Scaling Analysis of Mixing and Thermal Stratification in Passive Containment

The passive containment cooling system (PCCS) is one of typical passive systems of AP1000, which is a passive condenser system, designed to remove energy from the containment for long term cooling period after a postulated reactor accident, like LOCA or MSLB. One of the key phenomena of PCCS is mixing and thermal stratification inside the containment. In order to establish empirical correlations and develop model of this phenomenon, the experimental study is essential. Because it is difficult to use prototype system for research, so a scaling analysis is needed to design an experimental facility with smaller scale and accelerated time to simulate the prototype system. In this paper, a scaling method for mixing and thermal stratification is given and gets the governing equations and scaling criterions. In final, a group of primary parameters of the experiment, such as mixing time and volume rate of flow, is given in the form of geometric scaling ratio which is chosen by the designer.