References of "Leyer, Stephan 50003662"
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See detailPrevention of Electrostatic Charge Generation in Filtration of Low-Conductivity Oils by Surface Modification of Modern Filter Media
Staudt, Johannes; Duchowski, Johan; Leyer, Stephan UL

in Tribology Transactions (2020)

The electrostatic charging behavior of filter elements operating in various hydraulic and lubricating fluids has been re-examined from the perspective of fundamental material properties of the two ... [more ▼]

The electrostatic charging behavior of filter elements operating in various hydraulic and lubricating fluids has been re-examined from the perspective of fundamental material properties of the two materials participating in the event. In contrast to the previously proposed mechanisms that focused predominantly on fluid and material conductivities, new evidence strongly suggests that the relative placement of the substrates in the triboelectric series must be taken into account. The positions occupied in the triboelectric series account for the donor/acceptor tendencies exhibited by the materials when brought close together in close proximity ( 10 nm). Nevertheless, this behavior is only an outward manifestation of the deeper underlying characteristics that include material surface energies and, looking even deeper, the associated electron work functions of the interacting materials. Herein we provide several examples of the enhanced understanding of the electrostatic charging/discharging (ESC/ESD) phenomena as they occur in the course of filtration of hydraulic and lubricating fluids through modern filter elements constructed of synthetic glass fiber and polymer materials. [less ▲]

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See detailModelling of Passive Heat Removal Systems: A Review with Reference to the Framatome BWR Reactor KERENA: Part II
Manthey, René; Viereckl, Frances; Moonesi Shabestary, Amirhosein et al

in Energies (2019)

Passive safety systems are an important feature of currently designed and constructed nuclear power plants. They operate independent of external power supply and manual interventions and are solely driven ... [more ▼]

Passive safety systems are an important feature of currently designed and constructed nuclear power plants. They operate independent of external power supply and manual interventions and are solely driven by thermal gradients and gravitational force. This brings up new needs for performance and reliably assessment. This paper provides a review on fundamental approaches to model and analyze the performance of passive heat removal systems exemplified for the passive heat removal chain of the KERENA boiling water reactor concept developed by Framatome. We discuss modeling concepts for one-dimensional system codes such as ATHLET, RELAP and TRACE and furthermore for computational fluid dynamics codes. Part I dealt with numerical and experimental methods for modeling of condensation inside the emergency condenser and on the containment cooling condenser. This second part deals with boiling and two-phase flow instabilities. [less ▲]

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See detailModelling of Passive Heat Removal Systems: A Review with Reference to the Framatome KERENA BWR Reactor: Part I
Moonesi Shabestary, Amirhossein; Viereckl, Frances; Zhang, Yu et al

in Energies (2019)

Passive safety systems are an important feature of currently designed and constructed nuclear power plants. They operate independent of external power supply and manual interventionsand are solely driven ... [more ▼]

Passive safety systems are an important feature of currently designed and constructed nuclear power plants. They operate independent of external power supply and manual interventionsand are solely driven by thermal gradients and gravitational force. This brings up new needs forperformance and reliably assessment. This paper provides a review on fundamental approaches to model and analyze the performance of passive heat removal systems exemplified for the passive heat removal chain of the KERENA boiling water reactor concept developed by Framatome. We discuss modelling concepts for one-dimensional system codes such as ATHLET, RELAP and TRACE and furthermore for computational fluid dynamics codes. Part I deals with numerical and experimental methods for modelling of condensation inside the emergency condensers and on the containment cooling condenser while part II deals with boiling and two-phase flow instabilities. [less ▲]

Detailed reference viewed: 38 (8 UL)
See detailPANAS- Project: Heat Transfer Model Development for Passive Safety Systems,
Leyer, Stephan UL; Hampel; Schuster, C et al

in NURETH-18 (2019, August 18)

Detailed reference viewed: 28 (1 UL)
See detailLuxCube the First CubeSat Student Satellite in Luxembourg
Rabbadan Santana, E; Weiss, T; Djordjevic, A et al

Poster (2019, June 15)

Detailed reference viewed: 20 (1 UL)
See detailEvaluation of Stratified Condensation Models for a slightly inclined tube unsing ATHELT Code
Zhang, Yu; Moonesi Shabestary, Amir Hossein; Bieberle, Andre et al

in NURETH-18 (2019)

Detailed reference viewed: 35 (7 UL)
See detailInvestigation of Thermal Coupling in Condensation Process at COSMEA Facility with ATHLET Code
Zhang, Yu; Leyer, Stephan UL; Hampel, U

in Reactor engineering (2018, October)

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See detailAn investigation of condensation process at COSMEA test facility with ATHLET code
Zhang, Yu UL; Geißler, Thomas; Leyer, Stephan UL et al

in Kerntechnik (2018), 83(3), 208-214

Safety is an essential topic in the development process of nuclear power plant. Several Generation III and III+ reactor designs contain passive safety system to control accident without external power. An ... [more ▼]

Safety is an essential topic in the development process of nuclear power plant. Several Generation III and III+ reactor designs contain passive safety system to control accident without external power. An example is the Emergency Condenser (EC) of the KERENA reactor design. The EC removes heat from the Reactor Pressure Vessel in the case of design accidents. The experimental facility COSMEA at Helmhotz Zentrum Dresden Rossendorf (HZDR) was set up to investigate the flow morphology and heat transfer structure of condensation inside a slightly inclined tube. In this paper, the condensation process in COSMEA was simulated with the thermal hydraulic system codes ATHLET. The performance of the ATHLET heat transfer models were identified. The simulation results were compared against the experiments. The heat flux, condensation rate and temperature of cooling water during the condensation was analyzed. [less ▲]

Detailed reference viewed: 54 (4 UL)
Peer Reviewed
See detailCFD Simulations of Adiabatic Boiling in Different Riser Geometries
Haag, M; Leyer, Stephan UL

Poster (2018)

Detailed reference viewed: 20 (2 UL)
See detailSimulation of condensation in a inclined tube with ATHLET code
Zhang, Yu UL; Leyer, Stephan UL

Presentation (2017, September 13)

Detailed reference viewed: 46 (0 UL)
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See detailSIMULATION OF CONDENSATION IN A SLIGHTLY INCLINED TUBE AT COSMEA FACILITY WITH ATHLET CODE
Zhang, Yu UL; Geißler, Thomas; Leyer, Stephan UL et al

Scientific Conference (2017, September 06)

Safety is an essential topic in the development process of nuclear power plant. Several Generation III reactor designs contain passive safety system to control accident without the need for external power ... [more ▼]

Safety is an essential topic in the development process of nuclear power plant. Several Generation III reactor designs contain passive safety system to control accident without the need for external power supply. An example for such passive systems is the Emergency Condenser (EC) of the KERENA reactor design. The system removes heat from the Reactor Pressure Vessel in the case of design basis accidents. The experimental facility COSMEA at Helmhotz Zentrum Dresden Rossendorf (HZDR) was set up to investigate the flow morphology and heat transfer structure of condensation processes. The test rig consists of a 3 m long condenser pipe which is 0.76° inclined with inner diameter 43.3 mm. On the shell side active cooling is performed using the TOPFLOW facility infrastructure. According to the Emergency Condenser Reference design, the experiments of COSMEA are conducted in different pressure levels (5, 15, 25, 45 and 65 bar) with steam mass flow rates up to 1 kg/s. An inlet mixing system was developed to operate the experiment in a stepwise method due to the scale of the test rig. Condensation rates, pressure, temperature and flow rate for different steam fraction are measured. In addition, an x-ray tomography is installed to study the details of the resulting stratified flow structures. Extra heat flux probes are assembled to detect the azimuthal distribution of the heat flux. In this work, COSMEA was simulated the thermal hydraulic system codes ATHLET. The performance of the ATHLET heat transfer models were identified. Primarily, the steady-state model was developed and the simulation results were compared to the experiment. The thermal coupling which considers the heat exchange between outside and inside of the pipe during the condensation was analyzed. Posteriorly the case of modeling transient condensation process was simulated. The influence on thermal coupling parameters, particularly heat transfer coefficient due to pressure drop inside the pipe was predicted and the feasibility and limitation of the system codes were evaluated. [less ▲]

Detailed reference viewed: 24 (0 UL)
See detailPraktische Handhabung und Kunst der Modellwahl
Unger, Jochem; Leyer, Stephan UL

in Dimensionshomogenität (2015)

Detailed reference viewed: 113 (3 UL)
See detailFull scale BWR containment loca response test at the INKA test facility
Wagner, T.; Leyer, Stephan UL

in International Conference on Nuclear Engineering, Proceedings, ICONE (2015), 2015-January

KERENA is an innovative boiling water reactor concept with passive safety systems (Generation III+) of AREVA. The reactor is an evolutionary design of operating BWRs (Generation II). In order to verify ... [more ▼]

KERENA is an innovative boiling water reactor concept with passive safety systems (Generation III+) of AREVA. The reactor is an evolutionary design of operating BWRs (Generation II). In order to verify the functionality and performance of the KERENA safety concept required for the transient and accident management, the test facility "Integral Teststand Karlstein" (INKA) was built at Karlstein (Germany). It is a mock-up of the KERENA boiling water reactor containment, with integrated pressure suppression system. The complete chain of passive safety components is available. The passive components and the levels are represented in full scale. The volume scaling of the containment compartments is approximately 1:24. The reactor pressure vessel (RPV) is simulated via the steam accumulator of the Karlstein Large Valve Test Facility. This vessel provides an energy storage capacity of approximately 1/6 of the KERENA RPV and is supplied by a Benson boiler with a thermal power of 22 MW. With respect to the available power supply, the containment- and system-sizing of the facility is by far the largest one of its kind worldwide. From 2009 to 2012, several single component tests were conducted (Emergency Condenser, Containment Cooling Condenser, Core Flooding System etc.). On March 21st, 2013, the worldwide first large-scale only passively managed integral accident test of a boiling water reactor was simulated at INKA. The integral test measured the combined response of the KERENA passive safety systems to the postulated initiating event was the "Main Steam Line Break" (MSLB) inside the Containment with decay heat simulation. The results of the performed integral test (MSLB) showed that the passive safety systems alone are capable to bring the plant to stable conditions meeting all required safety targets with sufficient margins. Therefore the test verified the function of those components and the interplay between them as response to an anticipated accident scenario. The test provided evidence that the INKA is worldwide the first large scale test facility to perform integral verification tests of passive safety concepts under plant-like scaling and thermodynamic conditions. Hence, the test facility also shows that it is capable to perform containment response tests for existing Generation II BWRs (with active safety systems) and advanced (passive) reactor designs besides KERENA. These test results can be used to strengthen existing containment codes with regard to heat transfer, natural circulation, gas- and temperature stratification and others. Copyright © 2015 by JSME. [less ▲]

Detailed reference viewed: 210 (13 UL)
See detailNaturkonstanten
Unger, Jochem; Leyer, Stephan UL

in Dimensionshomogenität (2015)

Detailed reference viewed: 60 (3 UL)
See detailEffizienz der Pi Theorem Methodik
Unger, Jochem; Leyer, Stephan UL

in Dimensionshomogenität (2015)

Detailed reference viewed: 55 (2 UL)
See detailAllometrie
Unger, Jochem; Leyer, Stephan UL

in Dimensionshomogenität (2015)

Detailed reference viewed: 38 (3 UL)
See detailDimensionshomogenität: Erkenntnis ohne Wissen?
Unger, Jochem; Leyer, Stephan UL

Book published by Springer-Verlag (2015)

Detailed reference viewed: 114 (4 UL)
See detailMonetär-technologisches Wechselspiel
Unger, Jochem; Leyer, Stephan UL

in Dimensionshomogenität (2015)

Detailed reference viewed: 73 (0 UL)
See detailPi-Theorem
Unger, Jochem; Leyer, Stephan UL

in Dimensionshomogenität (2015)

Detailed reference viewed: 69 (2 UL)