Study on droplet generation at the time of a water jet, the liquid film collision

Oya, Naoki*; Okawa, Tomio*; Ohno, Shuji  ; Aoyagi, Mitsuhiro 

It is important to set the diameter of leakage sodium droplet mechanistically for appropriate numerical evaluations of sodium leak and fire behavior in a sodium-cooled fast reactor plant. We performed a fundamental experiment with water in order to clarify mechanism of droplet generation in this study. Impinging water jet on a flat plate was tested for various cases of jet velocity, nozzle diameter and nozzle height. The impinging behavior was visualized by means of a high-speed video camera. We measured the amount of generated droplet and the maximum droplet diameter. Observed jet flow was categorized into following three modes: drop mode which is droplet state flow, jet mode which is straight flow and lump mode which is partially constricted flow. Both the amount of generated droplet and the maximum droplet diameter increased in the following order: jet, drop and lump modes.