6th September 2006 1S. Eicher, M. Battistin

Upgrade Thermal Management Workshop

September 6th 2006Bdg 40

Sara Eicher, Michele Battistin

CFD Calculations for the ATLAS Upgrade

6th September 2006 2S. Eicher, M. Battistin

CFD Projects on the Inner Detectors of Experiments

• CMS Tracker Outer Barrel

• ATLAS Inner Tracker

• ALICE Inner Tracking System

6th September 2006 3S. Eicher, M. Battistin

Moisture Removal in the CMS TOB with Nitrogen

(Nicola Gatti, EDMS 503499)

6th September 2006 4S. Eicher, M. Battistin

Moisture Removal in the CMS TOB with Nitrogen

(Nicola Gatti, EDMS 503499)

The Problem - TOB contains silicon sensors which are very delicate and deteriorate

rapidly with temperatures above -10°C; - CMS must undergo a drying and cooling process before starting to work; - Drying phase serves to avoid condensation of steam and possible ice formation; nitrogen, which has a dew point of -70°C is used;

Objective: To evaluate the effect of number and location of inlet/outlet conditions on the overall drying time

6th September 2006 5S. Eicher, M. Battistin

Moisture Removal in the CMS TOB with Nitrogen

(Nicola Gatti, EDMS 503499)

The CFD Model

Geometry and Mesh

• Transient, 2D Model

• 10 kcells

• Isothermal

• Laminar flow

• Constant molecular properties

• Nitrogen taken as dry air

6th September 2006 6S. Eicher, M. Battistin

Moisture Removal in the CMS TOB with Nitrogen

(Nicola Gatti, EDMS 503499)

Results

6th September 2006 7S. Eicher, M. Battistin

Analysis of the CO2 Circulation in the ATLAS Inner Tracker

(I. Wichrowska-Polok, EDMS 591951)

6th September 2006 8S. Eicher, M. Battistin

Analysis of the CO2 Circulation in the ATLAS Inner Tracker

(I. Wichrowska-Polok, EDMS 591951)

The Problem - TRT operates in a Xe-CO2-O2 mixture at room temperature; - SCT and Pixel operate in a nitrogen environment at -7°C temperature; - The remaining ID volume is flushed with 10m3/h of dry CO2; - Dry CO2 serves to keep relative humidity below 1% and avoid nitrogen

leakages from SCT and Pixel enclosures into the ID volume

Objective: To evaluate the effect of location of inlet conditions on the overall flushing time

To estimate the evolution in time of CO2 concentration in the ID volume

6th September 2006 9S. Eicher, M. Battistin

Analysis of the CO2 Circulation in the ATLAS Inner Tracker

(I. Wichrowska-Polok, EDMS 591951)

The CFD Model• Transient, 3D Model• 1800 kcells• Isothermal•Turbulent k-ε model

6th September 2006 10S. Eicher, M. Battistin

Analysis of the CO2 Circulation in the ATLAS Inner Tracker

(I. Wichrowska-Polok, EDMS 591951)

The CFD Model

6 inlets per half geometry

TRT barrelTRT endcap

SCT endcap SCT barrelPixel

4

12

36

5

3a

TRT barrel

6th September 2006 11S. Eicher, M. Battistin

Analysis of the CO2 Circulation in the ATLAS Inner Tracker

(I. Wichrowska-Polok, EDMS 591951)

Results

6th September 2006 12S. Eicher, M. Battistin

Analysis of the CO2 Circulation in the ATLAS Inner Tracker

(I. Wichrowska-Polok, EDMS 591951)

Results

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100 120

time [min]

CO2

conc

entra

tion

[%]

-40

-35

-30

-25

-20

-15

-10

-5

70 75 80 85 90 95 100

CO2 average concentration [%]

Dew

poi

nt [C

]

6th September 2006 13S. Eicher, M. Battistin

CFD Study of the ALICE Inner Tracking System Thermal Behaviour

(Anna Mueller, EDMS 592558)

TPC

FMD

SSD SDD SPD

FMD

T0

6th September 2006 14S. Eicher, M. Battistin

CFD Study of the ALICE Inner Tracking System Thermal

Behaviour(Anna Mueller, EDMS 592558)

The Problem

- ALICE Inner Tracking System (ITS) is made up of 3 different detectors: SPD, SDD, and SSD;

- ITS sits in a very confined area which also contains the Forward Muon (FMD) and T0 detectors;

- There is heat dissipation from cables and electronics in the ITS area; - Around the ITS will be placed the Time Projection Chamber (TPC) which is very

sensitive to temperature variations;

Objective: To determine a suitable ventilation configuration able to remove the heat generated in the ITS surroundings

6th September 2006 15S. Eicher, M. Battistin

CFD Study of the ALICE Inner Tracking System Thermal

Behaviour(Anna Mueller, EDMS 592558)

The CFD Model

• Steady-state, 3D Model

• 700 kcells

• Mixed convection

• Heat dissipation from

SPD, SDD, SSD cables

and FMD, T0 detectors

• Inlets positioned on C

side

Geometry and Mesh

detail

6th September 2006 16S. Eicher, M. Battistin

CFD Study of the ALICE Inner Tracking System Thermal

Behaviour(Anna Mueller, EDMS 592558)

Results

6th September 2006 17S. Eicher, M. Battistin

• CFD have been applied to study the inner tracker detectors of LHC experiments (CMS, ATLAS, ALICE);

• Main investigations deal with determination of temperature, flow and concentration distributions;

• 2 and 3D models under transient and steady-state conditions were used

Summary

6th September 2006 18S. Eicher, M. Battistin

• Large improvement of CFD in accuracy and performance

• CFD can provide insight into fluid flow and heat transfer problems when no resources are available for experimental techniques and prototypes

Conclusions