﻿ 一种新型深水浮式平台及其系泊系统动力响应分析
 舰船科学技术  2021, Vol. 43 Issue (3): 95-101    DOI: 10.3404/j.issn.1672-7649.2021.03.019 PDF

Dynamic characteristics of a novel deep water floating platform with mooring system
DENG Xiao-kang, XIE Weng-hui, LI Yang, HAN Xu-liang
CNOOC Research Institute Co., Ltd., Beijing 100028, China
Abstract: In the present study, a novel deep water floating platform with dry tree system is investigated. The frequency-domain and time-domain analysis methods are employed to study the motion responses and mooring forces of the platform in different sea states. The numerical results are compared with experimental results to verify the numerical method in the present study. Then, the influence of the case that a mooring line is broken and the telescopic column length on the platform performance is analyzed. Results show that the novel deep water floating platform can achieve a better heave performance. And the length of the telescopic column has an effect on the heave motion of the platform. Moreover, the performance of the platform will change significantly if a mooring line is broken.
Key words: deep water floating platform     mooring system     frequency-domain analysis     time-domain analysis     motion responses     mooring forces
0 引　言

Haslum和Faltinsen通过研究发现减少运动响应主要有3种方式：1）增加平台阻尼；2）使平台垂荡固有周期远离波能范围；3）减小垂荡激励力[3]。于是，众多学者和专家通过增加平台吃水[4]、安装垂荡板[5-6]、设置双层下浮体等方法设计和研究了桁架式半潜平台[7-8]、可伸展吃水半潜式平台[7-9]、斜立柱半潜式平台[10-11]和自由悬挂固体压载舱半潜式平台[12]。大量的研究表明，这些新型半潜式平台的垂向附加质量显著增大，垂荡固有周期显著提高，垂荡运动显著减小，可满足干式采油树的使用要求。

1 基本理论 1.1 三维线性势流理论

 $\varphi = {\varphi _i} + {\varphi _d} + \sum\limits_{j = 1}^M {{\varphi _{{m_j}}}} \text{。}$ (1)
1.2 频域运动方程

 $\begin{split} &\left( {{{{m}}_{ij}} + {{ \mu} _{ij}}} \right)\mathop {{x_j}}\limits^{ \cdot \cdot } + {{ \lambda} _{ij}}\mathop {{x_j}}\limits^ \cdot + {{{c}}_{ij}}{x_j} = {f_i},i = 1,2, \cdot \cdot \cdot 6,\\ &j = 1,2, \cdot \cdot \cdot 6\text{。} \end{split}$ (2)

1.3 低频时域运动方程

 ${\left\{ {\begin{array}{*{20}{l}} {\left( {m + {\mu _{11}}} \right){{\ddot x}_1} + {\mu _{12}}{{\ddot x}_2} + {\mu _{16}}{{\ddot x}_6} + {b_{11}}{{\dot x}_1} = F_1^{wind} + F_1^{current} + F_1^{wave} + F_1^{moor}}\text{,} \\ {{\mu _{21}}{{\ddot x}_1} + \left( {m + {\mu _{22}}} \right){{\ddot x}_2} + {\mu _{26}}{{\ddot x}_6} + {b_{22}}{{\dot x}_2} = F_2^{wind} + F_2^{current} + F_2^{wave} + F_2^{moor}}\text{,} \\ {{\mu _{61}}{{\ddot x}_1} + {\mu _{62}}{{\ddot x}_2} + \left( {{I_{66}} + {\mu _{66}}} \right){{\ddot x}_6} + {b_{66}}{{\dot x}_6} = F_6^{wind} + F_6^{current} + F_6^{wave} + F_6^{moor}} \text{。} \end{array}} \right.}$ (3)

1.4 波频时域运动方程

 $\begin{split} \sum\limits_{j = 1}^6 &{\left[ {\left( {{{{M}}_{ij}} + {\mu _{ij}}} \right){{\ddot x}_j}(t) + \int_0^t {{K_{ij}}(t - \tau ){{\dot x}_j}(\tau )d\tau } + {{{C}}_{ij}}{x_j}(t)} \right]}=\\ &{F_{wi}}(t)\;\;\;i = 1,2, \cdots ,6 \text{。} \end{split}$ (4)

2 数值分析模型 2.1 DTP平台模型

 图 1 DTP平台 Fig. 1 DTP platform

2.2 系泊系统参数

 图 2 DTP平台系泊系统布置图 Fig. 2 The mooring system of DTP platform

2.3 环境工况参数

3 频域水动力分析

 图 3 DTP平台水动力模型 Fig. 3 The hydrodynamic model of DTP platform
3.1 附加质量和势流阻尼

 图 4 DTP平台附加质量 Fig. 4 The added mass of DTP platform

 图 5 DTP平台势流阻尼 Fig. 5 The potential damping of DTP platform
3.2 幅值响应函数

 图 6 DTP平台幅值响应函数 Fig. 6 The RAO of DTP platform
4 时域水动力分析 4.1 数值方法验证

 图 7 DTP平台耦合分析模型 Fig. 7 The coupling model of DTP platform

4.2 完整工况分析

4.3 破断工况分析

4.4 伸缩立柱长度影响

 图 8 具有不同伸缩立柱长度的DTP平台垂荡附加质量 Fig. 8 The added mass of DTP platform with different column lengths
5 结　语

1）在极端海况下，如若某一根锚链发生断裂，会使得平台水平运动及锚链力急速增大，而对平台垂荡运动及转动影响较小；

2）与传统半潜式平台相比，DTP平台下设下浮箱及垂荡板，下浮箱及垂荡板的存在极大地增大了平台的垂荡附加质量，从而极大地减小了平台的垂荡运动；

3）平台的纵荡运动、纵摇运动和锚链力随伸缩立柱长度增加而增大，而垂荡运动则随伸缩立柱长度增加而减小，平台垂荡运动的减小是因为伸缩立柱长度的增加，使得平台垂荡附加质量增大，从而抑制了平台的垂荡运动。

 [1] 姜哲, 谢彬, 谢文会. 新型深水半潜式生产平台发展综述[J]. 海洋工程, 2011, 29(3): 132-138. DOI:10.3969/j.issn.1005-9865.2011.03.020 [2] 罗勇, 高巍, 申辉, 等. 新型深水干树半潜平台选型及总体性能分析研究[J]. 中国造船, 2013, 54(2): 30-40. [3] HASLUM H A, FALTINSEN O M. Alternative shape of Spar platforms for use in hostile areas[C]. //Offshore Technology Conference, Huston, 1999. [4] BINDINGSBØ A U, BJØRSET A. Deep draft semi submerible[C]. //21st International Conference on Offshore Mechanics and Arctic Engineering, Oslo, 2002. [5] THIAGARAJAN K P, DATTA I, RAN A Z, et al. Influence of heave plate geometry on the heave response of classic spars[C]. //21st International Conference on Offshore Mechanics and Arctic Engineering, Oslo, 2002. [6] DOWNIE M J, GRAHAM J M R, HALL C, et al. An experimental investigation of motion control devices for truss spars[J]. .Marine Structure, 2000, 13(2): 75-90. DOI:10.1016/S0951-8339(00)00010-1 [7] MURRAY J J, YANG C K, CHEN C Y, et al. Two dry tree semisubmersible designs for ultra deep water post-katrina Gulf of Mexico[C]. //ASME 27th International Conference on Offshore Mechanics and Arctic Engineering, Estoril, 2008. [8] CHEN C Y, DING Y, MILLS T, et al. Improving the motions of a semi by the addition of heave plates[C]. //ASME 27th International Conference on Offshore Mechanics and Arctic Engineering, Estoril, 2008. [9] YANG C K, MURRAY J, NAH E, et al. An investigation of stability and workability of ESEMI under the pre-service condition in Gulf of Mexico[C]. //ASME 27th International Conference on Offshore Mechanics and Arctic Engineering, Estoril, 2008. [10] WILLIAMS N, HEIDARI H, LARGE S, et al. FourStar: a novel battered column TLP concept[C]. //17th International Offshore and Polar Engineering Conference, Lisbon, 2007. [11] WILLIAMS N, LEVERETTE S, BIAN S, et al. FourStarTM dry-tree semisubmersible development[C]. //ASME 29th International Conference on Ocean, Offshore and Arctic Engineering, Shanghai, 2010. [12] MANSOUR A M. FHS Semi: a semisubmersible design for dry tree applications[C]. //ASME 28th International Conference on Ocean, Offshore and Arctic Engineering Conference, Honolulu, 2009. [13] 谢彬, 姜哲, 谢文会. 一种新型深水浮式平台-深水不倒翁平台的自主研发[J]. 中国海上油气, 2012, 24(3): 60-65. [14] JIANG Z, XIE B, CUI W C, et al. A study on the heave performance and loads of the critical connections of a novel dry tree semisubmersible concept using numerical and experimental methods[J]. Ocean Engineering, 2016, 124: 42-53. DOI:10.1016/j.oceaneng.2016.07.039 [15] 梁宁, 黄维平, 周阳, 等. 基于抵消周期设计的干树半潜式平台水动力性能研究[J]. 中国海洋平台, 2016, 31(5): 84-92. DOI:10.3969/j.issn.1001-4500.2016.05.016