Cavitation responds to the sudden formation and explosion of a vapor bubble, generally in hydraulic systems such as pumps, throttle valves, and ship propellers. However, they are also found in nature, such is the case of some shellfish such as the pistol shrimp, when it quickly closes its pincers, it forms a small cavitation bubble at the tip of its pincers. Likewise, in dolphins this effect occurs due to the speed with which they swim and is attenuated by the design of their fins that have nerve endings.
The plants cause cavitation when they release dissolved air due to the drop in pressure produced by the evaporation of the water in the upper part of the conduits through which the water circulates, causing serious damage. In the case of humans, it occurs when forcing a joint. For example, in the knee, the capsule dilates and the drop in synovial fluid pressure releases the air that is dissolved in it, collapsing the fluid.
On the other hand, in the oil industry, in hydrocarbon mixtures, it is generally less aggressive. The dynamics of bubble collapse is retarded and smoothed by the presence of gases and vapors. Some gases help the system not to collapse. In addition, if the fluid has a higher viscosity, the formation of bubbles can be further delayed.
Next, we present the types of cavitation:
- Gaseous cavitation: When the pressure around the bubble reaches saturation pressure, the bubble grows by gas transport through the interface. Or, the bubble grows due to a change in pressure, but without changing its mass. This process is usually slow if there are no appreciable convective effects, consequently, implosion effects are not generated.
- Vaporous cavitation: When the pressure around the bubble reaches the vaporization pressure. Unlike soft drinks, this process is very fast because the bubble grows due to the rapid evaporation of liquid through the interface, giving rise to sudden condensation that can cause a lot of damage.
Imagen por Sintech Precision Products Ltd
In the wastewater treatment plant industry, cavitation is used to break down molecules and bacteria. Cell walls break up contaminants and dissolve minerals from organic matter. In the same way, in the Poultry industry the same principle is applied when it acts as a sanitizer and eliminates the possible microbiological load of the fluid on which it is applied. The microbubbles are achieved thanks to variations in pressure produced mechanically.