JCOV, 25 OCT 2001 Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

ATLAS Inner Detector layoutATLAS Inner Detector layout Specifications for thermal screensSpecifications for thermal screens ANSYS simulationsANSYS simulations Prototyping and tests resultsPrototyping and tests results VerificationsVerifications

JCOV, 25 OCT 2001 Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

General view of the ATLAS Inner Detector General view of the ATLAS Inner Detector layoutlayout

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JCOV, 25 OCT 2001 Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

Heat loads in the ATLAS Inner DetectorHeat loads in the ATLAS Inner Detector

Inside screen/ Insidecold volume Cyostat upto PP3 Total

Pixel b-layer Modules 2310 2310Pigtails 157 157Cables 126 380 470 976Cooling influx 65 585 650

Pixel barrel/disk Modules 10006 10006Pigtals 980 980Cables 1070 1370 3500 5940Cooling influx 435 3915 4350Total 14649 2250 8470 25369

SCT Modules 8200 8200Hybrids 29500 29500Cables 1200 2200 20300 23700Cooling influx 1000 9000 10000Total 38900 3200 29300 71400

TRT Straws 4160 4160Electronics 42240 42240Cables 5000 5000Total 0 51400 0 51400

Thermal enclosures Heaters 2500 2500Cooling influx 200 1800 2000Total 0 2700 1800 4500

Grand totals 53549 59550 39570 152669

JCOV, 25 OCT 2001 Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

Layout of thermal screens and seals in the Layout of thermal screens and seals in the ATLAS Inner DetectorATLAS Inner Detector

JCOV, 25 OCT 2001 Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

Thermal screen – ANSYS modelThermal screen – ANSYS model Geometry:

Inner radius – 547 mm; outer radius – 555.25 mm Thickness – 8.25 mm Length – 1.6 m Cooling pipe – outer diam. 3.175 mm (56 pipes)

Materials Insulation – conductivity 0.046 W/mK (including radiation damage) Outer and inner surface -aluminium foil with thickness 0.05 and 0.15

mm respectively Cooling pipe – aluminium

Boundary conditions Temperatures: outside 15 °C; inside -7 °C Convection: HTC 5 W/m2K on both surfaces Convection inside the cooling pipe: 1100 W/m2K Temperature gradient along the cooling pipe: 2K (-10 to -8 °C)

JCOV, 25 OCT 2001 Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

Thermal screen – ANSYS resultsThermal screen – ANSYS results

Heat generation:

750 W for 15 °C outside

Would be

865 W for 20 °C outside

JCOV, 25 OCT 2001 Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

Thermal screen – ANSYS resultsThermal screen – ANSYS resultstemperature distributiontemperature distribution

Temperature distribution along the inner surface of the model

Temperature distribution along the outer surface of the model

JCOV, 25 OCT 2001 Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

Thermal screen – ANSYS modelThermal screen – ANSYS modelversion with gas gapversion with gas gap

Figure 7. Temperature distribution in the model with a 4mm insulating gap filled with CO2

Geometry like for previous model with different thickness and insulating material

Two CFRP plates with 4 mm CO2 insulation between them

Heat generation 750 W

(radiation between two surfaces not included into ANSYS model)

JCOV, 25 OCT 2001 Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

Thermal screen – ANSYS model version 2 , Thermal screen – ANSYS model version 2 , temperature distributiontemperature distribution

Figure 8. Temperature distribution in the inner surface of the model insulated with CO2

Figure 9. Temperature distribution on the outer surface of the model insulated with CO2

JCOV, 25 OCT 2001 Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

RAL – prototype of thermal screen, RAL – prototype of thermal screen, general viewgeneral view

JCOV, 25 OCT 2001 Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

RAL – prototype of thermal screen RAL – prototype of thermal screen inner and outer surfacesinner and outer surfaces

Internal surface with cooling pipes External surface with heaters

JCOV, 25 OCT 2001 Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

RAL – prototype of thermal screen RAL – prototype of thermal screen preparation for the testspreparation for the tests

JCOV, 25 OCT 2001 Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

Thermal screen – small prototype for Thermal screen – small prototype for heat transfer measurementsheat transfer measurements

Ext. surface mean temp. ~23 °C

Int. surface mean temp. ~8.7 °C

Conductance between CFRP planes = 0.084 W/K

For whole thermal screen heaters will dissipate 980 W

JCOV, 25 OCT 2001 Thermal screens in ATLAS Inner Detector J.Godlewski EP/ATI

ATLAS Inner Detector Thermal Screen ATLAS Inner Detector Thermal Screen summarysummary

Inner Detector layout is very complicated from the Inner Detector layout is very complicated from the thermal management point of viewthermal management point of view

Many separated volumes with different operating temperatures and environmental gases

Lack of space and material budget force us to use Lack of space and material budget force us to use active thermal screens with very aggressive active thermal screens with very aggressive solutionssolutions

Thin insulation Small diameters of cooling pipes

Biggest worriesBiggest worries All feedthroughs for cables, pipes etc. Purging gas its flow and pressure control Dew point and humidity control