Twisted thread에 의한 보텍스 캐비테이션 초생지연
Vortex Cavitation Inception Delay by Attaching a Twisted Thread
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Tip vortex cavitation (TVC) is important for naval ships and research vessels that require raising the cavitation inception speed tomaximum possible values. The concepts for alleviating the tip vortex are summarized by Platzer and Souders (1979), who carried out athorough literature survey. Active control of TVC involves the injection of a polymer or water from the blade tip. The main effect of suchmass injection (both water and polymer solutions) into the vortex core is an increase in the core radius, consequently delaying TVCinception. However, the location of the injection port needs to be selected with great care in order to ensure that the mass injection iseffective in delaying TVC inception. In the present study, we propose a semi-active control scheme that is achieved by attaching athread at the propeller tip. The main idea of a semi-active control is that because of its flexibility, the attached thread can be suckedinto the low-pressure region closer to the vortex core center. An experimental study using a scale model was carried out in thecavitation tunnel at the Seoul National University. It was found that a flexible thread can effectively suppress the occurrence of TVCunder the design condition for a model propeller.
Abstract
Tip vortex cavitation (TVC) is important for naval ships and research vessels that require raising the cavitation inception speed tomaximum possible values. The concepts for alleviating the tip vortex are summarized by Platzer and Souders (1979), who carried out athorough literature survey. Active control of TVC involves the injection of a polymer or water from the blade tip. The main effect of suchmass injection (both water and polymer solutions) into the vortex core is an increase in the core radius, consequently delaying TVCinception. However, the location of the injection port needs to be selected with great care in order to ensure that the mass injection iseffective in delaying TVC inception. In the present study, we propose a semi-active control scheme that is achieved by attaching athread at the propeller tip. The main idea of a semi-active control is that because of its flexibility, the attached thread can be suckedinto the low-pressure region closer to the vortex core center. An experimental study using a scale model was carried out in thecavitation tunnel at the Seoul National University. It was found that a flexible thread can effectively suppress the occurrence of TVCunder the design condition for a model propeller.
참고문헌 (10)
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