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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

Summary of GTD computer codes developed at the Ohio State University

This paper briefly describes three user-oriented computer codes developed at the Ohio State University ElectroScience Laboratory: namely, the On-Aircraft Antenna Code, the Basic Scattering Code, and the Reflector Antenna Code. Each code uses the Geometrical Theory of Diffraction (GTD). An example is used to describe the basic GTD approach for all three codes. A brief description is given for each code which includes sample results compared to measurements.

Burnside, W. D.↗
NASA NTRS1974

Operations analysis (study 2.1). Program listing for the LOVES computer code

A listing of the LOVES computer program is presented. The program is coded partially in SIMSCRIPT and FORTRAN. This version of LOVES is compatible with both the CDC 7600 and the UNIVAC 1108 computers. The code has been compiled, loaded, and executed successfully on the EXEC 8 system for the UNIVAC 1108.

Wray, S. T., Jr.↗
DOE OSTI2015

MELCOR Computer Code Manuals Volume 1: Primer and Users' Guide

MELCOR is a fully integrated, engineering-level computer code that models the progression of severe accidents in light water reactor nuclear power plants. MELCOR is being developed at Sandia National Laboratories for the U.S. Nuclear Regulatory Commission as a second-generation plant risk assessment tool and the successor to the Source Term Code Package. A broad spectrum of severe accident phenomena in both boiling and pressurized water reactors is treated in MELCOR in a unified framework. These include thermal-hydraulic response in the reactor coolant system, reactor cavity, containment, and confinement buildings; core heatup, degradation, and relocation; core-concrete attack; hydrogen production, transport, and combustion; fission product release and transport behavior. Current uses of MELCOR include estimation of severe accident source terms and their sensitivities and uncertainties in a variety of applications.

97 MATHEMATICS AND COMPUTING↗
NASA NTRS1979

Development of a Model and Computer Code to Describe Solar Grade Silicon Production Processes

The program aims at developing mathematical models and computer codes based on these models, which allow prediction of the product distribution in chemical reactors for converting gaseous silicon compounds to condensed-phase silicon. The major interest is in collecting silicon as a liquid on the reactor walls and other collection surfaces. Two reactor systems are of major interest, a SiCl4/Na reactor in which Si(l) is collected on the flow tube reactor walls and a reactor in which Si(l) droplets formed by the SiCl4/Na reaction are collected by a jet impingement method. During this quarter the following tasks were accomplished: (1) particle deposition routines were added to the boundary layer code; and (2) Si droplet sizes in SiCl4/Na reactors at temperatures below the dew point of Si are being calculated.

Srivastava, R.↗
NASA NTRS1982

STGSTK: A computer code for predicting multistage axial flow compressor performance by a meanline stage stacking method

A FORTRAN computer code is presented for off-design performance prediction of axial-flow compressors. Stage and compressor performance is obtained by a stage-stacking method that uses representative velocity diagrams at rotor inlet and outlet meanline radii. The code has options for: (1) direct user input or calculation of nondimensional stage characteristics; (2) adjustment of stage characteristics for off-design speed and blade setting angle; (3) adjustment of rotor deviation angle for off-design conditions; and (4) SI or U.S. customary units. Correlations from experimental data are used to model real flow conditions. Calculations are compared with experimental data.

Steinke, R. J.↗
NASA NTRS2005

Source Listings for Computer Code SPIRALI Incompressible, Turbulent Spiral Grooved Cylindrical and Face Seals

This is the source listing of the computer code SPIRALI which predicts the performance characteristics of incompressible cylindrical and face seals with or without the inclusion of spiral grooves. Performance characteristics include load capacity (for face seals), leakage flow, power requirements and dynamic characteristics in the form of stiffness, damping and apparent mass coefficients in 4 degrees of freedom for cylindrical seals and 3 degrees of freedom for face seals. These performance characteristics are computed as functions of seal and groove geometry, load or film thickness, running and disturbance speeds, fluid viscosity, and boundary pressures.

Walowit, Jed A.↗
DOE OSTI2016

Computer Codes V and V Tests with a Large-Scale Sodium Thermal-Hydraulic Test Facility (STELLA)

The Korea Atomic Energy Research Institute (KAERI) is carrying out the design of a 'Prototype Generation IV Sodium-cooled Fast Reactor (PGSFR)' in cooperation with Argonne National Laboratory (ANL) in the US. In regard to computer codes V and V, a large-scale sodium thermal-hydraulic test program is currently being progressed in parallel with the PGSFR design, which is called STELLA (Sodium Test Loop for Safety Simulation and Assessment). The final objective of this program is to collect a separate and integral effect test database to validate the safety analysis codes and other thermal hydraulic design codes. In the first phase of the STELLA program, the sodium component test loop (hereafter called STELLA-1) was constructed at the KAERI site, and it has been used for performance tests of key sodium heat exchangers in PGSFR. Since this sodium test loop is basically for separate effects tests to verify the performance of key sodium components, the test database obtained from STELLA-1 has been used for the V and V of safety codes as well as heat exchanger design codes. The second phase of the program aiming at an integral effect test is called STELLA-2, which will be used for synthetic review of the key safety issues of PGSFR. The basic and detailed design phases of the STELLA-2 test facility are underway in accordance with the specific design requirements reflecting the whole design features of PGSFR. The facility installation is scheduled to be completed by 2018. Then the main experiments including the start-up tests will begin and the first integral effect test database will be constructed by the end of 2019. Based on the STELLA-2 platform, a simulation of the PGSFR transient will be made to evaluate the plant dynamic behaviors and demonstrate the decay heat removal performance. Multi-dimensional effects coming from a large sodium pool system will be identified as well. The test database obtained from the STELLA-2 experiment will be used for the validation of the safety analysis codes and other thermal hydraulics codes, and this project finally contributes to the specific design phase of PGSFR. This paper presents both the results of heat transfer tests for the key sodium heat exchangers using STELLA-1 and the first results of heat exchanger design codes V and V. The recent progress of the engineering design for the STELLA-2 test section is introduced and its specific design parameters are also presented in this paper with detailed evaluation results of their scaling distortions. A large-scale sodium thermal-hydraulic test program (STELLA) was introduced with the specific activities for separate and integral effects tests. The test database obtained from STELLA-1 was successfully used to validate both the heat exchanger design and safety analysis codes. Specific design features of the integral effects test facility (STELLA- 2) with a scaling ratio of 1/5 in length and 1/125 in volume were also presented. Validation of the STELLA-2 facility design is underway using system codes and CFD tools. Dedicated water-mockup experiments to verify the scaling design of key subsystems are currently being conducted as well. (authors)

42 ENGINEERING↗
NASA NTRS2005

Upgrades of Two Computer Codes for Analysis of Turbomachinery

Major upgrades have been made in two of the programs reported in "ive Computer Codes for Analysis of Turbomachinery". The affected programs are: Swift -- a code for three-dimensional (3D) multiblock analysis; and TCGRID, which generates a 3D grid used with Swift. Originally utilizing only a central-differencing scheme for numerical solution, Swift was augmented by addition of two upwind schemes that give greater accuracy but take more computing time. Other improvements in Swift include addition of a shear-stress-transport turbulence model for better prediction of adverse pressure gradients, addition of an H-grid capability for flexibility in modeling flows in pumps and ducts, and modification to enable simultaneous modeling of hub and tip clearances. Improvements in TCGRID include modifications to enable generation of grids for more complicated flow paths and addition of an option to generate grids compatible with the ADPAC code used at NASA and in industry. For both codes, new test cases were developed and documentation was updated. Both codes were converted to Fortran 90, with dynamic memory allocation. Both codes were also modified for ease of use in both UNIX and Windows operating systems.

Chima, Rodrick V.↗
NASA NTRS1994

Computer code for controller partitioning with IFPC application: A user's manual

A user's manual for the computer code for partitioning a centralized controller into decentralized subcontrollers with applicability to Integrated Flight/Propulsion Control (IFPC) is presented. Partitioning of a centralized controller into two subcontrollers is described and the algorithm on which the code is based is discussed. The algorithm uses parameter optimization of a cost function which is described. The major data structures and functions are described. Specific instructions are given. The user is led through an example of an IFCP application.

Schmidt, Phillip H.↗
NASA NTRS1980

An evaluation of a computer code based on linear acoustic theory for predicting helicopter main rotor noise

Acoustic characteristics predicted using a recently developed computer code were correlated with measured acoustic data for two helicopter rotors. The analysis, is based on a solution of the Ffowcs-Williams-Hawkings (FW-H) equation and includes terms accounting for both the thickness and loading components of the rotational noise. Computations are carried out in the time domain and assume free field conditions. Results of the correlation show that the Farrassat/Nystrom analysis, when using predicted airload data as input, yields fair but encouraging correlation for the first 6 harmonics of blade passage. It also suggests that although the analysis represents a valuable first step towards developing a truly comprehensive helicopter rotor noise prediction capability, further work remains to be done identifying and incorporating additional noise mechanisms into the code.

Davis, S. J.↗
NASA NTRS1990

Computer codes for the evaluation of thermodynamic properties, transport properties, and equilibrium constants of an 11-species air model

The computer codes developed provide data to 30000 K for the thermodynamic and transport properties of individual species and reaction rates for the prominent reactions occurring in an 11-species nonequilibrium air model. These properties and the reaction-rate data are computed through the use of curve-fit relations which are functions of temperature (and number density for the equilibrium constant). The curve fits were made using the most accurate data believed available. A detailed review and discussion of the sources and accuracy of the curve-fitted data used herein are given in NASA RP 1232.

Thompson, Richard A.↗
NASA NTRS1982

A Computer Code for Swirling Turbulent Axisymmetric Recirculating Flows in Practical Isothermal Combustor Geometries

A primitive pressure-velocity variable finite difference computer code was developed to predict swirling recirculating inert turbulent flows in axisymmetric combustors in general, and for application to a specific idealized combustion chamber with sudden or gradual expansion. The technique involves a staggered grid system for axial and radial velocities, a line relaxation procedure for efficient solution of the equations, a two-equation k-epsilon turbulence model, a stairstep boundary representation of the expansion flow, and realistic accommodation of swirl effects. A user's manual, dealing with the computational problem, showing how the mathematical basis and computational scheme may be translated into a computer program is presented. A flow chart, FORTRAN IV listing, notes about various subroutines and a user's guide are supplied as an aid to prospective users of the code.

Lilley, D. G.↗
NASA NTRS2005

Source Term Model for Steady Micro Jets in a Navier-Stokes Computer Code

A source term model for steady micro jets was implemented into a non-proprietary Navier-Stokes computer code, OVERFLOW. The source term models the mass flow and momentum created by a steady blowing micro jet. The model is obtained by adding the momentum and mass flow created by the jet to the Navier-Stokes equations. The model was tested by comparing with data from numerical simulations of a single, steady micro jet on a flat plate in two and three dimensions. The source term model predicted the velocity distribution well compared to the two-dimensional plate using a steady mass flow boundary condition, which was used to simulate a steady micro jet. The model was also compared to two three-dimensional flat plate cases using a steady mass flow boundary condition to simulate a steady micro jet. The three-dimensional comparison included a case with a grid generated to capture the circular shape of the jet and a case without a grid generated for the micro jet. The case without the jet grid mimics the application of the source term. The source term model compared well with both of the three-dimensional cases. Comparisons of velocity distribution were made before and after the jet and Mach and vorticity contours were examined. The source term model allows a researcher to quickly investigate different locations of individual or several steady micro jets. The researcher is able to conduct a preliminary investigation with minimal grid generation and computational time.

Waithe, Kenrick A.↗
NASA NTRS1979

Fragmentation in a rotating protostar - A comparison of two three-dimensional computer codes

The collapse of an isothermal protostellar cloud with pressure, gravity, and rotation included is followed with two independent computer codes. For the initial condition, a nonaxisymmetric perturbation of mode m = 2 and 50% amplitude is introduced into a cloud of 1 solar mass with a mean density of 1.44 x 10 to the -17g/cu cm and a uniform angular velocity of 1.6 x 10 to the -12 rad/sec. The collapse is followed through an increase in density of over four orders of magnitude to the point where a binary protostar forms. The agreement between the results of the two calculations is good.

Boss, A. P.↗
NASA NTRS1996

A Comparison of Computer Codes for the Propagation of Sonic Booms Through Realistic Atmospheres Utilizing Actual Acoustic Signatures

A numerical exercise to compare computer codes for the propagation of sonic booms through the atmosphere is reported. For the initial portion of the comparison, artificial, yet realistic, waveforms were numerically propagated through identical atmospheres. In addition to this comparison, one of these codes has been used to make preliminary predictions of the boom generated from a recent SR-71 flight. For the initial comparison, ground waveforms are calculated using four different codes or algorithms: (1) weak shock theory, an analytical prediction, (2) SHOCKN, a mixed time and frequency domain code developed at the University of Mississippi, (3) ZEPHYRUS, another mixed time and frequency code developed at the University of Texas, and (4) THOR, a pure time domain code recently developed at the University of Texas. The codes are described and their differences noted.

Chambers, James P.↗
NASA NTRS1991

A high temperature fatigue life prediction computer code based on the Total Strain Version of Strainrange Partitioning (SRP)

A recently developed high-temperature fatigue life prediction computer code is presented, based on the Total Strain version of Strainrange Partitioning (TS-SRP). Included in this code are procedures for characterizing the creep-fatigue durability behavior of an alloy according to TS-SRP guidelines and predicting cyclic life for complex cycle types for both isothermal and thermomechanical conditions. A reasonably extensive materials properties database is included with the code.

Mcgaw, Michael A.↗
NASA NTRS1993

A high temperature fatigue life prediction computer code based on the total strain version of StrainRange Partitioning (SRP)

A recently developed high-temperature fatigue life prediction computer code is presented and an example of its usage given. The code discussed is based on the Total Strain version of Strainrange Partitioning (TS-SRP). Included in this code are procedures for characterizing the creep-fatigue durability behavior of an alloy according to TS-SRP guidelines and predicting cyclic life for complex cycle types for both isothermal and thermomechanical conditions. A reasonably extensive materials properties database is included with the code.

Mcgaw, Michael A.↗