Investigation of jet induced by direct contact condensation using PIV

Steam Direct Contact Condensation (DCC) is an effective way to condense steam in a pool of water. This method of condensation is widely employed in the containment of nuclear power plants. One of the limitations of DCC is the generation of non-uniform temperature distribution in the water pool, which can result in slow but steady pressurization of the containment. Due to the non-linearity of the problem the evaluation of the temperature distribution in the pool cannot be established by simple theoretical analyses but computational models are deemed necessary (e.g. Computational Fluid Dynamics (CFD) and Lumped Parameter (LP) codes). Existing models could be validated only qualitatively because the experimental evidence is composed fundamentally of video acquisitions, which does not allow for a correct comparison of the phenomena. In this paper the authors will present PIV results of a small-scale facility during DCC measuring the jet induced by chugging. The authors have found that the water flow induced by the bubble implosion contains several similarities with continuous and synthetic jets (e.g. velocity spreading) following the self-similar properties of the jet theory. The period of the implosion can be quantified with the current methodology to be around 0.025 s and it has been shown to be independent on the water temperature.