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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 757 records · Page 42
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Development of Mixed-Salt Technology for CO 2 Capture from Coal Power Plants (Final Report)

SRI International (SRI), in collaboration with Stanford University, OLI Systems (OLI), Politecnico de Milano (PoliMi), and Aqueous Systems Aps (ASApS) performed a 45-month effort to develop a promising Mixed-Salt Process (MSP) for carbon dioxide capture. The MSP combines existing ammonia and potassium-carbonate technologies with improved absorption steps for rate enhancement and ammonia emission reduction and a novel selective regeneration process with a high-pressure CO 2 product to introduce a new and advanced transformational solvent-based technology. The striking advantages of the SRI MSP include: low heat of reaction, high loading of CO 2 , high-pressure regeneration of > 99% pure dry CO 2 , low sensitivity to impurities, low process cost, use of a non-degradable low-cost solvent with a very low carbon footprint for its production, low emissions, and reduced water use compared to the state-of-the-art ammonia-based and amine technologies. The overall objective of the project was to develop and test a solvent-based CO 2 capture technology that can capture CO 2 from existing or new pulverized coal (PC) power plants at low cost. Our specific goal was to test SRI’s newly developed MSP at the large bench-scale level to demonstrate that the process could capture CO 2 at high efficiency (> 90%) with very high CO 2 loading (> 10 wt.%), require less than 2 GJ/tonne for solvent regeneration, and produce a CO2 stream at high pressure with a purity > 95 vol.%. This 45-month MSP development program was designed to conduct (1) extensive test campaigns with different process flowsheet variants, and (2) detailed thermodynamic, kinetic, and process modeling. These tests and models were very important to identify any issues associated with the process in the early stages and then resolve them before moving into the next scale-up (> 1 MWe scale) testing. Such an approach reduces the risks associated with the process operability at large scales and provides capital and operating expenditure (CAPEX/OPEX) predictions with improved accuracies. Under the MSP development program at SRI, we performed an aggressive testing campaign with individual subsystems as well as integrated CO 2 capture and regeneration system to identify the best operating conditions. The project was carried out in two budget periods (BP1 & BP2).

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2018

Development and Rigorous Validation of Modules for Predicting Organic Aerosol CCN Activity from Molecular Properties

The indirect interaction of anthropogenic aerosols with clouds (aerosol indirect forcing) represents one of the main uncertainties in climate projections, and reducing this uncertainty requires improved understanding of the aerosol life cycle, including atmospheric aging and the ability to nucleate cloud droplets or crystals. A key parameter that links the chemical properties of aerosol to its nucleating properties, and ultimately to aerosol indirect forcing, is its hygroscopicity (ability to uptake water). One way to compare and systematize the ability of various chemical compounds or particle types to nucleate cloud drops is via the hygroscopicity parameter κ, which can be used directly in global models to simulate aerosol indirect forcing. In this project we further investigated the relationships between the chemical composition of organic aerosol particles, which are known to be important components of atmospheric particulate matter, and their ability to serve as cloud condensation nuclei (CCN). In particular, we isolated the role of viscosity on κ by applying methods similar to those we used previously in our DOE/ASR research. Our motivation for the focus on viscosity was through its link to particle phase state. Particle phase affects water uptake on timescales relevant to the laboratory and also likely relevant to atmospheric processes, with reduced apparent hygroscopicities for semisolid and solid particles, compared with liquid particles. Water uptake itself affects viscosity, an important feedback that we explored in this project. The objectives of the project were as follows: (1) measure the effects of molecular structure, temperature, and relative humidity on the viscosity of organic aerosol formed via controlled laboratory experiments, (2) measure the effects of organic aerosol viscosity on water uptake and CCN activity above and below water saturation, (3) further develop the κ parameterization of organic aerosol hygroscopicity to include viscosity/phase, and (4) experimentally validate the κ parameterization for organic aerosol with chemical composition ranging from relatively simple to complex. It was proposed that particle viscosity exerts a kinetic control on equilibrium water uptake. High viscosity was expected to delay water uptake based on diffusional limitations. This would manifest itself in reduced observed CCN activity or κ. Understanding the interplay between water content and viscosity (composition control on particle viscosity) and between viscosity and equilibrium water content (diffusional control on water uptake) were the overall science objectives of this grant. Targeted experiments were carried out to test the kinetic control hypothesis. These experiments included studies that explicitly measured the equilibration time scale of water uptake, and experiments that tested the role of viscous particle coatings on the observed CCN activity. From the combined work, it is concluded that mass transfer limitations by glassy organic particles are unlikely to affect cloud droplet activation near laboratory temperatures. This implies that viscosity does not need to be included in parameterizations that link particle chemical composition and κ. A parameterization to predict κ through the UNIFAC group contribution method was developed with previous ASR funding. As planned, this computational module was further developed and validated here through targeted laboratory studies. The computational module has been made available as free software under the GNU public license. A database of κ-values to aid model development has been compiled and is available online via an open access model. In conducting this work, significant effort was made to understand how aerosol composition, including the associated aerosol water content, affects viscosity. This included a study detailing the influence of functional group composition on organic aerosol viscosity. We identified a strong link between volatility and viscosity. Functional groups responsible for low vapor pressure also promote high viscosity. Specifically, carboxylic acid and hydroxyl groups were identified as major contributors to high viscosity. Several studies were carried out to characterize the link between composition and the glass-to-liquid phase transition. Compositions tested include models of organic/inorganic particles and models of complex organic aerosol formed through secondary processes. A simple computational model to predict the amorphous phase diagram was developed and tested. Excellent agreement between model and measurements was obtained for organic/inorganic mixtures. The computational model is simple enough to be included in global model simulations. However, constraints of input parameters such as the Gordon-Taylor constant for binary mixtures for a wide range of complex mixtures have not yet been fully evaluated. Combined, the performed work provides new constraints on the amorphous phase state of organic aerosols.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

CRADA 376 Final Report Development of Protective Coatings for 1 kW Hot Zone

Pacific Northwest National Laboratory (PNNL) has extensive experience in the development, fabrication, and evaluation of surface treatments and protective coatings for metallic solid oxide fuel cell (SOFC) components. For example, modified (Mn,Co)3O4 spinel coatings and coating/metal interfaces have been shown to substantially improve oxidation resistance, electrical performance, and oxide scale adhesion of ferritic stainless steel interconnects in planar SOFC stacks. At the time of the establishment of this CRADA, Protonex Technology Corporation had been working in the field of SOFC development for over 12 years and had demonstrated more than 250 thermal cycles with a less than 15 minutes start time and more than 2000 hours of continuous operation on a 250W tubular solid oxide hot zone module as part of a program for the Office of the Secretary of Defense (OSD). An industrial version of the military system, denoted P200i, had been developed that was launched at the 2015 Fuel Cell Expo in Tokyo. Feedback during beta testing of this unit was very positive. However, Protonex recognized that to transition from military markets, the commercial system would require longer life time and higher power. Leveraging their novel thermal management strategy from the tubular hot zone that allowed for rapid and repeated thermal cycling, Protonex developed a planar 1kW module aimed at the industrial and commercial market. However, more robust interconnect coatings were needed to bring the system into the 1000+ hour life time requested by customers. Therefore, PNNL’s experience and technology were engaged to enable the 1kw system to transition from military applications to commercial and industrial applications. In this CRADA, PNNL teamed with Protonex to leverage PNNL’s expertise in protective coating techniques for solid oxide fuel cell (SOFC) applications. As the first step in the collaboration, protective spinel coatings were fabricated at PNNL onto ten AISI 440 stainless steel bus bars provided by Protonex. A precursor slurry containing spinel powder was applied to the steel surfaces via an ultrasonic spray process. The coated bars were then subjected to a reducing atmosphere heat treatment (i.e., heated to 850°C at 3°C/min in a hydrogen atmosphere and held at that temperature for five hours). Five of the bars were left in this reduced condition; the other five bars were subjected to an oxidizing heat treatment (i.e., heated to 1000°C at 3°C/min in air and held at that temperature for one hour). The bars were then sent to Protonex for testing. Subsequently, Protonex decided to discontinue their SOFC development activities, so they had no further interest in continuing the collaboration with PNNL, and the CRADA activities were terminated.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2018

Advanced Control Architecture and Sensor Information Development for Process Automation, Optimization, and Imaging of Chemical Looping Systems

The Syngas Chemical Looping (SCL) process developed at The Ohio State University (OSU) uses an iron-based oxygen carrier to convert syngas into high-purity hydrogen while simultaneously capturing carbon dioxide that is readily sequestrable. A 25 kWth sub-pilot unit was successfully demonstrated multiple times on the OSU Clean Coal Research Facility, and a 250 kWth – 3 MWth pilot demonstration unit has been designed and constructed at the National Carbon Capture Center (NCCC) in Wilsonville, Alabama. The focus of this project is to develop multiple technologies to automate the startup and shutdown of chemical looping system. Success of this project will propel the advanced carbon capture method toward commercialization, hence be disruptive to the fossil fuel and power industries. Advanced process automation control architecture and imaging and optimization sensor software were developed for OSU chemical looping process. A high-level controller (HLC) consisting of decision-making and controller-selection logic integrated with sliding mode controllers (SMCs) were developed to perform chemical looping process startup and shutdown. Babcock & Wilcox Power Generation Group’s FocalPoint Optimization System was implemented to optimize the process operating conditions. The process automation controller and optimization information were realized and tested on OSU’s existing sub-pilot chemical looping test unit under atmospheric condition. The implemented control architecture was able to perform the complete process procedure from startup, steady-state reaction operation to shutdown with minimal operator intervention. The controller was also implemented on the pressurized syngas chemical looping (SCL) pilot test unit constructed at the National Carbon Capture Center (NCCC), demonstrating its pressure control capability with a designed transient state trajectory. An electrical capacitance volume tomography (ECVT) sensor device and its software were developed to image the packed moving bed and slugging fluidized bed of oxygen carriers in chemical looping systems at elevated temperatures. The ECVT device constructed was capable of tracking the subtle voidage variance along the moving bed axis as a feature for directly measuring the oxygen carrier particles’ linear velocity. Also, the high temperature ECVT device was used to study the fluidization characteristics of Geldart Group D particles.

08 HYDROGEN↗
DOE OSTI2018

Report on the completion of the development of processing map from as-cast Alloy 709 materials

This report provides details on the completion of the development of the processing map from the as-cast Alloy 709 materials. The report is a Level 4 deliverable in FY18 (M4NT18AN050502012), under the Work Package NT-18AN05050201, “A709 Development” performed by Argonne National Laboratory, as part of Advanced Structural Materials Program for the Advanced Reactor Technologies (ART). The report describes the development of a processing map to guide the development of hot work regimens for A709. The maps combine high-temperature flow stress measurements, described in a companion report by Oak Ridge National Laboratory, and metallographic observations, described here, into a single diagram that can be used to select hot working parameters to avoid regions of plastic instability and to avoid the development of unfavorable microstructures. This report describes the process of creating the map, provides the final map for A709, and uses the processing map to describe two potential hot work regimens that could be used in processing a DOE round ingot into bar stock.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2018

Multi-Physics Simulations for Molten Salt Reactor Evaluation: Chemistry Modeling and Database Development

To aid in design and licensing of molten salt reactors, a framework integrating the complex interaction of reactor neutronics, thermal hydraulics, and chemistry is being developed within the Department of Energy Advanced Reactor Technology Program’s Molten Salt Reactor (MSR) campaign. The challenges of integrating thermochemical and thermophysical behavior into a multi-physics reactor simulations include the following: (1) population of data needed for refinement of current models and development of nonexistent models through experimental measurements, first principles calculations, and development of a machine learning approach (2) thermochemical and thermophysical model development, (3) further development of Thermochimica, an open-source efficient equilibrium solver used to link thermochemical models to the multi-physics code, (4) a framework for integrating kinetic phenomena: nucleation, precipitation, mass/heat transport, and corrosion models, and (5) a computational environment to efficiently utilize the data and models within a multi-physics modeling tool. These challenges are being addressed through a collaboration among Oak Ridge National Laboratory, Argonne National Laboratory, the University of South Carolina, and the University of Ontario Institute of Technology.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2019

A Unified Ice Microphysical Parameterization for Numerical Models: Development and Testing with In-situ Data

The primary goal of the project is to develop and test new microphysical parameterizations of ice crystal growth. Over the past 7 years, we have developed a bulk ice microphysical model that evolves a measure of particle shape and density during vapor diffusional growth. The method allows smaller, pristine ice crystals to evolve into larger snow crystals in a more natural fashion than traditional microphysical schemes. In doing so, the new method avoids problems that occur when ice is transferred among pre-defined classes. The new model was developed and tested for vapor grown ice only, and so the goal of this project is to develop bulk parameterizations of the missing physics for the model including the prediction of surface deposition coefficients, riming, and aggregation. The parameterizations are being developed using prior laboratory data as a constraint, and then will be tested in simulations of case studies.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Long-Range Development Framework

The Long-Range Development Framework (LRDF) guides effective, efficient, and sustainable land and infrastructure development for Sandia National Laboratories’ (SNL) New Mexico and California campuses. The LRDF is SNL’s seminal site planning document. Similar to a municipal planning document, it articulates a long-range development vision, framework goals, and a set of integrated development principles for land use, security, transportation, and environmental sustainability. The LRDF is neither a project planning document, nor does it recommend or eliminate specific projects; rather, it introduces planning concepts and provides guidance regarding effective, efficient, and sustainable site development.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2019

Report on FY19 Testing in Support of Integrated EPP-SMT Design Methods Development

Experiments in support of the development of the integrated Elastic–Perfectly Plastic (EPP) analysis and Simplified Model Test (SMT) design methodology continued in FY 2019. Major progress was made in the verification of the newly developed two-bar SMT and single-bar SMT (SBSMT) methods by performing tests on Alloy 617 and SS 316H at high temperatures. Comparable results were achieved when the materials were tested under same conditions using both techniques. Because of its simple test configuration, SBSMT was the preferred testing technique used to evaluate elastic follow-up effect and generate data in support of SMT-based design curves. Evaluation of elastic follow-up was started with testing SS 316H at 815°C using SBSMT in this reporting period. As a result of this effort, the basic procedure and test protocol to provide data in support of the development of SMT-based design curves were established. This report also summarizes recent test results for the pressurization SMT using test articles with key features on Alloy 617 at intermediate strain ranges and at a low temperature of 850°C. Although more test results are needed in order to fully understand the effect of primary load on SMT creep-fatigue (CF) life, the limited test data indicate that the primary load reduced the SMT life at intermediate strain ranges and high temperatures. Recognizing the advantages of the newly developed SBSMT method, a new test geometry was designed to allow the elevation of the primary load effect on SMT CF life with the SBSMT technique. Additionally, selected tests were performed on SS 316H (heat 101076) to provide basic information about the heat of material. The tests performed included high-temperature tensile, fatigue, creep fatigue, and thermomechanical experiments. The results will be used to support the verification of the material constitutive model developed at Argonne National Laboratory.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Summary of Grizzly Development for Advanced Reactor Structural Materials

This summary report contains an overview of work performed during Fiscal Year 2019 under the Nuclear Engineering Advanced Modeling and Simulation (NEAMS) Fuels Product Line work package entitled "MS-19IN020106 - GRIZZLY - INL". Grizzly is a code based on the MOOSE framework that has been under development for several years funded by the US Department of Energy’s Light Water Reactor Sustainability (LWRS) program. Prior to 2019, Grizzly development was focused on development of capabilities needed to simulate the effects of aging mechanisms in light water reactor (LWR) components. The goal of this LWR-focused work has been to develop tools that can be used to assess the ability of existing LWRs to perform safety in long term operation (LTO) scenarios. This LWR-focused work has primarily focused on the effects of reactor pressure vessel (RPV) embrittlement and aging of reinforced concrete structures. Grizzly development to support LWR degradation needs is still ongoing, but starting in 2019, Grizzly’s capabilities are being expanded to also meet growing needs for a tool to address structural component integrity and degradation in advanced reactors. A simulation capability for advanced reactor components has many of the same basic requirements that one for LWRs does, such as the ability to solve coupled systems of partial differential equations that arise from the fact that many of the problems of interest involve multiple coupled physics. The materials issues also inherently involve multiple length scales, with the response at the engineering scale being strongly affected by mechanisms occurring at atomistic and mesoscopic scales.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2019

Development and Validation of Predictive Models for In-Cylinder Radiation and Wall Heat Transfer

The lack of accurate submodels for in-cylinder radiation and heat transfer has been identified as a key shortcoming in developing truly predictive, physics-based computational fluid dynamics (CFD) models that can be used to develop and design combustion systems for advanced high-efficiency, low-emissions engines. Measurements of wall boundary layers in engines show discrepancies of up to 100% with respect to standard CFD boundary layer models. And analysis of in-cylinder radiation based on the most recent spectral property databases and high-fidelity radiative transfer equation solvers has shown that at operating pressures and exhaust-gas recirculation levels typical of modern compression-ignition truck engines, molecular gas radiation (mainly carbon dioxide and water vapor) can be more important than soot particle radiation, and that a significant fraction of the emitted radiation (50% or more) can be reabsorbed before reaching the walls, thereby acting to redistribute energy in the combustion chamber. In this project, an integrated experimental and simulation approach has been used to generate new physical insight into in-cylinder heat-transfer processes in engines, and to develop computationally practicable CFD-based models that accurately represent the physics. New experimental data have been taken in an optically accessible single-cylinder research engine, and in a multi-cylinder production engine. Those data have provided new insight into the radiative environment in engines. New CFD models have been developed and validated for in-cylinder heat transfer, focusing mainly on radiative heat transfer and coupling between turbulent boundary layer wall heat transfer and radiative heat transfer. The CFD models have been developed and implemented in an open-source software framework that can be shared with other researchers. The models are compatible both with unsteady Reynolds-averaged Navier Stokes (URANS) formulations and with large-eddy simulations (LES) of in-cylinder processes in engines.

02 PETROLEUM↗
DOE OSTI2019

Materials genome enabled development of 3100ºF capable multilayer, multicomponent thermal and environmental barrier coatings for CMCs

In this STTR program, QuesTek Innovations LLC, a leader in the field of computational materials design, partnered with the University of Minnesota to expand its computational Materials by Design ® technology by developing a “design toolkit” that enables the subsequent design and development of novel, multilayer, multicomponent, high-performance T/EBC for CMC turbine components. In order to develop a T/EBC system capable of meeting all of the design requirements, this toolkit will then be applied to address critical technical challenges including developing a higher-temperature oxidation-resistant bondcoat while addressing thermo-chemical/mechanical compatibility between coating layers. QuesTek led the overall STTR program with the long-term objective to design and develop unique compositions to enable the application of T/EBCs for higher temperature gas turbines. Prof. David Poerschke from University of Minnesota (UMN) conducted experiments to support the design of high performance T/EBCs based on his expertise in the area of high-temperature oxidation and the environmental protection challenges involved in implementing SiC-CMC technology in gas turbine systems.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2019

Initial Development of an Improved Creep-Fatigue Design Method that Avoids the Separate Evaluation of Creep and Fatigue Damage and Eliminates the Requirement for Stress Classification

This report describes a method for capturing the effect of strain range, temperature, hold time, and elastic follow up on the cyclic life of a material undergoing uniaxial load. Developing design correlations of this type requires methods for extrapolating experimental data as a function of hold time and follow up factor. Various extrapolation methods are developed and discussed here and recommendations are developed for the final approaches to be adopted for design use. The report also describes comparisons between the new creep-fatigue design method, described here, and current creep-fatigue design methods in the ASME Boiler and Pressure Vessel Code and associated nuclear Code Cases. These comparisons demonstrate several advantages of the new method: it is easier to execute and is less over conservative than many current approaches. This report, along with a companion on extending these results to multiaxial load and on combining load cycles, represents the accumulation of several years of work on the development of this new approach to creep-fatigue design, combining an elastic perfectly plastic analysis method with simplified model tests measuring the effect of elastic follow up on creep-fatigue cyclic life. The conclusions to this report describe a path forward to developing the required design data for high temperature advanced reactor structural materials and guiding the adoption of the new method in the ASME Boiler and Pressure Vessel Code and related standards.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Distributed Accelerometer IMU-2: An Interim Development Report

This report details the development of DAIMU-2, a MEMS accelerometer-based Gyro-Free Inertial Measurement Unit (GF-IMU). Previously, a GF-IMU called the Distributed Accelerometer IMU (DAIMU) was developed at LLNL using traditional analog accelerometers. This project leverages the experience gained from DAIMU and recent advances in sensor and embedded systems technology to develop DAIMU-2. The report introduces the theory and mathematics of a GF-IMU, followed by the design of an Unscented Kalman Filter (UKF) and simulation results. Finally, the DAIMU-2 prototypes developed to date are presented. After approximately one year of development work, the project was suspended, to be resumed in the future. Because of this, some efforts were partially completed, and this report attempts to indicate areas where further work is needed. MATLAB files, drawings, and other design documents have been archived for future project resumption.

42 ENGINEERING↗
DOE OSTI2020

Development and Characterization of 3D-Printed Cementitious Sytems for Innovative Nuclear Systems

The Transformational Challenge Reactor (TCR) is being developed to demonstrate a revolutionary approach to deploying new nuclear power systems by building and operating an additively manufactured microreactor. This initiative provides a unique opportunity to investigate the possibility of taking advantage of the recent development of the 3D-printed concrete system using the Sky Big Area Additive Manufacturing (SkyBAAM) printer at the Manufacturing Demonstration Facility (MDF) at Oak Ridge National Laboratory. Two pathways have been pursued in parallel since the end of the second quarter of FY19: 1. Development of methods to characterize the performance of additive manufacturing concrete using traditional Portland-cement based solution, and 2. Investigation of the opportunity to develop innovation of printable materials with higher irradiation-resistance performance using nontraditional concrete solutions in favor of carbonated cementitious materials (CCMs). This report describes the results achieved to date for both pathways. The main results are listed below: 1. A test protocol has been established to characterize the fracture properties of 3D-printed concrete; this protocol will be used to assess the performance of printed traditional and nontraditional cementitious materials, with a focus on performance of the interfaces inherent to the additive manufacturing process. 2. A state-of-the-art review of the mechanisms, fabrication method, and performance of CCMs was conducted. CCMs appear to be a viable, highly innovative, more performant alternative to Portland-based cementitious solution for the erection of biological shield pending some materials development.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2020

Development and Validation of a Two-Phase Thermal-Hydraulic CFD Code NEK-2P

A project is underway to develop, verify and validate an advanced two-phase flow modeling capability for the highly-scalable, high-performance Computational Fluid Dynamics (CFD) code NEK5000. The goal of this work is to verify and validate the two-phase version of the NEK5000 code, named NEK-2P, to simulate the two-phase flow and heat transfer phenomena that occur in a Boiling Water Reactor (BWR) fuel bundle under various operating conditions. The NEK-2P two-phase flow models follow the approach used for the Extended Boiling Framework (EBF) previously developed at Argonne but include more fundamental physical models of boiling phenomena and advanced numerical algorithms for improved computational accuracy, robustness, and computational speed. The development of the NEK-2P two-phase solver and the implementation of the Extended Boiling Framework two-phase models were initially supported by Argonne National Laboratory (Argonne) through a Laboratory Directed Research and Development (LDRD) project during FY2014-2016. The development and validation of the two-phase models through analyses of selected two-phase boiling flow experiments was supported by the Nuclear Energy Advanced Modeling and Simulation (NEAMS) program in FY2017-2020. This report focuses on verification and validation of the water-steam boiling model NEK-2P Two-Phase, CFD code. The NEK-2P was validated with Nuclear Power Engineering Corporation (NUPEC) Pressurized Water Reactor (PWR) Sub-channel and Bundle Test (PSBT) void distribution benchmark. Three different simulations were performed and analyzed for various operating conditions such as wall-heat flux and sub-cooled inlet temperatures. Reasonably good agreement with measured data was obtained in predicting the measured void distributions. Simulations were performed for Virginia Tech. (VT) 3x3 rod bundle geometry with and without spacers. The preliminary results were presented for Simplified Spacer Grid (SSG). In addition, the implementation of interface reconstruction model was tested with one of the Becker benchmark Critical Heat Flux (CHF) experiments.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2020

Development of a Reference Model for Molten-Salt-Cooled Pebble-Bed Reactor Using SAM

To support the development and utilization of the SAM code for fluoride-salt-cooled high-temperature pebble-bed reactor (PB-FHR) safety analysis and licensing, an effort was devoted to developing reference models for PB-FHR primary loop and the reactor cavity cooling system (RCCS). A reference standard problem of a prototypical reactor design is foundational to NRC and industry to verify the adequacy of computer codes and evaluation models for a specific reactor type. The SAM code was enhanced for the reference PB-FHR model development, including a 1D-3D flow coupling scheme and conjugate heat transfer between porous media and solid structures. The reference FHR primary loop model was developed based on the UC Berkeley Mk1 FHR design with additional design features from the Kairos Power’s KP-FHR core. The PB-FHR core is modeled by a two-dimensional porous medium while the rest of the primary loop is represented by a SAM one-dimensional model. A SAM one-dimensional primary loop model was also developed for comparison using a single channel approach for the reactor core. Furthermore, the water-based NSTF cavity was modeled using SAM multi-dimensional flow module, to assist in evaluating SAM capabilities of modeling the emergency heat removal systems relying on RCCS concepts.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2020

Model Development for Multi-Component Fuel Vaporization and Flash Boiling

The objectives of this project are to improve the multi-component fuel droplet and film vaporization models used in internal combustion engine simulation, and to develop a comprehensive model to predict the characteristics of multi-component flash boiling spray. This work explores two approaches to fuel composition treatment for modeling multi-component fuel vaporization: one based on discretization and surrogates, and the other based on continuous thermodynamic distribution of fuel properties. The experimental data collected for model validation are done under three fuel form factors: droplet, spray, and thin film. The study on sprays also include experimentation under non-flash and flash boiling conditions, a phenomenon that enhances fuel vaporization. The main goals of this work are: Design and develop a multi-component fuel droplet and wall film vaporization model using both discrete and continuous thermodynamics methods. Design and develop an analytical model for multi-component flash boiling. Integrate the multi-component droplet and film model into multi-dimensional engine calculations to predict the fuel vaporization process under engine operation condition. Conduct multi-component droplet and fuel film vaporization experiments in a non-combusting chamber to verify the proposed vaporization models. Characterize flash boiling phenomena of multi-component fuel sprays by optical and laser diagnostic techniques. This report will detail the experimental setup and the numerical basis for developing a model to achieve the main goals listed above. Key features of observed multi-component fuel vaporization will be summarized at the end of each experimental sections, and corresponding model performance evaluation will be presented at the end of each model development section.

33 ADVANCED PROPULSION SYSTEMS↗