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Design of a high-power density Ljungstrom turbine using potassium as a working fluid

Description: The ability to generate large quantities of high-quality power in space will be necessary to meet the needs of many proposed future space programs. The Pacific Northwest Laboratory is studying an advanced multi-megawatt space power system employing a liquid metal Rankine power cycle. This paper examines more closely one component of the system, the power turbine. The turbine design selected for this system is a counter-rotating radial-outflow machine developed in the early twentieth century by two brothers, Fredrik and Birger Ljungstroem turbine was selected because it provides a compact, high-power-density turbine with balanced rotational inertia and is tolerant of moisture in the working fluid. In commercial operation, Ljungstroem turbines have demonstrated excellent rapid start capabilities and good overall efficiency. Moreover, the disadvantages that have hindered its use in conventional power plants are tied to the steam's very large change in specific volume. These disadvantages are circumvented in a machine using potassium for a working fluid. A preliminary design study indicates that high-power turbines, using potassium as a working fluid, are feasible for the Ljungstroem turbine, and that Ljungstroem turbines of 200 MW and greater could easily fit into the cargo bay of the space shuttle. 10 refs., 5 figs. 3 tabs.
Date: April 1, 1986
Creator: Coomes, E.P.; Dodge, R.E.; Wilson, D.G. & McCabe, S.J.
Partner: UNT Libraries Government Documents Department

Pressurized fluidized-bed combustion technology exchange workshop

Description: The pressurized fluidized-bed combustion technology exchange workshop was held June 5 and 6, 1979, at The Meadowlands Hilton Hotel, Secaucus, New Jersey. Eleven papers have been entered individually into EDB and ERA. The papers include reviews of the US DOE and EPRI programs in this area and papers by Swedish, West German, British and American organizations. The British papers concern the joint program of the USA, UK and FRG at Leatherhead. The key factor in several papers is the use of fluidized bed combustors, gas turbines, and steam turbines in combined-cycle power plants. One paper examines several combined-cycle alternatives. (LTN)
Date: April 1, 1980
Creator: ,
Partner: UNT Libraries Government Documents Department

Ultra-Supercritical Steam Corrosion

Description: Efficiency increases in fossil energy boilers and steam turbines are being achieved by increasing the temperature and pressure at the turbine inlets well beyond the critical point of water. To allow these increases, advanced materials are needed that are able to withstand the higher temperatures and pressures in terms of strength, creep, and oxidation resistance. As part of a larger collaborative effort, the Albany Research Center (ARC) is examining the steam-side oxidation behavior for ultrasupercritical (USC) steam turbine applications. Initial tests are being done on six alloys identified as candidates for USC steam boiler applications: ferritic alloy SAVE12, austenitic alloy Super 304H, the high Cr-high Ni alloy HR6W, and the nickel-base superalloys Inconel 617, Haynes 230, and Inconel 740. Each of these alloys has very high strength for its alloy type. Three types of experiments are planned: cyclic oxidation in air plus steam at atmospheric pressure, thermogravimetric ana lysis (TGA) in steam at atmospheric pressure, and exposure tests in supercritical steam up to 650 C (1202 F) and 34.5 MPa (5000 psi). The atmospheric pressure tests, combined with supercritical exposures at 13.8, 20.7, 24.6, and 34.5 MPa (2000, 3000, 4000, and 5000 psi) should allow the determination of the effect of pressure on the oxidation process.
Date: April 22, 2003
Creator: Holcomb, G. R.; Alman, D. E.; Bullard, S. B.; Covino, B. S., Jr.; Cramer, S. D. & Ziomek-Moroz, M.
Partner: UNT Libraries Government Documents Department

Biaxial loading and shallow-flaw effects on crack-tip constraint and fracture-toughness

Description: Uniaxial tests of single-edged notched bend (SENB) specimens with both deep- and shallow-flaws have shown elevated fracturetoughness for the shallow flaws. The elevation in fracture-toughness for shallow flaws has been shown to be the result of reduced constraint at the crack-tip. Biaxial loading has the potential to increase constraint at the crack-tip and thereby reduce some of the shallow-flaw, fracture-toughness elevation. Biaxial fracture-toughness tests have shown that the shallow-flaw, fracture-toughness elevation is reduced but not eliminated by biaxial loading. Dual-parameter, fracture-toughness correlations have been proposed to reflect the effect of crack-tip constraint on fracture-toughness. Test results from the uniaxial and biaxial tests were analyzed using the dual-parameter technology. Discrepancies between analysis results and cleavage initiation site data from fractographic examinations indicate that the analysis models are in need of further refinement. Addition of a precleavage, ductile-tearing element to the analysis model has the potential to resolve the noted discrepancies.
Date: April 1, 1994
Creator: Pennell, W. E.; Bass, B. R.; Bryson, J. W.; McAfee, W. J.; Theiss, T. J. & Rao, M. C.
Partner: UNT Libraries Government Documents Department

Molecular Surface Chemistry by Metal Single Crystals and Nanoparticles from Vacuum to High Pressure.

Description: Model systems for studying molecular surface chemistry have evolved from single crystal surfaces at low pressure to colloidal nanoparticles at high pressure. Low pressure surface structure studies of platinum single crystals using molecular beam surface scattering and low energy electron diffraction techniques probe the unique activity of defects, steps and kinks at the surface for dissociation reactions (H-H, C-H, C-C, O{double_bond}O bonds). High-pressure investigations of platinum single crystals using sum frequency generation vibrational spectroscopy have revealed the presence and the nature of reaction intermediates. High pressure scanning tunneling microscopy of platinum single crystal surfaces showed adsorbate mobility during a catalytic reaction. Nanoparticle systems are used to determine the role of metal-oxide interfaces, site blocking and the role of surface structures in reactive surface chemistry. The size, shape and composition of nanoparticles play important roles in determining reaction activity and selectivity.
Date: April 5, 2008
Creator: Somorjai, Gabor A. & Park, Jeong Y.
Partner: UNT Libraries Government Documents Department

Restructuring of hex-Pt(100) under CO gas environments: formation of 2-D nanoclusters

Description: The atomic-scale restructuring of hex-Pt(100) induced by carbon monoxide with a wide pressure range was studied with a newly designed chamber-in-chamber high-pressure STM and theoretical calculations. Both experimental and DFT calculation results show that CO molecules are bound to Pt nanoclusters through a tilted on-top configuration with a separation of {approx}3.7-4.1 {angstrom}. The phenomenon of restructuring of metal catalyst surfaces induced by adsorption, and in particular the formation of small metallic clusters suggests the importance of studying structures of catalyst surfaces under high pressure conditions for understanding catalytic mechanisms.
Date: April 24, 2009
Creator: Tao, Feng; Dag, Sefa; Wang, Lin-Wang; Liu, Zhi; Butcher, Derek; Salmeron, Miquel et al.
Partner: UNT Libraries Government Documents Department

Acoustic emission experiments for safety of nuclear reactor vessels

Description: Acoustic emission monitoring was used in hydrostatic experiments on flawed pressure vessels and thermal shock experiments on flawed cylindrical specimens. The results of the experiments are discussed.
Date: April 26, 1976
Creator: Ying, S. P.
Partner: UNT Libraries Government Documents Department

Stress and phase transformation phenomena in oxide films

Description: In situ optical methods are reviewed for characterization of phase transformation processes and evaluation of residual stress in solution- deposited metastable oxide films. Such low density films most often are deposited as disordered phases making them prone to crystallization and attendant densification when subjected to increased temperature and/or applied pressure. Inherent stress imparted during film deposition and its evolution during the transformation are evaluated from phonon frequency shifts seen in Raman spectra (TiO{sub 2}) or from changes in the laser-induced fluorescence emission spectra for films containing rare earth (Sm{sup +3}:Y{sub 3}Al{sub 5}O{sub 12}) or transition metal (Cr{sup +3}:Al{sub 2}O{sub 3}) dopants. The data in combination with measured increases in line intensities intrinsic to the evolving phase are used to follow crystallization processes in thin films. In general, film deposition parameters are found to influence the crystallite ingrowth kinetics and the magnitude of stress and stress relaxation in the film during the transformation. The utility of these methods to probe crystallization phenomena in oxide films will be addressed.
Date: April 1, 1992
Creator: Exarhos, G.J. & Hess, N.J.
Partner: UNT Libraries Government Documents Department

Beneficial effects of groundwater entry into liquid-dominated geothermal systems

Description: In all active liquid-dominated geothermal systems there is continuous circulation of mass and transfer of heat, otherwise they would slowly cool and fade away. In the natural state these systems are in dynamic equilibrium with the surrounding colder groundwater aquifers. The ascending geothermal fluids cool conductively, boil, or mix with groundwaters, and ultimately may discharge at the surface as fumaroles or hot springs. With the start of fluid production and the lowering of reservoir pressure, the natural equilibrium is disrupted and cooler groundwater tends to enter the reservoir. Improperly constructed or damaged wells, and wells located near the margins of the geothermal system, exhibit temperature reductions (and possibly scaling from mixing of chemically distinct fluids) as the cooler-water moves into the reservoir. These negative effects, especially in peripheral wells are, however, compensated by the maintenance of reservoir pressure and a reduction in reservoir boiling that might result in mineral precipitation in the formation pores and fractures. The positive effect of cold groundwater entry on the behavior of liquid-dominated system is illustrated by using simple reservoir models. The simulation results show that even though groundwater influx into the reservoir causes cooling of fluids produced from wells located near the cold-water recharge area, it also reduces pressure drawdown and boiling in the exploited zone, and sweeps the heat stored in the reservoir rocks toward production wells, thus increasing the productive life of the wells and field. 9 refs.
Date: April 1, 1990
Creator: Lippmann, M.J. (Lawrence Berkeley Lab., CA (USA)) & Truesdell, A.H. (Geological Survey, Menlo Park, CA (USA))
Partner: UNT Libraries Government Documents Department

Effect of total pressure on graphite oxidation. [HTGR]

Description: Graphite corrosion in the high-temperature gas-cooled reactor (HTGR) is calculated using two key assumptions: (1) the kinetic, catalysis, and transport characteristics of graphite determined by bench-scale tests apply to large components at reactor conditions and (2) the effects of high pressure and turbulent flow are predictable. To better understand the differences between laboratory tests and reactor conditions, a high-pressure test loop (HPTL) has been constructed and used to perform tests at reactor temperature, pressure, and flow conditions. The HPTL is intended to determine the functional dependence of oxidation rate and characteristics on total pressure and gas velocity and to compare the oxidation results with calculations using models and codes developed for the reactor.
Date: April 1, 1983
Creator: Burnette, R.D. & Hoot, C.G.
Partner: UNT Libraries Government Documents Department

SSC 50 mm collider dipole cryostat design

Description: The cryostat of a Superconducting Super Collider (SSC) dipole magnet consists of all magnet components except the magnet assembly itself. It serves to support the magnet accurately and reliably within the vacuum vessel, provide all required cryogenic piping, and to insulate the cold mass from heat radiated and conducted from the environment. It must function reliably during storage, shipping and handling, normal magnet operation, quenches, and seismic excitations, and must be manufacturable at low cost. The major components of the cryostat are the vacuum vessel, thermal shields, multilayer insulation system, cryogenic piping, interconnections, and suspension system. The overall design of a cryostat for superconducting accelerator magnets requires consideration of fluid flow, proper selection of materials for their thermal and structural performance at both ambient and operating temperature, and knowledge of the environment to which the magnets will be subjected over the course of their expected operating life. This paper describes the design of the current SSC dipole magnet cryostat and includes discussions on the structural and thermal considerations involved in the development of each of the major systems.
Date: April 1, 1992
Creator: Nicol, T.H.
Partner: UNT Libraries Government Documents Department

The Mark III vertex chamber: Studies using DME

Description: Studies have been performed using a prototype of a pressurized wire vertex chamber with 8 mm diameter straw geometry. A 35 ..mu..m spatial resolution using dimethyl ether (DME) at 1 bar and 30 ..mu..m using argon ethane (50/50 mixture) at 4 bar was obtained. Preliminary studies show the DME to adversely affect such materials as aluminized Mylar and Delrin.
Date: April 1, 1987
Creator: Pitman, D.
Partner: UNT Libraries Government Documents Department

Geophysical monitoring of injected fluids

Description: During injection, a pressure front, fluid front, and thermal front are formed, and move away from the injection well. The performance of a geothermal field is determined by the movement of these fronts through it. The Brine Injection Technology Program is developing modeling and measurement techniques to help industry determine where these fronts are and to predict their evolution. Because these fronts change the physical properties of the reservoir medium as they pass, Lawrence Livermore National Laboratory is studying the application of geophysical methods to provide information about the location of fronts away from observation and sampling wells. The ultimate purpose is to model the behavior of the field and predict its performance. In FY86, we concentrated on collecting microseismicity and electrical self potential data before and after the start-up of a moderate sized geothermal plant. In FY 87, we will complete the analysis of these data sets, and continue collecting case history information.
Date: April 1, 1987
Creator: Kasameyer, P.W.
Partner: UNT Libraries Government Documents Department

Specific heat of (U/sub 0. 97/Th/sub 0. 03/)Be/sub 13/ under pressure

Description: The specific heat, C, of (U/sub 0.97/Th/sub 0.03/)Be/sub 13/ has been measured for 0.1 less than or equal to T less than or equal to 1K and 1.6 less than or equal to P less than or equal to 7.7 kbar, and for 0.1 less than or equal to T less than or equal to 20K with P = 0. For T > 8K both the pure and Th substituted samples have essentially the same C. The peaks in C/T at 0.33 and 0.54 for P = 0 are suppressed and shifted to lower T by pressure. Anomalies in C/T can be correlated to corresponding rapid changes in magnetic susceptibility, chi. Rapid suppression of the peaks and shift of T/sub c/ to lower values is in marked contrast to the behavior found for pure UBe/sub 13/ whose single peak amplitude decreases approximately linearly with P to about 60% at 9.3 kbar. The broad ''shoulder'' in C/T near 2K that is found for UBe/sub 13/, but not for any other heavy-fermion compound, HFC, is completely suppressed in the Th substituted sample.
Date: April 1, 1987
Creator: Fisher, R.A.; Lacy, S.E.; Marcenat, C.; Olsen, J.A.; Phillips, N.E.; Fisk, Z. et al.
Partner: UNT Libraries Government Documents Department

Evaporation of mesons from quark-gluon plasma by fission of chromoelectric flux tubes

Description: The chromoelectric flux tube model is used to obtain a dynamical description of the evaporation of mesons from a quark-gluon plasma. The radiation pressure is computed to assess whether this process is an important mode for the disassembly of a compressed plasma. A new result for the creation rate of q anti q pairs in a constant color field is employed.
Date: April 1, 1983
Creator: Glendenning, N.K.; Banerjee, B. & Matsui, T.
Partner: UNT Libraries Government Documents Department

Effect of torus wall flexibility on hydro-structural interaction in BWR containment system

Description: The MARK I boiling water reactor (BWR) containment system is comprised of a light-bulb-shaped reactor compartment connected through vent pipes to a torus-shaped and partially water-filled pressure suppression chamber, or the wetwell. During either a normally occurring safety relief valve (SRV) discharge or a hypothetical loss-of-coolant accident (LOCA), air or steam is forced into the wetwell water pool for condensation and results in hydrodynamically induced loads on the torus shell. An analytical program is described which employs the finite element method to investigate the influence of torus wall flexibility on hydrodynamically induced pressure and the resultant force on the torus shell surface. The shell flexibility is characterized by the diameter-to-thickness ratio which is varied from the perfectly rigid case to the nominal plant condition. The general conclusion reached is that torus wall flexibility decreases both the maximum pressure seen by the shell wall and the total vertical load resulted from the hydrodynamically induced pressure.
Date: April 25, 1979
Creator: Lu, S.C.H.; McCauley, E.W. & Holman, G.S.
Partner: UNT Libraries Government Documents Department

CHEMICALLY VAPOR DEPOSITED YTTRIA-STABILIZED ZIRCONIA (YSZ) FOR THERMAL AND ENVIRONMENTAL BARRIER COATING

Description: Yttria-stabilized zirconia (YSZ) is used as a thermal barrier coating (TBC) to protect super-alloy blades such as Mar-M247 or Rene-N5 during engine operation. The current method for YSZ fabrication for TBC applications is by air-plasma spraying (APS) or electron beam physical vapor deposition (EB-PVD) (Haynes 1997). APS gives reasonable deposition rates, but has a limited life and aging effects due to its porous and lamellar structure. The EB-PVD coatings are more stable and can accommodate thermomechanical stresses due to their characteristic strain-tolerant, columnar microstructure. EB-PVD, however, is primarily line-of-sight, which often leaves ''hidden areas'' uncoated, has low throughput, and has high capital cost. The process of metal-organic chemical vapor deposition (MOCVD) is investigated here as an economical alternative to EB-PVD and APS, with the potential for better overall coverage as well as the ability to produce thick (100-250 {micro}m), strain-tolerant, columnar coatings. MOCVD of YSZ involves the use of zirconium and yttrium organometallic precursors reacting with an oxygen source. Previous researchers have used diketonate or chloride precursors and oxygen (Wahl et al. 2001a, Wahl et al. 2001b, Yamane and Harai 1989). These precursors have low transport rates due to their low carrier solvent solubility (Varanasi et al. 2003). Solvated zirconium and yttrium butoxide precursors were investigated here due to their higher vapor pressures and high solvent solubility. This work uses predictive equilibrium modeling and experiments involving butoxide precursors for tetragonal YSZ fabrication.
Date: April 22, 2003
Creator: Varanasi, V.G.; Besmann, T.M.; Lothian, J.L.; Xu, W. & Starr, T.L.
Partner: UNT Libraries Government Documents Department

Physical model of lean suppression pressure oscillation phenomena: steam condensation in the light water reactor pressure suppression system (PSS)

Description: Using the results of large scale multivent tests conducted by GKSS, a physical model of chugging is developed. The unique combination of accurate digital data and cinematic data has provided the derivation of a detailed, quantified correlation between the dynamic physical variables and the associated two-phase thermo-hydraulic phenomena occurring during lean suppression (chugging) phases of the loss-of-coolant accident in a boiling water reactor pressure suppression system.
Date: April 1, 1980
Creator: McCauley, E.W.; Holman, G.S.; Aust, E.; Schwan, H. & Vollbrandt, J.
Partner: UNT Libraries Government Documents Department

Method for chug classification

Description: A method is presented which classifies the late time condensation phenomena of chugging as it occurs in pressure suppression tests. The method uses a five (5) character letter code which describes both the spectral (frequency) and temporal characteristics of a chug event. 8 figures.
Date: April 1, 1981
Creator: McCauley, E.W.; Weaver, H.J. & Altenbach, T.J.
Partner: UNT Libraries Government Documents Department

Permeability of generic repository rocks at simulated in situ conditions. [Comparison of Westerly granite and White Lake genissic granite]

Description: New laboratory data are reported on the effect of confining (lithostatic) pressure, pore-water pressure, and principal stress difference on permeability of Westerly granite and White Lake gneissic granite. Permeabilities as low as 10/sup -19/ cm/sup 2/ (10/sup -11/ D) have been measured successfully, using a transient technique. Principal strains, electrical conductivity, and compressional velocity are determined simultaneously. Applied loads on the 15-cm diameter by 28-cm long test sample are controlled automatically and all data are taken by a microcomputer. Results on the gneissic granite indicate permeabilities of 10/sup -18/ to 10/sup -19/ cm/sup 2/ that appear to be unaffected either by effective pressure or by stress. The granite yields permeabilities of 4x10/sup -16/ cm/sup 2/ that decrease by a factor of two with pressure and vary by a factor of two with stress. When compared to the initial value, compressional velocities increase by 4% and conductivity decreases by 50% as pressure is increased to 50 MPa in the gneissic granite. In granite, these become 3% and 58%, respectively. At pressure, loading of the granite of 0.5 of failure stress increases conductivity by about 20%.
Date: April 23, 1979
Creator: Heard, H.C.; Trimmer, D.; Duba, A. & Bonner, B.
Partner: UNT Libraries Government Documents Department

Planetary fluids He and NH/sub 3/ at high shock pressures and temperatures

Description: Liquid He at 4.3 K and 1 atm was shocked to 16 GPa (160 kbar) and 12,000 K and double-shocked to 56 GPa and 21,000 K. Liquid perturbation theory was used to determine an effective interatomic potential from which the equation of state of He can be obtained over a wide range of densities and temperatures in the envelopes of the outer planets. A new fast optical pyrometer and a cryogenic specimen holder for liquid NH/sub 3/ were developed to measure shock temperatures of 4400 and 3600 K at pressures of 59 and 48 GPa. These conditions correspond to those in the ice layers in Uranus and Neptune. The shock temperature data are in reasonable agreement with an equation of state by Ree based on an intermolecular potential derived from NH/sub 3/ Hugoniot data.
Date: April 1, 1985
Creator: Nellis, W.J.; Radousky, H.B.; Mitchell, A.C.; Holmes, N.C.; Ross, M. & Young, D.A.
Partner: UNT Libraries Government Documents Department

Task 1 Steam Oxidation (NETL-US)

Description: Some conclusions are: (1) Increased flow rates can lower chromia activity in alloys with Ti and Mn - (a) Reduced chromia activity reduces equilibrium CrO{sub 2}(OH){sub 2}(g) vapor pressures; (2) Model is very sensitive to small decreases in chromia activity at the HP turbine - (a) Upstream partial saturation of the gas phase with CrO{sub 2}(OH){sub 2}(g) can become nearly or fully saturated at the HP turbine, (b) Can radically change breakaway oxidation times from less than a year to never happening; and (3) Thus even small chromia activity reductions from Ti and Mn additions can make evaporation issues self-correcting.
Date: April 28, 2011
Creator: Holcomb, G. R.; Tylczak, J. & R. Hu,
Partner: UNT Libraries Government Documents Department