CFD model of ITER CICC. Part VI: Heat and mass transfer between cable region and central channel

摘要

Dual-channel cable-in-conduit conductors (CICC) are used in the superconducting magnets for the Inter-national Thermonuclear Experimental Reactor (ITER). As the CICC axial/transverse size ratio is typically approx 1000, 1D axial models are customarily used for the CICC, but they require constitutive relations for the transverse fluxes. A novel approach, based on Computational Fluid Dynamics (CFD), was recently pro-posed by these authors to understand the complex transverse thermal-hydraulic processes in an ITER CICC from first principles. Multidimensional (2D, 3D) Reynolds-Averaged Navier-Stokes models imple-mented in the commercial CFD code FLUENT were validated against compact heat exchanger and ITER-relevant experimental data, and applied to compute the friction factor and the heat transfer coeffi-cient in fully turbulent spiral rib-roughened pipes, mimicking the central channel of an ITER CICC. That analysis is extended here to the problem of heat and mass transfer through the perforated spiral separat-ing the central channel from the cable bundle region, by combining the previously developed central channel model with a porous medium model for the cable region. The resulting 2D model is used to ana-lyze several key features of the transport processes occurring between the two regions including the rela-tion between transverse mass transfer and transverse pressure drop, the influence of transverse mass transfer on axial pressure drop, and the heat transfer coefficient between central channel and annular cable bundle region.