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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 33, Issue 8 - Nov 2009
Volume 33, Issue 7 - Nov 2009
Volume 33, Issue 6 - Sep 2009
Volume 33, Issue 5 - Jul 2009
Volume 33, Issue 4 - May 2009
Volume 33, Issue 3 - May 2009
Volume 33, Issue 2 - Mar 2009
Volume 33, Issue 1 - Jan 2009
Selecting the target year
Water Freezing Behavior in a Rectangular Vessel Cooled from Below Direction
Kim, Myoung-Jun ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 4, 2009, Pages 443~450
DOI : 10.5916/jkosme.2009.33.4.443
This study has dealt with the ice making characteristics in a rectangular vessel cooled from below direction with experiment and numerical analysis. The experiment and numerical analysis were carried out under the following conditions which are the cooling wall temperatures of -5[
], and -15[
]. The temperature profile of non-frozen layer was calculated by numerical analysis as the form of non-dimensional temperature. From this study, it is cleared that the existence of natural convection is clearly known. And also the non-dimensional freezing amount was derived from experimental result. This correlation equation will give a useful information to the designers of ice making system.
A Study on the Spray Characteristics of Flash Boiling Using Two Component Mixing Fuel
Myong, Kwang-Jae ; Yoon, Jun-Kyu ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 4, 2009, Pages 451~458
DOI : 10.5916/jkosme.2009.33.4.451
This experimental study was conducted to investigate macroscopic characteristics of the flash boiling spray with tow component mixing fuel. Homogeneous Charge Compression Ignition (HCCI) is a newer combustion method for internal combustion engines to reduce nitrogen oxide and particulate matter simultaneously. But it is difficult to put this combustion method to practical use in an engine because of such problems as instability of combustion in low load operating conditions and knocking in high load operating conditions. In HCCI, combustion characteristics and exhaust emissions depend on conditions of air/fuel mixture and chemical reactions of fuel molecules. The fuel design approach is achieved by mixing two components which differ in properties such as density, viscosity, volatility, ignitability and so on. We plan to apply the fuel design approach to HCCI combustion generated in a real engine, and examine the possibility of mixture formation control using the flash boiling spray. Spray characteristics of two component fuel with a flash boiling phenomenon was investigated using Shlieren and Mie scattering photography. Test fuel was injected into a constant volume vessel at ambient conditions imitated injection timing BTDC of a real engine. As a result, it was found that a flash boiling phenomenon greatly changed spray structure, especially in the conditions of lower temperature and density. Therefore, availability of mixture formation control using flash boiling spray was suggested.
Performance Analysis of R744 (Carbon Dioxide) Transcritical Refrigeration System Using Internal Heat Exchanger
Son, Chang-Hyo ; Oh, Hoo-Kyu ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 4, 2009, Pages 459~465
DOI : 10.5916/jkosme.2009.33.4.459
This paper considers the influence of internal heat exchangers to the efficiency of a refrigerating system. These internal heat exchangers(liquid-suction or suction-line heat exchangers) can, in some cases, yield improved system performance while in other cases they degrade system performance. A steady state mathematical model is used to analysis the performance characteristics of refrigeration system with internal heat exchanger. The influence of operating conditions, such as gas cooler pressure and evaporation temperatures, superheat in the evaporator and temperature of gas cooler outlet, to optimal dimensions of the heat exchanger is also analyzed in the paper. The main results were summarized as follows : the mass flowrate of R744, inner diameter tube and length of internal heat exchanger, and effectiveness have an effect on the cooling capacity, compressor work and RCI(Relative capacity index) of this system. With a thorough grasp of these effect, it is necessary to design the R744 compression refrigeration cycle using internal heat exchanger.
The Characteristics of the Flame Propagation Velocity and Volume Integral of Reaction Rate with the Variation of Fuel Injection Velocity for a Liftoff Flame
Ha, Ji-Soo ; Kim, Tae-Kwon ; Park, Jeung ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 4, 2009, Pages 466~475
DOI : 10.5916/jkosme.2009.33.4.466
A numerical analysis of reactive flow in a liftoff flame is accomplished to elucidate the characteristics of flame propagation velocity and volume integral of reaction rate with the variation of fuel injection velocity at the fuel rich region, fuel lean region and diffusion flame region. The increase of fuel injection velocity enhances flame propagation velocity, but its effect on the flame propagation velocity is not much greater under 4%. The increase of fuel injection velocity affects directly and linearly on the flame surface area in the fuel rich region and so enhances volume integral of reaction rate to accommodate the increment of fuel.
Development of Simulation Tool for Dynamic Behavior of a Linear Compressor
Jeon, Soo-Hong ; Jeong, Weui-Bong ; Lee, Hyo-Jae ; Kim, Dang-Ju ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 4, 2009, Pages 476~483
DOI : 10.5916/jkosme.2009.33.4.476
A linear compressor used in a refrigerator has higher energy efficiency than a reciprocating compressor, but its vibration level is still severe than others. The vibration level of linear compressor at the frequency of 60Hz is dominant since it is the exciting frequency of a motor. In this paper, a simulation tool to predict the shell vibration of the linear compressor was developed. The shell and body parts in a compressor were assumed to be 3-dimensional rigid body having both translational and rotational motion, while the reciprocating piston part has only 1-dimensional translational motion. The flexible loop-pipe was modeled by in-house code of finite element method. To verify the developed tool, five cases of different loop-pipe shapes were examined experimentally. The results by the developed tool showed good agreements with those by experiments.
Performance and Safety Analysis of Marine Solid Oxide Fuel Cell and Gas Turbine Hybrid Power System (under Conditions of Turbine Cooling and Constant TIT)
Kim, Myoung-Hwan ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 4, 2009, Pages 484~496
DOI : 10.5916/jkosme.2009.33.4.484
The strengthened regulations for atmospheric emissions from ships like MARPOL Annex VI have caused a necessity of new, alternative power system in ships for the low pollutant emissions and the high energy efficiency. This paper attempts to investigate the configuration of SOFC/GT hybrid power system for LNG tanker taking into account the safety and to analyze the influence of design parameters on the system performance. The simulation results provide the basic data for the design and efficiency improvement of SOFC/GT hybrid system and indicate the guidelines for the safe system operation.
A Study on the Modal Parameter Identification of a Ship using Operational Modal Analysis
Kim, Byoung-Ook ; Jin, Bong-Man ; Kong, Young-Mo ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 4, 2009, Pages 497~501
DOI : 10.5916/jkosme.2009.33.4.497
When modal tests on the large structures and machinery are performed, it is in general difficult and inaccurate to use artificial excitation devices such as impact hammers, because of insufficient capacity of the device and different environmental conditions of the concerned structures. Therefore, the Operational Modal Analysis(OMA) technique, which is performed by measuring only vibration responses during the operation of the objective product, can be one alternative. In this paper, the way to identify natural frequencies, mode shapes and damping ratios of a ship by using the OMA during the sea trail is described.
Study on the Vibration of Diesel Engine Generator of Drill Ship
Jin, Bong-Man ; Park, Hyung-Sik ; Kong, Yong-Mo ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 4, 2009, Pages 502~508
DOI : 10.5916/jkosme.2009.33.4.502
To obtain high power, diesel engines continuously increase combustion pressure and mean effective pressure each cylinder, and the excitation sources and noisy sources are increased, too. Moreover, to reduce the costs, shipyards make hull structures weaker than before. As above reasons, it is more difficult to control the vibration phenomenon nowadays. In this study, it was investigated why diesel generator sets reached the vibration allowable limits during the FAT and heavy vibration phenomenon of diesel generator sets using ODS test during onboard tests. Also, it is found out the stiffness of deck and common bed using the test result of their structural impedance. To find out the vibratory characteristics of diesel generator sets, model tests were carried out. From the sensitivity analysis after above tests, it was selected points to be reinforced and studied troubleshooting to solve heavy vibration phenomenon of diesel generator sets.
A Study on Improving The Coefficient of Utilization of Material in Deep Drawing Process
Ha, Jong-Ho ; Kang, Hyung-Sun ; Baik, Ho-Hyun ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 4, 2009, Pages 509~516
DOI : 10.5916/jkosme.2009.33.4.509
This paper is the study on improving the coefficient of utilization of material in deep drawing process. Cylindrical cup drawing process is widely used in sheet metal forming process. The blank shape is one of the important things in sheet metal forming process. It is produced for the bridge of blank in a blanking process. The coefficient of utilization of material is much effected by this bridge of blank. This study offered a new process method to reduce the loss of material. The new blank shape offered and manufactured by new process method is investigated by a finite element method and the experiment. Then the wrinkling, the punch load, the thickness distribution is observed. This result is different from the result of circular blank process. And it is got that the Max strain, the wrinkle and the height of the wrinkle are effected by the holding force and the punch load. As a result, if the processing optimum condition is found, the loss of material will be reduced. It is necessary to research systematically about determining the optimum value of process variables.
Characteristics of Butt Welded AZ31 Magnesium Alloy with Laser Welding Conditions
Kim, Jong-Do ; Lee, Jung-Han ; Kim, Jang-Soo ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 4, 2009, Pages 517~523
DOI : 10.5916/jkosme.2009.33.4.517
Magnesium alloys have many advantages such as a low density, high strength/weight ratio and well recycle. And joining process is absolutely necessary to expand the field of application of magnesium alloy. The main problems of conventional process such as arc welding for magnesium alloy are the inflammability, a tendency toward crack formation and the appearance of porosity during solidification. Laser welding technology is a promising means for overcoming these difficulties. This study is related to the laser weldability of AZ31 magnesium alloy, an all-purpose wrought alloy with good strength and ductility. The effect of welding conditions on the weldability of butt joints was examined. Also, the mechanical properties of butt welded joints were investigated by tensile test and hardness test.
Analysis of Pressure Plate Behavior of a Clutch Including Thermal and Mechanical Material Properties
Hur, Man-Dae ; Lee, Sang-Uk ; Kim, Gug-Yong ; Kang, Sung-Su ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 4, 2009, Pages 524~532
DOI : 10.5916/jkosme.2009.33.4.524
In the mechanical clutches, the pressure plate is one of the important parts for transferring the power and reducing the vibration. Instead of gray and ductile irons, CGI(Compacted Graphite Cast Iron) is concerned to be the replacement recently. A thermo-mechanical coupled analysis was performed to investigate the behavior of the pressure plate for manual clutches. Thermal and mechanical properties of three kinds of cast irons were obtained from the mechanical experiments and referred other technical reports. The results of FEM analysis, were well match with the experimental ones. In this designated FEM method, temperature distribution, stress distribution and thermal deformation were successfully gained and these results will help to design the pressure plate which was made by cast irons including CGI.
Experimental Behaviors of the Constraint Effects A
Depending on Displacement at Various Measuring Positions near Crack Front for STS 316L CT Specimen
Han, Min-Su ; Jang, Seok-Ki ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 4, 2009, Pages 533~538
DOI : 10.5916/jkosme.2009.33.4.533
The magnitude of constraint effect
values on the non-linear elastic plastic fracture toughness was experimentally estimated by using displacement at various measuring positions near crack tip. Constraint effect
value was dependent on specimen configuration and on the measured displacement near crack front. The crack tip opening displacement in the vicinity of the crack tip front should be estimated within plastic region when appropriately constraint effect was calculated. It was found that the magnitude of constrain effect |
| is below 8.0 at the crack tip. But an appropriate location to measure the effective constraint effects
at the critical value of J that crack initiation is characterizable by is r = 2mm and
away from original crack tip, and the constraint effect |
| estimated is 5.3.
Evaluation of the Plastic Region Using Recrystallization Heat Treatment for Constraint Effect with STS 316L
Han, Min-Su ; Jang, Seok-Ki ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 4, 2009, Pages 539~544
DOI : 10.5916/jkosme.2009.33.4.539
The constraint effect
has to be evaluated within plastic region near crack tip front using opening displacement. Plastic boundary and stress or strain conditions in the vicinity of the crack tip using recrystallization heat treatment was represented. It was found that the plastic deformation boundary by recrystallization heat treatment method was the true strain of
= 0.05mm/mm. With the estimation of constraint effects
, the region of proper displacement measurement point near crack tip was between 0mm and 1mm distance toward direction of crack propagation, and was between 1mm to 3mm distance toward direction of load line.
Numerical Analysis on Flow Characteristics of Air Starting Motor for Marine Medium-Speed Diesel Engine
Yang, Su-Young ; Kim, Tae-Hun ; Lee, Yeon-Won ; Doh, Deog-Hee ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 4, 2009, Pages 545~552
DOI : 10.5916/jkosme.2009.33.4.545
The marine medium-speed diesel engines are operated by two methods; one is the electric motors, and the other air starting motors. Even though air starting motor is dependent of the engine types and sizes, it has been widely used in this area due to its simplicity, convenience and reliability. However most of them are currently imported from overseas due to the lack of the cutting-edge technology in terms of design and manufacturing. Therefore, from the point of this view, the air starting motor needs to be produced by our own techniques. The purpose of this paper is to give the designing parameters in order to make a proper "Air Starting Motor" using CFD. The aerodynamic approaches were given to understand the internal flow characteristics of the air starting motor. In addition, we have carried out the effects of tip clearance. In the calculations the tip clearance of air starting motor has been varied between 0% and 5.7% of blade span.
Development of Cleaning Module and Operating System of Underwater Robot for Ship Hull Cleaning
Choi, Hyeung-Sik ; Kwon, Kyoung-Youb ; Chung, Koo-Rack ; Seo, Joo-No ; Kang, Hyung-Suk ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 4, 2009, Pages 553~561
DOI : 10.5916/jkosme.2009.33.4.553
This paper presents development of ROV-type underwater robot capable of cleaning ship hull in automatic mode. The purpose of developing this robot is for underwater cleaning to secure the safety of divers who inspect and clean the ship hull. The robot consists of the cleaning system with rotating brush mechanism, a car-like driving mechanism, inspection system using video, and overall control system for underwater communication and operation. In this paper, we present overall design process of the cleaning system and operating system and technical contents of the overall control system for the underwater cleaning robot.
A Development of Ultra-compact Passive Components Employing Periodic Ground Structure for Silicon RFIC
Yun, Young ; Kim, Se-Ho ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 4, 2009, Pages 562~568
DOI : 10.5916/jkosme.2009.33.4.562
In this paper, using the periodic ground structure (PGS), highly miniaturized branch-line coupler and impedance transformer were realized on Si radio frequency integrated circuit (RFIC). The branch-line couple exhibited good RF performance from 41.75 to 50 GHz, and its size was
, which is 37 % of conventional one. The impedance transformer exhibited good RF performance from 1 to 40GHz, and its size was
, which is 6.99 % of conventional one.
Information Retrieval System for Mobile Devices
Kim, Jae-Hoon ; Kim, Hyung-Chul ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 4, 2009, Pages 569~577
DOI : 10.5916/jkosme.2009.33.4.569
Mobile information retrieval is an evolving branch of information retrieval that is centered on mobile and ubiquitous environments. In general, mobile devices are characterized by lightweight, low power, small memory, small display, limited input/output, low bandwidth, and so on. Some of these characteristics make it impossible to apply general information retrieval to mobile environments without any modification. In order to relieve this problem, we design and implement an information retrieval system for mobile devices like wireless phones, PDA and handheld devices. We use document summarization techniques to alleviate the limitation of small display and user profiles to retrieve the most proper documents for each individual user for personalized search. Futhermore we use meta-search to lighten some burdens visiting several portal sites. In this paper, we have implemented and demonstrated the proposed mobile information retrieval system on the domain of travel and received good evaluation from users subjectively.
Flow Analysis of the Tube Type Marine Auto-Backwashing Fuel Oil Filter
Yang, Jang-Sik ; Kim, Bong-Hwan ; Park, Young-Bum ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 4, 2009, Pages 578~587
DOI : 10.5916/jkosme.2009.33.4.578
In this paper, the characteristics of incompressible flow in a tube type marine fuel oil filter have been investigated. Fluent program has been used to obtain the solutions for the problems of three-dimensional, turbulent fuel oil flow in a filtering system. The inlet flow field is assumed to be uniform. The velocity and pressure distributions were obtained using Darcy's law. The increase of inlet velocity for cleaning fuel oil may cause some problems like vibration of the filter element. It was also required to consider the distribution of cleaning velocity because the worst distribution of cleaning velocity may cause the local insufficient cleaning effect and furthermore the effective filtration area can be reduced. The simulated results show that the computer code can be successfully applied for simulation of the complex base oil flow through the porous media. This paper could be applied to the design of auto-backwashing filtering system as design factor.
A Study on the MPPT Algorithm for Buoy
Jo, Kwan-Jun ; Jung, Sung-Young ; Bae, Soo-Young ; Lee, Ji-Young ; Oh, Jin-Seok ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 4, 2009, Pages 588~594
DOI : 10.5916/jkosme.2009.33.4.588
The maximum power point operation point(MPPOP) of photovoltaic(PV) power generation systems changes with varying atmospheric conditions such as temperature, solar radiation. For achieving a high efficiency in PV system, it is very important for PV system to track the MPPOP correctly according to operation condition. Although the MPPT(maximum power point tracking) algorithm which applied P&O(Perturbation & Observation) or IncCnd(Incremental Conductance) algorithm tracks the MPPOP efficiently, its efficiency drops noticeably in case that the incidence angle of PV panel on buoy changes rapidly. To solve this problem, this paper proposes maximum power point searching and tracking algorithm(MPPST). The proposed algorithm set the specific area and measures the PV voltage at the same interval. The proposed algorithm have been obtained high efficiency than P&O algorithm through ocean experiment.
Characteristics of Storm Surge near the Korean Peninsula in 2006 - 2007
You, Sung-Hyup ; Lee, Woo-Jeong ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 4, 2009, Pages 595~602
DOI : 10.5916/jkosme.2009.33.4.595
In this study, a two-dimensional storm surges/tide prediction model called the Storm surges/Tide Operational Model (STORM) was applied as the operational forecast model of the Korea Meteorological Administration (KMA). The operational model results were verified for two years (2006-2007) using observed results from tidal stations. Comparisons of modeled and observed storm surges show that larger differences at the western coast of Korea than at the southern and eastern coasts. The averaged root mean square error between the modeled and observed storm surges height are 0.16 m and 0.10 m in 2006 and 2007, respectively.