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Ezure, Toshiki; Ito, Kei; Kimura, Nobuyuki; Onojima, Takamitsu; Kamide, Hideki
Kyabiteshon Ni Kansuru Shimpojiumu (Dai-16-Kai) Koen Rombunshu (USB Flash Drive), 6 Pages, 2012/11
A fundamental water experiment was performed in the cylindrical tank geometry to clarify the influences of fluid viscosity on the vortex cavitation. The fluid temperature was varied from 10 
C to 80 C to control the kinetic viscosity 
of fluid from 1.3
10
to 3.710
m
/s. The occurrences of vortex cavitation were detected by the visualization measurement and image analysis. The experimental results showed that the influence of was obvious under the large conditions, while the influence became smaller according to the decrease of . Then, the normalized circulation, 
was installed as an evaluation parameter based on the Burgers Model. As the results, it was observed that occurrences of vortex cavitation in the present geometry could be marshaled on a map by employing and cavitation factor.
Ito, Kei; Ezure, Toshiki; Ohno, Shuji; Kamide, Hideki
Kyabiteshon Ni Kansuru Shimpojiumu (Dai-16-Kai) Koen Rombunshu (USB Flash Drive), 6 Pages, 2012/11
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.