Numerical study on influence of Ohnesorge number and Reynolds number on the jet breakup behavior using the lattice Boltzmann method

Iwasawa, Yuzuru*; Abe, Yutaka*; Kaneko, Akiko*; Kanagawa, Tetsuya*; Saito, Shimpei*; Matsuo, Eiji*; Ebihara, Kenichi   ; Sakaba, Hiroshi*; Koyama, Kazuya*; Nariai, Hideki*

For the safety design in which heat is properly removed from the molten fuel after the core disruptive accident in a sodium-cooled fast reactor, the estimation of the breakup behavior of molten fuel discharged into the coolant like a jet is desired. In order to investigate the influence of viscocity on the jet behavior, we simulated a jet discharged into a coolant using the three-dimensional lattice Boltzmann model for two-phase fluid, and examined the influence of Ohnesorge number and Reynolds number on the jet behavior. As a result, we made clear that it is necessary to consider viscosity of the coolant as well as that of the jet for the estimation of jet behavior.