Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Society of Marine Engineering
Journal Basic Information
Journal DOI :
Korean Society of Marine Engineers
Editor in Chief :
Volume & Issues
Volume 26, Issue 6 - Nov 2002
Volume 26, Issue 5 - Sep 2002
Volume 26, Issue 4 - Jul 2002
Volume 26, Issue 3 - May 2002
Volume 26, Issue 2 - Mar 2002
Volume 26, Issue 1 - Jan 2002
Selecting the target year
Experimental Study on Accelerating Phase Change Heat Transfer
Journal of the Korean Society of Marine Engineering, volume 26, issue 1, 2002, Pages 23~29
Solid-liquid phase change (i.e. melting or solidification) occurs in a number of situations of practical interest. Some common examples include the melting of edible oil, metallurgical process such as casting and welding, and materials science applications such as crystal growth. Therefore, due to the practical importance of the subject, there have been a large number of experimental and numerical studies of problems involving phase change during the past few decades. Also, this study presented the effective way to enhance phase change heat transfer.
The characteristics of deep slot outside rotor type IM
Journal of the Korean Society of Marine Engineering, volume 26, issue 1, 2002, Pages 30~36
This paper presents a developed deep slot squirrel cage induction motor fur the fan. Nearly all of the induction motors consist of two parts, rotor and stator, and the position of rotor is generally inside of stator. However, the rotor of the developed induction motor is located outside of stator. It is believed that the outside rotor type induction motor is suitable for the fan due to its large inertia, that is, it is considered that the change of air flow rate resulting from input power or load fluctuation is reduced. It is considered that the results of this paper can be used for the development of the outside rotor type induction motor.
Study on the Characteristics of Performance and Exhaust Emissions of 3-Chamber GDI Engine
Journal of the Korean Society of Marine Engineering, volume 26, issue 1, 2002, Pages 37~47
Recently gasoline direct injection method has been applied to gasoline engine to reduce fuel consumption rate by controlling fuel air mixture on lean condition by means of stratified charging, and to reduce simultaneously. Pollutant emissions especially NOx and CO by lowering the combustion temperature. But difficulty of controling local fuel air ratio at ignition area in flammability limit unavoidably appeared, because it is merely controlled by injection timing with spatial and temporal distribution of fuel mixture. In this study, the authors devised a uniquely shaped combustion chamber so called three-chamber GDI engine, intended to keep the more reliable fuel air ratio at ignition area. The combustion chamber is divided into three regions. The first region is in the rich combustion division, where the fuel is injected from the fuel injection valve and ignited by the spark plug. The second region is in the lean combustion division, where the combustion gas from the rich combustion division flows out and burns on lean condition. And the last region is in the main combustion division ie in the cylinder, where the gas from the above two combustion divisions mixed together and completes the combustion during expansion stroke. They found that the stable range of operation of three-chamber GDI engine on low-load condition exists in the lean area of average equivalence ratio. And they also found that the reformed engine reveals less specific fuel consumption and less pollutant emissions compared with conventional carburettor type gasoline engine.
A Study on Optimum Modification of Dynamic Characteristics of Stiffened Plate Using Simplified Equation of Natural Frequency
Journal of the Korean Society of Marine Engineering, volume 26, issue 1, 2002, Pages 48~58
There is a purpose of this study for the proposal of the optimum technique utilized for the vibration design initial step. The stiffened plate structure for the ship hull is made for analysis model. To begin with, dynamic characteristics of stiffened plate structure is analysed using FEM. Main vibrational mode of the structure is decided in the analytical result of FEM. The simplified equation on the natural frequency of the main vibrational mode is induced. Next, sensitivity analysis is carried out using the simplified equation, and rate of change of dynamic characteristics is calculated. Then, amount of design variable is calculated using this sensitivity value and optimum structural modification method. The change of natural frequency is made to be an objective function. Thickness of panel, cross section moment of stiffener and girder become a design variable. The validity of the optimization method using simplified equation is examined. It is shown that the result effective in the optimum modification for natural frequency of the stiffened plate structure.
On Reliability and Comparison of
-Resistance considering Optimal Strength Ratio and
-Resistance Curves converted from CTOD using Appropriate Strength chosen according to Strain Hardening Level
Journal of the Korean Society of Marine Engineering, volume 26, issue 1, 2002, Pages 59~67
The comparison of
-resistance considering a few strength ratio in Rice J-integral formula and
-resistance curves converted from experimental CTOD using appropriate strength chosen according to strain hardening level, n=10.6 (A533B steel) and n=8.1 (BS4360 steel) is carried out. The optimal dimensionless strength ratio like the factor of revision, (see full text)reflecting strain hardening level in Rice\`s experimental formula is found out and the reliability of appropriate reference strength chosen according to strain hardening level in different materials is investigated through doing that CTOD is transformed from
-integral using relationship between J-integral and CTOD. The results are as follows; 1) The optimal factor of revision is when m equals to 3 in (see full text) for Rice's and the above optimal factor of revision multiplies by coefficient, η in Rice's experimental formula instead of n=2, 2) and the pertinent reference strength for high strain hardening material like BS4360 steel is ultimate strength,
and for material like A533B steel is ultimate-flow strength,
. The incompatible of the behavior of both experimental J-resistance curves using Rice's formula and CTOD-resistance curves for A533B and BS4360 steel by Gordon, et al., could be corrected using the optimal factor of revision in Rice\`s and the pertinent reference strength in J=
The effect of aging on the Microstructure and Hardness of Stellite 12 alloy overlayer by PTA process
Journal of the Korean Society of Marine Engineering, volume 26, issue 1, 2002, Pages 68~75
Stellite 12 alloy-powders were overlaid on 410 stainless steel valve seat by plasma transferred arc(PTA)process. Variation of microstructure and hardness of overlaid deposit with aging time at
was investigated. The deposit showed hypoeutectic microstructure, which was consisting of primary cobalt dendrite and networked
type eutectic carbides. After aging new
carbide was formed by the partial decomposition of
type eutectic carbides and finely dispersed
type carbides were also precipitated in the matrix. Hardness of the deposit was increased with increase of aging time at
and showed maximum value at 35hours. After showing maximum value, it was fallen down again at 70hours because of overaging. The increase of hardness in aging is ascribed to the formation of new stable
type carbide by the partial decomposition of $M_7C_3$ type eutectic carbides and also precipitation of finely dispersed
carbides in matrix.
The Influence of Grain Size on the Fatigue Crack Propagation Behavior in the Low Carbon Steel (SM26C)
Journal of the Korean Society of Marine Engineering, volume 26, issue 1, 2002, Pages 76~82
In this study, the rotary bending fatigue test was carried out with low carbon steel(SM25C). The specimens were heat-treated in order to change the grain size, and investigated items are fatigue limit, small crack initiation, fatigue crack propagation behavior and possibility of fatigue life prediction according to the different grain size. The summarized result are as follows ; Fatigue limit of the smooth specimen was dependent upon the grain size. The fatigue crack initiation of the small grain size specimen was delayed more than that of the large grain size specimen. And the small cracks of small grain size specimen were distributed in the narrow region of the main crack circumference contrary to the large grain size specimen. The main crack was grown along the grain boundary having co-alliance with small cracks. The experiment material has quantitatively disclosed the possibility of fatigue life prediction because the fatigue crack propagation behavior is dependent upon the grain size.
A Study on the Effect of Fin Pitch of Offsets Strip Fin on Heat Transfer of High Prandtl Fluid
Journal of the Korean Society of Marine Engineering, volume 26, issue 1, 2002, Pages 83~89
In the present study, heat transfer characteristics of oil flow over offset strip fins were predicted by the numerical methods. Oil flow in the plate-fin passage was idealized by 2 dimensions. The flow patterns and heat transfer characteristics were predicted in details. Numerical results shows that the average convective heat transfer coefficients are almost independent on the raws of fins and affected by fin pitches. At the rear face of fin, there exists minimum point of heat transfer coefficients where stream are separated from the fin surfaces. The convective heat transfer coefficients were effected by separation bubbies which appeared at the wake region of offset strip fins.
A Study of Annealing Heat-treatment for Ti(Grade 2) by Electrochemical Methods
Journal of the Korean Society of Marine Engineering, volume 26, issue 1, 2002, Pages 90~98
In this paper, the annealing heat treatments for the best corrosion resistant of Ti(Grade 2) were studied in a 3.5% NaCl solution by electrochemical methods. The annealing heat treatments were accomplished at 650, 700 and
with different time of 30min., 1hour and 2 hours in a vacuum condition. The obtained results are: 1) in the case of solution heat treated
for 2 hours in a vacuum and air, the corrosion potentials were -348.7 and -567. 1mV, and current densities 2.32 and
, respectively, 2) as increase both annealing heat treatment temperature 650, 700,
and time 30min., 1 hour, 2 hours, the corrosion potential were decreased, whereas corrosion current density increased, 3) in the case of cyclic polarization, the measured charges were increased as increasing solution heat treatment temperature and time, 4) on the bases of corrosion potential, current density and charge, the best annealing temperature and time were measured as
and 30min. for Ti(Grade 2) material.
An Electrochemical Study on the Corrosion Property of Materials for Sea Water Heat Exchange System
Journal of the Korean Society of Marine Engineering, volume 26, issue 1, 2002, Pages 99~107
Recently all kinds of structural materials are subjected to the severe corrosive environment. Especially corrosion problems of heat exchanger such as galvanic corrosion, erosion and cavitation raised by both contaminated solution and high velocity of fluid to increase cooling effect of heat exchanger have been frequently reported in these days. In this study two kinds of sheet materials and five kinds of tube materials are used for galvanic corrosion characteristics and their corrosion current density calculation. The tube materials having the most galvanic corrosion resistance between tube and sheet of heat exchanger were Al Brass(68700) and Al Brass(C6872TS) and although Ti tube predominantly indicated the highest individual corrosion resistance among those five tube materials. it appeared that Ti tube can be allowed as sheet materials to get galvanic corrosion easily. However it is considered that Cu-Ni tube materials is not only easy to produce galvanic corrosion significantly between tube and sheet regardless of kinds of sheet materials but also is appeared considerably its own high corrosion current density
Time Historical Response Analysis of Three Dimensional Rectilinear Structure using the TSCM
Journal of the Korean Society of Marine Engineering, volume 26, issue 1, 2002, Pages 108~115
This paper suggests a new analysis algorithm for the time historical response of three dimensional rectilinear structure which is frequently found in a pipe line system of plant by the combination of the transfer stiffness coefficient method(TSCM) and the Newmark method. The present analysis algorithm for a time historical response can improve the computational accuracy and time remarkably owing to advantages of the TSCM in comparison with transfer matrix method(TMM). The structural system is modeled as a lumped mass system in this method. The analysis algorithm was formulated far the three dimensional rectilinear structure. We confirmed the validity of the present algorithm by comparing the numerical computation results of TSCM with those of TMM.
Nonlinear Behaviors of a Gas-filled Bubble Oscillator with Large Amplitude of Excitation
Journal of the Korean Society of Marine Engineering, volume 26, issue 1, 2002, Pages 116~124
The bubble model by Keller and Prosperetti is adapted to solve the nonlinear oscillation of a gas bubble. This formulation leads to accurate results since it introduces the energy equation instead of the polytropic assumption for the bubble interior. The numerical method used in this study is stable enough to handle large amplitude of bubble oscillation. The numerical results show some interesting nonlinear phenomena fur the bubble oscillator. The excitation changes the natural frequency of the bubble and makes some harmonic resonances at
and so on. The natural frequency of a bubble oscillator decreases compared with the linear case result, which means that the nonlinear bubble oscillation system is a "softening"system. In addition, the frequency response curve jumps up or down at a certain frequency. It is also found that there exist multi-valued regions in the frequency response curve depending on the initial conditions of bubble. The dependency of the bubble motion on the initial condition can generate extremely large pressure and temperature which might be the cause of the acoustic cavitation and the sonoluminescence.inescence.
The Effect of Temperature on Corrosion of Absorption Refrigeration Systems Using
Journal of the Korean Society of Marine Engineering, volume 26, issue 1, 2002, Pages 125~131
This paper was studied on the effect of temperature on corrosion of absorption refrigeration systems using
working fluids. In the fresh water and 62 % lithium bromide solution at
, polarization test of SS 400, Cu(C1220T-OL) and Al-Ni bronze was carried out. And polarization behavior, polarization resistance characteristics, corrosion rate(mmpy) and corrosion sensitivity of materials forming absorption refrigeration systems was considered. The main results are as following: (1) As the experimental temperature increase, the change of corrosion rate of Al-Ni bronze become duller than SS 400 and Cu in 62% lithium bromide solution. (2) According as corrosion environment is changed from fresh water to 62% lithium bromide solution, potential change of Cu and Al-Ni bronze become less noble than SS 400. (3) The corrosion sensitivity of Al-Ni bronze was duller than that of Cu and SS 400 in 62% LiBr solution.
A Study on the Evaporation and Ignition of Single Fuel Droplet on the Hot Surface
Journal of the Korean Society of Marine Engineering, volume 26, issue 1, 2002, Pages 132~137
Recently, impinging spray is used for atomization of diesel engine, but it bring on adhesion of fuel. Therefore, we studied about droplet behavior on high temperature plate changing the size of droplet, surface temperatures, and surface roughness of plate. In this study, We studied to confirm experimentally about mechanism of evaporation and ignition process of single fuel droplet. We observed evaporation time, evaporation appearance and ignition delay time by the photopraphs of 8mm video camera. Experimental results are summarized as follows: 1. The boiling point of fuel affect a evaporation and ignition process. 2. The surface roughness affect a evaporation time. 3. The ignition delay time relate to evaporation characteristic.