Flow visualization of coolant in cable-in-conduit conductor

Flow visualization to observe the flow behavior of a coolant in a cable-in-conduit conductor was performed by nuclear magnetic resonance (NMR) imaging. A dummy conductor in which many vinyl strings were inserted into an acrylic tube was used for visualization. Regions of both high and very low flow velocity, in comparison with the average velocity, existed in a cross section of the conductor. This fact shows that the flow behavior of the coolant in the cable-in-conduit conductor is not homogeneous but heterogeneous. Thus it is not possible to directly apply a numerical code based on homogeneous flow behavior to stability analysis of the cable-in-conduit conductor