Effect of Cavitation And How to Remove in Centrifugal Pump

日期 : Mar 2014 - Mar 2014

This project will examine cavitation, the mechanism that causes it, it’s damaging effect on mechanical components in the marine and automobile industry, cavitation mitigation and the practical applications of cavitation. Cavitation is a phenomenon that occurs when bubbles form in a liquid due to a pressure drop, then violently collapse. This is usually a consequence of fluids moving at high velocity when the local pressure falls below vapor pressure allowing small amounts of liquid to vaporize. When the bubble reenters a region of high pressure, the bubble then collapses violently with enough energy and force to erode metal. Damage from a single bubble collapse is almost immeasurable; it is the constant accumulation of damage over long periods of time that causes significant removal of material, hence “cavitation erosion”. The highly focused jets of liquid from the collapsing bubbles blast away micro-amounts of material which eventually gives the surface a pitted appearance. This is commonly a problem for mechanical components such as hydrofoils, propellers, automobile engines and centrifugal pumps in working environments of in the marine, automotive and industrial applications where liquid velocity is high and pressure head is low. However, cavitation is not totally unavoidable as there are several ways to suppress it; this primarily includes increasing pressure head, lowering the liquid’s temperature, good design practices or all of the above. Nor is cavitation always an undesirable phenomenon. It has practical application in the marine industry as a means of reducing drag, enabling objects and hydrofoils designed to function in supercavitating flows can achieve extremely high speeds. The biomedical industry is investigating its application in the treatment of certain diseases such as cancer. Even some forms of marine life use cavitation to catch their prey.