Numerical prediction of flow and heat transfer in an infinite wire-wrapped fuel assembly

• Assessment of different, linear and non-linear, RANS models is performed for an infinite wire-wrapped fuel assembly. • The obtained results, for both flow field and the thermal fields, are compared with the reference q-DNS data. • The considered non-linear models, RSM-EB and SST k-ω cubic, have shown good agreement. Assessment of different Reynolds Averaged Navier Stokes (RANS) based modelling approaches is performed for an infinite wire-wrapped fuel assembly configuration of a Liquid Metal Fast Reactor (LMFR). The geometric fuel assembly dimensions refer to the present MYRRHA design. In total, four turbulence models are considered, i.e. linear k-ω SST, realizable k-ε, k-ω SST cubic and Elliptic Blending model of the Reynolds Stress Model (RSM-EB). For this configuration, a high fidelity reference is available and is used for numerical comparisons. Following best practice guidelines, a thorough mesh sensitivity, as well as a sensitivity analysis on different turbulence models, are performed. Both qualitative and quantitative analysis are presented in terms of velocity, temperature and turbulent kinetic energy profiles. Of all models tested, RSM-EB, along with k-ω SST cubic, provide best performance, especially for the flow and the thermal fields, consistent with their capability of modelling anisotropic effects in turbulent flows characterised by highly three-dimensional cross flow and complex flow channel structures, such as the one studied in this work.