Development of a method to estimate fluctuating pressure on ship stern based on bubble dynamics and construction of a comprehensive optimization system for propeller design

Research Project

Project/Area Number	18K04584
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Review Section	Basic Section 24020:Marine engineering-related
Research Institution	Kyushu University
Principal Investigator	ANDO JUN 九州大学, 工学研究院, 教授 (60211710)
Project Period (FY)	2018-04-01 – 2021-03-31
Project Status	Completed (Fiscal Year 2020)
Budget Amount *help	¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000) Fiscal Year 2020: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000) Fiscal Year 2019: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000) Fiscal Year 2018: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Keywords	舶用工学 / プロペラ / キャビテーション / 気泡力学 / 船尾変動圧力 / プロペラ翼強度
Outline of Final Research Achievements	A method for solving a multi-objective optimization problem with cavity area and propeller efficiency as objective functions was developed, and its validity was confirmed by model tests. Model tests of an improved propeller, which was originally designed for a general cargo ship, showed that the propeller efficiency was improved by about 2% around the design point and that the fluctuating pressure due to cavitation was reduced. A calculation method was developed to estimate the cavity volume, which is strongly correlated with the fluctuating pressure, in a short time. This method, which is based on bubble dynamics to estimate the shape of cavitation on a two-dimensional blade in steady uniform flow, was applied to propeller blades. The calculated cavity volume on Seiun-Maru-I propellers in wake agreed well with experimental results.
Academic Significance and Societal Importance of the Research Achievements	船舶の推進性能の分野においては二酸化炭素排出量削減のため、船舶の省エネ化実現の要となる高性能プロペラの設計の重要性が一段と増している。プロペラの最適設計は、船尾伴流中でプロペラ翼面上に発生するキャビテーションによって誘起される船尾変動圧力に配慮して行われる。本研究においては、プロペラ効率および変動圧力と相関のあるキャビティ面積を目的関数とするプロペラ翼形状の多目的最適化計算法ならびに変動圧力と強い相関のあるキャビティ体積を短時間で推定する計算法を開発した。本研究成果により、より高性能なプロペラの設計が可能となり、船舶からの二酸化炭素排出量削減が期待される。