Anti project. F. Raffaelli. INFN CERN, April 05 th, Thermal Analysis of the Anti transportation. -Calculation of the manhole loads due to the valve and vacuum pump. -Conclusions

2 F. Raffaelli - 14/07/2010 Thermal Analysis of the Anti transportation. -Steady case. -Evaluation of the optimal thickness of the insulation. -Simulation of the power applied to maintain the anti at the room temperature. -Transient analysis

3 F. Raffaelli - 14/07/2010 -Steady case.. -Thermal model. -The geometry considered is referring to the anti 1-5 with the steel covers. -In the bottom of the anti there is a cushion of Sylomer R (190mm). -All the lateral surface and the top are surrounded by 100mm of wool glass Total steel cylinder height1550mm Steel thickness ends covers40mm Average steel cylinder thickness27mm Outer cylinder diameter2116mm Flange thickness62mm Inner flange diameter1920mm Sylomer lower cushion thickness190mm Glass wool thickness100mm Geometry data

4 F. Raffaelli - 14/07/2010 -Steady case.. -Material thermal data Material Thermal conductivity (watt/m 0 C) Specific heat (Joule/kg) Density Kg/m 3 steel Glass wool Sylomer R *220 The sylomer R has a low thermal conductivity providing a good insulation. The thermal analysis require the evaluation of the average film coefficient for a case of free convection. This can be calculate using numerical correlation that depends of the difference between the insulation wall and the external temperature. For this reason an iterative calculation is required. We consider the case of external and the steel temperature respectively 0 o C and 20 o C

5 F. Raffaelli - 14/07/2010 -Steady case.. -Film coefficient evaluation We start using a trial difference of temperature using the bellow correlation we calculate the Nuselt number and after the film coefficient. Where: g is the gravity acceleration;  ap is the air coefficient of thermal expansion;  t is the temperature difference between the air and the surface; Dc 3 is a geometrical parameter depending of the geometry considered; a 2 is kinematic viscosity. All the air parameters expect  ap are calculated respect the average temperature between the reference air and the wall temperature. We perform the calculation and we verify that the assumption are satifyed, otherwise we recalculate the film coefficient using a different difference of temperature. Using external temperature of 0 o C and internal temperature of 20 o C we evaluate a film coefficient of 3 watt/m 2 o C.

6 F. Raffaelli - 14/07/2010 Based on heat transfer on Cylindrical geometry we come out with the analytical formulas where x is the insulation thickness. Where: Ti internal temperature Te external temperature Hc cylinder height Rec external steel cylinder radius Ri internal steel cylinder radius Stb top surface Kinst thermal conductivity of the insulation Kst thermal conductivity of steel

7 F. Raffaelli - 14/07/2010 FEM analysis axial symmetric model The total thermal input calculated with FEM is watt. The analytical model gives 145 Watt.

8 F. Raffaelli - 14/07/2010 FEM analysis axial symmetric model Applying on the cylinder external surface an uniform power for a total of 140 w. The max temperature reached is 21 o C with the external temperature is maintained to 0 o C

9 F. Raffaelli - 14/07/2010 Transient FEM analysis Initial conditions: All material is set to 20 o C a stepped temperature of 0 o C is applied outside. The total time of transient is three days ( seconds) We show some graphs referring to 12 hour and three days. The graph shows the temperature of nodes at the half way of the height of the cylinder. The top curve is on internal surface of the cylinder the lower the external surface We can see that the steel is still warm. The fact that the temperate of insulation drop so quickly respected to the steel is related to the different thermal diffusivity of the two material (15 times smaller)

10 F. Raffaelli - 14/07/2010 Transient FEM analysis 12 hours and 36 hours 100 mm of insulation temperature distribution. In the case of 50mm the final temperature reaches 6.4 degree after 36 hours.

11 F. Raffaelli - 14/07/2010 Transient FEM analysis Three days 100 mm of thermal insulation

12 F. Raffaelli - 14/07/2010 Man hole valve and vacuum pump Configuration of the valve and vacuum pump on a man hole ISO K 630 We evaluate the moment and shear acting on the anti cylinder

13 F. Raffaelli - 14/07/2010 Man hole valve and vacuum pump Schematic calculation according PED standard EN 13445

14 F. Raffaelli - 14/07/2010 Man hole valve and vacuum pump Actual welding situation: internal there is a sealing weld, external there are 21 weld of 50mm length section 4mm.

15 F. Raffaelli - 14/07/2010 Man hole valve and vacuum pump Fea model with six clamp show that it is critical the attachment of the valve to guarantee the tightness. A good adapter must be made between the ISO K the valve to load uniformly the flange. The flange has 12 clamp with screw M12 that are sufficient to take all loads.

16 F. Raffaelli - 14/07/2010 Conclusions -From the model we can conclude that results are in agreement with real transportation considering the 50mm insulation and three days. If fact the heat flow estimated, it is considering a perfect cylinder insulated, should allow maintaining the steel cylinder at reasonable temperature in 12 hours with no heating system. In the first phase of the cooling the external insulation temperature goes down relatively fast respect the steel. This is explained considering the different thermal diffusivity of the insulation respect the steel. The thermal diffusivity of the insulation is fourteen times smaller than the steel so causes the delay on the cooling down of the steel cylinder. If the transportation time is as long as three day the actual envisaged insulation will not prevent the cool down of the steel. -The actual man hole cannot support the valve and the pump itself. We need additional supports. We can make the next one such to support the valve and the pump directly. It is important to make a good adapter to load uniformly the flange of the man hole