Direct and large eddy simulation of turbulent heat transfer at very low Prandtl number: Application to lead–bismuth flows

This paper deals with the issue of modeling convective turbulent heat transfer of a liquid metal with a Prandtl number down to 0.01, which is the order of magnitude of lead–bismuth eutectic in a liquid metal reactor. This work presents a DNS (direct numerical simulation) and a LES (large eddy simulation) of a channel flow at two different Reynolds numbers, and the results are analyzed in the frame of best practice guidelines for RANS (Reynolds averaged Navier–Stokes) computations used in industrial applications. They primarily show that the turbulent Prandtl number concept should be used with care and that even recent proposed correlations may not be sufficient.

► We perform direct and hybrid-large eddy simulations of high Reynolds and low Prandtl turbulent wall-bounded flows with heat transfer.
► We use a state-of-the-art numerical methods with low energy dissipation and low dispersion.
► We use recent multiscalesubgrid scale models.
► Important results concerning the establishment of near wall modeling strategy in RANS are provided.
► The turbulent Prandtl number that is predicted by our simulation is different than that proposed by some correlations of the literature.