Text: CAVITATION AS A POWER SOURCE - What Others Say "The collapse of the smaller vapor filled cavities [during cavitation] causes many extreme results as the intensity of the resulting shock wave may be considerably greater than the originating action." (1) "Cavitation is mainly known for its harmful effects, namely, loss of performance, erosion, and noise.(2) However, attempts to induce and harness cavitation for useful purposes have been increasingly successful. [For instance] In high-pressure jets, cavitation has for some time now been purposely induced in order to increase their drilling, cutting, and cleaning capabilities."(3) "... pressure of thousands of atmospheres may be developed at the moment when the cavity collapses to a small fraction of the original diameter. Such collapses are, therefore, bound to cause enormous effects, as high kinetic energies are being concentrated at very small spots."(4) "To give an idea of the amazing effects of cavitation, it may be pointed out that after a destroyer had rushed for several hours at maximum speed, the armor plates above the propeller were pierced by a hole of the dimension of about one square foot."(5) "If the cavities are larger than about --- in diameter the pressure at the solid [boundary] is about 1000 atmospheres (14,000 psi)."(6) "While denucleated liquids may have a number of practical applications such as their use for a transmission medium in high intensity ultrasonic equipment, the use of enhanced nucleation in liquids could have far reaching possibilities. If it were possible materially to reduce the power necessary for active cavitation many of the actions utilizing the phenomenon of cavitation would become more economic and practical from the point of view of commercial exploitation."(6) (1) Crawford, Alan E.,Ultrasonic Engineering with particular reference to high power applications; Butterworths Scientific Publications, 1955, London. page 26. (2) Hammitt, F. G., "Cavitation and Multipahse Flow Phenomena", McGraw-Hill International Company, 1980. (3) Johnson, V. E., Jr., Chahine, G. L., Lindemuth, W. T., Conn, A. F., Frederick, G. S., and Giacchino, G. J. Jr., "Cavitating and Structured Jets for Mechanical Bits to Increase Drilling Rates." ASME Journal of Energy Resources Technology, Vol. 106, 1984, pp. 282-294. (4) Prakash, Satya, and Ghosh, Ashim K., "Ultrasonics and Colloids", Scientific Research Committee, Allahabad, India, 1961. (5) Prakash, Satya, and Ghosh, Ashim K., "Ultrasonics and Colloids", Scientific Research Committee, Allahabad, India, 1961. (6) Crawford, Alan E.,Ultrasonic Engineering with particular reference to high power applications; Butterworths Scientific Publications, 1955, London.

See Also: WATER HAMMER AS POWER SOURCE; SCHAEFFER STEAM MACHINE; SUPERCAVITATION

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