共查询到20条相似文献,搜索用时 15 毫秒
1.
Assessing the sloshing loads has been a significant issue in designing the cargo containment system (CCS) of a liquefied natural gas carrier (LNGC). The sloshing problem contains numerous physical and technical uncertainties. The long-term approach has been suggested to reduce the possible uncertainties, but it has not been a feasible option owing to the incalculable number of experimental cases. Daewoo Shipbuilding and Marine Engineering Co., Ltd., Hyundai Heavy Industry Co., Ltd., Samsung Heavy Industry Co., Ltd., Korean Register, and Seoul National University conducted extensive sloshing model tests for the 174 K S-LNGC. To consider the long-term approach, Part I describes the differences between short- and long-term approaches based on the guidelines of different classification societies. To address the significant number of experimental conditions required for the long-term approach, a grouping method is investigated (Part II). Although this grouping method is typically used in practical design, it has not been validated, and its applicability is yet to be determined. In Part II, the sea states are classified using 16 different grouping methods. The long-term exceedance probabilities and pressures are obtained individually and then compared with the results obtained from fully considering all sea states. After performing the general sloshing model test of the shipbuilding industry, the sloshing impact pressure of a liquefied natural gas cargo model is measured via 6DoF irregular simulations, where the upper section of the cargo hold structure is considered. Long-term pressures are locally and globally investigated and compared among 16 different sea states and all the sea states. Based on the results, the best grouping method is suggested for the long-term approach. 相似文献
2.
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 ≤ hB/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. 相似文献
3.
4.
5.
6.
As environmental regulations have become more onerous, the demand for LNG and LNG carriers has increased. The LNG cargo containment system (LNG CCS) is one of the most important facilities in LNG carriers, and many membrane types of LNG CCS have been developed so far. Traditionally, sloshing model tests are performed and a series of statistical approaches are used to obtain design sloshing pressures. Then, these design loads are utilized to analyze the structural safety of LNG CCS. In the sloshing model test, the flat and almost rigid plate is used as the LNG CCS instead of a real model, and thus, the hydroelasticity effect cannot be considered. In the present research, the effect of hydroelasticity on sloshing pressure was investigated in a fluid-structure interaction simulation. A wet drop simulation was conducted, and its results subsequently were compared with wet drop experimental test results to ensure their validity. Then, two types of structure model, namely a flat-rigid plate model and a flat-flexible CCS model, were generated to investigate the effect of hydroelasticity. Also, a fluid hitting analysis model was devised to realize the sloshing phenomenon, and the two generated structure models were applied as the structure domain in the analysis. In the fluid hitting simulations, it was found that the hydroelasticity effect on sloshing pressure is significant. Thus, correction factors, which are quantitative values of the effect of hydroelasticity, were derived (and are proposed herein). Finally, a structural safety assessment procedure for consideration of the hydroelasticity effect was derived (and is suggested herein). 相似文献
7.
对江南长兴重工有限公司5100TEU集装箱船设计和建造过程中出现的结构修改引起箱位数变化的处理、首部过尖采用铸件、三向结构通断、高应力区典型节点考虑、船首1/4L货舱通风帽结构布置5个重要技术问题作了分析,以期对今后类似问题的处理有所借鉴。 相似文献
8.
钢结构大厦工程的控制管理 总被引:1,自引:0,他引:1
阐述了在江南重工股份有限公司承接的国内第一幢"全国产化"大楼——长春光大银行营业大厦钢结构工程的项目管理中,如何实施工程管理控制的方法和经验。 相似文献
9.
10.
文章将KdV、eKdV和MCC内孤立波理论应用到内孤立波数值模拟水槽入口速度条件计算,讨论内孤立波与浮式生产储卸油装置FPSO强非线性作用问题。结果表明,数值模拟所得FPSO内孤立波水平载荷、垂向载荷及力矩与实验结果相吻合,内孤立波载荷主要由波浪压差力、粘性压差力和摩擦力构成,粘性压差力很小,可以忽略;在水平载荷中,摩擦力较压差力约小一个量级,流体粘性的影响不可忽略;在垂向载荷中,摩擦力比压差力小很多,在分析时可以忽略流体粘性的影响。由于FPSO始终处于上层流体中,对内孤立波的模拟波形和其诱导流场的影响很小。波浪压差力可利用傅汝德-克雷洛夫公式基于动压力进行计算,而水平载荷中的摩擦力则需根据内孤立波诱导速度的切向分量对FPSO吃水湿表面求积分的方法进行计算。 相似文献
11.
12.
倪永亮 《船舶标准化工程师》2020,53(3):42-44,82
文章对大连中远海运重工有限公司建造的18000m^3耙吸式挖泥船电气系统进行了简要介绍,根据挖泥船的特点,对挖泥作业特有的系统进行了简要说明,对今后类似船舶的建造具有参考意义。 相似文献
13.
本文在作者已有的二维改进MPS(Moving Particle Semi-implicit)方法基础上进行了三维拓展(主要包括三维自由面粒子判断),并通过将计算得到的三维溃坝问题结果与文献中实验结果相对比,验证了所发展模型的准确性。在结构响应计算方面,将刚性和柔性模态耦合并计及相互影响。在此基础上,将流体和结构部分通过迭代方式耦合,从而实现强流固耦合计算。最后,应用上述模型对涉及大刚体位移叠加弹性变形的三维方梁的强非线性时域水弹性问题进行了计算,验证了模型对此类问题的有效性。 相似文献
14.
Database of the sloshing model test has been mined. More than 540 terabytes experimental data have been accumulated for various cargo holds, vessels, environmental conditions, operational conditions, and experimental conditions. The database was organized, cleaned, and analyzed for the floating units larger than standard size LNG carriers or LNG fueled vessels. The selected target data was used for the machine learning to predict the model test results from the test conditions. An artificial neural network has been developed. Many different types of parameters were scaled and transformed as the input attributes followed by the optimization of the hyperparameters and the architecture. The network predicted the test results that were not used in the training process. The prediction results were validated according to the changes in the environmental conditions, operational conditions, and model dimensions. The accuracy of the network was acceptable to be applicable to the designing perspective. 相似文献
15.
16.
Sloshing phenomenon in the liquid cargo carriers has caught the attention of researchers as the interaction between the sloshing
waves and structure is one of the key point and difficulty in the study of sloshing. In this paper, we captured the free surface
with a volume of fluid (VOF) method and then calculated the motions and responses of the structure by adopting the Reynolds-averaged
Navier-Stokes (RANS) equations for the whole fluid domain. With the use of user defined functions (UDF) in Fluent, the interaction
between fluid and structure was then simulated. As a reasonable simplification, the authors studied the response of a single
cantilever in a tank under sloshing loads; Further study should pay more attention to the mechanisms of interaction between
sloshing waves and elastic structures. 相似文献
17.
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. 相似文献
18.
为提高内陆散粮的装卸效率,大连港集装箱发展有限公司开发了"散改集"装卸工艺,并研发了门式倾转机。介绍内陆"散改集"主要工艺和该公司对工艺的改革和创新。介绍了门式倾转机的功能与特点。该研究成果取得良好的经济效益和社会效益,可为其它港口和行业提供技术借鉴。 相似文献
19.
20.
文章介绍了中海工业(上海长兴)有限公司在“海联昌兴”轮舵系修理过程中的修理工艺及校中方法的比较,为以后相似船舶的修理提供了良好的借鉴。 相似文献