Multiphase Investigation of Water Hammer Phenomenon Using the Full Cavitation Model

The aim of this work is to clarify some issues raised recently on the characterization of the water hammer, by presenting a numerical analysis on the multiphysics taking place. For this purpose, the commercial code CFD-ACE+ is used with the so-called full cavitation model, which takes into account the effect of absorption and desorption of a noncondensable gas. A comparison between two different compressibility models is conducted, making use of an inverse engineering technique, which allows the tracking of the medium speed of sound. Finally, a numerical reproduction of a valve opening is proposed, leading to a sudden acceleration of the fluid and consequent vaporization of the liquid. The numerical results confirm high sensitivity of the water hammer prediction regarding the amount of noncondensable gas present in the liquid.