Turbulent heat transfer is an extremely complex phenomenon which has challenged turbulence modelers for many decades. A limited number of momentum transfer models and not a single turbulent heat transfer model are available in commercial codes, except for the turbulent Prandtl number concept, which consists in applying the Reynolds analogy between the momentum and the thermal field.
It was found, as expected, that the more sophisticated heat transfer models available in some academic codes were superior to the models available in commercial codes. In addition, in the case of liquid metal heat transfer, the Reynolds analogy leads to significant errors. One of the objectives of the European sponsored project THINS (Thermal-Hydraulics of Innovative Nuclear Systems) is to push forward the implementation and validation of more accurate closures for single phase turbulence heat transfer for innovative reactors.
As partner in the THINS project, CD-adapco has implemented an Algebraic Heat Flux Model (AHFM) in STAR-CCM+. In close cooperation, the Nuclear Research and Consultancy Group (NRG) has carried out validation analyses of this model and provided their feedback to CD-adapco for further improvement.
At present, a wide range of test cases have been performed. These test cases include three different flow regimes, namely natural, mixed and forced convection. A detailed parametric study of model constants was also done and will be presented during this session.