Development Experience of Foreign Green Shipping and Its Enlightenment to China

Based on analysis of green shipping practices of foreign ships manufacturers, ocean carriers ad port countries, their advanced experience was summarized, and its enlightenment to China＇s ＂green shipping＂ was analyzed to realize China＇s dream of becoming ＂ a strong shipping country＂ eady.

Operational Options for Green Ships

Environmental issues and rising fuel prices necessitate better energy-etlicwncy in all sectors, The shipping industry is one of the major stakeholders, responsible for 3% of global CO2 emissions, 14%-15% of global NOx emissions, and 16% of global SOx emissions. In addition, continuously rising fuel prices are also an incentive to focus on new ways for better energy-effectiveness. The green ship concept requires exploring and implementing technology on ships to increase energy-efficiency and reduce emissions. Ship operation is an important topic with large potential to increase cost-and-energy-effectiveness. This paper provided a comprehensive review of basic concepts, principles, and potential of operational options for green ships. The key challenges pertaining to ship crew i.e. academic qualifications prior to induction, in-service training and motivation were discussed. The author also deliberated on remedies to these challenges.

Insight into tribological problems of green ship and corresponding research progresses

The so-called "green ship" is being regarded as a potential solution to the problems that the shipping industry faces, such as energy conservation and environmental protection. Some new features, such as integrated renewable energy application, biomimetic materials, and antifriction and wear resistant coating have been accepted as the typical characteristics of a green ship, but the tribology problems involved in these domains have not been precisely redefined yet. Further, the related research work is generally focused on the technology or material itself, but not on the integration of the applicable object or green ship, marine environment, and tribological systematical analysis from the viewpoint of the energy efficiency design index(EEDI) and ship energy efficiency management plan(SEEMP) improvements. Aiming at the tribology problems of the green ship, this paper reviews the research status of this issue from three specific domains, which are the tribology problems of the renewable energy system, tribological research for hull resistance reduction, and energy efficiency enhancement. Some typical tribological problems in the sail-auxiliary system are discussed, along with the solar photovoltaic system and hull drag reduction in traditional marine mechanical equipment. Correspondingly, four domains that should be further considered for the future development target of the green ship are prospected.

采用Green-Naghdi方程和有限元法计算浅水船波

采用波动方程 /有限元法求解 Green-Naghdi ( G-N)方程计算船舶在有限水深区域的兴波和波浪阻力。把行驶船舶对水面的扰动作为移动压力直接加在 Green-Naghdi方程里 ,以描述运动船体和水面的相互作用 ,并以此来计算水面波动、船底水动压力和波浪阻力。G-N方程比浅水方程增加一个非线性的频散项 ,以补充有限水深对浅水船波的影响。采用随船运动网格的有限元法 ,以 Series 60 CB=0 .6船作为算例给出浅水船波的计算结果 ,并与浅水方程的结果进行了比较。计算结果表明 ,当船速小于临界速度时 ,由于频散的影响 ,G-N方程给出的船后尾波波高比浅水方程的结果大 ,同时波浪阻力也比浅水方程的结果有所提高。当船速大于临界速度时 ,G-N方程的计算结果与浅水方程基本相同 。

Future Outlook of Artificial Cavity Application for Reducing Hydrodynamic Resistance of Containerships

Absolute commitment to reduce the impact of greenhouse gas emissions while increasing fuel efficiency and power density requires further enhancement of prime mover characteristics and special coatings, but mostly requires compliance with EEDI （energy efficiency design index） measures. For the container shipping industry this represents significant increases in fuel costs that can be mitigated above all by reduction of power demand, that is, of ship frictional resistance. In this respect, this paper discusses advantages attainable by application of the ACS （air cavity system） technology on the basis of recent KSRC （Krylov State Research Centre） studies Savings in operating costs yielded by the enhanced propulsion performance for ships fitted with this system are illustrated by a case study of a containership.

Mathematic Model of Green Function with Two-Dimensional Free Water Surface

Adopting complex number theory, a mathematic model of Green function is built for two dimension free water surface, and an analytic expression of Green function is obtained by introducing two parameters. The intrinsic properties of Green function are discussed on vertical line and horizontal line. At last, the derivation expression of Green function is obtained from the formula of Green function.

Domain Decomposition and Matching for Time-Domain Analysis of Motions of Ships Advancing in Head Sea

A domain decomposition and matching method in the time-domain is outlined for simulating the motions of ships advancing in waves. The flow field is decomposed into inner and outer domains by an imaginary control surface, and the Rankine source method is applied to the inner domain while the transient Green function method is used in the outer domain. Two initial boundary value problems are matched on the control surface. The corresponding numerical codes are developed, and the added masses, wave exciting forces and ship motions advancing in head sea for Series 60 ship and S175 containership, are presented and verified. A good agreement has been obtained when the numerical results are compared with the experimental data and other references. It shows that the present method is more efficient because of the panel discretization only in the inner domain during the numerical calculation, and good numerical stability is proved to avoid divergence problem regarding ships with flare.

我国航运业绿色低碳发展的需求、路径与展望

为探讨航运业在综合运输体系中的重要性,并针对加速航运业绿色低碳发展对实现交通运输行业双碳战略目标的意义展开分析。通过考察航运业当前的碳排放状况,分析我国在绿色低碳发展方面存在的问题,对国内外绿色航运政策需求及其对航运业的影响进行综合评估。在此基础上,研究我国航运业绿色低碳发展的路径,包括总体思路、基本原则,以及相应的策略与实施措施,展望航运业绿色低碳发展的技术创新方向,提出从能源替代和运营管理两个方面促进航运业绿色低碳发展。

Sloshing-Coupled Ship Motion Algorithm for Estimation of Slosh-Induced Pressures

The effect of coupling between sloshing and ship motions in the evaluation of slosh-induced interior pressures is studied. The coupling between sloshing loads and ship motions is modelled through a hybrid algorithm which combines a potential flow solution based on transient Green function for the external ship hydrodynamics with a viscous flow solution based on a multiphase interface capturing volume of fluid(VOF) technique for the interior sloshing motion. The coupled algorithm accounts for full nonlinear slosh forces while the external forces on the hull are determined through a blended scheme of linear radiationdiffraction with nonlinear Froude-Krylov and restoring forces. Consideration of this level of nonlinearities in ship motions is found to have non-negligible effects on the slosh-coupled responses and slosh-induced loads. A scheme is devised to evaluate the statistical measure of the pressures through long-duration simulation studies in extreme irregular waves. It is found that coupling significantly influences the tank interior pressures, and the differences in the pressures between coupled and uncoupled cases can be as much as 100% or more. To determine the RAO over the frequency range needed for the simulation studies in irregular waves, two alternative schemes are proposed, both of which require far less computational time compared to the conventional method of finding RAO at each frequency, and the merits of these are discussed.

Time Domain Rankine-Green Panel Method for Offshore Structures

To solve the numerical divergence problem of the direct time domain Green function method for the motion simulation of floating bodies with large flare, a time domain hybrid Rankine-Green boundary element method is proposed. In this numerical method, the fluid domain is decomposed by an imaginary control surface, at which the continuous condition should be satisfied. Then the Rankine Green function is adopted in the inner domain. The transient free surface Green function is applied in the outer domain, which is used to find the relationship between the velocity potential and its normal derivative for the inner domain. Besides, the velocity potential at the mean free surface between body surface and control surface is directly solved by the integration scheme. The wave exciting force is computed through the convolution integration with wave elevation, by introducing the impulse response function. Additionally, the nonlinear Froude-Krylov force and hydrostatic force, which is computed under the instantaneous incident wave free surface, are taken into account by the direct pressure integration scheme. The corresponding numerical computer code is developed and first used to compute the hydrodynamic coefficients of the hemisphere, as well as the time history of a ship with large flare; good agreement is obtained with the analytical solutions as well as the available numerical results. Then the hydrodynamic properties of a FPSO are studied. The hydrodynamic coefficients agree well with the results computed by the frequency method; the influence of the time interval and the truncated time is investigated in detail.

船舶有航速时三维时域格林函数计算方法研究

船舶工业CAE软件势流求解器的开发对势流计算方法的可靠性提出要求,本文针对船舶有航速时深水三维时域格林函数计算方法开展研究。首先引入三维时域自由面格林函数,其瞬时项的求解采用Hess&Smith方法,自由面记忆项的求解采用美国密歇根大学Beck团队的方法。其次,分区域推导出三维时域自由面格林函数记忆项及其导数的编程所用的数学展开表达式。然后,采用间接法模型求解分布源强和速度势,并采用压力直接积分法求出时域辐射力。最后,针对Wigley I船型开展了辐射力计算,并与公开的试验及计算结果进行对比,验证本文方法的可靠性。

数字化视阈下航运业企业发展方式绿色化转型

党的二十大报告对数字强国和发展方式绿色化转型提出明确要求。航运业企业属于高能耗行业,也是实施数字化的重点部门,基于A股航运业上市公司面板数据,在测度航运业企业数字化程度和绿色化水平的基础上,分析数字化对航运业企业绿色化转型的影响及异质性效应,引入绿色创新和产业结构升级作为中介变量考察影响的传导机制。实证研究发现:数字化能够显著促进航运业企业绿色化发展,数字化对不同地区的航运业企业绿色化发展有不同影响。进一步的机制检验表明,数字化通过促进绿色创新、推动产业结构升级而影响航运业企业绿色化发展。最后从鼓励航运业企业大力推行数字化、引导数字化和绿色化融合发展、根据企业地区特点采取不同策略等方面提出政策建议。

燃料电池船舶混合动力系统能量管理研究综述

在“双碳”目标下,发展燃料电池船舶是实现航运业转型升级和低碳化的重要发展方向之一。面对当前燃料电池上船的诸多问题,混合动力系统成为燃料电池船舶应用的有效解决方案,其能量管理的研究也成为核心研究方向之一。系统梳理燃料电池船舶的发展概况,针对燃料电池船舶多类型能源能量管理中涉及的能量调度问题以及变换器功率分配问题进行综述;分析各类方法的优缺点及其在实船上应用的可能性;探讨燃料电池船舶推广可行性和发展方向,以期能为技术创新和工程应用提供参考。

船舶碳减排国外政策制度管理经验研究

本文研究分析了欧盟、美国、挪威和日本在船舶碳减排方面的政策框架、技术创新、绿色能源应用、国际合作和环保港口建设等方面的举措。研究发现,国外国家在法规要求、技术创新和国际合作方面都取得了显著进展,电动船舶技术、氢燃料电池技术等清洁能源的应用也逐渐成为趋势。然而,各国仍面临技术成本、能源基础设施建设、国际标准协调等共同挑战。最后,研究提出了中国在船舶碳减排领域的启示和建议,强调了政策完善、技术创新、国际合作和港口环保设施建设的重要性,以推动中国航运业的绿色、低碳、可持续发展。

船舶轮缘推进器关键技术研究现状和发展趋势

采用电力直驱模式来完成电能与机械能的无传动转化是高端交通动力装备领域的未来战略性技术之一。轮缘推进器(RDT)作为一种高度集成的电力直驱推进,是近年来研究的热点。文章梳理了船舶轮缘推进器的6项关键技术,包括水力部件设计及优化、电机设计及控制、水润滑轴承的设计和性能强化、系统集成与测试、船体匹配及联合控制以及可靠性评估与智能运维;阐述了各项技术的研究现状和趋势,总结了国内外RDT产品和实船应用情况。研究和应用表明,节能、环保、灵活的轮缘推进器是绿色智能船舶电力推进形式的重要选择,高性能轮缘推进器专用化设计、效能提升和状态监测以及智能运维是轮缘推进器未来重要发展趋势。

新一代航运系统的未来船舶技术展望

未来船舶技术对于新一代航运系统至关重要。为推动国际海事组织IMO所提出的航运智能化与绿色化进程,展望未来船舶技术发展方向。探讨未来船舶跨域协同架构关键技术,提出未来船舶发展的首要任务。明确以“船-岸-云”技术架构及“岸基驾控为主、船端值守为辅”运行模式为核心的未来船舶发展目标。强调我国应加快相关领域关键技术攻关,构建船舶岸基驾控系统,促进多领域合作,持续向造船强国和航运强国的发展目标迈进。

三维时域自由面格林函数法的时域绕射力计算研究

船舶工业CAE软件势流求解器的开发对势流计算方法的可靠性提出要求,本文针对三维时域面元法开展绕射力计算研究。首先引入三维时域自由面格林函数,其瞬时项的求解采用Hess&Smith方法,记忆项的求解采用Beck团队的方法;其次,推导出全浪向绕射力脉冲函数法编程所用的数学表达式;然后,采用分布源模型求解源强和速度势,并采用压力直接积分法求出时域绕射力;最后,针对Wigley I船型开展绕射力和FK力计算,并与公开的试验和计算结果进行对比,验证本文方法的可靠性。本文方法和代码可用于船舶工业CAE软件势流求解器和波浪中船舶非线性失稳运动预报。

内河船舶绿色化评估体系及评估方法研究

为进一步完善内河船舶绿色化评估指标体系,提升内河船舶绿色化评估系统的科学性、准确性、可靠性、灵活性及效率,在全面、系统地分析绿色船舶内涵的基础上,结合绿色船舶技术的发展现状,归纳总结了绿色技术应用对整个船舶生命周期产生的影响。从船舶本体、应用效果、经济性三个维度构建了内河船舶绿色化评价指标体系,综合分析并确定了各项指标的评估方法,进而构建了各项指标的评估模型。以一艘内河混合动力散货船为研究对象,将实船测试数据带入搭建的评估模型开展实船绿色化评估验证,分析目标船舶的绿色化水平,相较于柴油动力系统,绿色技术应用可使目标船在营运年限内碳排放总量减少12.3%,成本减少8.9%,EEDI计算值(Attained EEDI)相比EEDI-Ⅲ阶段基准值下降约23.5%。

船舶岸电政策下港航企业低碳行为演化研究

为探究港航企业在船舶岸电政策下推进岸电应用的低碳行为演化路径,构建政府、港口企业、航运公司三方参与的演化博弈模型,判断在有限理性条件下各主体决策选择行为的稳定性状态,并通过MATLAB数值仿真分析政策变化对系统演化路径的影响。研究表明:系统存在3个稳定均衡点,分别对应船舶岸电发展过程中的三个阶段,初期、中期、成熟期;政府在推进船舶岸电发展中起主导作用,其积极制定并落实相关政策可促进港航企业选择使用岸电。针对货运码头岸电使用率较低的现状,补贴力度比监管力度作用更强,后期政府应加大对岸电使用的系列补贴。

2023年世界船海市场评述与2024年展望

2023年世界经济增速由2022年的3.5%放缓至3.1%,但表现出明显的韧性,全球不同经济体的经济增长分化加大。随着全球疫情管控的放开和地缘冲突的增加,大宗商品贸易受到扰动,2023年海运贸易仍预计增长2.4%。船舶行业的市场基本面稳定向好,市场主要指标保持增长,以载重吨计,新船订单量同比增长25%,完工交付量增长12%。其中油船新船订单同比增长356.6%,散货船新船订单同比增长33%,集装箱船和气体船则有所回落。中国新船订单量在主要造船国中保持领先,占全球市场份额68%。采用绿色替代燃料的双燃料船舶订单持续增长,占全球订单的34%。预计2024年船舶行业或将维持上行趋势,尤其是散货船和油船。脱碳进程的加快和人工智能技术的发展也将为船舶航运业的高质量发展带来机遇和挑战。