Two-channel analysis of QUELL experimental results

We have improved the model presently used in the thermo-hydraulic code Gand alf, adapting it to cable-in-conduit conductors with central cooling channe l such as those developed for the model coils of ITER, In particular the he lium flow in an arbitrary number of parallel channels have now independent velocity and thermodynamic state (pressure and temperature). We demonstrate the capability of the new model by means of comparison to measurements tak en during the QUELL experiment in SULTAN. We compare in particular data on heat slug at zero current and field in a broad range of energy inputs, as w ell as data on quench propagation, to simulation results obtained with the single channel approximation and the newly implemented two-channel model. T he latter achieves significantly better agreement with experimental data, i n particular in the case of slow heating transients such as in heat slug pr opagation tests.