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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 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

RM3 Wave Tank Validation Model

An approximately 1/75th scale point absorber wave energy absorber was built to validate the testing systems of a 16k gallon single paddle wave tank. The model was build based on the RM3 design and incorporated a linear position sensor, a force transducer, and wetness detection sensors. The data set also includes motion tracking data of the device's two bodies acquired from 4x Qualisys cameras. The tank wave spectrum is measured by 4 ultrasonic water height sensors.

16 TIDAL AND WAVE POWER↗
DOE OSTI2020

A Unified View of Topological Phase Transition in Band Theory

We develop a unified view of topological phase transitions (TPTs) in solids by revising the classical band theory with the inclusion of topology. Reevaluating the band evolution from an “atomic crystal” (a normal insulator (NI)) to a solid crystal, such as a semiconductor, we demonstrate that there exists ubiquitously an intermediate phase of topological insulator (TI), whose critical transition point displays a linear scaling between electron hopping potential and average bond length, underlined by deformation-potential theory. The validity of the scaling relation is verified in various two-dimensional (2D) lattices regardless of lattice symmetry, periodicity, and form of electron hoppings, based on a generic tight-binding model. Significantly, this linear scaling is shown to set an upper bound for the degree of structural disorder to destroy the topological order in a crystalline solid, as exemplified by formation of vacancies and thermal disorder. Our work formulates a simple framework for understanding the physical nature of TPTs with significant implications in practical applications of topological materials.

42 ENGINEERING↗
NASA NTRS1984

Propeller aircraft interior noise model utilization study and validation

Utilization and validation of a computer program designed for aircraft interior noise prediction is considered. The program, entitled PAIN (an acronym for Propeller Aircraft Interior Noise), permits (in theory) predictions of sound levels inside propeller driven aircraft arising from sidewall transmission. The objective of the work reported was to determine the practicality of making predictions for various airplanes and the extent of the program's capabilities. The ultimate purpose was to discern the quality of predictions for tonal levels inside an aircraft occurring at the propeller blade passage frequency and its harmonics. The effort involved three tasks: (1) program validation through comparisons of predictions with scale-model test results; (2) development of utilization schemes for large (full scale) fuselages; and (3) validation through comparisons of predictions with measurements taken in flight tests on a turboprop aircraft. Findings should enable future users of the program to efficiently undertake and correctly interpret predictions.

Pope, L. D.↗
NASA NTRS1985

Combined aerodynamic and structural dynamic problem emulating routines (CASPER): Theory and implementation

The Combined Aerodynamic and Structural Dynamic Problem Emulating Routines (CASPER) is a collection of data-base modification computer routines that can be used to simulate Navier-Stokes flow through realistic, time-varying internal flow fields. The Navier-Stokes equation used involves calculations in all three dimensions and retains all viscous terms. The only term neglected in the current implementation is gravitation. The solution approach is of an interative, time-marching nature. Calculations are based on Lagrangian aerodynamic elements (aeroelements). It is assumed that the relationships between a particular aeroelement and its five nearest neighbor aeroelements are sufficient to make a valid simulation of Navier-Stokes flow on a small scale and that the collection of all small-scale simulations makes a valid simulation of a large-scale flow. In keeping with these assumptions, it must be noted that CASPER produces an imitation or simulation of Navier-Stokes flow rather than a strict numerical solution of the Navier-Stokes equation. CASPER is written to operate under the Parallel, Asynchronous Executive (PAX), which is described in a separate report.

Jones, William H.↗
DOE OSTI2023

Scaling for Nuclear Reactor System: Overview

A scaling analysis is essential for predicting the behavior of a reactor system under various operating conditions, as well as for ensuring safe and reliable experimentation and adequate dataset generation for supporting the system code model development and assessment in accordance with USNRC guidelines 1.203. Testing and modeling can be carried out at various scales, from small test units to full-scale reactors, to validate the predictions produced by the analysis. However, due to the cost and challenges associated with full-scale testing, the nuclear industry uses scaled test facilities—integral effect test (IET) and separate effect test (SET)—to identify potential design issues and optimize the design to ensure regulatory compliance for safer operation and anticipated accident management. In general, IET facilities are non-nuclear thermal hydraulics test facilities. In contrast, SET facilities can be non-nuclear testing (e.g., steam generator, containment, pump system SETs) and nuclear testing (mostly fuel-material irradiation testing). IETs are used to study the system-level thermal-hydraulic behavior of the reactor coolant system (RCS) under different anticipated operational occurrences (AOOs) and design basis accidents (DBAs) such as loss-of-coolant-accident (LOCA) and loss-of-power (i.e., station blackout) and loss-of-flow (i.e., failure of RCS pump). Several LOCA scenarios could happen in reactor DBAs, such as main steam line break (MSLB), SG tube rapture (SGTR), break in direct vessel injection (DVI), and other small breaks LOCA. Scaling analysis determines the appropriate size and operating conditions for the test facility. This involves analyzing the system's thermal-hydraulic behavior at different scales and identifying the key parameters that affect the thermal-hydraulic behavior of the reactor. These key parameters can be identified so that the scaled facility can replicate the expected conditions in a prototypical setting. The scaled facility can simulate the same flow rates, pressure gradients, heat transfer coefficients, and fluid properties as the prototype. Scaling analysis is used to ensure that the results from these tests can be scaled up to predict the behavior of a full-scale prototype with an acceptable range of scaling distortions.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
NASA NTRSDate not supplied

Fundamental Test of a Hovering Rotor: Comprehensive Measurements for CFD Validation

A model-scale hover test of a 4-bladed, 11.08-ft diameter rotor was recently completed inside the National Full-Scale Aerodynamics Complex 80- by 120-Foot Wind Tunnel test section. The primary objective of the test was to acquire key experimental data for a hovering rotor of sufficient quality and quantity to allow validation of state-of-the-art analysis codes. A comprehensive measurement set has been acquired, including rotor performance, blade airloads, flow transition locations, blade deflections, and wake geometry for a range of tip Mach numbers and collective settings. The present paper provides an overview of the test, including detailed descriptions of the hardware, instrumentation, and measurement systems. In addition, the specific test objectives, approach, and sample results are presented. The full test database, as well as detailed rotor geometry information, will ultimately be shared openly on a NASA-sponsored website to serve as a benchmark validation dataset.

Hover↗
DOE OSTI2024

Extension of Local Helicity Injection Startup Studies to the Urania Experiment (Final Technical Report)

Initiating high-current plasma in a spherical tokamak (ST) without a central solenoid is a critical issue for the development of the ST configuration. The goal of the research funded through this grant was focused on addressing this challenge by demonstrating scalable startup to high plasma current (I p ), while developing a physical understanding and predictive models for non-solenoidal tokamak plasma startup using Local Helicity Injection (LHI). A major objective of this research and development activity was to use scaling experiments to validate a physics understanding that will support deployment of high-current (~1 MA) startup techniques to fusion-scale facilities such as NSTX-U and beyond.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

CABLE Stage 3 – Ultra‐High Strength/Highly Conductive Al Alloys

This work is to be conducted in support of the CABLE Conductor Manufacturing Prize Program awarded by NREL. The intent is to connect competitor teams with national laboratories that can help accelerate the development of innovative solutions and products. Teams who receive CABLE Prize awards are eligible to utilize vouchers at national laboratories to advance their ideas. NanoAL LLC has been awarded a voucher to utilize at Ames National Laboratory. Ames National Laboratory will perform a scale‐up trial of Nano 6000‐T9 to evaluate and optimize the heat treatment and other processing variables to validate the lab‐scale work done at NanoAL. The final processing schedule will be used to fabricate the submission samples for the Stage 3 contest. All work will be supported by mechanical and electrical conductivity testing be performed by Ames.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Megawatt-Scale Low Temperature Electrolyzer Research Expansion

The development and installation of a flexible low-temperature electrolyzer research capability at the multi-MW scale with integrated renewables will help lower the cost barrier to entry for electrolyzer manufactures needing at scale system and stack evaluation and enable more electrolyzer manufactures to accelerate to commercialization with building block scale demonstration and validation. This NREL capability represents a DOE HFTO investment to support the $1B DOE Clean Hydrogen Electrolysis Program working to achieve the Hydrogen Shot goal of $1 for 1 kg hydrogen in 1 decade, lower greenhouse gas emissions and criteria pollutants, build clean energy infrastructure, and provide pathways to private sector uptake.

Advanced Research on Integrated Energy Systems (AR↗
NASA NTRS1985

Is the Kolmogoroff model applicable to large-scale turbulence?

In view of the present discussion, the Heisenberg-Kolmogoroff (HK) model of turbulence that is often used for turbulent phenomena on all scales is actually valid for a turbulent spectrum wavelength band typically much smaller than the size of the system, and cannot describe phenomena at large scales in astrophysical systems. The results of mixing length theory cannot be accommodated within the HK model's framework without the adoption of an unreasonable coupling constant. It is also noted that the use of the observed velocity-size relationship in molecular clouds with turbulent velocity values of about l to the 1/2-power, within the HK model, gives rise to a growth rate that does not correspond to any known physical processes suspected of operating in molecular clouds.

Canuto, V. M.↗
NASA NTRS2022

Simulation and Scaling of the Turbulent Vertical Heat Transport and Deep-Cycle Turbulence Across the Equatorial Pacific Cold Tongue

Microstructure observations in the Pacific cold tongue reveal that strong turbulence often penetrates into the thermocline producing hundreds of W/m2 of downward heat transport during nighttime and early morning. However, virtually all observations of this deep-cycle turbulence (DCT) are from 0◦N,140◦W. Here, a hierarchy of ocean process simulations including submesoscale-permitting regional models and turbulence-permitting large eddy simulations (LES) embedded in a regional model provide insight into DCT at and beyond 0◦N,140◦W. A regional hindcast quantifies the spatio-temporal variability of subsurface turbulent heat fluxes throughout the cold tongue from 1999-2016. Climatologically, the mean heat flux is strongest (∼100W/m2) within2◦ of the equator. The heat flux is slightly (∼10 W/m2) stronger in the northern than southern hemisphere throughout the cold tongue. The seasonal cycle of the heat flux, which is not everywhere aligned with the surface flux, ranges from 150 W/m2 near the equator to 30 W/m2 and 10 W/m2 at 4◦N and S respectively. Aseasonal variability of turbulent heat fluxes is logarithmically distributed and temporally uncorrelated with surface heat fluxes. The aseasonal variability of turbulence is highlighted in 34-day LES of Boreal autumn at 0◦N and 3◦N,140◦W. Intense DCT occurs frequently above the undercurrent at 0◦N and intermittently at 3◦N. Daily-mean heat fluxes scale with the bulk vertical shear and the wind stress, which together explain ∼90% of the daily variance across both LES. Observational validation of the scaling at 0◦N,140◦W is encouraging, but observations beyond 0◦N,140◦W can facilitate needed refinement of mixing parameterization in ocean models.

Simulation↗
DOE OSTI2025

Separability of microtearing mode and electron temperature gradient turbulence regimes

The separability of microtearing mode (MTM)-dominated and electron temperature gradient (ETG)-driven turbulence regimes is studied with multiscale nonlinear gyrokinetic simulations. The simulations are based on National Spherical Torus Experiment-like, high-confinement mode pedestal parameters, where electromagnetic perturbations are large. Linear analysis indicates a wide scale-separation between the MTM and ETG modes in binormal wavenumber space (perpendicular to the magnetic field line), with no unstable modes at intermediate scales. Likewise, single-scale nonlinear analyses, retaining ion-only or electron-only spatio-temporal scales, produce seemingly well-converged transport states. Surprisingly, the multiscale simulation, which contains both the ion and electron scales, closely follows the transport from the electron-scale simulation. This trend is robust over a wide range of electron temperature gradient. Remarkably, compared to ion-scale simulations, MTM turbulence is significantly reduced at multiscale resolution even when ETG turbulence is low. In this case, traditional ion-scale resolution overestimates the electron energy flux, and it is not possible to accurately simulate the MTM turbulence with separable ion-scale simulations. Here, while the analysis confirms the validity of electron-scale simulations for predicting the electron transport, it also indicates that multiscale simulation may be required for reproducing the turbulence spectrum for systems with coupled MTM-ETG turbulence.

H-mode↗
NASA NTRS2005

Contributions of TRMM to Our Understanding of Precipitation Processes and Climate Variability

The Tropical Rainfall Measuring Mission (TRMM), a joint U.S./Japan effort, has completed seven and a half years in orbit. This successful research mission studying precipitation processes and climatology has also become a key element in the routine monitoring of global precipitation. The package of rain measuring instrumentation, including the first rain radar and microwave radiometer combination in space, continues to function perfectly, and the satellite has the capability to operate for a number of additional years, providing a unique, long-term record of global tropical precipitation characteristics. A summary of research highlights will be presented covering topics ranging over climate analysis, improving forecasts, and storm and precipitation processes. A focus of the talk will be the important role of TRMM data in multi-satellite precipitation analyses at fine time scales and in improving our understanding of the validity of climate-scale variations through comparison with, and eventual improvement of, the GEWEX Global Precipitation Climatology Project (GPCP) 25-year data set.

Adler, Robert F.↗
NASA NTRS2005

Local Scale Radiobrightness Modeling During the Intensive Observing Period-4 of the Cold Land Processes Experiment-1

The NASA Cold Land Processes Field Experiment (CLPX-1) was designed to provide microwave remote sensing observations and ground truth for studies of snow and frozen ground remote sensing, particularly issues related to scaling. CLPX-1 was conducted in 2002 and 2003 in Colorado, USA. One of the goals of the experiment was to test the capabilities of microwave emission models at different scales. Initial forward model validation work has concentrated on the Local-Scale Observation Site (LSOS), a 0.8 ha study site consisting of open meadows separated by trees where the most detailed measurements were made of snow depth and temperature, density, and grain size profiles. Results obtained in the case of the 3& Intensive Observing Period (IOP3) period (Feb., 2003, dry snow) suggest that a model based on Dense Medium Radiative Transfer (DMRT) theory is able to model the recorded brightness temperatures using snow parameters derived from field measurements. This paper focuses on the ability of forward DMRT modelling, combined with snowpack measurements, to reproduce the radiobrightness signatures observed by the University of Michigan s Truck-Mounted Radiometer System (TMRS) at 19 and 37 GHz during the 4th IOP (IOP4) in March, 2003. Unlike IOP3, conditions during IOP4 include both wet and dry periods, providing a valuable test of DMRT model performance. In addition, a comparison will be made for the one day of coincident observations by the University of Tokyo's Ground-Based Microwave Radiometer-7 (GBMR-7) and the TMRS. The plot-scale study in this paper establishes a baseline of DMRT performance for later studies at successively larger scales. And these scaling studies will help guide the choice of future snow retrieval algorithms and the design of future Cold Lands observing systems.

Kim, Edward J.↗
DOE OSTI2021

Oilwell Conversion (Well API 121913310501) to Geothermal Heat Storage Well for Flexible Electricity Storage

Geothermal growth is limited by a lack of geographically dispersed high-temperature thermal resources and high initial upfront investment in characterization and well construction. This project intended to address the challenges of energy supply intermittency and enhance grid resilience, reliability, and energy security by storing energy provided from currently available renewable resources in the subsurface to harvest it a later time during at-peak energy demand. This project intended to improve geothermal adoption, reduce initial project risk, and improve price competitiveness through utilizing existing oil and gas infrastructure such as non-productive wells, non-economic fields, dry holes, and orphaned wells. The project also intended to address the lack of geographically dispersed thermal resources and enhance grid resilience, reliability, and energy security by introducing an economical method for storing energy from currently available renewable resources in the subsurface for usage during at-peak energy demand. During this research, the project furthered the understanding of the feasibility of utilizing abandoned oil and gas wells as geothermal heat storage wells. The project team investigated the heat storage and hydrogeological characteristics of subsurface reservoirs in the Illinois Basin to evaluate their response to heat injection for determining the evolution of temperature profiles and heat losses over time using existing and available data sets. The project team then performed modeling and simulation to evaluate the heat losses of returning fluids during heat extraction. The outputs were used to select an optimal candidate reservoir and location in Southern Illinois. The team designed and performed a small-scale field test in an existing oil well to refine the model and to demonstrate the permitting and regulatory pathways necessary for the conversion of oil and gas assets to geothermal use. The field test also serves as a proof of concept and can guide the procedures for future research and implementation. Additionally, the project team, conducted initial market research and customer discovery to develop a go to market strategy for an Advanced Geothermal Energy Storage (AGES) system. The project team in this research also identified the parameters to be refined in future research, to improve the current go to market strategy economic model. To this end several subject matter experts were also identified to assist in future research with geothermal infrastructure setup, energy storage policy and law, energy storage market demand, potential siting based on demand etc. Future research will involve further sophistication of the site commercial modeling, implementing a larger-scale test, and further refinement of the thermodynamic modeling/simulation process. The output will be lifecycle costs and economics suitable for comparison to alternative approaches from a validated full-scale demonstration for venture capital investment into this technology. The project successfully demonstrated the ability to leverage existing oilfield infrastructure, permits, and land access and leasing agreements, to enable geothermal storage projects to come online faster and cheaper than a greenfield development could. This technology could allow for greater energy independence and security through long-term energy storage solutions. The longer duration allows for greater storage for renewables currently limited by hours-long storage durations of lithium-ion. The AGES system would support the growth of renewable energy farms, and provide greater opportunities for a cleaner energy infrastructure.

15 GEOTHERMAL ENERGY↗
NASA NTRS1987

Uniformly-valid asymptotic solutions to the Orr-Sommerfeld equation using multiple scales

The Orr-Sommerfeld equation is studied using the method of multiple scales. The leading-order uniformly-valid asymptotic solutions are obtained without recourse to heuristic methods for two different types of velocity profiles. Solutions were obtained for arbitrary velocity profiles without inflection or critical points and for profiles with simultaneous inflection and critical points. These are shown to reproduce previously obtained solutions in the inner and outer regions.

Long, Lyle N.↗
NASA NTRS1980

Development of test methods for scale model simulation of aerial applications in the NASA Langley Vortex Research Facility

As part of basic research to improve aerial applications technology, methods were developed at the Langley Vortex Research Facility to simulate and measure deposition patterns of aerially-applied sprays and granular materials by means of tests with small-scale models of agricultural aircraft and dynamically-scaled test particles. Interactions between the aircraft wake and the dispersed particles are being studied with the objective of modifying wake characteristics and dispersal techniques to increase swath width, improve deposition pattern uniformity, and minimize drift. The particle scaling analysis, test methods for particle dispersal from the model aircraft, visualization of particle trajectories, and measurement and computer analysis of test deposition patterns are described. An experimental validation of the scaling analysis and test results that indicate improved control of chemical drift by use of winglets are presented to demonstrate test methods.

Jordan, F. L., Jr.↗