船体表面附着的海洋生物为什么会明显增加船舶油耗?
Why does biofouling on a hull noticeably increase a ship's fuel consumption?
藤壶与黏液膜使船体表面粗糙度增大,湍流边界层内摩擦阻力上升,而常规航速下摩擦阻力约占总阻力的七成。实船测量表明仅一层薄黏液膜即可使燃油消耗增加一成以上,因此船东依靠防污涂料、水下清洗和坞修周期来控制污底。
Barnacles and slime films raise hull roughness, increasing frictional resistance inside the turbulent boundary layer, which accounts for roughly seventy percent of total resistance at service speed. Full-scale measurements show that even a thin slime layer can push fuel consumption up by more than ten percent, so operators fight fouling with antifouling coatings, underwater cleaning and dry-docking intervals.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
A. F. Molland 等《Ship Resistance and Propulsion》(剑桥大学出版社)阻力章节中的粗糙度增量数据
A. F. Molland, S. R. Turnock & D. A. Hudson, Ship Resistance and Propulsion, Cambridge University Press, roughness-addition data in the resistance chapter
独立核验依据 · Independent verification: 核验依据 1 ISBN 9781316494196 (2017)
#污底 #摩擦阻力
螺旋桨叶背空化为什么同时损害推进效率并侵蚀桨叶表面?
Why does suction-side cavitation on a propeller degrade propulsive efficiency and erode the blade surface at the same time?
叶背与导边局部压力降到饱和蒸气压以下时水体汽化成泡,气泡被扫入高压区后溃灭,微射流反复锤击表面造成剥蚀、噪声与轴系激振。空泡还改变叶剖面的有效攻角与升力分布,使推力下降而扭矩几乎不变,设计中通过增加浸深、加大盘面比和侧斜叶片布置推迟空化发生。
Where local pressure on the suction side or leading edge falls below vapour pressure, the water flashes into bubbles that collapse upon reaching higher-pressure regions, and the resulting microjets repeatedly hammer the surface, causing erosion, noise and shaft vibration. Cavitation also distorts the effective angle of attack and lift distribution of blade sections, so thrust drops while torque hardly changes; designers delay onset through greater immersion, larger expanded area ratios and skewed blades.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
J. S. Carlton《Marine Propellers and Propulsion》(Butterworth-Heinemann,第4版)空化章节
J. S. Carlton, Marine Propellers and Propulsion, 4th ed., Butterworth-Heinemann, cavitation chapter
独立核验依据 · Independent verification: 核验依据 1 ISBN 9780081003749 (2018)
#空化 #汽蚀剥蚀
船舶螺旋桨设计中怎样抑制空化的发生，空化一旦形成会带来哪些危害？
How do ship propeller designs suppress cavitation onset, and what damage follows once it appears?
叶背局部压力降到饱和蒸气压以下即产生气泡，气泡滑入高压区溃灭时会剥蚀金属、辐射强烈噪声并蚕食有效推力。设计中通过限制叶梢负荷、增大侧斜和纵倾来摊平吸力峰，同时匹配足够的浸深与较低转速，保证盘面上方来流静压处处高于汽化阈值。
Cavitation starts wherever local blade-surface pressure falls below saturated vapour pressure; collapsing bubbles erode metal, radiate harsh noise and eat into useful thrust. Designers flatten suction peaks by capping tip loading and adding skew plus rake, then pair sufficient immersion depth with lower shaft speed so static pressure across the disc stays above the vaporization threshold everywhere.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
盛振邦、刘应中《船舶原理》，上海交通大学出版社，螺旋桨推进篇
J. S. Carlton, Marine Propellers and Propulsion, Butterworth-Heinemann, cavitation chapters
独立核验依据 · Independent verification: 核验依据 1 ISBN 9780081003749 (2018)
#螺旋桨空化 #叶片载荷