The use of the cavitation effect in the mitigation of CaC[O.sub.3] deposits/Uporaba kavitacije za preprecevanje nalaganja oblog CaC[O.sub.3]

Hard mineral scale fouling results in significant economic losses both industrially and domestically. Recently attempts have been made to use ultrasound to mitigate scale formation and its removal based on the phenomena of cavitation. Cavitation erosion is the removal of material from a solid surface by pressure shock waves associated with the formation and collapse of bubbles. This paper reviews the literature on cavitation erosion of brittle crystalline materials in an attempt to better understand the relationship between the material properties of CaC[O.sub.3] scale deposits and its potential removal by cavitation. The study finds that from a materials perspective cavitation erosion is intimately associated with both a material's bulk properties and importantly to its microstructure. The situation is further complicated because the macro and micro-properties of CaC[O.sub.3] scale are dependent on many factors relating to its depositional environment. The type of scale formed will affect how it is removed by cavitation. Keywords: cavitation, cavitation erosion, ultrasound, scale, calcium carbonate V preglednem clanku je podan pregled literature o kavitacijski eroziji krhkih kristalinicnih materialov z namenom boljsega razumevanja materialnih lastnosti oblog CaC[O.sub.3] ter moznosti za odstranjevanje teh oblog s kavitacijo. Obloge vodnega kamna CaC[O.sub.3] so velika nadloga, s katero se soocamo v najrazlicnejsih industrijskih procesih. Vplivi vodnega kamna v prenosnikih toplote so dvojni: tanjse obloge vodnega kamna lahko bistveno zmanjsajo ucinkovitost prenosa toplote, ker delujejo kot izolator pa lahko povzrocijo tudi notranje pregrevanje grelnega elementa in posledicno okvaro. Vodni kamen lahko tudi mocno zmanjsa pretok skozi cevi. Vodni kamen se na obmocjih s trdo vodo nabira tako v gospodinjskih aparatih, kot so bojlerji, pralni stroji in solarni kolektorji, kakor tudi v industrijskih napravah, kjer zmanjsujejo zmogljivost in zivljenjsko dobo. Nezelene posledice vkljucujejo tudi povecanje vzdrzevalnih stroskov, pogosto menjavanje opreme in visje stroske za energijo. Stroski za preprecevanje in odstranjevanje vodnega kamna v industrijskem in gospodinjskem okolju niso neznatni. Oblikovanje oblog vodnega kamna in kavitacijski fenomeni, vkljucno z mehanizmi kavitacijske erozije, so v literaturi prikazani. Ob zacetnem pregledu literature se izkaze, da je kavitacijska erozija tesno povezana tako z makroskopskimi lastnostmi kot z mikrostrukturo materiala,