Cavitation is a phenomenon that occurs in moving liquids when bubbles form due to the phase change that develops when there is a pressure drop. The subsequent evolution of the bubbles leads them to grow in size and later, when the local pressure increases again, violent collapses occur that can produce shock waves and damage to nearby solid objects. The emergence of cavitation is a problem that affects vessels and centrifugal pumps, where there are moving parts that move the surrounding liquid. Most of the research on cavitation has been done in water for a simple reason: ships move in the ocean and the main application of centrifugal pumps is the transfer of water. However, there are other liquids where this phenomenon is also present. This is the case of the cavitation in ammonia-water mixtures, which occur in the process of extraction of nickel in the mining industry. To investigate cavitation, we solve the Rayleigh-Plesset equation, which allows us to study the evolution of bubbles that form inside a liquid due to changes in pressure. To solve it we need to know the thermodynamic properties and the velocity and pressure fields that corresponds to the substance flow. In particular, it is necessary to know the values of the saturation pressure. With this purpose our working group carried out some experiments. The Rayleigh-Plesset equation is solved by taking the flow and pressure inside a centrifugal pump as pre-existing data and different values of the initial size of the bubbles are considered. This is used to make an estimation of the places where the implosions occur and therefore it is predicted in which sites can occur damages in the impellers of the centrifugal pumps.

Acknowledgment: the authors acnowledge DGAPA-UNAM by support under project PAPIITIN114218 "Vorticidad y ondas (internas y de superficie) en dinamica de fluidos".