Post on 02-Jan-2016
description
CERN P186Magnet cryogenic system update
Yury IvanyushenkovRAL
December 7, 2004
Liquid nitrogen cooling system: Diagram
Drawn by Peter Titus
Fill line
Cold vent line
Flexible transfer lines available at CERN
Flow in
Flow return
CERN flexible transfer line as a fill line
Transfer line pressure drop vs. Fill time
0
2
4
6
8
10
12
14
16
18
0 5 10 15 20 25
Fill time, min
Pre
ssur
e dr
op, b
ar
Internal pipe only
Return pipe only
Both pipes
Fill volume = 300 l of LN
Geometry:40 m of horizontal flexible transfer linewith 4 bends
Conclusion: this line is OK as a fill line if both pipes are in use
CERN flexible transfer line as a cold vent line
Geometry:40 m of horizontal flexible transfer linewith 4 bends
Note:formula for compressible flow is used
Conclusion: this line can not be used as a cold line at high mass flow rate.
Cold line pressure drop vs. Cold nitrogen gas flow rate
0
10
20
30
40
50
60
0 20 40 60 80 100 120
M ass flow, g/s
Pre
ss
ure
dro
p,
ba
r
Internal pipe only
Return pipe only
Both pipes
Cold vent line diameter calculation
Question: what is the optimal diameter for the cold vent line ?
Pressure drop vs. Transfer line diameter
0
5
10
15
20
25
30
35
40
45
50
0 10 20 30 40 50 60 70 80
Int diameter, mm
Pre
ssu
re d
rop
, b
ar 100 g/s
200 g/s
300 g/s
400 g/s
500 g/s
Geometry:40 m of horizontal flexible transfer linewith 4 bends
Note:formula for compressible flow is used
Line int diameter 70 mm
Pressure drop of 1.34 bar for 500 g/s
Cryogenic system cost estimate (Preliminary and not official !)
Item Supplier Cost Quantity Total cost, k£
Fill transfer line AS Scientific, UK £200 /m 40 8
Vent line AS Scientific £200 /m 40 8
Valves Industry £5000 7 35
Cold box AS Scientific ? £10000 1 10
Additional lines AS Scientific £100 /m 40 4
LN2 Dewar CERN 1 2
Equipment installation
CERN + RAL £200 / day 20 4
Instrumentation Industry + MIT+ CERN + RAL
5
Control system Industry + MIT + CERN + RAL
10
Total: 86
Contingency (30 %) 26
Total + Contingency 112