CAVITATION EROSION OF COPPER AND ALUMINUM IN WATER AT ELEVATED-TEMPERATURE

Cavitation erosion tests were carried out in tap water on aluminium an d copper samples in a rotating disk cavitation test apparatus, to stud y the effect of water temperature on cavitation dynamics and cavitatio n erosion. A shift in the position of the erosion zone with changing t emperature was observed. This was explained in terms of the effect of temperature on the pressure gradient giving rise to cavitation. As had been found for vibratory cavitation, the erosion rate in this case (f low cavitation) increased with increasing water temperature and reache d a maximum at approximately 65-degrees-C. However, in contrast to cop per, which exhibited the usual behaviour, the erosion rate of aluminiu m did not decrease with further temperature increase. This apparent an omaly was investigated by employing specially developed cells for corr osion rate and temperature measurements on a cavitating aluminium samp le. It was found that an increase in corrosion rate was mainly respons ible for the high cavitation erosion rate at temperatures above 50-deg rees-C.