Development of a CFD tool for turbulent natural convection and heat transfer simulations of liquid metals

This dissertation investigates numerical techniques for studying turbulent natural convection and turbulent heat transfer systems involving liquid metals. Specifically, two strategies are explored. The development of stand-alone solvers to account for all the occurring phenomena, and a code coupling strategy, where two or more numerical codes are integrated to exploit the different code peculiarities. In this work, the latter approach is realized by coupling the in-house finite element code FEMuS with the finite volume code OpenFOAM, using the open-source MED library for data exchange. Turbulent natural convection is studied in a Differentially Heated Cavity configuration. An anisotropic four-parameter turbulence model is implemented in the FEMuS code and validated against the DNS benchmark for liquid metal-filled cavities. To extend this analysis, the coupling application is first validated in the laminar natural convection regime and then applied to the turbulent case. The volume data transfer algorithm is used to leverage the more accurate thermal turbulence model of the FEMuS code with the extensively validated dynamic solver of OpenFOAM. Turbulent heat transfer is investigated in a liquid metal heat exchanger configuration. A boundary data transfer algorithm is validated using a Conjugate Heat Transfer problem, where thermal coupling occurs between the fluid and solid domains. This technique is then applied to a finned pipe heat exchanger, with FEMuS simulating the turbulent liquid metal flow and OpenFOAM modeling heat conduction in the solid structure.