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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 36, Issue 8 - Nov 2012
Volume 36, Issue 7 - Nov 2012
Volume 36, Issue 6 - Sep 2012
Volume 36, Issue 5 - Jul 2012
Volume 36, Issue 4 - May 2012
Volume 36, Issue 3 - May 2012
Volume 36, Issue 2 - Mar 2012
Volume 36, Issue 1 - Jan 2012
Selecting the target year
Computational Study on The Effect of Injection Nozzle Hole Exit Angle Variation on Injection Characteristics
Kim, Ju Youn ; Park, Kweon Ha ; Lee, Seung Ho ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 8, 2012, Pages 997~1002
DOI : 10.5916/jkosme.2012.36.8.997
Emission regulations have been strengthened step by step for marine engines. A noble measure is required both inside and outside of the combustion chamber. The combustion characteristics in cylinder have a very close relationship with the exhaust emission characteristics. Injection valve and nozzle hole geometry is an important factor for combustion. The study to improve the spray characteristics has concentrated on nozzle inlet geometry and nozzle hole diameter, but the exit geometry has not considered. In this study the nozzle exit angle variation was tested. The results show that the angle between
is more effective than the other cases.
Study on Design Factor and Design-code Development for Plate Type Heat Exchangers
Ko, Jea-Hyun ; Park, Kweon-Ha ; Song, Young-Ho ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 8, 2012, Pages 1003~1009
DOI : 10.5916/jkosme.2012.36.8.1003
Heat exchanger has been widely used in the industry which needs energy transport, and the application of the plate type heat exchanger having high efficiency has been greatly increased. In this study main design parameters are analyzed and new equations are induced. The induced formulation was compared with a commercial program in order to design an optimal heat exchanger. The equations of heat transfer coefficient and pressure drop for Chevron angles are introduced as functions of Reynolds number. The program implemented the equations is tested with Chevron angle variation. The results show that the convective heat transfer coefficients take errors within 8% and the pressure drops have errors within 5% in the analysis conditions.
Analysis for DME FPSO Storage Tank and Experimental Study on the DME Evaporation Rate by Rolling Motion of Ship
Yun, Sangkook ; Cho, Wonjun ; Baek, Youngsoon ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 8, 2012, Pages 1010~1015
DOI : 10.5916/jkosme.2012.36.8.1010
DME(Dimethyl ether) is the one of the massive energy sources synthesized from natural gas. KOGAS has already developed the commercial-scale production plant of DME and has been doing to obtain overseas resources to meet the domestic needs. This paper presents the DME storage tank design criteria by stress and strain analysis, and the experimental study on the evaporation phenomena of DME by thermal intake and physical rolling movement of DME FPSO or cargo vessel, because the various moving motions along with heat intake cause the evaporation of low temperature liquid. The experimental result shows that the evaporation rate was increased with larger rolling degree and higher liquid level. The rolling motion leads to evaporate about 20% increase with 15 degree rolling based on the evaporation quantity without rolling.
A Study on Heat Transfer Characteristics for Cross Flow Heat Exchanger of Staggered Arrangement
Yoo, Jae-Hwan ; Yoon, Jun-Kyu ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 8, 2012, Pages 1016~1023
DOI : 10.5916/jkosme.2012.36.8.1016
Because heat exchanger consists of many circular tubes, the analysis of local heat transfer and pressure drop at the surrounding of circular tubes, performance and calculation of size, economics play important roles in design. In this study, This study conducted experiment and analysis in order to observe convective heat transfer coefficient LMTD (logarithm mean temperature difference) and pressure losses according to water temperature and air flow rate using a cross flow heat exchanger of staggered arrangement. This heat exchanger was composed of staggered arrangement for five rows and seven columns of tube banks, and the condition of experiment and analysis are
of water temperature and
of air flow rate. As a result of it, since air density decreases as water temperature and flow rate increases, Reynolds number decreases with characteristics of low flow velocity but mean heat transfer coefficient increases with air flow rate increase, heat transfer performance has been improved and pressure losses decreased. And since heat transfer rate shows about 8~12% and pressure drop around 0.01~7.5% error as the analysis result, the feasibility of this study could be evaluated.
Analytical Study on the Temperature and Pressure Changes in DME FPSO Storage Tank with Liquid Filling level
Yun, Sangkook ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 8, 2012, Pages 1024~1029
DOI : 10.5916/jkosme.2012.36.8.1024
As DME (Dimethyl ether) is the one of the future possible massive energy sources synthesized from natural gas, KOGAS has been doing to obtain overseas resources to meet the domestic needs. and tried to build new DME FPSO ship. This paper presents that it can help for the DME storage tank designers and storage management engineers doing proper work by understood the evaporation phenomena and pressure change of DME by thermal intake in storage tank. The experimental result shows that the evaporation rate and pressure are increased with higher liquid filling level. The proper DME liquid filling level in tank is obtained as lower than full 98% volume of tank in case of storing longer than a day, because the pressure is increased rapidly with full 98% filled level of storage tank.
CFD Performance Analysis and Design of a 8kW Class Radial Inflow Turbine for Ocean Thermal Energy Conversion Using a Working Fluid of Ammonia
Mo, Jang-Oh ; Cha, Sang-Won ; Kim, You-Taek ; Lim, Tae-Woo ; Lee, Young-Ho ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 8, 2012, Pages 1030~1035
DOI : 10.5916/jkosme.2012.36.8.1030
In this research, we analysed design and CFD analysis of an inflow radial turbine for OTEC with an output power of 8kW using an working fluid of ammonia. The inflow radial turbine consists of scroll casing, vain nozzle with 18 blade numbers and rotor blade with 13 blade numbers. Mass flow rate, and inlet temperature are 0.5kg/s and
respectively, and variable rotational speeds were applied between 12,000 and 36,000 with 3,000 rpm intervals. As the results according to the rotational speeds, the designed speed is 24,000 rpm where maximum efficiency exists. The maximum efficiency and output power are 88.66% and 8.52kW, respectively. Through this study, we expect that the analysed results will be used as the design material for the composition of the turbine optimal design parameters corresponding to the target output power under various working material conditions.
Exergy Analysis of R744 OTEC Power Cycle with Operation Parameters
Yoon, Jung-In ; Son, Chang-Hyo ; Baek, Seung-Moon ; Kim, Hyeon-Ju ; Lee, Ho-Saeng ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 8, 2012, Pages 1036~1042
DOI : 10.5916/jkosme.2012.36.8.1036
This paper describes an analysis on exergy efficiency of R744 OTEC power system to optimize the design for the operating parameters of this system. The operating parameters considered in this study include subcooling and superheating degree, evaporation and condensation temperature, and turbine and pump efficiency, respectively. The main results are summarized as follows : As the evaporation temperature, superheating degree, and turbine and pump efficiency of R744 OTEC power system increases, the exergy efficiency of this system increases, respectively. But condensation temperature and subcooling degree of R744 OTEC power system increases, the exergy efficiency of this system decreases, respectively. The effect of evaporation temperature and pump efficiency on R744 OTEC power system is the largest and the lowest among operation parameters, respectively. Therefore, the refrigerant temperature in the evaporator must be closely to the surface seawater temperature to enhance the exergy efficiency of R744 OTEC power system.
Development of the Decelerator for Briquetting Machine with Low Vibration
Lee, Hyoung Woo ; Hur, Nam Soo ; Kim, In Hwan ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 8, 2012, Pages 1043~1049
DOI : 10.5916/jkosme.2012.36.8.1043
In order to develop the decelerator for briquetting machine which composed of multi-staged gears, shafts and bearings, static design of the decelerator has been carried out through the analysis of bending and face forces, including structural analysis, applied on those teeth in accordance with AGMA(American Gear Manufacturers Association) standard. And also, dynamic design has been carried out with considering of vibratory forces caused by unbalance mass and transmitting error of gear. On the results of vibration analysis, it has been confirmed that there is not any critical speed within its operating range.
Performance Analysis of Hybrid SOFC/Uncooled GT System for Marine Power Applications
Kim, Myoung-Hwan ; Kil, Byung-Lea ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 8, 2012, Pages 1050~1060
DOI : 10.5916/jkosme.2012.36.8.1050
As an approach to high-efficiency of SOFC system, SOFC/GT Hybrid system is effective. However, if the output size of the system belongs to the marine class of dozens MWs, the introduction of the cooling system of GT system, which is used as sub-system, makes its related devices complicated and also makes its control difficult. Accordingly, for the marine use, SOFC/GT (non-cooling)Hybrid system looks more suitable than SOFC/GT(cooling)Hybrid system. This study established the SOFC/GT (non-cooling)Hybrid system, and examined the operating temperature & current density of the stack for the system, pressure ratio of the gas turbine, the influence of TIT(Turbine Inlet Temperature) on system performance, etc. through the simulation process. Through this research process, this study was able to confirm that electrical efficiency rises in spite of the increase in the required power for the air compressor, and there exists a limited range of temperatures for operation in TIT.
Weldability of STS316L for LNG Carrier by Fiber Laser
Kim, Jong-Do ; Lee, Jae-Beom ; Lee, Chang-Je ; Song, Moo-Keun ; Nam, Gi-Jeong ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 8, 2012, Pages 1061~1068
DOI : 10.5916/jkosme.2012.36.8.1061
These days, world wide interest about global warming and environmental pollution and exhausting fossil fuel which have been main energy source in all around the world. So many country have tried to find out the solution by investing new & renewable and clean energy. Therefore LNG have been widely used as a substitution of fossil fuel and clean energy that emits less pollutant like SOx, NOx. Therefore LNG consumption has been quickly raised and LNG carriers have been getting larger for decades. In this study, high power fiber laser was used for welding of stainless steel for LNG carrier to increase its productivity. Used material was STS316L which has low carbon less than 0.03% and its thickness was 8 mm. We carried out bead, lap and butt welding by using the fiber laser which has maximum power up to 5kW. As a result, we could find out that lap and butt joint was possible at welding speed of 2.0m/min and 3.0m/min respectively.
Characteristics of Fiber Laser Welding on STS304L for GTT MARK III Membrane
Kim, Jong-Do ; Lee, Chang-Je ; Song, Moo-Keun ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 8, 2012, Pages 1069~1075
DOI : 10.5916/jkosme.2012.36.8.1069
Laser is high density heat source, so it can make high speed welding with minimum heat input possible. Especially the high power fiber laser is recently commercialized and has high beam quality and the smallest system size compared with conventional laser due to it`s unique oscillating mechanism. Because of these advantages it`s thought that the most suitable heat source for LNG cargo tank welding precess which has to be conducted inside of ships. In this study fiber laser was used for welding of stainless steel for LNG carrier to applicate laser welding technique for shipbuilding industry. 1.2mmt STS304L of austenite stainless steel which apply to cargo tank was used for fiber laser welding. Butt and lap welding was conducted changing laser power, welding speed, then penetration characteristic was analyzed and optimal parameters for each materials. Consequently, we found that same or better mechanical properties were obtained in weld compared to base metal.
Comparison on Autogenous Weldability of Stainless Steel using High Energy Heat Source
Kim, Jong-Do ; Lee, Chang-Je ; Song, Moo-Keun ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 8, 2012, Pages 1076~1082
DOI : 10.5916/jkosme.2012.36.8.1076
Today the welding for LNG carrier is known to be possible using arc and plasma arc welding process. But because of the lower energy density, arc welding is inevitable to multi-pass welding for thick plate and has a limit of welding speed compared to laser which is high energy density heat source. When thick plate is welded, weld defect by multi-pass welding and heat-affected zone by high heat-input were formed. Therefore one-pass welding by key-hole has been considered to work out the problems. It is possible for Laser, electron beam, plasma process to do key-hole welding. Nowadays, plasma process has been used for welding membrane of cargo tank for LNG carrier instead of arc process. Recently, many studies have examined to apply laser process to welding of membrane. In this paper, weldability, microstructure and mechanical properties of stainless steel for LNG carrier welded by fiber laser were compared to those by plasma. As a result, although the laser welding has several times faster speed, similar properties and smaller weld and heat affected zone were obtained. Consequently, this study proves the superiority of fiber laser welding for LNG carrier.
Electrochmical Characteristics by Water Cavitation Peening of Cu Alloy
Kim, Seong-Jong ; Han, Min-Su ; Kim, Min-Sung ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 8, 2012, Pages 1083~1090
DOI : 10.5916/jkosme.2012.36.8.1083
Copper alloys are widely used for casting materials including ship`s propellers and pump impellers as they provide high corrosion resistance. In addition, the demand for these alloys is increasing with rapid growth of offshore structures and exploitation of various substitute energy sources. However, they require regular maintenance because of erosion and cavitation damages induced by exposure to marine environment at high speed flows for a long period of time. Water cavitation peening have received attention as one of surface modifications for durability improvement of the copper alloys. This is a environment friendly technology without influence of heat and easily applicable to casting materials. In this research, water cavitation peening was employed in distilled water for copper alloy castings as a function of time and evaluation of corrosion resistance was followed in seawater for the modified surface by using electrochemical methods. The result suggests that the water cavitation peening for 2 minutes was found to be the optimal peening parameter in terms of durability and corrosion resistance.
Flow Analysis over Moving Circular Cylinder Near the Wall at Moderate Reynolds Number
Kwag, Seung-Hyun ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 8, 2012, Pages 1091~1096
DOI : 10.5916/jkosme.2012.36.8.1091
The aerodynamic characteristics of circular cylinder in a channel are studied to make clear the flow feature by solving the Navier-Stokes equation based on the finite volume method with unstructured grids. Reviews are made on with the vorticity, velocity, dynamic pressure, residual and drag, where the Reynolds numbers are 50 and 100. The flows for
shows the vortex shedding in the wake, and the result is the same as the case of moving cylinder. The ground effect of flat bottom results in the growth of vortex, being generated in the upper side of the cylinder and elongated in the rear. As the cylinder approaches to wall, for example 0.6, the cylinder plays as a role of blockage to obstruct the flow between the cylinder and wall. The drag coefficients are compared with others` results to confirm the validity of the present numerical simulation.
A study on the Temperature Control of Insulated Open-End Water Vessel
Han, Seung-Hun ; Bae, Cherl-O ; Ahn, Byong-Won ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 8, 2012, Pages 1097~1103
DOI : 10.5916/jkosme.2012.36.8.1097
There are many fish farms being cultivated in the southwestern cost of South Korea. Because the farms cultivating use the basic method that inflow and circulate sea-water, slight negligence and bad design cause major negative impact on fish deaths. Also, the optimal temperature for each specie of fishes has already been proven to differ on each specie. Maintaining this environment, regardless of seasons, is very difficult and that requires research to develop. In this paper, basic characteristics of heat and mechanism of heat transfer are studied. Based on this, Open-end water vessel is designed and constructed using sandwich-insulation panels and simulated to store the heat in certain isolated space. This study confirmed that it is possible to keep constant temperature by this method, in large areas of water where it is insulated by heat insulator. and equipped with heater in Open-end water vessel where the other part is heated. The AC power controller maintains the constant temperature required and the temperature controller detects and displays the temperature by using the micro-processor.
Stabilizing Inverted Pendulum System Using Fuzzy Controller Based on State Variables Combination
Lee, Yun-Hyung ; Kim, Jong-Phil ; Jin, Gang-Gyoo ; So, Myung-Ok ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 8, 2012, Pages 1104~1110
DOI : 10.5916/jkosme.2012.36.8.1104
The inverted pendulum system is a common, interesting control problem that involves many basic elements of control theory. In the early, controls of stabilization for the inverted pendulum system were used classical methods like PD, PID controller. In recently, however, control methods based on modern and intelligent control theory are widely applied. The fuzzy logic controller which is often used in nonlinear control is a little too hard to design due to increasing fuzzy rules rapidly if the given system like inverted pendulum has many state variables. Also, in case the state variables are divided into two parts, two fuzzy controllers are needed in the control system. In this paper, the authors propose FCSC(Fuzzy Controller based on State variables Combination) that reorganized into two new signals depending on the physical meaning of the four state variables of the inverted pendulum system. The proposed method is applied to the inverted pendulum system and simulations are accomplished to illustrate the control performance.
Optical Wireless Remote Control Using Indoor LED Lightings
Sohn, Kyung-Rak ; Sohn, Chang-Woo ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 8, 2012, Pages 1111~1116
DOI : 10.5916/jkosme.2012.36.8.1111
At present, indoor optical wireless communications using LED lightings has been widely studied. The combination of this technology to the low voltage powerline grid installed in each home makes an efficient method for fulfilling the premise of broadband access for home networking. In this paper, white LEDs were used for both illumination and remote-control, so that information can be broadcast within a room for control the optical wireless systems. We implemented a model car to evaluate the performance of optical wireless remote-control. The requirement for levels of illumination suitable for communication were investigated and applied to design the test-bed. In spite of limitation of line-of-sight communications, it will open up new applications to the optical wireless remote control system in an electromagnetic interference region.
Implementation of Fuel Cell Simulator for Ship Using the Programmable Power Supply
Park, Do-Young ; Oh, Jin-Seok ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 8, 2012, Pages 1117~1122
DOI : 10.5916/jkosme.2012.36.8.1117
In order to study to apply the fuel cell, the study about the power system design and the load control is needed. However, to experiment the fuel cell need the auxiliary device and the complex control technology. For this reason the simulator is needed and such study is in progress actively. In this paper, the PEMFC (Polymer Electrolyte Membrane Fuel Cell) that is applied the vehicle, the small sized ship was simulated based on LabVIEW. The characteristic of fuel cell simulator was implemented based on a simulation data using the programmable power supply. The I-V characteristic according to various factors and the polarization curve of fuel cell were analysed.
Error-driven Noun-Connection Rule Extraction for Morphological Analysis
Lee, Kong Joo ; Lee, Songwook ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 8, 2012, Pages 1123~1128
DOI : 10.5916/jkosme.2012.36.8.1123
The goal of this research is to develop an error-driven noun-connection rules which is used for breaking complicate nouns in Korean morphology analysis module. We collected complicate nouns from Web sites, and analyzed them by CnuMa. Whenever we find errors from outputs of the analyzer, we write noun-connection rules to correct the errors. The noun-connection rules are devised by considering left/right contexts in compound nouns. The error-driven noun-connection rules are helpful in improving precision and recall of a Korean morphology analyzer, CnuMa by 2.8% and 10.8%, respectively.
NMF Based Music Transcription Using Feature Vector Database
Shin, Ok Keun ; Ryu, Da Hyun ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 8, 2012, Pages 1129~1135
DOI : 10.5916/jkosme.2012.36.8.1129
To employ NMF to transcribe music by extracting feature matrix and weight matrix at the same time, it is necessary to know in advance the dimension of the feature matrix, and to determine the pitch of each extracted feature vector. Another drawback of this approach is that it becomes more difficult to accurately extract the feature matrix as the number of pitches included in the target music increases. In this study, we prepare a feature matrix database, and apply the matrix to transcribe real music. Transcription experiments are conducted by applying the feature matrix to the music played on the same piano on which the feature matrix is extracted, as well as on the music played on another piano. These results are also compared to those of another experiment where the feature matrix and weight matrix are extracted simultaneously, without making use of the database. We could observe that the proposed method outperform the method in which the two matrices are extracted at the same time.
A Study on the Soft Ground Subsidence beneath the Jack-up Rig Working for Offshore Wind Turbine Installation
Lee, Eui-Chang ; Jang, Won-Yil ; Shin, Sung-Ryul ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 8, 2012, Pages 1136~1142
DOI : 10.5916/jkosme.2012.36.8.1136
With concern for new renewable energy sources rising, the offshore wind turbine energy market is growing. In order to install offshore wind turbines safely in a harsh environment, jack-up rigs need to be used. Recently, a WTIV(Wind Turbine Installation Vessel), which has a self-propelling system, was developed to replace traditional jack-up rigs. Since the jack-up rig works at 60 meters of depth in offshore and the seafloor is composed mostly of soft clay and sand, it is necessary to conduct a stability examination for ground subsidence before using it. This study conducts an improved numerical analysis of the effect of jack-up rig loading on the soft ground by using FLAC3D considering consolidation theory. This includes analyzing the amount of subsidence when applying different cases of surchargings. It can be concluded that the mid-loading method has an advantage as regards clay layers and the pre-loading method has an advantage as regards sand layers.
A study on Korean salvage competency analysis and development plan
Kim, Tae-Hyun ; Kang, Sin-Young ; Jung, Joo-Sung ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 8, 2012, Pages 1143~1150
DOI : 10.5916/jkosme.2012.36.8.1143
This paper reviewed the general definition and role of salvage duty, and performed competency analysis based on the present state of ROK Navy`s and Korean civilian`s salvage operation. Also, to enhance the national salvage ability, the salvage system of advanced maritime nations such as America, Great Britain were studied. Putting these information together, it is concluded that for the expansion and development of Korean salvage system, the nationally combined salvage assets must be utilized for civilian salvage operations and internationally recognized diving certification system should be introduced and joint organization of civilian-government-Navy should be established to enable the execution of such plans.
Basic Static Characteristics of a Closed and a Regeneration Cycles for the OTEC System
Cha, Sang-Won ; Kim, You-Taek ; Mo, Jang-Oh ; Lim, Tae-Woo ; Lee, Young-Ho ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 8, 2012, Pages 1151~1157
DOI : 10.5916/jkosme.2012.36.8.1151
Ocean Thermal Energy Conversion(OTEC) technology is one of the new and renewable energy that utilizes the natural temperature gradient that exists in the tropical ocean between warm surface water and the deep cold water, to generate electricity. The selection of working fluid and the OTEC cycle greatly influence the effect on the system operation, and it`s energy efficiency and impacts on the environment. Working fluids of the OTEC are ammonia, R22, R407C, and R410A. In this paper, we compared boiling pressure to optimize OTEC system at
. Also, this paper showed net-power and efficiency according to working fluids for closed cycle and regeneration cycle.