This report describes a new method to determine the equivalent heat transfer coefficients in CICC's with parallel cooling channels, i.e. the radial heat transfer coefficient between helium flow in the cable bundle and in the central spiral, and the azimuthal heat transfer coefficient between subcables in the bundle. The method is based on the Fourier analysis of the steady state temperature traces during a heat step experiment after calibration of the thermometers. The equations for the average temperature distributions in the cable are solved analytically and the values of the equivalent transverse heat transfer coefficients are obtained as the best fit of the experimental temperature distributions. We show the results of the method by application to a short length sample experiment in the SULTAN test facility using an ITER-type CICC. The special instrumentation includes thermometers to measure the temperature in the center of the conductor and at 6 locations equally spaced in angle around the periphery of the conductor jacket, at 3 cross sections along the sample length. Heathers of different geometry allows generating a variety of heat slugs.

Pressure drop in the ITER PFCI cable-in-conduit conductor (CICC) has been measured at CRPP using pressurized water at room temperature. The PFCI conductor is a dual channel CICC and the coolant flows in parallel in the central channel and in the annular bundle region. In our experiment the flow in the central channel is blocked and the longitudinal friction factor of the annular bundle region is deduced from measurements of pressure drop and mass flow rate. Two conductor samples are investigated, one with and one without subcable/outer cable wraps. The results show that the wraps have a negligible effect on the friction factor, and that the Katheder correlation overestimates the actual friction factor.

No abstract

Abstract-A fundamental understanding of the quench phenomenon is particularly important in the design and operation of magnets using High Temperature Superconductors because the quench propagation velocity is low due to high specific heat at high temperature. We have performed the simulations of a high-current forced-flow conductor model to assess the key quench parameters, e.g. the temperature increase of the normal zone and its propagation velocity, using the CryoSoft code THEA. The sensitivity of these results on conductor design and operation parameters was assessed with a variational analysis. Results show that the helium flow has a beneficial impact on the longitudinal propagation of the normal zone and the resulting reduction of the peak quench temperature.

Abstract-A new integrated computer code is being developed for the simulations of the overall behavior of the ITER magnet cryo-system. The existing THEA, FLOWER and POWER codes, assembled as modules of a computational environment (SuperMagnet) have been upgraded to perform global simulations of the cooling circuit for the ITER magnet system. The thermal coupling resulting from the generic geometric configurations has been implemented to realize quasi-three-dimensional simulations of the winding pack. In this paper we present details on the model.