The goal is to model the radial transfer terms for 3D flows within fuel bundles of PWR cores. The industrial context consists in the thermal-hydraulics safety code CATHARE 3 that has to reproduce 3D effects when strong assymmetries occur in specific accidental configurations while computing the whole core geometry. The main term to be modeled is the rods drag, that depends on the flow regime and its incidence angle. We will first consider only single-phase situations.
The modelling work will rely upon both the experimental data from the METERO-V rig and LES computations obtained with the TrioCFD code.
Advection momentum radial transfers will have to be properly identified to not be confused with diffusion phenomena and to allow for proper modelling. Finally this work will be extended to a 2-fluid configuration (either dispersed bubbles or droplets, to be defined). This will shift the focus onto modelling the 3D interfacial friction, two-phase friction multplier and void dispersion terms. At this point the goal will be to extend further the CATHARE 3 prediction capabilities for 3D flows in fuel bundles, for use in specific two-fluid conditions.