A Study on the Relation Between Flow-Induced Noise and

Vortex Release Frequency of Propellers

 

YANG Zhenyu, YAO Huilan, ZHANG Huaixin

（Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration,

Shanghai Jiao Tong University, Shanghai 200240, China）

 

Abstract: Flow-induced vibration can cause non-linear flow-induced noise and leads to the phenomenon of “singing” in case it occurs seriously, which will have a great impact on the operation of ships. In this paper, the pressure of propeller blade along the edge is analyzed based on the user-defined function to obtain the vortex release frequency. The acoustic boundary element method is used to predict and compare the propeller noise that occurred when the vortex release frequency is close to or far from the propeller natural frequency. The results show that there are many lines near the vortex release frequency, which form a region of vortex release frequency, and the propellers with different elastic modulus are corresponding to different natural frequencies. When the natural frequencies of a certain order are close to the region, the noise generated by the propeller is about 20 dB higher than that generated far away.

Key words:flow-induced vibration; propeller noise; singing; resonance

 

 

 

Optimization of Comprehensive Performance for a Feeder

Container Ship under Multiple Operation Conditions

 

JIANG Weidong

（COSCO Shipping Heavy Industry Co., Ltd., Shanghai 200135,China）

 

Abstract: As feeder container ship has the features of short voyage, multiple loading situation and variable speed, performance optimization of a single operating point cannot meet the requirements of energy saving in actual operation.  Optimizations on three types of hull lines, three propeller designs and three sorts of rudder blade are performed with a feeder container ship as example, where the ship’s actual operation profile is taken into account. The results are validated by Computational Fluid Dynamics (CFD) analysis and ship model experiments, which determines the optimal combination of hull line, propeller and rudder blade, and realizes the optimization of main engine average operating power, loading capacity, service speed and the Energy Efficiency Design Index (EEDI). This improves significantly the energy efficiency of the ship, and brings benefits of economy and environmental protection.

Key words:multiple operation conditions; comprehensive performance optimization; feeder container ship; Energy Efficiency Design Index

 

 

 

A Study on the Hydrodynamic Characteristics of

Pile Foundations of Offshore Wind Farms

 

XIE Qidi¹, ZHANG Meiman², BAO Xiongguan²

（1. Ningbo Tianyi Shipping Company, Ningbo 315000, China；

2. Faculty of Maritime and Transportation, Ningbo University, Ningbo 315000, China）

 

Abstract: The offshore wind turbine influences greatly the hydrodynamic characteristics of wind farm waters. Based on OpenFOAM software, this study simulates the flow characteristics of a two-dimensional cylinder using the improved RANS model. The flows around the cylinder are simulated under different Reynolds numbers, and the lift-drag coefficients and the flow fields are analyzed. The result shows that the drag coefficients increase or decrease abruptly, but the periodicity is not obvious, the variation patterns of drag coefficients are similar under different Reynolds numbers and have the same amplitudes; the lift coefficients oscillate periodically around zero, and the amplitudes are not stable; the variation pattern of the amplitudes under different Reynolds numbers is different, but the variations are the same; and the influence of the cylinder on the flow characteristics is time dependent. The wind farm foundation and the wake flow structure in front of the structure are both time-related.

Key words:offshore wind turbine; OpenFOAM software; flow around cylinder; hydrodynamics

 

 

 

Pretension Calculation of the Main Bearing Shell

Connecting Bolt of a Low-Speed Engine

 

WANG Kui, DONG Jingjin, TU Danhong

（China Shipbuilding Power Engineering Institute Co., Ltd., Shanghai 200129, China)

 

Abstract: In order to determine the proper pretension for the connecting bolt of the main bearing cap, the main bearing shell of a low speed engine is taken as the research object to analyze the relationship between the resulting tangential forces and the bearing shell stiffness, its tolerance and its protrusion in the installation of the main bearing shell of an engine by theoretical calculation and simulation respectively. The similarities and differences between the two methods involved in calculation of the parameters are compared, and the connecting bolt pretension calculation method for the installation of main bearing shell of low speed diesel engines is determined afterwards, which provides reference for the determination of pretensions in such applications.

Key words:low speed engine; main bearing shell; bearing shell tangential force; connecting bolt; pretension

 

 

 

Selection of Retrofitted

Ballast Water Management System for a VLCC

 

ZHAO Chunji¹, ZHAO Lina², AN Chao³

1. Sinotrans Container Line Co., Ltd., Shanghai 200001, China;

2. Animal and Plant and Food Inspection and Quarantine Technology Center,

ShanghaiInspection and Quarantine Bureau Shanghai 200135, China

3. Merchant Marine College, Shanghai Maritime University, Shanghai 201316, China.)

 

Abstract: To deal with the problem of diversity and complexity in selecting ship Ballast Water Management System (BWMS), this paper takes a Very Large Crude Carrier (VLCC) in service as the research object to study the selection of BWMS using the Analytic Hierarchy Process-Technique for Order Preference by Similarity to an Ideal Solution (AHP-TOPSIS) method and the Fuzzy Analytic Hierarchy Process (FAHP) method, respectively. The result shows that the optimal solutions given by the two methods are identical, and both are suitable for VLCC’s BWMS selection. However, when there is no actual data and the selection can only be accomplished according to expert’s evaluation, the FAHP method is superior to the AHP-TOPSIS method to approximate the ideal solution for the selection of such equipment.

Key words:Very Large Crude Carrier (VLCC); Ballast Water Management System (BWMS); equipment selection

 

 

 

Design of Close Bus-tie Power System under DP-2 Condition

 

SUN Zhe¹, WANG Kehu², XU Nan¹

（1. CSSCCCruise Technology Development Co., Ltd., Shanghai 200137, China;

2. ShanghaiWaigaoqiao Shipbuilding Co., Ltd., Shanghai 200137,China）

 

Abstract: This paper introduces the applications of closed bus-tie power systems on offshore platforms or special purpose vessels with Dynamic Positioning-2 (DP-2) notation. The design requirements and key points of the closed bus-tie power system with DP-2 notation are elaborated regarding the overload protection design, the speed regulator design, the short circuit ride through design and etc, to determine a typical design scheme of the closed bus-tie power system satisfying DP-2 requirements.

Key words:DP-2notation; closed bus-tie; isolated island mode; short circuit ride through; voltage drop

 

 

 

Research and Simulation of the Viable Frequency Speed Regulation Hydraulic System for Seafloor Unmanned Vehicle

 

GUO Hao

（Institute of Marine Equipment and Technology,

Jiangsu University of Science and Technology, Zhenjiang 212003, China）

 

Abstract: A viable frequency speed regulation hydraulic system is designed for the walking mechanism of seafloor heavy duty unmanned vehicle based on the seafloor operating situation, and the AMESim numerical model of the system is established. The parameters of Proportion-Integration-Differentiation (PID) controller are tuned during simulation, and its dynamic switching process is analyzed. The result shows that the hydraulic system designed has excellent dynamic response characteristics. This study provides a theoretical basis for the design optimization of hydraulic system and control strategy investigation of the seafloor heavy duty unmanned vehicle's walking mechanism.

Key words:deep-sea mining; viable frequency speed regulation; hydraulic transmission; heavy-duty unmanned vehicle; simulation

 

 

 

Curved Plate Inspection Technology Based on Digital Measurement

 

FAN Hongliang, LIU Yanping, QIN Gong

（Hudong-Zhonghua Shipbuilding (Group) Co., Ltd., Shanghai 200129, China）

 

Abstract: To meet the demand of digital inspection of the curved plate surface, the real-time relationship between the measured surface and the actual hull plate is established and the deviations are computed and fed back by creating local fast measuring system to collect the 3D coordinates of the surface, and forming point cloud data for the comparison with the theoretical model after 3D coordinate transformation. This inspection technology can replace the traditional sample plate and sample box measurement method to realize the effective and all-around inspection, which not only increases the measurement accuracy but also improves the analysis efficiency of the curved plate processing deviations. The study provides technical support for the precision control of curved plates, and also provides data for their subsequent rectification process improvement.

Key words:curved plate inspection system; precision control; secondary lining; alignment of data

 

 

 

Fracture Analysis of Marine Metal under Axial Tension

Based on Gurson Model

 

WANG Jiangchao, ZHUO Zichao, XIONG Jiawei

（School of Naval Architecture and Ocean Engineering,

Huazhong University of Science and Technology, Wuhan 430074, China）

 

Abstract: Marine structures have the risk of fracture caused by external loads so the fracture behavior of marine metal under axial tension is numerically analyzed with Gurson model. This paper elaborates the Gurson model and its theory, and implements its function based on C++ language. The influence of initial defection ratio, external loads, elastic modulus of the material and the anti-fracture performance on the metal test piece's fracture is studied. The comparison of the results from the tests of Q235 and the aluminum alloy under axial tension has shown a good agreement which demonstrates that the proposed computational approach is feasible for structural fracture performance assessment and the code is reliable.

Key words:fracture under axial tension;Gurson model;void nucleation and growth;plastic strain; marine metal

 

 

 

Hoisting Technology Assessment Based on Wooden Block and

Epoxy Resin Protection for 85000m³ VLEC

 

XIE Jiguang, HONG Wei, TAO Hui

（ECONOVO Marine Engineering Company, Shanghai 200030, China）

 

Abstract: An assessment of the gap and slipping value inside the saddles is performed for hoisting operation to eliminate or minimize the risk of local crack in the fixed epoxy resin base or the wooden block. The finite element analysis is carried out for the lifting on water and the lifting in dock with an 85000m³Very Large Ethane Carrier (VLEC) as the example. The range and magnitude of the gap and the slipping are calculated and evaluation for the damage of the epoxy resin or wooden block is made. It is found through comparison that the gap caused by the lifting of deck mega block on water is larger and hard to control. The maximum gap could reach 2mm, and it is still over 1mm even after the lifting process is improved. The hull girder load due to the uneven distribution of the weight and buoyancy is the main cause for the oversized gap. As there is not obvious hull girder load when lifting in dock, the gap can be basically eliminated if a good docking block arrangement is proposed. To ensure the quality of the epoxy casting, it is suggested that the deck block closure is better to be accomplished in the dry dock, and it should be done after the epoxy is fully cured. If the deck block has to be assembled on water, it is suggested that the bottom ballast tanks should be filled water to reduce the hull deformation due to hogging moment.

Key words:type C independent tank; hoisting; epoxy resin; wooden block; crack; gap; finite element analysis

 

 

 

Key Technologies for Construction of

Stern Door and Gangplank of the Access System

 

LIU Ming, LIU Jian, QI Bin

（Hudong-Zhonghua Shipbuilding (Group) Co., Ltd., Shanghai 200129, China)

 

Abstract: In order to improve the construction accuracy of the stern door and gangplank of access system, three key factors affecting the construction accuracy are investigated, i.e. the accuracy of structures, the concentricity between the hinge boring and the shaft hole, and the watertight control. It is the key technology which assures that the stern door and the gangplank are successfully constructed and delivered, the quality of construction and installation is improved, the construction cycle is shortened and the hull is guaranteed to be waterproof. This study provides reference for the construction and installation of similar stern doors and gangplanks.

Key words:stern door; gangplank; technology; control; quality of construction

 

 

 

Intelligent Manufacture Planning for

Marine Engineering Structural Pipe Workshop

 

QIAN Weixin

（China Shipbuilding NDRI Engineering Co., Ltd., Shanghai 200063, China）

 

Abstract: Structural pipe is an important part of marine engineering products. Under the background of "intelligent manufacturing", the demand for automation and intelligence manufacture by China's marine engineering enterprises are growing as the traditional mode of production cannot meet the needs of production. In order to improve the production mode, three layout schemes for structural pipe workshop are put forward after the production process is studied. Then the comparative analysis is carried out to find out the optimal layout scheme and a typical marine engineering assembly plant is taken as the example to arrange the intelligent equipment based on the optimal scheme. It is verified by simulation that the optimal scheme is superior.

Key words:pipe workshop; structural pipe; intelligent manufacturing; planning scheme

 

 

 

Multi-Disciplinary Digital Collaborative Opening Technology and

System for Ships

 

LIU Yongzhen, ZHANG Xin, YANG Yigan, LEI Hongtao, HU Zhixian

（Jiangnan Shipyard (Group) Co., Ltd., Shanghai 201913, China)

 

Abstract: This paper studies the multi-disciplinary collaborative opening design management and the hole opening technology based on knowledge engineering. By controlling the opening profile and the opening application sheet status, the data sharing and design status management are realized for the collaborative design process. The knowledge engineering method is used to realize the automatic calculation of the profile and batch opening of structures. The result of practical application shows that the achievement can not only realize the process driven design, but also ensures high design efficiency and accuracy.

Key words:3D-experience platform; knowledge engineering; opening management; opening profile

 

 

 

Research and Application of Electronic Material Picking

Technology for Ship Equipment Management

 

LI Shujun, TANG Jun, WANG Feng, ZHANG Lei

（CSSC Huangpu Wenchong Shipbuilding Co., Ltd., Guangzhou 511462, China）

 

Abstract: An integrated material management model is designed to improve the efficiency and accuracy of ship equipment material management, which explored the approach and method to realize the electronic material picking of ship equipment so as to form the standardized management process and achieve the refined management of ship equipment material. It lays the foundation for the development of high quality ship construction.

Key words:refined management; electronic material picking; material management

 

 

 

Risk of Solitary Internal Waves on the Operation of Dynamic Positioning Vessel and Its Countermeasures

 

CHEN Shuai, YU Jinlin, WANG Jingkai, LIU Guozeng

（COOEC Subsea TechnologyCo., Ltd., Shenzhen 518067, China)

 

Abstract: This paper discusses the influence of solitary internal wave on the dynamic positioning vessel in operation by analyzing the distribution and mechanism of solitary internal waves and the operation principles of Dynamic Positioning (DP) vessels. Based on the experience of dealing with internal waves, the countermeasures are elaborated from three aspects, i.e., the observation approach, the pre-operation preparation and the on-site response. The feasibility of the measures is validated through the analysis of the actual countermeasure scheme for a DP2 mooring operation engineering vessel.

Key words:dynamic positioning vessel; solitary internal wave; south of China Sea; countermeasure