Bechta, S.

Cron, T.

Fluhrer, B.

Gaus-Liu, X.

Komlev, A.

Ma, W.

English

KITopen

International Seminar IVMR‐2020 – Juan‐les‐PinsExperiments on Thermohydraulics ofStratified Melt Pool –SIMECO‐II and LIVE2D TestsX. Gaus‐Liu, T. Cron, B. Fluhrer  (KIT)A. Komlev, W. Ma, S. Bechta (KTH)January 21‐23, 2020International Seminar IVMR‐2020 – Juan‐les‐PinsOutline• Objectives• Experimental setups– SIMECO‐II– LIVE2D• Performance of LIVE2D test series• Results of LIVE2D test series• Summary and Outlook2International Seminar IVMR‐2020 – Juan‐les‐PinsObjectives3• In‐vessel melt retention by external cooling• High risk of thermal load on the vessel wall in the metallic layer due to the heat flux focusing effect influenced by:• Interlayer crust • Upper layer thickness• Upper boundary cooling conditionObjectives??????International Seminar IVMR‐2020 – Juan‐les‐PinsExperimental Setup – SIMECO‐II facility4International Seminar IVMR‐2020 – Juan‐les‐PinsLIVE2D Experimental Setup 5• Slice geometry:1 m in diameter, 12 cm in width,• Transparent front wall and insulated back wall,• Nine layers of evenly distributed electrical heating cables in the vessel,• External boundary rigid cooled; upper surface either rigid cooled or under hot air atmosphere.International Seminar IVMR‐2020 – Juan‐les‐PinsPerformance of LIVE2D test series6TestSimulant material Heigh of layer, mmHeating phase, WBoundary condition Upper layerLower layerUpper layerLower layerheating only in lowerlayerTop surface Vessel wallSO1Thermal oileutecticNaKNO335 3401300 – 940 – 1040 –1310 – 1400 – 900 Hot air (metal plate covers the vessel)Water cooled75 340 1300 – 1800‐ 1150110 3402200 – 1800 – 1400 –160075 340 1600SOTCThermal oileutecticNaKNO3110  3403000 – 3600 ‐ 4250Rigid cooling (Water cooled lid)Water cooled753754230 – 3000 ‐ 360035 4153600 – 3000 – 4300 –3400 –2400 – 1800International Seminar IVMR‐2020 – Juan‐les‐PinsMaterial properties in LIVE2D tests7Material properties unit Lower layer:50% KNO3‐50% NaNO3Upper layer:Thermal oilat 224 °C at 260 °C at 140 °C at 220 °Cdensity kg/m³ 1964 1937 755 540kinematic viscosity mm²/s  2.76 2.23 11 9thermal conductivity W/(mK) 0.48 0.47 0.15 0.15thermal capacity J/(gK) 1.29 1.31 1.7 1.83Pr 14.5 12.0 94 59International Seminar IVMR‐2020 – Juan‐les‐PinsLIVE2D test interlayer crust behaviour8Compact crustAlmost no crustHalf crust International Seminar IVMR‐2020 – Juan‐les‐PinsResult ‐ Transient process in SO1 test90.04.447.171.095.0100.5Upper layer0mm Upper layer35mmUpper layer75mmUpper layer110mmUpper layer75mm020406080100120140160180200220240260280300-150mm-100mm-50mm100mmtime, hourmelt temperature, °Cheight to the layer interface at 340mm:in upper layer:  85mm  50mm  0mmin lower layer  -50mm  -100mm  -150mm0mm50mmInternational Seminar IVMR‐2020 – Juan‐les‐PinsLIVE2D Results ‐ upper layer melt flow patternSO1 test: hot atmosphere at the upper surface: global circulation10International Seminar IVMR‐2020 – Juan‐les‐Pins 11SOTC  test: rigid cooled upper surface. Raleigh‐Bernard convectionInternational Seminar IVMR‐2020 – Juan‐les‐PinsResults ‐ Upper layer temperature profiles in SO1 test12020406080100120140 160 180 200 220 240height in oil layer, mmtemperature, °C110 mm layer, 2200 WR=4mmR=229mmR=390mm0510152025303540140 160 180 200 220 240height in oil layer, mmtemperature, °C35 mm layer, 1400 WR=4mmR=229mmR=339mm01020304050607080140 160 180 200 220 240height in oil layer, mmtemperature, °C75 mm layer, 1600 WR= 4 mmR= 229 mmR= 390mmInternational Seminar IVMR‐2020 – Juan‐les‐PinsResults ‐ LIVE2D Heat fluxes (1)13050001000015000200000 20 40 60 80 100heat flux, W/m²polar angle, °upper layer 112mm4.3kW3.6kW3kWinterface05000100001500020000250000 10 20 30 40 50 60 70 80 90heat flux, W/m²polar angle, °upper layer 37mm3.6kW 3kW4.3kW 3.4kW2.4kW 1.8kWinterface050001000015000200000 10 20 30 40 50 60 70 80heat flux, W/m²polar angle, °upper layer 35mm0.9kW 0.94kW1.08kW 1.13kW1.31kW 1.4kWinterface050001000015000200000 20 40 60 80 100heat flux, W/m²polar angle, °upper layer 110mm1.4kW 1.6kW1.8kW 2.2kWinterfaceSO1 test: hot atmosphere at the upper surfaceSOTC  test: rigid cooled upper surfaceInternational Seminar IVMR‐2020 – Juan‐les‐Pins 14Results ‐ Heat flux focusing effect0200040006000800010000120001400016000180002000040 60 80 100 120 140 160heat flux, W/m²heat source density, kW/m³Upper layer sidewall heat fluxSO1, q_up, max SOTC, q_up, max.SO1, q_up, av. SOTC, q_up, av.0,00,51,01,52,02,53,03,54,04,55,040 60 80 100 120 140 160up/down sidewall  heat flux ratioheat source density, kW/m³up/ down sidewall heat flux ratio(here: heat flux focusing factor)SO1, q_up, av. / q_dn, avSO1, q_up, max. / q_dn, maxSOTC, q_up, av. / q_dn, avSOTC, q_up, max. / q_dn, max• Heat flux focusing factor reduces strongly under rigid surface cooling,• Heat flux focusing factor decreases gradually when the interlayer crust melts down and the layer interface temperature increases.International Seminar IVMR‐2020 – Juan‐les‐PinsChurchill&Chu correlation and boundary conditionsLaminar flow, Ra<109	 , 0.680.671 0.492Turbulent Flow: Ra>1090.8250.3871 0.492Pr 	/15Results ‐ Nu and Ra of the upper layer sidewall heattransfer (theory)• ,• ,•• 	 , ,Reference Temperauture of parameter isTfilm : (Tbulk + T w, up) /2~~• Isothermal heated plate• Upward flow• Non‐confined cavity• For all Pr valuesUpper layer boundary conditions in Corium poolStrong heatingWeek coolingStrong cooling• Downward flow on cooled vertical plate• confined cavity with heated bottom boundaryInternational Seminar IVMR‐2020 – Juan‐les‐Pins 16Results ‐ Nu and Ra in LIVE2D testsNusd =  0.0282 Rasd 0.35R² = 0.9450501001502002503001,E+07 1,E+08 1,E+09 1,E+10Nu sdRa sdChurchill&Chu turbulent flowChurchill&Chu laminar flowSO1SOTCInternational Seminar IVMR‐2020 – Juan‐les‐Pins 17Heat Balance in LIVE2D tests0.04.447.171.095.0100.5Upper layer 0mmUpper layer 35mmUpper layer 75mmUpper layer 110mmUpper layer 75mm0100020003000Qwall upperQwall lowertime, hourpower/heat transfer rate, Wpower inputQwall totalSO1 testQwall /Q in ~ 0.37‐0.46Main heat losses via • Front wall (radiation)• Cooled sidewall above the melt • Hot air above the melt SOTC test• Qwall /Q in ~ 0.21‐0.31• Waterside heat transfer measurements at the sidewall and at the upper surface were not reliable due to the low water pressure and low flow rate.024.3749.8293.63Upperlayer112mm Upperlayer77mm Upperlayer37mm0100020003000400050006000power inputQ upper surfacepower, heat transfer rate, WTime, hourQ wall totalInternational Seminar IVMR‐2020 – Juan‐les‐Pins• SIMECO‐II and LIVE2D test facilities were designed for the thermal hydraulic studies of a stratified melt pool in large geometry,• SIMECO‐II test will apply metallic simulant material in the upper layer, whereas LIVE2D applied thermal oil for the upper melt layer,• Two series of LIVE2D test with 3 upper‐layer thicknesses were performed,• The transient process of the upper layer is longer than that of the lower layer, and it reflects the time period of interlayer crust change,• Strong heat flux focusing effect was observed when the heat transfer at the melt upper surface was poor; whereas upper surface rigid cooling can effectively minimize the heat flux focusing effect,• The experimental results of Nu of upper layer sidewall heat transfer is considerably lower than the Churchill & Chu correlations. 18SummaryInternational Seminar IVMR‐2020 – Juan‐les‐Pins• SIMECO‐II plans?19OutlookInternational Seminar IVMR‐2020 – Juan‐les‐PinsThis work is funded by the IVMR grant agreement number 662157 (H2020) and national governments 20

Experiments on Thermohydraulics of Stratified Melt Pool – SIMECO‐II and LIVE2D Tests

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Experiments on Thermohydraulics of Stratified Melt Pool – SIMECO‐II and LIVE2D Tests

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