Innovative Liquid Metal Fast Reactors are among the most promising concepts for the upcoming Nuclear Gen IV; nevertheless, several challenges still have to be overcome before achieving a sufficiently mature understanding of all the involved phenomena. Concerning Thermal-Hydraulics aspects, the correct estimation of the turbulent heat flux contributions and their impact on the predicted heat transfer is still being investigated. Particularly, this becomes relevant when addressing complex geometries, such as the wire-wrapped rod bundles considered for the reactor core, in which simple assumptions may no more be sufficient for a suitable representation of the actual turbulent quantities’ distributions.
The present paper reports on the results of a LES application to a wire-wrapped single rod channel performed adopting the STAR-CCM+ code. The considered fluid is Lead-Bismuth Eutectic Alloy (LBE), often adopted as the working fluid in several experimental facilities built to support the development of Gen. IV LFRs while the considered Reynolds number is in the range of 8600 and the heated length is 0.1 m. The obtained results provide relevant information to be considered for the development and tuning of RANS turbulence models specialized in addressing operating conditions involving liquid-metals: the distributions of the turbulent heat fluxes (THF) is here particularly taken into account.