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Quench detection by fluid dynamic means in cable-in-conduit superconductors

Description: The tight confinement of the helium in cable-in-conduit superconductors creates protection problems because of the substantial pressure rise that can occur during a quench. But the same pressure rise offers the useful possibility of a non-electrical means of detecting incipient quenches by monitoring the outflow from the various hydraulic paths of the magnet. If the method is to work, the signal must be large enough to be detected unambiguously at an early enough time, and the signal must not d… more
Date: June 1, 1987
Creator: Dresner, L.
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Partner: UNT Libraries Government Documents Department
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Combustion of ultrafine coal/water mixtures and their application in gas turbines: Final report

Description: The feasibility of using coal-water fuels (CWF) in gas turbine combustors has been demonstrated in recent pilot plant experiments. The demands of burning coal-water fuels with high flame stability, complete combustion, low NO/sub x/ emission and a resulting fly ash particle size that will not erode turbine blades represent a significant challenge to combustion scientists and engineers. The satisfactory solution of these problems requires that the variation of the structure of CWF flames, i.e., … more
Date: October 1, 1987
Creator: Toqan, M.A.; Srinivasachar, S.; Staudt, J.; Varela, F. & Beer, J.M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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COMMIX analysis of the Sodium Heated Helical Coil Steam Generator

Description: This paper describes the COMMIX-HCSG computer program and compares predictions to data obtained from performance tests on a 76 MWt Helical Coil Steam Generator (HCSG) test unit. COMMIX-HCSG is a multi-dimensional thermal/hydraulic code that models both steady state and transient operation of an HCSG. The code solves a system of Navier-Stokes continuum equations that have been modified with a combination of volume and directional surface porosities and distributed resistances. This formulation p… more
Date: January 1, 1987
Creator: Kakarala, C. R.; Burge, S. W. & Sha, W. T.
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Partner: UNT Libraries Government Documents Department
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The relation of solar wind structure to hydromagnetic discontinuities

Description: High resolution ISEE-3 data have been used to examine the relative abundances of tangential (TD) vs rotational (RD) discontinuities in different types of solar wind flow. Three types of flow were examined; flow from coronal holes, sector boundary flow and transient flow. It has been found that coronal hole flow has substantially more discontinuities and a greater ratio of RD's to TD's than do the other types of flow. Discontinuities are least frequent in transient flows characterized by bidirec… more
Date: January 1, 1987
Creator: Alexander, C. J.; Neugebauer, M.; Smith, E. J. & Bame, S. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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PIC (Particle-in-Cell) and its progeny

Description: The Particle-in-Cell (PIC) method was developed to solve numerically for the strongly contorting dynamics of several materials in two or three space dimensions. Related numerical techniques with Lagrangian marker particles are also discussed in this brief survey. An extensive bibliography lists many of the earlier publications describing these techniques.
Date: January 1, 1987
Creator: Harlow, F. H.
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Partner: UNT Libraries Government Documents Department
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Three-dimensional computer modeling of particulate flow around dust monitors

Description: SOLA-DM is a three-dimensional finite-difference computer code designed to model the dynamics of an incompressible fluid and the transport of discrete particulate material around obstacles impervious to flow. The numerical methods used in this code are described. SOLA-DM was used to predict the particle flux sampled by the 10-mm Dorr-Oliver Cyclone and MINIRAM dust monitors. Various geometric and dynamic variations of monitor and airflow combinations were tested. The code predictions are shown … more
Date: January 1, 1987
Creator: Nichols, B. D. & Gregory, W. S.
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Partner: UNT Libraries Government Documents Department
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Comparisons of power transfer functions and flow transfer functions

Description: Transfer functions may be used to calculate component feedbacks or temperature increments by convolution of the transfer function with the appropriate fractional change in system-quantity. Power-change transfer functions have been reported. The corresponding flow transfer functions for this case, and comparison with the power transfer functions, are reported here. Results of feedback simulation of ramped flow transients using flow transfer functions are also described.
Date: November 15, 1987
Creator: Grimm, K. N. & Meneghetti, D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Numerical models for high beta magnetohydrodynamic flow

Description: The fundamentals of numerical magnetohydrodynamics for highly conducting, high-beta plasmas are outlined. The discussions emphasize the physical properties of the flow, and how elementary concepts in numerical analysis can be applied to the construction of finite difference approximations that capture these features. The linear and nonlinear stability of explicit and implicit differencing in time is examined, the origin and effect of numerical diffusion in the calculation of convective transpor… more
Date: January 1, 1987
Creator: Brackbill, J.U.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Three-dimensional, Free-Lagrange hydrodynamics

Description: This paper describes the algorithms that make up a 3-D version of the Free-Lagrange Method. The basic method involves the explicit integration of the fluid flow equations over control volumes formed by Voronoi cells. A Voronoi cell is an arbitrary, convex polyhedron that has plane polygon faces. The ''nearest'' neighbors of any given mass point are identified by noting the mass point that lies on the opposite side of a given Voronoi face. The nearest neighbors of a mass point are allowed to cha… more
Date: January 1, 1987
Creator: Trease, H.
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Partner: UNT Libraries Government Documents Department
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Inferences drawn from shock-enhanced turbulent mixing analyses

Description: This discussion concerns analyses of physical shock-tube and shock-boundary layer interaction experiments, supplemented by computations. The basic issue is that of evaluating the influence of reflected shock waves on enhancing the balance of turbulent kinetic energy and resultant turbulent materials mixing during implosion and shock reflection intervals. Increases in random velocity amplitudes of a factor of 5 or greater implying turbulent kinetic energy increases of a factor of 12 or more have… more
Date: October 16, 1987
Creator: Buckingham, A.C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Statistical theory of turbulent incompressible multimaterial flow

Description: Interpenetrating motion of incompressible materials is considered. ''Turbulence'' is defined as any deviation from the mean motion. Accordingly a nominally stationary fluid will exhibit turbulent fluctuations due to a single, slowly moving sphere. Mean conservation equations for interpenetrating materials in arbitrary proportions are derived using an ensemble averaging procedure, beginning with the exact equations of motion. The result is a set of conservation equations for the mean mass, momen… more
Date: October 1, 1987
Creator: Kashiwa, B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Point vortex dynamics: Recent results and open problems

Description: The concept of point vortex motion, a classical model in the theory of two-dimensional, incompressible fluid mechanics, was introduced by Helmholtz in 1858. Exploration of the solutions to these equations has made fitful progress since that time as the point vortex model has been brought to bear on various physical situations: atomic structure, large-scale weather patterns, ''vortex street'' wakes, vortex lattices in superfluids and superconductors, etc. The point vortex equations also provide … more
Date: January 1, 1987
Creator: Aref, H.; Kadtke, J. B.; Zawadzki, I.; Campbell, L. J. & Eckhardt, B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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In-vessel flow characterization under severe accident conditions

Description: The purpose of this study is to provide a parametric framework for characterization of flow and heat transfer regimes and their associated phenomenological uncertainties following severe accidents using a two dimensional, heterogenous, porous media formulation. This approach extends the understanding of buoyancy-induced flow characteristics in the uncovered region of the reactor core and the upper plenum of a PWR vessel. The results of this study can be used to augment the boil-off steam flow i… more
Date: January 1, 1987
Creator: Nourbakhsh, H.P.; Kim, S.B. & Khatib-Rahbar, M.
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Partner: UNT Libraries Government Documents Department
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Two-Phase Flow in Geothermal Systems

Description: The overall object was to establish a full experimental correlation between flashing flows of water-steam in actual geothermal wells and flashing flows of refrigerant-114 (R-114) in the Brown University/DOE Two-Phase Flow Facility. Our experiments show that the similarity theory developed in our laboratory during previous phases of this research project can be used to predict accurately the pressure gradient in the two-phase region of a flowing geothermal well using laboratory measurements on R… more
Date: August 1, 1987
Creator: Maeder, P. F. & Kestin, J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Numerical simulation of flow in Brush Creek Valley, Colorado

Description: In this paper, we present some results from our three-dimensional, non-hydrostatic, finite element model applied to simulations of flow in Brush Creek Valley. These simulations are not intended to reproduce any particular experiment, but rather are to evaluate the qualitative performance of the model, to explore the major difficulties involved, and to begin sensitivity studies of the flows of interest. 2 refs., 11 figs.
Date: June 1, 1987
Creator: Leone, J. M. Jr. & Lee, R. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A void distribution model-flashing flow

Description: A new model for flashing flow based on wall nucleations is proposed here and the model predictions are compared with some experimental data. In order to calculate the bubble number density, the bubble number transport equation with a distributed source from the wall nucleation sites was used. Thus it was possible to avoid the usual assumption of a constant bubble number density. Comparisons of the model with the data shows that the model based on the nucleation site density correlation appears … more
Date: January 1, 1987
Creator: Riznic, J.; Ishii, M. & Afgan, N.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Theoretical and empirical study of single-substance, upward two-phase flow in a constant-diameter adiabatic pipe

Description: A Scheme is developed to describe the upward flow of a two-phase mixture of a single substance in a vertical adiabatic constant area pipe. The scheme is based on dividing the mixture into a homogeneous core surrounded by a liquid film. This core may be a mixture of bubbles in a contiguous liquid phase, or a mixture of droplets in a contiguous vapor phase. Emphasis is placed upon the latter case since the range of experimental measurements of pressure, temperature, and void fraction collected in… more
Date: May 1, 1987
Creator: Laoulache, R. N.; Maeder, P. F. & DiPippo, R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Node-based network analysis and its application to mine ventilation

Description: A numerical procedure to model flow networks using a node-based approach is discussed, and the analysis encompasses both steady-state and transient solutions. A family of computer codes has been developed using the node-based approach. This technique is illustrated by applying two of the computer codes to mine ventilation networks.
Date: January 1, 1987
Creator: Gregory, W. S.; Nichols, B. D. & Idzorek, R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Birch's law and the properties of high temperature fluid metals

Description: By comparing acoustic velocities in fluid metals over a very wide range of densities we have established Birch's Law as an approximate representation over the entire liquid range. For a given liquid metal the acoustic velocity is close to linear in density, with a slope determined by the atomic weight. The measurements include isobaric expansion to less than half normal density, ultrasonics on molten metals at 1 atmosphere, and shock-melted metals to greater than twice normal density. We also f… more
Date: January 1, 1987
Creator: Shaner, J.W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Stratabound pathways of preferred groundwater flow: An example from the Copper Ridge Dolomite in East Tennessee

Description: The Copper Ridge Dolomite of the Upper Cambrian Knox Group underlies a site at Oak Ridge, Tennessee under consideration by the Department of Energy (DOE) for a below ground waste disposal facility. The Copper Ridge was studied for DOE to understand the influence of lithology on deep groundwater flow. Three facies types are distinguished which comprise laterally continuous, 1 to 4 m thick rock units interpreted to represent upward-shallowing depositional cycles having an apparently significant e… more
Date: July 14, 1987
Creator: Lee, R. & Ketelle, D.
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Partner: UNT Libraries Government Documents Department
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A method for treating hourglass patterns

Description: Hourglassing is a problem frequently encountered in numerical simulations of fluid and solid dynamics. The problem arises because certain volume-preserving distortions of cell shape produce no restoring forces. The result is an unrestricted drifting mode in the velocity field that leads to severe distortions of the computational mesh. These distortions cause large errors in the numerical approximations of the equations of motion. The drift may also allow adjacent vertices to get very close to e… more
Date: January 1, 1987
Creator: Margolin, L. G. & Pyun, J. J.
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Partner: UNT Libraries Government Documents Department
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An analytic model for flow reversal in divertor plasmas

Description: An analytic model is developed and used to study the phenomenon of flow reversal which is observed in two-dimensional simulations of divertor plasmas. The effect is shown to be caused by the radial spread of neutral particles emitted from the divertor target which can lead to a strong peaking of the ionization source at certain radial locations. The results indicate that flow reversal over a portion of the width of the scrape-off layer is inevitable in high recycling conditions. Implications fo… more
Date: April 1, 1987
Creator: Cooke, P.I.H. & Prinja, A.K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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CAVEAT calculations of shock interactions

Description: CAVEAT is a computer code for calculating the time-varying fluid dynamics of several adjacent materials in two or three space dimensions. Using an extended Godunov technique and adaptive meshing, the code allows for large slippage at material interfaces. To exhibit the capability for calculating strong distortions we have performed a variety of calculations describing the interaction of shocks with rigid wedges, cylinders, and spheres and deformable cylindrical, spherical, and conical shells in… more
Date: June 1, 1987
Creator: Sandoval, D.L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Radioactive Waste Burial Grounds. Environmental Information Document

Description: This document provides environmental information on postulated closure options for the Radioactive Waste Burial Grounds at the Savannah River Plant and was developed as background technical documentation for the Department of Energy`s proposed Environmental Impact Statement (EIS) on waste management activities for groundwater protection at the plant. The results of groundwater and atmospheric pathway analyses, accident analysis, and other environmental assessments discussed in this document are… more
Date: March 1, 1987
Creator: Jaegge, W. J.; Kolb, N. L.; Looney, B. B.; Marine, I. W.; Towler, O. A. & Cook, J. R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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