Study on Behavior of Vortex Cavitation around Suction Pipes in Sodium-Cooled Fast Reactor Geometry

抄録

Cavitation is a key engineering issue in various turbo-machinery applications. Also in an advanced loop-type sodium-cooled fast reactor (advanced SFR), vortex type cavitation has become an important issue to be cared from the viewpoint of the integrity of structural materials of the reactor. Therefore, a method to evaluate this type of cavitation needs to be established. In this paper, vortex cavitation behavior is studied using a 1/22-scale upper plenum water model of the advanced SFR. Vortex cavitation occurrences are quantitatively grasped through visualization measurements, including the transient behavior under various conditions of inlet velocity at the suction pipe, water temperature, and system pressure. In addition, the relationships between the local velocity around a vortex and vortex cavitation occurrences are investigated based on the results from the visualization and Particle Image Velocimetry measurements. The experimental results show the difficulty of evaluating vortex cavitation occurrences based on a macroscopic parameter, i.e. cavitation factor. In contrast, the results of vortex evaluation with local circulation give a good agreement with the vortex cavitation occurrence data. Therefore, the local circulation is considered as the most important evaluation parameter.