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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
Characteristics of ignition and micro-explosion for droplets of water-in-fuel emulsion
Jeung, Incheol ; Lee, Kyung-Hwan ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 1, 2013, Pages 1~8
DOI : 10.5916/jkosme.2013.37.1.1
The water-in-fuel droplets were applied to investigate the effect of mixing ratio between water and decane, ambient temperature, droplet size and spacing between droplets on ignition and micro-explosion in a heated chamber with high temperature. The ignition temperature of droplet was found lower as the droplet size was increased and the contents of water was decreased. The life time of droplet, however, decreases as the contents of water increases due to the micro-explosion. The occurrence of micro-explosion also increases as the size of droplets and the ambient temperature increase. The flame spread speed gets faster as the contents of water and the number of suspender decreases.
Convective heat transfer characteristics of diamond nanofluid produced by matrix synthetic method
Son, Kwun ; Lee, Jung-Seok ; Park, Tae-Hee ; Park, Kweon-Ha ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 1, 2013, Pages 9~15
DOI : 10.5916/jkosme.2013.37.1.9
The effective use and management of energy resources has been issued to solve the global warming problem and petrolium price increase. To improve the energy efficiency of a heat exchanger, a new countermeasure is required and the heat transfer research of nano-fluids as a new working fluid is needed. This study was carried out with increasing the Reynolds number and the vol% of nano-fluids in the inlet temperature of
. As the result, the higher the entrance temperature is, the higher the convective heat transfer coefficient is.
Experimental investigation of heat transfer characteristics of alumina nanofluid
Kim, Yeong-Geun ; Jo, Sun-Hyeng ; Seong, Yong-Jin ; Chung, Han-Shik ; Jeong, Hyo-Min ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 1, 2013, Pages 16~21
DOI : 10.5916/jkosme.2013.37.1.16
Nanofluids are suspensions of metallic or nonmetallic nano powders in base liquid and can be employed to increase heat transfer rate in various applications. In this research the heat transfer characteristics has been experimented by alumina(50 nm)/water nano-fluids. Experimental results showed that the increasing the concentration of alumina nanofluids local and average heat transfer coefficient increased. The local heat transfer coefficient of 6 Wt% nanofluid was increased 37~46% than water at X/D=50~120. The average heat transfer coefficient of 6 Wt% nanofluid was rapidly increased than water at Reynolds number 1100~1300.
Numerical analysis of LNG vaporizer heat transfer characteristic in LNG fuel ship
Lee, Dae-Chul ; Afrianto, Handry ; Chung, Han-Shik ; Jeong, Hyo-Min ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 1, 2013, Pages 22~28
DOI : 10.5916/jkosme.2013.37.1.22
The heat transfer characteristics of LNG(Liquefied Natural Gas) vaporizer on the ship was performed by numerical simulation to get the optimum NG(Natural Gas) generating condition. The glycol-water was used for heating in LNG vaporizer, and the cooling water of main engine was used as heating souse for glycol-water. This cooling water temperature increases again after recirculating from the main engine, and then it can be used to heat the glycol-water. The numerical analysis results has good agreement with the experimental results by liquid nitrogen for validation. So CFD technique was used to simulate the heat transfer characteristics of LNG vaporizer on the ship. The numerical results show that the operation condition of LNG vaporizer shows NG temperature of
in the outlet of LNG vaporizer, and the mass flow rates of LNG and glycol-water were showed 0.111 kg/s and 1.805 kg/s, respectively.
A study on the titanium welding process according to the temperature characteristics of shielding methods
Chung, Han-Shik ; Jeong, Hyo-Min ; Lee, Dae-Chul ; Lee, Byeong-Yong ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 1, 2013, Pages 29~34
DOI : 10.5916/jkosme.2013.37.1.29
The welds tent to be weakened if it is exposed to the air during the welding process. In titanium welding with Gas Tungsten Arc Welding, inappropriate colors of the welds, such as purple/red, blue, yellow, gray, white and pink represents that it is contaminated by oxygen and nitrogen in the air. Shielding gases can be used to protect welds from the contamination. In addition, Weld metal and heat affected zone (HAZ) are also shielded from the air when it is cooled down to the room temperature. In this paper, appropriate shielding gases for the shape and form of Trailing Shielding Jig and torch shielding (
), after shielding (
), and back shielding (
) are studied.
Numerical study on the thermal behavior of a natural convection hybrid fin heat sink
Kim, Kyoung Joon ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 1, 2013, Pages 35~39
DOI : 10.5916/jkosme.2013.37.1.35
This paper reports numerical study results with respect to the thermal behavior of a natural convection cooled hybrid fin heat sink (HFH). The HFH consists of hybrid fins, hollow pin fins integrated with plate fins. The thermal performance of the HFH was numerically investigated by employing a commercial CFD software package and compared with that of the pin fin heat sink (PFH). Numerical study has found that array-based and mass-based heat transfer coefficients of the HFH are 12% and 37% greater than those of the PFH, respectively. Extended surface area and lighter weight may explain the better thermal performance of the HFH than the PFH.
Numerical analysis on heat transfer and pressure drop characteristics in a horizontal channel with various ribs
Kim, Ji-Hoon ; Heo, Joo-Nyoung ; Ahn, Sung-Hoo ; Lee, Doo-Ho ; Son, Young-Seok ; Shin, Jee-Young ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 1, 2013, Pages 40~46
DOI : 10.5916/jkosme.2013.37.1.40
Turbulent flow and heat transfer in a channel with a detached rib array have been simulated. The computations are based on the finite volume method with the SIMPLE algorithm. The forms of ribs considered in this study were rib with rectangular cross section, rib with groove, broken rib, and V-shaped rib. The ribs were deployed transverse or aligned
to the main direction of the flow. Local heat transfer coefficients were obtained at various Reynolds numbers within the turbulent flow regime. Area-averaged data were calculated in order to compare the overall performance of the tested ribbed surfaces and to evaluate the degree of heat transfer enhancement induced by the ribs with respect to the smooth channel. The highest heat transfer occurred for the rib with groove which was aligned
to the main flow direction. Performance factor was decreased with the increase of velocity, and it was found that the best performance factor was obtained in the low velocity region.
Predictions of the deteriorating performance for the marine diesel engines
Jung, Chan-Ho ; Rho, Beom-Seuk ; Lee, Ji-Woong ; Choi, Jae-Sung ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 1, 2013, Pages 47~52
DOI : 10.5916/jkosme.2013.37.1.47
The higher energy efficiency for ship and the lower pollution for global environment are required strictly. However the performance of marine diesel engine is gradually deteriorated with time. And also the operation condition is varied with sea conditions. Hence the optimization for operating condition of marine engines is needed for energy saving and environment kindly. In this paper, it was attempted to investigate the influence of aging for marine diesel engine. The deterioration of engine performance is assessed by the calculation results of the simulation program for two-stroke marine diesel engine developed by author which was reported before. And three parameters for deterioration of engine performance were considered such as lower efficiency of turbocharger by fouling, increase of blow-by gas due to wear of cylinder liner and getting worse of combustion by poor injection. By the results, it was shown that the influence of engine performance by aging was relatively not so small - 10.4 bar low in Pmax and 3.2% decrease in Pmi.
Comparison of combustion characteristics between esterified and non-esterified bio-diesel oil on CRDI diesel engine with turbocharger
Lee, Sang Deuk ; Jung, Suk Ho ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 1, 2013, Pages 53~58
DOI : 10.5916/jkosme.2013.37.1.53
In order to judge that non-esterified soybean oil could be used on diesel engine with electronic control of fuel injection system, The test of combustion performance using only gas oil, gas oil blended with esterified bio-diesel oil 5% and non-esterified soybean oil 5% were carried out. It is noticed that most performances of gas oil blended with esterified bio-diesel oil 5% and non-esterified 5% have similar characteristics but non-esterified bio-diesel oil 5% emitted smaller NOx, resulting from fuel NO.
Design and stress analysis of composite helical rotor and wind power tree
Ha, Min-Su ; Han, Kyoung-Tae ; Choi, Kyoung-Ho ; Park, Young-Chul ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 1, 2013, Pages 59~65
DOI : 10.5916/jkosme.2013.37.1.59
The objective of this paper is to analyze the structure of the wind power tree using a helical type wind turbine. The blades of a helical rotor is designed with a composite material. The structural analyses of a helical rotor have been implemented by finite element method. The structural analyses of the wind power tree which support four helical rotor, have been performed under a wind load, a rotational velocity of a rotor, and dead weight.
A study on forming analysis for the soft pipe bending process of thickness guarantee
Jung, Dong-Won ; Jeong, Ji-Hyun ; Cho, Jong-Rae ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 1, 2013, Pages 66~71
DOI : 10.5916/jkosme.2013.37.1.66
Soft bending pipe is widely used for freezing equipment and shipbuilding. These pipe have some problems that they cause occasionally outside wrinkle, crack, wall thinning phenomena. However, vending machines which have been made to solve the problems completely, are not yet. In this study, to settle these problems, we proved the effectiveness of the self-made mandrel by results of simulation as the basic for the development of precision high-quality vending machine ; presents the solution method of the wall thinning phenomena by analyzing circular deformation and damage of bending pipe.
The structural characteristics of ZnO thin films for TFT driver circuit
Son, Jihoon ; Kim, Sanghyun ; Kim, Hongseung ; Jang, Nakwon ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 1, 2013, Pages 72~77
DOI : 10.5916/jkosme.2013.37.1.72
The effect of sputtering condition on the structural properties of ZnO thin films grown by RF magnetron sputtering system was investigated for TFT driver circuit. ZnO thin films were grown with ZnO target varying RF power and working pressure. Structural properties were investigated by X-ray diffraction (XRD) and atomic force microscope (AFM). The ZnO thin films have sufficient crystallinity on the 100W RF power. But, the surface roughness of ZnO films was increased as increased RF power. As increased working pressure from 5 mTorr to 15 mTorr, a full width at half maximum (FWHM) of ZnO (002) peak was increased.
Design and CFD study of 360 W class wind turbine tree in accordance with environmental scenery
Ha, Min-Su ; Jung, Won-Hyuk ; Choi, Nak-Joon ; Park, Young-Chul ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 1, 2013, Pages 78~84
DOI : 10.5916/jkosme.2013.37.1.78
The objective of this paper is to develop 360 W class wind turbine tree using a helical type wind turbine. The performance of 100 W class helical wind turbine which finished the conceptual design has been forecast through the CFD analysis. After performed the analysis of one wind turbine performance, four wind turbine have been installed at the structure of a tree type and then the change of a output data has been verified through the CFD analysis. In this study, the CFD results of a helical wind turbine tree have been shown by a velocity and pressure distribution. The result could obtain more than rated power 360 W through the CFD analysis.
RCGA-based PID control of unstable processes concerned with the constraints
Lee, Yun-Hyung ; Yang, A-Young ; So, Myung-Ok ; Oh, Sea-Jun ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 1, 2013, Pages 85~90
DOI : 10.5916/jkosme.2013.37.1.85
PID control for unstable processes with time delay is not easy to apply because of unstability due to the poles existing on left-hand side in s-plane and the effect of time delay. In this paper, the authors consider the PID controller design technique in case of predefining overshoot or rising time by designer according to control environment. To deal with constraint problem like this, in this paper, the RCGA incorporating the penalty strategy is used. This is the method that if the RCGA violates given constraints, the defined penalty function is summed to the evaluation function depending on the severity and then the given constraint problem is converted to non-constraints optimization problem. The proposed method is applied to the unstable FOPTD(First Order Plus Time Delay) system and simulations are accomplished to illustrate the set-point tracking performance.
Study on the control of VCM and its application to the vibration isolator
Kim, Jin-Man ; Nam, Taek-Kun ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 1, 2013, Pages 91~98
DOI : 10.5916/jkosme.2013.37.1.91
The degradation of durability and increase of fatigue on the ship are mainly caused by vibration of the engine and rotating machineries. The damper to minimize the influence from vibration is usually attached between the machineries and its base. General damper applied on the vessel is passive damper which is designed to attenuate specified frequency signals, i.e, high frequency vibration signals. But it is hard to anticipate its performance for low frequency signals. In this research, active vibration isolator using VCM is developed to suppress wide band vibration signals. Routh-Huritz's stable condition, ultimate sensitivity method and parameter tuning are applied to derive PID parameters and 2 and 4 phase choppers are also adapted to drive VCM. Simulation and experiments are executed to confirm the effectiveness of the proposed control schemes.
A fully integrated downconverter MMIC for millimeter wave applications
Jeon, Jang-Hyeon ; Yun, Young ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 1, 2013, Pages 99~104
DOI : 10.5916/jkosme.2013.37.1.99
In this paper, we developed a fully integrated downconverter MMIC (monolithic microwave integrated circuit) including Lange coupler and output active balun for millimeter wave applications. Concretely,
/4 transmission line was added to Lange coupler for size reduction of RF/LO input, and mixed RF/LO signals were applied to gate of the FET of mixer. Active balun was used at output port for a coupling of out-of-phase IF output signals. According to measured results, the proposed downconverter MMIC showed good RF performances. For example, the downconverter MMIC showed an LO leakage power of -25 dBc at IF output port, and a RF-LO isolation of 18 dB. Therefore, off-chip components such as LO rejection filters were not required for a normal operation of the proposed downconverter MMIC. The proposed downconverter MMIC showed a conversion gain of 10.3 dB at RF frequency of 63 GHz. The size of the downconverter MMIC including all active and passive components was
An ultra-compact Wilkinson power divider MMIC with an improved isolation characteristic employing RCR design method
Yun, Young ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 1, 2013, Pages 105~113
DOI : 10.5916/jkosme.2013.37.1.105
In this work, using a
-type multiple coupled microstrip line structure (MCMLS) and RCR (Resistor Capacitor Resistor) structure, we fabricated ultra-compact and high isolation Wilkinson power divider on GaAs MMIC (Monolithic Microwave Integrated Circuit). The line length of the Wilkinson power divider was reduced to about
/46, and its size was 0.304 [
], which is 12.1 % of conventional one. Compared with conventional Wilkinson power divider, isolation characteristic of the proposed Wilkinson power divider was highly improved by using RCR insertion method. The proposed Wilkinson power divider showed good RF performances in C/X band.
A study on indoor navigation system using localization based on wireless communication
Kim, Jung-Ha ; Lee, Sung-Geun ; Kim, Jong-Su ; Kim, Jeong-Woo ; Seo, Dong-Hoan ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 1, 2013, Pages 114~120
DOI : 10.5916/jkosme.2013.37.1.114
Recently, navigation systems based on wireless communication have been applied to the internal structures such as building or ship. If a stable azimuth information is obtained, these systems can effectively guide the direction of the user's progress through the information and then can improve the performance of guidance. Since conventional method which has acquired an azimuth information using geomagnetic and acceleration sensor(azimuth sensor hereafter) is sensitive to the effects of the magnetic field, it has unstable error range according to the surrounding environment. In order to improve these problems, this paper presents a new relative azimuth estimation algorithm using the displacement of a mobile node and its rotation angle based on Wireless communication. For the performance assessment of the proposed algorithm, experiments using rotating arm are performed and the results are confirmed that the proposed system can estimate the relative azimuth without using additional sensors.
An improvement of cycloconverter output using phase shifting filter
Kim, Jong-Su ; Seo, Dong-Hoan ; Kim, Jeong-Woo ; Kim, Sung-Hwan ;
Journal of the Korean Society of Marine Engineering, volume 37, issue 1, 2013, Pages 121~126
DOI : 10.5916/jkosme.2013.37.1.121
Cycloconverter used as a power conversion device in the speed and torque control system of AC machines has the advantage of a simple control and a large torque at low speed. In addition, because a rectifier, a DC link, and an inverter are not installed, this system is simple and suitable for large power system. If a power conversion device, which is currently used as a propulsion motor of large vessel, is changed into cycloconverter, the system is simplified and then the installation costs can be significantly reduced. However, conventional cycloconverter has the increased harmonics because the power loss is large and the waveform of output voltage is distorted, due to the high-speed switching of power semiconductor devices. In order to improve these shortcomings, this paper describes a phase shifting filter which is composed of two inputs with different phases in the primary side and one output in the secondary one. As the voltage waveforms with two different phases are added and transformed into the secondary side, these outputs are close to sinusoidal waves. Thereby the voltage waveforms, which are applied to the propulsion motors, are improved and total harmonic distortions (THDs) are significantly reduced.