Cooling Large HTS Magnet Coils using a Gas Free-convection Cooling Loop Connected to Coolers

27th International Cryogenics Engineering Conference and International Cryogenic Materials Conference 2018

Green, Michael A.^1

Lawrence Berkeley Laboratory, Berkeley

CA

94720, United States^1

关键词: Down time;    Flow circuits;    Free convection cooling;    Gas cooling;    Hot spot;    HTS magnet;    Low temperatures;    Temperature drops;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/502/1/012100/pdf
DOI  :  10.1088/1757-899X/502/1/012100

来源: IOP

【 摘 要 】

The cool-down and liquefaction of helium in free convection cooling loops has been demonstrated in superconducting magnets greater than 2 meters in diameter. At 4.4K, temperature drops between the magnet hot spot and the coolers of less than 0.2 K have been achieved in large coils that are more than 1 meter from the coolers. At temperatures greater than 20 K, larger temperature drops between the magnet and the coolers are permitted. This paper shows that free-convection gas cooling can be viable for both cooling and cooling down large HTS magnets. This paper presents the flow circuit parameters needed to achieve a reasonable cool-down time and a low temperature drop between the magnet and the cooler cold heads with no liquid cryogen in the loop.