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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
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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
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An Experimental Study on the Convection Heat Transfer of Al-Mg/water Micro Fluid in a Circular Tube with Swirl
Chang, Tae-Hyun ; Kim, Chiwon ; Kil, Sang-Cheol ; Lee, Chang-Hoan ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 7, 2012, Pages 869~875
DOI : 10.5916/jkosme.2012.36.7.869
In the past decades, extensive studies on convection heat transfer on internal flow have been conducted by using high specific surface area, by increasing heat transfer coefficient and swirl flow, and by improving the transport properties. In this study, we applied a tangential slot swirl generator to improve heat transfer in a horizontal circular copper tube. The Al-Mg particles (approximately
) were employed for this experimental work. The copper tube was heated uniformly by winding a heating coil with a resistance of 9 ohm per meter for heat transfer. Using Al-Mg particles, experiments were performed in the Reynolds number range of 5,000 to 13,130, with and without swirl. Experimental data transfers or comparisons between Nusselt numbers with and without swirl along the test tube and Reynolds numbers are presented. The Nusselt number is improved by increasing Reynolds numbers or swirl intensities along the test tube.
The First High Solar Concentrator System Performance Test in Korea
Chung, Kyung-Yul ; Kang, Sung-Won ; Kim, Yong-Sik ; Sim, Chang-Ho ; Jeong, Nam-Young ; Park, Chang-Dae ; Ryu, Keel-Soo ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 7, 2012, Pages 876~884
DOI : 10.5916/jkosme.2012.36.7.876
The worldwide CPV(Concentrated Photo Voltaic) market has been increased rapidly due to the increase in large-scale PV(Photo Voltaic) plants which are situated in sun-rich areas with either a Mediterranean or equatorial-type climate. CPV systems are arguably some of the most important devices in the production of electricity within regions with a sun-rich climate, particularly those which benefit from abundant direct solar irradiation. We have developed a 500X CPV module with rated power of 170Wp. The CPV module must satisfy the constraint of having a sensitive tracking accuracy due to the limited tolerance of the acceptance angle in intrinsic optical design. In this study, the module's acceptance angle used was designed with a tolerance angle of
in the secondary optics design. In general, non-concentrated module type 2-axis trackers have a tolerance angle larger than
due to standard silicon-type modules which are insensitive to the tracking accuracy of the sun. They have a tolerance angle of
, which fails to exert a significant influence on the performance of the module. This paper provides a study of an experimental variation of the efficiency of the CPV module in terms of its tracking accuracy. Also, the performance of the module is studied from the perspective of temperature and direct irradiation.
Combustion and Emission Characteristics of Diesel Engine by Mixing DME and Bunker Oil
Ryu, Younghyun ; Dan, Tomohisa ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 7, 2012, Pages 885~893
DOI : 10.5916/jkosme.2012.36.7.885
DME (Dimethyl ether) is regarded as one of the candidates of alternative fuels for diesel engine, because of its higher cetane number suitable for a compression ignition engine. Also, DME is a simple chemical structure, colorless gas that is easily liquefied and transported. On the other hand, Bunker oil (JIS C heavy oil) has long been used as a basic fuel in marine diesel engines and is the lowest grade fuel oil. In this study, the combustion and emission characteristics were measured experimentally in the direct injection type diesel engine operated with DME and Bunker oil mixed fuel. From our experimental results, it is induced that DME and Bunker oil blended fuel would be an effective fuel which can reduces the concentration of harmful matter in exhaust gases.
Water-jet Cleaning Motion of the In-Pipe Robot with Screw Drive Inside the Water Pipes
Kang, Hoon ; Oh, Jin-Seok ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 7, 2012, Pages 894~901
DOI : 10.5916/jkosme.2012.36.7.894
For more efficient use of the high pressure water-jet in rehabilitation of the water pipes, we have studied the water-jet cleaning motion of the in-pipe robot with screw drive. The mathematical models of the water-jet in the straight and the curved pipe (90 degrees elbow), representative features of the water mains, were designed to understand the water-jet motion and simulations have been performed. Furthermore the experiments has been conducted to validate the simulations by using the prototype in-pipe robot in the 3-D pipeline. The simulation results show that the water-jet motion in the straight pipe has a constant water-jet interval, whereas the motion in the curved pipe is changed by its position. By the comparison of the simulation and the experimental results, we have demonstrated that the simulations successfully estimate the water-jet motion inside the water pipes. Therefore in-pipe robot operators can predict a water-jet motion for a target water pipe through the simulation and flexibly make a proper water-jet motion by changing the robot configurations before a cleaning work.
Performance Improvement of a Micro Eco Cross-Flow Hydro Turbine
Kokubu, Kiyoshi ; Kanemoto, Toshiaki ; Son, Sung-Woo ; Choi, Young-Do ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 7, 2012, Pages 902~909
DOI : 10.5916/jkosme.2012.36.7.902
This study is aimed to develop a new type of micro cross-flow hydro turbine which has very simple structure and relatively high efficiency. Micro eco cross-flow hydro turbine (ECFT) is proposed to apply in the ranges of very low and middle specific speeds in order to extend the operational range of the turbine. In order to not only obtain a basic data for a new design method of ECFT but also improve the turbine efficiency, experiments and CFD analysis on the performance and internal flow characteristics of the turbine model are conducted. According to the present study results, anti-recirculation block (ARB) and relatively wide turbine width with high flow rate improve the turbine efficiency.
Distribution of CO Concentration in Two Tunnel Models Using CFD
Lee, Yong-Ho ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 7, 2012, Pages 910~918
DOI : 10.5916/jkosme.2012.36.7.910
Carbon monoxide (CO) is a primary air pollutant as an indicator of air quality released from motor vehicle combustion. A comparative study of the distributions of CO concentration with no heat source in two tunnel models open and closed at both end sides is simulated with a commercial CFD code. The tunnel models are used to investigate the CO concentration distributions at three Reynolds numbers, which are computed by the inlet velocities of 0.3, 0.6 and 1.0 m/s. For a better tunnel design, the CFD predictive approaches are available in qualitatively studying the distributions of CO concentration. In the case of the tunnel open at both end sides in sixty seconds, the total CO concentrations are approximately twenty eight percent higher than those in the closed case.
A Suggestion of Fuzzy Estimation Technique for Uncertainty Estimation of Linear Time Invariant System Based on Kalman Filter
Kim, Jong Hwa ; Ha, Yun Su ; Lim, Jae Kwon ; Seo, Soo Kyung ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 7, 2012, Pages 919~926
DOI : 10.5916/jkosme.2012.36.7.919
In order to control a LTI(Linear Time Invariant) system subjected to system noise and measurement noise, first of all, it is necessary to estimate the state of system with reliability. Kalman filtering technique has been widely used to estimate the state of the stochastic LTI system with stationary noise characteristics because of its estimation ability versus algorithm simplicity. However, it often fails to estimate the state of the LTI system of which system parameter uncertainty exists partly and/or input uncertainty exists. In this paper, a new estimation technique based on Kalman filter is suggested for stochastic LTI system under parameter uncertainty and/or input uncertainty. A fuzzy estimation algorithm against uncertainties is introduced so as to compensate the state estimate filtered by Kalman filter. In order to verify the state estimation performance of the suggested technique, several simulations are accomplished.
Performance Improvement of the Nonlinear Fuzzy PID Controller
Kim, Jong Hwa ; Lim, Jae Kwon ; Joo, Ha Na ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 7, 2012, Pages 927~934
DOI : 10.5916/jkosme.2012.36.7.927
This paper suggests a new fuzzy PID controller with variable parameters which improves the shortage of the fuzzy PID controller with fixed parameters suggested in . The derivation procedure follows the general design procedure of the fuzzy logic controller, while the resultant control law is the form of the conventional PID controller. Therefore, the suggested controller has two advantages. One is that it has only four fuzzy linguistic rules and analytical form of control laws so that the real-time control system can be implemented based on low-price microprocessors. The other is that the PID control action can always be achieved with time-varying PID controller gains only by adjusting the input and output scalers at each sampling time.
Analysis on Application of Flywheel Energy Storage System for offshore plants with Dynamic Positioning System
Jeong, Hyun-Woo ; Kim, Yoon-Sik ; Kim, Chul-Ho ; Choi, Sung-Hwan ; Yoon, Kyoung-Kuk ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 7, 2012, Pages 935~941
DOI : 10.5916/jkosme.2012.36.7.935
This paper describes a study of conventional electrical rig and simulated application of Flywheel Energy Storage system on the power system of the offshore plants with dynamic positioning system with the following aims: improve fuel consumption on engines, prevent blackout and mitigate voltage sags due to pulsed load and fault. Fuel consumption has been analyzed for the generators of the typical drilling rigs compared with the power plant with Flywheel Storage Unit which has an important aid in avoiding power interruption during DP (Dynamic Positioning) operation. The FES (Fly wheel Energy storage System) releases energy very quickly and efficiently to ensure continuity of the power supply to essential consumers such as auxiliary machinery and thrusters upon main power failure. It will run until the standby diesel generator can start and supply the electric power to the facilities to keep the vessel in correct position under DP operation. The proposed backup method to utilize the quick and large energy storage Flywheel system can be optimized in any power system design on offshore plant.
Electric Power System Design and Analysis for Drilling Rigs
Kim, Chul-Ho ; Kim, Yoon-Sik ; Jung, Hyun-Woo ; Ryu, Seung-Nam ; Yoon, Kyoung-Kuk ;
Journal of the Korean Society of Marine Engineering, volume 36, issue 7, 2012, Pages 942~947
DOI : 10.5916/jkosme.2012.36.7.942
As electricity has been used in ship's propulsion, it is necessary to increase the system voltage and current for the electrical distribution system. So it is required to improve the system safety and efficiency, the power stability, the efficiency of the generation through various analysis of ship's electric power system. In this paper, the electrical service reliability of the power distribution system of semi submersible drilling rigs has been analysed and discussed using ETAP.