抄録
Fundamental experiments on the mixing of horizontally-injected high-density calcium-chloride (CaCl_2) solution in vertically-upward water flow were performed in order to provide basic data on the mixing of boric acid solution from SLCS in a reactor lower plenum during an ATWS of a BWR. In this study, numerical calculations have been performed mainly to predict the boundaries between complete and incomplete mixing (entrainment) observed in the experiments. In the complete mixing, the injected high-density solution is mixed (entrained) completely into the vertically-upward water flow. On the other hand, in the incomplete mixing, the high-density solution is partly entrained into the vertically-upward water flow and partly falls down even in the upward water flow. A continuity equation and momentum equations for the total fluid, and a mass transfer equation for the solute are solved by the finite difference method, by using the low Reynolds number k-ε turbulent model. The numerical calculations have predicted roughly the boundary water flow rate between complete and incomplete mixing.
