Numerical and experimental campaigns for lead solidification modelling and testing

The Computational Fluid-Dynamics (CFD) modelling of Heavy Liquid Metal (HLM) flows in pool configuration is investigated in the framework of the SESAME project. This paper focuses on the coupling between numerical simulations and experimental activity with the objective tom ake CFD a valid tool in supportto the designo f safe and innovative Gen-IV nuclear reactors. The attention is focused on the possible occurrence of lead solidification phenomenon. The aim is to demonstrate that the overall modelling of HLM complex systems can include solidification phenomenology by reproducing small/medium scale experiment, making comparison with experimental results, improving the numerical setting (post-test) and evaluating time scales, limitations and computational costs. A dedicated experimental campaign on the SESAME-Stand facility has been performed by the Research Centre Rez (CVR), relying on the use of CFD support, with the specific objective to build a series of datasets suited also for the CFD modelling validation. The numerical simulations of the SESAME-Stand experimental facility performed in STAR-CCM + are described. The model uses liquid lead as working fluid in the pool and air in the cooling channel. By increasing the mass flow rate in the cooling air channel, the solidification process is initiated and the freezing front propagates in the pool until reaching an internal obstacle. The issues encountered in the pre-test simulations have been fully overcome by means of systematic investigations and all the improvements have been applied in the post-test model. A decisive modelling aspect was the correct implementation of the thermal radiation which plays an important role in the cooling process. The numerical model allowed to reach an increased number of initial steady states and accessible transients, according to the experimental matrix. The comparison with the experimental results shows similar temperature configurations and comparable lead frozen fractions in the steady state cases and good agreement in the fast transient solidification-remelting cases.

@Article{PMM20b,
  author       = {Profir, M. and Moreau, V. and Melichar, T.},
  title        = {Numerical and experimental campaigns for lead solidification modelling and testing},
  journal      = {Nuclear Engineering and Design},
  volume       = {359},
  month        = {april},
  year         = {2020},
  publisher    = {Elsevier},
  keywords     = {CFD, HLM, Pool modelling, Thermal hydraulics, Lead solidification},
  doi          = {10.1016/j.nucengdes.2019.110482},
  url          = {https://publications.crs4.it/pubdocs/2020/PMM20b},
}