Modelling and CFD analysis of the DYNASTY loop facility

In this paper, CFD assessment of the DYNASTY natural circulation loop, adopting a RANS turbulence modeling approach, is performed using the OpenFOAM open source toolbox. The DYNASTY facility is designed to investigate the stability and dynamics of heat-generating fluids, in particular molten salts, in a natural or forced circulation regime and as such, it is one-of-a-kind, large scale facility for studying the natural circulation in presence of distributed heating. In this work, a CFD model of the facility is set up and validated by comparing the model results to experimental data obtained during the initial testing campaign of the facility, with water as working fluid. In particular, the equilibrium state of the system is investigated in terms of the mass flow dynamic behaviour and the temperature difference across the cooler section of the loop. It is shown that the CFD simulations adopting the k-w SST turbulence model best reflect the experimental results. The CFD results are also in agreement with a simplified 1D modeling as well as an analytical solution.