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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society of Marine Engineering
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Journal DOI :
Korean Society of Marine Engineers
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Volume & Issues
Volume 40, Issue 6 - Jul 2016
Volume 40, Issue 5 - Jun 2016
Volume 40, Issue 4 - May 2016
Volume 40, Issue 3 - Mar 2016
Volume 40, Issue 2 - Feb 2016
Volume 40, Issue 1 - Jan 2016
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Analytical solution of the Cattaneo - Vernotte equation (non-Fourier heat conduction)
Choi, Jae Hyuk ; Yoon, Seok-Hun ; Park, Seung Gyu ; Choi, Soon-Ho ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 5, 2016, Pages 389~396
DOI : 10.5916/jkosme.2016.40.5.389
The theory of Fourier heat conduction predicts accurately the temperature profiles of a system in a non-equilibrium steady state. However, in the case of transient states at the nanoscale, its applicability is significantly limited. The limitation of the classical Fourier's theory was overcome by C. Cattaneo and P. Vernotte who developed the theory of non-Fourier heat conduction in 1958. Although this new theory has been used in various thermal science areas, it requires considerable mathematical skills for calculating analytical solutions. The aim of this study was the identification of a newer and a simpler type of solution for the hyperbolic partial differential equations of the non-Fourier heat conduction. This constitutes the first trial in a series of planned studies. By inspecting each term included in the proposed solution, the theoretical feasibility of the solution was achieved. The new analytical solution for the non-Fourier heat conduction is a simple exponential function that is compared to the existing data for justification. Although the proposed solution partially satisfies the Cattaneo-Vernotte equation, it cannot simulate a thermal wave behavior. However, the results of this study indicate that it is possible to obtain the theoretical solution of the Cattaneo-Vernotte equation by improving the form of the proposed solution.
Performance characteristic investigation and stay vane effect on N
100 inline francis turbine
Singh, Patrick Mark ; Chen, Zhenmu ; Hwang, Yeong-Cheol ; Kang, Min-Gu ; Choi, Young-Do ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 5, 2016, Pages 397~402
DOI : 10.5916/jkosme.2016.40.5.397
This study presents the performance characteristics of a small Francis turbine with an inline casing and is a continuation of a previous study. A new runner design has been implemented using the previous facility. The specific speed of the new runner has been modified from
. This turbine can be installed in a city water supply system. To dissipate excess pressures in the water line system an inline-turbine can be used instead of an inline-pressure reducing valve. Thus, some of the energy can be recovered by utilizing the pressure difference. For best applicability and minimal space consumption, the turbine is designed with an inline casing instead of a common spiral casing. As a characteristic of inline casing, the flow accesses to the runner are in the radial direction, showing low efficiency. The installation of vanes improves the internal flow and positively affects the output power. In contrast to the previous study, the new runner reduces the effect of the stay vanes by maintaining a higher efficiency.
Study on velocity profiles around spiral baffle plates in a horizontal circular tube without inner tubes
Chang, Tae-Hyun ; Lee, Kwon-Soo ; Choi, Yoon-Hwan ; Lee, Yeon-Won ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 5, 2016, Pages 403~411
DOI : 10.5916/jkosme.2016.40.5.403
Usually shell and tube heat exchangers are employed to recover energy between fluids. Recently, numerous papers on these heat exchangers have been published; however, the velocity and temperature profiles or comparison of the features of the flow with or without inside tubes have rarely been described. In this research, experimental and numerical studies were carried out to investigate the characteristics of the flow around the spiral baffle plates without inside tubes in a horizontal circular tube using a particle image velocimetry method and ANSYS 14.0~15.0 version (Fluent). The results showed that swirling flow was produced between the spiral baffle plates. The tangential components were strong between the two spiral baffles; however, the axial or radial velocities components were indicating nearly zero. From the spiral motion in the space of the two baffles, it is considered that there were no dead zones between the spiral baffle.
Numerical analysis of natural convection heat transfer from a fin in parallel enclosure
Bae, Myung-Whan ; Mochimaru, Yoshihiro ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 5, 2016, Pages 412~417
DOI : 10.5916/jkosme.2016.40.5.412
A fin of finite width with infinitely small thickness is assumed to be placed horizontally between two horizontal parallel plates of infinite extension in the exactly central position. The lower plate and the half of the upper plate are kept at a constant lower temperature, and the remaining upper plate is kept at a constant higher temperature. The fin is also kept at a constant temperature (variable). Steady-state two-dimensional laminar natural convection is analyzed as a problem of boundary value under a boundary-fitted conformal mapping system, using a spectral finite difference scheme, with a condition of doubly-connectedness. The steady-state solution is obtained as a limit of the transient solution.
Study on development of vessel shore report management system for IMO MSP 8
Rind, Sobia ; Mo, Soo-Jong ; Yu, Yung-Ho ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 5, 2016, Pages 418~428
DOI : 10.5916/jkosme.2016.40.5.418
In this study, a Vessel Shore Report Management System (VSRMS) is developed for the International Maritime Organization (IMO), Maritime Service Portfolio (MSP) Number 8, which comprises vessel shore reporting. Several documents have to be completed before the arrival/departure of a vessel at a port, as each national port has its own reporting format and data. The present vessel reporting system is inefficient, time-consuming, and involves excessive paperwork, which results in duplications and errors. To solve this problem, in this study, the vessel reporting formats and data contents of various national ports are investigated, as at present, the reporting documents required by the current IMO standard includes insufficient information which is requested by national ports. Initially, the vessel reporting information of various national ports are collected and analyzed. Subsequently, a database structure for managing vessel reporting data for ports worldwide is devised. To make the transfer of data and the exchange of information of vessel reports much more reliable, efficient, and paper-free, VSRMS, which is a software application for the simplification and facilitation of vessel report formalities, is developed. This application is developed using the latest Microsoft C#.Net Programming Language in the Microsoft Visual Studio framework 4.5. It provides a user interface and a backend MySQL server used for database management. SAP Crystal Reports 2013 is used for designing and generating vessel reports in the original report formats. The VSRMS can facilitate vessel reporting and improve data accuracy through the reduction of input data, efficient data exchange, and reduction of the cost of communication. Adoption of the VSRMS will allow the vessel shore reporting system to be automated, resulting in enhanced work efficiency for shipping companies. Based on this information system and architecture, the consensus of various international organizations, such as the IMO, the International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA), the Federation of National Associations of Ship Brokers and Agents (FONASBA), and the Baltic and International Maritime Council (BIMCO), is required so that vessel reporting is standardized internationally.
Design of a hybrid power management system and cold start simulation in a fuel cell ship with PLECS
Oh, Jin-Seok ; Kang, Young-Min ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 5, 2016, Pages 429~436
DOI : 10.5916/jkosme.2016.40.5.429
Currently, many studies on green ships are under way. Fuel cell (FC) ships are of interest as future low-emission, fuel-efficient vessels. In this paper, a hybrid power management system for an FC ship was designed. The system consists of an FC, a battery, a unidirectional DC/DC converter, a bidirectional DC/DC converter, a filter, an inverter, and a propulsion component. To design the system, we analyze electric sources and converters, and create PLECS models of hybrid power management system. Then, we check the cold start sequence and perform a simulation to understand the characteristics of the hybrid power management system in an FC ship.
A comparative study of filter methods based on information entropy
Kim, Jung-Tae ; Kum, Ho-Yeun ; Kim, Jae-Hwan ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 5, 2016, Pages 437~446
DOI : 10.5916/jkosme.2016.40.5.437
Feature selection has become an essential technique to reduce the dimensionality of data sets. Many features are frequently irrelevant or redundant for the classification tasks. The purpose of feature selection is to select relevant features and remove irrelevant and redundant features. Applications of the feature selection range from text processing, face recognition, bioinformatics, speaker verification, and medical diagnosis to financial domains. In this study, we focus on filter methods based on information entropy : IG (Information Gain), FCBF (Fast Correlation Based Filter), and mRMR (minimum Redundancy Maximum Relevance). FCBF has the advantage of reducing computational burden by eliminating the redundant features that satisfy the condition of approximate Markov blanket. However, FCBF considers only the relevance between the feature and the class in order to select the best features, thus failing to take into consideration the interaction between features. In this paper, we propose an improved FCBF to overcome this shortcoming. We also perform a comparative study to evaluate the performance of the proposed method.
Case study on operating characteristics of gas fueled ship under the conditions of load variation
Chun, Jung-Min ; Kang, Ho-Keun ; Kim, You-Taek ; Jung, Mun-Hwa ; Cho, Kwon-Hae ;
Journal of the Korean Society of Marine Engineering, volume 40, issue 5, 2016, Pages 447~452
DOI : 10.5916/jkosme.2016.40.5.447
The use of gas as fuel, particularly liquefied natural gas (LNG), has increased in recent years owing to its lower sulfur and particulate emissions compared to fuel oil or marine diesel oil. LNG is a low temperature, volatile fuel with very low flash point. The major challenges of using LNG are related to fuel bunkering, storing, and handling during ship operation. The main components of an LNG fuel system are the bunkering equipment, fuel tanks, vaporizers/heaters, pressure build-up units (PBUs), and gas controlling units. Low-pressure dual-fuel (DF) engines are predominant in small LNG-powered vessels and have been operating in many small- and medium-sized ferries or LNG-fueled generators.(Tamura, K., 2010; Esoy, V., 2011) Small ships sailing at coast or offshore rarely have continuous operation at constant engine load in contrast to large ships sailing in the ocean. This is because ship operators need to change the engine load frequently due to various obstacles and narrow channels. Therefore, controlling the overall system performance of a gas supply system during transient operations and decision of bunkering time under a very poor infrastructure condition is crucial. In this study, we analyzed the fuel consumption, the system stability, and the dynamic characteristics in supplying fuel gas for operating conditions with frequent engine load changes using a commercial analysis program. For the model ship, we selected the 'Econuri', Asia's first LNG-powered vessel, which is now in operation at Incheon Port of South Korea.