Cavitation

Cavitation


Abstract


Cavitation may be defined, as a hydrodynamic phenomenon resulting in the formation of vapour bubbles or pockets in a liquid when it is subjected to reduced pressure at constant ambient temperatures. In general a liquid is set to cavitate when vapour bubbles are observed to form and grow because of pressure reduction. When the phase transition is a result of pressure change ,by hydrodynamic means a two phase flow composed of liquid and its vapour forms which is called cavitating flow .In all common situation cavitation first appears when the pressure is low enough to unbalance the equilibrium of minute volumes or nuclei of un dissolved gas or free vapour which are trapped on entrained foreign matter or in the containing walls of  a liquid. The result is transit un steady phenomenon characterized by a growth of holes or cavities
From a purely physiochemical point of view, cavitation inception in a flowing liquid may be said to be local boiling at essentially constant temperature. However, cavitation is hydrodynamic while boiling is thermodynamic