Cavities "Pit Number" and micro-jets impingements

Abstract

Cavitation pits and erosion were obtained using the rotating disk device, where a steel disk with cavitation inducers and specimens fixed on it rotates inside a water chamber to provide the cavitating flow. These pits were observed with the aid of a scanning electronic microscopy. Micro-jets resulting from cavity collapse cause damages to solid surfaces. Because they are caused by the micro-jets, these pits are approximate circular. The exponent named pit number was calculated using the pit counting, that is the number of pits by area and by time unit. The influence of flow velocity was also analyzed here, and how greater is the flow velocity, how greater is the pit counting calculated. It was also calculated the distance from the collapsing cavity to the wall, considering a conic micro-jet.