scholarly journals Collaboration and Career Opportunities with Sandia National Laboratory.

2020 ◽  
Author(s):  
Diane Peebles
Keyword(s):  
National Laboratory ◽  
Sandia National Laboratory ◽  
Career Opportunities

scholarly journals Computational Analysis of the Performance Characteristics of a Supercritical CO2 Centrifugal Compressor

Computation ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 54 ◽  
Author(s):  
Senthil Raman ◽  
Heuy Kim
Keyword(s):  
Centrifugal Compressor ◽  
Stokes Equations ◽  
National Laboratory ◽  
Sandia National Laboratory ◽  
Ideal Gas ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Performance Characteristics ◽  
Supercritical Regime ◽  
Vaned Diffuser

A centrifugal compressor working with supercritical CO 2 (S-CO 2 ) has several advantages over other supercritical and conventional compressors. S-CO 2 is as dense as the liquid CO 2 and becomes difficult to compress. Thus, during the operation, the S-CO 2 centrifugal compressor requires lesser compression work than the gaseous CO 2 . The performance of S-CO 2 compressors is highly varying with tip clearance and vanes in the diffuser. To improve the performance of the S-CO 2 centrifugal compressor, knowledge about the influence of individual components on the performance characteristics is necessary. This present study considers an S-CO 2 compressor designed with traditional engineering design tools based on ideal gas behaviour and tested by SANDIA national laboratory. Three-dimensional, steady, viscous flow through the S-CO 2 compressor was analysed with computational fluid dynamics solver based on the finite volume method. Navier-Stokes equations are solved with K- ω (SST) turbulence model at operating conditions in the supercritical regime. Performance of the impeller, the main component of the centrifugal compressor is compared with the impeller with vaneless diffuser and vaned diffuser configurations. The flow characteristics of the shrouded impeller are also studied to analyse the tip-leakage effect.

Sensitivity Study of the South Texas Project Power Plant Steady-State Simulations Using RELAP5-3D Coupled With Dakota

2012 ◽  
Author(s):  
O. A. Rodriguez ◽  
R. Vaghetto ◽  
Y. A. Hassan
Keyword(s):  
Steady State ◽  
Power Plant ◽  
Uncertainty Quantification ◽  
National Laboratory ◽  
Sandia National Laboratory ◽  
Sensitivity Study ◽  
South Texas ◽  
Normal Operation ◽  
Inlet Temperature ◽  
The South

A RELAP5-3D input deck of the South Texas Project (STP) power plant was created in order to study the thermal-hydraulic behavior of the plant during normal operation (steady-state) and during a Loss of Coolant Accident (LOCA). It is important to study the sensitivity of selected output parameters such as the total coolant mass flow rate, the peak clad temperature, the secondary pressure, as a function of specific input parameters (reactor nominal power, vessel inlet temperature, steam generators primary side heat transfer coefficient, primary pressure etc.) in order to identify the variables that play a role in the uncertainty of the thermal-hydraulic calculations. RELAP5-3D, one of the most used best estimate thermal-hydraulic system codes, was coupled with DAKOTA, developed by Sandia National Laboratory for Uncertainty Quantification and Sensitivity Analysis in order to simplify the simulation process and the analysis of the results. In the present paper, the results of the sensitivity study for selected output parameters of the steady-state simulations are presented. The coupled software was validated by repeating one set of simulations using the RELAP5-3D standalone version and by analyzing the simulation results with respect of the physical expectations and behavior of the power plant. The thermal-hydraulic parameters of interest for future uncertainty quantification calculations were identified.

Linear Transformer Driver (LTD) development at Sandia national laboratory

2009 ◽  
Author(s):  
M. G. Mazarakis ◽  
S. Cordova ◽  
W. E. Fowler ◽  
K. L. LeChien ◽  
J. J. Leckbee ◽  
...  
Keyword(s):  
National Laboratory ◽  
Sandia National Laboratory ◽  
Linear Transformer Driver

Constitutive Modeling and Initial Validation of Cellular Concrete Subjected to Large Strains and High Strain Rates

2020 ◽  
Author(s):  
Brad G. Davis ◽  
Jared A. Dequenne
Keyword(s):  
National Laboratory ◽  
Sandia National Laboratory ◽  
Large Strains ◽  
Army Corps ◽  
Army Corps Of Engineers ◽  
Us Army ◽  
Weapon Systems ◽  
Using Data ◽  
Cellular Concrete ◽  
New Facilities

Abstract The development of lead-free small caliber weapon systems has inadvertently resulted in rounds with more material penetration capabilities. The increased penetration may mean that existing live-fire facilities will no longer be adequate for the training and certification of military and law enforcement personnel. Constraints on training in many live-fire shoot house facilities are already in place, with some allowing only single round impact during training. With no existing constitutive model for the cellular concrete commonly used in these facilities, it is not currently possible to analyze existing facilities or design new facilities against the most recent generation of ammunition currently being fielded. This project utilizes unconfined compression, uniaxial tension, triaxial confinement, and uniaxial strain from the US Army Corps of Engineers Engineer Research and Development Center and Sandia National Laboratory to characterize cellular concrete using a Holmquist-Johnson-Cook Concrete model for use in numerical simulations. This model is then initially validated using data from existing single projectile impact experiments against a similar material, showing results with reasonable accuracy. Additional experiments to fully validate the proposed model are discussed. This model provides the facility owner a potential tool to validate the safety of their facility against new projectiles and provides the designer of new facilities a tool for optimizing future configurations using these materials.

OVERVIEW OF ELECTROMECHANICAL AND OTHER METHODS OF ENERGY CONVERSION FOR EFFICIENT USE OF RESOURCES

2020 ◽  
pp. 57-73
Author(s):  
A.G. Logacheva ◽  
◽  
Y.N. Zatsarinnaya ◽  
E.G. Stepanova ◽  
E.V. Rep’ev ◽  
...  
Keyword(s):  
Energy Storage ◽  
Storage Systems ◽  
National Laboratory ◽  
Sandia National Laboratory ◽  
Energy Storage Systems ◽  
Cultural Economic ◽  
Social Sphere ◽  
Use Of Resources ◽  
Readiness Level ◽  
Storage Technologies

This article examines current trends in energy storage systems and their impact on social sphere, as well as the prospects for the development of energy storage systems until 2035. The purpose of this work is to analyze the existing energy storage technologies and the problems they solve in the world and in Russia. To do this, the authors of the article analyzed a database of 467 energy storage projects from the Sandia National Laboratory (DOE Global Energy Storage Database). Conducted research allowed us to assess the technology readiness level for main energy storage types. The political, socio-cultural, economic, legal, technological, environmental risks of the development of energy storage systems until 2035 have been determined.

Performance Evaluation of Novel Spline-Curved Blades of a Vertical Axis Wind Turbine Based on the Savonius Concept

2016 ◽  
Author(s):  
Michele Mari ◽  
Mauro Venturini ◽  
Asfaw Beyene
Keyword(s):  
Fluid Dynamic ◽  
National Laboratory ◽  
Sandia National Laboratory ◽  
Vertical Axis ◽  
Cfd Analysis ◽  
The Novel ◽  
Turbulent Model ◽  
Vertical Axis Wind Turbine ◽  
Laboratory Results ◽  
Central Shaft

In this study, we present the results of a two-dimensional fluid-dynamic simulation of novel rotor geometry with spline function which is derivative of the traditional S-shape Savonius blade. A Computational Fluid Dynamic (CFD) analysis is conducted using the Spalart-Allmaras turbulent model, validated using experimental data released by Sandia National Laboratory. Results are presented in terms of dimensionless torque and power coefficients, assuming a wind speed of 7 m/s and height and rotor diameter of 1 m. Furthermore, analysis of the forces acting on the rotor is conducted by evaluating frontal and side forces on each blade, and the resultant force acting on the central shaft. A qualitative representation of the vorticity around the traditional and spline rotor is shown to prove that the novel blade is more “flow-friendly”, thus the air flow is less turbulent through the rotor. Finally, energy conversion capability of the Savonius turbines is estimated in parametric form for both the traditional and spline-curved geometry.

scholarly journals Lawrence Livermore National Laboratory's activities to achieve ignition by X-ray drive on the National Ignition Facility

1999 ◽  
Vol 17 (2) ◽  
pp. 159-171 ◽  
Author(s):  
J.D. KILKENNY ◽  
T.P. BERNAT ◽  
B.A. HAMMEL ◽  
R.L. KAUFFMAN ◽  
O.L. LANDEN ◽  
...  
Keyword(s):  
Inertial Confinement Fusion ◽  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
Sandia National Laboratory ◽  
Department Of Energy ◽  
Naval Research ◽  
Inertial Confinement ◽  
National Ignition Facility ◽  
X Ray ◽  
Omega Laser

The National Ignition Facility (NIF) is a MJ-class glass laser-based facility funded by the Department of Energy which has achieved thermonuclear ignition and moderate gain as one of its main objectives. In the summer of 1998, the project was about 40% complete, and design and construction was on schedule and on cost. The NIF will start firing onto targets in 2001, and will achieve full energy in 2004. The Lawrence Livermore National Laboratory (LLNL) together with the Los Alamos National Laboratory (LANL) have the main responsibility for achieving X-ray driven ignition on the NIF. In the 1990s, a comprehensive series of experiments on Nova at LLNL, followed by recent experiments on the Omega laser at the University of Rochester, demonstrated confidence in understanding the physics of X-ray drive implosions. The same physics at equivalent scales is used in calculations to predict target performance on the NIF, giving credence to calculations of ignition on the NIF. An integrated program of work in preparing the NIF for X-ray driven ignition in about 2007, and the key issues being addressed on the current Inertial Confinement Fusion (ICF) facilities [(Nova, Omega, Z at Sandia National Laboratory (SNL) and NIKE at the Naval Research Laboratory (NRL)], are described.

Synchrotron Radiation Lithography for Manufacturing Integrated Circuits Beyond 100 nm

1998 ◽  
Vol 5 (3) ◽  
pp. 320-325
Author(s):  
Hiroo Kinoshita ◽  
Takeo Watanabe ◽  
Masato Niibe
Keyword(s):  
Integrated Circuits ◽  
Extreme Ultraviolet ◽  
Rapid Development ◽  
National Laboratory ◽  
Sandia National Laboratory ◽  
Measurement Technology ◽  
Extreme Ultraviolet Lithography ◽  
Ultraviolet Lithography ◽  
The Status ◽  
The Usa

Extreme ultraviolet lithography is a powerful tool for printing features of 0.1 µm and below; in Japan and the USA there is a growing tendency to view it as the wave of the future. With Schwarzschild optics, replication of a 0.05 µm pattern has been demonstrated in a 25 µm square area. With a two-aspherical-mirror system, a 0.15 µm pattern has been replicated in a ring slit area of 20 mm × 0.4 mm; a combination of this system with illumination optics and synchronized mask and wafer stages has enabled the replication of a 0.15 µm pattern in an area of 10 mm × 12.5 mm. Furthermore, in the USA, the Sandia National Laboratory has succeeded in fabricating a fully operational NMOS transistor with a gate length of 0.1 µm. The most challenging problem is the fabrication of mirrors with the required figure error of 0.28 nm. However, owing to advances in measurement technology, mirrors can now be made to a precision that almost satisfies this requirement. Therefore, it is time to move into a rapid development phase in order to obtain a system ready for practical use by the year 2004. In this paper the status of individual technologies is discussed in light of this situation, and future requirements for developing a practical system are considered.

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