E. Da Riva, S. E. Wojnarska 12013-01-16

PS Ventilation- Run mode results -

E. Da Riva, S. E. Wojnarska 22013-01-16

Boundary conditions / assumptions:

Air recirculation system (RVS) and fresh air system (FAVS) are working. The inlet and outlet surfaces for the RVS will be set at two couples of 0.1 m wide continuous rings

placed on the floor (at the sides of the magnet) and at the ceiling Air flow rates:

FAVS: 4000 m3 h-1 at Technical Rooms inlets, 5000 m3 h-1 at the center of the ringRVS: 40000 m3 h-1 at TR1 and TR2, 30000 m3 h-1 other TRs.

Same pressure at all the air outlets. Tunnels leaks not taken into account. Buoyancy and heat transfer neglected.

E. Da Riva, S. E. Wojnarska 32013-01-16

Conventions

“r45” means flow rate in the tunnel between the technical room 4 and 5. Flow rate in tunnels (r12, r23, etc.) is positive when counter-clockwise. Flow rate in galleries is positive when moving radially from the ring center to the outside.

Nominal flow rates

+

+

+

+

E. Da Riva, S. E. Wojnarska 42013-01-16

Inlet layoutsStandard Magnet-15Straight-15

Flow perpendicular to the inlet. Perpendicular flow in the left-half of the inlet.

Flow oriented 15° to the right in the right-half.

Flow oriented 15° to the left in the left-half.

Flow oriented 15° to the right in the right-half.

Flow directed downwards in order to impinge the bottom of the magnet.

E. Da Riva, S. E. Wojnarska 52013-01-16

Tunnels flow rates

Nominal case: ideally, the air at inlets is expected to evenly split 50% right and 50% left. With the “Standard” inflow layout, air impinges the wall in front of the inlet, and a swirling counter-current flow occurs. With the „Straight – 15” the flow is split but still more is going to counter-clock direction. Only with the “Magnet-15” layout, the air coming from the technical rooms splits to the left and the right. Volume average velocity Magnitude: Standart – 0,1184 m/s, Straight-15 – 0,1115 m/s, Magnet-15 – 0,1066 m/s

r12 r23 r34 r45 r56 r67 r78 r81

-6000

-4000

-2000

0

2000

4000

6000

8000

10000Nominal caseMagnet-15Straight-15Standard

Air

Flow

Rat

e [m

3/h]

E. Da Riva, S. E. Wojnarska 62013-01-16

Galleries flow rates

Nominal flow rates were expected to be:

+2750 m3h-1 at big galleries (g1, g3, g5,g7)

- 1500 m3h-1 at small galleries (g2, g4, g6,g8) CFD results are very different from nominal case and seem to be very sensitive on the inlet layout. Important to keep an high average velocity in all the galleries in order to extract the activated air. Globally, the “magnet-15” layout displays the highest average velocity in the galleries (~0.09 m s-1 vs ~0.05 m s-1 )

galle

ry1

galle

ry2

galle

ry3

galle

ry4

galle

ry5

galle

ry6

galle

ry7

galle

ry80.0000

0.0500

0.1000

0.1500

0.2000

0.2500

Air

Vel

ocity

[m/s

]

galle

ry1

galle

ry2

galle

ry3

galle

ry4

galle

ry5

galle

ry6

galle

ry7

galle

ry8

-400

-200

0

200

400

600

800

1000

1200

1400

1600Magnet-15Straight-15Standard

Air

Flo

w R

ate

[m3/

h]

E. Da Riva, S. E. Wojnarska 72013-01-16

Velocity profile z=2 and z=3Standard Straight-15

Magnet-15

E. Da Riva, S. E. Wojnarska 82013-01-16

Velocity profile r12Standard Straight-15

Magnet-15

E. Da Riva, S. E. Wojnarska 92013-01-16

Pathlines „Standard”FAVS RVS

R12

R4

E. Da Riva, S. E. Wojnarska 102013-01-16

Pathlines „Straight-15”FAVS RVS

R12

R4

E. Da Riva, S. E. Wojnarska 112013-01-16

Pathlines „Magnet-15”FAVS RVS

R12

R4

E. Da Riva, S. E. Wojnarska 122013-01-16

Conclusions

„Standard” model is still counter clock wise The closest to the nominal one is the „Magnet – 15” model Low velocities in the galleries (the best with Magnet – 15)

E. Da Riva, S. E. Wojnarska 132013-01-16

END