ACOUSTIC-EMISSION IN MONITORING SLIDING CONTACT-BEHAVIOR

This paper describes the usage of acoustic emission (AE) measurement i n monitoring sliding contact behaviour in mechanical face seals. The m echanical face seal works normally in boundary lubrication region, If the leakage rate of the seal rises, hydrodynamic lubrication takes a p art in the sliding contact. Correspondingly if the cooling water disap pears it can lead to a dry contact situation. These kind of situations can contribute to failure of seals. Usually the cooling liquid in a m echanical face seal is water. At high temperatures the sliding contact becomes unstable because of cavitation in the lubrication region. The cavitation is a result of boiling of the lubricant in the contact. Th is cavitation can effect severe wear in the sliding materials. A measu ring gauge was situated quite near the sliding contact because high fr equency AE signals attenuate very quickly in boundary surfaces. The se al was tested when the sliding contact was normal and dry and also whe n the leakage was high. Also tests at high temperatures were made and the temperature region where sliding contact becomes unstable was dete rmined using temperature and AE measurement.