Direct numerical simualtion of turbulence in molten salt coolants

Lately, different attempts are being made in validating turbulent models adapted to molten salt coolants. However, the current experimental data on molten salt flows is not accurate enough to allow us for a detailed validation of turbulence models. For this reason, we have developed a Direct Numerical Simulation tool for internal molten salt flows, which is called pyDNSMS. This tool allows us to perform detailed simulations of turbulent molten salt flows confined by a surface, such as the ones obtained in Molten Salt Reactors. Then, we can adapt lower fidelity RANS and LES turbulence models to the results obtained in the DNS simulations. In this paper, we describe the design and numerical implementation of the pyDNSMS tool. The novel aspect of this tool is that it implements a high-order finite volume scheme based in radial basis expansion functions. This allows us to improve the numerical dissipation introduced in classical second finite volume schemes while maintaining the sparsity in the discretized systems of equations. To test the accuracy of pyDNSMS, an example of the of the tool to a molten eutectic FLiNaK flow in a pipe is presented. The results obtain with pyDNSMS are compared against experimental results and lower fidelity Large Eddy Simulaitons.