风帆助航船操纵性研究

文中首先建立了风帆助航船的数学模型,计算和分析了帆对船在风中的风速限界线和可自由操纵区的影响,利用最优控制理论推导出使船在风中回转战术直径为最小的操帆规律的近似公式。然后对风帆助航船在风中的回转性能进行了数值计算,研究了帆的位置对船舶操纵性的影响。结果表明,风帆助航船若帆的位置布置得当,且适当地操帆,则其在风中的船舶操纵性能比未装帆时要好得多。     

CFD数值模拟船舶在波浪中的回转操纵运动

[目的]船舶回转操纵运动能够反映出船舶的回转特性,与船舶的航行安全密切相关。[方法]为此,采用基于重叠网格技术的CFD求解器naoe-FOAM-SJTU,对标准船模ONRT在波浪中自由回转操纵运动进行直接数值模拟。运用动态重叠网格技术求解船、桨、舵系统复杂运动,计算中,螺旋桨转速对应于静水中的船模自航点进行35°转舵,实现自由回转船舶操纵运动。通过全粘性流场的整体求解,给出波浪中自由回转操纵运动中船舶六自由度运动、螺旋桨和舵的水动力载荷变化,以及波浪中船舶的回转圈特征参数,并与同试验结果进行对比。通过数值计算得到精细的流场信息,分析波浪对船舶自由回转操纵运动的影响。[结果]数值预报得到的船舶运动轨迹、回转圈参数与试验值吻合较好,证明naoe-FOAM-SJTU求解器对于波浪中船—桨—舵相互作用下的船舶自由回转操纵运动数值预报的适用性和可靠性。[结论]船舶回转操纵运动的数值模拟,可为回转性能的评估提供有效的前期评估手段。     

主动舵潜水三相异步电动机

主动舵是船舶动力定位和低速航行的重要设备,其电机及螺旋桨安装在船体舵叶的腹板中,见图1。采用主动舵可显著改善船舶操纵性能,减小船舶回转直径。万吨级船舶可用主动舵作3节左右的低速航行;也可用来抵消风     

基于LQR限宽水域中KVLCC2操纵运动控制研究

在航道宽度受限制的水域中,船舶会受到岸壁效应的影响,横向力与首摇力矩将发生变化,这会对船舶的航行安全产生不利的影响。鉴于此问题,本文应用现代控制理论最优控制LQR方法,对在限制水域中航行的超大型油轮KVLCC2的操纵运动进行控制研究。为便于LQR控制器的设计,采用线性状态空间形式的操纵运动方程,基于数值模拟获取的相应线性水动力系数,计算出使目标函数值最小的增益矩阵K,从而得到满足最优控制规律的时域舵角变化,实现对不同宽度水域中船舶运动的最优控制,并与极点配置控制法作比较,验证LQR控制器的优越性。结果表明,当船岸距离d/L≥1.2时,船舶基本不受岸壁效应的影响,控制幅度极小;当岸壁距离d/L=0.25时,摆舵角度将超过6°,同时船舶前进速度也将下降,下降幅度将超过前进速度的10%,岸壁效应明显。     

基于LQR限宽水域中KVLCC2操纵运动控制研究

在航道宽度受限制的水域中,船舶会受到岸壁效应的影响,横向力与首摇力矩将发生变化,这会对船舶的航行安全产生不利的影响.鉴于此问题,本文应用现代控制理论最优控制LQR方法,对在限制水域中航行的超大型油轮KVLCC2的操纵运动进行控制研究.为便于LQR控制器的设计,采用线性状态空间形式的操纵运动方程,基于数值模拟获取的相应线性水动力系数,计算出使目标函数值最小的增益矩阵K,从而得到满足最优控制规律的时域舵角变化,实现对不同宽度水域中船舶运动的最优控制,并与极点配置控制法作比较,验证LQR控制器的优越性.结果表明,当船岸距离d/L≥1.2时,船舶基本不受岸壁效应的影响,控制幅度极小;当岸壁距离d/L=0.25时,摆舵角度将超过6°,同时船舶前进速度也将下降,下降幅度将超过前进速度的10%,岸壁效应明显.     

大型船舶自动舵系统精准智能航向控制研究

为保持船舶在指定轨迹上航行,目前使用最为广泛的技术是船舶航向自动舵控制系统。基于航行安全和节约成本的考虑,船舶航行对自动舵的精确度提出了越来越高的要求。目前,通常采用船舶操纵运动模型研究船舶自动舵控制系统。通过分析船舶运动及其受到干扰力作用的情况,建立船舶控制系统数学模型。本文结合PID控制、模糊控制和粒子群算法,分析研究船舶航向自动舵控制系统。     

基于等效动稳定性系数的潜艇运动控制方法

对由线性运动方程和Routh-Hurwitz判别法导得的操舵比例函数求解,获得潜艇运动控制新方法,将控制增稳所需的修正舵角与原舵角组合成新指令舵角,可改善潜艇的航行品质。以具有十字舵的某型潜艇为对象求解6自由度运动方程,其中典型的潜艇水下定深回转工况仿真模拟表明：操舵比例系数与水动力导数和等效动稳定系数有关,控制增稳效果受到运动特征量和潜艇操舵角度等因素的影响。潜艇运动控制新方法改善了潜艇航行过程中的运动响应,提高了那些由于自动稳定性不足而难以操控的潜艇的控制稳定性。潜艇运动控制新方法为未来潜艇通过减小操纵面来优化自身综合水动力性能提供了新的技术途径。     

基于海上航线风能资源特征的船舶风帆选型

将风帆装置的气动特性、船舶航线信息和典型航区风能资源特征相结合，提出一个船舶风帆选型方法。根据风洞试验数据分别计算并归一化圆弧形翼帆、滚筒帆、涡轮帆和天帆的风力助推系数和横漂系数；考虑不同航线上风力、风向的概率数据计算出不同风帆的助推指数和横漂指数，将每年12个月的助推指数和横漂指数相加得到总助推指数和总横漂指数；以不同风帆的总助推指数较大，兼顾较小总横漂指数的优选原则，确定最佳的风帆类型。以上海—香港航线和横滨—洛杉矶西段航线为例，利用这种风帆选型方法，计算出2个航线不同风帆助航装置的综合助推指数、横漂指数和总评价指数，确定了2条航线的最佳风帆装置，为船舶风帆的选型设计提供依据。     

船舶在风浪中航行时保向问题的探讨

本文在建立船舶在风浪中的低频操纵运动方程式的基础上，探讨了船舶在风浪中的舵力保向问题。从工程实用的角度，提出了一个船舶在风浪中航行时保向舵角的近似计算公式。以“育英轮”为例，进行了计算。从保向的角度，提出了船舶在大风浪中航行时，提高抗风浪能力方法和安全航行的措施，并可望对实际工作有一点指导意义。     

计算简易操船模拟系统

计算简易操船模拟系统由 I B M 微机及其外部设备,机、舵模拟操作台,船舶操纵运动方程,风、流边界等环境的软件组成。通过该系统实施考虑风、流边界等条件下船舶进出港操船模拟,提供操船方法,培训船舶驾驶员。该系统根据需要也可提供船舶各种标准机动的航行结果。系统采用人(?)机对     

风帆助航渔船的稳性及经济性分析

风帆助航是船舶节能减排的重要途径。本文以1条鱿鱼钓船作为研究对象,根据该船的特点选择NACA0006型帆和圆弧型帆作为辅助风帆,然后利用Fluent软件建立所选风帆模型,对这2种风帆的空气动力性能进行数值模拟计算。根据软件的计算结果估算风帆助航时鱿鱼钓船的每年节油量以及所减少的二氧化碳排放量。通过对风帆助航鱿鱼钓船的稳性进行计算分析,可以确定只要合理地安装和操作风帆,风帆助航渔船是能满足稳性要求的。     

基于CFD的风帆助航技术效能分析

在模型试验的基础上,运用计算流体力学(CFD)方法,分析了基于机翼理论的风翼帆船利用风能辅助推进的特性.在仿真软件Fluent的仿真计算的基础上,当采用风帆助航技术时,对风帆产生的推力及由此引起船舶阻力变化进行了分析,从而对风帆助航技术的效能进行评估与分析,得出了远洋船舶利用清洁能源(风能)在经济性与环保性方面的可行性.并提出风帆助航技术应用于大型远洋船舶后续需要解决的问题.     

Steady sailing performance of a hybrid-sail assisted bulk carrier

The steady sailing performance of a sail-assisted bulk carrier is investigated utilising towing-tank derived hydrodynamic derivatives and wind tunnel measured aerodynamic properties of the sails and the ship. The aerodynamic characteristics investigated include the ship hull at the fully-loaded draught, the sail–sail interaction effects for two sets of four identical hybrid-sails, and the sail–hull interaction effects for the same two sets of identical sails in the presence of the selected bulk carrier hull-form. This is in addition to lift–drag measurements of single isolated sails of each shape. The form of the two sets of soft sails was rectangular and triangular. This paper is concerned with assessing the benefits of a sail-assisted ship operation, and hence a steady-state rather than complete time-domain integrations of the governing equations are reported. The results of the completed analysis suggest that the benefits of the derived sail generated driving force are greater than the overhead of equipping the ship with a selected system of hybrid-sails. Sail-assisted ships could represent an important contribution to an improving global environment by reducing the demands for a driving force through the propeller.     

基于自航流场数值模拟的舵球节能流场分析

本文采用快速性数值模拟方法对加装舵球的36000吨散货船进行了节能评估。结果显示,加装舵球能起到一定的节能效果。之后本文对有、无舵球的两种方案的自航数值模拟流场进行了对比,分析获得了舵球节能的原理。本文模拟结果不仅可作为模型试验的有力补充,也可为舵球的优化设计提供重要参考。     

4000DWT多用途船襟翼舵的设计与安装

襟翼舵作为一种特殊舵,与普通舵相比,在提高舵效,改善船舶操纵性能等方面有着明显的效果,作为一种用在江海直达多用途船上的襟翼舵,其设计与安装显得尤为重要.通过以舵参数为设计基础,合理结构设计以提高舵效,细化其安装工艺、提高建造质量,从性能、结构、工艺上介绍了4000DWT多用途船襟翼舵的设计与安装情况,最后通过对该型船的试航情况分析证明其襟翼舵是成功的.     

Study on the maneuverability of a large vessel installed with a mariner type Super VecTwin rudder

The suitability of the Mariner type Super VecTwin rudder (hereinafter, the MSV rudder) for a large vessel is assessed in this article. Several experiments in a maneuvering pond were carried out and their results analyzed and summarized. Free-running tests such as turning, zigzag, and stopping tests were carried out with a 4-m free-running model of a very large crude carrier (VLCC) ship with the MSV rudder and the Mariner rudder. The results were compared to validate the maneuverability of a VLCC-sized a ship installed with the MSV rudder. A mathematical model of an MSV rudder is proposed for maneuvering simulation of a large vessel. To develop a maneuvering simulation for the model ship that was used in the free-running tests, hydrodynamic coefficients were estimated based on Kijima's regression formula. The coefficients of interaction between the hull and rudder (t_R, a_H, x_H) were obtained from a self-propulsion test in a towing tank. The complicated flow around the rudders is simplified to model the flow speed around the rudders. This simplified flow speed is utilized to compare the time histories of the free-running tests with the simulations. The mathematical model of the MSV rudder was further improved using the results of this comparison.     

潜艇围壳舵和首舵水动力性能比较

安装在潜艇上的首部水平舵位置对于潜艇在垂直方向的稳定性以及操纵性具有重大意义.本文首先通过Fluent 14.0计算Suboff模型的阻力以及DTMB舵型的升、阻力,仿真结果与实验结果吻合较好.然后计算带围壳舵Suboff潜艇和带首舵Suboff潜艇的阻力、升力特性,并比较了潜艇带首舵和围壳舵的升阻力特性差异,以及对艇体表面压力分布和尾部流场的影响.计算结果显示,相同舵角下,围壳舵和首舵阻力相差不大,围壳舵升力比首舵升力大.相同舵角下,潜艇总阻力相差不大,带首舵潜艇总升力、总力矩比带围壳舵潜艇总升力、总力矩大.围壳舵舵角的变化对艇体表面的压力变化影响相对首舵来说较小.围壳舵和首舵在较大舵角下,都会对尾水平舵产生显著影响.     

Sail–sail and sail–hull interaction effects of hybrid-sail assisted bulk carrier

In a previously reported study, wind tunnel experiments were undertaken to investigate the aerodynamic characteristics of hybrid-sails in isolation. Such sails are seen as providing a worthwhile reduction in the delivered power to the propeller and hence the engine generated thrust, with a corresponding reduction in the CO₂ production of diesel engine exhaust. In this paper, wind tunnel testing is used to investigate sail–sail interaction effects for two sets of four identical hybrid-sails, and the sail–hull interaction effects for the same two sets of four identical sails in the presence of a bulk carrier hullform. The analysis presented suggests that to build a sail-assisted ship requires an appreciation of the sail–sail and sail–hull interaction effects.     

Mathematical model of single-propeller twin-rudder ship

A mathematical model of a single-propeller twin-rudder ship has been developed from captive and free running model experiments. An open water rudder experiment was carried out to figure out the characteristics of the rudder. Captive experiments in a towing tank were carried out to figure out the performance of a single-propeller twin-rudder system on a large vessel. Interactions between the hull, propeller and twin rudders, including mutual interactions between the twin rudders, were expressed with several coefficients that were calculated from the experimental results at various ship speeds. In the analysis, the unique characteristics of a single-propeller twin-rudder ship, which affects rudder forces, were explained and formulated in the mathematical model. The captive model tests were conducted with zero ship’s yaw rate, so the interaction coefficients, which are influenced by the yaw rate, are determined from free running model experiments. Validation of the mathematical model of a single-propeller twin-rudder system for a blunt body ship is carried out with an independent set of free running experiments, which were not used for determining the interaction coefficients. The validated numerical model is used for carrying out simulations. Based on simulation results, some recommendations have been proposed for installing a single-propeller twin-rudder system.