红土镍矿运输船倾覆的机理研究

红土镍矿是一种非常特殊的矿物质,在运输过程中,如果船舶遭遇风浪,或船舶本身长时间的振动,都会导致该矿石的表面液化。液化后的混合液体具有较强粘性,可以形成自由液面。为分析、解释运输该种货物船舶发生倾覆沉没的原因,此文采用数学建模的方法,对运输红土镍矿的船舶进行了模拟计算。得出的初步结论是粘性流体在舱内的运动与船舶的摇摆运动存在一个相位滞后关系,当船舶的横摇周期有利于相位滞后一个适当的位置时,粘性流体就无法返回到原来的位置,而是在船舶一侧继续堆积,形成越来越大的外力矩,使船舶最终倾覆沉没。     

散运红土镍矿风险管控

本文阐述了影响散装货船载运红土镍矿安全的主要因素,分析了舱内红土镍矿液化、位移的过程,以及对船舶安全所带来的影响,并据此提出了散装货船载运红土镍矿时管控安全风险的措施。一、影响散装货船载运红土镍矿安全性的主要因素到目前为止,虽然航运界已对散装货船载运红土镍矿的安全性引起了高度重视,但仍未最终确定促使这些船舶沉没的真正原因。当前,被航运界公认的观点是红土镍矿同其它精粉铁矿一样,     

某散货船载运镍矿稳性分析

针对镍矿在运输过程中易液化,造成船舶发生危险甚至倾覆的问题。文章阐述了镍矿特性及易流态化货物完全液化后自由液面和货物移动对船舶稳性的影响,并通过实船数据计算出货物移动后稳性的变化。货物在液化后会形成横倾力矩,使稳性减小,甚至丧失。     

红土镍矿安全运输经验

文中分析了红土镍矿运输存在的巨大风险,并根据多年运输红土镍矿的成功经验,介绍了公司和船舶化解红土镍矿运输风险应采取的针对性安全措施,对船舶安全运输红土镍矿具有重要意义。     

远洋镍矿运输安全分析

为提高镍矿运输的安全性,避免运载镍矿船舶发生沉没事件,对船载镍矿的安全运输技术进行分析。总结实际操作中测定镍矿含水量的方法,判断装运镍矿的自由液面对船舶稳性的影响,提出在监控镍矿装运过程中的注意事项及操作要点,并对镍矿运输船舶的安全运营提出合理建议。     

货舱内液化矿砂晃荡机理及数值计算研究

装载含水量较高矿砂的船舶在长时间摇摆和振动时,装载的矿砂会出现液化现象,其中的水分会析出,并在矿砂表面形成自由液面.受液化矿砂的粘性流动及表层液面的影响,运输该类货物的船舶易发生倾覆事故.建立了载有液化矿砂的三维货舱数值模型,探讨了货舱晃荡时矿砂液面、壁面载荷以及货舱横摇力矩的变化规律等;结合横摇实验现象对液化矿砂晃动机理和危害性进行了初步验证.结果表明：货舱内粘性矿砂的流动滞后于货舱的横摇运动,因而货舱横摇力矩的变化与货舱运动存在着相位滞后的关系,其最大值发生在货舱处于最大晃动角度后返回到平衡位置的过程中;货舱回摇过程中,倾侧的液化矿砂不能及时回流,会在一侧产生堆积,进而增加船舶倾侧力矩,最终可能会导致船舶倾覆.     

"镍矿"海运之灾何时消

去年年底,中国航海界经受了近年来少有的安全危机。10月28日,浙江收货人光租一艘"建富星"轮(1970年造)装有4700吨红土镍矿,这艘巴拿马级散货船在琉球群岛南沉没。11月9日,某散货船(1970年造)装有红土镍矿在台湾东部海面沉没。11月10日,N远洋公司M轮从印尼运红土镍矿回张家港卸货,途经冲绳岛南340海里处,倾覆沉没,25名船员,     

散运红土镍矿 风险管控

本文阐述了影响散装货船载运红土镍矿安全的主要因素，分析了舱内红土镍矿液化、位移的过程，以及对船舶安全所带来的影响，并据此提出了散装货船载运红土镍矿时管控安全风险的措施。     

带自由面船体周围粘性流场数值模拟

利用FLUENT流体软件,通过求解三维粘性不可压RANS方程和使用标准k-ε湍流模型对带自由液面船体进行了周围粘性流场的数值模拟。自由液面采用VOF方法处理,得出了不同弗劳德数下船体的粘性阻力系数,并与ITTC1957给出的平板摩擦阻力系数计算公式以及巴普米尔粘压阻力系数公式两者所求的粘性阻力系数相比较,验证了本文方法的可行性,为船舶阻力预报提供了更为精确的流体分析方案。同时,利用VOF方法可以很好的捕捉自由液面波形,反应了船体的兴波现象,为船体优化设计提供重要的参考。     

船载固体散货流态化数值分析

散货船装载的镍矿、铁矿在运输过程中会发生流态化,流态化导致货物流动性增强,从而降低船舶稳性。当船舶在波浪中航行时,货物的移动会产生一个额外的力矩,该力矩有可能导致船舶倾覆。基于离散元方法,对不同含水率的货物进行了静倾斜、休止角的数值模拟,在全尺度计算中给定了颗粒尺寸和时间步长的选取标准,并采用全尺度货舱模型分析了影响货物稳定性的关键参数。该数值分析方法可为固体散货海上运输过程中船舶稳性预测和安全隐患评估提供参考。     

A numerical study of the effects of the longitudinal baffle on nickel ore slurry sloshing in a prismatic cargo hold

The nickel ore slurry sloshing in a rolling partially loaded prismatic cargo hold with a longitudinal baffle is investigated. A numerical model based on the volume of fluid (VOF) method and the non-Newtonian Herschel-Bulkley and Bingham equations is proposed to study the dynamic behavior of nickel ore slurry sloshing. The numerical model is solved by using the finite volume approximations and the dynamic mesh technique is utilized to handle the cargo hold's motion. After taking grid and time step independence study, the numerical results are compared with experimental data. Comparisons show good agreement in the cases investigated. Further, the relationship between the moment amplitude induced on the hold boundary and the excitation frequency is checked numerically. The ratio of baffle height to the initial cargo depth has been changed in the range of 0.0 ≤ h_B/d ≤ 1.2. The variation of the sloshing-induced moment and the deformation of the free surface under different baffle heights have been obtained and discussed. To clearly understand the sloshing behavior of nickel ore slurry, the sloshing of liquid water has also been carried out. Meanwhile, the dynamic viscosity of the nickel ore slurry is monitored. The critical baffle height with regard to the sloshing-induced moment and the elevation difference of the free surface at two sides of the cargo hold has also been presented and discussed.     

论海运承运人行使留置权的范围

“承运人对船载货物的留置权是一种特殊的留置权。本文通过对国内立法趋势的研究以及国外相关法律的比较,得出了承运人对船载货物行使留置权不应以货物所有权归属债务人为条件的结论,并详尽阐述了相关理由。     

Optimizing the transportation of international container cargoes in Korea

This paper considers a multimodal transportation problem, which is the problem of determining the transportation flow, i.e. volume of container cargoes, and the transportation mode in each trade route, for the objective of minimizing the sum of shipping and inland transportation costs. The problem takes account of two restrictions: maximum cargo volumes capacitated at each seaport and maximum number of vehicles available at each transportation mode. To solve optimally the problem, this paper employs a mixed integer programming, which is an operations research technique. A case study is performed on the container cargo data in Korea and we draw several implications to improve efficiency in the transportation of international trade cargoes in Korea.     

Optimizing the transportation of international container cargoes in Korea

This paper considers a multimodal transportation problem, which is the problem of determining the transportation flow, i.e. volume of container cargoes, and the transportation mode in each trade route, for the objective of minimizing the sum of shipping and inland transportation costs. The problem takes account of two restrictions: maximum cargo volumes capacitated at each seaport and maximum number of vehicles available at each transportation mode. To solve optimally the problem, this paper employs a mixed integer programming, which is an operations research technique. A case study is performed on the container cargo data in Korea and we draw several implications to improve efficiency in the transportation of international trade cargoes in Korea.     

基于CFD的船舶破舱进水时域模拟

船舶因破损进水导致危险情况甚至倾覆是船舶安全性研究中的重要问题.船舶在破损后进水的过程中,可能存在比最终状态更加危险的中间状态.本文以STAR-CCM+软件为研究工具,实现了对某客滚船瞬时非对称进水的动态模拟.针对自由漂浮的客滚船破损情景,论文利用VOF方法模拟水气自由液面,并首次利用重叠网格(Overset Grid)动网技术结合DFBI(Dynamic Fluid Body Interaction)六自由度求解器处理船舶破舱进水过程中的船舶升沉、横摇等运动.模拟结果可以得到舱内液面和船舶浮态随进水时间的变化情况,观察到水柱射流、水花飞溅等瞬时现象;将最终浮态结果与传统准静态方法相比较,吻合较好.     

Importance of several nonlinear factors on broaching prediction

In order to realize a more quantitative prediction of broaching and capsizing in following and quartering seas, existing mathematical modelling techniques should be upgraded. Therefore, it is necessary to systematically examine all factors relevant to capsizing in following and quartering seas. To this end, we first attempted to examine the prediction accuracy of wave-induced forces by comparing calculations with captive model experiments. As a result, we found that a wave-induced surge force has a certain nonlinearitiy with respect to wave steepness. The nonlinearity of sway–roll coupling with respect to sway velocity was also found, and our numerical result with these nonlinearities improves the prediction accuracy of the critical ship speed of capsizing in following and quartering seas. The importance of the wave effect on propeller thrust was also examined. We found that this effect is not negligibly small and could improve capsizing predictions in heavy following and quartering seas. Finally, we attempted to investigate the importance of nonlinear heel-induced hydrodynamic forces on numerical predictions of capsizing due to broaching. Here, we propose a new procedure for captive model experiments to obtain hydrodynamic forces with various heel angles up to 90°, and data on heel-induced hydrodynamic forces with respect to heel angle in calm water are provided. We then compare the numerical simulations with the nonlinear heel-induced hydrodynamic forces and without them. These time series comparisons show that the effect of nonlinear heel-induced hydrodynamic forces in calm water is not negligibly small for the case of ship capsizing due to broaching.     

秘鲁某矿石码头系缆分析

本项目码头位于太平洋西岸,针对矿石散货船的系缆问题,采用OPTIMOOR软件进行分析,确定系泊方案,并计算船舶运动及系泊缆受力情况,计算结果表明,该方案满足系泊要求.     

长三角港口体系结构演变及分货种优势比较

以长三角区域港口为研究对象,采用赫芬达尔-赫希曼指数分析2005—2009年长三角港口的平均集中率和分货种港口的空间集中度,然后从各港口的显示性比较优势和绝对比较优势揭示了各货种在长三角港口内部的转移情况,最后得出在长三角港口体系中,各货种集中程度呈现下降的趋势,集中化程度由高到低依次是:集装箱,石油,天然气及其制品,金属矿石,矿建材料,煤炭。同时上海港集装箱集聚效应加强,散货方面则呈现上海港向周边港口快速扩散、浙江省以宁波-舟山港为龙头集聚效应进一步加强、江苏港口承接转移的同时自身港口结构同步升级调整的特点。