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PRESSURE EQUALIZATION BY FLUID EXCHANGE BETWEEN PARALLEL FLOW CHANNELS

Description: Hydraulic and deflection analyses of the unequal flow passages in the HFIR control region revealed excessive pressure differentials. A proposal to drill connecting holes between the flow passages initiated an experimental program for investigating the effectiveness crossflow on pressure equalization. Empirical constants for an analytical model and experimental design data on reduction of pressure differentials between channels were obtained. It was determined that crossflow between channels would satisfactorily reduce the pressure differentials. (auth)
Date: April 1, 1963
Creator: Chapman, T.G. & Stevens, P.N.
Partner: UNT Libraries Government Documents Department

The Interfacial-Area-Based Relative Permeability Function

Description: CH2M Hill Plateau Remediation Company (CHPRC) requested the services of the Pacific Northwest National Laboratory (PNNL) to provide technical support for the Remediation Decision Support (RDS) activity within the Soil & Groundwater Remediation Project. A portion of the support provided in FY2009, was to extend the soil unsaturated hydraulic conductivity using an alternative approach. This alternative approach incorporates the Brooks and Corey (1964), van Genuchten (1980), and a modified van Genuchten water-retention models into the interfacial-area-based relative permeability model presented by Embid (1997). The general performance of the incorporated models is shown using typical hydraulic parameters. The relative permeability models for the wetting phase were further examined using data from literature. Results indicate that the interfacial-area-based model can describe the relative permeability of the wetting phase reasonably well.
Date: September 25, 2009
Creator: Zhang, Z. F. & Khaleel, Raziuddin
Partner: UNT Libraries Government Documents Department

PRELIMINARY INVESTIGATIONS INTO THE PREPARATION OF EXTRUDED GRAPHITE

Description: Graphite was prepared by means of hydraulic extrusion, with densities as high as 1.90 gm/cc, in rods of up to 9/4-in. in diam. Densities higher than 1.90 gm/cc can be obtained by impregnating the graphite. It may be possible, by properly controlling the particle size distribution in the feed material, to achieve higher densities without impregnation. Variables studied included die temperature, mixing technique, binder material, baking procedures, some lubricants and additives, and preliminary work on the investigation of the effect of particle size. (auth)
Date: March 13, 1958
Creator: Gibson, W.B.
Partner: UNT Libraries Government Documents Department

SIR FREEZE SEAL TEST II

Description: Two arrangements of internal components of a freeze seal model were tested in order to determine the hydraulic characteristics. The internal configuration employing cylindrical knitted mesh packings in the connecting pipes proved the most suitable for the Na servicing freeze seal, because these packings are more easily fabricated. (auth)
Date: May 25, 1954
Creator: Jacoby, R.G. & Benson, P.A.
Partner: UNT Libraries Government Documents Department

90-Ton Triple Cylinder Jack Design

Description: The three D-Zero cryostats (2 EC and 1 CC) will rest on three carriages which in turn ride on a set of hardened ways in the center beam. A pair of Tychoway rollers will be fitted to each of the four corners of the three carriages to provide the rolling support. In the final design, the two EC cryostats will be able to roll out and away from the CC cryostat in order to provide access to the space between each cryostat for maintenance and repairs. The cryostat will be frequently accessed, about once a month. during a collider run. The heaviest cryostat weighs about 360 tons. The large roller weight in one position for such a long period of time, created a concern about the rollers dimpling the hardened ways or even suffering permanent deformations themselves. There is also the possibility that the vertical position of the cryostat will need to be adjusted to align it with the beam line or that the carriage and cryostat will have to be lifted to remove and service the rollers. A device or system was needed to (1) relieve the weight of the cryostats from the rollers and the hardened ways, and (2) minimally adjust the vertical position of the cryostats, if necessary, and/or service the rollers. Compact hydraulic jacks seemed to be the answer. The first and foremost criteria was capacity. It was desired that the jacks be rated to twice the actual load. A jack is to be placed beside each roller, giving a total of eight per cryostat. The load per jack for a 360 ton cryostat would then be 45 tons, leaving 90 tons as the required capacity. The second and equally important criteria to be met was size. After installation of the Tychoway rollers. room to mount ...
Date: September 26, 1988
Creator: Jaques, Al
Partner: UNT Libraries Government Documents Department

CC-EC Transporter Analysis

Description: The following calculations were used to develop a structure required to transport completed calorimeters (CC-EC) from the assembly area to a staging point for installation onto center beam. The transporter is equipped with four (4) 200 ton hydraulic cylinders and four (4) 200 ton capacity Hillman Rollers. The components are used for the lifting and moving of calorimeters. R. Wands is doing the Ansys analysis based on 2 conditions: (1) Statically loaded on the transporter support corner; and (2) Loaded on 3 Hilman's with 1 Hilman removed.
Date: December 7, 1987
Creator: Stredde, H.J.
Partner: UNT Libraries Government Documents Department

Load on Trough Bellows Following an Argon Spill

Description: In the case of a gross argon spill from the DO detector, the liquid argon is caught in three plenums. These plenums are to be connected by bellows to make a horizontal trough open at one end for removing the argon. The design of these bellows is dependent on the maximum argon load they must carry. Bellows to connect the three argon-catching plenums in the DO detector must be able to carry at least 92 lbs of argon when closed and 231 lbs when open, plus the load due to argon in the convolutions. Examples of such loads and the method for their calculations are contained in the Discussion. It should be noted that a set of assumptions was used in these calculations. First, we considered a uniform channel and uniform flow. Second, we used a value for Manning's n meant for a similar, but not exactly the same, case. Finally, we were forced to define an average depth, d, to be used to state the hydraulic radius, R, and area of flow, A. These facts may warrant consideration in future calculations.
Date: July 12, 1988
Creator: Chess, K.
Partner: UNT Libraries Government Documents Department

Estimation of fracture flow parameters through numerical analysis of hydromechanical pressure pulses

Description: The flow parameters of a natural fracture were estimated by modeling in situ pressure pulses. The pulses were generated in two horizontal boreholes spaced 1 m apart vertically and intersecting a near-vertical highly permeable fracture located within a shallow fractured carbonate reservoir. Fracture hydromechanical response was monitored using specialized fiber-optic borehole equipment that could simultaneously measure fluid pressure and fracture displacements. Measurements indicated a significant time lag between the pressure peak at the injection point and the one at the second measuring point, located 1 m away. The pressure pulse dilated and contracted the fracture. Field data were analyzed through hydraulic and coupled hydromechanical simulations using different governing flow laws. In matching the time lag between the pressure peaks at the two measuring points, our hydraulic models indicated that (1) flow was channeled in the fracture, (2) the hydraulic conductivity tensor was highly anisotropic, and (3) the radius of pulse influence was asymmetric, in that the pulse travelled faster vertically than horizontally. Moreover, our parametric study demonstrated that the fluid pressure diffusion through the fracture was quite sensitive to the spacing and orientation of channels, hydraulic aperture, storativity and hydraulic conductivity. Comparison between hydraulic and hydromechanical models showed that the deformation significantly affected fracture permeability and storativity, and consequently, the fluid pressure propagation, suggesting that the simultaneous measurements of pressure and mechanical displacement signals could substantially improve the interpretation of pulse tests during reservoir characterization.
Date: March 16, 2008
Creator: Cappa, F.; Guglielmi, Y.; Rutqvist, J.; Tsang, C.-F. & Thoraval, A.
Partner: UNT Libraries Government Documents Department

Model development and calibration for the coupled thermal, hydraulic and mechanical phenomena of the bentonite

Description: In Task A of the international DECOVALEX-THMC project, five research teams study the influence of thermal-hydro-mechanical (THM) coupling on the safety of a hypothetical geological repository for spent fuel. In order to improve the analyses, the teams calibrated their bentonite models with results from laboratory experiments, including swelling pressure tests, water uptake tests, thermally gradient tests, and the CEA mock-up THM experiment. This paper describes the mathematical models used by the teams, and compares the results of their calibrations with the experimental data.
Date: February 1, 2009
Creator: Chijimatsu, M.; Borgesson, L.; Fujita, T.; Jussila, P.; Nguyen, S.; Rutqvist, J. et al.
Partner: UNT Libraries Government Documents Department

Modeling basin- and plume-scale processes of CO2 storage for full-scale deployment

Description: Integrated modeling of basin- and plume-scale processes induced by full-scale deployment of CO{sub 2} storage was applied to the Mt. Simon Aquifer in the Illinois Basin. A three-dimensional mesh was generated with local refinement around 20 injection sites, with approximately 30 km spacing. A total annual injection rate of 100 Mt CO{sub 2} over 50 years was used. The CO{sub 2}-brine flow at the plume scale and the single-phase flow at the basin scale were simulated. Simulation results show the overall shape of a CO{sub 2} plume consisting of a typical gravity-override subplume in the bottom injection zone of high injectivity and a pyramid-shaped subplume in the overlying multilayered Mt. Simon, indicating the important role of a secondary seal with relatively low-permeability and high-entry capillary pressure. The secondary-seal effect is manifested by retarded upward CO{sub 2} migration as a result of multiple secondary seals, coupled with lateral preferential CO{sub 2} viscous fingering through high-permeability layers. The plume width varies from 9.0 to 13.5 km at 200 years, indicating the slow CO{sub 2} migration and no plume interference between storage sites. On the basin scale, pressure perturbations propagate quickly away from injection centers, interfere after less than 1 year, and eventually reach basin margins. The simulated pressure buildup of 35 bar in the injection area is not expected to affect caprock geomechanical integrity. Moderate pressure buildup is observed in Mt. Simon in northern Illinois. However, its impact on groundwater resources is less than the hydraulic drawdown induced by long-term extensive pumping from overlying freshwater aquifers.
Date: August 15, 2009
Creator: Zhou, Q.; Birkholzer, J.T.; Mehnert, E.; Lin, Y.-F. & Zhang, K.
Partner: UNT Libraries Government Documents Department

On the Relationship between Stress and Elastic Strain for Porous and Fractured Rock

Description: Modeling the mechanical deformations of porous and fractured rocks requires a stress-strain relationship. Experience with inherently heterogeneous earth materials suggests that different varieties of Hook's law should be applied within regions of the rock having significantly different stress-strain behavior, e.g., such as solid phase and various void geometries. We apply this idea by dividing a rock body conceptually into two distinct parts. The natural strain (volume change divided by rock volume at the current stress state), rather than the engineering strain (volume change divided by the unstressed rock volume), should be used in Hooke's law for accurate modeling of the elastic deformation of that part of the pore volume subject to a relatively large degree of relative deformation (i.e., cracks or fractures). This approach permits the derivation of constitutive relations between stress and a variety of mechanical and/or hydraulic rock properties. We show that the theoretical predictions of this method are generally consistent with empirical expressions (from field data) and also laboratory rock experimental data.
Date: February 25, 2008
Creator: Liu, Hui-Hai; Rutqvist, Jonny & Berryman, James G.
Partner: UNT Libraries Government Documents Department

Optimality and Conductivity for Water Flow: From Landscapes, to Unsaturated Soils, to Plant Leaves

Description: Optimality principles have been widely used in many areas. Based on an optimality principle that any flow field will tend toward a minimum in the energy dissipation rate, this work shows that there exists a unified form of conductivity relationship for three different flow systems: landscapes, unsaturated soils and plant leaves. The conductivity, the ratio of water flux to energy gradient, is a power function of water flux although the power value is system dependent. This relationship indicates that to minimize energy dissipation rate for a whole system, water flow has a small resistance (or a large conductivity) at a location of large water flux. Empirical evidence supports validity of the relationship for landscape and unsaturated soils (under gravity dominated conditions). Numerical simulation results also show that the relationship can capture the key features of hydraulic structure for a plant leaf, although more studies are needed to further confirm its validity. Especially, it is of interest that according to this relationship, hydraulic conductivity for gravity-dominated unsaturated flow, unlike that defined in the classic theories, depends on not only capillary pressure (or saturation), but also the water flux. Use of the optimality principle allows for determining useful results that are applicable to a broad range of areas involving highly non-linear processes and may not be possible to obtain from classic theories describing water flow processes.
Date: February 23, 2012
Creator: Liu, H.H.
Partner: UNT Libraries Government Documents Department

Hydraulic properties of adsorbed water films in unsaturated porous media

Description: Adsorbed water films strongly influence residual water saturations and hydraulic conductivities in porous media at low saturations. Hydraulic properties of adsorbed water films in unsaturated porous media were investigated through combining Langmuir's film model with scaling analysis, without use of any adjustable parameters. Diffuse double layer influences are predicted to be important through the strong dependence of adsorbed water film thickness (f) on matric potential ({Psi}) and ion charge (z). Film thickness, film velocity, and unsaturated hydraulic conductivity are predicted to vary with z{sup -1}, z{sup -2}, and z{sup -3}, respectively. In monodisperse granular media, the characteristic grain size ({lambda}) controls film hydraulics through {lambda}{sup -1} scaling of (1) the perimeter length per unit cross sectional area over which films occur, (2) the critical matric potential ({Psi}{sub c}) below which films control flow, and (3) the magnitude of the unsaturated hydraulic conductivity when {Psi} < {Psi}{sub c}. While it is recognized that finer textured sediments have higher unsaturated hydraulic conductivities than coarser sands at intermediate {Psi}, the {lambda}{sup -1} scaling of hydraulic conductivity predicted here extends this understanding to very low saturations where all pores are drained. Extremely low unsaturated hydraulic conductivities are predicted under adsorbed film-controlled conditions (generally < 0.1 mm y{sup -1}). On flat surfaces, the film hydraulic diffusivity is shown to be constant (invariant with respect to {Psi}).
Date: March 1, 2009
Creator: Tokunaga, Tetsu K.
Partner: UNT Libraries Government Documents Department

Continuous time random walk analysis of solute transport in fractured porous media

Description: The objective of this work is to discuss solute transport phenomena in fractured porous media, where the macroscopic transport of contaminants in the highly permeable interconnected fractures can be strongly affected by solute exchange with the porous rock matrix. We are interested in a wide range of rock types, with matrix hydraulic conductivities varying from almost impermeable (e.g., granites) to somewhat permeable (e.g., porous sandstones). In the first case, molecular diffusion is the only transport process causing the transfer of contaminants between the fractures and the matrix blocks. In the second case, additional solute transfer occurs as a result of a combination of advective and dispersive transport mechanisms, with considerable impact on the macroscopic transport behavior. We start our study by conducting numerical tracer experiments employing a discrete (microscopic) representation of fractures and matrix. Using the discrete simulations as a surrogate for the 'correct' transport behavior, we then evaluate the accuracy of macroscopic (continuum) approaches in comparison with the discrete results. However, instead of using dual-continuum models, which are quite often used to account for this type of heterogeneity, we develop a macroscopic model based on the Continuous Time Random Walk (CTRW) framework, which characterizes the interaction between the fractured and porous rock domains by using a probability distribution function of residence times. A parametric study of how CTRW parameters evolve is presented, describing transport as a function of the hydraulic conductivity ratio between fractured and porous domains.
Date: June 1, 2008
Creator: Cortis, Andrea; Cortis, Andrea & Birkholzer, Jens
Partner: UNT Libraries Government Documents Department

The Migration and Entrapment of DNAPLs in Physically and Chemically Heterogeneous Porous Media

Description: This document summarizes EMSP funded research designed to improve our understanding of and ability to simulate the influence of subsurface chemical heterogeneities on DNAPL flow and entrapment in the saturated zone. Specific project objectives include: (i) the quantification of DNAPL interfacial and hydraulic properties; (ii) development and assessment of constitutive hydraulic property and continuum based multiphase flow models; (iii) exploration of DNAPL migration and entrapment in heterogeneous systems at larger scales; and (iv) development of innovative remediation schemes.
Date: June 1, 2000
Creator: Abriola, Linda M. & Demond, Avery H.
Partner: UNT Libraries Government Documents Department

Understanding the impact of upscaling THM processes on performance assessment

Description: The major objective of Benchmark Test 2 (BMT2) is to quantitatively examine the reliability of estimates of repository host rock performance, using large-scale performance assessment (PA) models that are developed by upscaling small-scale parameters and processes. These small-scale properties and processes can be investigated based on either discrete-fracture-network (DFN) models or heterogeneous-porous-medium (HPM) models. While most research teams use DFN, we employ fractal-based HPM for upscaling purposes. Comparison of results based on fundamentally different approaches is useful for evaluating and bounding the uncertainties in estimating repository host rock performance. HPM has both advantages and limitations when compared with DFN. DFM is conceptually more appealing because it explicitly describes fractures and the flow and transport processes that occur within them. However, HPM is more consistent with approaches used to derive field measurements of hydraulic properties (such as permeability). These properties are generally determined based on assumptions related to the continuum approach. HPM is also more straightforward in describing spatial-correlation structures of measured hydraulic properties. For example, potential flow features in the Borrowdale Volcanic Group (BVG) were found to show marked spatial clustering (Nirex, 1997), which is expected to result in a long range correlation in measured permeability distributions. This important behavior may not be captured with conventional DFNs, in which random distribution (or similar distributions) of individual fractures is assumed. The usefulness of HPM will be partially demonstrated in this report by a satisfactory description of the short interval testing data using Levy-stable fractals. (Recently, Jackson et al. (2000) also showed that equivalent HPMs could approximately describe flow processes within subgrid fracture networks.) We use Monte Carlo simulations to determine flow and transport parameters at different scales. Since we have used a fractal-based approach supported by field measurements, effective properties will be scale-dependent. Effects of mechanical processes on flow and transport ...
Date: June 10, 2002
Creator: Liu, H. H.; Zhou, Q.; Rutqvist, J. & Bodvarsson, G. S.
Partner: UNT Libraries Government Documents Department

Enhanced geothermal systems (EGS) using CO2 as working fluid - Anovelapproach for generating renewable energy with simultaneoussequestration of carbon

Description: Responding to the need to reduce atmospheric emissions of carbon dioxide, Donald Brown (2000) proposed a novel enhanced geothermal systems (EGS) concept that would use CO{sub 2} instead of water as heat transmission fluid, and would achieve geologic sequestration of CO{sub 2} as an ancillary benefit. Following up on his suggestion, we have evaluated thermophysical properties and performed numerical simulations to explore the fluid dynamics and heat transfer issues in an engineered geothermal reservoir that would be operated with CO{sub 2}. We find that CO{sub 2} is superior to water in its ability to mine heat from hot fractured rock. CO{sub 2} also has certain advantages with respect to wellbore hydraulics, where larger compressibility and expansivity as compared to water would increase buoyancy forces and would reduce the parasitic power consumption of the fluid circulation system. While the thermal and hydraulic aspects of a CO{sub 2}-EGS system look promising, major uncertainties remain with regard to chemical interactions between fluids and rocks. An EGS system running on CO{sub 2} has sufficiently attractive features to warrant further investigation.
Date: June 7, 2006
Creator: Pruess, Karsten
Partner: UNT Libraries Government Documents Department

Fracture Detection: Interpretation of Well Logs to Select Packer Seats and Locate Injection Intervals

Description: A wireline and mud logging program has been conducted in conjunction with redrilling operations in well EE-3 at the Fenton Hill Hot Dry Rock (HDR) site near Valles Caldera, New Mexico. The trajectory for the new bore, EE-3A, penetrated a fractured zone stimulated from adjacent well EE-2 and thereby established hydraulic communication. To test and stimulate selected zones in EE-3A inflatable open hole packers designed for high temperature service were used. Proper identification and selection of packer seats was crucial to the success of the project. The logging program successfully identified five competent packer seats in six attempts. Wireline temperature, caliper, sonic televiewer and natural gamma ray logs were used in conjunction with mud logs, drill cuttings and drilling parameter data to locate fractures, out-of-gage hole, temperature anomalies and mineralized zones which were avoided in selection of the packer seats.
Date: January 21, 1986
Creator: Dreesen, D. S.; Burns, K. L.; Chavez, P.; Dash, Z. V.; Kelkar, S.; Kolar, J. et al.
Partner: UNT Libraries Government Documents Department

MH Test Filler Force Limitations

Description: The OH modules for the DO end calorimeter are being tested by supporting a load to simulate the MH, IH, and EM modules. This test structure, the MH filler, is inserted into the previously assembled OH modules, and then loaded with hydraulic jacks. The maximum test load applied by the jacks is 78,600 lb, which is via the two downstream jacks at 130% of the nominal load. Bill Cooper's memo of 9/10/90 is include as appendix C. This note presents calculations for the AISC maximum allowable stresses/loads of the various parts of the testing assembly. Furthermore, calculations show that the actual test load is less than the AISC allowable.
Date: October 2, 1990
Creator: Primdahl, K. A.
Partner: UNT Libraries Government Documents Department

MODELING STRATEGIES TO COMPUTE NATURAL CIRCULATION USING CFD IN A VHTR AFTER A LOFA

Description: A prismatic gas-cooled very high temperature reactor (VHTR) is being developed under the next generation nuclear plant program (NGNP) of the U.S. Department of Energy, Office of Nuclear Energy. In the design of the prismatic VHTR, hexagonal shaped graphite blocks are drilled to allow insertion of fuel pins, made of compacted TRISO fuel particles, and coolant channels for the helium coolant. One of the concerns for the reactor design is the effects of a loss of flow accident (LOFA) where the coolant circulators are lost for some reason, causing a loss of forced coolant flow through the core. In such an event, it is desired to know what happens to the (reduced) heat still being generated in the core and if it represents a problem for the fuel compacts, the graphite core or the reactor vessel (RV) walls. One of the mechanisms for the transport of heat out of the core is by the natural circulation of the coolant, which is still present. That is, how much heat may be transported by natural circulation through the core and upwards to the top of the upper plenum? It is beyond current capability for a computational fluid dynamic (CFD) analysis to perform a calculation on the whole RV with a sufficiently refined mesh to examine the full potential of natural circulation in the vessel. The present paper reports the investigation of several strategies to model the flow and heat transfer in the RV. It is found that it is necessary to employ representative geometries of the core to estimate the heat transfer. However, by taking advantage of global and local symmetries, a detailed estimate of the strength of the resulting natural circulation and the level of heat transfer to the top of the upper plenum is obtained.
Date: November 1, 2012
Creator: Tung, Yu-Hsin; Johnson, Richard W.; Chieng, Ching-Chang & Ferng, Yuh-Ming
Partner: UNT Libraries Government Documents Department

PERFORMANCE OF HNPF PROTOTYPE FREE-SURFACE SODIUM PUMP

Description: A free-surface centrifugal pump, incorporating a hydraulic bearing running in sodium, was operated at the conditions required for service in the Hallam Power Reactor. After difficulties arising from inadequate shaft clearances were alleviated, the pump performed properly at a flow rate of 7200 gpm of 945 gas-cooled F sodium at 150-ft head. Results Hallam plant. (auth)
Date: June 30, 1960
Creator: Atz, R. W.
Partner: UNT Libraries Government Documents Department

FRACSL CODE DEVELOPMENT AND CORRELATION OF EAST MESA TEST RESULTS

Description: The FRACSL flow and transport code is under development as part of an effort to improve reservoir characterization techniques. The present version simulates a two-dimensional, isothermal reservoir composed of a global fracture network imbedded in a porous media. FRACSL simulates the hydraulic response of a reservoir to injection or backflow. The code simulates the movement of injected tracers within the reservoir by adding advective and random dispersive motions of discrete particles. FRACSL has been benchmarked against theoretical flow and transport responses in simple systems. It has been used to simulate a benchscale physical model and to correlate flow and dispersion data from the East Mesa Hydrothermal Injection Test Program. Correlation of East Mesa data has provided an estimate of an anisotropic hydraulic conductivity, a natural drift in the reservoir, and dispersivity.
Date: January 22, 1985
Creator: Clemo, T.M.
Partner: UNT Libraries Government Documents Department