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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 27, Issue 7 - Nov 2003
Volume 27, Issue 6 - Sep 2003
Volume 27, Issue 5 - Jul 2003
Volume 27, Issue 4 - Jul 2003
Volume 27, Issue 3 - May 2003
Volume 27, Issue 2 - Mar 2003
Volume 27, Issue 1 - Jan 2003
Selecting the target year
Introduction of Electronically Controlled Engine (ME)
Journal of the Korean Society of Marine Engineering, volume 27, issue 3, 2003, Pages 331~338
Behavior of Materials in Cold Region Environments
;;;Piyush K. Dutta;;
Journal of the Korean Society of Marine Engineering, volume 27, issue 3, 2003, Pages 340~355
Evaluation Criteria and Measurement Methods Revised of Vibration on the Diesel Engines and Propulsion Shafting
Journal of the Korean Society of Marine Engineering, volume 27, issue 3, 2003, Pages 356~364
A Flowfield Calculation around Two Circular Cylinders in Various Arrangements by a Discrete Vortex Method
Journal of the Korean Society of Marine Engineering, volume 27, issue 3, 2003, Pages 365~372
The Flow patterns around two cylinders in various arrangements were studied by a discrete vortex method. The flow for the surface of each cylinder was represented by arranging bound vortices at adequate intervals. The viscous diffusion of fluid was represented by the random walk method. The vortex distributions. streaklines. timelines and velocity vectors around two cylinders were calculated for centre-to-centre pitch ratios of P/D=1.5 and 2.5, attack ang1es of
. and Reynolds number of Re= 1200. The results of simulation correspond to the photographs by flow visualization and the flow intereference between two cylinders in various arrangements were clearly visualized by a numerical simulation.
A Study for NOx Discharge Characteristics of Diesel Engines
Journal of the Korean Society of Marine Engineering, volume 27, issue 3, 2003, Pages 373~380
According to the NOx regulations of annex Vi to IMO MARPOL 73/78, all diesel engines with a power output of more than 130 kW should be delivered so as to comply with the IMO speed dependent NOx limit. It is inevitable to adopt this regulations for marine engines Therefore, most of diesel engines which are being currently built should be designed and tested in accordance with the NOx technical code In this study, NOx concentrations of 4 type engines were measured with portable NOx measuring system recommended by ISO-8178. As the results NOx concentrations of each engine by variation of engine speed and engine load were visualized Also these results can be utilized for the basic design and development of diesel engine for NOx reduction.
A Study of the Noise Reflection Effect of an Alternator in a 13-liter Turbo-intercooler Diesel Engine
Journal of the Korean Society of Marine Engineering, volume 27, issue 3, 2003, Pages 381~387
Engine noise consists of the noise radiated from an engine structure and noises from engine ancillaries such as a turbocharger fuel injection system, and alternator. The noise of these ancillaries might be incorrectly evaluated in the aspect of the noise contribution to engine noise because the noise reflection effect of their neighbor engine structure is easily ignored. Consequently, noise source identification should be misled. This study investigates the fact that the engine structure located around an alternator reflects alternator noise, and the reflected noise acts as another alternator noise source in a heavy-duty diesel engine. The result shows that the alternator noise can be correctly estimated in engine noise by properly including the noise reflection effect.
Characteristics Improvement of Hydraulic Servosystem by Using Generalized Minimum Variance Adaptive Control
Journal of the Korean Society of Marine Engineering, volume 27, issue 3, 2003, Pages 388~394
Hydraulic system is difficult to obtain a suitable performance due to the nonlinearity load pressure change and system parameter variation. The requirement of control a1gorithm has been complex in order to satisfy the performance. The adaptive control is a control method which is suggested to achieve the control object under the plant characteristics change. In spite of the case that plant characteristics and the degree of variation are difficult to grasp. the adaptive control could keep the characteristics of closed-loop system generally. In this study. a method of combined generalized minimum variance adaptive control (GMVAC) and output error feedback is proposed, in order to solve the problem of non-minimum phase of plant and the vibration and overshoot in initial response. The control performance according to the variation of characteristics of plant is evaluated by changing the supply pressure. The experimental results show the effectiveness of the proposed scheme.
A Study on the Quantitative Visualization of Rayleigh-Bernard Convection Using Thermochromic Liquid Crystal
Journal of the Korean Society of Marine Engineering, volume 27, issue 3, 2003, Pages 395~404
Quantitative data of the temperature and velocity were obtained simultaneously by using liquid crystal tracer. PIV(Particle Image Velocimety) based on a grey-level cross-correlation method was used for visualizing and analysis of the flow field. The temperature gradient was obtained by applying the color-image processing to a visualized image, and a neural-network a1gorithm was applied to the color-to-temperature calibration. This simultaneous measurement was applied to the Rayleigh-Bernard convection. This paper describes the method, and presents the quantitative visualization of Rayleigh-Bernard convection and the effect of aspect ratio and viscosity. Also the experimental results were compared with the numerical results.
Characteristics of Solenoid on the Shape for Electric Control Injector in Diesel Engine
Journal of the Korean Society of Marine Engineering, volume 27, issue 3, 2003, Pages 405~411
An electric control fuel injector of a diesel engine injection systems is very important apparatus for fuel economy and emission control. It's performance was influenced by hydraulic contro1 of valve and solenoid especially the solenoid was important factor for operation and control of injector. In this paper. we made solenoids of 4 type. which changed the shape of armature and core. and measured magnetic force according to input current, and analyzed characteristics of solenoid on the shape through the test results.
A Study on Stability Analysis of Hydraulic System Using High Speed On-Off Valves
Journal of the Korean Society of Marine Engineering, volume 27, issue 3, 2003, Pages 412~420
This study describes the merits of PWM control of hydraulic system using high speed on-off valves. Generally, Electro-hydraulic valves can be classified into two classification: valves which are controlled by analog signal and which are controlled by digital. The former includes hydraulic servo valves and proportional valves which require A/D converters as interface to digital computer and too costly and sensitive to oil contamination because of complexity in structures. The latter includes high speed on-off valves which do not require A/D converters because they are normally operated in a pulse width modulation(PWM) method, and are low in price and robust to oil contamination because of their simple structures. The objectives of this study is to analyze the limit cycle which regularly appear in the position control system using 2/2way high speed on-off valves and to give a criterion for the stability of this system. The nonlinear characteristics of PWM and cylinder friction of this system are described by harmonic linearization and the effects of parameter variations to the system stability are simulated.
Hysteretic Characteristics of Wells Turbine for Wave Energy Conversion
Tae-Hun Kim ; Yeon-Won Lee ; Yeong-Yeun Hwang ;
Journal of the Korean Society of Marine Engineering, volume 27, issue 3, 2003, Pages 421~428
The aerodynamic characteristics of the Wells turbine for wave energy conversion have been investigated by the numerical simulation to reproduce hysteretic behaviors. The pressure distributions on the suction surface of the blade were investigated to find out the cause of the hysteretic mechanism. The results have shown that the hysteretic behavior is associated with streamwise vertical flow appearing near the suction surface and become more obvious. as the tip clearance and solidity change. Also it has shown that such phenomena occur due to different behaviors of wakes in the accelerating and decelerating flow process. The CFD analysis shows a good agreement with experimental results.
A Study on the Gap Voltage and Machining Stability in Diesinking Electrical Discharge Machining
Journal of the Korean Society of Marine Engineering, volume 27, issue 3, 2003, Pages 429~436
The electrical discharge machining(EDM) with Si electrode instead of Gr or Cu electrode. made enormous effects on the surface. machining time, anti-caustic workpiece surface and so on In this paper. we experimented on the inter-role distance during discharge the electrical phenomenon of inter-pole, the distribution of discharge point. the distribution of off load time. etc., using Si electrode Cu electrode and Gr electrode under the same machining condition. As a result of a large quantity generated exclusive powders. the performance of the EDM using Si electrode. compared with EDM using others. is improved. We show that the quantities of those make far pole-gap discharge and discharge scatter under stable machining status possible.
Large Eddy Simulation of Turbulent Pipe Flow
Journal of the Korean Society of Marine Engineering, volume 27, issue 3, 2003, Pages 437~446
A large eddy simulation (LES) is performed for turbulent pipe flow. The simulation code is constructed by using a general coordinate system based on the physical contravariant velocity components. The effects of grid fineness which can be well prediction of turbulent behavior in near wall region is investigated. The subgrid scale turbulent models are applied and validated emphasis is placed on the flow details of turbulent pipe flow The calculated Reynolds number is 360 based on the wall shear velocity and the inlet pipe diameter. The predicted turbulent statistics are evaluated by comparing with the DNS data of turbulent pipe flow Performed by Eggels et al. The agreement of LES with DNS data is shown to be satisfactory. The proper grid fineness of the well prediction of turbulent pipe flow is suggested and the turbulent behavior is analyzed by depict the contour plot of fluctuating velocity components
A Study on the Mechanism of Crevice Corrosion for 430 Stainless Steel
Journal of the Korean Society of Marine Engineering, volume 27, issue 3, 2003, Pages 447~452
Crevice corrosion is localized form of corrosion usually associated with a stagnant solution on the micro-environmental level. Such stagnant micro environments tend to occur in crevices (shielded areas) such as those formed under gaskets washers insulation material. fastener heads. surface deposits. disbonded coatings. threads. lap joints and clamps. Crevice corrosion is initiated by changes in located electrochemical reaction within the crevice such as a) depletion of inhibitor in the crevice b) depletion of oxygen in the crevice c) a shift to acid conditions in the crevice and d) build-up of aggressive ion species (e.g chloride) in the crevice. In this study. the mechanism of crevice corrosion for Type 430 stainless steel is investigated undercondition that the size of specimen is
, in 1N
+ 0.05N NaCl solution. and the artificial crevice gap size of 3 x 0.2 x 15 mm. Crevice corrosion is measured under applied potential -300mV(SCE) to the external surface. The obtained result of this study showed that 1) the induced time for initiation of crevice is 750 seconds. 2) potential of the crevice was about from -320mV to -399mV. which is lower than that of external surface potential of -300mV It is considered that potential drop in the crevice is one of mechanisms for the crevice corrosion
The Effect of Heat Treatment on the Corrosion-Resistance for Ti-6Al-4V Alloy
Journal of the Korean Society of Marine Engineering, volume 27, issue 3, 2003, Pages 453~459
In this study, the effect of heat treatment to the electrochemical polarization resistance for the Ti-6Al-4V alloy was measured. The solution heat treatments were carried out at
, followed by aging heat treated
. The electrochemical polarization resistance behavior was measured by potentio-dynamic polarization in the 1N
+ 15ppm HF solution. The obtained results were as follows. 1. As solution heat temperature increased. the corrosion potential was increased, whereas passive current density and critical current density were decreased. 2. As aging heat temperature increased, the corrosion potential was almost constant, but passive current density was decreased 3. The results of composition test measured by EDS at grain boundary and near
precipitates indicated that S, Cl. and Si which originated from base metal were segregated at the grain boundaries Al and Ti which were the main alloying element in
were depleted at the
precipitated. The depletion of Al and Ti in
was caused to early breakdown of passive film.
Flow Patterns of Gas-Liquid Two-phase Flow under Microgravity
Journal of the Korean Society of Marine Engineering, volume 27, issue 3, 2003, Pages 460~465
Microgravity experiments were conducted to determine the effect of liquid and gas superficial velocities on flow behaviors. Flow behaviors observed under microgravity conditions can be classified into five flow patterns: bubble. Taylor bubble, slug, semi-annular and annular flows. Transition boundary between four flow patterns could be determined by drift-flux model. It was also found that the effect of gravity and pipe inclination on flow pattern transition was not significant in the inertia dominant region.