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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 28, Issue 8 - Nov 2004
Volume 28, Issue 7 - Nov 2004
Volume 28, Issue 6 - Sep 2004
Volume 28, Issue 5 - Jul 2004
Volume 28, Issue 4 - May 2004
Volume 28, Issue 3 - Mar 2004
Volume 28, Issue 2 - Jan 2004
Volume 28, Issue 1 - Jan 2004
Selecting the target year
Mistakes of Cooling Tower Performance Analysis
Journal of the Korean Society of Marine Engineering, volume 28, issue 3, 2004, Pages 397~404
A Trend of Infra Structure Establishment and Method of Performance Evaluation for Cooling Tower
Journal of the Korean Society of Marine Engineering, volume 28, issue 3, 2004, Pages 405~412
Experimental Study on the Flow around a Circular Cylinder with Tripping Wires
Journal of the Korean Society of Marine Engineering, volume 28, issue 3, 2004, Pages 413~422
The flow characteristic in the wake around a circular cylinder with tripping wires, which was set in constant distance, was experimentally investigated in the uniform flow, Re=2.92
. The measurement of velocity vector and pressure distribution are carried out various angles of tripping wires in the range of
interval. The results show that velocity profiles and pressure distributions are different with angles of tripping wires. The drag of the circular cylinder was decreased about 60% maximum when tripping wires' angle was
. The lowest reduction of the velocity and wake width was occurred by coanda effect when the angle was
, and the vortex shedding periodicity become rare at the same time.
Evaluation of turbulent SGS model for large eddy simulation of turbulent flow inside a sudden expansion cylindrical chamber
Journal of the Korean Society of Marine Engineering, volume 28, issue 3, 2004, Pages 423~433
A large eddy simulation (LES) is performed for turbulent flow in a combustion device. The combustion device is simplified as a cylindrical chamber with sudden expansion. A flame holder is attached inside a cylindrical chamber in order to promote turbulent mixing and to accommodate flame stability. The turbulent sub-grid scale models are applied and validated. Emphasis is placed on the evaluation of turbulent model for the LES of complex geometry. The simulation code is constructed by using a general coordinate system based on the physical contravariant velocity components. The calculated Reynolds number is 5000 based on the bulk velocity and the diameter of inlet pipe. The predicted turbulent statistics are evaluated by comparing with the LDV measurement data. The Smagorinsky model coefficients are estimated and the utility of dynamic SGS models are confirmed in the LES of complex geometry.
Influence of Bingham Characteristics for ER Fluid on Semi-Active Suspension System
Journal of the Korean Society of Marine Engineering, volume 28, issue 3, 2004, Pages 434~440
The electro-rheological fluids for semi-active suspension system are a class of colloidal dispersion which exhibit large reversible changes in their rheological behavior when they are subjected to external electrical fields. This paper presents Bingham properties of ER fluids subjected to temperature variations. In addition, an appropriate size of the ER damper for a passenger car is proposed to investigate the effects of Bingham characteristics on the damping performance. The filed-dependent damping forces are evaluated according to the temperature variation and sedimentation ratio.
A Study on the Velocity Distribution of Gas Molecules by the Molecular Dynamics Method
Journal of the Korean Society of Marine Engineering, volume 28, issue 3, 2004, Pages 441~450
The velocity distribution of gas molecules from the experimental results was confirmed as the same with the Maxwell-Boltzmann's theoretical results within the experimental error. This study is on the realization of the Maxwell-Boltzmann's velocity distribution of gas molecules by the molecular dynamics(MD) method. The Maxwell-Boltzmann's velocity distribution of gas molecules is extremely important to confirm the equilibrium state because the properties of a thermodynamic system shall be obtained from the system's equilibrium configuration in the MD method. This study is the first trial in the successive researches to calculate the properties of a thermodynamic system by the computer simulations. We confirmed that the maxwell-boltzmann's velocity distribution is developed in some transient time after starting a simulation and dependent on the size of a system. Also it is found that the velocity distribution has no relation with an initial configuration of gas molecules.
Heat Transfer Characteristics of Plastic Particle Slurry in a Circular tube Flow
Journal of the Korean Society of Marine Engineering, volume 28, issue 3, 2004, Pages 451~456
This present experimental study has dealt with the heat transfer characteristics of plastic particle slurry which flows in a circular tube. This type of slurry is suggested for heat transfer enhancement effect cause by random and vortex effect of plastic particle dispersed in water. As a result, the thermal boundary layer becomes thin so the heat transfer coefficient on the tube wall more increase compare to pure water flow. This experimental test section was composed with stainless pipe which has the length of 2000mm, inner pipe diameter of 14mm and outer pipe diameter of 60mm. The most effective and important parameter of this experiment is plastic packing factor(PPF). The focuses of these results are pressure drop and heat transfer coefficient. As results, the friction factor of plastic particle slurry becomes higher at laminar flow region than pure water because of buoyancy effect of plastic particle but the local heat transfer coefficient becomes higher.
A Study on the Characteristic of NOx Emissions by IMO Operating Modes in a Four Stroke Marine Power Generation Diesel Engine
Journal of the Korean Society of Marine Engineering, volume 28, issue 3, 2004, Pages 457~465
Environmental protection on the ocean has been interested and nowadays the International Maritime Organization(IMO) has advanced on the prevention of air pollution from ships. This study presents the performance and the emission characteristics of 4 stroke marine diesel engines for generation application in D2 cycle(IMO mode). The effects of important operating parameters, such as intake air pressure. intake air temperature and maximum combustion pressure on NOx emissions were also described. Emissions measurement and calculation are processed according to IMO Technical Code. The results show that the maximum combustion pressure by fuel injection timing control and intake air temperature has strong influence on NOx emission production. But NOx emission is not affected by intake air pressure and exhaust gas back pressure.
The Characteristics of a Transient Liquefied Butane Spray using PDPA and High Speed Camera
Journal of the Korean Society of Marine Engineering, volume 28, issue 3, 2004, Pages 466~474
The characteristics of liquefied butane spray are expected to be different from conventional diesel fuel spray, because a flash boiling spray is expected when the surround pressure is below the saturated vapor pressure of the butane(0.23MPa 98K). The axial velocities. radial velocities. and size distributions in butane sprays were measured with PDPA(Phase Doppler Particle Analyzer) system. Sprays were macroscopically observed by using the high speed camera in case that the surround pressure is 0.37MPa and 0.15MPa. respectively. Compared with the conventional spray. the reversed results were investigated when the surround pressure is below the saturated vapor pressure of the butane.
A Experimental Study on the Electronic Control Hysteresis Phenomenon of Lean Burn in Spark Ignition Engine
Journal of the Korean Society of Marine Engineering, volume 28, issue 3, 2004, Pages 475~481
Recently it is strongly required on lower fuel consumption. lower exhaust emission, higher engine performance. and social demands in a spark ignition gasoline engine. In this study. the experimental engine used at test. it has been modified the lean burn gasoline engine. and used the programmable engine management system, and connected the controller circuit which is designed for the engine control. At the parametric study of the engine experiment, it has been controlled with fuel injection, ignition timing. swirl mode, equivalence ratio engine dynamometer load and speed as the important factors governing the engine performance adaptively. It has been found the combustion characteristics to overcome the hysteresis phenomena between normal and lean air-fuel mixing ranges. by mean of the look-up table set up the mapping values. at the optimum conditions during the engine operation. As the result, it is found that the strength of the swirl flow with the variation of engine speed and load is effective on combustion characteristics to reduce the bandwidth of the hysteresis regions. The results show that mass fraction burned and heat release rate pattern with crank angle are reduced much rather, and brake specific fuel consumption is also reduced simultaneously.
A Study on the Coupled Torsional-Axial Vibration of Marine Propulsion Shafting System using the Energy Method
Jang, Min-Oh ; Kim, Ue-Kan ; Park, Yong-Nam ; Lee, Young-Jin ;
Journal of the Korean Society of Marine Engineering, volume 28, issue 3, 2004, Pages 482~492
Recently. the market trend for marine diesel engine has involved the lower running speeds. larger stroke/bore ratio and higher combustion pressure. Consequently, because of the flexible engine shafting system due to the larger mass. inertia and the more elasticity, the complicated coupled torsional-axial vibrations have occurred in the operating speed range. Also, the vibrations act as an excitation on the hull-structural vibration. To predict the vibration behavior with more accuracy and reliability. many studies have proposed the several kinds of method to calculate the stiffness matrix of crankshaft. However, most of these methods have a weak point to spend much time on three dimensional modeling and meshing work for crankshaft. Therefore. in this work. the stiffness matrix for the crankthrow is calculated using the energy method (Influence Coefficient Method, ICM) with the each mass having 6 degree of freedom. Its effectiveness is verified through the comparison with the stiffness matrix obtained by using the finite element method (FEM) and measured results for actual ships propulsion system.
A Study about Vortex Flow Characteristics on Delta Wing by Time-resolving PIV
Journal of the Korean Society of Marine Engineering, volume 28, issue 3, 2004, Pages 493~499
The dominant effect of the interaction between vortices, generated by the addition of the Leading Edge Extension(LEX) in front of the wing, was well observed in this experiment. In this study, systematic approach by PIV experimental method within a circulating water channel was adopted to study the fundamental characteristics of induced vertex generation, development and its breakdown appearing on a delta wing model with or without LEX in terms of four angles of attack(
) and six measuring sections(30%, 40%, 50%, 60%, 70%, 80%) of chord length. Distributions of time-averaged velocity vectors and vortices over the delta wing model were compared along the chord length direction. High-speed CCD camera which made it possible to acquire serial images is able to get the detailed information about the flow characteristics occurred on the delta wing. Especially quantitative comparison of the maximum vorticity featuring the induced pressure distribution were also conducted to clarity the significance of the LEX existence.
The heat transfer and pressure drop characteristics of
during supercritical region in a horizontal tube
Journal of the Korean Society of Marine Engineering, volume 28, issue 3, 2004, Pages 500~508
The heat transfer coefficients during gas cooling process of carbon dioxide in a horizontal tube were investigated. The experiments are conducted without oil in the refrigerant loop. The main components of the refrigerant loop are a receiver, a variable-speed pump, a mass flow meter, a pre-heater, and a gas cooler(test section). The water loop consists of a variable-speed pump, an isothermal tank, and a flow meter. The gas cooler is a counterflow heat exchanger by cooled water flowing in the annulus. The
flows in the horizontal stainless steel tube. which is 9.53mm in O.D. and 7.75mm in I.D. The gas cooler is 6 [m] in length. which is divided into 12 subsections, respectively. The experimental conditions considered in the study are following range of variables : refrigerant temperature is between 20 and
. mass fluxes ranged from 200 to 400kg/(
.s), average pressure varied from 7.5 to 10.0MPa. The main results were summarized as follows : The friction factors of
in the gas cooler show a relatively good agreement with those predicted by Blasius' correlation. The local heat transfer coefficient in the gas cooler has compared with most of correlations, which are the famous ones for forced convection heat transfer of turbulent flow. The results show that the local heat transfer coefficient of gas cooler agrees well with the correlation by Bringer-Smith except that at the region near pseudo critical temperature. while that at the near pseudo critical temperature is higher than the correlation.
A Quantitative Visualization of Mixed Convection in Parallel Plates Using PIV
Journal of the Korean Society of Marine Engineering, volume 28, issue 3, 2004, Pages 509~515
The PIV(Particle Image Velocimetry) with liquid crystal tracers is used for visualizing and analysis of the mixed convection in the parallel plates with the upper part cooled and the lower part heated. It is found that the flow pattern of mixed convection in the parallel plates can be classified into three patterns which was affected by Reynolds number. Also, the periodic nature is confirmed, and visualized in experiment.
Emission Characteristics of a Gasoline Engine Using Ethanol Blended Fuel
Journal of the Korean Society of Marine Engineering, volume 28, issue 3, 2004, Pages 516~521
In this paper, the effects of ethanol blended gasoline on emissions and their catalytic conversion efficiencies characteristics were investigated in gasoline engine with an electronic fuel injection. The results showed that the increase of ethanol concentration in the blended fuels brought the reduction of THC and
emissions from the gasoline engine. THC emissions were drastically reduced up to thirty percent. And brake specific fuel consumption was increased. but brake specific energy consumption was similar level. However. unburned ethanol and acetaldehyde emissions increased. The conversion efficiency of Pt/Rh based three-way catalysts and the effect of ethanol on CO and NOx emissions were investigated by the change of engine speed. load and air/fuel ratio. Furthermore, the ethanol blended fuel results in the reduction effect of THC. CO and NOx emissions at idle speed.
Study on the Single-Phase Heat Transfer and Pressure Drop Characteristics of R-718 in Small Diameter Tubes
Journal of the Korean Society of Marine Engineering, volume 28, issue 3, 2004, Pages 522~530
Single-phase heat transfer coefficients and pressure drops of R-718 were measured in smooth, horizontal copper tubes with inner diameters of 3.36 ㎜, 5.35 ㎜. 6.54 ㎜ and 8.12 ㎜, respectively. The experiments were conducted in the closed loop, which was driven by a magnetic gear pump. Data are presented for the following range of variables : Reynolds from 1000 to 20000. Single-phase heat transfer coefficients increased by 10∼30 % as the inner diameter of tube was reduced and it was found that a well-known previous correlation, Gnielinski's correlation was not suitable for the small diameter tubes. But the pressure drop in the small diameter tubes have been shown slightly deviations with Blauius' correlation. Based on an analogy between heat and mass transfer. the new heat transfer correlation is proposed to predict the experimental data successfully.
Dynamic and Static Characteristics of Sensor Tube for Mass Flow Controller
Journal of the Korean Society of Marine Engineering, volume 28, issue 3, 2004, Pages 531~537
In this paper, the static and dynamic characteristics in the sensor tube of a mass flow controller(MFC) were studied by experiments. In the sensor tube of MFC. the difference of temperature between inlet and outlet was necessary for calculating the mass flow rate. Therefore, the relations among flow rate, heat generated by heating wire. and sensor location were investigated to find optimized condition. Finally, the relation between sensor voltage through analog digital conversion(ADC) and flow rate in the sensor tube can be represented. Based on this study, static and dynamic characteristics of sensor tube can be used for design of mass flow controller.
Temperature Distribution and Thermal Stress Analyses of a Large LPLi Engine Piston
Journal of the Korean Society of Marine Engineering, volume 28, issue 3, 2004, Pages 538~550
The convection heat transfer coefficients on the top surface of a large liquid petroleum liquid injection(LPLi) engine piston with the oil gallery are analyzed by solving an inverse thermal conduction problem. The heat transfer coefficients are numerically found so that the difference between analyzed temperatures from the finite element method and measured temperatures is minimized. Using the resulting heat transfer coefficients as the boundary condition, temperature of a large LPLi engine piston is analyzed. With varying cooling water temperature, temperature, stress, and thermal expansion of the piston are analyzed and evaluated.
A Study on Optimal Combustion Conditions with a Design and Manufacture of the Long-Stroke Slow Speed 4 Cycle Diesel Engine
Journal of the Korean Society of Marine Engineering, volume 28, issue 3, 2004, Pages 551~558
Recently, fuel prices have been continually raised in diesel engine. Such a change in the fuel price influences enormously the development trend of marine diesel engines for slow speed, In other words, the focus was shifted from large diameter and high speed to low fuel consumption. Accordingly, more efforts are being made for engine manufacturing and development to develop highly efficient engines. In this study. a single cylinder 4 stroke cycle DI slow speed diesel engine was designed and manufactured, a 4 stroke cycle was configured and basic performances were evaluated. The results are as follows. The optimal fuel injection timing had the lowest value when specific fuel consumption was in BTDC 8~
, a little more delayed compared to high speed diesel engines. Cycle variation of engines showed about 5% difference at full loads. This is a significantly small value compared to the cycle variation in which stable operation is possible, showing the high stability of engine operation is good. The torque and brake thermal efficiency of engine increased with an increase of engine 250-450 rpm. but fuel consumption ratio increased from the 450 rpm zone and thermal efficiency abruptly decreased. Mechanical efficiency was maximally 70% at a 400 rpm that was lower than normal engines according to the increase of mechanical frictional loss for cross head part. The purpose of this study was to get more practical engines by comparing the above results with those of slow speed 2 stroke cycle diesel engines.