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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 1,189 records · Page 66
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Great Lakes O shore Wind Project: Utility and Regional Integration Study

This project aims to identify transmission system upgrades needed to facilitate offshore wind projects as well as operational impacts of offshore generation on operation of the regional transmission system in the Great Lakes region. A simulation model of the US Eastern Interconnection was used as the test system as a case study for investigating the impact of the integration of a 1000MW offshore wind farm operating in Lake Erie into FirstEnergy/PJM service territory. The findings of this research provide recommendations on offshore wind integration scenarios, the locations of points of interconnection, wind profile modeling and simulation, and computational methods to quantify performance, along with operating changes and equipment upgrades needed to mitigate system performance issues introduced by an offshore wind project.

17 WIND ENERGY↗
DOE OSTI2017

Optimizing and Quantifying CO 2 Storage Resource in Saline Formations and Hydrocarbon Reservoirs

In an effort to reduce carbon dioxide (CO 2 ) emissions from large stationary sources, carbon capture and storage (CCS) is being investigated as one approach. This work assesses CO 2 storage resource estimation methods for deep saline formations (DSFs) and hydrocarbon reservoirs undergoing CO 2 enhanced oil recovery (EOR). Project activities were conducted using geologic modeling and simulation to investigate CO 2 storage efficiency. CO 2 storage rates and efficiencies in DSFs classified by interpreted depositional environment were evaluated at the regional scale over a 100-year time frame. A focus was placed on developing results applicable to future widespread commercial-scale CO 2 storage operations in which an array of injection wells may be used to optimize storage in saline formations. The results of this work suggest future investigations of prospective storage resource in closed or semiclosed formations need not have a detailed understanding of the depositional environment of the reservoir to generate meaningful estimates. However, the results of this work also illustrate the relative importance of depositional environment, formation depth, structural geometry, and boundary conditions on the rate of CO 2 storage in these types of systems. CO 2 EOR occupies an important place in the realm of geologic storage of CO 2 , as it is likely to be the primary means of geologic CO 2 storage during the early stages of commercial implementation, given the lack of a national policy and the viability of the current business case. This work estimates CO 2 storage efficiency factors using a unique industry database of CO 2 EOR sites and 18 different reservoir simulation models capturing fluvial clastic and shallow shelf carbonate depositional environments for reservoir depths of 1219 and 2438 meters (4000 and 8000 feet) and 7.6-, 20-, and 64-meter (25-, 66,- and 209-foot) pay zones. The results of this work provide practical information that can be used to quantify CO 2 storage resource estimates in oil reservoirs during CO 2 EOR operations (as opposed to storage following depletion) and the uncertainty associated with those estimates.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1978

Applications of remote sensing to hydrologic planning

The transfer of LANDSAT remote sensing technology from the research sector to user operational applications requires demonstration of the utility and accuracy of LANDSAT data in solving real problems. This report describes such a demonstration project in the area of water resources, specifically the estimation of non-point source pollutant loads. Non-point source pollutants were estimated from land cover data from LANDSAT images. Classification accuracies for three small watersheds were above 95%. Land cover was converted to pollutant loads for a fourth watershed through the use of coefficients relating significant pollutants to land use and storm runoff volume. These data were input into a simulator model which simulated runoff from average rainfall. The result was the estimation of monthly expected pollutant loads for the 17 subbasins comprising the Magothy watershed.

Loats, H., Jr.↗
NASA NTRS1978

GASP-PL/I Simulation of Integrated Avionic System Processor Architectures

A development study sponsored by NASA was completed in July 1977 which proposed a complete integration of all aircraft instrumentation into a single modular system. Instead of using the current single-function aircraft instruments, computers compiled and displayed inflight information for the pilot. A processor architecture called the Team Architecture was proposed. This is a hardware/software approach to high-reliability computer systems. A follow-up study of the proposed Team Architecture is reported. GASP-PL/1 simulation models are used to evaluate the operating characteristics of the Team Architecture. The problem, model development, simulation programs and results at length are presented. Also included are program input formats, outputs and listings.

Brent, G. A.↗
NASA NTRS1976

Validation of a model for investigating red cell mass changes during weightlessness

The model, both the conceptual model and simulation model, provided a convenient framework on which to demonstrate the commonality between such diverse stresses as descent from altitude, red cell infusions, bed rest, and weightlessness. The results suggest that all of these stresses induce an increased blood hematocrit leading to tissue hyperoxia and eventual inhibition of the erythyocyte producing circuit until the hyperoxic condition is relieved. The erythropoietic system was acting, in these situations, as if it were an hematocrit sensor and regulator. In these terms the decreases in red cell mass during Skylab may be explained in terms of normal feedback regulation of the erythropoietic system in the face of sustained decreases in plasma colume.

Leonard, J. I.↗
NASA NTRS1980

Verification of interim simulated atmospheric turbulence

During horizontal and near-horizontal flight of the space shuttle orbiter, the effects of atmospheric turbulence on the vehicle are crucial in establishing the space shuttle design, control, and human pilot effects. The effects of both turbulent gusts and gust gradients (shears) must be taken into account. By means of a nonrecursive turbulence simulation model, twelve simulated turbulence time series for gusts and gust gradients were generated as part of a previous investigation. The current investigation was concerned with the spectral analysis of the time series based on the use of Fourier transform theory. A comparison between the computed spectra and the corresponding von Karman theoretical spectra is also included. A basic difference is explained between the computed and theoretical spectra which was identified as a result of the comparison. Conclusions and recommendations are presented.

Tatom, F. B.↗
NASA NTRS1981

MLS: Airplane system modeling

Analysis, modeling, and simulations were conducted as part of a multiyear investigation of the more important airplane-system-related items of the microwave landing system (MLS). Particular emphasis was placed upon the airplane RF system, including the antenna radiation distribution, the cabling options from the antenna to the receiver, and the overall impact of the airborne system gains and losses upon the direct-path signal structure. In addition, effort was expended toward determining the impact of the MLS upon the airplane flight management system and developing the initial stages of a fast-time MLS automatic control system simulation model. Results ot these studies are presented.

Thompson, A. D.↗
NASA NTRS1988

A study of carbon monoxide distribution determinations for a global transport model

The primary objective of this grant was to further the development of a global transport/chemistry model that simulates the physico-chemical behavior of methane and carbon monoxide in the troposphere. The computer simulation model is designed to analyze the processes that occur as methane and carbon monoxide are transported from their respective sources to their ultimate fate, e.g., final conversion to CO2, transport to the stratosphere, deposition at ground level, etc.

Peters, Leonard K.↗
NASA NTRS1989

Estimating biogeochemical fluxes across sagebrush-steppe landscapes with Thematic Mapper imagery

Thematic Mapper (TM) satellite data were coupled to an ecosystem simulation model to simulate variation in nitrogen mineralization over time and space in a sagebrush steppe. This system of data inputs and calculations provides estimates of ecosystem properties including rates of biogeochemical processes over extensive and complex landscapes, and under changing management and climatic conditions. The landscape surface was divided into three sagebrush ecosystem types plus one other class consisting of nonsagebrush vegetation. This classification presented a complex mosaic of ecosystem types that shifted markedly in composition from one end of the 933-sq km study area to the other. Annual N-mineralization rates ranged from 5 to 25 kg N/ha among the three sagebrush types. The most active type comprised 42 percent of the entire area but contributed 60 percent to the nitrogen mineralization throughout the landscape.

Reiners, W. A.↗
NASA NTRS1991

Nonlinear influence of mesoscale land use on weather and climate

It is shown that the influence of mesoscale landscape spatial variability on the atmosphere must be parameterized or explicitly modeled in larger-scale atmospheric model simulations including general circulation models. The mesoscale fluxes of heat that result from this variability are shown to be of the same order of magnitude but with a different vertical structure than found for the turbulent fluxes. These conclusions are based on experiments in which no phase changes of water were permitted. To parameterize surface thermal inhomogeneities, the influence of landscape must be evaluated using spectral analysis or an equivalent procedure. To include the nonlinear contribution of each scale, numerical model simulations for the range of observed surface and overlying atmospheric conditions must be performed.

Pielke, R. A.↗
NASA NTRS1992

Identification of time-varying structural dynamic systems - An artificial intelligence approach

An application of the artificial intelligence-derived methodologies of heuristic search and object-oriented programming to the problem of identifying the form of the model and the associated parameters of a time-varying structural dynamic system is presented in this paper. Possible model variations due to changes in boundary conditions or configurations of a structure are organized into a taxonomy of models, and a variant of best-first search is used to identify the model whose simulated response best matches that of the current physical structure. Simulated model responses are verified experimentally. An output-error approach is used in a discontinuous model space, and an equation-error approach is used in the parameter space. The advantages of the AI methods used, compared with conventional programming techniques for implementing knowledge structuring and inheritance, are discussed. Convergence conditions and example problems have been discussed. In the example problem, both the time-varying model and its new parameters have been identified when changes occur.

Glass, B. J.↗
NASA NTRS1991

Initial piloted simulation study of geared flap control for tilt-wing V/STOL aircraft

A simulation study of a representative tilt wing transport aircraft was conducted in 1990 on the Ames Vertical Motion Simulator. This simulation is in response to renewed interest in the tilt wing concept for use in future military and civil applications. For past tilt wing concepts, pitch control in hover and low-speed flight has required a tail rotor or reaction jets at the tail. Use of mono cyclic propellers or a geared flap have also been proposed as alternate methods for providing pitch control at low speed. The geared flap is a subject of this current study. This report describes the geared flap concept, the tilt wing aircraft, the simulation model, the simulation facility and experiment setup, the pilots' evaluation tasks and procedures, and the results obtained from the simulation experiment. The pilot evaluations and comments are also documented in the report appendix.

Guerrero, Lourdes M.↗
NASA NTRS1991

Handling Qualities Results of an Initial Geared Flap Tilt Wing Piloted Simulation

An exploratory simulation study of a novel approach to pitch control for a tilt wing aircraft was conducted in 1990 on the NASA-Ames Vertical Motion Simulator. The purpose of the study was to evaluate and compare the handling qualities of both a conventional and a geared flap tilt wing control configuration. The geared flap is an innovative control concept which has the potential for reducing or eliminating the horizontal pitch control tail rotor or reaction jets required by prior tilt wing designs. The handling qualities results of the geared flap control configuration are presented in this paper and compared to the conventional (programmed flap) tilt wing control configuration. This paper also describes the geared flap concept, the tilt wing aircraft, the simulation model, the simulation facility and experiment setup, and the pilot evaluation tasks and procedures.

Guerrero, Lourdes M.↗
NASA NTRS1997

Extension of a Kolmogorov Atmospheric Turbulence Model for Time-Based Simulation Implementation

The development of any super/hypersonic aircraft requires the interaction of a wide variety of technical disciplines to maximize vehicle performance. For flight and engine control system design and development on this class of vehicle, realistic mathematical simulation models of atmospheric turbulence, including winds and the varying thermodynamic properties of the atmosphere, are needed. A model which has been tentatively selected by a government/industry group of flight and engine/inlet controls representatives working on the High Speed Civil Transport is one based on the Kolmogorov spectrum function. This report compares the Dryden and Kolmogorov turbulence forms, and describes enhancements that add functionality to the selected Kolmogorov model. These added features are: an altitude variation of the eddy dissipation rate based on Dryden data, the mapping of the eddy dissipation rate database onto a regular latitude and longitude grid, a method to account for flight at large vehicle attitude angles, and a procedure for transitioning smoothly across turbulence segments.

McMinn, John D.↗
NASA NTRS2016

First-Order SPICE Modeling of Extreme-Temperature 4H-SiC JFET Integrated Circuits

A separate submission to this conference reports that 4H-SiC Junction Field Effect Transistor (JFET) digital and analog Integrated Circuits (ICs) with two levels of metal interconnect have reproducibly demonstrated electrical operation at 500 C in excess of 1000 hours. While this progress expands the complexity and durability envelope of high temperature ICs, one important area for further technology maturation is the development of reasonably accurate and accessible computer-aided modeling and simulation tools for circuit design of these ICs. Towards this end, we report on development and verification of 25 C to 500 C SPICE simulation models of first order accuracy for this extreme-temperature durable 4H-SiC JFET IC technology. For maximum availability, the JFET IC modeling is implemented using the baseline-version SPICE NMOS LEVEL 1 model that is common to other variations of SPICE software and importantly includes the body-bias effect. The first-order accuracy of these device models is verified by direct comparison with measured experimental device characteristics.

JFET↗
NASA NTRS2020

Modeling the Transport Processes of a Pair of Solar Energetic Particle Events Observed by Parker Solar Probe near Perihelion

We present model calculations of the transport processes of solar energetic particles in the corona and interplanetary medium for two events detected by Parker Solar Probe near its second perihelion on 2019 April 2 and April 4. In the 2019 April 2 event, the <100 keV proton differential intensity measured by the ISOIS EPI-Lo instrument increased by more than a factor of 10 above the pre-event intensity, whereas the ~1 MeV proton differential intensity detected by the EPI-Hi instrument did not show any intensity enhancement. In the 2019 April 4 event, the ~1 MeV proton intensity showed an increase of more than a factor of 100 above the pre-event intensity, but the <100 keV proton intensity enhancement was rather low and gradual. The observational fact that only the 2019 April 4 event displayed a high-energy intensity enhancement indicates that the associated acceleration process in the second event was more energetic than the first event. However, the gradual and low enhancement of the low-energy proton intensity in the second event is at odds with the scenario. In this paper, we investigate the injection and transport processes of protons in the corona and interplanetary magnetic fields with numerical model simulations. Our model calculations suggest that the gradual and low rise of the low-energy protons in the April 4 event was probably due to the different diffusion conditions in these two events and the fact that the spacecraft was moving away from the source region during these two events.

Solar energetic particles↗
NASA NTRSDate not supplied

United States Spacecraft Charging Overview

The United States (US) has a strong history of spacecraft charging studies which predates the first Spacecraft Charging Technology Conference (SCTC) in 1976. Significant progress has been made since the 14th SCTC was held in the Netherlands where the US last presented a country summary to the SCTC. We present here a high-level survey of spacecraft charging work performed since 14th SCTC. Our presentation will include work from the US Space Force, the National Aeronautics and Space Administration (NASA), the Jet Propulsion Laboratory (JPL), Johns Hopkins Applied Laboratory (APL), industry, and academia. We include flight contributions, latest design specifications, ground testing, modeling and simulation, model development, facilities, anomaly study advancement, and various collaborations within the US charging community.

Linda Neergaard Parker↗
NASA NTRSDate not supplied

Initial Validation of a Gas-Granular Flow Solver Using a Subscale, Reduced Pressure Plume Surface Interaction Ground Test

With NASA’s goal to land the next humans on the lunar surface in the next few years, it is vitally important to have a better understanding of the plume surface interaction (PSI) between the landing vehicles and the lunar regolith. The Fluid Dynamics Branch at NASA/MSFC has previously used the gas-granular flow solver Loci/GGFS to qualitatively predict crater formation due to PSI effects in a lunar (near vacuum) ambient environment. In this paper, validation of Loci/GGFS crater width and depth predictions in ambient near-lunar conditions are provided using experimental data collected at MSFC during the Physics-Focused Ground Test 1 (PFGT-1) campaign in 2022. To observe sensitivity to soil models, simulations were conducted with both monodisperse glass bead (MGB) and BP-1 lunar regolith simulant soil models in Loci/GGFS. Crater depth and width comparisons are made with PFGT-1 Run 56, which used BP-1 soil. The Loci/GGFS BP-1 soil model performed slightly better with a mean predicted crater depth within 10% of the experiment. Both soil models predicted crater width within 10%. Cratering occurred more quickly with the MGB soil model. Mesh and spatial order sensitivity are also examined for the BP-1 soil model.

Validation↗