Konrad, Joachim

Krauth, Kevin

Schaub, Thomas

KITopen

KIT – The Research University in the Helmholtz AssociationINSTITUTE for NEUTRON PHYSICS and REACTOR TECHNOLOGY (INR)www.kit.eduDesign process of a vertical backward facing step experiment for forced- and mixed-convection low Prandtl number flowsThomas Schaub (INR-KIT), Kevin Krauth (TEC-KIT) & Joachim Konrad (TEC-KIT)Presented by Christine SteinerInstitute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology2 Thomas Schaub et.al.Presented by Christine Steiner04.09.2019Structure of this presentationMotivation and problems of liquid metal thermal-hydraulics: theory andexperimentsPresentation of a confined liquid metal vertical backward facing stepexperimentDesign process of the experimentPerspectives on what to expect from the experimentInstitute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology3 Thomas Schaub et.al.Presented by Christine Steiner04.09.2019Structure of this presentationMotivation and problems of liquid metal thermal-hydraulics: theory andexperimentsPresentation of a confined liquid metal vertical backward facing stepexperimentDesign process of the experimentPerspectives on what to expect from the experimentInstitute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology4 Thomas Schaub et.al.Presented by Christine Steiner04.09.2019Motivation and problems: theory & experimentsLiquid metal thermal-hydraulics „renaissance“: CSP + 𝐻2 + 𝐶Industry: accurate calculation tools for various convective regimesProblem: viscous and thermal scale dissimilarity𝑢𝑖′𝑢𝑗′ and or 𝑢𝑖′𝑇′ :minimum: algebraic modelsideal: transport equationsInstitute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology5 Thomas Schaub et.al.Presented by Christine Steiner04.09.2019Motivation and problems: theory & experimentsHighly scattered dataReasons:Instrumentation?Boundary conditionsNo-slip?Inlet?Outlet?EquationsBuoyancy? Constant properties?Literature: data available for „canonic“ turbulence cases – mix?Institute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology6 Thomas Schaub et.al.Presented by Christine Steiner04.09.2019Structure of this presentationMotivation and problems of liquid metal thermal-hydraulics: theory andexperimentsPresentation of a confined liquid metal vertical backward facing stepexperimentDesign process of the experimentPerspectives on what to expect from the experimentInstitute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology7 22.10.2019Presentation of the experimentExpansion factor: 2Aspect ratio: 2 → technical constraints!Institute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology8 22.10.2019Presentation of the experimentInstitute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology9 22.10.2019Presentation of the experimentPumpFlow conditioningHeatexchanger(cooling)Test sectionGravityFlow meters (not shown)Institute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology10Chosen liquid metal: GaInSnUser friendly liquid metalFirst step towards sodium BFS(Re-)Development of instrumentation + ad hoc data analysis methodsData: study flow characteristics for forcedand mixed convection + model validationDNS + LES already availableNiemann & Fröhlich (IJHMT + Dissertation, TU Dresden, 2016)Oder et. al. (IJHMT, 2019)22.10.2019Presentation of the experimentGravityPumpFlow conditioningHeatexchanger(cooling)Test sectionFlow meters (not shown)Institute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology11 Thomas Schaub et.al.Presented by Christine Steiner04.09.2019Structure of this presentationMotivation and problems of liquid metal thermal-hydraulics: theory andexperimentsPresentation of a confined liquid metal vertical backward facing stepexperimentDesign process of the experimentPerspectives on what to expect from the experimentInstitute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology12 22.10.2019Presentation of the experimentGravityPumpFlow conditioningHeatexchanger(cooling)Test sectionFlow meters (not shown)Institute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology13 Thomas Schaub et.al.Presented by Christine Steiner04.09.2019Design processW.K. George´s methodWhy do an experiment?Design stepsStep 1: Isolate and identify the phenomenaStep 2: Choose the right toolStep 3: Design backwardsFluid dynamicist first, then, and only then, canyou become an experimentalistInstitute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology14 Thomas Schaub et.al.Presented by Christine Steiner04.09.2019W.K. George´s methodWhy do an experiment?Design stepsStep 1: Isolate and identify the phenomenaStep 2: Choose the right toolStep 3: Design backwardsDesign processFluid dynamicist first, then, and only then, canyou become an experimentalistInstitute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology15 22.10.2019Resolution < 2x scales of interestBFS geometry + boundary conditionsFacility (+ liquid metal volume) ComponentsIdeal: backwardsDesign process – designing backwardsInstitute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology16 22.10.2019Resolution < 2x scales of interestBFS geometry + boundary conditionsFacility (+ liquid metal volume) ComponentsIdeal: backwardsDesign process – designing backwardsOur case...Institute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology17 22.10.2019Resolution < 2x scales of interestBFS geometry + boundary conditionsFacility (+ liquid metal volume) ComponentsIdeal: backwardsDesign process – designing backwardsOur case...Institute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology18 22.10.2019GaInSn very expensive → limited volumeFrom unconfined („2D“) to confined („3D“) + limited inlet and outlet lengths...Back to step 1: identify phenomenon„2D“ physics +Secondary motions of the second kind (Prandtl)Obstacle (trip wire)LES simulations are currently being performedIterative processMatch probe´s resolution to volumeMatch required Reynolds number to pumpDesign process – BFS geometry + b.c.Institute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology19 22.10.2019GaInSn very expensive → limited volumeFrom unconfined („2D“) to confined („3D“) + limited inlet and outlet lengths...Back to step 1: identify phenomenon„2D“ physics +Secondary motions of the second kind (Prandtl)Obstacle (trip wire)LES simulations are currently being performedIterative processMatch probe´s resolution to volumeMatch required Reynolds number to pumpDesign process – BFS geometry + b.c.Institute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology20 22.10.2019Resolution < 2x scales of interestBFS geometry + boundary conditionsFacility (+ liquid metal volume) ComponentsIdeal: backwardsDesign process – designing backwardsOur case...Institute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology21 22.10.2019Boundary conditions (practice, still theory)Flat velocity inlet with low 𝑇𝑢and laminar 𝛿Hydraulic design rules for airand water ~ liquid metalsDesign based on classic literature on wind tunneldesign: Bradshaw, Metha, Idel´chik, Barlow et.al. (andreferences therein) GaInSn: oxide issues → mesh size > 2 mmDesign process – BFS geometry + b.c.Measurement probesPump90° bendwith vanesWide angle Diffuser (3) Settlingchamber5:1 ContractionFlow meters(not shown)Heat exchanger(cooling)HeatingplatePressuresensorPressuresensorHole platesGravityWide angle Diffusers (1 & 2)Institute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology22 22.10.2019Boundary conditions (practice, still theory)Flat velocity inlet with low 𝑇𝑢and laminar 𝛿No slip + adiabatic wallsDesign process – BFS geometry + b.c.mechanically wet surfaces: gallium-oxides𝒌𝑮𝒂𝑰𝒏𝑺𝒏 ~ 𝒌𝑺𝑺not easy!Institute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology23 22.10.2019Boundary conditions (practice, still theory)Flat velocity inlet with low 𝑇𝑢and laminar 𝛿No slip + adiabatic wallsConstant heat fluxNo trace of heaterIsolated copper plate120 thermocouples... constant temperature?Design process – BFS geometry + b.c.Institute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology24Unfortunately, not in this caseIterative process22.10.2019Resolution < 2x scales of interestBFS geometry + boundary conditionsFacility (+ liquid metal volume) ComponentsIdeal: backwardsDesign process – designing backwardsOur case...Institute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology25 22.10.2019Design process - facilityFacility parametersExpected minimum valueExpected maximum valueComments𝑻𝒊𝒏𝒍𝒆𝒕 20°𝐶 80°𝐶 ∆𝑇𝑚𝑎𝑥=ሶ𝑞ℎ𝑘𝑟𝑒𝑓~ 30 [°𝐶]𝑹𝒆𝒉 3 800 57 000 𝑅𝑒ℎ =𝑈𝑏ℎ𝜈, 𝜈 = 𝜈(𝑇 = 25°𝐶)𝑷𝒓 0.019 0.031𝑷𝒆𝒉 128 1 900 𝑃𝑟 = 𝑃𝑟(𝑇 = 25°𝐶)𝑹𝒊𝒉 0.007 1.6 𝑅𝑖ℎ =𝑔𝛽∆𝑇ℎ𝑈𝑏2 , max. heat inputPumpFlow conditioningHeatexchanger(cooling)Test sectionGravityFlow meters (not shown)Institute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology26 22.10.2019Design process - facilityFacility parametersCurrent status: commissioningExpected minimum valueExpected maximum valueComments𝑻𝒊𝒏𝒍𝒆𝒕 20°𝐶 80°𝐶 ∆𝑇𝑚𝑎𝑥=ሶ𝑞ℎ𝑘𝑟𝑒𝑓~ 30 [°𝐶]𝑹𝒆𝒉 3 800 57 000 𝑅𝑒ℎ =𝑈𝑏ℎ𝜈, 𝜈 = 𝜈(𝑇 = 25°𝐶)𝑷𝒓 0.019 0.031𝑷𝒆𝒉 128 1 900 𝑃𝑟 = 𝑃𝑟(𝑇 = 25°𝐶)𝑹𝒊𝒉 0.007 1.6 𝑅𝑖ℎ =𝑔𝛽∆𝑇ℎ𝑈𝑏2 , max. heat inputInstitute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology27 Thomas Schaub et.al.Presented by Christine Steiner04.09.2019Structure of this presentationMotivation and problems of liquid metal thermal-hydraulics: theory andexperimentsPresentation of a confined liquid metal vertical backward facing stepexperimentDesign process of the experimentPerspectives on what to expect from the experimentInstitute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology28 Thomas Schaub et.al.Presented by Christine Steiner04.09.2019Perspectives on what to expectWhat we can measure𝑢𝑖 = 𝑢𝑖 + 𝒖′T = 𝑇 + 𝑻′𝒖𝒊′𝑻′Spectral characterization of convective regimes?Important!When using and analysing data → viscosity must be assumedtemperature-dependantResult from similar analysis as Gray & Giorgini (1976) for air and water, but on GaInSn → sodium as well!Institute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology29 Thomas Schaub et.al.Presented by Christine Steiner04.09.2019Summary: take away messagesLiquid metal thermal-hydraulics: challenging in both theory and practiceA confined vertical backward facing step experiment is going to beperfomed at KIT soonDesign process based on W.K. George´s method + experience from past experimentsSpecial efforts were put into generating reproducible and measurableboundary conditions: inlet, outlet, walls, heat inputPreliminary results by winter 2019/2020 – final results expected forspring 2020Institute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology30 Thomas Schaub et.al.Presented by Christine Steiner04.09.2019AppendixInstitute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology31 Thomas Schaub et.al.Presented by Christine Steiner04.09.2019AppendixInstitute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology32 22.10.2019𝑈𝑏𝑈𝑏𝑉𝑏Jet flow Plane mixing layerInstrumentation? AppendixInstitute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology33 22.10.2019No! Flow conditioning. AppendixInstitute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology34 Thomas Schaub et.al.Presented by Christine Steiner04.09.2019Permanent magnet probes𝑢𝑖 → Faraday + Ohm (MHD) T → SeebeckWhat can measure?𝑢 = 𝑢 + 𝒖′T = 𝑇 + 𝑻′𝒖′𝑻′Very challenging measurement chain + few drawbacksHighly sensitive devices (external noise)Very low voltages (nanovolt range) → Peltier + Johnson + Thomson matter!Invasive + miniaturization restricted BUT „perfect“ signal transfer functionAppendix𝒖𝑬𝑩∅𝟐. 𝟓 𝒎𝒎 > ∅𝟏. 𝟔 𝒎𝒎Institute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology35 22.10.2019AppendixPumpFlow conditioningHeatexchanger(cooling)Test sectionGravityInstitute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology36 22.10.2019AppendixPumpFlow conditioningHeatexchanger(cooling)Test sectionGravityInstitute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology37 22.10.2019AppendixPumpFlow conditioningHeatexchanger(cooling)Test sectionGravityInstitute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology38 22.10.2019AppendixPumpFlow conditioningHeatexchanger(cooling)Test sectionGravityInstitute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology39 22.10.2019AppendixPumpFlow conditioningHeatexchanger(cooling)Test sectionGravityInstitute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology40 22.10.2019AppendixPumpFlow conditioningHeatexchanger(cooling)Test sectionGravityInstitute for Neutron Physics and Reactor TechnologiesKarlsruhe Institute of Technology41 22.10.2019AppendixPumpFlow conditioningHeatexchanger(cooling)Test sectionGravity

Design process of a vertical backward facing step experiment for forced- and mixed convection low prandtl number flows

https://publikationen.bibliothek.kit.edu/1000099201/45112070

Design process of a vertical backward facing step experiment for forced- and mixed convection low prandtl number flows

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