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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 32, Issue 8 - Nov 2008
Volume 32, Issue 7 - Nov 2008
Volume 32, Issue 6 - Sep 2008
Volume 32, Issue 5 - Jul 2008
Volume 32, Issue 4 - May 2008
Volume 32, Issue 3 - May 2008
Volume 32, Issue 2 - Mar 2008
Volume 32, Issue 1 - Jan 2008
Selecting the target year
A Study of Strength Analysis for Nacelle Cover of 2MW Wind Turbine System
Ko, Woo-Sik ; Lee, Hyoung-Woo ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 1, 2008, Pages 20~26
DOI : 10.5916/jkosme.2008.32.1.20
The nacelle cover and nosecone are made of composite materials, especially the stiffener is added in the nacelle cover in order to enhance it's stiffness. The nacelle cover consists of all three covers of left, right side cover and upper cover and each cover is connected with bolts. Also, the nacelle cover and nacelle frame are connected with bolts. The nacelle cover and nosecone have a important role to prevent the components of nacelle and rotor from external circumstances such as snow, rain and wind. Therefore, it is necessary to analyze and evaluate the strength and deformation for them in the design level. According to GL Wind Specifications, this paper shows the results that nacelle cover of 2MW wind turbine satisfy the strength and deformation throughout analysis using Patran/Nastran programs.
Effects of Biodiesel Fuel on Exhaust Emission Characteristics in Diesel Engine(Using Soybean Oil)
Lim, Jae-Keun ; Choi, Soon-Youl ; Cho, Sang-Gon ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 1, 2008, Pages 27~32
DOI : 10.5916/jkosme.2008.32.1.27
Recently, we have a lot of interest in alternative fuels to provide energy independence from oil producing country and to reduce exhaust emissions for air pollution prevention. Biodiesel, which can be generated from natural renewable sources such as new or used vegetable oils or animal fats, may be used as fuel in diesel engine of compression ignition engine. In this paper, the test results on specific fuel consumption and exhaust emissions of neat diesel oil and biodiesel blends(10 vol.% biodiesel and 20 vol.% biodiesel) were presented using four stroke, direct injection diesel engine, especially this biodisel was produced from soybean oil at our laboratory. This study showed that Soot and CO emission were decreased as the blending ratios of biodiesel to diesel oil increased, on the other hand NOx emission was slightly increased because of the oxygen content in biodiesel. Also, the biodiesel blends yielded slightly higher specific fuel consumption than that of diesel oil because of lower heating value of biodiesel.
A Study on the Measurement and Analysis of Bearing Reaction Forces of Marine Propulsion Shafting System using Strain-Gauge
Kim, Chul-Woo ; Lee, Yong-Jin ; Cho, Kwon-Hae ; Kim, Ue-Kan ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 1, 2008, Pages 33~41
DOI : 10.5916/jkosme.2008.32.1.33
Bearing damages by shaft misalignment have frequently been happened in marine ships. Specially. after stern tube bearing damage and failure for large crude oil carriers have been reported several times. However. the bearing reaction of the after stern tube bearing cannot be measured by jack-up test due to the hull structure condition. Therefore, when the jack-up test is used for the bearing reaction measurements, the bearing reaction for the after stern tube bearing obtained from the theoretical calculation method have to be used. In this paper, the shaft alignment on the large oil crude carrier is theoretically calculated and the differences between the calculated and actual installed bearing reaction values are compared. The bearing reactions for forward stern tube bearing and intermediate bearing are calculated by the simple formula using the strain gauge bending moments obtained from the measurements. Their reliability is confirmed by comparing the bearing reactions from jack-up test and the bearing reaction for after stern tube bearing is calculated by the same test. Also, the bearing reactions on the after stern tube bearing, forward stern tube bearing and intermediate shaft bearing under all operating conditions are calculated by using the bending moments obtained from the measurements and it is confirmed that the differences of the bearing reaction for all operating conditions are caused from hull deflection. The results of this study should prove useful for the future projects of the alignment calculation including the hull deflection effectiveness.
The Diagnosis and Evaluation of Vibration and Noise in Vessel
Gu, Dong-Sik ; Lee, Jeong-Hwan ; Choi, Byeong-Keun ; Kim, Won-Cheol ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 1, 2008, Pages 42~49
DOI : 10.5916/jkosme.2008.32.1.42
Most of vessels are not evaluated for their vibration and noise effects to human body. The vibration and noise generated by engine and auxiliary machine in vessel is a negative element for seamen. Therefore, in this paper, the diagnosis and evaluation of vibration and noise from vessel is accomplished by a shipbuilding corporation. The vibration and noise transferred from engine room and auxiliary machine was measured during the steady-state operation, and the vibration and noise map of vessel was made. Also, in order to evaluate the ship environment for human, the diagnosis is carried out on the base of measurement results.
Condensation heat transfer characteristics of R-22 and R-407C in micro-fin tubes
Roh, Geon-Sang ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 1, 2008, Pages 50~56
DOI : 10.5916/jkosme.2008.32.1.50
Experimental results for forced convection condensation of Refrigerant-22 and ternary Refrigerant-407C(HFC-32/125/134a 23/25/52 wt%) which is being considered as a substitute R-22 inside a horizontal micro-fin tube are presented. The test section was horizontal double-tube counterflow condenser with a length 4,000 mm micro-fin tube, having 8.53 mm ID, 0.2 mm fin height and 60 fins. The range of parameters of mass velocity were varied from 102.1 to 301.0 kg/(m2.s) and inlet quality 1.0. At the given experimental conditions. the average heat transfer coefficients for R-407C were lower than that for R-22 at a micro-fin tube. Over the mass velocity range tested. the PF(penalty factor) for R-22, R-407C were lower than the increasing ratio of heat transfer area by fins, and the EF(enhancement factor) for R-22, R-407C were higher than the increasing ratio of heat transfer area by fins.
Numerical Study on the Thermophoretic Deposition Characteristics of Soot Particles for Wall Temperature of Burner and Surrounding Air Temperature in Combustion Duct
Choi, Jae-Hyuk ; Han, Won-Hui ; Yoon, Doo-Ho ; Yoon, Seok-Hun ; Chung, Suk-Ho ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 1, 2008, Pages 57~65
DOI : 10.5916/jkosme.2008.32.1.57
The characteristics of soot deposition on the cold wall in laminar diffusion flames have been numerically analyzed with a two-dimension with the FDS (Fire Dynamics Simulator). In particular, the effects of surrounding air temperature and wall temperature have been discussed. The fuel for the flame is an ethylene (
). The surrounding oxygen concentration is 35%. Surrounding air temperatures are 300K, 600K, 900K and 1200K. Wall temperatures are 300K, 600K and 1200K. The soot deposition length defined as the relative approach distance to the wall per a given axial distance is newly introduced as a parameter to evaluate the soot deposition tendency on the wall. The result shows that soot deposition length is increased with increasing the surrounding air temperatures and with decreasing the wall temperature. And the numerical results led to the conclusion that it is essential to consider the thermophoretic effect for understanding the soot deposition on the cold wall properly.
In-situ Performance Evaluation of a Ground Source Heat Pump for an Air Conditioning System
Park, Youn-Cheol ; Park, Seong-Koo ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 1, 2008, Pages 66~72
DOI : 10.5916/jkosme.2008.32.1.66
In this study, the ground source heat pump was installed at a research center in Jeju Island to verify the performance of the system and to give an information for a economic feasibility. The performance test was conducted until the heat storage tank temperature reached at
in the cooling operation, and until the storage temperature goes up to
in the heating mode. As results, the system performance shows that
for the cooling operation and
for heating operation. It is found that the underground is good heat source for the heat pump with
variation range. The ground source heat pump could be connected one of air conditioning system without any problem in system performance. Based on the economic analysis, the initial cost for the ground source heat pump will be compensated after 4 years operation. If the system runs 20 years, approximately 300 million Won will be saved when the air conditioning system adapt the ground source heat pump based on Life Cycle Cost analysis.
Comparison of Various Heat Exchanger Performances in order for Air Compressor Intercooler Application
Yoo, Sang-Hoon ; Park, Sang-Gu ; Yoon, Jeong-Pil ; Jeong, Ji-Hwan ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 1, 2008, Pages 73~81
DOI : 10.5916/jkosme.2008.32.1.73
Intercooling and aftercooling are required in order to operate air compressor, these are conducted through air-cooled or water-cooled heat exchangers. This study aims to find more suitable type of heat exchanger as a water-cooled intercooler of air compressor. Comparative performance evaluation among fin-tube heat exchanger and shell-and-tube (S&T) heat exchanger having various tubes such as circular tube, spiral tube, and internally finned tube was conducted. Thermal-hydraulic performance of each heat exchanger type is evaluated in terms of temperature drop and pressure drop. The comparisons show that shell-and-tube heat exchangers may have similar and larger heat transfer capacity to the fin-tube heat exchanger if tube diameter is reduced and multiple pass is adopted. For these cases, however, compressed air pressure drop in shell-and-tube heat exchanger become much larger than that in fin-tube heat exchanger.
Numerical Investigation of Flow-pattern and Flow-induced Noise for Two Staggered Circular Cylinders in Cross-flow by LBM
Kim, Jeong-Whan ; Oh, Sae-Kyung ; Kang, Ho-Keun ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 1, 2008, Pages 82~93
DOI : 10.5916/jkosme.2008.32.1.82
The flowfield behind two cylinders and flow-induced noise generated from the cylinders in various arrangement are numerically investigated based on the finite difference lattice Boltzmann model with 21 velocity bits. which is introduced a flexible specific heat
to simulate diatomic gases like air. In an isolated cylinder with two type of mesh. some flow parameters such as Strouhal number
and acoustic pressure
simulated from the solution are given and quantitatively compared with those provided the previous works. The effects of the center-to-center pitch ratio
in staggered circular cylinders as shown in Fig. 1 and angles of incidence
, respectively, are studied. Our analysis focuses on the small-scale instabilities of vortex shedding, which occurs in staggered arrangement. With the results of drag
coefficients and vorticity contours. the mechanisms of the interference phenomenon and its interaction with the two-dimensional vortical structures are present in the flowfields under
. The results show that we successively capture very small pressure fluctuations, with the same frequency of vortex shedding, much smaller than the whole pressure fluctuation around pairs of circular cylinders. The upstream cylinder behaves like an isolated single cylinder, while the downstream one experiences wake-induced flutter. It is expected that, therefore, the relative position of the downstream cylinder has significant effects on the flow-induce noise, hydrodynamic force and vortex shedding characteristics of the cylinders.
The Visualization of the Flowfield around Square Prism Having Fences Using the PIV
Ro, Ki-Deok ; Kim, Kwang-Seok ; Oh, Se-Kyung ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 1, 2008, Pages 94~99
DOI : 10.5916/jkosme.2008.32.1.94
The characteristics of the flowfield of a square prism having fences on the corner was investigated by the PIV. Strouhal numbers, velocity vectors and velocity profiles around the square prism were observed at various positions of the fences, and Reynolds number of
. As the results in case of the prism having fences the Strouhal numbers were all smaller than in case of the prototype prism. In case of the prism having vertical fences on the front corners the concentrated intensity of the vorticity was the strongest and the size of separated shear layer was the largest. While in case of the prism having vertical fences on the rear corners the concentrated intensity of the vorticity was the weakest and the size of separated shear layer was the smallest. Also in this case, the flow separated in front corner was reattached around the rear corner and made circulation.
Hydrodynamic Characteristics of a Small Bee in Hovering Flight
Ro, Ki-Deok ; Kim, Kwang-Seok ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 1, 2008, Pages 100~109
DOI : 10.5916/jkosme.2008.32.1.100
The three-dimensional flows in the Weis-Fogh mechanism are studied by flow visualization and numerical simulation by the vortex method. The vortex method. especially the vortex stick method, is employed to investigate the vortex structure in the wake of the two wings. The pressure is estimated by the Bernoulli equation, and the lift on the wing are also obtained. As the results the eddies near the leading edge of each wing in the fling stage take a convex shape because the eddies shed from both tips entrain the flows and the downwash in the rotating stage is deflected toward the outside because the outside tip vortex is stronger than the inside one. And the lift coefficient on the wings in this mechanism is almost independent of the Reynolds number.
A Study on the Flow Characteristics inside a Glove Valve for Ships
Bae, Ki-Hwa ; Park, Jea-Hyoun ; Kang, Sang-Mo ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 1, 2008, Pages 110~118
DOI : 10.5916/jkosme.2008.32.1.110
It is essential for the valid design of a marine flow-control valve to exactly know its flow characteristics. The present study has numerically investigated the flow characteristics inside a marine throttle-type globe valve using a kind of commercial CFD code, CFX10.0, with an adoption of the SST (Shear-Stress Transport) turbulence model. To validate the numerical approach, the flow coefficients are compared with the experimental ones. Results show that the globe valve is effective in the control of flow rate according to the opening ratio in case of the forward-direction flow, whereas it is effective in the flow shutoff in case of the reverse-direction flow. Around the inlet of the valve, a recirculation region is formed due to the blunt body shape, the turbulence intensity becomes strengthened and then an abrupt pressure loss occurs.
Numerical and Theoretical Study on the Fluid Flow in the Cooling System of a Marine Diesel Engine
Suh, Yong-Kweon ; Heo, Seong-Gyu ; Chung, Sung-Sik ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 1, 2008, Pages 119~130
DOI : 10.5916/jkosme.2008.32.1.119
Diesel engine is one of the most expensive and important components in a ship. Many researchers are interested in increasing the performance of diesel engines. Design of an optimum cooling system should also contribute to the enhancement of the performance as well as the efficiency of engines. In this study, we investigated the flow pattern within the cooling system of a marine diesel engine by using numerical simulation prior to the study of the heat-transfer problem. The engine cooling system is composed of five cooling units each unit containing a water-jacket and a cylinder head. Based on the calculated data, we also conducted theoretical analysis that can predict the flow-rate delivery in each of the five units.
Weldment Design of Supports for Cryogenic Storage Tank considering Insulation
Choi, Dong-Jun ; Oh, Jung-Taek ; Jung, Jae-Hyun ; Cho, Jong-Rae ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 1, 2008, Pages 131~136
DOI : 10.5916/jkosme.2008.32.1.131
The double-walled steel vessel with powder insulation in the space between the walls is used to minimize heat transfer by radiation and conduction in cryogenic storage tank. The vacuum required the insulation is much less extreme than with high-vacuum or multilayer insulations. The solid supports are used to bear the weight of the inner container. Thermal and structural analysis of the tank have been carried out to study the effect of vacuum and weldment geometry of the internal supports. Heat flux in wall is increased with increasing of thermal conductivity of perlite. Heat flux and stress of support is not affected by weldment geometry.
Finite element analysis for prediction of bead shape of Nd:YAG laser butt welding
Kim, Kwan-Woo ; Nam, Gi-Jeong ; Lee, Jae-Hoon ; Suh, Jeong ; Cho, Hae-Yong ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 1, 2008, Pages 137~146
DOI : 10.5916/jkosme.2008.32.1.137
Nd:YAG pulse laser welding of stainless steel plate was simulated to find welding condition by using commercial finite element code MARC. Due to geometric symmetry, a half model of AISI 304 stainless steel plate was considered and user subroutines were applied to boundary condition for the heat transfer. Material properties such as conductivity, specific heat, mass density and latent heat were given as a function of temperature. As results, Three dimensional heat source model for pulse laser beam conditions of butt welding has been designed by the comparison between the finite element analysis results and experimental data on AISI 304 stainless steel plate. Nd:YAG laser welding for AISI 304 stainless steel was successfully simulated and it should be useful to determine optimal welding condition.
A Study on the Fabrication of Variable Attenuator using a Diode
Jeon, Joong-Sung ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 1, 2008, Pages 147~152
DOI : 10.5916/jkosme.2008.32.1.147
This paper has been fabricated the two different type of variable attenuators using a characteristics of a 3 dB directional coupler and pin diodes. One was not analyzed using the conventional even-odd modes but used simple two-port techniques. The resulting scattering parameters described operation characteristics for the general case where the terminating impedances are equal and unequal. After analyzing resistor role of the
type fixed attenuator. this paper used a pin diode instead of a resistor. The variable attenuators were fabricated using pin diodes for current-controlled attenuation on the coupled ports of a 3 dB branch-line coupler and
type fixed attenuator. The realized variable attenuators have more than 33 dB attenuation ranges at 2.1 GHz. and the input and output reflection coefficients are less than -13 dB. These results could be applied to mobile communication systems. It can be varied gain of the power amplifier according to change a outdoor environmental temperature and improved linearity.
A Data Analysis and RMS Development for Fish-cage in Open Sea
Oh, Jin-Seok ; Kwak, Jun-Ho ; Jung, Sung-Jae ; Ham, Yeon-Jae ; Lee, Ji-Young ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 1, 2008, Pages 153~161
DOI : 10.5916/jkosme.2008.32.1.153
Recently, the research and development of the fish cage in open sea from domestic is active and it is almost complement with commercial scale test on 'seogwipo'. But domestic technology is not sufficient of management RMS(Remote Monitoring System) with advanced country, so it is difficult to maintenance and monitor fish cage in open sea. This paper introduces a fish cage environmental monitoring system for measuring pH, DO and temperature. A signal is treated with DAU(Data Acquisition Unit) by a wireless communication method and transfers data to host computer for data processing. These data are graphically shown on the monitor with LabVIEW program and logged on the data processing system in the form of file.
Electrical and thermal characteristics of PRAM with thickness of phase change thin film
Choi, Hong-Kyw ; Kim, Hong-Seung ; Lee, Seong-Hwan ; Jang, Nak-Won ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 1, 2008, Pages 162~168
DOI : 10.5916/jkosme.2008.32.1.162
In this paper, we analyzed the heat transfer phenomenon and the reset current variation of PRAM device with thickness of phase change material using the 3-D finite element analysis tool. From the simulation, Joule's heat was generated at the contact surface of phase change material and bottom electrode of PRAM. As the thickness of phase change material was decreased, the reset current was highly increased. In case thickness of phase change material thin film was
, heat increased through top electrode and reset current caused by phase transition highly increased. And as thermal conductivity of top electrode decreased, temperature of unit memory cell was increased.
Theoretical Analysis of Wave Energy Converter
Oh, Jin-Seok ; Komatsu, Toshimitsu ; Kim, Yun-Hyung ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 1, 2008, Pages 169~174
DOI : 10.5916/jkosme.2008.32.1.169
Floating devices, such as a cavity resonance device take advantage of both the water motion and the wave induced motions of the floating body itself. The wave energy converter is known commercially as the WAGB(Wave Activated Generator Buoy) and is used in some commercially available buoys to power navigation aids such as lights and horns. This wave energy converter consists of a circular floatation body which contains a vertical center pipe that has free communication with the sea. A theoretical analysis of this power generated by a pneumatic type wave energy converter is performed and the results obtained from the analysis are used for a real wave energy converter for buoy. This paper presents the analysis results and the design method for the WEC(Wave Energy Converter), and the associate results are application to the commercially available WEC for buoy. Maximum performance of WEC occurs at resonance with driving waves. The analysis of WEC is performed with LabVIEW program, and the design method of WEC for buoy is suggested in this paper.
Design of a New Flexible In-pipe Inspection Robot
Choi, Hyeung-Sik ; Kim, Dong-Ho ; Kim, Dong-Hyun ; Lee, Jong-Hoon ; Whang, Kwang-Il ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 1, 2008, Pages 175~183
DOI : 10.5916/jkosme.2008.32.1.175
In this paper, a new in-pipe inspection robot was developed for inspecting a large number of circular pipe insides of the sea plant, ships, and buildings. A new pressure generation system was devised to inspect circular pipes with different diameters and to move up and down slant or perpendicular slopes inside of the pipe. Also, a design method was analyzed to decide the capacity of driving motor for the robot if the mass and maximum velocity of the robot are identified. According to the design specification, a robot was developed and was tested to verify the performance of the pressure generation system. For tests, a control system was developed.
An Implementation of a Map Building Algorithm for Efficient Traveling of Mobile Robots
Kim, Jong-Hwa ; Kim, Jin-Kyu ; Lim, Jae-Kwon ; Han, Seong-Bong ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 1, 2008, Pages 184~191
DOI : 10.5916/jkosme.2008.32.1.184
In order for a mobile robot to move under unknown or uncertain environment, it must have an environmental information. In collecting environmental information, the mobile robot can use various sensors. In case of using ultrasonic sensors to collect an environmental information, it is able to comprise a low-cost environmental recognition system compared with using other sensors such as vision and laser range-finder. This paper proposes a map building algorithm which can collect environmental information using ultrasonic sensors. And also this paper suggests a traveling algorithm using environmental information which leads to the map building algorithm. In order to accomplish the proposed traveling algorithm, this paper additionally discusses a position revision algorithm.
An Optimal Traveling Algorithm Based on Map Building for Mobile Robots
Kim, Jong-Hwa ; Kim, Jin-Kyu ; Lim, Jae-Kwon ; Han, Seong-Bong ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 1, 2008, Pages 192~199
DOI : 10.5916/jkosme.2008.32.1.192
In order for a mobile robot to move under unknown or uncertain environment. it is very important to collect environmental information. This paper suggests a traveling algorithm which leads to the map building algorithm and the
algorithm under the assumption that environmental information should already be collected. In order to apply the proposed traveling algorithm to a real mobile robot. this paper additionally discusses a path amendment algorithm. For the purpose of verifying the proposed algorithms, several simulations are executed based on a UI host program-based simulation interface and an experiment is executed using a mobile robot under a real unknown environment.
Stability of Artificial Reefs Installed in Gangwon Coastal Waters of the East Sea (Sea of Japan)
Kim, Wan-Ki ; Lee, Ji-Hyun ; Kim, Dai-Kweon ; Jo, Q-Tae ; Ahn, Jung-Mi ; Gong, Yong-Geun ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 1, 2008, Pages 200~205
DOI : 10.5916/jkosme.2008.32.1.200
Stability and durability of the artificial reefs (ARs) installed for wildstock enhancement have been a key issue. We surveyed the stability of 4,044 artificial reefs installed at 5 sites (Gangeung, Donghae, Samcheok, Goseong. and Yangyang) along the Gangwon coast of the East Sea (Sea of Japan) through which 1 to 5 typhoons pass annually. The ARs surveyed were 7 types aging 1 to 4 years. The side scan sonar (SSS) and scuba diving surveys confirmed that the ARs stability was age and type-dependent. A total of 85.56% ARs remained safe. the rest 14.44% being influenced by physical parameters of the waters such as wave extremes mostly caused by typhoons. An interesting observation was that the AR were particulatly vulnerable to the wave extremes in the first year of installation, thereafter being less damageable. Representative damages of the ARs were capsized (0.20%). broken (5.79%), sunk (0.27%), and buried (8.18%). By type, dice reef was most stable. while semicircle branch reef was most vulnerable.