E. Da Riva, S. E. Wojnarska PS Ventilation - Run mode results -

E. Da Riva, S. E. Wojnarska 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 m 3 h -1 at Technical Rooms inlets, 5000 m 3 h -1 at the center of the ring RVS: m 3 h -1 at TR1 and TR2, m 3 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 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 Inlet layouts StandardMagnet-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 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

E. Da Riva, S. E. Wojnarska Galleries flow rates  Nominal flow rates were expected to be: m 3 h -1 at big galleries (g1, g3, g5,g7) m 3 h -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 )

E. Da Riva, S. E. Wojnarska Velocity profile z=2 and z=3 StandardStraight-15 Magnet-15

E. Da Riva, S. E. Wojnarska Velocity profile r12 StandardStraight-15 Magnet-15

E. Da Riva, S. E. Wojnarska Pathlines „Standard” FAVSRVS R12 R4

E. Da Riva, S. E. Wojnarska Pathlines „Straight-15” FAVSRVS R12 R4

E. Da Riva, S. E. Wojnarska Pathlines „Magnet-15” FAVSRVS R12 R4

E. Da Riva, S. E. Wojnarska 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 END