Cavitation Forms

The phenomenon of the cavitation occurs by an abrupt fall of the pressure of a fluid below the vapour pressure, this must to abrupt changes in the speed of the flow or by an effect of it drained partisan given generally by great columns of fluid as it is the case of the pumps. In practical terms this fall of pressure, brings about the formation of steam bubbles, which travel by the fluid until in another place, the pressure is restituted bringing about an abrupt condensation of gases, generating an implosion, this determined fort impact, in the contiguous surfaces since the denominated effect of the shaped charge is generated or Monroe, in which they themselves converge all the waves to a same place confining itself, this generates punctures very important that they end up destroying the metal. It is also known that these gas bubbles sometimes are not such, as all we know the fluids are non-compressible, but due to special conditions of speed variation, the fluid withdraws momentarily, being created a hole, that does not have gas it has or it in very little measurement, immediately later when the speed is regularized, the molecules of the fluid hurry abruptly towards the orifico which I am generated, causing a fort hits in the convergence point, the same that goes, towards the place where there were no molecules hurrying, that are the wall of the next surface. As it is known the elements, that undergo the greater deterioration by this type of phenomenon are the helices, the pumps, fuel pipes, turbines of hydroelectric generation, rudders of boats, etc. Although the cavitation is a phenomenon normally identified like negative and necessary to avoid, by his effects it has two useful applications essentially, the cleaning, by means of cavitation and ultrasound and the denominated supercavitation, which allows the movement of a body submerged in a fluid, at speeds the 500 superiors to Km/h even near the sonic speed, at the moment is investigated widely with military objectives. It is not very easy to avoid the cavitation, since the liquid means cannot be controlled in many case, for these case which becomes is to modify geometries of the elements and/or to realise a careful sizing of the involved equipment. When the fluid can be controlled, as it is the case of fuel pipes or lines of water cooling, can be made use to some alternatives, like slow down of flow, maintaining cleanest the fluid possible, to diminish the temperature of the same, or to place dampers that the fluctuations of speed absorb The cavitation usually is detected by the noise that causes which is similar pebble snore even moving this also generates vibration that is easily detectable especially because they are possible to be appreciated in graphic the denominated humps of camel, unequivocal sign of the phenomenon cavitatorio. The cavitation although is light, brings about clean wearing down since the surface of the metal, of the oxide, which is a layer, protector leaving to shortage the metal, at that moment is created a galvanic battery, that increases the erosion of the surface, since the metal this subject to the action of the cavitation and the one of the corrosion destroying itself very quickly Original author and source of the article.