【作者】 刘文彬；

【导师】 张阿漫；

【作者基本信息】 哈尔滨工程大学 ， 船舶与海洋结构物设计制造， 2024， 博士

【摘要】 大型船舶在航行过程中常因各种意外事故导致船体结构受损,随之而来的是舱室破损进水。破损船舶的进水及抗沉问题包括动态进水过程、影响因素、船体运动响应、以及破损船舶的抗沉方法等方面,一直以来都是受到广泛关注的问题。同时,破损船舶的动态进水及抗沉是一个复杂的流固耦合动力学过程,涉及诸多学科。为此,本文在充分调研破损船舶的相关研究基础上,针对影响破损船舶的动态进水以及气垫抗沉方法的问题,基于弱可压SPH理论,结合切片法理论和数值计算技术改进了δ-SPH数值模拟算法,实现了对破损船舶进水问题以及考虑空气影响的进水问题的模拟。随后又建立了破损船舶进水舱室内气垫效应以及气垫抗沉的模型实验方法,实现了对破损舱室内气垫效应和气垫抗沉的模型实验研究。本文的研究内容旨在为船舶分舱设计以及船舶破损后的应急抗沉措施提供理论参考和技术支撑。本文基于弱可压SPH理论和刚体运动方程,结合切片法原理和数值计算技术,建立了改进的δ-SPH数值模拟方法,实现了对破损船舶舱室进水问题的模拟。计及了舱室破损位置、破口尺寸等破损特征以及舱室内障碍物的形状、尺寸、数量等结构特点的影响,分别对不同破损特征和舱室结构特点的破损舱室进水过程进行模拟。通过对比进水过程中破损舱室内进水流动特点以及模型的横向位移、垂向位移、横倾角度、横倾角速度等运动响应情况,分析了舱室破损特征和结构特点对破损船舶的动态进水过程以及船体运动响应的影响机理和规律。随后,在本文建立的改进δ-SPH数值模拟方法基础上,对舱室特征对动态进水过程的影响展开研究。本文设计并模拟了多级破损舱室的进水过程,分别讨论了水密分舱对破损模型的进水过程和运动响应的影响,以及多级舱室进水过程中的进水特点和规律。对比了破损舱室内,进水的不同漫延过程对模型运动响应产生的影响等。本文又分别模拟了不同舱室连通率的横向连通舱室和垂向连通舱室模型的进水过程,讨论了舱室连通率对进水过程的影响机理和规律。通过对比具备不同储备浮力以及多种连通舱室破损模型的进水特征,归纳了舱室连通率对进水时间的影响特性,并提出了针对连通舱室进水问题的分段研究方法。然后,针对进水舱室内气垫效应的问题,本文建立了气垫效应模型实验方法。通过对不同通气率的舱室进行破损进水实验,检测进水过程中破损舱室内气垫压强、进水深度、进水时间以及舱段模型的运动响应等,分析了气垫效应的作用机理和影响规律,讨论了舱室通气率与气垫效应的关系。为了摸清通气口形状的影响,本文又对多种分布形式的通气口进行实验,讨论了通气孔分布特点对舱室通气率的影响。利用模型实验数据,分别对准静态方法和多相流SPH方法的模拟计算结果进行验证,得出了在进水舱室气垫效应问题研究中,准静态方法的适用性和多相流SPH方法的可行性。基于上述气垫效应模型实验,本文建立了气垫抗沉实验方法。设置了实验模型的底部和舷侧两种破损状态以及破损舱室的三种通气率情况,确定了向破损舱室充气的四个充气时机,并有序改变每次气垫抗沉过程中的充气率。实时监测气垫抗沉过程中破损舱室内的气垫压强、进水深度以及进水延长时间等,分析了气垫抗沉的作用机理和效果规律,讨论了不同的充气时机和舱室通气率对气垫抗沉的影响特性,并得出了气垫抗沉随充气率的变化关系。最后,本文提出了一套可用于船舶分舱和气垫抗沉应急措施的设计方案。更多还原

【Abstract】 In the course of sailing,the hull structure of large ships is often damaged due to various accidents,followed by damage to the cabin and water flooding into the cabin.The problems of water flooding and anti-sinking of damaged ships,including water flooding process,influencing factors,hull motion response,and anti-sinking methods of damaged ships,have been widely concerned.Meanwhile,the flooding and anti-sinking of damaged ships is a complex coupled dynamic process involving many disciplines.Therefore,this paper focuses on the factors affecting the flooding process and motion response of damaged ships,the mechanism and influence law of compressed air in damaged cabins,and the air cushion anti-sinking method for damaged ships.Based on the weakly compressible SPH theory,the numerical simulation methods ofδ-SPH and multiphase flow SPH are improved,which can simulate the flooding problem of damaged ships whether considering the influence of air or not.Then,the model experiment of air cushion effect and air cushion anti-sinking in the damaged cabin is established and realized.The research content of this paper aims to provide theoretical reference and technical support for ship subdivision design and emergency anti-sinking measures after ship damage.Based on the weak compressible SPH theory and rigid body motion equation,combined with the principle of strip method and numerical computing technology,an improvedδ-SPH numerical simulation method is established to simulate the flooding problem of damaged ship cabins.The effects of the location and size of the damage opening,as well as the shape,size,and number of internal cabin barriers are considered.The flooding process of models with different damage conditions and structure characteristics is simulated.By comparing the characteristics of the flow field inside the cabin,the horizontal and vertical displacements,roll angle and the heeling angle velocity of the model during the flooding process,the influence mechanism and laws of cabin damage conditions and structure characteristics on the flooding process and ship body motion response are analyzed.Then,on the basis of the improved SPH numerical simulation method established in this paper,the effect of damaged cabin characteristics is studied,and the damaged cabin model of multi-cabin flooding is designed and simulated.The influence of watertight subdivision form on the flooding process and motion response of the damaged model,and the characteristics and rules of flooding during the multi-stage flooding process are discussed respectively.The influence of different spreading processes of inflow water on the model’s motion response is compared.This paper also simulates the flooding process of transverse and vertical connected cabin models with different cabin connectivity ratio,discusses the influence mechanism and law of cabin connectivity ratio on the flooding process,obtains the effective influence threshold of cabin connectivity ratio,and proposes the sectionalized study method for connected cabin flooding.Next,in order to study the problem of air cushion effect in damaged ships,the model experimental method of air cushion effect is established.By conducting experimental tests on the flooding process of damaged cabin models with different ventilation ratios,the air cushion pressure,inflowing water depth,flooding time,and movement response of model are detected,and the mechanism and laws of the air cushion effect are analyzed.The relationship between the ventilation ratio of the cabin and the strength of the air cushion effect is discussed.The effects of the distribution of ventilation holes on the ventilation ratio of the cabin are discussed by conducting experiments on various distribution forms of ventilation holes.The problem of air cushion effect in damaged cabins is simulated using both quasi-static methods and SPH methods,and the simulation results are verified by using data from the model experiments.The applicability of quasi-static method and the feasibility of SPH method in simulating this problem are respectively derived.Based on the above model experiment research of air cushion effect,this paper designs the model experiment of air cushion anti-sinking method of a whole ship model.The bottom and side opening of the ship model are set as two types of damage condition,and three ventilation ratios are set for the damaged cabin.Four levels of timings for filling the damaged cabin with air are formulated,and the filling rate is changed in an orderly manner during each air cushion anti-sinking process.The air cushion pressure and the water depth in the damaged cabin,as well as the delayed flooding time during the air cushion anti-sinking process are monitored.The mechanism and laws of anti-sinking by using air cushion are analyzed.The sensitivity of air cushion anti-sinking to filling timing and ventilation ratio is discussed,and the relationship between the air cushion anti-sinking effect and the filling rate is derived.Finally,this paper summarizes all the research content and provides a set of design ideas for ship cabin subdivisions and air cushion anti-sinking emergency measures.更多还原