Contributions to the simulation and modeling of turbulence and heat transfer in the nuclear industry by Sofiane BENHAMADOUCHE

Sofiane Benhamadouche will start by an overview showing the wide range of Reynolds and Rayleigh numbers which might encountered in the nuclear industry and thus the need of different approaches to model turbulence. A first part will be dedicated to advanced RANS (Reynolds Averaged Navier Stokes) modeling through second moment closures for both the dynamic and the thermal fields. A second part will focus on the need of high fidelity computations, DNS (Direct Numerical Simulation) and WR-LES (Wall Resolved-Large Eddy simulation), for a better understanding of the flow and to feed coarser models such as RANS with reliable data. Both previous parts assume that the wall is fully resolved and the use of these approaches is still limited for industrial applications. A third part will then exhibit practical applications where the concept of wall-functions is needed; at least two examples will be given; RANS simulation of the upper plenum of a PWR (Pressure Water Reactor) at a Reynolds number of 10⁸ and LES of the flow through a complex mixing grid representative of the ones used in fuel assemblies. The presentation will end by mentioning two current challenges: the prediction of the vortex penetration depth in a dead-leg and natural convection along a vertical heated plate at very high Rayleigh numbers of the order of 10¹⁵.

Speaker : Dr Sofiane BENHAMADOUCHE, EDF-France