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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,081 records · Page 60
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

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

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

Hover↗
NASA NTRSDate not supplied

Validation of Modis Cloud Liquid Water Path to Prepare for Pace Evaluation Efforts

The Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission will launch in January 2024, extending and improving NASA’s global satellite observations in its eponymous domains. PACE’s hyperspectral Ocean Color Instrument (OCI) will offer daily near-global spatial coverage with a 1.2 km horizontal pixel size at the subsatellite point. PACE will also have two multi-angle polarimeters (HARP2 and SPEXone) capable of advanced atmospheric characterization. Validation of cloud retrievals is challenging. Here we evaluate liquid water path (LWP) from MODIS from the standard (MOD06) product. The same cloud optical properties retrieval algorithm will be applied to OCI data. This will allow us to understand the expected performance of this algorithm and to develop the processing and analysis code needed to evaluate PACE data. Please tell us what you think and if we should be doing something differently!

MODIS↗
NASA NTRSDate not supplied

LS-DYNA User-Defined Internal Ballistic Modeling

- LS-DYNA Explicit Finite Element Analysis software and CADPROG Internal Ballistic Analysis code are integrated as a single modeling tool to analyze pyro-mechanical devices. - Combining these two codes allows the ballistic calculations to be performed without modeling the propellant in an FEA mesh. At each LS-DYNA time step, CADPROG is analytically run using the kinematic data (stroke, velocity, chamber volume) fed back from the LS-DYNA simulation. Calculated pressure is then applied to a piston or any applicable surface mesh in LS-DYNA model interactively. -All external loads such as friction, damping loads, assisting/resisting loads, locking/unlocking loads are modeled in LS-DYNA and coupled with pressure loads from CADPROG to create a fully defined equation of motion -Both codes are written in Fortran 77. CADPROG is inserted in LS-DYNA source code as a user-defined subroutine and re-compiled to generate a custom executable.

pyrotechnics↗
NASA NTRS2023

First VLTI/GRAVITY Observations of HIP 65426 b: Evidence for a Low or Moderate Orbital Eccentricity

Giant exoplanets have been directly imaged over orders of magnitude of orbital separations, prompting theoretical and observational investigations of their formation pathways. In this paper, we present new VLTI/GRAVITY astrometric data of HIP 65426 b, a cold, giant exoplanet which is a particular challenge for most formation theories at a projected separation of 92 au from its primary. Leveraging GRAVITY's astrometric precision, we present an updated eccentricity posterior that disfavors large eccentricities. The eccentricity posterior is still prior dependent, and we extensively interpret and discuss the limits of the posterior constraints presented here. We also perform updated spectral comparisons with self-consistent forward-modeled spectra, finding a best-fit ExoREM model with solar metallicity and C/O = 0.6. An important caveat is that it is difficult to estimate robust errors on these values, which are subject to interpolation errors as well as potentially missing model physics. Taken together, the orbital and atmospheric constraints paint a preliminary picture of formation inconsistent with scattering after disk dispersal. Further work is needed to validate this interpretation. Analysis code used to perform this work is available on GitHub: https://github.com/sblunt/hip65426.

Sarah Blunt↗
NASA NTRSDate not supplied

Overview of Rotor Hover Performance Capabilities at Low Reynolds Number for Mars Exploration

The Evolutionary aLgorithm for Iterative Studies of Aeromechanics (ELISA) software was developed in support of the Rotorcraft Optimization for the Advancement of Mars eXploration (ROAMX) project. ELISA was developed to enable aerodynamic rotor hover optimization for low Reynolds number flows in the Mars atmosphere. ELISA comprises two modules. The first module is dedicated to airfoil optimization and allows for the creation of multi-objective Pareto optimal (PO) airfoil sets with the airfoil performance evaluation performed using OVERFLOW. The second module is dedicated to rotor hover performance optimization and generates multi-objective PO rotor sets with the rotor performance evaluation performed using the comprehensive analysis code CAMRAD II. This paper presents recent updates to the ELISA optimization toolset. The airfoil module now includes variation in section Reynolds number, alongside simultaneous maximization of section lift and minimization of section drag. Consequently, the rotor optimization module can query PO airfoil sets (as a function of section lift, drag, and Reynolds number) and generate PO C81 decks tailored to specific Reynolds numbers, eliminating the need for adequate initial chord guesses and allowing for arbitrary rotor solidities to be studied. Furthermore, the rotor optimization has been extended to incorporate a third dimension, alongside maximization of blade loading and minimization of rotor power. This enables optimization across a relevant density range on Mars, presenting the lowest power rotor hover geometry, for each attainable blade loading, for each density. The goal of this work is to present the relevance of recent updates to the ELISA optimization toolset, by showing full rotor hover optimization using unconventional airfoils across a practical Mars density range, and by presenting various optimizations for changing blade numbers with unconstrained solidity in the Mars atmosphere.

Rotor↗
NASA NTRSDate not supplied

LS-DYNA User-Defined Internal Ballistic Modeling

One of the challenges in modeling deflagration of solid propellants with LS-DYNA is its limited capability, which is mostly applicable to airbag systems that use gaseous nitrogen generated by burning sodium azide. To overcome this limitation and enable the modeling of custom propellant grains with specific geometries, perforations, surface inhibitors, impetus, burn rates, and co-volumes, a user-defined burn model must be defined. In this study, a custom internal ballistic analysis code is integrated into LS-DYNA to simulate kinematic systems driven by pyro-mechanical devices such as pyro pushers, cutters, thrusters, separations bolts, ejection seat catapults, etc. Step-by-step guidance is provided on implementing a user-defined loading subroutine and the requirements for compiling a custom LS-DYNA executable along with a simple pyro thruster example.

pyrotechnics↗
NASA NTRSDate not supplied

LS-DYNA User-Defined Internal Ballistic Modeling

LS-DYNA Explicit Finite Element Analysis software and CADPROG Internal Ballistic Analysis code are integrated as a single modeling tool to analyze pyro-mechanical devices. Coupling these two codes allows the ballistic calculations to be performed without modeling the propellant in an FEA mesh. At each LS-DYNA time step, CADPROG is run analytically using the kinematic data (stroke, velocity, chamber volume) fed back from the LS-DYNA simulation. The calculated pressure is then applied to a piston or any applicable surface mesh in LS-DYNA model interactively. All external loads such as friction, damping loads, assisting/resisting loads, locking/unlocking loads are modeled in LS-DYNA and coupled with pressure loads from CADPROG to create a fully defined equation of motion Both codes are written in Fortran 77. CADPROG is integrated in the LS-DYNA source code as a user-defined subroutine and recompiled to generate a custom executable.

pyrotechnics↗
DOE OSTI2017

SOLVING CONJUGATE HEAT TRANSFER PROBLEM IN TWO-PHASE FLOW USING NEWTON-KRYLOV METHOD

In this paper, we successfully demonstrated an application of the Jacobian-free Newton Krylov (JFNK) method in solving the conjugated two-phase channel flow and heat conduction problem, in a fully coupled and fully implicit manner. Such a problem represents the most fundamental piece of safety analysis codes, for example the heat transfer between fuel rods and reactor coolant during postulated accidental scenarios. The two-phase flow is modeled with the widely accepted one-dimensional two-fluid two-phase flow model, and the heat conduction is modeled with two-dimensional heat conduction model. The coupling between these two physics is realized through the wall heat transfer term in fluid equations and heat flux boundary conditions of heat conduction model. For spatial discretization, both the first-order and second- order upwind schemes are considered for flow equations, while the standard central differencing method is used for the heat conduction model. For time integration, both the first-order backward Euler (BDF1) and second-order BDF2 schemes are considered. Several treatments were also introduced to enhance the robustness of the JFNK method in solving such a problem that is discontinuous in nature because of the discrete closure correlations. These treatments include the re-introduction of a transition region between the slug and annular mist flow regimes, and a simplification in the interfacial drag term. Numerical results have been extensively validated with experimental data in both vertical pipe and rod bundle geometries with a wide range of thermal-hydraulics conditions, including pressure, inlet subcooling, wall heat flux, outlet void fraction, and etc. Further benchmark with the RELAP5-3D code confirms the correct implementation of wall heat transfer models.

42 ENGINEERING↗
DOE OSTI2016

An Equation of State for Liquid Pb83Li17

Thermal hydraulic and accident analysis codes such as RELAP5-3D and MELCOR for Fusion rely on an equation of state to specify all the thermodynamic properties of fusion-relevant working fluids such as PbLi. The existing liquid metal fluid properties in both RELAP5-3D and MELCOR are based on a five parameter "soft sphere" equation of state for which parameter sets that approximately reproduce experiment data were available in the literature. The PbLi parameters were based on a linear, mass-weighted average of the parameters for pure Pb and pure Li, which does not always result in adequate agreement between the equation and experimental data for PbLi, much of which was not available at the time the original equations were implemented. In order to address this shortcoming, we describe here a modification and non-linear least squares fitting of the parameters to closely match available experiment data for the density, sound speed, and specific heat capacity of liquid PbLi over a range of temperatures. The new equation has been implemented in both RELAP5-3D and MELCOR, and we make comparisons with both codes to experiment data to verify the implementation. Transport properties such as the thermal conductivity and viscosity, though not derived from the equation of state, have also been updated.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2018

Flexible and Scalable Data-Acquisition Using the artdaq Toolkit

The Real-Time Systems Engineering Department of the Scientific Computing Division at Fermilab is developing a flexible, scalable, and powerful data-acquisition (DAQ) toolkit which serves the needs of experiments from bench-top hardware tests to large high-energy physics experiments. The toolkit provides data transport and event building capabilities with the option for experimenters to inject art analysis code at key points in the DAQ for filtering or monitoring. The toolkit also provides configuration management, run control, and low-level hardware communication utilities. Firmware blocks for several commercial data acquisition boards are provided, allowing experimenters to approach the DAQ from a high level. A fully-functional DAQ "solution" of the toolkit is provided in otsdaq, sacrificing some flexibility in favor of being ready-to-use. artdaq is being used for several current and upcoming experiments, and will continue to be refined and expanded for use in the next generation of neutrino and muon experiments.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2017

RISK MONITORING CAPABILITES FROM DYNAMIC PRA DATA

Risk Monitors (RMs) are software tools that are employed in nuclear power plants to monitor the safety properties of the plant itself during operation. These safety properties are generated using classical PRA methods which are typically based on static Boolean structures such as Fault-Trees (FTs) and Event-Trees (ETs). The outcomes of these methods are Core Damage Frequency (CDF) and risk importance values of plant components (e.g., valves and pumps). Examples of Risk Importance Measures (RIMs) commonly used are: Risk Achievement Worth (RAW), Risk Reduction Worth (RRW), Birnbaum (B) and Fussell-Vesely (FV) [1,2]. In a RM these values are updated in real time once plant components status is updated (e.g., under maintenance, off-line, testing). In addition, RMs can be used to optimize maintenance schedules so those safety features of the plant are below plant standard values. This paper presents an approach to create temporal profiles of RIMs (i.e., RM capabilities) given a temporal change of the plant configuration. Instead of employing data generated by ETs and FTs, the proposed approach will employ data generated by Dynamic PRA methods. In contrast to classical PRA methods, Dynamic PRA methods couple stochastic methods with safety analysis codes to determine risk associate to complex systems such as nuclear plants. Compared to classical PRA methods, they can evaluate with higher resolution the safety impact of timing and sequencing of events on the accident progression. We will describe how classical RIMs can be generated by Dynamic PRA data and then we will show how the temporal profiles of the RIMs can be generated given a temporal profile of the system configuration.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2018

Operation Data from the UW Natural Circulation FLiBe Flow Loop

Operating measurements from three multi-week test campaigns of the natural circulation FLiBe loop. This system is investigating thermal hydraulic behavior of the molten salt BeF_2 -LiF (33 - 67 mol %). The system behaves in a stable fashion, but shows unusual local transients, such as flow break-down in the riser and thermal jumps at the cooler exit. Heat transfer shows promising trends that FLiBe will behave as a normal heat transfer fluid, as long as salt purity can be maintained. The most recent test shows heat transfer degradation that is likely a result of oxides and impurities. The data archive contains as-built dimensions, Matlab analysis codes, and the raw data files.

42 ENGINEERING↗
DOE OSTI2019

Parfume (particle Fuel Model)

PARFUME is an advanced gas-cooled reactor fuel performance modeling and analysis code. It has been developed as an integrated mechanistic code that evaluates the thermal, mechanical, and physio-chemical behavior of fuel particles during irradiation and postulated accident conditions to determine the failure probability of a population of fuel particles given the particle-to-particle statistical variations in physical dimensions and material properties that arise from the fuel fabrication process, accounting for all viable mechanisms that can lead to particle failure. The code also determines the diffusion of fission products from the fuel through the particle coating layers, and through the fuel matrix to the coolant boundary. The subsequent release of fission products is calculated at the fuel element level (release of fission products from the compact or pebble). PARFUME calculates the release fraction as the ratio of the number of atoms released from the fuel element to the amount.

Gougar, Hans D.↗
DOE OSTI2019

NOBLE METAL MASS TRANSPORT MODEL FOR MOLTEN SALT REACTOR ANALYSIS IN VERA-CS

Molten Salt Reactor designs require robust multiphysics modelling capabilities to further the development of this next generation technology. Due to the unique liquid fuel design, traditional reactor physics analysis codes do not capture all of the important physics of these reactors. This work builds upon a general species transport model implemented into the multiphysics core simulator suite VERA-CS, by adding source and sink models for non-soluble fission products, specifically the noble metals. Noble metal fission products are born in the fuel-salt, but do not form stable fluorides, and instead plate out on various surfaces in the reactor fuel loop. A concentration gradient diffusion-convection based mass transfer model is implemented into the general species transport model within CTF-the subchannel thermal hydraulics code in VERA-CS-and verified. Two noble metal decay chains are analyzed, and their steady state bulk and surface concentrations are calculated for a simple flow loop in CTF that is representative of the Oak Ridge National Laboratory Molten Salt Reactor Experiment (MSRE). Non-soluble species 99Mo to 99Tc captures wall plate out of decaying species, and non-soluble 135Te to soluble 135I and gaseous 135Xe captures wall loss of decaying species. Results are compared with MSRE data and the possible multiphysics effects of this phenomena are identified. Future work to enhance the robustness of the physical model and couple it with neutronics to evaluate these effects of Noble Metal mass transport is discussed.

Walker, Samuel↗
DOE OSTI2021

Analysis of PNAR Spent Fuel Safeguards Measurements using the ORIGEN Data Analysis Module

This paper summarizes the analysis of the Passive Neutron Albedo Reactivity (PNAR) measurements using the ORIGEN data analysis module for 23 boiling water reactor spent fuel assemblies that were performed in Finland under an international collaboration on spent fuel safeguards verification methods. PNAR is part of the proposed integrated nondestructive system to be used for safeguards verifications at the planned Finnish encapsulation facility. Besides measuring passive neutron and gamma emission rates from an assembly like a Fork detector, PNAR also measures the PNAR ratio, which is expected to correlate with the fissile content in the assembly. The emission rates and PNAR ratio can be used to verify the operator declarations and the fissile content of an assembly, respectively. The analysis was performed using the ORIGEN Data Analysis Module, which was originally developed for predicting Fork detector neutron and gamma signals for spent fuel measurements and has been integrated into the Integrated Review and Analysis Package developed by Euratom and the IAEA. The Module includes the ORIGEN burnup analysis code and integrates detector response functions pre-generated using MCNP to predict detector signals in several seconds per assembly. In this study, new response functions specific to PNAR measurements were generated for ORIGEN Module. The study also analyzes impacts of using detailed fuel design and operation information vs. standard safeguards information on results calculated by ORIGEN Module. Using detailed information reduced the standard deviation of relative differences between calculated and measured neutron count rates among the 23 assemblies from ~10% to ~4%. The results obtained using standard safeguards information for these PNAR measurements were similar to those obtained for the Fork detector. A clear trend was found between the calculated net neutron multiplications and the measured PNAR ratios of the 23 assemblies. This paper describes how ORIGEN Module calculates the expected PNAR neutron and gamma signals and PNAR ratio and how they compare with corresponding measured values.

Ilas, Germina↗
DOE OSTI2022

Design of a Test Article and Test Facility to Investigate Flow-Induced Vibration of a Helical Coil Steam Generator

NuScale Power LLC (NuScale) is developing a small modular reactor (SMR) with unique design features and arrangements that require testing to provide quality data for safety analysis codes and design validation, as well as for technology maturation. A multi-phase testing program is underway at NuScale to demonstrate that its unique helical coil steam generator design is not susceptible to flow-induced vibration during operation. The phases of the testing program include modal testing of individual tubes during test article fabrication and modal and flow testing after test article completion. NuScale has contracted SIET S.p.A. in Piacenza, Italy for the design and fabrication of the test article and test facility. In-fabrication testing was performed at the site of test article build in Cremosano, Italy. Modal testing and flow testing of the completed test article will be performed at SIET’s facilities in Piacenza. This paper discusses the design of the test article and test facility, including supporting systems, required to generate the quality data required to support NuScale’s comprehensive vibration assessment program as part of the overall licensing effort for NuScale’s first-of-a-kind small modular light water reactor.

Flow-induced vibration, helical coil, steam genera↗
DOE OSTI2021

Radial Compressor Design and Off-Design for Trans-critical CO2 Operating Conditions

Presentation for the The 7th International Supercritical CO2 Power Cycles Symposium, February 21 – 24, 2022, San Antonio, Texas. A multi-staged intercooled centrifugal compressor design is performed for an indirect-fired sCO2 cycle and the design point data are used to generate the performance maps using a 2D mean-line analysis code. Fluid and turbomachinery similarity laws are applied to find an appropriate surrogate ideal gas fluid to be used in the design and performance map generation codes. The performance maps are then scaled back for the sCO2 fluid case using the affinity laws.

Uysal, Selcuk Can↗
DOE OSTI2021

Radial Compressor Design and Off-Design for Trans-critical CO2 Operating Conditions

A multi-staged intercooled centrifugal compressor design is performed for an indirect-fired sCO2 cycle and the design point data are used to generate the performance maps using a 2D mean-line analysis code. Fluid and turbomachinery similarity laws are applied to find an appropriate surrogate ideal gas fluid to be used in the design and performance map generation codes. The performance maps are then scaled back for the sCO2 fluid case using the affinity laws. The developed methodology is validated using the experimental data for a compressor operating at similar inflow conditions.

Uysal, Selcuk Can↗