Turbulent mixed convection in an annular passage with radiation: experimental and numerical investigations

This study is related to mixed convection heat transfer of air flowing through an ascending vertical annular passage with significant radiation heat transfer. This configuration leads to a maximum level of heat transfer impairment similar to the one obtained in pipe flows, furthermore, the onset of buoyancy is only slightly delayed compared to pipe flows. Five turbulence models are compared with the experimental data obtained by the Promethee facility. Both k-omega models (Wilcox and SST) tend to overestimate heat transfer in mixed convection while the standard low-Re k-epsilon underestimates it. The AKN model performs poorly in all cases. Finally, only the v(2)-f model is found in close agreement with experimental data for all convection regimes.