[1G08-12] Multiphase Flow

[1G11] Experimental study on the flow regime and breakup of liquid jet discharged from sudden contraction nozzle

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

Keywords:Single-phase jet, Sudden contraction nozzle, Flow regime, Breakup length, Vortex shedding, Hysteresis

When liquid sodium being discharged from the secondary system of SFR, the liquid jet may impinge against the solid surface of other device and generate the splashing droplet, which could make the accident more serious by increasing the contact area between sodium and air. The quality and size of splashing droplet depends on the state of liquid jet at the moment of impingement. In this work, the sudden contraction nozzle was designed to reproduce a real damage hole in an leakage accident and the liquid discharged from these nozzle was observed. According to the experimental visualization of this work and the conclusion of previous work, the vortex generated at the structure of sudden contraction inner the nozzle determines the flow regime of jet and dominates the jet breakup within a certain flow rate region.