No abstract

The paper presents experimental and theoretical investigation of the out¯ow of liquids from single-outlet vessels incorporating a vertical downcomer. In such vessels the liquid leaving through the outlet of the downcomer is replaced by another¯uid, which enters the vessel± downcomer system through the same opening. Experimental results of the variation of the void fraction and pressure in the vessel with elapsed time are presented. It is shown that the¯ow is generally oscillatory, and the conditions required for the establishment of the fully developed oscillatory¯ow are reported. A theoretical model of the fully developed oscillatory¯ow is developed. The model describes well the frequency of the oscillatory¯ow and the variation of the gas void fraction in the vessel with elapsed time. The model somewhat overpredicts the amplitude of the pressure oscillations. Thermodynamic aspects of this¯ow are also considered.