Bibliografías temáticas / Forschungszentrum Rossendorf

Índice

Artículos de revistas
Tesis
Libros
Actas de conferencias

Literatura académica sobre el tema "Forschungszentrum Rossendorf"

Autor: Grafiati

Publicado: 4 de junio de 2021

Última modificación: 1 de febrero de 2022

Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros

Elija tipo de fuente:

Consulte las listas temáticas de artículos, libros, tesis, actas de conferencias y otras fuentes académicas sobre el tema "Forschungszentrum Rossendorf".

Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.

También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.

Artículos de revistas sobre el tema "Forschungszentrum Rossendorf"

Dittes, K. "Wandlung in Rossendorf: Das Forschungszentrum Rossendorf vier Jahre nach seiner Gründung". Physik Journal 52, n.º 6 (junio de 1996): 577–79. http://dx.doi.org/10.1002/phbl.19960520613.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Brauer, Gerhard, W. Wendler, H. Büttig, F. Gabriel, P. Gippner, W. Gläser, E. Grosse et al. "The ELBE Radiation Source Project at the Forschungszentrum Rossendorf". Materials Science Forum 255-257 (septiembre de 1997): 732–34. http://dx.doi.org/10.4028/www.scientific.net/msf.255-257.732.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Grosse, E. "Die Strahlungsquelle ELBE am Forschungszentrum Rossendorf: Grundsteinlegung und erstes Nutzertreffen". Physik Journal 54, n.º 4 (abril de 1998): 342–44. http://dx.doi.org/10.1002/phbl.19980540411.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Krause-Rehberg, R., M. Jungmann, A. Krille, B. Werlich, A. Pohl, W. Anwand, G. Brauer et al. "Use of superconducting linacs for positron generation: the EPOS system at the Forschungszentrum Dresden-Rossendorf (FZD)". Journal of Physics: Conference Series 262 (1 de enero de 2011): 012003. http://dx.doi.org/10.1088/1742-6596/262/1/012003.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

DÖRR, M., D. ECKERT, H. ESCHRIG, F. FISCHER, P. FULDE, R. GROESSINGER, W. GRÜNBERGER et al. "THE DRESDEN 100 T/10 ms PROJECT: A HIGH MAGNETIC FIELD FACILITY AT AN IR-FEL". International Journal of Modern Physics B 16, n.º 20n22 (30 de agosto de 2002): 3397. http://dx.doi.org/10.1142/s0217979202014541.

Texto completo

Resumen

We have proposed to build a 100 T/10 ms, 70 T/100 ms, 60 T/1 s pulsed field user facility with a 50 MJ capacitor bank at the Forschungszentrum Rossendorf near Dresden. This would provide the appealing possibility to have access to Zeeman energies in the energy range of the infrared free-electron-lasers (5 μm to 150 μm; 2 ps; cw; > 10 W) now under construction at the radiation source ELBE (superconducting electron linear accelerator; 40 MeV; 1 mA; 2 ps; cw) in Rossendorf. The work is accompanied by computer simulations of the planned coil systems, of the power supply, and by the development of high-strength conductors aiming at a tensile strength of about 1.5 GPa at σ ≈ σ Cu/2 (microcomposite CuAg alloys and Cu-steel macro compounds). With a view of gaining experience in the construction and operation of pulsed magnets, a pilot pulsed field laboratory was established at the Institute of Solid State and Materials Research Dresden (IFW Dresden). The laboratory includes short pulse magnets with peak field up to 60 T in a 24 mm bore and a rise time of about 10 ms (coil from NHMFL, Tallahassee), and a 40 T long pulse magnet with 24 mm bore and rise time of about 80 ms (coil from METIS, Leuven). The repetition rate of 20 min between pulses is limited by the cooling time of the coils. The coils are energized by a 1 MJ, 10 kV capacitor bank with some special features. With this set-up measurements of magnetization and magnetotransport on 4f-electron systems, for example RECu2, have been out in the temperature range of 1.5 to 300 K and at fields up to 52 T using high precision pick-up coils.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Wester, Hans-Jürgen. "Detailreich und lebendig: Georg von Hevesy. Wissenschaflter ohne Grenzen. Von Siegfried Niese. Forschungszentrum Rossendorf 2005. 187 Seiten. 25,- Euro. ISBN 3-00-015374-8". Nachrichten aus der Chemie 53, n.º 10 (octubre de 2005): 1065–66. http://dx.doi.org/10.1002/nadc.20050531033.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Deju, L., S. C. P. Cheung, G. H. Yeoh y J. Tu. "Study of Isothermal Vertical Bubbly Flow Using Direct Quadrature Method of Moments". Journal of Computational Multiphase Flows 4, n.º 1 (marzo de 2012): 23–39. http://dx.doi.org/10.1260/1757-482x.4.1.23.

Texto completo

Resumen

In the numerical study, investigation of bubbly flow requires deep understanding of complex hydrodynamics under various flow conditions. In order to simulate the bubble behaviour in conjunction with suitable bubble coalescence and bubble breakage kernels, direct quadrature method of moments (DQMOM) has been applied and validated instead. To examine the predictive results from DQMOM model, the validation has been carried out against experimental data of Lucas et al. (2005) and Prasser et al. (2007) measured in the Forschungszentrum Dresden-Rossendorf FZD facility. Numerical results showed good agreement against experimental data for the local and axial void fraction, bubble size distribution and interfacial area concentration profiles. Encouraging results demonstrates the prospect of the DQMOM two-fluid model against flow conditions with wider range of bubble sizes and rigorous bubble interactions. Moreover, moment sensitivity study also has been carried out to carefully assess the performance of the model. In order to perform the moment sensitivity test three different moment criteria has chosen – as 4 moments, 6 moments and 8 moments. Close agreement between the predictions and measurement was found and it appeared that increasing the number of moments does not have much significance to improve the conformity with experimental data. Nonetheless, increasing the number of moments merely contribute to perform the calculation expensive in terms of computational resource and time. Based on the present study, this preliminary assessment has definitely served to demonstrate and exploit DQMOM model's capabilities to handle wider range of bubble sizes as well as moment resolution required to achieve moment independent solution.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Vallée, Christophe, Tobias Seidel, Dirk Lucas, Akio Tomiyama y Michio Murase. "Comparison of Countercurrent Flow Limitation Experiments Performed in Two Different Models of the Hot Leg of a Pressurized Water Reactor With Rectangular Cross Section". Journal of Engineering for Gas Turbines and Power 133, n.º 5 (28 de diciembre de 2010). http://dx.doi.org/10.1115/1.4002884.

Texto completo

Resumen

In order to investigate the two-phase flow behavior during countercurrent flow limitation in the hot leg of a pressurized water reactor, two test models were built: one at the Kobe University and the other at the TOPFLOW test facility of Forschungszentrum Dresden-Rossendorf (FZD). Both test facilities are devoted to optical measurement techniques; therefore, a flat hot leg test section design was chosen. Countercurrent flow limitation (CCFL) experiments were performed, simulating the reflux condenser cooling mode appearing in some accident scenarios. The fluids used were air and water, both at room temperature. The pressure conditions were varied from atmospheric at Kobe to 3.0 bars absolute at TOPFLOW. According to the presented review of literature, very few data are available on flooding in channels with a rectangular cross section, and no experiments were performed in the past in such flat models of a hot leg. Commonly, the macroscopic effects of CCFL are represented in a flooding diagram, where the gas flow rate is plotted versus the discharge water flow rate, using the nondimensional superficial velocity (also known as Wallis parameter) as coordinates. However, the classical definition of the Wallis parameter contains the pipe diameter as characteristic length. In order to be able to perform comparisons with pipe experiments and to extrapolate to the power plant scale, the appropriate characteristic length should be determined. A detailed comparison of the test facilities operated at the Kobe University and at FZD is presented. With respect to the CCFL behavior, it is shown that the essential parts of the two hot leg test sections are very similar. This geometrical analogy allows us to perform meaningful comparisons. However, clear differences in the dimensions of the cross section (H×W=150×10 mm2 in Kobe, 250×50 mm2 at FZD) make it possible to point out the right characteristic length for hot leg models with rectangular cross sections. The hydraulic diameter, the channel height, and the Laplace critical wavelength (leading to the Kutateladze number) were tested. A comparison of our own results with similar experimental data and empirical correlations for pipes available in literature shows that the channel height is the characteristic length to be used in the Wallis parameter for channels with rectangular cross sections. However, some limitations were noticed for narrow channels, where CCFL is reached at lower gas fluxes, as already observed in small scale hot legs with pipe cross sections.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Vallée, Christophe, Deendarlianto, Matthias Beyer, Dirk Lucas y Helmar Carl. "Air/Water Counter-Current Flow Experiments in a Model of the Hot Leg of a Pressurized Water Reactor". Journal of Engineering for Gas Turbines and Power 131, n.º 2 (5 de enero de 2009). http://dx.doi.org/10.1115/1.3043816.

Texto completo

Resumen

Different scenarios of small break loss of coolant accident for pressurized water reactors (PWRs) lead to the reflux-condenser mode in which steam enters the hot leg from the reactor pressure vessel (RPV) and condenses in the steam generator. A limitation of the condensate backflow toward the RPV by the steam flowing in counter current could affect the core cooling and must be prevented. The simulation of counter-current flow limitation conditions, which is dominated by 3D effects, requires the use of a computational fluid dynamics (CFD) approach. These numerical methods are not yet mature, so dedicated experimental data are needed for validation purposes. In order to investigate the two-phase flow behavior in a complex reactor-typical geometry and to supply suitable data for CFD code validation, the “hot leg model” was built at Forschungszentrum Dresden-Rossendorf (FZD). This setup is devoted to optical measurement techniques, and therefore, a flat test-section design was chosen with a width of 50 mm. The test section outlines represent the hot leg of a German Konvoi PWR at a scale of 1:3 (i.e., 250 mm channel height). The test section is mounted between two separators, one simulating the RPV and the other is connected to the steam generator inlet chamber. The hot leg model is operated under pressure equilibrium in the pressure vessel of the TOPFLOW facility of FZD. The air/water experiments presented in this article focus on the flow structure observed in the region of the riser and of the steam generator inlet chamber at room temperature and pressures up to 3 bar. The performed high-speed observations show the evolution of the stratified interface and the distribution of the two-phase mixture (droplets and bubbles). The counter-current flow limitation was quantified using the variation in the water levels measured in the separators. A confrontation with the images indicates that the initiation of flooding coincides with the reversal of the flow in the horizontal part of the hot leg. Afterward, bigger waves are generated, which develop to slugs. Furthermore, the flooding points obtained from the experiments were compared with empirical correlations available in literature. A good overall agreement was obtained, while the zero penetration was found at lower values of the gaseous Wallis parameter compared with previous work. This deviation can be attributed to the rectangular cross section of the hot leg model.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Tesis sobre el tema "Forschungszentrum Rossendorf"

Leib, Jürgen. "Forschungszentrum Rossendorf; Jahresbericht 1997". Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-30469.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Leib, Jürgen. "Forschungszentrum Rossendorf; Jahresbericht 1997". Forschungszentrum Rossendorf, 1998. https://hzdr.qucosa.de/id/qucosa%3A21873.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Fülle, Ruprecht. "Forschungszentrum Rossendorf; Jahresbericht 1993/94". Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-31889.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Fülle, Ruprecht. "Forschungszentrum Rossendorf; Jahresbericht 1993/94". Forschungszentrum Rossendorf, 1995. https://hzdr.qucosa.de/id/qucosa%3A22015.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Ottow, S. "Jahresbericht 2. Halbjahr 1999/2000 Forschungszentrum Rossendorf". Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-29561.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Leib, Jürgen. "Forschungszentrum Rossendorf; Jahresbericht 1998/1. Halbjahr 1999". Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-30124.

Texto completo

Resumen

Der zentrumsübergreifenden Jahresbericht gibt einen Überblick über die Forschungsarbeiten des Forschungszentrum Rossendorf e. V. (FZR) und seiner fünf Institute. Die anwendungsorientierte Grundlagenforschung des FZR mit den Schwerpunkten Materialforschung, Biomedizin-Chemie, Umwelt, Sicherheitsforschung, Kern- und Strahlungsphysik trägt zur Lösung wichtiger Probleme unserer Zeit bei. Das Forschungszentrum ist Mitglied der Wissenschaftsgemeinschaft Gottfried Wilhelm Leibniz (WGL) unter deren Dach 79 nationale Forschungseinrichtungen vereint sind und wird je zur Hälfte von der Bundesrepublik Deutschland und den Ländern getragen. Mit seinen rund 620 Mitarbeitern und einem Jahresetat von etwa 100 Mio. DM stellt das FZR die größte Einrichtung der WGL dar und ist zugleich auch die größte außeruniversitäre Forschungseinrichtung in den neuen Ländern. Die wissenschaftliche Arbeit des FZR wird in fünf Instituten durchgeführt: - Institut für Ionenstrahlphysik und Materialforschung - Institut für Bioanorganische und Radiopharmazeutische Chemie - Institut für Radiochemie - Institut für Kern- und Hadronenphysik - Institut für Sicherheitsforschung. Sie werden hierbei unterstützt durch die Zentralabteilungen: - Forschungs- und Informationstechnik - Neue Beschleuniger und die Projektgruppen: - ESRF-Beam-Line - ELBE-Quelle. Im Jahresbericht 1998/99 finden Sie populärwissenschaftliche Artikel über Ergebnisse ausgewählter Arbeiten am FZR zu folgenden Themen: * Elektromagnetische Umströmungskontrolle in schwach-leitfähigen Flüssigkeiten * Charakterisierung gestörter regionaler Hirnfunktionen mit Hilfe von PET * Bakterien in Uranabfallhalden und ihre Wechselwirkung mit Uran * Ionen-Nitrierung von Aluminiumwerkstoffen * Seltsame Kaonen, hadronische Materie und kosmische Phasenübergänge * Wissen schafft Fortschritt - Forschungs- und Wissenstransfer am FZR

Los estilos APA, Harvard, Vancouver, ISO, etc.

Ottow, S. "Jahresbericht 2. Halbjahr 1999/2000 Forschungszentrum Rossendorf". Forschungszentrum Rossendorf, 2001. https://hzdr.qucosa.de/id/qucosa%3A21783.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Leib, Jürgen. "Forschungszentrum Rossendorf; Jahresbericht 1998/1. Halbjahr 1999". Forschungszentrum Rossendorf, 1999. https://hzdr.qucosa.de/id/qucosa%3A21839.

Texto completo

Resumen

Los estilos APA, Harvard, Vancouver, ISO, etc.

Einfeld, D. y W. Matz. "ROSY - Rossendorfer Synchrotronstrahlungsquelle, Vorschlag für die Errichtung einer Synchrotronstrahlungsquelle für die Materialforschung im Forschungszentrum Rossendorf". Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-28373.

Texto completo

Resumen

Der Projektvorschlag für eine kompakte Synchrotronstrahlungsquelle der 3. Generation ROSY wird beschrieben. Die Quelle sol1 für die Materialforschung dediziert sein, die für die Forschung im regionalen Umfeld von Rossendorf prägend ist. Bei einer Speicherringenergie von 3 GeV wird Synchrotronstrahlung im harten Röntgenbereich mit einer kritischen Energie des Spektrums von Ec = 8,4 keV (hc=0,14 nm) emittiert. Mit einer naturlichen Emittanz von 28 n nm rad wird eine sehr brillante Strahlung zur Verfügung gestellt. Neben der Strahlung aus Ablenkmagneten kann Strahlung aus Wigglern und Undulatoren genutzt werden. Für diese insertion devices sind 8 Einbaumöglichkeiten vorhanden, von denen 4 in nichtdispersionsfreien geraden Strecken liegen. Der Speicherring hat eine vierfache Symmmetrie, einen Umfang von 148 m und ist als modifizierte FODO-Struktur konzipiert. Ein nachträglicher Einbau von supraleitenden Ablenkmagneten zur Erzeugung eines harteren Spektrums und damit zur Ausweitung des Anwendungsbereiches ist möglich. Der Teil I enthält die wissenschaftliche Begründung fur ROSY und eine Darstellung der Nutzungsmöglichkeiten. Im Teil II werden das Speicherringkonzept und die technischen Details der einzelnen Komponenten beschrieben.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Einfeld, D. y W. Matz. "ROSY - Rossendorfer Synchrotronstrahlungsquelle, Vorschlag für die Errichtung einer Synchrotronstrahlungsquelle für die Materialforschung im Forschungszentrum Rossendorf". Forschungszentrum Rossendorf, 1992. https://hzdr.qucosa.de/id/qucosa%3A21664.

Texto completo

Resumen

Los estilos APA, Harvard, Vancouver, ISO, etc.

Más fuentes

Libros sobre el tema "Forschungszentrum Rossendorf"

W, Matz y Einfeld D, eds. ROSY: Rossendorfer Synchrotronstrahlungsquelle : Vorschlag für die Errichtung einer Synchrotronstrahlungsquelle für die Materialforschung im Forschungszentrum Rossendorf. Dresden: Forschungszentrum Rossendorf, 1992.

Buscar texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Actas de conferencias sobre el tema "Forschungszentrum Rossendorf"

Michel, P. "The radiation source ELBE at the Forschungszentrum Dresden-Rossendorf". En 2008 IEEE Nuclear Science Symposium and Medical Imaging conference (2008 NSS/MIC). IEEE, 2008. http://dx.doi.org/10.1109/nssmic.2008.4775006.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Krepper, Eckhard, Attila Aszo´di y Frank-Peter Weiss. "Experimental and Numerical Investigations of Heating Up Processes of Fluids in Large Pools". En ASME 2002 Joint U.S.-European Fluids Engineering Division Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/fedsm2002-31406.

Texto completo

Resumen

Heating up experiments at the secondary pools side of the NOKO test facility were performed, to investigate mixed convection phenomena. The NOKO test facility was designed to investigate the heat transfer capability of an emergency condenser and was operated in the Research Centre Ju¨lich. In the Forschungszentrum Rossendorf the heating up tests were analyzed by CFD-simulations using the AEA-Technology code CFX-4. Applying the Boussinesq approximation the simulation of the heating up process is possible, at least qualitatively. Using the laminar approach, temperature oscillations caused by plumes could be simulated. A further test series performed at Forschungszentrum Rossendorf deals with the investigation of transient boiling. Heating up a 10 l water tank from the side walls, the temperatures and the void fractions at different locations in the tank were measured. CFX-4 simulations using the implemented boiling model reproduce and explain the observed phenomena. Convergence problems occurred with higher vapor volume fractions.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Krepper, Eckhard, Gregory Cartland-Glover, Alexander Grahn, Frank-Peter Weiss, So¨ren Alt, Rainer Hampel, Wolfgang Ka¨stner y Andre´ Seeliger. "Experimental Investigation and CFD Simulation of the Behaviour of Mineral Wool in the Reactor Sump". En 16th International Conference on Nuclear Engineering. ASMEDC, 2008. http://dx.doi.org/10.1115/icone16-48121.

Texto completo

Resumen

The investigation of insulation debris generation, transport and sedimentation becomes important with regard to reactor safety research for PWR and BWR, when considering the long-term behavior of emergency core cooling systems during all types of loss of coolant accidents (LOCA). The insulation debris released near the break during a LOCA incident consists of a mixture of disparate particle population that varies with size, shape, consistency and other properties. Some fractions of the released insulation debris can be transported into the reactor sump, where it may perturb/impinge on the emergency core cooling systems. Open questions of generic interest are the sedimentation of the insulation debris in a water pool, its possible re-suspension and transport in the sump water flow and the particle load on strainers and corresponding pressure drop. A joint research project on such questions is being performed in cooperation between the University of Applied Sciences Zittau/Go¨rlitz and the Forschungszentrum Dresden-Rossendorf. The project deals with the experimental investigation of particle transport phenomena in coolant flow and the development of CFD models for its description. While the experiments are performed at the University at Zittau/Go¨rlitz, the theoretical modeling efforts are concentrated at Forschungszentrum Dresden-Rossendorf. In the current paper the basic concepts for CFD modeling are described and feasibility studies including the conceptual design of the experiments are presented.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Krepper, Eckhard, Frank-Peter Weiss, So¨ren Alt, Alexander Kratzsch, Stefan Renger y Wolfgang Ka¨stner. "Some Nuclear Reactor Safety Related Aspects of Plunging Jets". En 18th International Conference on Nuclear Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/icone18-29951.

Texto completo

Resumen

Plunging jets play an important role in nuclear reactor safety research. In the present paper the case of the strainer clogging issue is considered. Entrained air caused by a plunging jet has an influence of the liquid flow field and on the fibre transport in the sump. In the paper the amount of entrained air is given as an inlet boundary condition according to correlations in the literature and confirmed by own experiments. The influence of entrained air on the fibre deposition pattern at the bottom of a tank and on the mixing procedure for the case of temperature differences between jet and tank water are investigated by CFD calculations and compared to experiments. The presented work is part of a joint research project performed in cooperation between the University of Applied Science Zittau/Go¨rlitz and Forschungszentrum Dresden-Rossendorf. The project deals with the experimental investigation of particle transport phenomena in coolant flow in Zittau and the development of CFD models for its simulation in Rossendorf (Krepper et al. 2008).

Los estilos APA, Harvard, Vancouver, ISO, etc.

Murase, Michio, Ikuo Kinoshita, Yoichi Utanohara, Dirk Lucas, Christophe Valle´e y Akio Tomiyama. "Numerical Calculations for Air-Water Tests on CCFL in Different-Scale Models of a PWR Hot Leg". En 18th International Conference on Nuclear Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/icone18-29092.

Texto completo

Resumen

Air-water CCFL (countercurrent flow limitation) tests using the 1/5th scale rectangular channel and 1/15th scale circular tube simulating a PWR hot leg and both air-water and steam-water CCFL tests using the 1/3rd scale rectangular channel were previously carried out at Kobe University and Forschungszentrum Dresden-Rossendorf (FZD), respectively. In this paper, numerical calculations for the air-water CCFL tests at FZD using FLUENT6.3.26 are presented and compared with the experimental data at Kobe University and FZD. In the calculations, the VOF (volume of fluid) model or two-fluid (2F) model was used. Major results were as follows: (1) the calculated CCFL characteristics using the 2F model for the FZD tests agreed well with the 1/15th scale circular tube data obtained at Kobe University and the calculated results for full-scale PWR conditions, which supported the validity of the 1/3rd scale rectangular channel to simulate CCFL in circular tubes; and (2) comparison with the FZD data showed that the calculations using the 2F and VOF models overestimated the falling water flow rates.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Guillen, Donna Post, Jonathan K. Shelley, Steven P. Antal, Elena A. Tselishcheva, Michael Z. Podowski, Dirk Lucas y Matthias Beyer. "Optimization of a Two-Fluid Hydrodynamic Model of Churn-Turbulent Flows". En 17th International Conference on Nuclear Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/icone17-75113.

Texto completo

Resumen

A hydrodynamic model of two-phase, churn-turbulent flows is being developed using the computational multiphase fluid dynamics (CMFD) code, NPHASE-CMFD. The numerical solutions obtained by this model are compared with experimental data obtained at the TOPFLOW facility of the Institute of Safety Research at the Forschungszentrum Dresden-Rossendorf. The TOPFLOW data is a high quality experimental database of upward, co-current air-water flows in a vertical pipe suitable for validation of computational fluid dynamics (CFD) codes. A five-field CMFD model was developed for the continuous liquid phase and four bubble size groups using mechanistic closure models for the ensemble-averaged Navier-Stokes equations. Mechanistic models for the drag and non-drag interfacial forces are implemented to include the governing physics to describe the hydrodynamic forces controlling the gas distribution. The closure models provide the functional form of the interfacial forces, with user defined coefficients to adjust the force magnitude. An optimization strategy was devised for these coefficients using commercial design optimization software. This paper demonstrates an approach to optimizing CMFD model parameters using a design optimization approach. Computed radial void fraction profiles predicted by the NPHASE-CMFD code are compared to experimental data for four bubble size groups.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Richter, Anke, Vinzenz Brendler, Cordula Nebelung, Timothy E. Payne y Thomas Brasser. "Sorption Databases for Increasing Confidence in Performance Assessment". En ASME 2009 12th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2009. http://dx.doi.org/10.1115/icem2009-16053.

Texto completo

Resumen

World-wide activities focus on the remediation of radioactively contaminated sites. One common aim is to deliver a more profound chemical base for risk assessment, namely all those physico-chemical phenomena governing the contamination plume development in time and space. Coupled transport codes able to tackle this challenge have to simplify the resulting very complex reaction pattern. To do so in an adequate way requires extending the knowledge about retardation and mobilisation phenomena and the underlying basic processes and interactions (e.g. physisorption, chemisorption, surface precipitation). Interactions at the solid-liquid interface can be described by complementary approaches, the empirical Kd concept and the mechanistic Surface Complexation Models (SCM). Kd’s are used by most reactive transport and risk assessment codes due to the straightforward numerics involved. In addition, the Kd concept is often the only feasible option for complex solid phases. However, the Kd concept is a rather simplistic approach. Many very different basic physico-chemical phenomena are subsumed in just one conditional parameter. Therefore, extrapolating Kd values may yield very large uncertainties. SCM account adsorption of ions on surface sites as complexation reaction comparable to complexation in solution. The electrical charge at the surface is determined by the chemical reactions of the mineral functional groups, including acid-base reactions and formation of ion pairs and coordinative complexes. The required parameters are site-independent and applicable despite large variations in geochemical conditions. This presents a high potential to increase confidence in safety analysis and risk assessment studies (performance assessment). The mechanistic description of sorption processes with SCM allows a thermodynamically consistent calculation of the species distribution between liquid and solid phase combined with more reliable inter- and extrapolations. However, this requires that all mineral constituents of the solid phase are characterized. Another issue is the large number of required parameters combined with time-consuming iterations. Addressing both approaches, we present two sorption databases, developed mainly by or under participation of the Forschungszentrum Dresden-Rossendorf (FZD). Both databases are implemented as relational databases, assist identification of critical data gaps and the evaluation of existing parameter sets, provide web based data search and analyses and permit the comparison of SCM predictions with Kd values. RES3T (Rossendorf Expert System for Surface and Sorption Thermodynamics) is a digitized thermodynamic sorption database (see www.fzd.de/db/RES3T.login) and free of charge. It is mineral-specific and can therefore also be used for additive models of more complex solid phases. ISDA (Integrated Sorption Database System) connects SCM with the Kd concept but focuses on conventional Kd. The integrated datasets are accessible through a unified user interface. An application case, Kd values in Performance Assessment, is given.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Ho¨hne, T., U. Bieder, S. Kliem y H. M. Prasser. "Validation of Trio_U: Numerical Simulations of a ROCOM Buoyancy Driven Test Case". En 12th International Conference on Nuclear Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/icone12-49487.

Texto completo

Resumen

A generic investigation of the influence of density differences between the primary loop inventory and the ECC water on the mixing in the downcomer was made at the ROCOM Mixing Test Facility at Forschungszentrum Rossendorf (FZR)/Germany. ROCOM is designed for experimental coolant mixing studies over a wide variety of possible scenarios. It is equipped with advanced instrumentation, which delivers high-resolution information characterizing either temperature or boron concentration fields in the investigated pressurized water reactor. For the validation of the Trio_U code an experiment with 5% constant flow rate in one loop (magnitude of natural circulation) and 10% density difference between ECC and loop water was taken. Trio_U is a CFD code developed by the CEA France, aimed to supply an efficient computational tool to simulate transient thermal-hydraulic single-phase turbulent flows encountered in the nuclear systems as well as in the industrial processes. For this study a LES approach was used for mesh sizes according to between 300000–2 million control volumes. The results of the experiment as well as of the numerical calculations show, that a streak formation of the water with higher density is observed. At the upper sensor, the ECC water covers a small azimuthal sector. The density difference partly suppresses the propagation of the ECC water in circumferential direction. The ECC water falls down in an almost straight streamline and reaches the lower downcomer sensor position directly below the affected inlet nozzle. Only later, coolant containing ECC water appears at the opposite side of the downcomer. The study showed, that density effects play an important role during natural convection with ECC injection in pressurized water reactors. Furthermore it was important to point out, that Trio_U is able to cope the main flow and mixing phenomena.

Los estilos APA, Harvard, Vancouver, ISO, etc.

AbdulKareem, Lokman A., S. Sharaf, Barry J. Azzopardi y Andrew Hunt. "Effect of Inclination on Slug Flow Characteristics". En ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-38119.

Texto completo

Resumen

Modern oil/gas well drilling methods in particular in the offshore industry involve deviated drilling in which the production tubing can be inclined at any angle between the vertical and the horizontal. Riser tubes from the seabed to the surface or to floating production vessels (FPSO) will also rarely be exactly vertical. This work describes a study carried out at the University Of Nottingham on the effects of inclination on gas / liquid slug flow. Two advanced tomography techniques were applied simultaneously to the flow of a mixture of air and silicone oil in a 67 mm internal diameter pipe and the pipe was inclined at various angles. A twin plane Electrical Capacitance Tomography (ECT) electrode system driven by Tomoflow electronics was positioned below a Capacitance Wire Mesh Sensor (WMS) developed at Forschungszentrum Rossendorf-Dresden/Germany M. J. Da Silva et al [2]. This enabled an examination of the flow to be carried out at several levels of complexity. Both measuring sensors provide time and cross-sectionally resolved information about the spatial distribution of the phases. Conditions studied were superficial velocities for air ranged from 0.05 to 5.5 m/s and for silicone oil ranged from 0.0 m/s to 0.5 m/s. In present paper, the effect of inclination on the phase distribution in two phase gas liquid slug flow is presented. The liquid hold up within the slug region and in the elongated bubble zone and the averaged liquid hold up were calculated from the output data of the two measurements techniques. Radial gas volume fraction profiles and bubble size distributions were also processed from the wire-mesh sensor data. The shapes of the large bubbles and waves were compared for different inclination angles. The results indicate that the pipe inclination has a significant effect on the slug flow characteristics. Both Taylor bubble and small bubbles in the slug region tend to flow along the upper pipe wall and causing significant variation of Taylor bubble rise velocity with inclination angle.

Los estilos APA, Harvard, Vancouver, ISO, etc.

AbdulKareem, Lokman A., V. Hernandez-Perez, S. Sharaf y Barry J. Azzopardi. "Characteristics of Air-Oil Slug Flow in Inclined Pipe Using Tomographic Techniques". En ASME/JSME 2011 8th Thermal Engineering Joint Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/ajtec2011-44546.

Texto completo

Resumen

The structure of gas liquid flow in horizontal and vertical pipes to some extent is well understood. However, the situation in inclined pipes is much more difficult with very little work published in literature. Changes in physical phenomena occur as the pipe inclination angle varies from the vertical through to inclined and then to horizontal. This work describes a study carried out at the University Of Nottingham on the effects of inclination on gas / liquid slug flow. Two advanced tomography techniques were applied simultaneously to the flow of a mixture of air and silicone oil in a 67 mm internal diameter pipe and the pipe was inclined at angles 0, 5, 10, 30, 45, 60, 80, 90 degrees. This paper reports on the use of twin plane electrical capacitance tomography (ECT) system developed by TomoFlow electronics Ltd to measure flow characteristics in gas-liquid flows. We report measurements over a range of liquid superficial velocities from 0.05 m/s to 0.5 m/s and gas superficial velocities from 0.06 m/s to 6 m/s at all the above angles in a pipe 6 m long. A second technique, Capacitance Wire Mesh Sensor (WMS) developed at Forschungszentrum Rossendorf-Dresden/Germany was also present in the tests, The results for the two sensors are shown to be within 1% of each other in some instances when comparing cross-sectional averaged void fraction. The data was recorded at an acquisition frequency of 1000 Hz over an interval of 60 seconds. This enabled an examination of the flow to be carried out at several levels of complexity. Both measuring sensors provide time and cross-sectionally resolved information about the spatial distribution of the phases. In present paper, the effect of inclination on the characteristics of slug flow is presented. Radial gas volume fraction profiles and bubble size distributions were also processed from the wire-mesh sensor output. The results indicate that the pipe inclination has a significant effect on the slug flow characteristics.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Ofrecemos descuentos en todos los planes premium para autores cuyas obras están incluidas en selecciones literarias temáticas. ¡Contáctenos para obtener un código promocional único!