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At least 127 records · Page 7

All sources NASA NTRS DOE OSTI

DOE OSTI2011

Convective Heating of the LIFE Engine Target During Injection

Target survival in the hostile, high temperature xenon environment of the proposed Laser Inertial Fusion Energy (LIFE) engine is critical. This work focuses on the flow properties and convective heat load imposed upon the surface of the indirect drive target while traveling through the xenon gas. While this rarefied flow is traditionally characterized as being within the continuum regime, it is approaching transition where conventional CFD codes reach their bounds of operation. Thus ANSYS, specifically the Navier-Stokes module CFX, will be used in parallel with direct simulation Monte Carlo code DS2V and analytically and empirically derived expressions for heat transfer to the hohlraum for validation. Comparison of the viscous and thermal boundary layers of ANSYS and DS2V were shown to be nearly identical, with the surface heat flux varying less than 8% on average. From the results herein, external baffles have been shown to reduce this heat transfer to the sensitive laser entrance hole (LEH) windows and optimize target survival independent of other reactor parameters.

42 ENGINEERING↗

DOE OSTI2014

Design and Integrate Improved Systems for Nuclear Facility Ventilation and Exhaust Operations

Objective: The objective of this R&D project would complete the development of three new systems and integrate them into a single experimental effort. However, each of the three systems has stand-alone applicability across the DOE complex. At US DOE nuclear facilities, indoor air is filtered and ventilated for human occupancy, and exhaust air to the outdoor environment must be regulated and monitored. At least three technical standards address these functions, and the Los Alamos National Laboratory would complete an experimental facility to answer at least three questions: (1) Can the drag coefficient of a new Los Alamos air mixer be reduced for better operation in nuclear facility exhaust stacks? (2) Is it possible to verify the accuracy of a new dilution method for HEPA filter test facilities? (3) Is there a performance-based air flow metric (volumetric flow or mass flow) for operating HEPA filters? In summary, the three new systems are: a mixer, a diluter and a performance-based metric, respectively. The results of this project would be applicable to at least four technical standards: ANSI N13.1 Sampling and Monitoring Releases of Airborne Radioactive Substances from the Stacks and Ducts of Nuclear Facilities; ASTM F1471 Standard Test Method for Air Cleaning Performance of a High-Efficiency Particulate Air Filter System, ASME N511: In-Service Testing of Nuclear Air Treatment, Heating, Ventilating, and Air-Conditioning Systems, and ASME AG-1: Code On Nuclear Air And Gas Treatment. All of the three proposed new systems must be combined into a single experimental device (i.e. to develop a new function of the Los Alamos aerosol wind tunnel). Technical Approach: The Radiation Protection RP-SVS group at Los Alamos has an aerosol wind tunnel that was originally (2006) designed to evaluate small air samplers (cf. US EPA 40 CFR 53.42). In 2009, the tunnel was modified for exhaust stack verifications per the ANSI N13.1 standard. In 2010, modifications were started on the wind tunnel for testing HEPA filters (cf. ASTM F1471 and ASME N511). This project involves three systems that were developed for testing the 24*24*11 (inch) HEPA filters (i.e. the already mentioned mixer, diluter and metric). Prototypes of the mixer and the diluter have been built and individually tested on a preliminary basis. However, the third system (the HEPA metric method) has not been tested, since that requires complete operability of the aerosol wind tunnel device. (The experimental wind tunnel has test aerosol injection, control and measurement capabilities, and can be heated for temperature dependent measurements.) Benefits: US DOE facilities that use HEPA filters and/or require exhaust stacks from their nuclear facility buildings will benefit from access to the new hardware (mixer and diluter) and performance-based metric (for HEPA filter air flow).

61 RADIATION PROTECTION AND DOSIMETRY↗

DOE OSTI2015

Multiaxial Creep-Fatigue and Creep-Ratcheting Failures of Grade 91 and Haynes 230 Alloys Toward Addressing Design Issues of Gen IV Nuclear Power Plants

The proposed research will develop systematic sets of uniaxial and multiaxial experimental data at a very high temperature (850-950°C) for Alloy 617. The loading histories to be prescribed in the experiments will induce creep-fatigue and creep-ratcheting failure mechanisms. These experimental responses will be scrutinized in order to quantify the influences of temperature and creep on fatigue and ratcheting failures. A unified constitutive model (UCM) will be developed and validated against these experimental responses. The improved UCM will be incorporated into the widely used finite element commercial software packages ANSYS. The modified ANSYS will be validated so that it can be used for evaluating the very high temperature ASME-NH design-by-analysis methodology for Alloy 617 and thereby addressing the ASME-NH design code issues.

36 MATERIALS SCIENCE↗

DOE OSTI2014

Neutron Sources for Standard-Based Testing

The DHS TC Standards and the consensus ANSI Standards use 252 Cf as the neutron source for performance testing because its energy spectrum is similar to the 235 U and 239 Pu fission sources used in nuclear weapons. An emission rate of 20,000 ± 20% neutrons per second is used for testing of the radiological requirements both in the ANSI standards and the TCS. Determination of the accurate neutron emission rate of the test source is important for maintaining consistency and agreement between testing results obtained at different testing facilities. Several characteristics in the manufacture and the decay of the source need to be understood and accounted for in order to make an accurate measurement of the performance of the neutron detection instrument. Additionally, neutron response characteristics of the particular instrument need to be known and taken into account as well as neutron scattering in the testing environment.

07 ISOTOPE AND RADIATION SOURCES↗

DOE OSTI2016

Respirators: Supervisors Self-Study #43442

This course, Respirators: Supervisors Self-Study (#43442), addresses training requirements for supervisors of respirator wearers as specified by the American National Standard Institute (ANSI) Standard for Respiratory Protection, ANSI Z88.2, and as incorporated by reference in the Department of Energy (DOE) Worker Health and Safety Rule, 10 Code of Federal Regulations (CFR) 851. This course also presents the responsibilities of supervisors of respirator wearers at Los Alamos National Laboratory (LANL).

99 GENERAL AND MISCELLANEOUS↗

DOE OSTI2017

Nanotechnology Standardization Activities – Support of U.S. Representation on ISO/TC 229 Nanotechnologies

In carrying out its responsibilities on behalf of the United States, ANSI provides comprehensive, administrative support and expertise on international protocols and procedures to: (1) the U.S. Technical Advisory Group (TAG) to the International Organization for Standardization’s (ISO) Technical Committee (TC) 229 Nanotechnologies, and (2) the corresponding U.S. TAG Working Groups tasked with formulating U.S. positions on topics relevant to nanotechnology standardization. Additionally, secretariat and procedural support is provided for the ISO/TC 229 WG 3 on health, safety and environment, for which the United States was assigned leadership by the participating national body members of ISO/TC 229. As the official entity that serves as the U.S. representative to ISO, ANSI provides not only expert coordination of U.S. positions and representation at ISO but also strategic direction, advice and procedural expertise to facilitate navigation of international issues to promote U.S. positions for incorporation into the ISO/TC 229 program of work necessary to support U.S. objectives.

77 NANOSCIENCE AND NANOTECHNOLOGY↗

DOE OSTI2017

Los Alamos National Laboratory Meteorology Monitoring Program: 2016 Data Completeness/ Quality Report

This report summarizes data completeness by tower and by instrument for 2016 and compares that data with the Los Alamos National Laboratory (LANL) and American National Standards Institute (ANSI) 2015 standards. This report is designed to make data users aware of data completeness and any data quality issues. LANL meteorology monitoring goals include 95% completeness for all measurements. The ANSI 2015 standard requires 90% completeness for all measurements. This report documents instrument/tower issues as they impact data completeness.

58 GEOSCIENCES↗

DOE OSTI2018

Fibre Channel Development Final Report CRADA No. TC-0340-92-D

The Fibre Channel (FC) Development project was designed to enhance U.S. industrial competitiveness by accelerating the standardization and subsequent industrial acceptance of the American National Standards Institute’s (AIW) Fibre Channel Standard (now X3T1 1). It was also intended to give the principal U.S. participants a one- to two-year lead in developing heterogeneous high-speed computer networks, dktibuted computing through clustering, scientific visualization techniques, and high speed channels. The project was proposed to benefit U.S. industry as these high performance computing methods became generally available. In 1992-93, during the initial project phases, Fibre Channel PC) was emerging as a new ANSI standard. It was envisioned as becoming the mechanism for data transfer between the next generation of computers, and between these computers and their peripherals. Using this channel standard, U.S. computer vendors were expecting to be able to provide high-speed interoperability between heterogeneous computers and their storage devices, with data transfer rates greater than a GBit/sec. Our project was composed of key principal players in the FC standardization effort from both U.S. industry and the Department of Energy’s (DOES) Lawrence Liverrnore National Laboratory (LLNL). The industial participants were developing individual FC interfaces to operate with their platform products. LLNL’s role was to be a neutral testing site and a facilitator for helping to resolve conflicting interpretations of the embryonic Fibre Channel specification. LLNL anticipated that conflicts in the interpretation of such a standard would arise and require neutral resolution and that such resolutions would best be achieved in cooperation with the ANSI FC Working Group. Project plans included transferring to U.S. industry any resilient FC testing capabilities at the project conclusion.

42 ENGINEERING↗

DOE OSTI2018

Los Alamos National Laboratory Meteorology Monitoring Program: 2017 Data Completeness/Quality Report

This report summarizes data completeness by tower and by instrument for 2017 and compares that data with the Los Alamos National Laboratory (LANL) and American National Standards Institute (ANSI) 2015 standards. This report is designed to make data users aware of data completeness and any data quality issues. LANL meteorology monitoring goals include 95% completeness for all measurements. The ANSI 2015 standard requires 90% completeness for all measurements. This report documents instrument/tower issues as they impact data completeness.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2019

Los Alamos National Laboratory Meteorology Monitoring Program: 2018 Data Completeness/Quality Report

This report summarizes data completeness by tower and by instrument for 2018 and compares that data with the Los Alamos National Laboratory (LANL) and American National Standards Institute (ANSI) 2015 standards. This report is designed to make data users aware of data completeness and any data quality issues. LANL meteorology monitoring goals include 95% completeness for all measurements. The ANSI 2015 standard requires 90% completeness for all measurements. This report documents instrument/tower issues as they impact data completeness.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2024

Annual Performance Testing of Tracer Gas Detectors for use in Radionuclide NESHAP Compliance Testing

Los Alamos National Laboratory’s (LANL’s) compliance with Radionuclide NESHAP0F 1 regulations is managed by the Radioactive Air Emissions Management (RAEM) team, part of LANL’s Compliance Programs group (EPC-CP). One area of the Radionuclide NESHAP addresses requirements for siting a stack sample system. Prior to commissioning a new stack sampling system, the ANSI Standard for stack sampling requires that the stack sample location must meet several criteria, including uniform mixing of tracer gas (sulfur hexafluoride, SF 6 ) and tracer aerosol (liquid oil droplets) in the air stream. This memorandum will specifically focus on the tracer gas portion of the ANSI Standard. For these mix tests, tracer gas is injected into the stack air stream and the resulting air concentrations are measured across the plane of the stack at the proposed sampling location. The coefficient of variation of the media concentration must be under 20% when evaluated over the central 2/3 area of the stack or duct.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2023

A numerical investigation of coal particle modeling for the inlet section of a pressurized oxy-combustion burner

Concerns over climate change have led to numerous efforts to develop low-carbon technologies, and pressurized oxy-combustion (POC) is a promising candidate to reduce carbon emissions in the power industry. Designing an effective burner for such technologies is vital for the development of these and other coal combustion technologies. Because of the high pressure, the volume fraction of coal particles at the fuel inlet of the pressurized oxy-combustor burner is close to or even higher than the maximum limit for commercial CFD codes (e.g., ANSYS FLUENT). At these high particle volume fractions, the interactions among particles, fluid flow and wall need to be re-evaluated. The present computational work is a first step in a systematic analysis of the influence of various parameters, like method of particle release, release location, and particle size, in a pilot-scale POC combustor, developed at Washington University in St. Louis (WUSTL). In the POC process, pulverized coal is burned under elevated pressure in an O2-CO2 environment. Specifically, a 15-bar, 100 kWth, POC combustor is modeled employing Ansys FLUENT commercial sodtware using the Reynolds-Averaged Navier-Stokes (RANS) approach. It is revealed that for this pilot-scale, pressurized burner, velocity profiles in the near-wall region exhibit some anomalies. In order to investigate the influence of particle loading in the near-wall region, particle release location was investigated. The numerical simulations incorporate the coupling between the turbulent flow and the particles. A sensitivity investigation of particle release location found that by tuning the release location, the velocity profile can be consistent with the pure gas flow velocity profile. More importantly, the particle releasing location also affects flame stability. Particle size was also found to have a significant impact on particle trajectory, flame stability and temperature. Finally, Large Eddy Simulations (LES) were performed and compared with the results from two-dimensional RANS.

Li, Lei↗

DOE OSTI2022

Impact of particle size and particle-flow-wall coupling on pressurized oxy-combustion in the down-fired burner

Concerns over climate change have led to numerous efforts in developing low-carbon energy technologies. Pressurized oxy-combustion (POC) is a promising candidate to reduce carbon emissions in power generation. Designing an effective burner plays a vital role in developing new coal combustion technologies. Because of the high pressure, the volume fraction of coal particles at the fuel inlet of the burner of a pressurized oxy-combustor is close or even higher than the maximum limit that commercial CFD codes (e.g., ANSYS FLUENT) can handle. At this high particle volume fraction, the interactions among particles, fluid flow, and wall need to be re-evaluated. The present computational work is the first step of a systematic analysis of the particle influence, like releasing method, releasing locating, and particle size, in a pilot-scale POC combustor, developed at Washington University in St. Louis (WUSTL). In a POC process, pulverized coal is burned under elevated pressure and O2-CO2 environment. Specifically, a 15-bar, 100 kWth, POC combustor is modeled employing ANSYS FLUENT, using Reynolds-averaged Navier-Stokes (RANS) modeling. It is revealed that for this pilot-scale, pressurized burner, velocity profiles of the near-wall region in this POC facility exhibit some discrepancy against the near-wall turbulent flow velocity profile. In order to investigate the particle influence in the near-wall region, particle releasing location will be investigated. Numerical simulation results exhibit the coupling effect of turbulence flow and particles in this case. The particle size also demonstrates a great effect on particle trajectory, then further has an impact on flame stability and temperature.

Li, Lei↗

NASA NTRS1980

Structured FORTRAN preprocessor

Structured-programming features simplify software design. Programmer needs only few control statements to code program in format easy to debug and maintain, freeing him/her from flow constraints of standard FORTRAN. Program is written in ANSI FORTRAN and is compatible with machine supporting FORTRAN compiler that accepts ANSI statements. It has been implemented on IBM 370.

Austin, S.↗

NASA NTRS1984

Low-frequency sound absorption measurements in air

Thirty sets of sound absorption measurements in air at a pressure of 1 atmosphere are presented at temperatures from 10 C to 50 C, relative humidities from 0 to 100 percent, and frequencies from 10 to 2500 Hz. The measurements were conducted by the method of free decay in a resonant tube having a length of 18.261 m and bore diameter of 0.152 m. Background measurements in a gas consisting of 89.5 percent N2 and 10.5 percent Ar, a mixture which has the same sound velocity as air, permitted the wall and structural losses of the tube to be separated from the constituent absorption, consisting of classical rotational and vibrational absorption, in the air samples. The data were used to evaluate the vibrational relaxation frequencies of N2 and/or O2 for each of the 30 sets of meteorological parameters. Over the full range of humidity, the measured relaxation frequencies of N2 in air lie between those specified by ANSI Standard S1.26-1978 and those measured earlier in binary N2H2O mixtures. The measured relaxation frequencies could be determined only at very low values of humidity, reveal a significant trend away from the ANSI standard, in agreement with a prior investigation.

Zuckerwar, A. J.↗

NASA NTRS1985

Low-frequency absorption of sound in air

Zuckerwar, A. J.↗

NASA NTRS1989

Space Shuttle Main Engine structural analysis and data reduction/evaluation. Volume 2: High pressure oxidizer turbo-pump turbine end bearing analysis

The high-pressure oxidizer turbopump (HPOTP) consists of two centrifugal pumps, on a common shaft, that are directly driven by a hot-gas turbine. Pump shaft axial thrust is balanced in that the double-entry main inducer/impeller is inherently balanced and the thrusts of the preburner pump and turbine are nearly equal but opposite. Residual shaft thrust is controlled by a self-compensating, non-rubbing, balance piston. Shaft hang-up must be avoided if the balance piston is to perform properly. One potential cause of shaft hang-up is contact between the Phase 2 bearing support and axial spring cartridge of the HPOTP main pump housing. The status of the bearing support/axial spring cartridge interface is investigated under current loading conditions. An ANSYS version 4.3, three-dimensional, finite element model was generated on Lockheed's VAX 11/785 computer. A nonlinear thermal analysis was then executed on the Marshall Space Flight Center Engineering Analysis Data System (EADS). These thermal results were then applied along with the interference fit and bolt preloads to the model as load conditions for a static analysis to determine the gap status of the bearing support/axial spring cartridge interface. For possible further analysis of the local regions of HPOTP main pump housing assembly, detailed ANSYS submodels were generated using I-DEAS Geomod and Supertab (Appendix A).

Sisk, Gregory A.↗

NASA NTRS1989

Nonlinear mesomechanics of composites with periodic microstructure

This work is concerned with modeling the mechanical deformation or constitutive behavior of composites comprised of a periodic microstructure under small displacement conditions at elevated temperature. A mesomechanics approach is adopted which relates the microimechanical behavior of the heterogeneous composite with its in-service macroscopic behavior. Two different methods, one based on a Fourier series approach and the other on a Green's function approach, are used in modeling the micromechanical behavior of the composite material. Although the constitutive formulations are based on a micromechanical approach, it should be stressed that the resulting equations are volume averaged to produce overall effective constitutive relations which relate the bulk, volume averaged, stress increment to the bulk, volume averaged, strain increment. As such, they are macromodels which can be used directly in nonlinear finite element programs such as MARC, ANSYS and ABAQUS or in boundary element programs such as BEST3D. In developing the volume averaged or efective macromodels from the micromechanical models, both approaches will require the evaluation of volume integrals containing the spatially varying strain distributions throughout the composite material. By assuming that the strain distributions are spatially constant within each constituent phase-or within a given subvolume within each constituent phase-of the composite material, the volume integrals can be obtained in closed form. This simplified micromodel can then be volume averaged to obtain an effective macromodel suitable for use in the MARC, ANSYS and ABAQUS nonlinear finite element programs via user constitutive subroutines such as HYPELA and CMUSER. This effective macromodel can be used in a nonlinear finite element structural analysis to obtain the strain-temperature history at those points in the structure where thermomechanical cracking and damage are expected to occur, the so called damage critical points of the structure.

Walker, Kevin P.↗