[1K08-12] Multiphase Flow

[1K11] Experimental study on the flow characteristics of liquid jet discharged from sudden contraction nozzle

*Guofu Sun¹, Tomio Okawa¹, Mitsuhiro Aoyagi², Akihiro Uchibori², Yasushi Okano² (1. UEC, 2. JAEA)

Keywords:Sudden contraction nozzle, Liquid jet, Flow pattern, Vortex

When liquid sodium leaks from the secondary system of SFR, it might impact device surfaces, generating splashing droplets, posing a risk due to a rapid increase in liquid sodium's specific surface area. Splashing characteristics hinge upon jet states. Utilizing sudden contraction nozzles simulating real leakage hole, flow characteristics of the liquid jet was observed from high-speed camera. Hysteresis of flow pattern transition was noted. The growth, shedding, and collapse of the vortex generated inside the nozzle likely caused the flow pattern transition, and subsequent observations supported this hypothesis. Based on these, a flow pattern map was proposed.