﻿ 南海岛礁极浅水下半潜平台锚泊系统数值模拟探究
 舰船科学技术  2017, Vol. 39 Issue (1): 68-73 PDF

Numerical investigation of mooring system for a semi-submersible in ultra-shallow water of south china sea reefs area
WANG Yong-heng, WANG Lei, WANG Xue-feng, XU Sheng-wen
State Key Laboratory of Ocean Engineering, Shanghai Jiaotong University, Shanghai 200240, China
Abstract: Mooring positioning system is one of the key technologies for marine structures, and it has high security, high positioning accuracy, relatively low economic cost, so it is widely used. It is an essential technology ocean development process. In this paper, designed a mooring system for a semi-submersible platform in ultra-shallow water of South China Sea reefs area and analyzed platform positioning accuracy. Considering the complex coastal ocean environment and ultra-shallow water, asymmetric arrangement mooring system is usually adopted. In order to increase bottom friction, chain is decorated a lot of weight.
Key words: ｍooring system     positioning accuracy     complex terrain     ultra-shallow water
0 引言

1 平台运动响应理论 1.1 坐标系

1.2 平台时域运动方程

 $\begin{array}{l} \left( {M + m} \right){\ddot x}\left( t \right) + \int_{ - \infty }^t {{K}\left( {t - \tau } \right)} {{\dot x}}\left( t \right){\rm{d}}\tau + C{x}\left( t \right) = \\ {F^{F - K}} + {\rm{ }}{F^D} + {\rm{ }}{F^w} + {\rm{ }}{F^C} + {\rm{ }}{F^{sn}}\left( t \right) + {\rm{ }}{F^m}\left( t \right)。 \end{array}$ (1)

FF-K FD 合称为一阶波浪力Fw Fw 可根据 Cummins[11]提出的时域与频域波浪力的卷积关系计算：

 $\left\{ {\begin{array}{*{20}{l}} {{F_{wi}}\left( t \right) = \int_0^t {h_i^1\left( {t - \tau } \right)} {\rm{d}}\tau },\\ {h_i^1\left( t \right) = \frac{1}{\pi }\int_0^\infty {H_i^1\left( \omega \right){e^{i\omega t}}{\rm{d}}\omega } }。 \end{array}} \right.$ (2)

 ${K_{ij}}\left( t \right) = \frac{2}{\pi }\int_0^\infty {{ \lambda _{ij}}} \left( \omega \right)\cos \left( {\omega t} \right){\rm{d}}\omega,$ (3)

 ${m_{ij}} = {\mu _{ij}}({\omega _0}) + \frac{1}{{{\omega _0}}}\int_0^\infty {{K_{ij}}(t)\sin ({\omega _0}t){\rm{d}}t}。$ (4)

 ${F^w} = 0.611v_k^2{c_h}{c_s}A,$ (5)

 ${F^c} = 0.5\rho {C_D}{u^2}A$ (6)

 图 1 锚索的悬垂线 Fig. 1 Catenary of anchor cable

 \begin{aligned} \frac{{l - s}}{h} = \mathop {\left( {2q + 1} \right)}\nolimits^{\frac{1}{2}} - q\mathop {\cosh }\nolimits^{ - 1} \left( {\frac{{q + 1}}{q}} \right) =\\ \quad\mathop {\left( {2t - 1} \right)}\nolimits^{\frac{1}{2}} - \left( {t - 1} \right)\mathop {\cosh }\nolimits^{ - 1} \left( {\frac{t}{{t - 1}}} \right)。 \end{aligned} (7)

2 锚泊系统设计及计算

2.1 平台附加质量和阻尼系数

 图 2 附加质量系数 Fig. 2 Added mass coefficient

 图 3 势流阻尼系数 Fig. 3 Damping coefficient

2.2 设计工况和环境载荷

2.3 系泊系统设计

2.4 极浅水锚泊系统布置

 图 4 锚链分布 Fig. 4 Mooring chain distribution
3 平台时域模拟结果分析 3.1 六自由度运动时历

1）工作海况

 图 5 工作海况纵荡，横荡，垂荡运动时历 Fig. 5 Operation condition surge, sway, heave time history

 图 6 工作海况横摇，纵摇，首摇运动时历 Fig. 6 Operation condition roll, pitch, yaw time history

2）生存海况

 图 7 生存海况纵荡，横荡，垂荡运动时历 Fig. 7 Survival condition surge, sway, heave time history

 图 8 生存海况横摇，纵摇，首摇运动时历 Fig. 8 Survival condition roll, pitch, yaw time history

3.2 导缆孔处锚链张力时历分析

 图 9 生存海况6号锚链张力 Fig. 9 Force of line 6 in survival condition

 图 10 生存海况7号锚链张力 Fig. 10 Force of line 7 in survival condition

 图 11 工作海况6号锚链张力 Fig. 11 Operation condition line 6 force

 图 12 工作海况7号锚链张力 Fig. 12 Operation condition line 7 force

3.3 锚点处锚抓力统计结果分析

4 结语

 [1] 吴德烽, 杨国豪. 船舶动力定位关键技术研究综述[J]. 舰船科学技术 , 2014, 36 (7):1–6. WU De-feng, YANG Guo-hao. Review on key techniques for ship dynamic positioning system[J]. Ship Science and Technology , 2014, 36 (7) :1–6. [2] 王世圣, 等. 3 000米深水半潜式钻井平台运动性能研究[J]. 中国海上油气 , 2007, 19 (4):277–280, 284. WANG Shi-sheng, et al. Review on key techniques for ship dynamic positioning system[J]. Study on motion performance of 3000 metersdeep-water semi-submersible drilling platform , 2007, 19 (4) :277–280, 284. [3] 刘海霞. 深海半潜式钻井平台的重量控制探述[J]. 中国海洋平台 , 2011 (06). LIU Hai-xia. Weight Control of Deepwater Semi-submersible Drilling Unit[J]. Weight control of deepwater semi-submersible drilling unit , 2011 (06) . [4] 张峰, 王磊, 李勇跃. 锚泊辅助动力定位系统单缆失效影响研究[J]. 海洋工程 , 2012 (03):P29–34. ZHANG Feng, WANG Lei, LI Yong-yue. Research on the impact of one line failure for a mooring assisted dynamic positioning system[J]. Research on the impact of one line failure for a mooring assisted dynamic positioning system , 2012 (03) :P29–34. [5] JOHANNING L, SMITH G. H, WOLFRAM J. Measurements of static and dynamic mooring line damping and their importance for floating WEC devices[J]. Ocean Engineering , 2007, 34 (14-15) :1918–1934. DOI: 10.1016/j.oceaneng.2007.04.002 [6] 李璐. Truss Spar和半潜式平台的水动力及运动性能对比研究 [D]. 大连: 大连理工大学, 2010. [7] [8] 苏一华, 杨建民, 肖龙飞. 深海单柱式平台及其系泊系统的截断水深模型试验[J]. 上海交通大学学报 , 2007, 41 (9):1454–1459. SU Yi-hua, YANG Jian-min, XIAO Long-fei. The Experiment of a Deepwater Spar and Its Mooring System at Truncated Water Depth[J]. Journal of Shanghai Jiaotong University , 2007, 41 (9) :1454–1459. [9] 亓俊良, 龚玉林, 杨贵强. 系泊锚链配重链替代配重块工程实践[C]//. 2012年度海洋工程学术会议2012: 厦门. [10] 刘应中, 缪国平. 船舶在波浪中的运动理论[M]. 上海: 交通大学出版社, 1987. [11] CUMMINS W E. The impulse response function and ship motions[J]. Schiffstechnic , 1962 (9) :101–109. [12] 童波, 杨建民, 李欣. 深水半潜平台悬链线式系泊系统藕合动力分析[J]. 中国海洋平台. [13] 吴宋仁. 海岸动力学[M]. 北京: 人民交通出版社, 2004. Wu Songren. Coastal Hydrodynamics[M]. Beijing: China Communications Press, 2004. [14] 潘斌. 移动式平台设计[M]. 上海: 上海交通大学出版社. 1995. [15] 浮式结构定位系统的设计与分析规范[S]. [16] 童波. 半潜式平台系泊系统型式及其动力特性研究[D]. 上海：上海交通大学,2009. [17] Nuno Fonseca Ricardo Pascoal, T. M. R. D., Design of a mooring system with synthetic ropes for the FLOW wave energy converter. 2009. [18] 马鉴恩, 李凤来. 锚泊列阵的设计与研究[J]. 海洋工程 , 1996 (1):56–62. MA Jian-en Li Feng-lai. The Design and Research On Multipoint Mooring System[J]. The design and research on multipoint mooring system , 1996 (1) :56–62. [19] 唐尧. 船舶走锚运动方式的研究[D]. 大连: 大连海事大学, 2012.