Design Optimization of Wake Equalizing Duct Using CFD

doi:2011.25.4.42

J. Ocean Eng. Technol. > Volume 25(4); 2011 > Article

J. Ocean Eng. Technol. 2011;25(4):42-47.
DOI: https://doi.org/10.5574/KSOE.2011.25.4.042

Lee Ho-Sung,Kim Dong-Joon

Department of Naval Architecture and Marine Systems Engineering Pukyong National University,Department of Naval Architecture and Marine Systems Engineering Pukyong National University

CFD를 이용한 Wake Equalizing Duct의 최적설계

이호성,김동준

부경대학교 조선해양시스템공학과,부경대학교 조선해양시스템공학과

Keywords: Wake equalizing duct, Computational fluid dynamics, Optimum design

핵심용어: 반류균등 덕트, 전산유체역학, 최적설계

Abstract

In this paper, wake equalizing duct (WED) form optimization was carried out using computational fluid dynamics (CFD) techniques. A WED is a ring-shaped flow vane with a foil-type cross-section fitted to a hull in front of the upper propeller area. The main advantage of a WED is the power savings resulting from the uniformity of the velocity distribution on the propeller plane, a reduction in the flow separation at the aft-body, and lift generation with a forward force component on the foil section. This paper intends to evaluate these functions and find an optimized WED form for minimizing the viscous resistance and equalizing the wake distribution. In the optimization process, the study uses four WED parameters: the angle of the section, longitudinal location, and angles of the axes for the half rings against the longitudinal and transverse planes of the ship. KRISO 300K VLCC2 (KVLCC2) is chosen as an example ship to demonstrate the WED optimization. The optimization procedure uses genetic algorithms (GAs), a gradient-based optimizer for the refinement of the solution, and Non-dominated Sorting GA-II(NSGA-II) for Multiobjective Optimization. The results show that the optimized WED can reduce the viscous resistance at the expense of the uniformity of the wake distribution.