FAIR MT/Cryogenics, Seong Yeub Shim

Beam-Tube Eddy Loss

S. Y. Shim

FAIR MT/Cryogenics, Seong Yeub Shim

Table of contents

• Motivation

• Computation– Highlight data

• Summary

FAIR MT/Cryogenics, Seong Yeub Shim

Motivation

• Early Studies– Simple analytical approach– 2D analysis – 3D analysis

• Analysis issues– Effect of cooling pipe & ribs– Temperature profile during magnet operation

• Improvements in this study– 2D+3D analysis including cooling pipe and ribs– Extract eddy loss and temperature profile during the cycles up to

62th

– Check design criterion

FAIR MT/Cryogenics, Seong Yeub Shim

Operation condition & Criterion

• Operation scenario

– maximum : 1.9 T

– minimum : 0.253 T

– Ramping rate : 4 T/sec

– High field flat top duration : 0.1 sec

– Low field flat bottom duration : 0.8 sec

• Temperature Criterion given by UHV group

– In order to keep UHV • Highest Temperature < 15 K

• Lowest Temperature < 6 K

t 0.412 sec

FAIR MT/Cryogenics, Seong Yeub Shim

Length of the Chamber : 2976 mm

Wall thickness : 0.3 mm

Aperture : 128 mm 58 mm

Rib thickness : 3 mm

Rib pitch : 20 mm

Cooling tube diameter : 5 mm

Cooling tube thickness : 0.5 mm

Dimension

FAIR MT/Cryogenics, Seong Yeub Shim

• FE model 1. VC with Cooling pipe2. Coils3. Air (Vacuum region)4. Iron5. Far field elements

• Material parameter1. c(T)2. k(T)3. M(H) for iron4. = 5.010-7 m5. r = 1

• Eddy current, its loss and the temperature on Beam-Tube are calculated simultaneously.

FE model

FAIR MT/Cryogenics, Seong Yeub Shim

Magnet operation

FAIR MT/Cryogenics, Seong Yeub Shim

Magnetic flux density during machine operation

FAIR MT/Cryogenics, Seong Yeub Shim

Joule Heat Generation due to eddy current (position 1)

The unit in this result is watt/m3. The average power loss is 3.43 watt/m. The result without cooling pipe shows the loss of 2.37 watt/m.

FAIR MT/Cryogenics, Seong Yeub Shim

Temperature profile with respect to the circumference of the VC

FAIR MT/Cryogenics, Seong Yeub Shim

Temperature curve as a function of cycle (time)

FAIR MT/Cryogenics, Seong Yeub Shim

Joule Heat Generation (position 2)

FAIR MT/Cryogenics, Seong Yeub Shim

Change the cooling pipe position

The cooling pipe is shifted to the side of the Beam-Tube, position 2. As we expected, the loss is increased ~ 22 % compared with original position, position 1.

FAIR MT/Cryogenics, Seong Yeub Shim

Temperature profile

FAIR MT/Cryogenics, Seong Yeub Shim

Criterion

FAIR MT/Cryogenics, Seong Yeub Shim

Temperature profile

FAIR MT/Cryogenics, Seong Yeub Shim

Joule Loss Distribution

FAIR MT/Cryogenics, Seong Yeub Shim

Joule Loss Distribution

FAIR MT/Cryogenics, Seong Yeub Shim

Summery of Eddy Loss

Beam-TubeBeam-Tube

Cooling pipe

Beam-Tube

Cooling pipe

ribs

maximum loss 14.37 watt 24.12 watt 25.95 watt

average loss 7.21 watt 11.52 watt 12.4 watt

72 %60 %

Number of SIS100 dipole : 108 Total loss : 1340 watt

• It is 15 % of total dynamic heat load of the FAIR. • In order to reduce the load, the electrical insulation between the cooling pipe and ribs/Beam-Tube is now considered and tested.