Manifolds optimization and pressure drops in the ATLAS TRT CO 2 cooling system Joël Grognuz.

Manifolds optimization and pressure drops in

the ATLAS TRT CO2 cooling system

JoëlJoël Grognuz Grognuz

30.10.03 Manifolds optimization, Joël Grognuz

Manifold experiment Full scale straight half manifold (2m, Full scale straight half manifold (2m,

40 holes for inlet, 3m, 48 holes for 40 holes for inlet, 3m, 48 holes for outlet) manufactured from aluminum outlet) manufactured from aluminum U profiles with plexiglas glued on U profiles with plexiglas glued on top.top.

For fixed QFor fixed Qin/outin/out, measure , measure ppnozzlenozzle(z), (z), and qand qnozzlenozzle(z)(z)

Water Umanometers

Outlet manifold mock-up

Pump

Wisag flow-meterfor Qout

48 holes underthe rail

ez

Holes forpstatic measurements


Manifold experimentInlet first resultsInlet first results:: Flux variation of 40 %Flux variation of 40 % qqnozzlenozzle measurements are measurements are

good for good for ppnozzlenozzle> 12mbar:> 12mbar:

qqnozzlenozzle(z) may:(z) may: be increasingbe increasing have a local minimumhave a local minimum be decreasingbe decreasing

ini

inozzle Qq

40

1, 47.25 Increasing !

depending on holes sizes, Qdepending on holes sizes, Qinin and friction losses and friction losses..


Model

depends on the geometry of the flow at the nozzle: depends on the geometry of the flow at the nozzle: for inlet manifolds, the resistance increases with the for inlet manifolds, the resistance increases with the flow perpendicular to the nozzle, whereas the flow perpendicular to the nozzle, whereas the opposite happens for outlet manifolds!opposite happens for outlet manifolds!

Inlet manifold

221

2

20

nozzle

nozzle

area qareap

c

Outlet manifold

Nozzle flow resistance coefficient:Nozzle flow resistance coefficient:


Model validation (air) InletInlet (( calibrated from 3.7 mm calibrated from 3.7 mm

diameters, Q_{in}=37.5 mdiameters, Q_{in}=37.5 m33hh-1-1))

Outlet Outlet (( calibrated from 2 mm calibrated from 2 mm diameters, Q_{in}= 25 mdiameters, Q_{in}= 25 m33hh-1-1))

q variation = 11%


Dimensioning of TRT manifolds Characteristics:Characteristics:

qqnozzlenozzle(z) unlike (z) unlike ppnozzlenozzle(z) fairly (z) fairly constant with varying Qconstant with varying Qin/outin/out or or ..

Changes in model for COChanges in model for CO22:: density:density: kinematic viscosity:kinematic viscosity: D’Arcy friction factor (from chart D’Arcy friction factor (from chart

for laminar and turbulent flows):for laminar and turbulent flows): Flow resistance coefficient with Flow resistance coefficient with

zero perpendicular flux:zero perpendicular flux:

Manifold cross-section:Manifold cross-section: 52 x 6.35 or 42 x 7 42 x 7.35 mm52 x 6.35 or 42 x 7 42 x 7.35 mm

2,0,0 COair

2COair

2COair

221

2

2)(Re)(Re

wp

ffCOD

z

frictionCOair

H

Poiseuille flow (laminar)

airCO pp 35.12

special setup to measure special setup to measure 00::


Optimized holes distributions (CO2) Inlet Inlet (q(qnozzlenozzle variation = 12%) variation = 12%) Outlet Outlet (q(qnozzlenozzle variation = 24%) variation = 24%)


Pressure drops in system (best case)Flow

[m3/h]Rack- PPF2 30.0 50 6 5.89E-02PPF2-PPF1 3.5 22 35 1.33E-03 Vin

PPF1- manifold 50 2.6 22 26 9.88E-04 6.20E-0290° elbow 0.1 8 35 DPin"T" junction 0.4 8 -10 1.09E-04 110Manifold IN 2.0 11 18 6.82E-04

TRT 4.0 0.8 5.99E-01A Manif OUT: 42 x

7.353.0 13 50 9.01E-04

"T" junction 0.1 9 42 1.18E-05 Vout90 elbow 0.1 9 -20 8.39E-02

Manifold PPF1 2.6 23 19 1.12E-03 DPoutPPF1-PPF2 3.5 23 26 1.51E-03 120PPF2-Racks 30.0 58 3 8.04E-02

TOTAL 81.9 231 7.45E-01

DP [mbar] Volume [m3]

Group of wheels

Path Length, [m]

DH [mm]


Pressure in system (best case)Pressue for TRT CO_2 cooling BEST CASE

-350

-250

-150

-50

50

150

250

0 20 40 60 80

length [m]

p [m

bar] A

B

C


Pressure drops in system (worst case)

Flow

[m3/h]Rack- PPF2 30.0 50 8 5.89E-02PPF2-PPF1 3.5 22 46 1.33E-03 Vin

PPF1- manifold 50 2.6 22 34 9.88E-04 6.20E-0290° elbow 0.1 8 46 DPin"T" junction 0.4 8 -5 1.09E-04 152.6Manifold IN 2.0 11 25 6.82E-04

TRT 4.0 1.1 5.99E-01A Manif OUT: 42 x

7.353.0 13 65 9.01E-04

"T" junction 0.1 9 55 1.18E-05 Vout90 elbow 0.1 9 -10 8.39E-02

Manifold PPF1 2.6 23 25 1.12E-03 DPoutPPF1-PPF2 3.5 23 34 1.51E-03 172PPF2-Racks 30.0 58 4 8.04E-02

TOTAL 81.9 326 7.45E-01

Volume [m3]Group of wheels

Length, [m]

DH [mm] DP [mbar]

Path


Pressure in system (worst case)Pressue for TRT CO2 cooling WORST CASE

-350

-250

-150

-50

50

150

250

350

0 20 40 60 80

length [m]

p [m

bar] A

B

C


CO2 system simulation resultTRT pressure oscillations increase with valve response-time and flow/pressure: (qualitative results)


TRT wheels passive protection Safety valve:Safety valve:

Valves work for Valves work for p>10mbarp>10mbar

Placing valves upstream Placing valves upstream and downstream is not and downstream is not totally safe!totally safe!

Rupture disc:Rupture disc: Space limitation problemSpace limitation problem Accessibility if need to be Accessibility if need to be

changed!?changed!?

5cm


Further work Resurrect the cooling system simulationResurrect the cooling system simulation Define and order components (C-wheel!?, Define and order components (C-wheel!?,

pipe routes)pipe routes) Passive safety device on wheels!?Passive safety device on wheels!? Find a location to build prototype #2Find a location to build prototype #2 Build it!Build it!

Manifolds optimization and pressure drops in the ATLAS TRT CO 2 cooling system Joël Grognuz.

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Transcript of Manifolds optimization and pressure drops in the ATLAS TRT CO 2 cooling system Joël Grognuz.