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系統識別號 U0026-1708202015380000
論文名稱(中文) 以CFD改善JBC散裝貨船船艉導罩的節能效果
論文名稱(英文) Improvement of Energy Saving Effect for the Stern Duct on JBC Bulk Carrier by using CFD
校院名稱 成功大學
系所名稱(中) 系統及船舶機電工程學系
系所名稱(英) Department of Systems and Naval Mechatronic Engineering
學年度 108
學期 2
出版年 109
研究生(中文) 張晉瑋
研究生(英文) Chin-Wei Chang
學號 P16071062
學位類別 碩士
語文別 中文
論文頁數 75頁
口試委員 口試委員-方銘川
指導教授-吳炳承
口試委員-陳建宏
口試委員-辛敬業
中文關鍵字 導罩  散裝貨輪 
英文關鍵字 OpenFOAM  CFD  JBC 
學科別分類
中文摘要 本研究在不考慮螺槳作用下改良原本配置在JBC (Japan Bulk Carrier) 散裝貨船船艉的導罩。目標是設計出比原導罩0.6%節能效果更為突出的節能裝置形狀,也就是減少船殼總阻力。該導罩的原始設計是一軸對稱、攻角20.06度的翼形截面 (NACA4420)。
研究方法是使用OPENFOAM對JBC進行船體周圍黏性流場與自由液面CFD (Computational Fluid Dynamics) 模擬,並與實驗EFD (Experimental Fluid Dynamics)做比較。在將模擬與實驗做比較得到可信的OPENFOAM設定後,將此設定應用到設計船艉導罩的研究。
建立網格為CFD重點。在固定建立網格的參數與條件後,我們在模擬延伸變化的幾何形狀時便能確保不同網格之間的完整與一致性,進行後續艉跡流比較時才有可信度的基準。由於EFD成本高且耗時,本研究將在沒有EFD可以比對的情況下先以CFD設計新型的導罩。我們將使用兩套互相有關聯的網格對原本的導罩進行模擬、與EFD比對後,建立起可信的模擬後,延伸並應用到新設計的導罩。本研究將針對設計導罩模擬出來的艉跡流進行分析。由於網格建立時已考慮其共同性,不同導罩對流場造成的差異將可明顯地顯示出來。
將OPENFOAM與EFD對JBC的結果進行分析,經由阻力係數、艉跡流與興波結果比較,OPENFOAM成功地執行了JBC的CFD阻力試驗。與EFD比較過後CFD網格分為有無局部加密兩套網格,將這兩套網格更換並設計其中的節能裝置,模擬後分析此新設計導罩的節能效果可以到達2.33%與2.49%之間。
英文摘要 The goal of this study is to improve the duct which is installed in the stern of JBC (Japan Bulk Carrier) and generate its energy-saving effect higher than the original one, i.e. 0.6%. The original design of the duct is an axisymmetrical foil section with an angle of attack of 20.06 degrees.
The grid construction is the particularly important pre-processing of CFD. After finding the appropriate parameters and conditions to generate the mesh, we continuously used the setting. By this way, the integrity and consistency can be ensured among the different meshes when extending to the other desired geometry for the simulation.
Due to the high cost and time-consuming of EFD, this study will design a new duct by CFD method without EFD data. First, two sets of grids based on the related grid construction setting were used to simulate the ship resistance test with and without the original duct, and then compared the results with EFD. This procedure would establish a reliable simulation method, and then extend and apply the simulation method to the newly designed duct. In this study, the stern flow is analyzed as well. Since the grids were established by the same setting and construction method, the influence of grid building to CFD results is negligible. In other words, the grid dependency is satisfied. Therefore, we can observe clearly the difference caused by different duct to the flow field and resistance.
By analyzing the results of JBC with OPENFOAM and EFD, comparison of resistance value, stern wake velocity distribution and wave-making pattern were conducted. After comparing with EFD, two sets of CFD grid were selected with or without local refinement to design the duct. The computational domain, boundary condition, grid construction setting, and the hull geometry input were kept the same. Only difference is to change the geometry input of the energy-saving device. The simulation results show that the energy-saving effect of this new duct can reach between 2.33% and 2.49%.
論文目次 中文摘要 I
EXTEND ABSTRACT II
致謝 VII
目錄 VIII
表目錄 X
圖目錄 XI
第1章 緒論 1
1.1 研究背景 1
1.2 研究目的 1
1.3 文獻回顧 1
第2章 CFD模擬方法 4
2.1 統御方程式 4
2.2 計算域尺寸大小 6
2.3 計算域邊界條件 7
2.4 JBC網格建立 8
2.4.1 無局部加密無導罩網格建立 10
2.4.2 無局部加密有導罩網格建立 14
2.4.3 局部加密無導罩網格建立 18
2.4.4 局部加密有導罩網格建立 23
2.4.5 結論: JBC網格建立 27
第3章 原JBC的CFD阻力試驗 29
3.1 阻力係數驗證與確認 32
3.1.1 驗證與確認理論 32
3.1.2 無局部加密有無導罩 33
3.1.3 局部加密有無導罩 34
3.2 CFD細部流場分析 35
3.2.1 艉跡流流速分布 35
3.2.2 有無局部加密網格艉跡流流速分析 43
3.3 結論: 原JBC之CFD分析 48
第4章 以CFD改良導罩設計 49
4.1 導罩設計方法 50
4.2 導罩網格建立 51
4.3 CFD阻力係數結果 54
4.4 7.06度導罩之網格獨立性分析 57
4.5 不同導罩間阻力與艉跡流比較 58
4.6 導罩設計對艉跡流的細部影響 62
4.7 結論: 以CFD設計導罩 68
第5章 總結論 69
附錄 70
船體與興波波高 70
參考文獻 75

參考文獻 Bertram, V, “Practical Ship Hydrodynamics,” Butterworth-Heinemann, 2000.

Çelik, Fahri. “A numerical study for effectiveness of a wake equalizing duct,” Ocean Engineering, Vol. 34, No. 16, pp 2138-2145, 2007.

Furcas, F., Vernengo, G., Villa, D., & Gaggero, S., “Design of Wake Equalizing Ducts using RANSE-based SBDO,” Applied Ocean Research, Vol. 97, 102087, pp. 1-17, 2020.

Guiard, T., & Leonard, S, “The Becker Mewis Duct®-Challenges in Full-Scale Design and new Developments for Fast Ships,” 3rd international symposium on marine propulsors, Launceston. 2013.

Larsson L, Stern F, Visonneau M, Hino T, Hirata N, Kim, J. (editors), “Proceedings, Tokyo 2015 Workshop on CFD in Ship Hydrodynamics, NMRI (National Maritime Research Institute),” Japan, 2015.

Maasch, M., Mizzi, K., Atlar, M., Fitzsimmons, P., & Turan, O., “A generic wake analysis tool and its application to the Japan Bulk Carrier test case,” Ocean Engineering, Vol.171, pp.575-589, 2019.
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