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SPD cooling Test bench Preliminary results CERN (Geneva) 12-01-11. Francescon Università & INFN Padova. Summary. Description of the test bench experimental setup Clean filters characterization Masked filters tests P ollution test. Why a test bench. Problems in the SPD cooling system
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SPD cooling Test benchPreliminary resultsCERN (Geneva) 12-01-11 Francescon Università & INFN Padova
Summary • Description of the test bench experimental setup • Clean filters characterization • Masked filters tests • Pollution test
Why a test bench Problems in the SPD cooling system (and related losses in detection efficiency) + Difficult theoretical evaluation of the problem = Experimental test bench
The plant The ideal plant: • Exact replica of the real plant • Many measuring points (T, p, flow) along the stave and the whole plant Temporary plant: • Similar to the real plant (smaller scale) • Many measuring points • Being upgraded for larger flow Meanwhile: We use a thermosiphon plant built by the EN/CV/DC group’’
Two-phase thermosiphon plant Condenser Chiller Dummy Load • Natural circulation of the Fluid (C4F10) • On the liquid phase by gravity • On the gas phase by pressure difference
Test bench schema PP4 filter and pressure PP3 filter and pressure
Setup characteristics • Available pressure difference (supply-return) dp= ~ 2,5 bar 2) Nominal flow ~ 3,7 g/s(without filters) 3) The sector is an exact replicaof an SPD sector from the mechanical/hydraulic point of view; The only difference is that in this case power on the sector is not generated by the detector but with a power supply (so the power can be adjusted very simply).
Filters characterization Clean 60 um filter Clean 20 um filter
Filters characterization N.B. This is the situation that we have now in the cavern: • 60 um filter in PP4 • 60 um filter in PP3 N.B. Dp is measured only on the secon filter (PP3). Two 60 um clean filters in series
Filter Dp and flow variations with the power applied to the sector 60 um clean filter 0,5 g/s decrease 100 mbar decrease
Flow variations with the power applied to the sector for different flowrate Clean 60 um filter
Bubbles formation °C bar Closing point Closing point
Bubbles formation point on the p-h diagram Liquid Liquid+Gas T=18°C P=2,13 bar Gas
Masked filters 3 different type of masked filter used (all clogged with epoxy glue): • Spot masked filter: filter clogged with 6 dot (dot diameter ~1 mm & clogged surface ~50% ) • Diffuse masked filter: filter clogged in a diffusive way (clogged surface ~50%) • Center masked filter: filter clogged in the middle part of the surface (clogged surface ~65%) Spot filter Center filter
Pollution tests 4 kind of Goodfellow calibrated metal particles: • 0,4-12 um carbon vitreous powder • 20-50 um carbon vitreous powder • 80-200 um carbon vitreous powder <75 um carbon powder • <75 um carbon powder Test procedure: 1) The powder has been introduced in the pipe upstream both filters 2) Vacumm has been made downstream both filters 3) Flow and Dp across the PP3 filter has been evaluated for different flowrate and different power applied to the sector
Powder sample Due to technical problems • Difficult handling of very small particles • Powder adehesion on the pipe wall and on the instruments • … the real amount of powder is ~50%. 0,4-12 um carbon vitreous powder0,25 g of powder
Pollution test: 0,4-12 um After the insertion of 0,25 g (nominal) of 0,4-12 um carbon vitreous powder After the insertion 0,5 g (nominal) of powder: Valve fully open PP4=2,47 bar Dp=0,355 Flow=1,155 N.B. With clean 60 um filter and clean circuit: Valve fully open PP4=3,67 bar Dp=0,48 bar Flow=3,5 g/s With epoxy glue 50% diffuse clogged filter: Valve fully open PP4=3,665 bar Dp=0,484 Flow=3,368 g/s
Pollution test: 80-200 um Stop&Start
Pollution test: 20-50 um I,II and III insertion Steps
Pollution test: <75 um I insertion III insertion Stepsteps
Pollution test: 0,4-12 um (small amount) Stop&Start Powder insertion Stop&Start with vacuum
Inserted another little amount (~ 0,05 g) of 0,4-12 um carbon powder
Conclusions • Powder clogging results to be more effective than epoxy glue clogging • Powder crossing through the PP4 filter and following deposition on PP3 filter observed • Flow variation with Stop&Start observed
Spot clogged filter: filter clogged with 6 dot (approx. diameter 1 mm & approx. clogged surface 50% )
Center clogged filter:filter clogged in the middle part of the surface (approx. clogged surface 65%)
Diffuse clogged filter:filter clogged with 6 dot (approx. diameter 1 mm & approx. clogged surface 50% )
Two portions Of 0,4-12 um carbon powder inserted in the same time (0,5 g in total) PP4 [bar]
80-200 um carbon vitreous powder0,2 g inserted in different times
20-50 um carbon vitreous powder~ 0,15 g inserted in different times
Test with a little amount (~ 0,05 g) of 0,4-12 um carbon powder