First of all cavitation is the formation of bubbles when in a liquid pressure drops below the vapor pressure of that liquid. It can happen in machinaries where velocity head increases thus decereasing the pressure head.
Cavitation has been a problem for various machines including pumps. It can cause problems ranging from erosion of metals to decrease in pumping capacities of pumps.
But this phenomena is now being used by boffins as a boon in military technology. We all know that submarines and naval battleships use torpedoes to destroy enemy vessels. Torpedoes that are generally used are quite low-speed. The incoming torpedoes can be easily detected and taken care of by the ships. Therefore not all of them are able to reach their target successfully. Now a new torpedo has been made which is powered by a jet engine. Yes, jet engine that is operating under water. The nose of the torpedo is designed so that enormous cavitation may take place on it. Since jet engine propells it so fast that the velocity head at the tip of nose becomes great, thus making pressure head very low(below the vapor pressure of sea water). This causes great amounts of air bubbles to produce. These air bubbles completely cover the torpedo and a film of air forms around it. Torpedo is now in effect moving through air not water. Since air is less denser than water, therefore there is very small drag force on torpedo. The jet engine plus cavitation helps the torpedo to acheive great speed and the targeted vessel doesnt stand a chance to escape it.
Torpedoes have never been so stunning.
2007-06-20 23:52:52
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answer #1
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answered by Muhammad Ali 2
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Cavitation Technology
The reality of zero-point energy coherence during cavitation bubble collapse within dielectric fluids permits the development of a variety of novel machinery including heaters, mixers, refining equipment and other process applications. Historically cavitation has been considered a nuisance phenomenon to be strictly avoided due to the rapid destruction of pump impellors and process piping components that can occur. Cavitation phenomena, including the new field of Sonoluminescence, are well known to provide temperatures exceeding 106 Kelvin, easily vaporizing metal underwater, with very little power input required.
The plainly obvious excess energy is effectively drawn from the local energetic vacuum. A variety of cavitation equipment is already commercially available including the Hydrosonic⢠pump which operates with a COP approaching 1.5 providing pumping, heating and mixing of various dielectric process fluids and mixtures in a single piece of equipment. Other manufacturers are also entering the field promising even higher energy yields. Cavitation machines will likely be retrofitted extensively to existing infrastructure and industrial process applications.
Principles of Operation:
Cavitation equipment generally employs a unique perforated drum that spins rapidly within a close fitting housing to create cavitation bubbles within the process fluid such that contact between the collapsing bubbles and the components of the pump is not likely to occur. This is necessary to avoid literally vaporizing the internal surfaces of the machine as ZPE is collected from the energetic vacuum via the Casimir effect.
The resulting pressure within such microscopic bubbles is estimated to exceed 1015 kPa by a wide margin during the final stages of collapse toward the fluid state singularity. This bubble implosion effectively converts the tremendous radiation pressure of the vacuum flux that is bearing down on the bubble wall, into an extremely hot vapor pressure within the shrinking bubble. The turbulent flow of these cavitation bubbles also provides extremely efficient, fine mixing for industrial applications.
Cavitation equipment may also employ ultrasonic excitation, to provide resonant oscillation of the pulsating cavitation bubbles that continually expand and then shrink in an ongoing cycle, cohering energy from the vacuum during each collapse phase and then "re-inflating" in response to the ultrasonic energy input. This process has been labeled Sonoluminescence in recognition of the fact that much of the cohered energy yield appears as pico-frequency light pulses sustained by the ultrasonic input.
Cavitation principles can also be applied to molten or fluid metals with similar results and by utilizing implosive gas mixtures within the working fluid, such as hydroxy gas, which effectively replaces the collapsing action of the cavitation bubbles.
2007-06-21 06:08:01
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answer #2
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answered by ♫ Chloe ♫ 6
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Depends on what kind of cavitation you are referring to. In a pump cavitation is when you lose prime.
2007-06-21 06:04:40
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answer #3
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answered by Anonymous
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