• 대한조선학회논문집
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• 제52권5호
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• pp.372-379
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• 2015

The blade root fillets which have strong influences on the performance of propellers in the both structural and hydrodynamic points of view, are mechanical parts for smooth connection surface with a blade and a hub. A few related researches (Sabol, 1983; Kennedy, 1997) have noted that 3T-T/3 double radius section design would be suitable for reducing Stress Concentration Factor(SCF) and increasing Cavitation Inception Speed(CIS). In this paper, it is confirmed that this compound cross-section design has come close to the optimum solution in the shape optimization standpoint so that it could protect the propeller blade under the frequent and various loading cases. On that basis, we suggest the definite and simple fillet design methodology that has the cross-section with nT-T/n compound radius and elliptic shape which could sustain the given derivatives information as well as the offsets at the boundary and all inner region of the fillet surface. In addition, the result of design is presented in form of IGES file format in order to connect with NC machine seamlessly.

• 대한조선학회논문집
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• 제47권6호
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• pp.770-775
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• 2010

As considerable interests in noise emission from the ships have been increased, control of the propeller cavitation generating vibration and radiating noise is looming large. In general, the tip vortex cavitation is first produced in case of full scale propellers, and noise levels rise dramatically from that moment. In order to reduce induced noise from the tip vortex cavitation and hence increase the cavity inception speed, we propose the mass injection method. Water injected from the propeller tip decreases rotating speed of the tip flow, and it restrains growing the tip vortex cavity. Experimental investigations of the model tests carried out in a large cavitation tunnel show that the tip vortex cavitation is effectively controled by water injection from the propeller tip.