抄録
The prevention of vortex cavitation is one of key issues in the design studies on various fluid machineries. For example, in a large-scale sodium-cooled fast reactor in Japan (JSFR), the vortex cavitaion has to be prevented because the vortex cavitation can damage structural surfaces in the pipe. Therefore, the authors are developing a CFD code which can evaluate the vortex cavitation accurately. In this paper, the theoretical modeling of an unsteady vortex cavitation is proposed. In this model, the cavitation behavior in a strong sub-surface vortex is calculated based on the axisymmetric unsteady Navier-Stokes (N-S) equation. Then, the cavitating radius is determined by comparison of the calculated pressure with vapor pressure. As a basic test of this model, vortex development and resulting cavitation are calculated. The results show that the growth of the cavitating region with the development of circumferential can be calculated. In addition, the effect of the surface tension is given in an appropriate physical manner, and the fluctuation in the pressure at infinity leads to the fluctuation in the cavitating radius. The effect of gas rotation on cavitation behavior is also investigated.
