PowerPoint

Quantitative Evaluation of Void Fraction on Boiling Two-phase Flow in a Tube by Using Neutron Radiography2012/01/06-07

Seminar on neutron imaging @KURRI Quantitative evaluation of void fraction of boiling two-phase flow in a tube using neutron radiography 1. Background and objective 2. Experimental apparatus 3. Image processing method 4. Experimental result

Another experiment 1. downward flow 2. Oscillatory flow Summary IntroductionBoiling two-phase flowSingle phase liquidSlug flowAnnularflowBubbly flow

3 Radiographyf0

Neutron beamr[g/cm3] : mm [cm/g] f

Visible lightConverterMirrorCCD cameraLens

4 Radiographyf0

Neutron beamr[g/cm3] : mm [cm/g] f

Visible lightConverterMirrorCCD cameraLens

Objective5 Radiography

SGSLSTPOair onlyliquid onlytwo-phase flowoffset

Void fraction01Void fraction distribution

6

Nuclear reactorKURB4 portThermal output1 MWNeutron flux1107 n/cm2sTypical spectrum1.2 AGuide tube length11.7 mGuide tube cross section10D75D mm Nuclear ReactorB-41MW7 Imaging SystemConverter ZNSL-L100-AL1016CHICHIBU FUJI co., ltd.LensAPO MACRO 180mm F3.5SIGMA corporationCCD camera PIXIS 1024BPrinceton InstrumentsImaging array 10241024 pixels

LensCCD camera CCD cameraLensCCD8

Experimental Apparatus I.D.3mm, 5mm, 10mmG3006001000kg/m2sTin80 deg.CExperimental condition Experimental Apparatus

ToutD.P. CellElectrical InsulationElectrodeTinD.P. CellElectrical InsulationElectrode400,1000

z=010 Visible regionxzy

68.6Flame size10241024pixelpixelSpatial resolution 0.067mm/pixelExposure time20s (3mm,5mm)30s (10mm) Measurement Error

White spot noiseDUgObjectConverterNeutron sourceNeutron beamLPenumbraLf=25mm Dh Dw

Ls=4675mmUgw=0.11mm(2pixel)Ugh=0.8mm(14pixel)Dw=10mm Dh =75mm Measurement ErrorUnsharpness--13

2100I.D=5 mm Measurement ErrorDynamic range

B4C GridTest sectionConverter5331003AluminumB4C Measurement ErrorScattered neutrons100

6% Tube Wall +5%-5%

Void fractionLiquid thickness0.56%5%15

Z=370 mm

Z=210 mm

Z=150 mm Void fraction (5mm)

Void fraction0Thermal output : 1MWExposure : 20s

Electrode400

z=0

I.D.=5mm L=400mmG=600kg/m2s

Experimental result (q:const.) I.D.=5mm L=1000mmTout=156 deg.C (0.57 MPa)Tout=145 deg.C (0.43 MPa)

Tout=172 deg.C (0.8 MPa)Tout=165 deg.C (0.7 MPa).

Experimental result (q:const.) I.D.=5mm L=400mmTout=172 deg.C (0.8 MPa)Tout=165 deg.C (0.7 MPa).Tout=156 deg.C (0.57 MPa)Tout=145 deg.C (0.43 MPa) Quantitative evaluation of void fraction of boiling two-phase flow in a tube using neutron radiography 1. Background and objective 2. Experimental apparatus 3. Image processing method 4. Experimental result

Another experiment 1. downward flow 2. Oscillatory flow Summary

G=300 kg/m2s Experimental result (q:const.) I.D.=10mm L=400mm

Void fraction0Thermal output : 1MWExposure : 30sSynchronous signal-CCD

Pulse Counter

Delay Timer

CCD

Oscillator

Oscillatory flow120000200001CCDOscillatory flow

Experimental conditionst=4 s, DG/G0=1.0, q=124.8 kW/m2, xeq=0.009 Experimental result Thermal output : 5MW

Void fraction0Exposure time0.03 sAccumulation number34Accumulated exposure time1.0 s221000mm 400mm Summary