Abstract
In order to make clear the mechanism of the velocity slip in the riser of a natural circulation heavy liquid metal MHD generation loop and to find the conditions for reducing the slip loss, the calculation of model flows and the visual simulation experiment have been performed. The calculation is based on the steady one-dimensional flow of dilute deformable bubbles and liquid two-phase model. The reduction of the bubble size, the increase in the flow velocity of liquid and the oblate deformation of bubbles are effective to reduce the slip loss. It is shown that a mercury loop can be simulated by a water loop in the reduced pressure. Such a visual simulation experimental facility has been constructed and the two-phase flow in the riser has been observed. The flow pattern changes from bubble flow to slug flow in the middle of the riser for city water, but the coalescence of bubbles is prevented effectively by adding a small amount of surface active agent. The direct measurement of the flow field in the riser shows that the cross-sectionally averaged velocity of each phase consists with the calculated one satisfactorily.
