STUDY OF THE AIR TEMPERATURE STUDY OF THE AIR TEMPERATURE AND VELOCITY AROUND THE ATLAS AND VELOCITY AROUND THE ATLAS

MUON CHAMBERSMUON CHAMBERS

Emma Vigo CastellviST/CV Design

CONTENTS

• Situation of the Problem• Solution methodology (CFD)• Boundary Conditions• The Previous Model• The LMCh5 Model• The Closed Model• Conclusions

Study of the Air Temperature and Velocity Around the ATLAS Muon Chambers Emma Vigo, ST/CV, 15 October 2001

SITUATION OF THE PROBLEM

• Types:– BIS, BIL

– BMS, BML

– BOS, BOL

• Concerned by:–Temperature

–Air velocities

THE ATLAS BARREL MUON CHAMBERS

Study of the Air Temperature and Velocity Around the ATLAS Muon Chambers Emma Vigo, ST/CV, 15 October 2001

CONTENTS

• Situation of the Problem

• Solution methodology (CFD)

Study of the Air Temperature and Velocity Around the ATLAS Muon Chambers Emma Vigo, ST/CV, 15 October 2001

SOLUTION METHODOLOGY (CFD)

CFD (Computational Fluid Dynamic) is a method allowing to simulate on computer a wide range of phenomena linked to fluid mechanic (flow

analysis, thermodynamic, heat transfer...)

• Fluid mechanics equations numerically solved

• Domain splitted into cells

• Flow behaviour spatially uniform

• Physical gradients

Study of the Air Temperature and Velocity Around the ATLAS Muon Chambers Emma Vigo, ST/CV, 15 October 2001

cell+neighbours

discretisation or mesh

THE MESH

100’000 elements

Study of the Air Temperature and Velocity Around the ATLAS Muon Chambers Emma Vigo, ST/CV, 15 October 2001

CONTENTS

• Situation of the Problem

• Solution Methodology (CFD)

• Boundary Conditions

Study of the Air Temperature and Velocity Around the ATLAS Muon Chambers Emma Vigo, ST/CV, 15 October 2001

THE UX15 VENTILATION SYSTEMBOUNDARY CONDITIONS

Study of the Air Temperature and Velocity Around the ATLAS Muon Chambers Emma Vigo, ST/CV, 15 October 2001

BOUNDARY CONDITIONSTHE 2D “SECTION”

Study of the Air Temperature and Velocity Around the ATLAS Muon Chambers Emma Vigo, ST/CV, 15 October 2001

CONTENTS

Study of the Air Temperature and Velocity Around the ATLAS Muon Chambers Emma Vigo, ST/CV, 15 October 2001

• Situation of the Problem• Solution methodology (CFD)• Boundary Conditions

• The Previous Model

Results:• Quite optimistic• Middle axis chambers: most solicitated• Minor influence of the racks

Problems: • MDT’s heat load: 30mmW/channel• Not distributed inlet

THE PREVIOUS MODEL (LMCh3)

Study of the Air Temperature and Velocity Around the ATLAS Muon Chambers Emma Vigo, ST/CV, 15 October 2001

CONTENTS

Study of the Air Temperature and Velocity Around the ATLAS Muon Chambers Emma Vigo, ST/CV, 15 October 2001

• Situation of the Problem• Solution methodology (CFD)• Boundary Conditions• The Previous Model• The LMCh5 Model

NEWSLMCh5 MODEL

• Heat load of the MDTs’ electronics

• Distributed inlet

• Transient calculation

Study of the Air Temperature and Velocity Around the ATLAS Muon Chambers Emma Vigo, ST/CV, 15 October 2001

Ventilation Parameters

Air flow rate (m3/h) 60000

Inlet velocity (m/s) 0.085

Inlet air temperature (C) 17

Flow extracted by theupper unit (%) 78.95

Flow extracted by the unitin the pit (%) 21.05

BOUNDARY CONDITIONSLMCh5 MODEL

Study of the Air Temperature and Velocity Around the ATLAS Muon Chambers Emma Vigo, ST/CV, 15 October 2001

BOUNDARY CONDITIONSLMCh5 MODEL

Thermal Loads

BOS, BOL 21.7 W/m * 33.5 W/m2

BML 21.7 W/m* 29.38 W/m2

BMS 21.7 W/m* 33.16 W/m2

BIS 21.7 W/m* 76.84 W/m2

BIL, BIR 21.7 W/m* 52.1 W/m2

Electronic Racks 20 W/m 3.45 W/m2

RPC: BOL BOS BML BMS

28 W24 W20 W18 W

5 W/m2

Tile BarrelCalorimeter

- 8 W/m2

Barrel Coils -10 W/m -3.98 W/m2

(*) corresponding to 65mW/channel

Study of the Air Temperature and Velocity Around the ATLAS Muon Chambers Emma Vigo, ST/CV, 15 October 2001

Study of the Air Temperature and Velocity Around the ATLAS Muon Chambers Emma Vigo, ST/CV, 15 October 2001

6000sec : TEMPERATURE MAPLMCh5 MODEL

Study of the Air Temperature and Velocity Around the ATLAS Muon Chambers Emma Vigo, ST/CV, 15 October 2001

6000sec : VELOCITY MAPLMCh5 MODEL

CONTENTS

Study of the Air Temperature and Velocity Around the ATLAS Muon Chambers Emma Vigo, ST/CV, 15 October 2001

• Situation of the Problem• Solution methodology (CFD)• Boundary Conditions• The Previous Model• The LMCh5 Model

• The Closed Model

WHAT’S NEXT?

• Gaps between chambers: closed + porosity

• MCh: solids with conduction

• RPC’s non conducting heating surfaces

Study of the Air Temperature and Velocity Around the ATLAS Muon Chambers Emma Vigo, ST/CV, 15 October 2001

Status:- Geometry completely finished- Geometry successfully transferred to StarCD- At present: definition of new boundary conditions

CMCh MODEL

Study of the Air Temperature and Velocity Around the ATLAS Muon Chambers Emma Vigo, ST/CV, 15 October 2001

CONTENTS

• Situation of the Problem• Solution methodology (CFD)• Boundary Conditions• The Previous Model• The LMCh5 Model• The Closed Model• Conclusions

Study of the Air Temperature and Velocity Around the ATLAS Muon Chambers Emma Vigo, ST/CV, 15 October 2001

CONCLUSIONS

• Global understanding of the case study

• Velocity doesn’t reach high values

• Temperature gradients could be over the constraints

• Medium axis chambers: most solicitated

• Closed Muon Chambers (CMCh) study being donebeing done

• Next stepNext step: 3D simplified model

Study of the Air Temperature and Velocity Around the ATLAS Muon Chambers Emma Vigo, ST/CV, 15 October 2001

STUDY OF THE AIR TEMPERATURE STUDY OF THE AIR TEMPERATURE AND VELOCITY AROUND THE ATLAS AND VELOCITY AROUND THE ATLAS

MUON CHAMBERSMUON CHAMBERS

Emma Vigo CastellviST/CV Design

Study of the Air Temperature and Velocity Around the ATLAS Muon Chambers Emma Vigo, ST/CV, 15 October 2001

See also: http://evigocas.home.cern.ch/evigocas/atlas_air_flow.html