Measurement and simulation of manifold flow distributions in nuclear reactor applications

In many nuclear and non-nuclear applications flow is distributed to various parallel flow paths through manifolds or inlet headers. Examples include the primary heat transport inlet headers in a CANDU reactor or the distribution headers in the moderator system flow paths. In this paper, several experimental facilities have been constructed to measure the flow distribution in such complex manifolds and to elucidate the accuracy of CFD tools for these geometries. The flow distribution between the manifold nozzles is measured using a variety of inlet flow conditions (e.g., feeding the manifold from both sides at different flow rates etc.) under well controlled conditions. The manifold flow field is computed using various Reynolds Averaged Navier-Stokes Equations (RANS) based turbulence models and compared to experiment. The realizable k-ε model results were found to satisfactory agree with measured flow distributions.