Development of vortex cavitation model for numerical simulation

Ito, Kei; Ezure, Toshiki ; Ohno, Shuji  ; Kamide, Hideki 

The prevention of vortex cavitation is one of key factors in the safety design criteria for sodium-cooled fast reactors. The authors are developing high-precision numerical simulation algorithms for submerged vortical flows to investigate the onset condition of the vortex cavitation. In this paper, an unsteady vortex cavitation model is presented, which is derived from the axisymmetric unsteady Navier-Stokes (N-S) equation. This model employs an approximate solution of the N-S equation to calculate the velocity and pressure distributions, and the cavitating radius is determined on the basis of the mechanical boundary condition on a gas-liquid interface. As a basic test, circumferential velocity distributions are compared between the cases with and without the cavitation model. The result shows that the peak velocity becomes lower by the occurrence of the cavitation. In addition, the effect of the surface tension is also examined in this paper.