Twisted thread에 의한 보텍스 캐비테이션 초생지연

• Published in: 大韓造船學會 論文集 Vol. 51; no. 3; pp. 259 - 264
• Main Authors: 박상일(Sang-Il Park), 이승재(Seung-Jae Lee), 유극상(Guek-Sang You), 서정천(Jung-Chun Suh)
• Format: Journal Article
• Language: Korean
• Published: 대한조선학회 2014
• Subjects: 조선공학; Cavitation inception speed(CIS; 캐비테이션 초생속도; Model test (모형시험); 날개 끝 보텍스 캐비테이션; Cavitation tunnel(공동수조); Propeller (프로펠러); Tip vortex cavitation(TVC; Cavitation delay(캐비테이션 발생지연)
• ISSN: 1225-1143; 2287-7355

Tip vortex cavitation (TVC) is important for naval ships and research vessels that require raising the cavitation inception speed to maximum possible values. The concepts for alleviating the tip vortex are summarized by Platzer and Souders (1979), who carried out a thorough literature survey. Active control of TVC involves the injection of a polymer or water from the blade tip. The main effect of such mass injection (both water and polymer solutions) into the vortex core is an increase in the core radius, consequently delaying TVC inception. However, the location of the injection port needs to be selected with great care in order to ensure that the mass injection is effective in delaying TVC inception. In the present study, we propose a semi-active control scheme that is achieved by attaching a thread at the propeller tip. The main idea of a semi-active control is that because of its flexibility, the attached thread can be sucked into the low-pressure region closer to the vortex core center. An experimental study using a scale model was carried out in the cavitation tunnel at the Seoul National University. It was found that a flexible thread can effectively suppress the occurrence of TVC under the design condition for a model propeller.