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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society of Marine Engineering
Journal Basic Information
Journal DOI :
Korean Society of Marine Engineers
Editor in Chief :
Volume & Issues
Volume 39, Issue 10 - Dec 2015
Volume 39, Issue 9 - Nov 2015
Volume 39, Issue 8 - Oct 2015
Volume 39, Issue 7 - Sep 2015
Volume 39, Issue 6 - Jul 2015
Volume 39, Issue 5 - Jun 2015
Volume 39, Issue 4 - May 2015
Volume 39, Issue 3 - Mar 2015
Volume 39, Issue 2 - Feb 2015
Volume 39, Issue 1 - Jan 2015
Selecting the target year
Prediction of boil-off gas and boil-off rate in cargo tank of NGH carrier
Kang, Ho-Keunn ; Kim, Dongeum ; Kim, You-Taek ; Park, Jung-Dae ; Kang, Shin-Baek ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 10, 2015, Pages 1002~1010
DOI : 10.5916/jkosme.2015.39.10.1002
Natural gas hydrates are newly emerging as an environment-friendly source of energy to substitute for fossil fuels in the 21stcentury.NGHs are reported to holds much amounts of natural gas (up to 182 standard volumes of gas per volume of hydrate); they are easy to store and safe to carry at about minus 20 degree Celsius under atmospheric pressure because of the self-preservation phenomenon of gas hydrates. The transporting method by gas-ice-hydrate ship carriers has been introduced and developed by a variety of industry and research institutions. Our team has been conducted to develop NGH total systems, including a breakthrough NGH carrier for sea transportation, since 2011. The NGH pellet carrier does not require a separate cooling system for cargo, and the initial temperature is maintained through insulation of the cargo tanks throughout the transport to the final destination. The heat conducted from the exterior and passing through the insulation material of the hull should be cut off as much as possible, but heat inflow inside the cargo tank from an external source is inevitable during transport. In this study, the heat transfer in a cargo tank of a 115K NGH carrier was analyzed through simulation with a commercial CFD code to estimate the boil-off gas/boil-off rate on the developed carrier and understand major hazards that could significantly impact the safety of the vessel.
Non-contact monitoring of 3-dimensional vibrations of bodies using a neural network
Ha, Sung Chul ; Cho, Gyeong Rae ; Doh, Deog-Hee ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 10, 2015, Pages 1011~1016
DOI : 10.5916/jkosme.2015.39.10.1011
Gas piping systems in power plants and factories are always influenced by the mechanical vibrations of rotational machines such as pumps, blowers, and compressors. Unusual vibrations in a gas piping system influence possible leakages of liquids or gases, which can lead to large explosive accidents. Real-time measurements of unusual vibrations in piping systems in situ prohibit them from being possible leakages owing to the repeated fatigue of vibrations. In this paper, a non-contact 3-dimensional measurement system that can detect the vibrations of a solid body and monitor its vibrational modes is introduced. To detect the displacements of a body, a stereoscopic camera system is used, through which the major vibration types of solid bodies (such as X-axis-major, Y-axis-major, and Z-axis-major vibrations) can be monitored. In order to judge the vibration types, an artificial neural network is used. The measurement system consists of a host computer, stereoscopic camera system (two-camera system, high-speed high-resolution camera), and a measurement target. Through practical application on a flat plate, the measured data from the non-contact measurement system showed good agreement with those from the original vibration mode produced by an accelerator.
Hydrodynamic performance of a pump-turbine model in the "S" characteristic region by CFD analysis
Singh, Patrick Mark ; Chen, Chengcheng ; Choi, Young-Do ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 10, 2015, Pages 1017~1022
DOI : 10.5916/jkosme.2015.39.10.1017
Specific hydrodynamic characteristic of pump-turbine during the start and load rejection process of generating mode causes anomalous increase of water pressure, along with large machine vibration, called "S" characteristic. The aim of this study is to understand and explain the hydrodynamic performance of pump-turbine at "S" characteristic region by using a model of pump-turbine system. The operation in the condition of runway and low discharge in a typical "S" characteristic curve may become unstable and complex flow appears at the passage of guide vane and impeller. Therefore, velocity and pressure distribution are investigated to give an all-sided explanation of the formation and phenomenon of this characteristic, with the assistance of velocity triangle analysis at the impeller inlet. From this study, the internal flow and pressure fluctuation at the normal, runway and low discharge points are explored, giving a deep description of hydrodynamic characteristic when the pump-turbine system operates with "S" characteristic.
A study on the modeling of a hexacopter
Le, Dang-Khanh ; Nam, Taek-Kun ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 10, 2015, Pages 1023~1030
DOI : 10.5916/jkosme.2015.39.10.1023
The purpose of this paper is to present the basic mathematical modeling of a hexacopter, which could be used to develop proper methods for stabilization and trajectory control. A hexacopter consists of six rotors with three pairs of counter-rotating fixed-pitch blades. This mechanism is an under-actuated, dynamically unstable, six-degrees-of-freedom system. The whole motion of this object consists of translational and rotational motion in three dimensions, where the translational motion is created by changing the direction and magnitude of the upward propeller thrust. The hexacopter is controlled by adjusting the angular velocities of the rotors, which are spun by electric motors. It is assumed to be a rigid body; thus, the differential equation of the hexacopter dynamics can be derived from the Newton-Euler equation. The Euler-angle parametrization of the three-dimensional rotations contains singular points in the coordinate space that can cause failure of both the dynamical model and control. In order to avoid singularities, the rotations of the hexacopter are parametrized in terms of quaternions. This choice has been made considering the linearity of the quaternion formulation and their stability and efficiency. Further, control simulation of a hexacopter applying cascaded-PID control is also presented in this paper.
Design of RCGA-based PID controller for two-input two-output system
Lee, Yun-Hyung ; Kwon, Seok-Kyung ; So, Myung-Ok ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 10, 2015, Pages 1031~1036
DOI : 10.5916/jkosme.2015.39.10.1031
Proportional-integral-derivative (PID) controllers are widely used in industrial sites. Most tuning methods for PID controllers use an empirical and experimental approach; thus, the experience and intuition of a designer greatly affect the tuning of the controller. The representative methods include the closed-loop tuning method of Ziegler-Nichols (Z-N), the C-C tuning method, and the Internal Model Control tuning method. There has been considerable research on the tuning of PID controllers for single-input single-output systems but very little for multi-input multi-output systems. It is more difficult to design PID controllers for multi-input multi-output systems than for single-input single-output systems because there are interactive control loops that affect each other. This paper presents a tuning method for the PID controller for a two-input two-output system. The proposed method uses a real-coded genetic algorithm (RCGA) as an optimization tool, which optimizes the PID controller parameters for minimizing the given objective function. Three types of objective functions are selected for the RCGA, and each PID controller parameter is determined accordingly. The performance of the proposed method is compared with that of the Z-N method, and the validity of the proposed method is examined.
Electrical system design in FLNG offshore unit
Kim, Jong-Su ; Kim, Deok-Ki ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 10, 2015, Pages 1037~1043
DOI : 10.5916/jkosme.2015.39.10.1037
In recent years, Floating Liquefied Natural Gas (FLNG) Unit have attracted considerable attention. Generally, liquefied natural gas (LNG) units are produced in onshore liquefaction terminals from gas supplied from onshore gas fields or large-scale offshore gas fields near the coast. However, the development of these gas fields has approached saturation. Large-scale offshore gas fields far from the coast, as well as undeveloped medium- and small-scale offshore gas fields, have recently attracted attention. Among several proposed concepts, the floating LNG plant in the form of the FLNG system was chosen for further evaluation and development, considering worldwide receiving infrastructure. The design of a 2.5 million tonne per annum FLNG unit has been completed with a capacity corresponding to that of modern onshore liquefaction plants. Various simulation tests were performed to evaluate the performance of the electrical power plant, focusing on the efficiency of the electrical system to secure the aspects of plant safety. This design study analyzes the electrical system for the FLNG unit to improve the safety of operation and maintenance in the field.
A study on northern sea route navigation using ship handling simulation
Kim, Won Ouk ; Youn, Dae Gwun ; Lee, Young Chan ; Han, Won Heui ; Kim, Jong Su ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 10, 2015, Pages 1044~1048
DOI : 10.5916/jkosme.2015.39.10.1044
Recently, the viability of the Northern Sea Route has been receiving a remarkable amount of attention. Owing to global warming, glaciers in the Arctic Ocean have been melting rapidly, which has opened up navigation routes for ships with commercial as well as research purposes. At present, vessels can be economically operated along the Northern Sea Route four months of the year. However, studies have shown that the economical operating time may increase to six months by 2020 and year-round by 2030. Even though the conditions of the Northern Sea Route are extreme, the main reason for its use is that the route is shorter than the existing route using the Suez Canal, which provides an economic benefit. In addition, 25% of the world's oil reserves and 30% of its natural gas are stored in the coastal areas of the East Siberian Arctic region. Many factors are leading to the expectation of commercial navigation using the Northern Sea Route in the near future. To satisfy future demand, the International Maritime Organization established the Polar Code in order to ensure navigation safety in polar waters; this is expected to enter into force on January 1, 2017. According to the code, a ship needs to reduce its speed and analyze the ice for safe operation before entering into it. It is necessary to enter an ice field at a right angle to break the ice safely and efficiently. This study examined the operation along the course for safe navigation of the passage under several conditions. The results will provide guidelines for traffic officers who will operate ships in the Arctic Ocean.
Justification on engine information in maritime service portfolio for effective implementation of e-Navigation
Lee, Young-Chan ; Sim, Myeong-Bo ; Hong, Woo-Ram ; Lee, Jae-Yeong ; Jung, Byung-Gun ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 10, 2015, Pages 1049~1053
DOI : 10.5916/jkosme.2015.39.10.1049
This paper proposes to include engine information in Maritime Service Portfolio (MSP) for effective implementation of e-Navigation. Even though engine information is one of most important element to e-Navigation, MSP consists of mainly about navigation and communication information not included engine information. Furthermore, in reality, engine information sent from ship side such as mainly noon report and Planned Maintenance System (PMS) is too limited to make e-Navigation possibly. Therefore, Remote diagnostic structure receiving and sending data of engine information must be included in MSP for implementation of e-Navigation. Also, it has to be designed, and developed by Software Quality Assurance (SQA).
A study on the developments of STCW training of seafarers on ships applying in the IGF Code
Han, Se-Hyun ; Lee, Young-Chan ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 10, 2015, Pages 1054~1061
DOI : 10.5916/jkosme.2015.39.10.1054
The International Maritime Organization (IMO) has been regulating emissions by making mandatory the compliance with institutions aimed at protecting air quality such as the Energy Efficiency Design Index (EEDI), Ship Energy Efficiency Management Plan (SEEMP) and Tier III. Under the circumstances, one of the response measures considered to be the most feasible is the replacement of existing marine fuel with Liquefied Natural Gas (LNG). The industry has been preemptively building infrastructure and developing and spreading engine technology to enable the use of LNG-fueled ships. The IMO, in turn, recently adopted the International Code of Safety for Ships Using Gases or Other Low-Flash-Point Fuels (IGF Code) as an institutional measure. Thus, it is required to comply with regulations on safety-related design and systems focused on response against potential risk for LNG-fueled ships, in which low-flash-point fuel is handled in the engine room. Especially, the Standards of Training, Certification and Watchkeeping (STCW) Convention was amended accordingly. It has adopted the qualification and training requirements for seafarers who are to provide service aboard ships subject to the IGF Code exemplified by LNG-fueled ships. The expansion in the use of LNG-fueled ships and relevant facilities in fact is expected to increase demand for talents. Thus, the time is ripe to develop methods to set up appropriate STCW training courses for seafarers who board ships subject to the IGF Code. In this study, the STCW Convention and existing STCW training courses applied to seafarers offering service aboard ships subject to the IGF Code are reviewed. The results were reflected to propose ways to design new STCW training courses needed for ships subject to the IGF Code and to identify and improve insufficiencies of the STCW Convention in relation to the IGF Code.
Performance evaluation of sea water heat exchanger installed in the submerged bottom-structure of floating architecture
Sim, Young-Hoon ; Hwang, Kwang-Il ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 10, 2015, Pages 1062~1067
DOI : 10.5916/jkosme.2015.39.10.1062
Floating architecture is a type of building that is geographically located on a sea or a river. It floats under the influence of buoyancy, and does not have an engine for moving it. Korea is a peninsula surrounded by sea except on the north side, so floating architectures have been mainly focused on two points: solving the issue of small territory and providing various leisure & cultural spaces. Floating architectures are expected to save energy effectively, if they use sea water heat, which is known to be clean energy with infinite reserves. To use sea water heat as the heat source and/or heat sink, this study proposes a model in which a sea water heat exchanger is embedded in the concrete structure in the lower part of the floating architecture that is submerged under the sea. Based on the results of performance evaluations of the sea water heat exchanger using CFD (computational fluid dynamics) analysis and mock-up experiments under various conditions, it is found out that the temperature difference between the inlet and outlet of the heat exchanger is in the range of
, and that the quantity of heat transfer measured is in the range of 3,812~7,180 W. The CFD evaluation results shows a difference of 5% with respect to the results of mock-up experiment.