Assessment of advanced RANS models to predict the heat transfer for supercritical fluids in vertical tubes

Abstract

The extreme thermophysical property changes of fluids near the pseudocritical point lead to strong buoyancy and acceleration effects, posing challenges for turbulence modelling. This paper aims to assess the performance and applicability of various turbulence models, with the intention of providing a useful reference for quickly selecting appropriate models and for models’ further improvement. Additional Favre-averaged turbulence models were implemented through user-defined scalars in ANSYS Fluent and compared to published experimental and high-fidelity simulation data. This study found that the tested turbulence models have different sensitivities to molecular Prandtl numbers, buoyancy effects, and flow acceleration. For forced convection, all turbulence models can be applied in the case of the flow acceleration number Kv<1.37×10−8, and the ZXY model has the widest application range. None of the tested turbulence models showed generalizability under mixed convective conditions. The Lien-PSA model qualitatively reproduced the wall temperature trends for all tested cases.