考虑液舱晃荡影响的浮式生产储油轮波浪响应研究

发布时间：2018-03-04 02:25

本文选题：FPSO　切入点：液舱晃荡　出处：《江苏科技大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着海洋油气资源开发技术的发展,浮式生产储油轮(Floating Production Storage and Offloading,FPSO)的应用越发广泛,同时它的发展还有着大型化、深水化和高安全性要求的特点。波浪中FPSO的运动激励着其内部液舱中的液体发生晃荡,使其产生较大的晃荡压力,严重时对结构产生破坏,而晃荡的液货又影响FPSO的运动,两者相互影响,是一个典型的耦合问题。在现有的研究中,对于液舱晃荡问题通常较多关注于其内部自由液面的捕捉,对于运动响应与结构强度计算问题,通常将液货固化不考虑其液舱晃荡效应。而将两者结合考虑,分析液舱晃荡对运动响应和结构响应影响的研究还相对较少,需要进一步研究。本文基于三维频域与时域势流理论,对FPSO采用线性与弱非线性理论,对液舱晃荡采用线性理论,并采用新的水动力-结构载荷传递方法,在不考虑系泊系统的影响下,就液舱晃荡对FPSO运动响应与结构响应的影响问题进行如下几个方面的工作:1)围绕船舶在波浪中的运动与载荷预报、液舱晃荡问题、液舱晃荡与船舶的耦合这三个方面的研究,阅读大量国内外文献,对之前的研究进展进行了较为全面的回顾与综述;2)利用波浪理论、船舶在波浪中运动的势流理论和液舱内流场的势流理论,建立了船舶与液舱晃荡的耦合运动方程,并介绍了其数值解法,然后阐述了基于水动力-结构模型的载荷传递方法;3)基于线性频域势流理论,采用Hydro STAR软件,对一艘实验FPSO在不同载液率、不同浪向下的频域运动响应进行计算,通过与实验结果对比,验证计算方法的有效性,并分析不同载液率工况时,液舱晃荡对FPSO运动响应的影响规律。4)利用时域势流理论,通过HOMER软件,对FPSO采用弱非线性理论,对液舱晃荡采用线性理论,对FPSO在多个典型波浪频率下的运动响应和载荷进行时域计算,分析不同时刻液舱晃荡对FPSO的运动和载荷的影响规律,并讨论不同时刻液舱内的晃荡压力。5)建立结构有限元模型,应用水动力-结构载荷传递方法,将FPSO所受的波浪和液舱载荷传递给结构模型并利用HOMER软件中的Nastran模块进行结构应力计算,探究不同时刻液舱晃荡对FPSO整体和局部结构应力的影响规律,分析应力较大的区域并提出改进意见。
[Abstract]:With the development of offshore oil and gas resources exploitation technology, floating Production Storage and offloading FPSOs are more and more widely used. The motion of FPSO in the wave stimulates the liquid in its internal tank to wobble, causing it to produce a large sloshing pressure, which can destroy the structure seriously, and the sloshing liquid and cargo affect the movement of FPSO. The interaction between the two is a typical coupling problem. In the existing research, the sloshing problem of tank is usually focused on the capture of the free liquid surface, the motion response and the calculation of the structural strength. Generally, the tank sloshing effect is not considered when the liquid cargo is solidified. However, the research on the effect of tank sloshing on the motion response and structural response is relatively rare. Based on the theory of potential flow in frequency domain and time domain, linear and weakly nonlinear theories are adopted for FPSO, linear theory for sloshing of tank is adopted, and a new method of hydrodynamic and structural load transfer is adopted. Without considering the influence of mooring system, this paper deals with the influence of tank sloshing on FPSO motion response and structural response in the following aspects: 1) the prediction of ship motion and load in waves, and the sloshing of tank. In this paper, the coupling of tank sloshing and ship is studied, a large number of domestic and foreign literatures are read, and the previous research progress is comprehensively reviewed and summarized. (2) the wave theory is used. The potential flow theory of ship motion in waves and the potential flow theory of tank flow field are used to establish the coupled motion equation of ship and tank sloshing, and its numerical solution is introduced. Then, the load-transfer method based on hydrodynamic structure model is described. Based on the theory of linear frequency-domain potential flow and Hydro STAR software, the motion response of an experimental FPSO in frequency domain with different liquid loading rates and downward waves is calculated. By comparing with the experimental results, the validity of the calculation method is verified, and the influence of tank sloshing on FPSO motion response under different loading rate conditions is analyzed. (4) using the time-domain potential flow theory and HOMER software, the weakly nonlinear theory is applied to FPSO. The linear theory is used to calculate the motion response and load of FPSO at several typical wave frequencies in time domain. The influence of sloshing on the motion and load of FPSO at different times is analyzed. The sloshing pressure in tank at different times is discussed. 5) the finite element model of the structure is established, and the method of hydrodynamic and structural load transfer is applied. The wave and tank loads of FPSO are transferred to the structural model and the structural stress is calculated by using the Nastran module in the HOMER software. The effects of tank sloshing on the overall and local structural stresses of FPSO at different times are investigated. Analyze the area with high stress and put forward some suggestions for improvement.
【学位授予单位】：江苏科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U661.3

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