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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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Rolling Optimization of Transmission Network Recovery and Load Restoration Considering Hybrid Wind-Storage System and Cold Load Pickup

A common solution to deal with the stochasticity introduced by fast-ramping wind power integration is to equip wind farms (WFs) with energy storage systems (ESSs) to formulate hybrid WF-ESSs. In addition to leveling off wind power fluctuations during normal operations, a hybrid WF-ESS can be a flexible power source to accumulate the power system restoration. In this paper, we propose a rolling optimization model for transmission network recovery and load restoration considering the contributions of WF-ESSs. The proposed model is formulated as a mixed integer linear programming problem that simultaneously optimizes the amount and location of restorable load blocks as well as the restoration lines. The cold load pickup features of interrupted loads considering the outage duration are modeled in detail. A chance-constrained method is employed to deal with the uncertainty of wind power, and a rolling horizon-based framework is adopted to reduce the influence of forecast error. Case studies are conducted on both New England 39-bus system and part of a provincial power system in China. The results show that the load restoration process can be significantly accelerated by employing the proposed method and contributions of hybrid WF-ESSs to power system restoration are validated.

chance-constrained optimization↗
NASA NTRS2012

Quality Control Algorithms for the Kennedy Space Center 50-Megahertz Doppler Radar Wind Profiler Winds Database

This paper presents the process used by the Marshall Space Flight Center Natural Environments Branch (EV44) to quality control (QC) data from the Kennedy Space Center's 50-MHz Doppler Radar Wind Profiler for use in vehicle wind loads and steering commands. The database has been built to mitigate limitations of using the currently archived databases from weather balloons. The DRWP database contains wind measurements from approximately 2.7-18.6 km altitude at roughly five minute intervals for the August 1997 to December 2009 period of record, and the extensive QC process was designed to remove spurious data from various forms of atmospheric and non-atmospheric artifacts. The QC process is largely based on DRWP literature, but two new algorithms have been developed to remove data contaminated by convection and excessive first guess propagations from the Median Filter First Guess Algorithm. In addition to describing the automated and manual QC process in detail, this paper describes the extent of the data retained. Roughly 58% of all possible wind observations exist in the database, with approximately 100 times as many complete profile sets existing relative to the EV44 balloon databases. This increased sample of near-continuous wind profile measurements may help increase launch availability by reducing the uncertainty of wind changes during launch countdown

Barbre, Robert E., Jr.↗
DOE OSTI2013

Model Fidelity Study of Dynamic Transient Loads in a Wind Turbine Gearbox: Preprint

Transient events cause high loads in the drivetrain components so measuring and calculating these loads can improve confidence in drivetrain design. This paper studies the Gearbox Reliability Collaborative 750kW wind turbine gearbox response during transient events using a combined experimental and modeling approach. The transient events include emergency shut-downs and start-ups measured during a field testing period in 2009. The drivetrain model is established in the multibody simulation tool Simpack. A detailed study of modeling fidelity required for accurate load prediction is performed and results are compared against measured loads. A high fidelity model that includes shaft and housing flexibility and accurate bearing stiffnesses is important for the higher-speed stage bearing loads. Each of the transient events has different modeling requirements.

17 WIND ENERGY↗
DOE OSTI2017

Superbubbles in the multiphase ISM and the loading of galactic winds

We use numerical simulations to analyze the evolution and properties of superbubbles (SBs), driven by multiple supernovae (SNe), that propagate into the two-phase (warm/cold), cloudy interstellar medium (ISM). We consider a range of mean background densities n{sub avg}=0.1--10 cm{sup −3} and intervals between SNe Δt{sub SN}=0.01--1 Myr, and follow each SB until the radius reaches ∼(1--2)H, where H is the characteristic ISM disk thickness. Except for embedded dense clouds, each SB is hot until a time t{sub sf,m} when the shocked warm gas at the outer front cools and forms an overdense shell. Subsequently, diffuse gas in the SB interior remains at T{sub h}∼10{sup 6}--10{sup 7} K, with an expansion velocity v{sub h}∼10{sup 2}--10{sup 3} km s{sup −1} (both highest for low Δt{sub SN}). At late times, the warm shell gas velocities are several tens to ∼100 km s{sup −1}. While shell velocities are too low to escape from a massive galaxy, they are high enough to remove substantial mass from dwarfs. Dense clouds are also accelerated, reaching a few to tens of km s{sup −1}. We measure the mass in hot gas per SN, M-hat {sub h}, and the total radial momentum of the bubble per SN, p-hat {sub b}. After t{sub sf,m}, M-hat {sub h}∼10--100 M{sub ⊙} (highest for low n{sub avg}), while p-hat {sub b}∼0.7--3×10{sup 5} M{sub ⊙} km s{sup −1} (highest for high Δt{sub SN}). If galactic winds in massive galaxies are loaded by the hot gas in SBs, we conclude that the mass-loss rates would generally be lower than star formation rates. Only if the SN cadence is much higher than usual in galactic disks, as may occur for nuclear starbursts, can SBs breakout while hot and expel up to 10 times the mass locked up in stars. The momentum injection values, p-hat {sub b}, are consistent with requirements to control star formation rates within galaxies at observed levels.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS2011

Reconstruction of Ares I-X Integrated Vehicle Rollout Loads

The measurements taken during the Ares I-X test flight provided a unique opportunity to assess the accuracy of the models and methods used to analyze the loads and accelerations present in the planned Ares I vehicle. During the rollout of the integrated vehicle from the Vehicle Assembly Building (VAB) to the launch pad, the vehicle and its supporting structure are subjected to wind loads and the vibrations produced by the crawler-transporter (CT) that is carrying it. While the loads induced on the vehicle during this period are generally low relative to those experienced in flight, the rollout is a period of operation of primary interest to those designing both the ground support equipment and the interfaces between the launch vehicle and its supporting structure. In this paper, the methods used for reconstructing the loads during the rollout phase are described. The results generated are compared to measured values, leading to insight into the accuracy of the Ares I assessment techniques.

Chamberlain, Matthew K.↗
NASA NTRS2011

Reconstruction of Ares I-X Integrated Vehicle Rollout Loads

The measurements taken during the Ares I-X test flight provided a unique opportunity to assess the accuracy of the models and methods used to analyze the loads and accelerations present in the planned Ares I vehicle. During the rollout of the integrated vehicle from the Vehicle Assembly Building (VAB) to the launch pad, the vehicle and its supporting structure are subjected to wind loads and the vibrations produced by the crawler-transporter (CT) that is carrying it. While the loads induced on the vehicle during this period are generally low relative to those experienced in flight, the rollout is a period of operation of primary interest to those designing both the ground support equipment and the interfaces between the launch vehicle and its supporting structure. In this paper, the methods used for reconstructing the loads during the rollout phase are described. The results generated are compared to measured values, leading to insight into the accuracy of the Ares I assessment techniques.

Chamberlain, Matthew K.↗
DOE OSTI2023

PVade (PV Aerodynamic Design Engineering) [SWR-23-49]

PV Aerodynamic Design Engineering (PVade) is an open-source fluid-structure interaction (FSI) solver which can accurately simulate wind loads and aerodynamic stability in solar-tracking PV arrays. PVade’s pressure profiles and inertial load time series can be used as inputs into mechanical module models to study degradation mechanisms including cracking of cells, weathering of cracked cells, and glass breakage. This software enables PV plant owners to predict optimal high-wind stow strategies under a variety of weather and site conditions.

Young, Ethan↗
NASA NTRS2000

Contributions of the NASA Langley Transonic Dynamics Tunnel to Launch Vehicle and Spacecraft Development

The NASA Langley Transonic Dynamics Tunnel (TDT) has provided wind-tunnel experimental validation and research data for numerous launch vehicles and spacecraft throughout its forty year history. Most of these tests have dealt with some aspect of aeroelastic or unsteady-response testing, which is the primary purpose of the TDT facility. However, some space-related test programs that have not involved aeroelasticity have used the TDT to take advantage of specific characteristics of the wind-tunnel facility. In general. the heavy gas test medium, variable pressure, relatively high Reynolds number and large size of the TDT test section have made it the preferred facility for these tests. The space-related tests conducted in the TDT have been divided into five categories. These categories are ground wind loads, launch vehicle dynamics, atmospheric flight of space vehicles, atmospheric reentry. and planetary-probe testing. All known TDT tests of launch vehicles and spacecraft are discussed in this report. An attempt has been made to succinctly summarize each wind-tunnel test, or in the case of multiple. related tests, each wind-tunnel program. Most summaries include model program discussion, description of the physical wind-tunnel model, and some typical or significant test results. When available, references are presented to assist the reader in further pursuing information on the tests.

Cole, Stanley R.↗
DOE OSTI2012

Comparison of Wind Power and Load Forecasting Error Distributions: Preprint

The introduction of large amounts of variable and uncertain power sources, such as wind power, into the electricity grid presents a number of challenges for system operations. One issue involves the uncertainty associated with scheduling power that wind will supply in future timeframes. However, this is not an entirely new challenge; load is also variable and uncertain, and is strongly influencedby weather patterns. In this work we make a comparison between the day-ahead forecasting errors encountered in wind power forecasting and load forecasting. The study examines the distribution of errors from operational forecasting systems in two different Independent System Operator (ISO) regions for both wind power and load forecasts at the day-ahead timeframe. The day-ahead timescale iscritical in power system operations because it serves the unit commitment function for slow-starting conventional generators.

17 WIND ENERGY↗
DOE OSTI2022

ARPA-E PERFORM datasets

Time-coincident load, wind, and solar data including actual and probabilistic forecast datasets at 5-min resolution for ERCOT, MISO, NYISO, and SPP. Wind and solar profiles are supplied for existing sites as well as planned sites based on interconnection queue projects as of 2021. For ERCOT actuals are provided for 2017 and 2018 and forecasts for 2018, and for the remaining ISOs actuals are provided for 2018 and 2019 and forecasts for 2019. There datasets were produced by NREL as part of the ARPA-E PERFORM project, an ARPA-E funded program that aim to use time-coincident power and load seeks to develop innovative management systems that represent the relative delivery risk of each asset and balance the collective risk of all assets across the grid. For more information on the datasets and methods used to generate them see https://github.com/PERFORM-Forecasts/documentation.

5-min data↗
DOE OSTI2019

Introducing Uncertainty Components in Locational Marginal Prices for Pricing Wind Power and Load Uncertainties

With substantially increasing penetration levels of wind power, electric power system flexibility is needed to address the variability and uncertainty of wind power output. Thus, it has become an urgent issue to obtain an optimal trade-off between economics and reliability, and to price system uncertainties. This paper proposes a new electricity market-clearing mechanism based on locational marginal prices (LMPs) for pricing uncertain generation and load. The uncertainty contained locational marginal price (U-LMP) is derived from a distributionally robust chance-constrained optimal power flow (DRCC-OPF) model in which only the first-order and second-order moments of the uncertain sources' probability distribution are needed. Compared with traditional LMPs, the proposed U-LMP formulation includes two new uncertainty components: transmission line overload uncertainty price and generation violation uncertainty price. These LMP uncertainty components are the price signals reflecting the system costs as a result of wind generation and demand uncertainty at different locations. Finally, using parametric case studies, the relationship among uncertainty levels, system generation cost, and LMP uncertainty components are established. Case studies performed on the PJM 5-bus and IEEE 118-bus systems verify the proposed U-LMP method.

24 POWER TRANSMISSION AND DISTRIBUTION↗
NASA NTRS2007

Stellar Ablation of Planetary Atmospheres

We review observations and theories of the solar ablation of planetary atmospheres, focusing on the terrestrial case where a large magnetosphere holds off the solar wind, so that there is little direct atmospheric impact, but also couples the solar wind electromagnetically to the auroral zones. We consider the photothermal escape flows known as the polar wind or refilling flows, the enhanced mass flux escape flows that result from localized solar wind energy dissipation in the auroral zones, and the resultant enhanced neutral atom escape flows. We term these latter two escape flows the "auroral wind." We review observations and theories of the heating and acceleration of auroral winds, including energy inputs from precipitating particles, electromagnetic energy flux at magnetohydrodynamic and plasma wave frequencies, and acceleration by parallel electric fields and by convection pickup processes also known as "centrifugal acceleration." We consider also the global circulation of ionospheric plasmas within the magnetosphere, their participation in magnetospheric disturbances as absorbers of momentum and energy, and their ultimate loss from the magnetosphere into the downstream solar wind, loading reconnection processes that occur at high altitudes near the magnetospheric boundaries. We consider the role of planetary magnetization and the accumulating evidence of stellar ablation of extrasolar planetary atmospheres. Finally, we suggest and discuss future needs for both the theory and observation of the planetary ionospheres and their role in solar wind interactions, to achieve the generality required for a predictive science of the coupling of stellar and planetary atmospheres over the full range of possible conditions.

Moore, Thomas E.↗
DOE OSTI2018

Assessment of Wind Turbine Component Loads Under Yaw-Offset Conditions

Renewed interest in yaw control for wind turbine and power plants for wake redirection and load mitigation demands a clear understanding of the effects of running with skewed inflow. In this paper, we investigate the physics of yawed operations, building up the complexity from a simplified analytical treatment to more complex aeroelastic simulations. Results in terms of damage equivalent loads (DELs) and extreme loads under operating, misaligned conditions are compared to data collected from an instrumented, utility-scale wind turbine. The analysis shows that multiple factors are responsible for the DELs of the various components, and that airfoil aerodynamics, elastic characteristics of the rotor, and turbulence intensities are the primary drivers. Both fatigue and extreme loads are observed to have relatively complex trends with yaw offsets, which can change depending on the wind-speed regime. As a result, good agreement is found between predicted and measured trends for both fatigue and ultimate loads.

17 WIND ENERGY↗
DOE OSTI2012

DIRECT NUMERICAL SIMULATION OF RADIATION PRESSURE-DRIVEN TURBULENCE AND WINDS IN STAR CLUSTERS AND GALACTIC DISKS

The pressure exerted by the radiation of young stars may be an important feedback mechanism that drives turbulence and winds in forming star clusters and the disks of starburst galaxies. However, there is great uncertainty in how efficiently radiation couples to matter in these high optical depth environments. In particular, it is unclear what levels of turbulence the radiation can produce, and whether the infrared radiation trapped by the dust opacity can give rise to heavily mass-loaded winds. In this paper, we report a series of two-dimensional flux-limited diffusion radiation-hydrodynamics calculations performed with the code ORION in which we drive strong radiation fluxes through columns of dusty matter confined by gravity in order to answer these questions. We consider both systems where the radiation flux is sub-Eddington throughout the gas column, and those where it is super-Eddington at the midplane but sub-Eddington in the atmosphere. In the latter, we find that the radiation-matter interaction gives rise to radiation-driven Rayleigh-Taylor instability, which drives supersonic turbulence at a level sufficient to fully explain the turbulence seen in Galactic protocluster gas clouds, and to make a non-trivial contribution to the turbulence observed in starburst galaxy disks. However, the instability also produces a channel structure in which the radiation-matter interaction is reduced compared to time-steady analytic models because the radiation field is not fully trapped. For astrophysical parameters relevant to forming star clusters and starburst galaxies, we find that this effect reduces the net momentum deposition rate in the dusty gas by a factor of {approx}2-6 compared to simple analytic estimates, and that in steady state the Eddington ratio reaches unity and there are no strong winds. We provide an approximation formula, appropriate for implementation in analytic models and non-radiative simulations, for the force exerted by the infrared radiation field in this regime.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2022

Achieving an 80% carbon-free electricity system in China by 2035

Dramatic reductions in solar, wind, and battery storage costs create new opportunities to reduce emissions and costs in China’s electricity sector, beyond current policy goals. This study examines the cost, reliability, emissions, public health, and employment implications of increasing the share of non-fossil fuel (“carbon free”) electricity generation in China to 80% by 2035. The analysis uses state-of-the-art modeling with high resolution load, wind, and solar inputs. The study finds that achieving an 80% carbon free electricity system in China by 2035 could reduce wholesale electricity costs, relative to a current policy baseline, while maintaining high levels of reliability, reducing deaths from air pollution, and increasing employment. In our 80% scenario, wind and solar generation capacity reach 3 TW and battery storage capacity reaches 0.4 TW by 2035, implying a rapid scale up in these resources that will require changes in policy targets, markets and regulation, and land use policies.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
NASA NTRS2015

Assimilation of Wind Profiles from Multiple Doppler Radar Wind Profilers for Space Launch Vehicle Applications

Space launch vehicles utilize atmospheric winds in design of the vehicle and during day-of-launch (DOL) operations to assess affects of wind loading on the vehicle and to optimize vehicle performance during ascent. The launch ranges at NASA's Kennedy Space Center co-located with the United States Air Force's (USAF) Eastern Range (ER) at Cape Canaveral Air Force Station and USAF's Western Range (WR) at Vandenberg Air Force Base have extensive networks of in-situ and remote sensing instrumentation to measure atmospheric winds. Each instrument's technique to measure winds has advantages and disadvantages in regards to use for vehicle engineering assessments. Balloons measure wind at all altitudes necessary for vehicle assessments, but two primary disadvantages exist when applying balloon output on DOL. First, balloons need approximately one hour to reach required altitude. For vehicle assessments this occurs at 60 kft (18.3 km). Second, balloons are steered by atmospheric winds down range of the launch site that could significantly differ from those winds along the vehicle ascent trajectory. Figure 1 illustrates the spatial separation of balloon measurements from the surface up to approximately 55 kft (16.8 km) during the Space Shuttle launch on 10 December 2006. The balloon issues are mitigated by use of vertically pointing Doppler Radar Wind Profilers (DRWPs). However, multiple DRWP instruments are required to provide wind data up to 60 kft (18.3 km) for vehicle trajectory assessments. The various DRWP systems have different operating configurations resulting in different temporal and spatial sampling intervals. Therefore, software was developed to combine data from both DRWP-generated profiles into a single profile for use in vehicle trajectory analyses. Details on how data from various wind measurement systems are combined and sample output will be presented in the following sections.

Decker, Ryan K.↗
NASA NTRS1964

Trends in high-speed atmospheric flight

Some of the current problems and future trends for three types of flight within the Earth's atmosphere are considered. The three areas examined are atmosphere entry at very high speeds, atmosphere exit of launch vehicles, and sustained cruise within the atmosphere. The high-speed entry problems described are those encountered by vehicles returning to Earth after a manned mission to Mars. Such vehicles will experience atmosphere entry speeds up to 50,000 and perhaps as high as 70,000 feet per second. For these vehicles to execute a successful entry, accurate guidance at Earth approach must be provided and very precise control during the flight within the atmosphere will be a necessity. At the high entry speeds radiative heating-is greater than convective and thus it tends to exert a dominant influence on entry-vehicle configuration. The study and development of relatively slender vehicles is indicated in order to minimize the large radiative heating loads and associated heat-shield weights. Manned interplanetary missions in the future may also involve a need for very large launch vehicles. These large vehicles will have aerodynamic problems which differ somewhat from current problems. For example, drag losses decrease with increasing size and large vehicles may thus be of lower fineness ratio than present-day vehicles. With lower fineness ratio some of the difficult current problems produced by ground-wind loads and by buffet of hammerhead payload mountings will be avoided. In the case of high-speed cruise within the Earth's atmosphere, the use of hydrogen-fueled, airbreathing engines may permit attractive payload capabilities for long-range high-speed transports. For such vehicles aerodynamic problems arise because of the numerous constraints placed upon their flight paths as well as from the large volumes required for the hydrogen fuel. From payload considerations alone, attractive cruise speeds for such vehicles currently appear to be about twice that of the conventionally fueled supersonic transports now being intensively studied.

Atmospheric entry↗