PhD position in anisothermal turbulent two-phase flows The research on the interaction between a spray and a hot wall is related to several application fields. In the context of the nuclear safety, this interaction is one of the key phenomenon for the cooling of a Pressurized Water Reactor (PWR) core in case of evaporation of the primary coolant due to an accidental pipe break. We consider vapor-droplet flow through a bundle of ballooned fuel rods, their wall being at a relatively high temperature.
The PhD work will be focused on the multi-scale analysis of this flow in view of its numerical simulation. According to the size of the system studied, the use of the RANS (Reynolds Averaged Navier-Stokes) approach to solve the flow is targeted. In this approach, phenomena at the droplet scale are not solved but rather modeled. The main goal will thus be to study their modeling -in the RANS framework- taking special care of their interaction with turbulence and thermal gradients. The PhD student will first rank by importance the different local phenomena: turbulent fluctuations, evaporation, coalescence, break-up, radiative heat transfer, droplet hydrodynamics. The wall-droplet interaction is currently studied by a PhD student in the LEIDC laboratory team at the IRSN. Secondly, the PhD student will improve the averaged models of mass, momentum and heat transfers through the flow. The interaction between turbulence and phase-change should deeply affect these transfers. We expect in particular the currently existing models not to be well suited to predict the turbulent fields “seen” by the droplets in presence of phase change. Finally, the improved models will be assessed using numerical simulations of fuel rod bundle cooling experiments.
Location : LEIDC at the IRSN (Aix en Provence - France)
PROMES, CNRS, UPR 8521 (Perpignan - France)
Advisor : Pr. Françoise Daumas-Bataille (PROMES)
