深水网箱水下网格式锚泊系统的安装工艺

深水养殖网箱由网箱框架系统、网衣系统、锚泊系统和配套设施系统四大部分组成。其中锚泊系统是网箱在水中的根基，确保网箱系统正常运作和在高海况中不致网箱整体受力不均而损坏。     

小尺度网箱缆绳张力在波浪中的变化特性

海水养殖网箱系统主要包括网箱框架、网衣和锚泊系统.其中锚泊系统是网箱系统安全的重要保证之一,而锚泊系统设计的核心问题是系泊力,即缆绳张力问题.为了保证受风浪冲击的网箱锚泊安全,必须对锚泊的动力负荷进行分析研究.为此本研究设计了一种小尺度网箱进行试验,通过测量不同波长、波高的波浪中网箱的缆绳张力、以及波浪通过网箱前后时的平均波高及波长,对网箱缆绳张力随波长、波高的变化进行分析和研究.结果表明,波浪中缆绳张力最大张力随波高的增加而增加,且随着波浪周期的增加张力增加的趋势随波高变缓,而波浪的波长和网箱框架的边长一致时,波浪单位截面积内的能量损失率达到最大值.     

深海抗风浪网箱养殖设施与装备技术的研究进展

本文根据国家“十五”863计划项目“深海抗风浪网箱的研制”项目实行,结合国际上网箱先进技术的发展,集成现代新材料、渔业工程、海洋化工、机电与自动控制等多项新技术和新工艺,在抗风浪网箱的材料选择、制作与安装工艺、海上锚泊敷设、网衣防污处理、升降控制技术、养殖配套设施以及网箱水动力特性与数值模拟技术方面开展了系统的研究,成功研制出适于开阔海区使用的深海抗风浪网箱养殖设施与装备,发展了离岸工程化生态养殖这一海水养殖新模式。     

海水养殖网箱抗风浪措施的探讨

根据我国30多年以来海水养殖网箱的发展状况．传统网箱和近5年来发展起来的大型深水网箱存在的问题以及2000年以来台风对我国沿海网箱养殖业所造成的损失情况，本文详细论述了网箱养殖安全的重要性以及有关的抗风浪措施，包括网箱框架材料、网衣材料和锚泊系统材料的物理性能以及国产网箱材料与进口材料对比检验的测试结果。讨论了风浪流对网箱安全的影响和网箱安装敷设要考虑的海区海况条件。应用了执行“十五”863项目“深海抗风浪网箱的研制”过程中取得的网箱设计、安装和敷设等方面的发明专利和实用新型专利等自主知识产权。提出了加强网箱抗风浪措施研究和应当开展的深水网箱养殖业可持续发展的科研立项工作。     

渔船避风锚地建设内容探讨

本文从国内渔业防灾减灾所面临的严峻形势开始阐述,对避风锚地影响因素进行了归纳总结,提出了渔船避风锚地的定义和选址要求,分析了渔船的避风作业流程及主要设施需求,从安全辅助设施、监控指挥设施和后勤保障设施三个方面提出渔船避风锚地公益性基础设施的建设内容,对于我国东南沿海受台风影响的省份建设避风锚地具有一定的指导作用和参考价值。     

日本钢结构升降式大型深水网箱结构原理介绍

1日本钢结构升降式深水网箱的结构和作用 日本钢结构升降式大型深水网箱主要是由网箱本体系统和锚泊固定系统二大部分组成。其结构原理如图1。     

网箱的概念简化与力学计算

网箱作为刚性体和柔性体的复合体,工作状态同时处于流场和波浪场的复合作用,直接对网箱进行力学计算目前还存在一定困难.本研究通过对网箱的概念进行简化,通过对网箱概念模型进行力学计算,来定性地探讨网箱的基本性能,以期对网箱的设计提供理论上的参考依据.研究结果表明,水流对网箱的变形有较大影响,而配重对于改善网箱变形的作用是有限度的;作者开发的网箱耐流技术可以很好地改善网箱变形,减少网箱容积损失,当配置为2.0 N流速为1 m/s时,网箱的容积损失率仅为18.4%,其弱点是会使得网箱阻力增加,对网箱锚泊系统的要求提高.研究的结果与目前为止的模型试验结果和在网箱方面的一般经验基本吻合,本研究方法基本上是合理可行的.     

福建省大型抗风浪网箱养殖调查报告

本次调查实地调访了282口网箱,占全省总箱数的65.3%。结果表明,目前福建省抗风浪网箱的养殖种类为真鲷、大黄鱼和美国红鱼,分别占投苗总数的35.9%、24.1%和13.2%,这些种类也是传统网箱养殖的主要种类。抗风浪网箱养殖已呈现出抗台风和环境水质好、病害少、成品鱼品质好、应用海域广阔等优点,养殖真鲷的平均生产水平为9.041 kg/m3,不计设施投资的平均利润率为23.9%,经济效益已初步显现。与传统网箱养殖相比,目前抗风浪网箱养殖苗种个体大、成活率高,但投苗密度低,生产水平仅与传统网箱相当,且存在着空置率高、海域使用不合理等问题,抗风浪网箱养殖的优势还没有得到充分发挥。养殖品种、网箱管理与维护配套设施、饵料和养殖规划等技术问题急需解决。     

实用新型的聚乙烯塑料管网箱养鱼平台制作要点与配套设施

我国海湾现有传统网箱(鱼排)约70万只,网箱平台材料为木质。采用PE管研制出替代传统网箱的平台材料,安装方法快捷与整体移动较方便,并配备太阳能发电系统和生活污物处理设施。PE管网箱养鱼平台主要部件可标准化制作,安装简便,可塑性强。成套设施在珠海经1年多的试验,综合性能优于传统网箱。PE管网箱养鱼平台可为改造和替代传统网箱,养鱼设施技术升级提供借鉴。     

中国水产科学研究院渔业工程研究所

<正>重点研究领域现代渔港工程渔业船舶工程设施渔业工程渔业信息工程渔业防灾减灾工程水产品加工及冷藏工程海洋大型水产养殖工程重大科研成果A 8154型双托艇滑到冷冻渔船设计国内率先使用双托艇滑到坑洞渔船,在海上保鲜加工技术、渔船冷冻工艺等方面填补了多项国内空白,船体总长43.5米,型宽7.6米,型深3.8米,排水量     

Numerical simulation of deformations and forces of a floating fish cage collar in waves

The dynamic behavior of a fish cage collar in waves was investigated using a numerical model based on the finite element method. The floating collar and mooring system were divided into a series of line segments modeled by straight massless model segments with a node at each end. To verify the validity of the numerical model, research data from other authors were cited and compared with the simulated results, the comparison of results showed a good agreement. The numerical model was then applied to a dynamic simulation of a floating cage collar in waves to analyze its elastic deformation and mooring line tension. The simulated results indicated that the greatest deformation of the collar taken place in the position of the mooring line connection point when incident waves were in the same direction. An increase in the length of mooring line would help to decrease the mooring line tension of the collar. Furthermore, the effects of collar dimension, including collar circumference, pipe diameter in cross-section, and pipe thickness, on the dynamic behavior of the floating collar were discussed. The results of this study provided a better understanding of the dynamic behavior of the fish cage collar.     

Numerical investigation of the hydrodynamic behaviors of multiple net cages in waves

Large fish farms that include multiple-cages are becoming common in the aquaculture industry. Selecting an appropriate mooring structure and arrangement of cages is necessary to avoid fish cage and mooring grid system failures. A numerical model based on the lumped mass method and the principle of rigid body kinematics is developed to predict the hydrodynamic response of a fish cage and mooring grid system to regular waves. To validate the numerical model, a series of experiments is conducted. The numerical results of this model correspond with those obtained from experimental observations. Then, two cage arrangements are investigated, and the effect of the wave direction is analyzed. The results show that when the wave incident angle is 0°, the maximum tension forces on the anchor lines of the two cage arrangements are close to each other. There is not a significant difference between the effective fish cage volumes of the two cage arrangements. However, if one anchor line is broken, the two cage arrangements have different degrees of risk of having the cage structures swept away. When the propagation direction of the incident wave changes, the tension forces on the anchor lines also change due to different transfer load paths.     

Design evaluation of a fish cage mooring system with different bridle line connections using model experiments and simulations

Because fish cage systems are strongly influenced by various marine environmental conditions such as currents and waves, structural safety design is of crucial importance during their installation. It is particularly important to design a technical solution for a mooring system. In this study, we designed four types of fish cage systems with different bridle connection arrangements (two single-rope and two multiple-rope connection methods) to evaluate the structural safety of fish cage systems based on the bridle connection arrangement and to propose an efficient design direction. The level of the structural safety of the fish cage system in terms of the resistance force, shape, and inside volume reduction ratio was found to vary according to the position of the frame lines connected to the bridle lines, the number of bridle lines, and the angle between the frame line and the direction of currents and waves. Improved structural safety was observed when the bridle lines were connected to the midpoints of the frame lines compared to those connected to the vertices, and the multiple-rope connection method was found to provide higher structural safety than the single-rope connection method. Increased fish cage system structural safety was also confirmed when the frame line orientation was 90° to the direction of currents and waves compared to that at 45°. From these findings, it can be concluded that the structural safety of a fish cage system can be improved by using multiple bridle lines to disperse the tension of the mooring lines connected to the frame lines and by installing the fish cage with the frame lines aligned at an angle that minimizes the projected area exposed to currents and waves. Moreover, the simulation technique presented in this study is expected to contribute to the efficient evaluation of the structural safety of various fish cage mooring systems designed using multiple-rope connection methods, accounting for the number and position of bridle lines connected on a frame line.     

Water-tank experiment and static numerical analysis of the mooring system of a controllable depth cage

Recent variations in marine environments have increased the risk of aquaculture accidents at sea. This risk can be reduced by installing fish cages at the desired depth, based on environmental conditions such as wave height, the vertical profiles of water temperature, algal concentration, and dissolved oxygen concentration. Most submergible fish cages can be located at only two depths: the sea surface and a submerged depth. In the present study, a fish cage installed at various depths, i.e., a controllable depth cage (CDC), is proposed for avoiding undesirable environments. A water tank experiment is conducted to measure the drag of the cage and the static deformation of the mooring system using a scale model of the actual cage. Then, a simple numerical model based on the balance of forces on each component is developed to analyze the position and the attitude of the cage and the mooring tension of the system. The numerical model is verified by comparing the experimental and numerical results. The outcome showed that the cage and floats moved downstream at an increasing velocity. The results of the numerical simulation supported those of the water tank experiment. However, the simulated vertical positions of a cage and floats were higher compared with experimental results. Additionally, the inclination of angle increased alongside increasing velocity in the numerical simulation, whereas a complex variation was observed in the experiment. This happened because of underestimating the drag on the mooring rope in lower water current velocities; additionally, cage lift was not considered in the numerical model. Despite these discrepancies, the tension of each mooring rope was well predicted because of the dominant tension of the horizontal component. In future studies, the balance of forces on the rope should be predicted more precisely, and variations in cage drag and inclination angle should be included in the numerical model. Additionally, the effect of waves should be considered alongside water currents to ensure the safety of the CDC.     

水流作用下筏式养殖设施动力响应的数值模拟

利用有限单元法建立了水流作用下筏式养殖设施动力响应的数学计算模型,通过数值求解对浮标和吊笼结构的最大位移以及锚绳受力进行分析。计算机模拟结果表明,筏绳在水流作用下产生明显的变形,其形态变化与实际基本相符。当流向一定时,浮标和吊笼的最大位移值以及左右两侧的锚绳受力均随流速的增加而增大。其中,浮标最大位移值7.6m,吊笼最大位移值9.6m。当流速一定时,浮标和吊笼的最大位移值与右侧锚绳受力随着来流角度的增加而增大。左侧锚绳力受来流方向变化影响不明显,其最大值为3 780N。     

HDPE圆形重力式网箱受力变形特性的数值模拟

该研究旨在综合探讨不同网箱周长、浮管管径、网衣高度及网目大小对整体网箱受力变形的影响，为网箱的科学合理选型提供数据参考。设定的网箱周长40—80m，浮管管径250～630mm，网衣高度6～20m，网目大小45～115mm。通过数值模拟方法对4种规格高密度聚乙烯圆形网箱在不同组合条件下网箱锚绳受力、波流力以及容积损失率进行了数值计算。结果表明，大规格网箱的锚绳受力、波流力更大，容积损失率更小，锚绳数量的增加可以大大降低锚绳受力。相比浮管管径，网衣高度和网目大小对网箱受力变形的影响更显著。整体网箱的受力变形随着网衣高度的增加而增大，随网目的增大而减小。     

方形结构网箱单箱体型锚泊系统的优化研究

以方形结构网箱的单箱体型锚泊系统为研究对象,通过力学分析和程序计算得出锚绳张力以及不同来流角度下的阻力系数之和(SRC)两项安全性能指标。结果表明,在理论的最危险受力情况下,单锚绳系统中锚绳张力的最大值为网箱阻力R,在双锚绳系统中则小于R。当双锚绳系统的锚绳安装角度β设置在最佳值22.5°时,SRC获得最小值34.65,该值相比β=1°时的SRC(39.59)下降了约12.5%,相比单锚绳系统的SRC(41.36)则降低了16.2%。     

波浪作用下半潜式养殖网箱水动力特性

半潜式深远海养殖网箱在波浪作用下会发生变形与运动。为保证网箱结构的稳定性,需对其水动力特性进行分析。本研究基于有限元法建立了波浪作用下一种半潜式网箱的数值模型,通过仿真计算求解网箱的锚绳受力与运动情况。首先,将计算机模拟值与物理水槽试验值进行比较,验证数值模型的准确性。然后,分别研究了半潜式网箱在3种压载状态下的动力响应情况,分析比较了不同波浪条件下网箱锚绳张力、垂荡、纵荡和纵摇的计算结果。结果显示,计算值与试验值基本吻合,二者的相对误差在5%左右。当波高一定时,网箱迎浪侧和背浪侧锚绳受力与波浪周期改变无明显关联;当周期一定时,两侧锚绳受力均随波高的增加而增大。网箱的垂荡、纵荡及纵摇值均与波高呈正相关,随着半潜式网箱吃水的增加,网箱的垂荡、纵荡及纵摇值基本呈减小趋势。网箱在3种压载状态下最大垂荡值和纵荡值分别为12.67 m和10.59 m,网箱在空载状态下的最大纵摇值≤15°,表明半潜式网箱结构具有较好的稳定性。研究结果可为我国深远海养殖网箱设计提供理论参考。     

波浪作用下一种鲆鲽类方形网箱水动力特性数值模拟研究

针对鲆鲽类方形重力式网箱在纯波浪条件下的水动力特性,采用数值模拟的方法对鲆鲽类方形深水重力式网箱的主要部件——浮架系统、配重系统、锚碇系统进行了模拟。将模拟结果与实验结果进行分析比较表明,数模与物模各量值吻合良好,平均相对误差均不超过9%,表明数值模拟的方法能较好地模拟鲆鲽类方形深水重力式网箱的水动力特性。在此基础上,用数值模拟的方法,进一步研究了底框质量和网衣高度的改变对网箱各参数的影响,模拟结果显示,底框质量改变主要影响锚绳受力和底框倾角,底框质量从80 g升至100 g再升至140 g的过程中,锚绳受力平均增幅分别为13%和19%,同时增大底框质量有助于减小底框运动倾角,其平均降幅分别为8.8%和9.3%;网衣高度由20 cm增至30 cm后,锚绳受力平均增加15%,同时网衣的增高导致对浮架和底框的牵制作用加大,使得浮架和底框的运动幅度有所减小,降幅不超过10%。在以上研究结果的基础上,为鲆鲽类网箱的设计与优化提供了参考建议。     

潜浮式船型桁架结构深海养殖网箱避浪性能研究

深海网箱作为现代海洋渔业拓展外海养殖空间的重要养殖装备，其布设环境一般较近海更为复杂恶劣，对于保障其安全性和稳定性提出了更高的要求。本研究针对一种单点系泊潜浮式船型桁架网箱开展了模型比尺为1︰40的波浪流水池试验，重点围绕该网箱在不同吃水深度受波浪作用的系泊受力、升沉、纵摇和横摇等水动力学特性进行了比较分析。试验结果显示，波高为7.5~12.5 cm时(原型3~5 m)，网箱漂浮状态即可以满足养殖需求，其系泊力及运动响应均较小，具备较高的安全性和稳定性；恶劣海况时，即本试验中波高为15.0和17.5 cm (原型6 m和7 m)，通过整体下潜的方式网箱具有良好的避浪性能，其中，系泊力减幅达70%以上，升沉、纵摇和横摇等运动分量减幅也达20%~60%；波流试验中，海流对网箱避浪性能存在一定的影响，但总体上仍然具有较好的避浪效果。研究结果可为单点系泊潜浮式深海网箱的安全运行与日常管理提供理论依据和数据参考。