An evaluation of the inlet flow reduction for a cable-in-conduit conductor in pulsed operation

The cable-in-conduit conductor (CICC) is applied for large devices, such as the fusion magnets, because it has a high mechanical and electrical performance potential. Also, CICC has advantages when applied for pulsed operation coils, such as the fusion mag nets and superconducting magnetic energy storage coils, because of its thermal and hydraulic performance. Superconducting coils made from CICC have a cooling path and the coolant of the supercritical helium circulates through the inside of the CICC. When the coil has heat generation due to the AC losses, the CICC has the advantage of being able to remove heat due to the large wet perimeter. The inlet flow reduction is caused by the heat generation of the conductor. The inlet flow reduction provides a limit to the stable pulsed operation of the coil. The inlet flow reduction is measured and discussed for the CICC in this paper. The design criteria of the inlet flow reduction is introduced for the CICC. The zero flow temperature is defined to achieve this purpose. The initial flow rate can be estimated by this criteria, which is applicable for the forced flow conductor, as well as for CICC. (C) 1998 Elsevier Science Ltd. All rights reserved.