•Helium flow within a heated mini-channels has been analysed using Helium experiments conducted in KIT.•Numerical simulations have been performed for low Reynolds number (Re=4000-10000) helium flows.•Four turbulence models, RSM, k-ε, k-ω SST and V2F were tested.•RSM and SST models are appropriate numerical tools for the heat transfer analysis of HFTM of the IFMIF-DONES. Helium flow at low pressure (0.3 MPa) is used to cool the specimen capsules and the structure of the neutron irradiated High Flux Test Module (HFTM) of the IFMIF-DONES (International Fusion Materials Irradiation Facility- DEMO Oriented NEutron Source). The flow path includes mini-channels with gap-widths less than 1 mm where a high velocity low Reynolds number helium flow is used as cooling medium. The large span of Reynolds numbers from laminar to fully turbulent is a significant challenge for the simulation of the complete HFTM. Four turbulence models, the Reynolds Stress transport (RSM); the k-ε (KE) model; the k-ω Shear-Stress-Transport (SST) model and the V2F model were tested using experiments conducted in Karlsruhe Institute of Technology (KIT). Numerical simulations have been performed for low Reynolds number (Re = 4000–10000) helium flows in a heated mini-channels. The RSM model provides the best heat transfer prediction for the full range of Reynolds numbers. KE and V2F models are not suitable for the simulation of the transitional flows. The accuracy of the SST model can be increased by variation of the time scale limiter coefficient. RSM and SST turbulence models can be considered as appropriate numerical tools for the heat transfer analysis of HFTM.