectric (MD) measurement shows significant changes in the dielectric properties with the application of a magnetic field, indicating the existence of strong MD behavior. The biquadratic nature of magneto-electric (ME) coupling is described by the Landau free energy equation arising from the strain transfer at the interfaces between the constituent phases. The direct magneto-electric voltage coefficient measurement also confirms very strong coupling between ferroelectricity and magnetism and supports the strain-mediated magneto-electric effect in composites. The Φ = 0.3 composite exhibits the maximum ME coefficient of 20.72 mV/cm Oe with M S = 24.62 emu/g, H C = 59.66 Oe, and piezoelectric coefficient value d 33 = 19 pC/N. In conclusion, the strong magneto-electric effect along with low dielectric loss at room temperature in these composites suggests their suitability for multifunctional magneto-electric device applications such as magnetic sensors, etc.

36 MATERIALS SCIENCE↗
NASA NTRS1996

Common View Time Transfer Using Worldwide GPS and DMA Monitor Stations

Analysis of the on-orbit Navstar clocks and the Global Positioning System (GPS) monitor station reference clocks is performed by the Naval Research Laboratory using both broadcast and postprocessed precise ephemerides. The precise ephemerides are produced by the Defense Mapping Agency (DMA) for each of the GPS space vehicles from pseudo-range measurements collected at five GPS and at five DMA monitor stations spaced around the world. Recently, DMA established an additional site co-located with the US Naval Observatory precise time site. The time reference for the new DMA site is the DoD Master Clock. Now, for the first time, it is possible to transfer time every 15 minutes via common view from the DoD Master Clock to the 11 GPS and DMA monitor stations. The estimated precision of a single common-view time transfer measurement taken over a 15-minute interval was between 1.4 and 2.7 nanoseconds. Using the measurements from all Navstar space vehicles in common view during the 15-minute interval, typically 3-7 space vehicles, improved the estimate of the precision to between 0.65 and 1.13 nanoseconds. The mean phase error obtained from closure of the time transfer around the world using the 11 monitor stations and the 25 space vehicle clocks over a period of 4 months had a magnitude of 31 picoseconds. Analysis of the low noise time transfer from the DoD Master Clock to each of the monitor stations yields not only the bias in the time of the reference clock, but also focuses attention on structure in the behaviour of the reference clock not previously seen. Furthermore, the time transfer provides a a uniformly sampled database of 15-minute measurements that make possible, for the first time, the direct and exhaustive computation of the frequency stability of the monitor station reference clocks. To lend perspective to the analysis, a summary is given of the discontinuities in phase and frequency that occurred in the reference clock at the Master Control Station during the period covered by the analysis.

Reid, Wilson G.↗
NASA NTRS1983

Ionospheric limitations to time transfer by satellite

The ionosphere can contribute appreciable group delay and phase change to radio signals traversing it; this can constitute a fundamental limitation to the accuracy of time and frequency measurements using satellites. Because of the dispersive nature of the ionosphere, the amount of delay is strongly frequency-dependent. Ionospheric compensation is necessary for the most precise time transfer and frequency measurements, with a group delay accuracy better than 10 nanoseconds. A priori modeling is not accurate to better than 25%. The dual-frequency compensation method holds promise, but has not been rigorously experimentally tested. Irregularities in the ionosphere must be included in the compensation process.

Knowles, S. H.↗
DOE OSTI2024

Direct extraction of lithium from ores by electrochemical leaching

With the rapid increase in lithium consumption for electric vehicle applications, its price soared during the past decade. To secure a reliable and cost-effective supply chain, it is critical to unlock alternative lithium extraction resources beyond conventional brine. In this study, we develop an electrochemical method to directly leach lithium from α-phase spodumene. We find the H 2 O 2 promoter can significantly reduce the leaching potential by facilitating the electron transfer and changing the reaction path. Upon leaching, β-phase spodumene shows a typical phase transformation to HAlSi 2 O 6 , while leached α-phase remains its original crystal phase with a lattice shrinkage. To demonstrate the scale-up potential of electrochemical leaching, we design a catalyst-modified high-throughput current collector for high loading of suspended spodumene, achieving a leaching current of 18 mA and a leaching efficiency of 92.2%. Electrochemical leaching will revolutionize traditional leaching and recycling processes by minimizing the environmental footprint and energy consumption.

25 ENERGY STORAGE↗
NASA NTRSDate not supplied

Acoustic Insights into Flow Condensation Mechanisms

Two-phase thermal management systems, with both boiling and condensation processes, offer great potential and heat transfer coefficients that are orders of magnitude higher than traditional single-phase systems. However, two-phase flows can suffer from a wide range of interfacial instabilities leading to significant thermal performance degradation. In this study, we aim to detect regime transitions and characterize dominating physical mechanisms of flow condensation, such as turbulent diffusion in annular liquid film and interfacial waves, using an integrated system of acoustic, modal, and optical sensing techniques and thermofluidic characterizations. A wideband acoustic emissions sensor and high-sensitivity accelerometer are utilized to capture acoustic and vibrational signatures that signal the onset of liquid film formation and interfacial waves during flow pattern transitions. Compared to optical imaging, wideband acoustic emission sensing allows for higher sampling rates to capture high-frequency interface oscillations critical to the flow regime transitions and works well even for condensation in opaque tubes. Acoustic features (e.g., amplitude, frequency, energy, duration) are correlated with thermofluidic processes (e.g., capillary flows, turbulent flows, boiling, condensation). By relating thermal performance metrics with these dynamic signatures in acoustic and modal regimes, we explore the ability to probe and monitor critical flow regime transitions and transport efficiency in flow condensation.

Acoustic Modal Regimes↗
NASA NTRSDate not supplied

Orion Power Transfer: Impacts of a Battery-on-Bus Power System Architecture

The Orion Multi-Purpose Crew Vehicle (MPCV) has the capability to transfer power to a co-manifested payload (CPL) during transit from low-Earth orbit to the lunar vicinity. This paper discusses a time-phased parametric power analysis to determine the Orion power transfer capability limit. Charge and discharge curves were generated for various power transfer conditions and measured against various minimum system voltage limits. The Orion electrical power system (EPS) utilizes an unregulated bus architecture, which has important implications when the system is operating under very high load demand conditions, such as during power transfer. This analysis highlights three important effects of this architecture. First, increasing load demand decreases the maximum state of charge (SOC) the batteries can reach when charging. Second, increasing load demand also decreases the allowable battery depth of discharge. These two together can significantly reduce the effective useable capacity of the batteries. Finally, low battery voltage decreases the power generation of the solar arrays. This can lead to significantly longer recharge times or even push the system out of energy balance. These effects have important implications for mission design and vehicle operations and must be accounted for when conducting sizing and design of an unregulated spacecraft EPS.

Electrical Power System↗
DOE OSTI2021

Natural Charge-Transfer Analysis: Eliminating Spurious Charge-Transfer States in Time-Dependent Density Functional Theory via Diabatization, with Application to Projection-Based Embedding

For many types of vertical excitation energies, linear-response time-dependent density functional theory (LR-TDDFT) offers a useful degree of accuracy combined with unrivaled computational efficiency, although charge-transfer excitation energies are often systematically and dramatically underestimated, especially for large systems and those that contain explicit solvent. As a result, low energy electronic spectra of solution-phase chromophores often contain tens to hundreds of spurious charge-transfer states, making LR-TDDFT needlessly expensive in bulk solution. More nefariously, intensity borrowing by the low-energy charge-transfer states can affect intensities of the valence excitations even if those excitation energies are accurate. At higher excitation energies, it is difficult to distinguish spurious CT states from genuine charge-transfer-to-solvent (CTTS) excitations. In this work, we introduce an automated diabatization scheme that enables fast and effective screening of the CTTS acceptor space in bulk solution. Our procedure introduces the concept of “natural charge-transfer orbitals”, which provide a means to isolate characteristic pairs of orbitals that are most likely to participate in a CTTS excitation. The projection of these orbitals onto solvent-centered virtual orbitals provides a criterion for defining the most important solvent molecules in a given excitation. We apply this method to analyze an ab initio molecular dynamics (MD) trajectory of I-(aq) and report the lowest-energy CTTS band in the absorption spectrum. Our results are in excellent agreement with experimental measurements for bulk I-(aq), and only one-third of the water molecules in the I-(H2O)96 simulation cell need to be described with LR-TDDFT in order to obtain excitation energies that are converged to < 0.1 eV. The tools introduced herein will improve the accuracy, efficiency, and usability of LR-TDDFT in solution-phase environments

Carter-Fenk, Kevin D.↗
NASA NTRSDate not supplied

Flow Boiling & Condensation Experiment (FBCE): Flow Boiling in Earth Gravity and Onboard the International Space Station

Two phase thermal management systems that capitalize on both latent and sensible heats of the working fluid can yield orders of magnitude enhancements in flow boiling and condensation heat transfer coefficients and reduce size and weight of future space systems. Because the understanding of microgravity influences on two-phase flow and heat transfer is quite limited, there is presently an urgent need for a new experimental microgravity facility to enable investigators to perform long-duration flow boiling and condensation experiments in pursuit of reliable databases. This presentation will discuss results from the Flow Boiling and Condensation Experiment (FBCE), a collaborative effort between Purdue University and NASA Glenn Research Center. Experiments have been performed using the final system with the Flow Boiling Module (FBM) in vertical orientation in Earth gravity (Mission Sequence Tests, MST) and in microgravity onboard the International Space Station (ISS). High-speed-video flow visualization, heat transfer, and critical heat flux (CHF) results from the MST are presented for both subcooled liquid and saturated liquid-vapor inlet conditions. CHF predictions made using the Interfacial Lift-off Model are compared with a consolidated database made by compiling FBM datasets obtained in prior years for different orientations in Earth gravity and on parabolic flights. New explicit correlations for CHF and subcooled flow boiling heat transfer coefficient are developed and shown to be excellent in their predictive accuracies against consolidated experimental databases. Computations are performed for flows in microgravity and horizontal flows in Earth gravity, the results of which show a good predictive accuracy for both void fraction and wall temperature. Finally, similar preliminary results from the recent ISS experiments are presented.

Issam Mudawar↗