Proposal of a turbulent Prandtl number model for Reynolds-averaged Navier–Stokes approach on the modeling of turbulent heat transfer of low-Prandtl number liquid metal

Because of their high molecular heat conductivity, low-Prandtl number liquid metal is a promising candidate coolant for various designs advanced nuclear systems such as metal–cooled fast reactors and accelerator-driven sub-critical system (ADS). With the fast-growing computational capacity, more attention has been paid to applying fluid dynamics (CFD) methods in thermal design safety assessment detailed analysis three-dimensional thermal–hydraulic behaviors. However, numerical modeling turbulent transfer remains challenging task. Numerical approaches wall-resolved large eddy simulation (LES) or direct (DNS), which can provide insight into physics flow associated transfer, were widely applied investigate phenomenon. these suffer from enormous consumption are hence limited only simple geometrical configurations with low moderate Reynolds numbers. The Reynolds-averaged Navier–Stokes (RANS) approach Prandtl Prt accounting flux based on analogy still, at least current state most circumstances, feasible practical engineering applications. conventional choice id="m2">Prt order 0.9∼unity many commercial codes not valid metal. In this study, LES/DNS results forced channel up friction id="m3">Reτ 2000 id="m4">Pr 0.01 0.025 used references, varying id="m5">Prt was compared. It found that appropriate id="m6">Prt RANS decreases bulk Peclet id="m7">Peb constant value 1.5 when id="m8">Peb becomes larger than 2000. Based calibrated relation id="m9">Peb , new model id="m10">Prt proposed. Validation proposed carried out available local temperature profile concentric annulus bare rod bundle, well experimental correlations Nusselt circular tube bundle.