함정용 패키지 에어콘 응축기 핀튜브(Cu-Ni 70/30) 누설파괴 원인 분석

• Published in: Biuletyn Uniejowski Vol. 49; no. 5; pp. 439 - 446
• Main Authors: 박형훈(Hyoung Hun Park), 황양진(Yang Jin Hwang), 이규환(Kyu Hwan Lee)
• Format: Journal Article
• Language: Korean
• Published: 한국표면공학회 2016
• Subjects: 기계공학; Cu-Ni alloy; Crevice corrosion; Erosion corrosion; Heat exchanger; Fin tube; Sea water
• ISSN: 1225-8024; 2299-8403; 2288-8403
• DOI: 10.5695/JKISE.2016.49.5.439

In 2015, a fin tube (Cu-Ni 70/30 alloy) of package type heat exchanger for navy vessel was perforated through the wall which led to refrigerant leakage. This failure occurred after only one year since its installation. In this study, cause of the failure was determined based on available documents, metallographic studies and computational fluid dynamics simulation conducted on this fin tube. The results showed that dimensional gap between inserted plastic tube and inside wall of fin tube is the cause of the swirling turbulent stream of sea water. As a result of combination of swirling turbulence and continuing collision of hard solid particles in sea water, erosion corrosion has begun at the end of inserted plastic tube area. Crevice corrosion followed later in the crevice between the outer wall of plastic tube and inner wall of fin tube. It was found that other remaining tubes also showed the same corrosion phenomena. Thorough inspection and prompt replacement will have to be accomplished for the fin tubes of the same model heat exchanger.