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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 39, Issue 10 - Dec 2015
Volume 39, Issue 9 - Nov 2015
Volume 39, Issue 8 - Oct 2015
Volume 39, Issue 7 - Sep 2015
Volume 39, Issue 6 - Jul 2015
Volume 39, Issue 5 - Jun 2015
Volume 39, Issue 4 - May 2015
Volume 39, Issue 3 - Mar 2015
Volume 39, Issue 2 - Feb 2015
Volume 39, Issue 1 - Jan 2015
Selecting the target year
Effect of EGR on power and exhaust emissions in diesel engine
Song, Kyu-keun ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 9, 2015, Pages 870~875
DOI : 10.5916/jkosme.2015.39.9.870
Diesel engines are widely used due to superior power and fuel consumption, however there are many challenges in exhaust gas management. Exhaust gas recirculation (EGR) is the most effective technique for reducing mono-nitrogen oxide (NOx) emissions in a diesel engine, in comparison with other catalytic technologies. In addition, the technology has a number of advantages in terms of economic efficiency and implementation. In this study, the effects on the power and exhaust characteristics of diesel engines equipped with EGR systems were investigated. It was found that as the EGR rate increased, horsepower expressed as IHP and BHP decreased. The net effect of the application of EGR was measured at various engine speeds. EGR technology caused decreases in BHP of around 9% during low engine speed and 3.5% during high engine speed. Additionally, NOx emissions reduced as the EGR rate increased, and increased as engine speed increased. However, smoke emissions increased as the EGR rate increased, and decreased as engine speed increased. The optimum operating conditions and ERG rate to simultaneously achieve minimum NOx and smoke emissions were investigate. It was found that as the EGR rate increased, optimal operating speed for minimal NOx and smoke also increased. Keywords: Diesel engine, Exhaust gas recirculation, Power perfomance, Emission characteristics, NOx, Smoke
Thermal analysis of LNG storage tank for LNG bunkering system
Yun, Sang-kook ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 9, 2015, Pages 876~880
DOI : 10.5916/jkosme.2015.39.9.876
In 2016, the IMO's new rules for an 80% reduction in NOx emissions in newly built ships will necessitate the use of LNG as a clean fuel. So far, the developed European countries have led the development of LNG bunkering ships and related facilities. An LNG bunkering system stores LNG in a horizontal or vertical IMO "C"-Type tank insulated with perlite powder, and a vacuum in the annular space between the double walls, like the cryogenic liquid nitrogen tank. Current storage tanks have high heat leakage, evaporating over 2.0% daily, and are difficult to build with the required vacuum. A more efficiently insulated storage tank could reduce the evaporation rate. This research carried out thermal analysis on a new effective insulation method that separates high vacuum in the annular space between two tanks with a solid insulation material, such as urethane foam, lining the outer vessel. This highly efficient insulation system obtained an evaporation rate of 0.03% per day under a
vacuum, and an evaporation rate of 0.11% at
. Even if the space loses its vacuum, the new insulation system showed a lower evaporation rate of 4.12% than the present perlite system of 4.9%. This newly developed tank can increase the efficiency of LNG storage tank and may help keep LNG bunkering systems safe.
Performance analysis of an organic Rankine cycle for ocean thermal energy conversion system according to the working fluid and the cycle
Kim, Jun-Seong ; Kim, Do-Yeop ; Kim, You-Taek ; Kang, Ho-Keun ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 9, 2015, Pages 881~889
DOI : 10.5916/jkosme.2015.39.9.881
Ocean thermal energy conversion is an organic Rankine cycle that generates power using the temperature difference between surface water and deep water. This study analyzes the thermodynamic efficiency of the cycle, which strongly depends on the working fluid and the cycle configuration. Cycles studied included the classical simple Rankine cycle, Rankine cycles with an open feedwater heater and an integrated regenerator, as well as the Kalina cycle. Nine kinds of simple refrigerants and three kinds of mixed refrigerants were investigated as the working fluids in this study. Pinch-point analysis that set a constant pinch-point temperature difference was applied in the performance analysis of the cycle. Results showed that thermodynamic efficiency was best when RE245fa2 was used as the working fluid with the simple Rankine cycle, the Rankine cycles with an open feedwater heater and an integrated regenerator, and when the mixing ratio of
was 0.9:0.1 in the Kalina cycle. If the Rankine cycles with an open feedwater heater, an integrated regenerator, and the Kalina cycle were used for ocean thermal energy conversion, efficiency increases could be expected to be approximately 2.0%, 1.0%, and 10.0%, respectively, compared to the simple Rankine cycle.
Performance comparison of refrigeration cycle using R134a with the vapor-liquid ejector
Yoon, Jung-In ; Kim, Chung-Lae ; Son, Chang-Hyo ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 9, 2015, Pages 890~894
DOI : 10.5916/jkosme.2015.39.9.890
Recently, research on high-efficiency refrigeration cycles that apply an ejector to basic cycles has progressed actively. The role of the ejector and the performance of refrigeration cycles are subordinate to ejector locations. In this study, the performance of three refrigeration cycles with different ejector locations is compared and analyzed. The results showed an increased COP in all cycles due to the application of the ejector, with the highest increase of 44% compared to a basic refrigeration cycle. The ejector refrigeration cycle proposed in this study presents the highest COP, 3.47. Moreover, the decrease in condensation capacity in Bergander's cycle, Xing's cycle, and our proposed ejector refrigeration cycle went up to 21%. In refrigeration cycles applying the ejector, the pressure ratio of the ejector, the vapor fraction of discharge, and compression ratio are important factors for COP enhancement. For this reason, detailed and accurate control of these is significant.
A study on the design of cycloidal pitch reducer for the 2MW-class wind turbine
Min, Young-Sil ; Lee, Hyoung-Woo ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 9, 2015, Pages 895~902
DOI : 10.5916/jkosme.2015.39.9.895
In this paper, finite element analysis of a cycloidal pitch reducer for a 2 MW-class wind turbine is reviewed. The system is composed of one cycloid set, one spur gear set, an input shaft, an output shaft, and a housing. The system was also evaluated for stability by analyzing spur gear strength according to ISO 6336. An analysis of the natural vibration characteristics of the 2 MW-class wind turbine cycloid pitch reducer was performed with attention to critical speed with input mass unbalance, output mass unbalance, spur gear transmission error, cycloid gear transmission error, and excitation frequency.
Fundamental research for the development of full spectral-atigue analysis software to consider hydroelasticity effects
Park, Jun-Bum ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 9, 2015, Pages 903~910
DOI : 10.5916/jkosme.2015.39.9.903
The purpose of this research is to develop a full-spectral fatigue analysis program, based on rigid-body ship motion analysis, in order to perform a full-spectral fatigue analysis that considers hydroelasticity effects. To gain credibility, fatigue analysis results of two ship types, performed by the developed program, were compared with those of a classification society, and it was found that both are identical. Full-spectral fatigue analysis considering hydroelasticity effects would be developed in further studies by including flexible-body ship motion analysis results and by supplementing the developed program with a wide-band fatigue damage model.
Effect of fuel injection timing and pressure on the combustion and spray behavior characteristics of diesel fuel for naval vessel
Lee, Hyung-min ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 9, 2015, Pages 911~917
DOI : 10.5916/jkosme.2015.39.9.911
The objective of this work focuses on the analysis of injection rate and macroscopic spray behavior characteristics with injection pressures as well as combustion and exhaust emission characteristics with injection timing and injection pressure by using a common rail single-cylinder diesel engine. The injection rate was measured by applying the Bosch method, and macroscopic spray behavior characteristics were analyzed with a constant-volume vessel and a high-speed camera. In addition, combustion and emission characteristics were analyzed in a common-rail single-cylinder diesel engine with precise control of fuel injection timing and pressure. For injection pressures of 30MPa and 50MPa, the injection rate was higher at 50 MPa, and the spray development (penetration) was also higher in the same elapsed time. The peak in-cylinder pressure and rate of heat release showed a tendency to decline as injection timing was delayed, and the peak in-cylinder pressure and rate of heat release were slightly higher for higher injection pressures. Higher injection pressures also reduced the mean effective pressure, while the indicated mean effective pressure and torque increased as injection timing was delayed to TDC. Nitrogen oxides had a peak level at injection timings of
(50MPa); carbon monoxide emissions were reduced by delaying injection timing from
Estimation of explosion risk potential in fuel gas supply systems for LNG fuelled ships
Lee, Sangick ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 9, 2015, Pages 918~922
DOI : 10.5916/jkosme.2015.39.9.918
As international environmental regulations for pollutant and greenhouse gas emissions discharged from ships are being reinforced, it is drawing attention to use LNG as ship fuel. This paper compares the explosion risk potential in the LNG fuel gas supply systems of two types used in marine LNG fuelled vessels. By selecting 8500 TEU class container ships as target, LNG storage tank was designed and pressure conditions were assumed for the use of each fuel supply type. The leak hole sizes were divided into three categories, and the leak frequencies for each category were estimated. The sizes of the representative leak holes and release rates were estimated. The release rate and the leak frequency showed an inverse relationship. The pump type fuel gas supply system showed high leak frequency, and the pressure type fuel gas supply system showed high release rate. Computational fluid dynamics simulation was applied to perform a comparative analysis of the explosion risk potential of each fuel supply system.
A study on grid aspect ratio of fire dynamics simulator
Kim, Won Ouk ; Park, Woe-Chul ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 9, 2015, Pages 923~928
DOI : 10.5916/jkosme.2015.39.9.923
The FDS is one of the most used programs for fire analysis and needs an optimal grid selection for an accurate analysis. This study selected various grid aspect ratios (ARs) for selection of optimal grid and analyzed them with FDS v 6.1.2. A calculation time of 10 min. was used, which is enough to obtain the time average value of temperature changes. Temperature, visibility, and the time average value of mass balance are obtained from 200-600 s, which is a period of maintaining quasi-steady state. Two polyurethane fires of 1 [MW] and 2 [MW] in two enclosures of
were considered. Time variations of heat release rates, temperature, visibility, and mass balance were compared for ARs from 1-6. The heat release rates were accurate for all aspect ratios regardless of fire and enclosure sizes. The quasi-steady state temperature and visibility were well predicted for
. Temperature drop and skewness of mass conservation, however, increased with increasing aspect ratio. Therefore, careful investigation of the grid size is recommended in performance-based design when
, where temperature and visibility in early stage of a fire are important parameters. For accurate simulations of enclosure fires, grid sizes of 0.1~0.2 [m] and smaller in the vertical direction and
A study on the EMF strength standard in propulsion system on ship
Choi, Gi-Do ; Kim, Jong-Woo ; Cho, Hyung-Rae ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 9, 2015, Pages 929~934
DOI : 10.5916/jkosme.2015.39.9.929
Because of the recent rapid advances in the development of ships with a larger proportion of electrical and electronic equipment, The usable frequency spread spectrum on ships is global trend. Therefore, concerns have been raised regarding the possible hazardous health effects of electromagnetic fields radiating from electronic devices. Although studies and investments on electro-magnetic fields in terrestrial areas are being conducted, they are not applied to a ship. In this paper, we measured electromagnetic fields in ship propulsion systems, and we analyzed the measured values against Korean and international standards. While the measured results satisfied the Korean standard, the Italian standard was not met in the switchboard area. However, the measured values were close to meeting the Italian standard. Therefore, further studies should be conducted for performing a comparative analysis of data in order to specify a standard of electromagnetic fields in propulsion systems that can be applied in the construction of government infrastructures.
A sensorless speed control of brushless DC motor by using direct torque control
Yoon, Kyoung-Kuk ; Oh, Sae-Gin ; Kim, Deok-Ki ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 9, 2015, Pages 935~939
DOI : 10.5916/jkosme.2015.39.9.935
This paper describes sensorless speed control of brushless DC motors by using direct torque control. Direct torque control offers fast torque response, robust specification of parameter changes, and lower hardware and processing costs compared to vector-controlled drives. In this paper, the current error compensation method is applied to the sensorless speed control of a brushless DC motor. Through this control technique, the controlled stator voltage is applied to the brushless DC motor such that the error between the stator currents in the mathematical model and the actual motor can be forced to decay to zero as time proceeds, and therefore, the motor speed approaches the setting value. This paper discusses the composition of the controller, which can carry out robust speed control without any proportional-integral (PI) controllers. The simulation results show that the control system has good dynamic speed and load responses at wide ranges of speed.
A study on a dielectric heating system for amplifying the resonant gain using the capacitance of electrodes
Kim, Shin-Hyo ; Lee, Chang-Woo ; Bae, Han-Nah ; Cho, Dae-Kweon ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 9, 2015, Pages 940~946
DOI : 10.5916/jkosme.2015.39.9.940
In this paper, we study a method that amplifies the output gain of a high voltage pulse using 300 kHz or higher frequency. We conducted a study on a method for amplifying the output gain using the resonance between the capacitance components of the load and the parasitic components of the circuit, instead of the conservative method for amplifying the pulse-amplitude by raising the voltage of the power stage. In particular, the method simplifies the circuit configuration throughout the appliance of flyback-type topology instead of the bridge-type. There are advantages that prevent damage from overload and the heat in the output circuit through the hard switching by amplifying the gain of the output voltage applying to the load as given by the capacitance component of the output electrode to the output pulse waveform. This study proposed a method to enhance the spatial and electrical efficiency of the contact-type heating device through the dielectric heating method applied to the field of medical and industrial heating.
Extraction and analysis of doppler frequency of wind turbines and effect on radar signals
Jung, Joo-Ho ; Kang, Ki-Bong ; Kim, Min ; Kim, Jeung-Yuen ; Park, Sang-Hong ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 9, 2015, Pages 947~952
DOI : 10.5916/jkosme.2015.39.9.947
To supplement energy needs and take advantage of renewable energy sources, many wind farms are currently being built in mountainous areas under the supervision of the Korean government. However, operation of these wind farms can cause serious threats to national security due to Doppler modulation from the wind turbines causing interference with military radar operating in the vicinity. Therefore it is necessary to develop methods to analyze the Doppler frequency during the operation of wind turbines and the effect on radar signals. Based on modeling of the mountainous region, blockage analysis, turbine motion and the radar signals, this paper proposes a signal processing method to extract and analyze the Doppler frequency. Simulation results showed the change of Doppler frequency over time caused by the geometry of the mountainous area and the wind turbine.
Fabrication of smart alarm service system using a tiny flame detection sensor based on a Raspberry Pi
Lee, Young-Min ; Sohn, Kyung-Rak ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 9, 2015, Pages 953~958
DOI : 10.5916/jkosme.2015.39.9.953
Raspberry Pi is a credit card-sized computer with support for a large number of input and output peripherals. This makes it the perfect platform for interaction with many different devices and for usage in a wide range of applications. When combined with Wi-Fi, it can communicate remotely, therefore increasing its suitability for the construction of wireless sensor nodes. In addition, data processing and decision-making can be based on artificial intelligence, what is performed in developed testbed on the example of monitoring and determining the confidence of fire. In this paper, we demonstrated the usage of Raspberry Pi as a sensor web node for fire-safety monitoring in a building. When the UV-flame sensors detect a flame as thin as that of a candle, the Raspberry Pi sends a push-message to notify the assigned smartphone of the on-site situation through the GCM server. A mobile app was developed to provide a real-time video streaming service in order to determine a false alarm. If an emergency occurs, one can immediately call for help.
A study on indoor visible light communication localization based on manchester code using walsh code
Kim, Won-yeol ; Park, Sang-gug ; Cho, Woong-ho ; Noh, Duck-soo ; Seo, Dong-hoan ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 9, 2015, Pages 959~966
DOI : 10.5916/jkosme.2015.39.9.959
In this paper, we propose an indoor visible light communication(VLC) localization using Walsh code which can identify overlapped signals transmitted from the different LED sources as each of orthogonal signal at a receiver and using Manchester code which can eliminate the flicker of LED light and maintain a constant brightness. The proposed system can estimate the relative position of the receiver by using Lambertian radiation properties and trilateration method that are applied to the location information of fixed LED sources and the received signals from them. In order to verify the feasibility of the proposed system, we carried out the simulation in an indoor space with
installed LED lamps of 16. The simulation result shows that the proposed method achieves an average positioning error of 0.0536 m and a maximum positioning error of 0.2977 m.
A study of the hybrid electric drive generating mode in naval ships
Ryu, Seung-hyun ; Jung, Sung-young ; Oh, Jin-seok ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 9, 2015, Pages 967~972
DOI : 10.5916/jkosme.2015.39.9.967
Because of recent interests in energy conservation and prevention of environmental pollution, research related to these topics is increasing. The U.S. Navy has started to study the HED (hybrid electric drive) system in order to improve the COGAG propulsion system's fuel efficiency in AEGIS destroyers. (This ship's fuel consumption is 40% of the total fuel consumption of the U.S. Navy.) In addition, the Korean Navy is considering applications of the HED system in AEGIS destroyers. The purpose of this study is to analyze the U.S.A.'s HED system and to simulate its generating mode energy saving rate using LabVIEW. The results confirmed that the fuel savings are about 700 kg/h.
Development of PCS and an experiment for performance evaluation
Lee, Ha-jung ; Kim, Hae-jin ; Lee, Gye-gwang ; Jung, Hyo-seok ; Son, In-rak ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 9, 2015, Pages 973~980
DOI : 10.5916/jkosme.2015.39.9.973
With their wide geographical distribution, unconventional resources are continuously compared against conventional resources, but their development is expanding because TRRs (Technical Recoverable Resources) are similar to conventional resources. In particular, there is active development of unconventional gas resources such as shale gas, tight gas, CBM (coalbed methane) and gas hydrate. However, it is difficult to calculate the material properties of unconventional resources, especially the gas content, with current geophysical logging technology. Additionally, some overseas companies have monopolies on related equipment and materials. Therefore, this study developed a reservoir PCS (Pressure Core Sampler). It can collect core samples without gaseous loss by maintaining high pressure from the moment the core is sampled and record pressure and temperature in real time. Successful performance testing was also carried out for official verification of the manufactured PCS. The reservoir PCS will contribute to the acquisition of geophysical well logging data as well as accurate and reliable cores.
Countermeasures for reduction for CO
emission from training ship
Lee, Sang-Deuk ; Koh, Dae-Kwon ; Jung, Suk-Ho ;
Journal of the Korean Society of Marine Engineering, volume 39, issue 9, 2015, Pages 981~986
DOI : 10.5916/jkosme.2015.39.9.981
As the seriousness of global environment pollution is gaining increasing public attention, research into greenhouse gas emissions of ships is being carried out globally. At a domestic level, however, in a number of significant fields such research has not been conducted to date. This study examined countermeasures for the reduction of
emission in the fields of electronic control engines, trim optimization, propeller polishing, hull cleaning, and anti-fouling paint using an actual sea-going vessel. Selected countermeasures were applied during sea trials of the ship and the effect of specific fuel oil consumption analyzed. It was found that each countermeasure resulted in a decrease of fuel consumption of 1~5%. The energy efficiency operational indicator (EEOI) was calculated and found to also be improved by 1~5%. Further research into the EEOI of domestic shipping is planned to enhance conformance with international environmental regulations and improve global competitiveness.