波浪载荷作用下海洋储油平台液体晃荡仿真模拟
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摘要
液舱晃荡问题常常存在于装有液容器的运载工具或工程结构物中,例如船舶的液货舱、燃油舱以及海上储油罐等。随着石油开发力度的不断加大,出现了导管架储油平台等,因此,导管架储油平台的储油舱内也存在液体晃荡问题。当液舱的激励频率与舱内液体固有振动频率相近的时候,液体对舱壁结构产生强烈的冲击力,长时间作用会损坏舱壁结构。所以,液体晃荡载荷的分析及其对舱壁结构的作用成为导管架储油平台研发、设计时需考虑的问题之一。
晃荡问题是非常复杂的液体流动现象,它具有很强的非线性和随机性特征,是典型的流固耦合问题。影响晃荡的因素很多,如:液舱的形状及尺寸、内部构件、液体装载率、液体属性等。本文研究的主要内容是通过得到导管架储油平台在波浪中的响应,以此作为激励,运用LS-DYNA程序,对导管架储油平台的储油舱液体晃荡情况进行仿真模拟,并讨论了不同装载率、不同激励频率等对液体晃荡的影响,主要工作内容如下:
首先,本文阐述了研究晃荡的三种方法,并讨论了它们的优缺点,从流体运动方式的描述、控制方程的离散以及自由液面的追踪这三个方面详细阐述了数值模拟方法的原理。重点讨论了基于有限差分法的晃荡分析的原理、步骤及响应的特点。
其次,阐述了利用半经验半理论的莫里森方程及Airy线性波理论推导出线性化波浪力力谱,然后通过动力响应分析得到导管架储油平台的最大位移响应,以此作为晃荡数值模拟的激励条件。
最后,利用LS-DYNA分析了导管架储油平台液舱不同装载率水平下的晃荡,得到了晃荡动压力时程曲线、流体表面速度矢量图及自由表面波动图,讨论了不同的激励频率对晃荡的影响;并分析了晃荡动压力及温度对舱壁结构的作用,得到了晃荡应力及温度应力的量级。
Liquid tank sloshing is often existed in vehicles and structures which are equipped with liquid containers, such as the liquid cargo tanks, fuel oil tanks and the ocean oil storage tanks. For the reason of the oil drilling developed rapidly, there are more and more oil storage jacket platforms, which also have liquid sloshing problems in the oil storage tanks. When the excitation frequency of liquid container closes to the nature frequency of liquid, the liquid produces intense impulse forces to the bulkhead structure and even damages to the structure by the long time action. Therefore, the liquid tank sloshing load analysis and its effect to the hull structure is one of the problems to take into account in the research and design of the oil storage jacket.
Sloshing is a very complex phenomenon of flow with a high degree of nonlinearity and randomness, and is a typical problem of fluid and structure coupling. The intensity of sloshing depends on many factors, such as compartment forms, internal components, filling radios, liquid properties and so on. The main contents of this paper is to first calculate the oil storage jacket platform response to waves, and then simulate sloshing phenomenon of the oil jacket platform based on this stimulation by use of LS-DYNA, and then discuss the effect of sloshing due to different filling ratios, different excitation frequencies and different forms of the internal tank structure. The main works of this paper are as following:
Firstly, introduced three basic methods of liquid sloshing study, and discussed their advantages and disadvantages. Elaborated the principal of numerical simulation from the description of fluid movement, the dispersal of control equations and the tracking of free surface. The discussion focuses on the principal steps and related characteristics of the sloshing analysis based on the finite difference method.
Secondly, introduced the spectrum of linear wave force deduced through semi-theoretical semi-empirical formula of Morison and Airy wave theory, and obtained the maximum displacement response through dynamic response analysis of the oil storage jacket platform as the excitation in the numerical simulation of sloshing.
Finally, analyzed the sloshing load under different filling ratios by the use of LS-DYNA and obtained sloshing dynamic pressure time history curve, velocity vector of fluid surface and the free surface fluctuation. Then the paper discussed the effect of sloshing due to different excitation frequencies. What's more, the sloshing dynamic pressure and temperature effect caused to hull structure is considered and the sloshing and temperature stress magnitude is obtained.
晃荡问题是非常复杂的液体流动现象,它具有很强的非线性和随机性特征,是典型的流固耦合问题。影响晃荡的因素很多,如:液舱的形状及尺寸、内部构件、液体装载率、液体属性等。本文研究的主要内容是通过得到导管架储油平台在波浪中的响应,以此作为激励,运用LS-DYNA程序,对导管架储油平台的储油舱液体晃荡情况进行仿真模拟,并讨论了不同装载率、不同激励频率等对液体晃荡的影响,主要工作内容如下:
首先,本文阐述了研究晃荡的三种方法,并讨论了它们的优缺点,从流体运动方式的描述、控制方程的离散以及自由液面的追踪这三个方面详细阐述了数值模拟方法的原理。重点讨论了基于有限差分法的晃荡分析的原理、步骤及响应的特点。
其次,阐述了利用半经验半理论的莫里森方程及Airy线性波理论推导出线性化波浪力力谱,然后通过动力响应分析得到导管架储油平台的最大位移响应,以此作为晃荡数值模拟的激励条件。
最后,利用LS-DYNA分析了导管架储油平台液舱不同装载率水平下的晃荡,得到了晃荡动压力时程曲线、流体表面速度矢量图及自由表面波动图,讨论了不同的激励频率对晃荡的影响;并分析了晃荡动压力及温度对舱壁结构的作用,得到了晃荡应力及温度应力的量级。
Liquid tank sloshing is often existed in vehicles and structures which are equipped with liquid containers, such as the liquid cargo tanks, fuel oil tanks and the ocean oil storage tanks. For the reason of the oil drilling developed rapidly, there are more and more oil storage jacket platforms, which also have liquid sloshing problems in the oil storage tanks. When the excitation frequency of liquid container closes to the nature frequency of liquid, the liquid produces intense impulse forces to the bulkhead structure and even damages to the structure by the long time action. Therefore, the liquid tank sloshing load analysis and its effect to the hull structure is one of the problems to take into account in the research and design of the oil storage jacket.
Sloshing is a very complex phenomenon of flow with a high degree of nonlinearity and randomness, and is a typical problem of fluid and structure coupling. The intensity of sloshing depends on many factors, such as compartment forms, internal components, filling radios, liquid properties and so on. The main contents of this paper is to first calculate the oil storage jacket platform response to waves, and then simulate sloshing phenomenon of the oil jacket platform based on this stimulation by use of LS-DYNA, and then discuss the effect of sloshing due to different filling ratios, different excitation frequencies and different forms of the internal tank structure. The main works of this paper are as following:
Firstly, introduced three basic methods of liquid sloshing study, and discussed their advantages and disadvantages. Elaborated the principal of numerical simulation from the description of fluid movement, the dispersal of control equations and the tracking of free surface. The discussion focuses on the principal steps and related characteristics of the sloshing analysis based on the finite difference method.
Secondly, introduced the spectrum of linear wave force deduced through semi-theoretical semi-empirical formula of Morison and Airy wave theory, and obtained the maximum displacement response through dynamic response analysis of the oil storage jacket platform as the excitation in the numerical simulation of sloshing.
Finally, analyzed the sloshing load under different filling ratios by the use of LS-DYNA and obtained sloshing dynamic pressure time history curve, velocity vector of fluid surface and the free surface fluctuation. Then the paper discussed the effect of sloshing due to different excitation frequencies. What's more, the sloshing dynamic pressure and temperature effect caused to hull structure is considered and the sloshing and temperature stress magnitude is obtained.
引文
[1]Bass R.L.,Bowles,E.B.and Cox,P.A.Liquid Dynamic Loads in LNG Cargo Tanks[J].SNAME Transactions,1980,88:103-126.
[2]Hamlin,N.A,Lou,Y K.,Maclean,W.M.,et al.Liquid sloshing in slack tanks theory,observation and experiments[J].Trans SNAME,1986,94:159-195.
[3]沈猛.基于改进VOF法的棱形液舱液体晃荡分析及应用[D].上海:工程力学系,2008.
[4]刘泽民.关于船舱中液体晃荡问题[J].哈尔滨船舶工程学院学报,1992.13(3):242-247.
[5]朱仁庆.液体晃荡及其与结构的相互作用[D].中国船舶科学研究中心:船舶与海洋结构物设计制造,2001.
[6]王家媚,张志宏,马乾初.流体力学[M].大连:大连海事大学出版社,2002.3.
[7]Donea J,Fasoli-Stellap,et al.Lagrangian and Eulerian finite element techniques for transient fluid-structure interaction problems[M],in:rrans.SMiRT-4,Paper B1/2,USA,1977,15-19.
[8]Belytschko T and Kennedy J M.Computer models for subassembly simulation[M].Nucl Engrg.Design,1978,49:17-38.
[9]Belytschko T,Kennedy J M,et al.Quasi-Eulerian finite element formulation for fluid-structure interaction[J].Pressure Vessel Technol.ASME,1980,102:82-69.
[10]Huerta A,Liu W K.Viscous flow structure interaction[J].Pressure Vessel Technol.ASME110,1988:15-21.
[11]Nitikitpaiboon C and Bathe K J.An arbitrary Lagrangian-Eulerian velocity potential formulation for flu-id-structure interaction[J].Computers and Structures,1993,47(4/5):871-891.
[12]Liu W K and Ma D C.Computer implementation aspects for fluid-structure interaction problems[J].Com-put.Meths.Appl.Mech.Engrg,1982,31:129-148.
[13]Hughes T J R,Liu W K and Zimmerman T K.Lagrangian-Eulerian finite element formulation for incompressible viscous flows,Comput,Meths.Appl Mech.Engrg.,1981,29:329-349.
[14]ZhuRenqing,WuYousheng,Incecik Atilla.Numerical simulation of liquid sloshingareview [J].Shipbuilding of China,2004,45(2):14-27.
[15]王建军,李其汉,陆明万.自由液而流体流动问题的数值分析研究[J].计算力学学报,2003.20(1).
[16]G.X.Wu,Q.W.Ma,R.Eatock.Numerical simulation of sloshing waves in a 3D tank based on a finite element method[J].Applied Ocean Research,1998,20:337-355.
[17]C.W.Hirt,A.A.Amsden,J.L.Cook.An Arbitrary Lagrangian-Eulerian Computing Method for All Flow Speeds[J].Journal of Computational Physics,1997,135:203-216.
[18]曾江红,王照林.粘性流体大幅晃动的ALE有限元模拟[J].强度与环境,1996(3):22-31.
[19]王永学.任意容器液体晃动问题的数值模拟[D].大连:大连理工大学,1989.
[20]沈国光.矩形容器内流体晃动的数值模拟[J].水动力学研究与进展,1997,Ser A 12(3):281-288.
[21]易淑群,陈九锡.高速冲头有界入水初始阶段的数值模拟[J].水动力学研究与进展,1996,Ser A 1(2):171-180.
[22]张健,方杰,范波芹.VOF方法理论与应用综述[J].水利水电科技进展,2005.25(2):67-69
[23]李谊乐,刘应中,缪国平.二阶精度的VOF自由面追踪方法及其应用[J].船舶力学,1999.3(1):45-52.
[24]OSHER S,SETHAN J A.Fronts propagating with curvature-dependent speed:algorithms based on Hamilton-Jacobi formulation[J].Journal of computation Physics,1988,79(1) 12-49.
[25]SUSSMAN M,SMEREKA D,OSHER S.A level set approach for computing solutions to incompressible two-phase flow[J].Comp.Phys.,1994,114(1):146-159.
[26]Vincenzo Armenio and Michele La Rocca.(1996).On the analysis of sloshing of water in rectangular containers:numerical study and experimental validation[J].Ocean Engrg.Vol.23 No.8,pp 705-739P.
[27]Matauura Y.,Matsumoto K(1986).On a mean to reduce excite-vibration with the sloshing in a tank.SNAJ160.
[28]Lou YK,Choi H.(1987).Spatial pressure vibrations and Three-dimensional effects on liquid sloshing loads[J].US Mar Admin Rep Ma-RD-750-87036.
[29]李裕春,时党勇等.ANSYS/LS-DYNA基础理论与工程实践[M].中国水利水电出版社,2006.
[30]黄祥鹿,陆鑫森.海洋工程流体力学及结构响应分析[M].上海:上海交通大学出版社.1992.
[31]李远林.近海结构水动力学[M].广州:华南理工大学出版社.1999.
[32]Wang Yanying.Waves and wave loads on offshore structures.Dalian Maritime University Press.2003.
[33]中国船级社.海上固定平台入级与建造规范[M].人民交通出版社,1992.
[34]Vengatesan,V.,Varyani,K.S.,Barltrop,N..An experimental investigation of hydrodynamic coefficients for a vertical truncated rectangular cylinder due to regular and random waves[J].Ocean Engineering,27(3):291-313P 2000.
[35]宋金宝,徐德伦,孙孚.计算孤立小桩柱上随机波浪力的～个线性化的Morison公式[J].海洋学报,1997,19(3):133-141.
[36]O.M.Boaghe,S.A.Billings,P.K.Stansby.Spectral analysis for nonlinear wave forces [J].Applied Ocean Research.1998,20:199-212.
[37]滕素珍.数理统计[M].大连:大连理工大学出版社,2000.
[38]Kenji Kawano,Katta Venkatamana.Dynamic response and reliability analysis of large offshore structure.Computer methods in applied mechanics and engineering[J].1999,168:255-272.
[39]刘延柱,陈文良,陈立群.振动力学[M].北京:高等教育出版社,1992.
[40]娜日萨.VLCC液舱晃荡仿真及结构强度评估方法研究[D].哈尔滨:哈尔滨工程大学,2006
[41]韩晓双.导管架海洋平台地震响应研究[D].大连:大连理工大学船舶学院,2008.
[42]Mikelis N E,Robinsen D W.Sloshing in arbitrary shaped tanks.J.of the Society of Naval Architects of Japan,1985,158:241-255.
[2]Hamlin,N.A,Lou,Y K.,Maclean,W.M.,et al.Liquid sloshing in slack tanks theory,observation and experiments[J].Trans SNAME,1986,94:159-195.
[3]沈猛.基于改进VOF法的棱形液舱液体晃荡分析及应用[D].上海:工程力学系,2008.
[4]刘泽民.关于船舱中液体晃荡问题[J].哈尔滨船舶工程学院学报,1992.13(3):242-247.
[5]朱仁庆.液体晃荡及其与结构的相互作用[D].中国船舶科学研究中心:船舶与海洋结构物设计制造,2001.
[6]王家媚,张志宏,马乾初.流体力学[M].大连:大连海事大学出版社,2002.3.
[7]Donea J,Fasoli-Stellap,et al.Lagrangian and Eulerian finite element techniques for transient fluid-structure interaction problems[M],in:rrans.SMiRT-4,Paper B1/2,USA,1977,15-19.
[8]Belytschko T and Kennedy J M.Computer models for subassembly simulation[M].Nucl Engrg.Design,1978,49:17-38.
[9]Belytschko T,Kennedy J M,et al.Quasi-Eulerian finite element formulation for fluid-structure interaction[J].Pressure Vessel Technol.ASME,1980,102:82-69.
[10]Huerta A,Liu W K.Viscous flow structure interaction[J].Pressure Vessel Technol.ASME110,1988:15-21.
[11]Nitikitpaiboon C and Bathe K J.An arbitrary Lagrangian-Eulerian velocity potential formulation for flu-id-structure interaction[J].Computers and Structures,1993,47(4/5):871-891.
[12]Liu W K and Ma D C.Computer implementation aspects for fluid-structure interaction problems[J].Com-put.Meths.Appl.Mech.Engrg,1982,31:129-148.
[13]Hughes T J R,Liu W K and Zimmerman T K.Lagrangian-Eulerian finite element formulation for incompressible viscous flows,Comput,Meths.Appl Mech.Engrg.,1981,29:329-349.
[14]ZhuRenqing,WuYousheng,Incecik Atilla.Numerical simulation of liquid sloshingareview [J].Shipbuilding of China,2004,45(2):14-27.
[15]王建军,李其汉,陆明万.自由液而流体流动问题的数值分析研究[J].计算力学学报,2003.20(1).
[16]G.X.Wu,Q.W.Ma,R.Eatock.Numerical simulation of sloshing waves in a 3D tank based on a finite element method[J].Applied Ocean Research,1998,20:337-355.
[17]C.W.Hirt,A.A.Amsden,J.L.Cook.An Arbitrary Lagrangian-Eulerian Computing Method for All Flow Speeds[J].Journal of Computational Physics,1997,135:203-216.
[18]曾江红,王照林.粘性流体大幅晃动的ALE有限元模拟[J].强度与环境,1996(3):22-31.
[19]王永学.任意容器液体晃动问题的数值模拟[D].大连:大连理工大学,1989.
[20]沈国光.矩形容器内流体晃动的数值模拟[J].水动力学研究与进展,1997,Ser A 12(3):281-288.
[21]易淑群,陈九锡.高速冲头有界入水初始阶段的数值模拟[J].水动力学研究与进展,1996,Ser A 1(2):171-180.
[22]张健,方杰,范波芹.VOF方法理论与应用综述[J].水利水电科技进展,2005.25(2):67-69
[23]李谊乐,刘应中,缪国平.二阶精度的VOF自由面追踪方法及其应用[J].船舶力学,1999.3(1):45-52.
[24]OSHER S,SETHAN J A.Fronts propagating with curvature-dependent speed:algorithms based on Hamilton-Jacobi formulation[J].Journal of computation Physics,1988,79(1) 12-49.
[25]SUSSMAN M,SMEREKA D,OSHER S.A level set approach for computing solutions to incompressible two-phase flow[J].Comp.Phys.,1994,114(1):146-159.
[26]Vincenzo Armenio and Michele La Rocca.(1996).On the analysis of sloshing of water in rectangular containers:numerical study and experimental validation[J].Ocean Engrg.Vol.23 No.8,pp 705-739P.
[27]Matauura Y.,Matsumoto K(1986).On a mean to reduce excite-vibration with the sloshing in a tank.SNAJ160.
[28]Lou YK,Choi H.(1987).Spatial pressure vibrations and Three-dimensional effects on liquid sloshing loads[J].US Mar Admin Rep Ma-RD-750-87036.
[29]李裕春,时党勇等.ANSYS/LS-DYNA基础理论与工程实践[M].中国水利水电出版社,2006.
[30]黄祥鹿,陆鑫森.海洋工程流体力学及结构响应分析[M].上海:上海交通大学出版社.1992.
[31]李远林.近海结构水动力学[M].广州:华南理工大学出版社.1999.
[32]Wang Yanying.Waves and wave loads on offshore structures.Dalian Maritime University Press.2003.
[33]中国船级社.海上固定平台入级与建造规范[M].人民交通出版社,1992.
[34]Vengatesan,V.,Varyani,K.S.,Barltrop,N..An experimental investigation of hydrodynamic coefficients for a vertical truncated rectangular cylinder due to regular and random waves[J].Ocean Engineering,27(3):291-313P 2000.
[35]宋金宝,徐德伦,孙孚.计算孤立小桩柱上随机波浪力的～个线性化的Morison公式[J].海洋学报,1997,19(3):133-141.
[36]O.M.Boaghe,S.A.Billings,P.K.Stansby.Spectral analysis for nonlinear wave forces [J].Applied Ocean Research.1998,20:199-212.
[37]滕素珍.数理统计[M].大连:大连理工大学出版社,2000.
[38]Kenji Kawano,Katta Venkatamana.Dynamic response and reliability analysis of large offshore structure.Computer methods in applied mechanics and engineering[J].1999,168:255-272.
[39]刘延柱,陈文良,陈立群.振动力学[M].北京:高等教育出版社,1992.
[40]娜日萨.VLCC液舱晃荡仿真及结构强度评估方法研究[D].哈尔滨:哈尔滨工程大学,2006
[41]韩晓双.导管架海洋平台地震响应研究[D].大连:大连理工大学船舶学院,2008.
[42]Mikelis N E,Robinsen D W.Sloshing in arbitrary shaped tanks.J.of the Society of Naval Architects of Japan,1985,158:241-255.