Thermal striping; an experimental investigation on mixing of jets; Part III Remaining hydrodynamic results from initial experiments

Tokuhiro, Akira; Kimura, Nobuyuki; not registered

Experiments were performed using the WAJECO facility to investigate the thermohydraulic mixing of multiple jets flowing out of a LMFBR core. Mixing is the root of the thermal striping problem. The multiple jets are typically at different velocities and temperatures and may induce thermal stresses upon components they impinge. In our study we modeled the mixing of three vertical jets, the central at a lower temperature than the two adjacent jets at equal temperatures. The jets are quasi-planar. The parameters were the average exit jet velocities (Uo,av) and the temperature difference between the "cold" and "hot" jets (Thc=Thot-Tcold). Measurements of the liquid velocity, initially using laser Doppler velocimetry (LDV) and later ultrasound Doppler velocimetry (UDV), for both our reference single-jet and the triple-jet configuration, comprised Phase I of the experiments (up to 1994). Two reports (TN9410 96-181 and TN9410 96-296; in Japanese) reported on the hydraulic and heat tra