Bruzzese, C.

Class, A.

Lang, F.

Schroer, C.

Weisenburger, A.

English

KITopen

KIT – Universität des Landes Baden-Württemberg undnationales Forschungszentrum in der Helmholtz-Gemeinschaft www.kit.edu4343,43,,)(4OFeandoxygenofweightmolecularMMscaleoxideofdensityscaleoxideofthicknesscladdingofsurfacetotalFoxidationoxygenofweightwtMMFwtOFeooxBBBoOFeoBoxBBo0 5000 10000 15000 20000 25000020406080100 480 °C 550 °C 450 °C 420 °C oxide scale thickness [µm]time [h]T91 at different temperatures10-6 wt%Pb 500°CPbBi  10-8  450°C    300°CC. Bruzzese, A. Weisenburger, A. Class, C. Schroer – KITMini-Pool Reactor to determine interaction and mass transport of oxygen and other impurities in flowing LBE  Design and Design supporting CFD calculationsInstitut für Hochleistungsimpuls-und Mikrowellentechnik (IHM)2 IWSMT 11 – Gent  November 5th – 9th 2012OutlineIntroductionQuestions addressed – Experiments foreseen - Pre-design Design oriented CFDSummary and next stepsInstitut für Hochleistungsimpuls-und Mikrowellentechnik (IHM)3 IWSMT 11 – Gent  November 5th – 9th 2012Oxygen – Why relevant for Pb alloy cooled ADS?Solubility of metals in liquid Pb PbBi - W, Ta<<Fe, Cr<Al<NiTo ensure compatibility of steels – formation of oxide scalesThis requires oxygen in the liquid Pb PbBi Oxygen controlOxygen level needs to be controlled to avoidPbO formationLiquid Metal corrosionOpen issues:Oxygen transport and interaction in liquid Pb PbBi – convection vs. DiffusionOxygen transport via Gas – liquid metal interfaceSolid (oxides, metals) transport and interactionWater leakage – oxygen content?350 400 450 500 550 600 650 700 750-9-8-7-6-5-4-3-2-101solubility logS (wt%)Temperature (°C) Pb           PbBi N     Cr    Fe    Al     Solubility of steel elements in Pb / PbBidiffusi  barrier for Cations!Oxide scale on the steel surfaceprevent the dissolutionliquid metalsteelT1aXT1T2aXT2T1 > T2aXT1 > aLM > aXT2oxide scaleoxide scale100 200 300 400 500 600 70010-1410-1210-1010-810-610-410-2TmaxTmeltLiquid metal corrosionCO(Fe3O4)COSOxygen concentration in Pb/Bi [wt%]Temperature [°C]LBE-OxidationPbBiPbSevere dissolution ofalloying elements (Ni)dissolution rate up to 1 µm/haustenitic steel / 1.4970Institut für Hochleistungsimpuls-und Mikrowellentechnik (IHM)4 IWSMT 11 – Gent  November 5th – 9th 2012Modular Mini-Reactor Pool for Corrosion, Mass Transport and Filtering Experimental test cases• Normal operating conditions: referencecover gas environment• Cover gas leak & gas/solid entrainment• HEX-leak (water vapour)• THEADES crud & filtering• Sacrificial Nickel probe• Filter performanceCFD Studies• Thermohydraulic characterisation• Mass transport & sources• Influence of environment gas &solid oxidesMedium T Sacrificial NiprobeHot sectionInstitut für Hochleistungsimpuls-und Mikrowellentechnik (IHM)5 IWSMT 11 – Gent  November 5th – 9th 2012Instrumentation:Oxygen sensors with thermocouplesCold probeUltrasound dopplerfloating gauge - local level (pressure, velocity)Level sensorHX-leak (water vapour)Entrainment of oxidesSacrificial Nickel probeModular Mini Reactor PoolInstitut für Hochleistungsimpuls-und Mikrowellentechnik (IHM)6 IWSMT 11 – Gent  November 5th – 9th 2012Modular Mini Reactor Pool – 1st design changesNow - 3 pots:ConditioningExperimentalHot - Sacrifcial NiInstitut für Hochleistungsimpuls-und Mikrowellentechnik (IHM)7 IWSMT 11 – Gent  November 5th – 9th 20121st Design PhaseHeating system is designed – all „pots“ aremanufactured6KW total heating powerTemperature up to 650°CInstitut für Hochleistungsimpuls-und Mikrowellentechnik (IHM)8 IWSMT 11 – Gent  November 5th – 9th 2012Design-supporting CFDAim: Support the design  - location of sensors and internalEvaluation of design based on fluid mechanical aspectsIdentification of main flow patterns & regimesAdopted strategy: Force asymmetry of flow field with choice of geometry and boundaryconditions (do not rely on existence of large scale symmetry of flow field)Flow field should contain regions withStrongly directed, fast flow mainly/definite convective transportStagnant flow, dead water regions mainly/definite diffusive transportCFD-Software: STAR-CCM+ 6 (CD-adapco) 1st stepInstitut für Hochleistungsimpuls-und Mikrowellentechnik (IHM)9 IWSMT 11 – Gent  November 5th – 9th 2012“CFD-Geometry” of main pool/tank, T=400°COutletInlet, 0.1 m/sSlip WallSpatial region of axial impeller & flow straightener, not part of computational domain3 radial orifices, d = 2 cm H=27 cmD = 30 cmd = 5 cm1st stepInstitut für Hochleistungsimpuls-und Mikrowellentechnik (IHM)10 IWSMT 11 – Gent  November 5th – 9th 2012Main pool with auxiliary heated tank (sacrificial Ni at 600°C)Bottom and side walls heated, T=600°C H=27 cmD = 13.5 cmConnection pipes, d = 10 mm1st stepInstitut für Hochleistungsimpuls-und Mikrowellentechnik (IHM)11 IWSMT 11 – Gent  November 5th – 9th 2012Numerical SettingsFinite-Volume Spatial DiscretizationPolyhedral meshStationary solverSegregated flow model, pressure-velocity coupling by SIMPLE methodConvection scheme: 2nd order upwindFluid: LBE with constant fluid properties at T=400°CReynolds-Averaged Navier-Stokes Equations (RANS)Incompressible, Buoyancy accounted for by Boussinesq approximationRealizable two-layer k-epsilon turbulence model1st stepInstitut für Hochleistungsimpuls-und Mikrowellentechnik (IHM)12 IWSMT 11 – Gent  November 5th – 9th 2012Results with auxiliary heated tank @ T=600°CMean flow velocity in connection pipes approx. 0.14 m/sFlow direction according to natural convection loopLow flow velocity in heated tankCore of large scale vortex in similar position as in simulation without heated tank1st stepInstitut für Hochleistungsimpuls-und Mikrowellentechnik (IHM)13 IWSMT 11 – Gent  November 5th – 9th 2012Main Flow Patterns, T=400°C: Core of Large-Scale VortexOnly cells with velocity magnitude < 5 mm/s are shownStable large – scale vortexPossible position of oxygen sensor (for dead zone)Stable assymetric flow pattern1st stepInstitut für Hochleistungsimpuls-und Mikrowellentechnik (IHM)14 IWSMT 11 – Gent  November 5th – 9th 2012Main Flow Patterns, T=400°C: Fast Jets from OrificesStable flow jetsTo be used for velocity measurementoxygen sensors along flow jet1 in stable dead zone (might be supported by design)1st stepInstitut für Hochleistungsimpuls-und Mikrowellentechnik (IHM)15 IWSMT 11 – Gent  November 5th – 9th 2012Design-supporting CFD – 2nd stepAim: Support the design byEvaluation of design based on fluid mechanical aspectsIdentification of main flow patterns & regimesChoice of location of sensors (concentration & velocity) and internalsAdopted strategies: Force asymmetry of flow field with choice of geometry and boundaryconditions (do not rely on existence of a large scale symmetry)Realize properly defined boundary conditionsFlow field should contain regions withStrongly directed, fast flow mainly/definite convective transportStagnant flow, dead water region mainly/definite diffusive transportCFD-Software: STAR-CCM+ 6 (CD-adapco) Institut für Hochleistungsimpuls-und Mikrowellentechnik (IHM)16 IWSMT 11 – Gent  November 5th – 9th 2012“CFD-Geometry” of main pool/tank, T=400°COutletInlet,U=0.05 m/s,Turb. Int. = 20%,Turb. Length Scale = 2mmSlip WallSpatial region of axial impeller & flow straightener, not simulated3 radial orifices, d = 2 cm H=27 cmD = 30 cmd = 5 cmconcentration sensors Quasi-stagnant flow region separated from main flow: Diffusive transport of dissolved species/gasInstitut für Hochleistungsimpuls-und Mikrowellentechnik (IHM)17 IWSMT 11 – Gent  November 5th – 9th 2012Numerical Settings – no changes Finite-Volume Spatial DiscretizationPolyhedral meshStationary solverSegregated flow model, pressure-velocity coupling by SIMPLEConvection scheme: 2nd order upwindFluid: LBE with constant fluid properties at T=400°CReynolds-Averaged Navier-Stokes Equations (RANS)IncompressibleRealizable two-layer k-epsilon turbulence modelInstitut für Hochleistungsimpuls-und Mikrowellentechnik (IHM)18 IWSMT 11 – Gent  November 5th – 9th 2012Exemplary computational mesh680,000 polyhedral cellsInstitut für Hochleistungsimpuls-und Mikrowellentechnik (IHM)19 IWSMT 11 – Gent  November 5th – 9th 2012Main Flow Patterns, T=400°C: Stable Large-Scale Low-Flow-Speed regionOnly cells with velocity magnitude < 4 mm/s are shown (4mm/s is ~10% of characteristic circumferential speed, the max. flow speed in the jets is ~ 150 mm/s)No significant change byoxygen sensorsStable stagnant regionrealized by designInstitut für Hochleistungsimpuls-und Mikrowellentechnik (IHM)20 IWSMT 11 – Gent  November 5th – 9th 2012Main Flow Patterns, T=400°C: Fast jets from orifices2 oxygen sensors in jets1 oxygen sensor in dead water pocket1 oxygen sensor in core of global low-speed region1 oxygen sensor in circumferential flowInstitut für Hochleistungsimpuls-und Mikrowellentechnik (IHM)21 IWSMT 11 – Gent  November 5th – 9th 2012Main Flow Patterns, T=400°C: Large scale circumferential flow structureStable circumferential flow patternImportant for experimentsoxygen transportFlow measurementetc.Institut für Hochleistungsimpuls-und Mikrowellentechnik (IHM)22 IWSMT 11 – Gent  November 5th – 9th 2012Main Flow Patterns, T=400°C: Location of measurement lines of flow velocity by Ultrasonic Doppler Velocimetry UDV Location of measurement line chosen according to following criteria:• upwardly inclined direction (allowing escape of air bubbles)• identification of a) main circumferential flow velocity, direction is know b) low speed region, c) fast jeta)b)c)A BABa)b)c)Institut für Hochleistungsimpuls-und Mikrowellentechnik (IHM)23 IWSMT 11 – Gent  November 5th – 9th 2012Summary and next stepsPre-design ready - pots are manufacturedCFD results in location of sensors and 1st design details„Internals“ can now be constructedNext design relevant CFD calculations:Characterization of impeller and flow straightener: homogenity of flow, turbulence intensity, turbulent length scaleCharacterization of flow around oxygen sensors(turbulent vortex street?)Unsteady simulations with time-resolved transport of dissolved speciesfrom cover gas atmosphereSimulations including all internals and auxiliary hot tank with sacrificialNi probeInstitut für Hochleistungsimpuls-und Mikrowellentechnik (IHM)24 IWSMT 11 – Gent  November 5th – 9th 2012Thanks to my colleagues at KIT C. Bruzzese – who did all the CFD calculations and prepared most of the slides,A. Class, C. Schroer , F. LangAnd to the support of the SEARCH FP7 Project - 295736

Mini-pool reactor to determine interaction and mass transport of oxygen and other impurities in flowing LBE. Design and design supporting CFD calculations

https://publikationen.bibliothek.kit.edu/230089702/3816224

Mini-pool reactor to determine interaction and mass transport of oxygen and other impurities in flowing LBE. Design and design supporting CFD calculations

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