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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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All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Quantifying point defects in Cu 2 ZnSn(S,Se) 4 thin films using resonant x-ray diffraction

Cu 2ZnSn(S,Se)4 is an interesting, earth abundant photovoltaic material, but has suffered from low open circuit voltage. To better understand the film structure, we have measured resonant x-ray diffraction across the Cu and Zn K-edges for the device quality thin films of Cu 2ZnSnS4 (8.6% efficiency) and Cu 2ZnSn(S,Se)4 (3.5% efficiency). This approach allows for the confirmation of the underlying kesterite structure and quantification of the concentration of point defects and vacancies on the Cu, Zn, and Sn sublattices. Rietveld refinement of powder diffraction data collected at multiple energies is used to determine that there exists a high level of Cu Zn and Zn Cu defects on the 2c and 2d Wyckoff positions. We observe a significantly lower concentration of Zn Sn defects and Cu or Zn vacancies.

14 SOLAR ENERGY↗
DOE OSTI2019

Polynomial-product states: A symmetry-projection-based factorization of the full coupled cluster wavefunction in terms of polynomials of double excitations

Our goal is to remedy the failure of symmetry-adapted coupled-cluster theory in the presence of strong correlation. Previous work along these lines has taken us from a diagram-level analysis of the coupled-cluster equations to an understanding of the collective modes which can occur in various channels of the coupled-cluster equations to the exploration of non-exponential wavefunctions in efforts to combine coupled-cluster theory with symmetry projection. In this manuscript, we extend these efforts by introducing a new, polynomial product wavefunction ansatz that incorporates information from symmetry projection into standard coupled-cluster theory in a way that attempts to mitigate the effects of the lack of size extensivity and size consistency characteristic of symmetry-projected methods. Finally, we describe the new approach in detail within the context of our previous efforts, explore some illustrative calculations, and consider one route for reducing the computational cost of the new method.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Assessment of personal airborne exposures and surface contamination from x-ray vaporization of beryllium targets at the National Ignition Facility

Here, this article presents air and surface sampling data collected over the first two years since beryllium was introduced as a target material at the National Ignition Facility. Over this time, 101 experiments with beryllium-containing targets were executed. The data provides an assessment of current conditions in the facility and a baseline for future impacts as new, reduced regulatory limits for beryllium are being proposed by both the Occupational Safety and Health Administration and Department of Energy. This study also investigates how beryllium deposits onto exposed surfaces as a result of x-ray vaporization and the effectiveness of simple decontamination measures in reducing the amount of removable beryllium from a surface. Based on 1,961 surface wipe samples collected from entrant components (equipment directly exposed to target debris) and their surrounding work areas during routine reconfiguration activities, only one result was above the beryllium release limit of 0.2 µg/100 cm 2 and 27 results were above the analytical reporting limit of 0.01 µg/100 cm 2 , for a beryllium detection rate of 1.4%. Surface wipe samples collected from the internal walls of the NIF target chamber, however, showed higher levels of beryllium, with beryllium detected on 73% and 87% of the samples during the first and second target chamber entries (performed annually), respectively, with 23% of the samples above the beryllium release limit during the second target chamber entry. The analysis of a target chamber wall panel exposed during the first 30 beryllium-containing experiments (cumulatively) indicated that 87% of the beryllium contamination remains fixed onto the surface after wet wiping the surface and 92% of the non-fixed contamination was removed by decontaminating the surface using a dry wipe followed by a wet wipe. Personal airborne exposures assessed during access to entrant components and during target chamber entry indicated that airborne beryllium was not present in workers' breathing zones. Finally, all the data thus far have shown that beryllium has been effectively managed to prevent exposures to workers during routine and non-routine work.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Application of end-of-shift respirable crystalline silica monitoring to construction

A pilot project was conducted to determine the effect of common construction dusts as interferences in a new portable end-of-shift (EoS), direct-on-filter (DoF) sampling and analysis method for respirable crystalline silica (RCS), in this case, quartz. Construction dusts were prepared from plaster, drywall, cement and brick by grinding, aerosolizing, and collecting respirable dust with high flow rate cyclones. Filters were loaded with different levels of commercial α-quartz powder Min-u-Sil 5, and different levels of interfering dusts, singly and in combination. Samples were analyzed by Fourier Transform Infrared Spectroscopy (FTIR). Good correlations were found between nominal quartz loading (0 µg, 25 µg, 50 µg, and 100 µg) adjusted for quartz in the interfering dust and FTIR absorbance alone and in the presence of all interfering dusts. The slopes of the correlations were similar whether the loading was quartz without interference, or with plaster, drywall, and cement dusts, regardless of quantity. The results show that (a) plaster and drywall dusts do not interfere substantially; (b) cement does not interfere, but a change in the intercept suggests an effect on the background absorbance of the filter; and (c) in addition to having a substantial quartz content, brick dust contains an additional material, probably a silicate mineral, which interferes with the quartz peak. Thus, the presence of cement leads to lower quartz values and brick leads to higher values, but overall, 83% of the quartz contents predicted from the calibration data agreed within 50% of the adjusted nominal loadings within the range 20–110 µg. This result is encouraging given the high levels of interfering dusts. Nine samples loaded with smaller amounts of all four dusts together gave results within 25% of the adjusted nominal loadings. A single mixture addition of the dusts to the filter gave tighter variance in results than sequential additions. Unexpectedly, the two Certified Reference Materials (CRMs) 1878a and 1878b, gave different results when used to calibrate XRD analysis of Min-u-Sil 5.

42 ENGINEERING↗
DOE OSTI2022

LiDAR Measurements of Wind Shear Exponents and Turbulence Intensity Offshore the Northeast United States

This paper presents wind speed shear exponents and turbulence intensity measurements collected from LiDARs measuring wind speeds from 40m to 200m above sea-level and provides comparisons to industry design guidelines. The high-altitude wind speed data are unique and represent some of the first measurements made offshore in this part of the country, which is actively being developed for offshore wind. The data is used to support the New England Aqua Ventus I Floating Offshore Wind Farm to be located 17km offshore the Northeast United States. Multiple LiDAR measurements were made using a DeepCLiDAR floating buoy and LiDARs located on a nearby island. Here, the measured wind speed shear exponents are compared against industry standard mesoscale model outputs and offshore design codes including the American Bureau of Shipping, American Petroleum Institute, and DNV-GL guides. Significant variation in the vertical wind speed profile occurs throughout the year which is not addressed in design standards. Additionally, turbulence intensity measurements made from the LiDAR, although not widely accepted in the scientific community, are presented and compared against industry guidelines.

42 ENGINEERING↗
DOE OSTI2021

Effects of a nuclear disturbed environment on a quantum free space optical link

This manuscript investigates the potential effect of a nuclear-disturbed atmospheric environment on the signal attenuation of a ground/satellite transmitter/receiver system for both classical optical and quantum communications applications. Attenuation of a signal transmitted through the rising nuclear cloud and the subsequently transported debris is modeled climatologically for surface-level detonations of 10 kt, 100 kt, and 1 Mt. Attenuation statistics were collected as a function of time after detonation. These loss terms were compared to normal loss sources such as clouds, smoke from fires, and clear sky operation. Finally, the loss was related to the degradation of transmitted entanglement derived from Bayesian mean estimation.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2025

Snow Depth Datasets for Snodgrass Catchment, Colorado, Water Year 2022-2023

This data package presents snow depths data from distributed temperature probes at 18 locations near Snodgrass catchment, Colorado. These data show that snow melt-out dates are approximately one or two weeks later under evergreen forests compared to other vegetation types even at the same elevation. These data were collected to understand how snowmelt heterogeneity impacts headwater hydrology, including streamflow and groundwater levels. They were also used to compare with process-based model simulations of snow depth to evaluate whether the model accurately represents snowmelt dynamics and their effects on headwater hydrology. Snow_DTPs_locations.csv includes all probes locations and their associated elevation and vegetation types. Snow_Depth_Snodgrass_WY2022_2023.csv includes processed snow depths datasets for Water Year (WY) 2022 and 2023. This dataset also includes a file-level metadata (flmd.csv) file that lists each file contained in the dataset with associated metadata and a data dictionary (dd.csv) file that contains column/row headers used throughout the files along with a definition, units, and data type. Several probes have recordings for WY 2021.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2011

Closure Report for Corrective Action Unit 566: EMAD Compound, Nevada National Security Site, Nevada with ROTCs 1-2, Revision 0

This Closure Report (CR) presents information supporting the closure of Corrective Action Unit (CAU) 566: EMAD Compound, Nevada National Security Site, Nevada. Corrective Action Unit 566 comprises Corrective Action Site (CAS) 25-99-20, EMAD Compound, located within Area 25 of the Nevada National Security Site. The purpose of this CR is to provide documentation supporting the completed corrective actions and provide data confirming that the closure objectives for CAU 566 were met. To achieve this, the following actions were performed: • Review the current site conditions, including the concentration and extent of contamination. • Implement any corrective actions necessary to protect human health and the environment. • Properly dispose of corrective action and investigation wastes. • Document Notice of Completion and closure of CAU 566 issued by the Nevada Division of Environmental Protection. From October 2010 through May 2011, closure activities were performed as set forth in the Streamlined Approach for Environmental Restoration Plan for CAU 566: EMAD Compound, Nevada National Security Site, Nevada. The purposes of the activities as defined during the data quality objectives process were as follows: • Determine whether contaminants of concern (COCs) are present. • If COCs are present, determine their nature and extent, implement appropriate corrective actions, and properly dispose of wastes. Analytes detected during the closure activities were evaluated against final action levels (FALs) to determine COCs for CAU 566. Assessment of the data from collected soil samples, and from radiological and visual surveys of the site, indicates the FALs were exceeded for polychlorinated biphenyls (PCBs), semivolatile organic compounds (SVOCs), and radioactivity. Corrective actions were implemented to remove the following: • Radiologically contaminated soil assumed greater than FAL at two locations • Radiologically contaminated soil assumed greater than FAL with lead shot • PCB-contaminated soil • Radiologically contaminated filters and equipment • Fuels, lubricants, engine coolants, and oils • Lead debris • Electrical and lighting components assumed to be potential source materials, including - fluorescent light bulbs - mercury switches (thermostats) - circuit boards - PCB-containing ballasts Closure of CAU 566 was achieved through a combination of removal activities and closure in place. Corrective actions to remove COCs, and known and assumed potential source materials, were implemented as was practical. The PCBs remaining at the site are bounded laterally, but not vertically, within CAS 25-99-20 based upon step-out sampling; the sources (e.g., PCB transformer oils, diesel fuel from locomotive reservoirs) have been removed; the practice of the application of PCB-containing oils for soil stabilization has ceased; and the COCs are not readily mobile in the environment. Closure in place is necessary, and future land use of the site will be restricted from intrusive activities. This will effectively eliminate inadvertent contact by humans with the contaminated media. The DOE, National Nuclear Security Administration Nevada Site Office, provides the following recommendations: • No further corrective action is required at CAS 25-99-20. • Closure in place of CAS 25-99-20. • A use restriction is required at CAU 566. • A Notice of Completion to the DOE, National Nuclear Security Administration Nevada Site Office, is requested from the Nevada Division of Environmental Protection for closure of CAU 566. • Corrective Action Unit 566 should be moved from Appendix III to Appendix IV of the Federal Facility Agreement and Consent Order.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2013

DOE Robotic and Remote Systems Assistance to the Government of Japan

At the request of the Government of Japan, DOE did a complex wide survey of available remotely operated and robotic systems to assist in the initial assessment of the damage to the Fukushima Daiichi reactors following an earthquake and subsequent tsunami. As a result several radiation hardened cameras and a Talon robot were identified as systems that could immediately assist in the effort and were subsequently sent to Japan. These systems were transferred to the Government of Japan and used to map radiation levels surrounding the damaged facilities. This report describes the equipment, its use, data collected, and lessons learned from the experience.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2013

Minimizing System Noise Effects For Extreme-Scale Scientific Simulation Through Function Delegation

The primary goal of the Minimizing System Noise Effects For Extreme-Scale Scientific Simulation through Function Delegation project is to eliminate or at best strongly minimize the impact of the noise introduced by the operating system, during large scale parallel applications runs. Collective communication operations are a basic building block for parallel programing models and scientific applications. These operations often dominate execution time of applications and tend to limit their scalability. In order to address this challenge, we evaluated different strategies to adapt the collective communications underlying topologies to the hardware architecture in order to provide increased levels of performance to the parallel applications.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2013

Summary Report of Ecological Risk Assessment for the Operation of the Explosives Waste Treatment Facility at Site 300 of the Lawrence Livermore National Laboratory.

An ecological risk assessment is required as part of the Resource Recovery and Conservation Act (RCRA) permit renewal process for Miscellaneous Units subject to 22 CCR 66270.23. This risk assessment is prepared in support of the RCRA permit renewal for the Explosives Waste Treatment Facility (EWTF) at Site 300 of the Lawrence Livermore National Laboratory (LLNL). LLNL collected soil samples and used the resulting data to produce a scoping-level ecological risk assessment pursuant to the Department of Toxic Substances Control, Guidance for Ecological Risk Assessment at Hazardous Waste Sites and Permitted Facilities, Part A: Overview, July 4, 1996. The scoping-level ecological risk assessment provides a framework to determine the potential interaction between ecological receptors and chemicals of concern from hazardous waste treatment operations in the area of EWTF. A scoping-level ecological risk assessment includes the step of conducting soil sampling in the area of the treatment units. The Sampling Plan in Support of the Human Health and Ecological Risk Assessment for the Operation of the Explosives Waste Treatment Facility at Site 300 of the Lawrence Livermore National Laboratory, (Terusaki, 2007), outlines the EWTF project-specific soil sampling requirements. Soil samples were obtained and analyzed for constituents from four chemical groups: furans, explosives, semi-volatiles and metals. Analytical results showed that furans, explosives and semi-volatiles were not detected; therefore, no further analysis was conducted. The soil samples did show the presence of metals. Soil samples analyzed for metals were compared to site-wide background levels, which had been developed for site -wide cleanup activities pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). Total metal concentrations from 28 discrete soil samples obtained in the EWTF area were all below CERCLA-developed background levels. Therefore, following DTSC 1996 guidance, the EWTF hazardous waste treatment units exit the ecological risk evaluation process upon completion of the requirements of a scoping-level assessment report. This summary report documents that the requirements of a scoping-level assessment have been met.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Searches for New Symmetries in pp Collisions with the Razor Kinematic Variables at $\mathbf{\sqrt{s}} =$ 7 TeV

The construction and LHC phenomenology of the razor variables M R , an event-by-event indicator of the heavy particle mass scale, and R, a dimensionless variable related to the transverse momentum imbalance of events and missing transverse energy, are presented. The variables are used in the analysis of the first proton-proton collisions dataset at CMS (35 pb -1 ) in a search for superpartners of the quarks and gluons, targeting indirect hints of dark matter candidates in the context of supersymmetric theoretical frameworks. The analysis produced the highest sensitivity results for SUSY to date and extended the LHC reach far beyond the previous Tevatron results. A generalized inclusive search is subsequently presented for new heavy particle pairs produced in √s = 7 TeV proton-proton collisions at the LHC using 4.7±0.1 fb -1 of integrated luminosity from the second LHC run of 2011. The selected events are analyzed in the 2D razor-space of MR and R and the analysis is performed in 12 tiers of all-hadronic, single and double leptons final states in the presence and absence of b-quarks, probing the third generation sector using the event heavy- flavor content. The search is sensitive to generic supersymmetry models with minimal assumptions about the superpartner decay chains. No excess is observed in the number or shape of event yields relative to Standard Model predictions. Exclusion limits are derived in the CMSSM framework with gluino masses up to 800 GeV and squark masses up to 1.35 TeV excluded at 95% confidence level, depending on the model parameters. The results are also interpreted for a collection of simplified models, in which gluinos are excluded with masses as large as 1.1 TeV, for small neutralino masses, and the first-two generation squarks, stops and sbottoms are excluded for masses up to about 800, 425 and 400 GeV, respectively.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

Puget Sound Dissolved Oxygen Modeling Study: Development of an Intermediate Scale Water Quality Model

The Salish Sea, including Puget Sound, is a large estuarine system bounded by over seven thousand miles of complex shorelines, consists of several subbasins and many large inlets with distinct properties of their own. Pacific Ocean water enters Puget Sound through the Strait of Juan de Fuca at depth over the Admiralty Inlet sill. Ocean water mixed with freshwater discharges from runoff, rivers, and wastewater outfalls exits Puget Sound through the brackish surface outflow layer. Nutrient pollution is considered one of the largest threats to Puget Sound. There is considerable interest in understanding the effect of nutrient loads on the water quality and ecological health of Puget Sound in particular and the Salish Sea as a whole. The Washington State Department of Ecology (Ecology) contracted with Pacific Northwest National Laboratory (PNNL) to develop a coupled hydrodynamic and water quality model. The water quality model simulates algae growth, dissolved oxygen, (DO) and nutrient dynamics in Puget Sound to inform potential Puget Sound-wide nutrient management strategies. Specifically, the project is expected to help determine 1) if current and potential future nitrogen loadings from point and non-point sources are significantly impairing water quality at a large scale and 2) what level of nutrient reductions are necessary to reduce or control human impacts to DO levels in the sensitive areas. The project did not include any additional data collection but instead relied on currently available information. This report describes model development effort conducted during the period 2009 to 2012 under a U.S. Environmental Protection Agency (EPA) cooperative agreement with PNNL, Ecology, and the University of Washington awarded under the National Estuary Program

algae↗
DOE OSTI2012

Offshore Resource Assessment and Design Conditions: A Data Requirements and Gaps Analysis for Offshore Renewable Energy Systems

The offshore renewable energy industry requires accurate meteorological and oceanographic (“metocean”) data for evaluating the energy potential, economic viability, and engineering requirements of offshore renewable energy projects. It is generally recognized that currently available metocean data, instrumentation, and models are not adequate to meet all of the stakeholder needs on a national scale. Conducting wind and wave resource assessments and establishing load design conditions requires both interagency collaboration as well as valuable input from experts in industry and academia. Under the Department of Energy and Department of Interior Memorandum of Understanding, the Resource Assessment and Design Condition initiative supports collaborative national efforts by adding to core atmospheric and marine science knowledge relevant to offshore energy development. Such efforts include a more thorough understanding and data collection of key metocean phenomena such as wind velocity and shear; low-level jets; ocean, tidal, and current velocities; wave characteristics; geotechnical data relating to surface and subsurface characteristics; seasonal and diurnal variations; and the interaction among these conditions. Figure 1 presents a graphical representation of some metocean phenomena that can impact offshore energy systems. This document outlines the metocean observations currently available; those that are not available; and those that require additional temporal-spatial coverage, resolution, or processing for offshore energy in an effort to gather agreed-upon, needed observations.

16 TIDAL AND WAVE POWER↗
DOE OSTI2017

Graphene Charge Transfer, Spectroscopy, and Photochemical Reactions

This project focused on the special electronic and optical properties of graphene and adsorbed molecular species. Graphene makes an excellent substrate for current collection in nanostructured photovoltaic designs. Graphene is almost transparent, and can be used as a solar cell window. It also has no surface states, and thus current is efficiently transported over long distances. Progress in graphene synthesis indicates that there will soon be practical methods for making large pieces of graphene for devices. We now need to understand exactly what happens to both ground state and electronically excited molecules and Qdots near graphene, if we are going to use them to absorb light in a nano-structured photovoltaic device using graphene to collect photocurrent. We also need to understand how to shift the graphene Fermi level, to optimize the kinetics of electron transfer to graphene. And we need to learn how to convert local graphene areas to semiconductor structure, to make useful spatially patterned graphenes. In this final report, we describe how we addressed these goals. We explored the question of possible Surface Enhanced Raman spectroscopy from molecular Charge Transfer onto Graphene substrates. We observed strong hole doping of graphene by adsorbed halogens as indicated by the shift of the graphene G Raman band. In the case of iodine adsorption, we also observed the anionic species made by hole doping. At low frequency in the Raman spectrum, we saw quite intense lines from I 3 - and I 5 - , suggesting possible SERS. We reported on Fresnel calculations on this thin film system, which did not show any net electromagnetic field enhancement.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2018

Diffusion of Innovations: Interplay of Social, Economic, Technological, and Policy Drivers in the Solar Industry. Summary of UT Austin Student Capstone Research Projects

The University of Texas at Austin’s Policy Research Project (PRP), a nine-month (two semesters) capstone, is a keystone of the core curriculum at the LBJ School of Public Affairs. In PRPs, small groups of students, under the mentorship of a faculty director, take on real-world problems that require special knowledge and skill sets. PRPs expose students to challenges in formulating and executing research, and in communicating academic research and related complex data to broader stakeholder communities and decision makers. The PRP structure is an innovative and effective approach for integrating research within the teaching and training of graduate students who are preparing themselves to address important real-world problems at the intersection of society, economics, technology, and policy. The project summaries below describe seven papers developed during September 2017 – May 2018 as part of a PRP on “Diffusion of Innovations: Interplay of Social, Economic, Technological, and Policy Drivers in the Solar Industry.” Twenty graduate students, drawn from the LBJ School’s Masters in Public Affairs and Masters in Global Policy Studies programs and the Jackson School Geoscience’s Energy and Earth Resources program, participated in this PRP. Dr. Varun Rai, Associate Professor and Associate Dean for Research at the LBJ School, directed the PRP, with support from his research team including: Dr. Ariane Beck, Dr. Ashok Sekar, D. Cale Reeves, and Erik Funkhouser. Clients for the project included the U.S. Department of Energy (Casey Canfield), Lawrence Berkeley National Laboratory (Ben Hoen, Galen Barbose Joachim Seel, Naïm Darghouth, Ryan Wiser), and National Renewable Energy Laboratory (Benjamin Sigrin, Eric O’Shaughnessy). The seven projects separately addressed one of the following topics: (1) low- and middle-income PV adoption, (2) modeling economic and information intervention design, (3) evaluation of DOE’s Solar in Your Community Challenge, (4) property value impacts near large-scale solar facilities, (5) solar market maturity and evolution of business models, (6) social media data for predicting PV adoption, and (7) individual-level variation in adoption of innovations. Many of the papers relied on data collected and curated by Lawrence Berkeley National Laboratory, including data embedded within the annual Tracking the Sun and Utility-Scale Solar reports. Each of the seven teams in the PRP prepared a research paper. The PRP culminated with a full-day conference at UT Austin in May 2018 to present findings from the seven projects in this PRP to a broad audience of about 75 experts from academia, national labs, industry, and government from across the country.

14 SOLAR ENERGY↗
DOE OSTI2021

Large-Scale, GPU-Enhanced DFTB Approaches for Probing Multi-Component Alloys

The major goals of the project are to develop and apply GPU-enhanced density functional theory tight binding (DFTB) calculations for efficient simulations of structural materials of alloy systems. The figure below depicts the GPU algorithmic developments on the left that will be carried out, and the solid-state structures on the right are representative of the complex alloys that can be computed with the GPU-enhanced DFTB approach. The methodology and tools developed in this project encompass accurate intermolecular potentials and GPU enhancements to the density functional tight binding (DFTB) approach for high-throughput ab initio molecular dynamics calculations of multi-component alloys at elevated temperatures. While classical molecular dynamics can handle hundreds of thousands of atoms, it cannot provide a first-principles based description of large, multi-component alloys at the predictive quantum level. At the other extreme, conventional Kohn-Sham DFT methods can probe the true quantum nature of chemical systems; however, these methods cannot tackle the large sizes relevant to these multi-component systems. The DFTB-based ab initio molecular dynamics approach (coupled with our in-house GPU capabilities for enhanced speed) used in this project provides a viable approach for probing these large systems at a quantum level of detail that is significantly faster than current first-principle methods Collectively, the capabilities developed in this project directly respond to DOE HBCU-OMI, AOI 2-1 initiatives by (1) enabling accurate and efficient predictions and (2) bringing a fundamental understanding of structural interactions in these complex systems at elevated temperatures.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2025

Advanced Model Development for Large Eddy Simulation of Oxy-Combustion and Supercritical Carbon Dioxide Power Cycles

A joint experimental and numerical study is performed to observe the characteristics of a supercritical carbon dioxide turbulent mixing layer in the presence of strong nonlinearities in the thermodynamic and transport properties. A bespoke experimental setup is designed and employed for this purpose and provides insight into macroscopic mixing behavior. The mixing is experimentally observed using two techniques: shadowgraphy and spontaneous Raman scattering. Qualitative and quantitative intensity fields obtained via these techniques yield instantaneous and mean density data. Spanwise temperature data is also collected using analogue resistance temperature detectors. These measurements are used to quantify the level of mixed material within the field. The experimental data are supplemented by a companion high-fidelity numerical study. The numerical results are obtained through fully resolved, three-dimensional direct numerical simulation. The numerical dataset permits observation of the near-field mixing characteristics, which are difficult to measure experimentally due to the rapid dynamics and sharp thermophysical gradients in this area. Qualitative field visualizations are presented, followed by quantitative mixed material results and observations regarding thermodynamic property trends at select locations within the field. One-dimensional spectra of the turbulent kinetic energy and solenoidal dissipation are provided to observe the spectral characteristics of the flow. Reynolds stress anisotropy is analyzed graphically through anisotropy invariance maps (Lumley triangles). The mixing quantification, spectral data and anisotropy analysis of a flow at these thermodynamic conditions represent the main outcomes of the work.

20 FOSSIL-FUELED POWER PLANTS↗