Flow measurement and simulation of K-DEMO blanket manifold using PIV method

Manifold design of Korean fusion demonstration reactor (K-DEMO)'s blanket has rectangular flow channels and a narrow flow header to prevent neutron leakage and retain TBR (Tritium Breeding Ratio), which may lead to flow mal-distribution in the manifold. In addition, flow separation may occur in a region where the channel area changes suddenly or the channel is bent at a right angle, also, a secondary flow may occur in a channel having a rectangular cross section. In order to ensure the reliability of the thermo-hydraulic analysis in the manifold, it is important to predict those phenomena accurately. This issue also leads to the problem of proper use of the computational mesh and the selection of the turbulence model in the use of CFD. From this point of view, flow measurement data is necessary for the blanket manifold design. Therefore, in this study, a flow measuring experimental apparatus was fabricated and flow distribution in the manifold was measured using PIV method. For validation of CFD, the flow measuring experiment were carried out. For flow measurement, the PIV method was adopted. In result, the local velocity profile and flow distribution in the manifold were obtained. Thereafter, the CFD analysis of the manifold for the three turbulence models (SKE, RKE and SST) was performed and SST model shows good agreement with experiment data. However, since the K-DEMO blanket uses pressurized water, which has similar condition with PWR, it is necessary to check the effect of the physical property variation in the experiment or analysis condition. It is expected that one can use similarity criterion for fluid between model and prototype.