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VI Single-wall Beam Pipe testsVI Single-wall Beam Pipe tests

M.OlceseM.Olcese

J.ThadomeJ.Thadome

(with the help of beam pipe group and Michel (with the help of beam pipe group and Michel Bosteels’ cooling group)Bosteels’ cooling group)

TMB July 18th 2002TMB July 18th 2002

TMB: CERN June 2002 M.Olcese – J.Thadome 2

Double Vs. Single Wall Double Vs. Single Wall DesignDesign

Same Same heaterheater

Same Same outer outer envelopeenvelope

Same Same reflective reflective layer layer (moved (moved outside)outside)

58 mm ID

69.2 mm OD

0.8 mm thick Be tubes

Kapton heater

58 mm ID

0.8 mm thick Be tube Kapton heater

69.2 mm OD

Outer jacket: Aluminized

Kapton

CURRENT DOUBLE-WALL BASELINE PROPOSED SINGLE-WALL DESIGN

4 mm thick passive insulation

Reflective layer: Aluminized

Kapton

TMB: CERN June 2002 M.Olcese – J.Thadome 3

Proposed thermal insulationProposed thermal insulation

Nano-porous Silica Aerogel in flexible quartz Nano-porous Silica Aerogel in flexible quartz fiber carrier fiber carrier

Very low thermal conductivity: 10-12 mW/mK @ Tamb Very low density: 0.09-0.12 g/cm3 Radiation length: 250 cm (worst density) Resistant up to 600 °C Contains: mostly inert materials Si oxides, quartz fibers,

not sensitive to irradiation Two available types from Aspen Aerogels:

White grade (Pyrogel UQS) Black grade (Pyrogel CQS): carbon opacified to minimize

the radiation at high temperature

TMB: CERN June 2002 M.Olcese – J.Thadome 4

Thermal conductivity vs. TThermal conductivity vs. T

The thermal conductivity The thermal conductivity of the Carbon opacified of the Carbon opacified type does not change in type does not change in the temperature range we the temperature range we are interested inare interested in

Carbon opacified type is Carbon opacified type is apparently also more apparently also more stable in terms of aerogel stable in terms of aerogel powder releasepowder release

However it contains small However it contains small quantities of carbon quantities of carbon which in case of failure of which in case of failure of the encapsulation might the encapsulation might have a bad impact on the have a bad impact on the pixel detectorpixel detector 0

10

20

30

40

50

60

37 93 260 427

UQS

CQS

TMB: CERN June 2002 M.Olcese – J.Thadome 5

Local effects and Local effects and beam pipe offsetbeam pipe offset

Conduction and radiation are Conduction and radiation are uniform in uniform in , while the convective , while the convective heat flux varies significantly with heat flux varies significantly with his is due to the non his is due to the non symmetric flow pattern in the gapsymmetric flow pattern in the gap

I have found an article on an I have found an article on an experimental study in equivalent experimental study in equivalent conditions (in terms of conditions (in terms of characteristic dimensionless Ra characteristic dimensionless Ra number). The proposed number). The proposed correlations lead in our case to a correlations lead in our case to a max local heat flux 2.6 timesmax local heat flux 2.6 times higher than the average (on the higher than the average (on the top).top).

Other experimental studies show Other experimental studies show that the influence of the beam pipe that the influence of the beam pipe offset up to 5 mm produce a offset up to 5 mm produce a change of both the average and change of both the average and local heat flux of less than 10%local heat flux of less than 10%

The worst case heat flux, The worst case heat flux, which the top B-layer stave which the top B-layer stave will have to dissipate during will have to dissipate during the bake out is 10 W (9% of the bake out is 10 W (9% of nominal cooling capacity)nominal cooling capacity)

conclusion

TMB: CERN June 2002 M.Olcese – J.Thadome 6

Thermal tests on real scale Thermal tests on real scale mockupmockup

1 m long tube with deposited heater 1 m long tube with deposited heater Two layer of Aerogel UQS (total Aerogel thickness of 5-6 mm) with Two layer of Aerogel UQS (total Aerogel thickness of 5-6 mm) with

aluminized kapton encapsulation (total thickness of insulation aluminized kapton encapsulation (total thickness of insulation package 9 mm)package 9 mm)

External cylindrical heat exchanger to simulate the B-layer structure External cylindrical heat exchanger to simulate the B-layer structure (black internal surface to maximize radiation)(black internal surface to maximize radiation)

Tube cooled and maintained at a uniform temperature

Insulating plugBeam pipe with heater and insulation

Tube was heated up to 250 Tube was heated up to 250 °° C and as function of the outer tube C and as function of the outer tube temperature we measured:temperature we measured:

the required heating power (heat dissipated by the B-layer + losses) The temperature distribution on the outer surface of the insulation

1000 mm

TMB: CERN June 2002 M.Olcese – J.Thadome 7

Experimental setupExperimental setup

Heat exchangerMonophase C6F14

cooling unit

Beam pipe mockup

Detail of aluminized kapton

encapsulation

fridge

readout

TMB: CERN June 2002 M.Olcese – J.Thadome 8

T of external cold tube k=0.020 k=0.035 calculated measured (*) % increase

20 117 130 170 31

13 113 134 180 347 82 109 137 190 390 105 142

(*) include the heat losses through cables and at the two endsextrapolated from measurementsmeasured

Equivalent insulation thickness of 8 mm (aerogel thickness = 6 mm)T of outer surface of insulation Heating power

Test resultsTest results

Equivalent thermal conductivity of insulation package is 75% above Equivalent thermal conductivity of insulation package is 75% above the Aerogel expected value (from vendor data sheet): air gaps, the Aerogel expected value (from vendor data sheet): air gaps, radiation?radiation?

Measured heating power is about 35% more than what was expected Measured heating power is about 35% more than what was expected but this includes the heat losses difficult to estimate correctly but this includes the heat losses difficult to estimate correctly

The heating power increases only by 10 % for a B-layer temperature The heating power increases only by 10 % for a B-layer temperature change of 10 change of 10 °° C C

TMB: CERN June 2002 M.Olcese – J.Thadome 9

Temperature distribution Temperature distribution vs. offsetvs. offset

Positive vertical offset does not show significant Positive vertical offset does not show significant changes in temperature distributionchanges in temperature distribution

In case of negative vertical offset the mid and In case of negative vertical offset the mid and bottom temperatures are lowerbottom temperatures are lower

This is confirmed by the measurements of the This is confirmed by the measurements of the total heating power which in case of negative total heating power which in case of negative vertical offset is about 4% higher and it is also in vertical offset is about 4% higher and it is also in agreement with literatureagreement with literature

0

20

40

60

80

100

120

140

top mid bottom

coaxial

5 mm positivevertical offset

5 mm negativevertical offset

Beam pipe

Temperature sensor

insulation top

mid

bottom

5 mm vertical positive offset

TMB: CERN June 2002 M.Olcese – J.Thadome 10

Extrapolation to proposed Extrapolation to proposed designdesign

Extrapolation from Extrapolation from measurements leads to a max measurements leads to a max power of about 200 W/mpower of about 200 W/m

Worst stave position (top) Worst stave position (top) would require a coolant T of would require a coolant T of – 8 – 8 °° C to keep the whole C to keep the whole module below 0 module below 0 °° C C

B-layer temperature

k=0.035 k=0.02 k=0.035 k=0.02

0 143 112 195 143

T outer surf. insulation PowerExtrapolation for 4 mm insulation thickness

-8 °°C

- 4 °°C

0 °°C

1.5 W/module (top stave)(15% nominal cooling capacity)

Flex hybrid

sensorFE

stave

Cooling tube

TMB: CERN June 2002 M.Olcese – J.Thadome 11

New irradiation studiesNew irradiation studies

A sample of Aerogel UQS has been bent at A sample of Aerogel UQS has been bent at the beam pipe radius and irradiated up to a the beam pipe radius and irradiated up to a dose of 5x10dose of 5x101515 pt/cm pt/cm22

It has a negligible contact activation dose It has a negligible contact activation dose The irradiated area of the sample does not The irradiated area of the sample does not

show any visible mechanical degradation show any visible mechanical degradation (cannot be distinguished from the non (cannot be distinguished from the non irradiated one)irradiated one)

TMB: CERN June 2002 M.Olcese – J.Thadome 12

RemarksRemarks

The installation of the Aerogel around the The installation of the Aerogel around the beam pipe is not easybeam pipe is not easy

The aerogel material is wavy and shows The aerogel material is wavy and shows significant non-uniformitiessignificant non-uniformities

The Aerogel cannot be glued : has to be hold The Aerogel cannot be glued : has to be hold in place by the kapton encapsulationin place by the kapton encapsulation

Need to find a better technical solution and to Need to find a better technical solution and to make more practice make more practice

TMB: CERN June 2002 M.Olcese – J.Thadome 13

Next stepsNext steps

check thermal conductivity of last irradiated sample at higher dose check thermal conductivity of last irradiated sample at higher dose (Sept.)(Sept.)

Make vibration tests on thermal mockup (with a conservative Make vibration tests on thermal mockup (with a conservative spectrum) and repeat the thermal tests to check possible loss of spectrum) and repeat the thermal tests to check possible loss of thermal performances due to aerogel powder migration (Oct.)thermal performances due to aerogel powder migration (Oct.)

Make same vibration tests on the irradiated sample and measure Make same vibration tests on the irradiated sample and measure again the thermal conductivity (Oct.)again the thermal conductivity (Oct.)

Assess installation methods including encapsulation Assess installation methods including encapsulation Study design changes to be incorporated in the current baseline: Study design changes to be incorporated in the current baseline:

redesign the support collars, assess the design impact on the wire redesign the support collars, assess the design impact on the wire supportssupports

Make a full VI section prototype??Make a full VI section prototype??

I can manage

I can help