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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 37, Issue 8 - Nov 2013
Volume 37, Issue 7 - Nov 2013
Volume 37, Issue 6 - Sep 2013
Volume 37, Issue 5 - Jul 2013
Volume 37, Issue 4 - May 2013
Volume 37, Issue 3 - May 2013
Volume 37, Issue 2 - Mar 2013
Volume 37, Issue 1 - Jan 2013
Selecting the target year
Mass flow rate ratio analysis for optimal refrigerant charge of a R744 and R404A cascade refrigeration system
Oh, Hoo-Kyu ; Son, Chang-Hyo ; Jo, Hwan ; Jeon, Min-Ju ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 6, 2013, Pages 575~581
DOI : 10.5916/jkosme.2013.37.6.575
In this paper, the influences of several factors, such as subcooling, superheating degree, internal heat exchanger efficiency, and etc. to the optimal amount of refrigerant charge are investigated for the case of R744-R404A cascade refrigeration system. Refrigerants used in the cascade refrigeration system are R404A in high temperature cycle and R744 in the low temperature cycle. The main results are summarized as follows : The mass flow rate ratio decreases with increasing subcooling, superheating degree and internal heat exchanger efficiency in the high temperature cycle, and evaporating temperature and compression efficiency in the low temperature cycle. And the mass flow rate ratio decreases with decreasing temperature difference of cascade heat exchanger and evaporating, condensing temperature in the high temperature cycle, and subcooling, superheating degree and internal heat exchanger efficiency in the low temperature cycle.
Development of HIL simulator for performance validation of stack inlet gases temperature controller of marine solid oxide fuel cell system
Ahn, Jong-Woo ; Park, Sang-Kyun ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 6, 2013, Pages 582~588
DOI : 10.5916/jkosme.2013.37.6.582
Solid Oxide Fuel Cell (SOFC) has been focused as a promising power source, which can replace a diesel engine regarding as major source of air pollution by the ship, due to high efficiency and eco-friendly. High operating temperature of SOFC is enable to secure of high efficiency, use various fuels and no need of high priced catalyst, but it may damage to components of SOFC. Therefore temperature control system has to be designed and validated before employing the fuel cell system for securing high efficiency and reliability. In this paper, instead of using typical method to validate performance of the controller, which consumes high cost and time, performance validation system using Hardware-in-the-loop simulation was developed and validated performence of the designed temperature controller for SOFC system.
A study on the effect to yongrak phenomenon of submerged arc welding depending on the plasma cutting surface characteristics
Kim, Jeongtae ; Jeong, Hyomin ; Ji, Myoungkuk ; Chung, Hanshik ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 6, 2013, Pages 589~595
DOI : 10.5916/jkosme.2013.37.6.589
This paper was to study the effect to Yongrak phenomenon of I groove submerged arc welding depending on the plasma cutting surface characteristics, and how to reduce the causes and characteristics Yongrak phenomenon. Shipbuilding and marine structures is designed to use the thick plates and welded by high current to obtain deep penetration. Yongrak phenomenon has been occurred frequently depending on the quality of cutting surface and it makes degrade of the welding quality and modification of the welding. As a result, it was confirmed that I Groove plasma cutting characteristics get bevel form of 2 to 4 degrees to one side direction from the vertical position with Yongrak phenomenon. This is the main reason of Yongrak phenomenon in butt joint welding and 4 degree reverse bevel on the upper surface of base metal by submerged arc welding brought the effect of significant reduction of Yongrak phenomenon.
The research of wide band vibration energy harvester using ocean wave
Han, Ki-Bong ; Lee, Hyoung-Woo ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 6, 2013, Pages 596~602
DOI : 10.5916/jkosme.2013.37.6.596
In general, existed vibration energy harvester is optimum in electronic energy gleaned from vibration energy with fixed single frequency, because it is using resonance. But it is limit in electronic energy gleaned from ocean wave energy with variant frequency. This paper studied for width band vibration energy harvester that obtains electronic energy from ocean wave with infinite vibration energy in order to solve it. It is composed of buoy to occur resonance in the center frequency of ocean wave energy and the vibration system to occur resonance in the same frequency. As a result, existed vibration energy harvester using resonance maximized electronic energy conversion efficiency in single frequency, while proposed width band vibration energy harvester has merit that maximized electronic energy conversion efficiency in ocean wave with variant frequency.
Shape optimal design of a dust cover for ball joint of automotive steering system
Lee, Boo-Youn ; Kim, Ji-Ho ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 6, 2013, Pages 603~610
DOI : 10.5916/jkosme.2013.37.6.603
Finite element analysis is performed to evaluate stress and deformation of a wrinkle-type dust cover for the ball joints of tie rods of automotive steering system. Results of the analysis for assembly and operation condition show that sealing capability is good and the maximum stress on the body is smaller than the tensile strength. An optimal shape of the dust cover is obtained using the Taguchi method to reduce the maximum stress. The maximum stress of the optimal design under the operation condition is reduced by 22 per cent of that of the initial design. Results of the research show that performance evaluation and design of the dust covers can be effectively done using the proposed method.
Comparison of emission characteristics between fuel injection systems with echanical cam and electric control type on low speed 2 stroke diesel engine for ship propulsion
Lee, Sang Deuk ; Koh, Dae Kwon ; Jung, Suk Ho ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 6, 2013, Pages 611~616
DOI : 10.5916/jkosme.2013.37.6.611
Many researches have been carried out consistently for the green ship owing to its economic increasement, efficiency and convenience. One of them is an electronic controlled marine diesel engine. However, we are suffered from dissemination of above engine, due to its anxiety about safety and reliability. In order to solve these problems in this study, emission characteristics test of main propulsive two-stroke diesel engine, equipped both electronic control and cam drive fuel injection systems, has been performed and evaluated under the various load conditions. From the test results, we have confirmed that exhaust gas emission characteristics of the electronic control system is similar to the cam drive system in eco-mode operation, but NOx in emission mode has been decreased 100ppm or more in full load condition. HC emission from the electronic control system is decreased 10~20ppm at 50% load, and 35~40ppm at 25% load in comparison to cam drive system. In fuel consumption, it is considered that 7g/kWh is decreased than the value of cam drive system at 700bar of injection pressure, which is 200bar higher than cam drive system.
Numerical analysis of 2-DOF motions of an ocean floater with sloshing effects
Kim, HyunJong ; Choi, Yoon-Hwan ; Lee, Yeon-Won ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 6, 2013, Pages 617~622
DOI : 10.5916/jkosme.2013.37.6.617
The sloshing of liquid inside an ocean floater is caused by disturbances due to waves. For the analysis of sloshing impact within the floater and that of waves on the floater, the coupled analysis method is used. The Stokes
order non-linear wave theory equations were adapted for wave making. Furthermore, Navier-Stokes equation and Shear-Stress Transport (SST) turbulent model were used to Computational Fluid dynamics, where the ocean floater motions are considered the heave and the pitch motion. The results obtained confirms the mutual relationship between the rigid body motions and that of sloshing, where the sloshing behaviour within the floater is characterized by the wave effects on the floater.
Hydrodynamic evaluation for developing the inflatable kayak
Hah, Chong-Ku ; Lim, Lee-Young ; Ki, Jae-Seok ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 6, 2013, Pages 623~630
DOI : 10.5916/jkosme.2013.37.6.623
This study was to evaluate hydrodynamic performance evaluation between an abroad product, a developed inflatable kayak and new developed kayaks. In order to test, inclining and turning trial test were carried out in the Ocean engineering Basin. Also, resistance test was carried out using a reduced scale model in the circulating water channel. In conclusion, stability of KONA was evaluated was the most greatest, the coefficient of resistance and center of gravity from RD-FK-12 were considerable, and turning performance of RD-FK-11 was greater than this of KONA and RD-FK-12.
The effect of eccentricity between gear and housing in involute gear pump
Kim, Sung-Hoon ; Son, Hye-Min ; Lee, Jae-Cheon ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 6, 2013, Pages 631~637
DOI : 10.5916/jkosme.2013.37.6.631
The characteristics of involute gear pump with eccentric gap between gear tip and housing have been studied in terms of volumetric flow rate and/or flow efficiency. The analysis has been done with FLUENT/R-13 employing with k-e model for the turbulent flow under the given conditions of rotational velocity, gap distance and outlet pressure. The effect of parameters continues to be shown for the eccentric gear as same as for the concentric gear such that the volumetric flow rate (volumetric efficiency) increases as the increases of rotational velocity and decrease of gap distance and of outlet pressure. In the meantime, the shape of pressure build-up appears to be exponentially increase as gap distance decreases at upstream position. The pressure is rapidly developing in the upstream and remains almost constant thereafter in the downstream of circumferential flow path. This typical characteristics becomes more profound as eccentricity increases. The pump performance for the eccentric gear pump with minimum gap distance shows better than its concentric counterpart. However, it shows not for the concentric pump with minimum gap distance. Therefore, the gap reduction due to eccentricity may be positive for pump performance.
An experimental study on the improving noise characteristic of hydraulic power unit
Lee, Gi Chun ; Lee, Yong Bum ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 6, 2013, Pages 638~643
DOI : 10.5916/jkosme.2013.37.6.638
Nowadays, the hydraulic power unit (HPU) has been increased its working pressure and enlarged its capacity in order to improve the performance of the hydraulic system, but it produces noise leveled around 110dB(A) during operation. Recently, due to the reinforcement of industrial safety regulations and the requirement of improving work environment, a separated HPU room is installed at outside or underground of the building as to reduce the noise from HPU, but there are also problems of power loss owing its fluid friction of pipe system and of deficient accessibility during its failure accident. In this study, experiment is performed to improve the noise characteristics with installing a soundproof chamber to minimize the power loss and exclude effectively the high leveled noise, which is generated during the power conversion of HPU.
Implementation and field test for autonomous navigation of manta UUV
Ko, Sung-Hyub ; Kim, Dong-Hee ; Kim, Joon-Young ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 6, 2013, Pages 644~652
DOI : 10.5916/jkosme.2013.37.6.644
This paper describes the development and field experiments of Manta-type Unmanned Underwater Vehicle (UUV). Various simulations for Manta UUV are performed by using the nonlinear 6-DOF motion of equations. Through this simulation we verified the motion performances of Manta UUV. To acquire the blueprint of Manta UUV, it was designed with the simulation results. The Manta UUV uses a Doppler Velocity Log (DVL), gyrocompass, GPS, pressure sensor and other minor sensors, applied to measure the motion, position and path of Manta UUV. For its propulsion and changing a direction in the underwater, one vertical fin and four horizontal fins are installed at the hull of UUV. The Manta UUV system was verified with motion and autonomous navigation test at field.
A new sensorless speed control method for permanent magnet synchronous motor using direct torque control
Oh, Sae-Gin ; Kim, Jong-Su ; Kim, Sung-Hwan ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 6, 2013, Pages 653~658
DOI : 10.5916/jkosme.2013.37.6.653
This paper describes a new sensorless speed control method for permanent magnet synchronous motor(PMSM) using direct torque control(DTC). The direct torque control offers fast torque response, lesser hardware and processing costs as compared to vector controlled drives. In this paper the current error compensation technique is applied for sensorless speed control of synchronous motor. Through this method, the controlled stator voltage is applied to the synchronous motor so that the error between stator currents of the mathematical model and the actual motor can be forced to decay to zero as time proceeds and therefore, the motor speed approaches to the setting value. Especially, any PI controllers are not necessary in this control method. The simulation results indicate good speed and load responses from the low speed range to the high.