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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 19, Issue 4 - Aug 1995
Volume 19, Issue 3 - Jun 1995
Volume 19, Issue 2 - Apr 1995
Volume 19, Issue 1 - Feb 1995
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A Study on the Design of Liquid Flow Control Valves for the Pants and Ships(II)
Journal of the Korean Society of Marine Engineering, volume 19, issue 2, 1995, Pages 1~9
The processing paper has devoted to the theory of the flow equations, the basic derivative procedure, the meaning of a valve flow coefficient
, the valve Reynolds R
and its application for liquid control valves, which applicable under the condition of a non-critical flow and the case of piping geometry factor
=1.0. However there is no information on the effects of fittings, a critical flow and the flow resistance coefficient of a valve equivalent to that of pipe which is conveniently used in the piping design. Since the piping systems of plants or ships generally contain various fittings such as expanders and reducers due to different size between pipes and valves and there may occur a critical flow, that a mass flowrate is maintained to be constant, due to the pressure drop in a piping when a liquid is initially maintainder ar a saturated temperature or at nearby corresponding to upstream pressure, system designer should have a knowledge of the effect to flow due to fittings and the critical flow phenomenon of a liquid. This study is performed to inform system designers with the critical flow phenomenon of a liquid, a valve resistance coefficient, a valve geometry factor and their applications.
A Numerical Analysis of Characteristics of Combined Heat Transfer in Laminar Layer Along Cylinderical Periphery by P-N Method
Journal of the Korean Society of Marine Engineering, volume 19, issue 2, 1995, Pages 10~19
Heat trnasfer for absorbing and emitting media in laminar layer along the cylinders has been analyzed. Governing equation are transformed to local nonsimilarity equations by the dimensional analysis. The effects of the Stark number, Prandtl number, Optical radius and wall emissivity are mainly investigated. For the formal solution a numerical integration is performed and the results are compared with those obtained by P-1 and P-3 approximation. The results show that boundary layers consist of conduction-convection-radiation layer near the wall and convection-radiation layer far from the wall. As the Stark number of wall emissivity increases the local radiative heat flux is increased. The Pradtl number or curvature variations do not affect the radiative heat flux from the wall, but The Prandtl number or wall emissivity variations affect the conduction heat flux. Consequently the total heat flux from the wall are affected by the Prandtl number or wall emissivity variation.
A Study on the Heat Transfer of Carbon Steels in Quenching
Journal of the Korean Society of Marine Engineering, volume 19, issue 2, 1995, Pages 20~26
The very rapid cooling problem from
C on the surface of the steel by thermal conduction including the latent heat of phase transformation of steel and by transient boiling heat transfer of water are considered to principal problem in quenching. The transient boiling process of water at the surface of specimen during the quenching process were experimentally analyzed. Then the heat flux was numerically calculated by the numerical method of inverse heat condition problem. In this report, the simulation program to calculate the cooling curves for large rolls was made using the subcooled transient boiling curve as a boundary condition. By this simulation program, the cooling curves of rolls from D=50mm to D=200mm were calculated and the effects of agitation of circulation of water also investigated.
Double-Diffusive Convection in Molten Pb-Sn Alloy
;Bergman, T. L.;
Journal of the Korean Society of Marine Engineering, volume 19, issue 2, 1995, Pages 27~35
A Study on the Behavior of Fatigue Crack Propagation in Marine Propeller Shaft Materials with Small Circular Defect
Journal of the Korean Society of Marine Engineering, volume 19, issue 2, 1995, Pages 36~46
In this paper, fatigue crack propagation behaviors were investigated experimentally for the materials, carbon steel forgings (SF45A, SF50A, SF60A) which are used in the marine propeller shaft. The results obtained are as follows: The number of cycles required to grow crack length 1.30mm from microcrack initiation was about 60% of the total fatigue life. Fatigue crack propagation rate was expressed by the equation d(2a)/dN_B 2a/
and the result was agreed well with the experimented data. And the equation d(2a)/dN=
was evaluated also. Obtained material property m and n are 3~5 and 1-1.5 respectably, and the result was reasonably agreed to the data obtained from experiments.
A Study on Chromium Electroplating of Piston Ring Groove's Surface
Journal of the Korean Society of Marine Engineering, volume 19, issue 2, 1995, Pages 47~55
When the low heavy oil is using as fuel oil to the diesel engine, some problems such as corrosion resistance, wear resistance and heat resistance are happened in diesel engine's internal material, especially the adhesive wear of piston ring groove was occurred as a important problem. Therefore to prevent adhesive wear of its groove, the surface of its groove used to be electroplated with Chrominum and for its Chromium electroplating, Fe anode is being used until nowadays because of its Special shape. However in case of using Fe anode, there were some problems such as deterioation of solution, property of Chromium film, and condition of coation. In this paper Pb anode electroplated withPb to the steel plate was investigated for its Chromium electroplating for Pb's high corrosion resistance in acid solution, and Pb anode is not dissolved compared with Fe anode and deterioration degree of solution in case of Pb anode is smaller than that of Fe anode and also property of Chromium film was better than that of Fe anode. Moreover it was known that the optimum cathodic current density for Pb electroplating to steel plate as insoluable anode for Chromium coating of piston ring groove is 30mA/
by experimental results obtained.
Fundamental Study on Cathodic Protection and Material Development as Erosion-Control Methods of Oceanic Centrifugal Pump(1)
Journal of the Korean Society of Marine Engineering, volume 19, issue 2, 1995, Pages 56~66
Recently, with theraped advancement in th oceanology such an ocean-going vessel and oceanic structures, there is a need to study the cavitation erosion-corrosion control of pump impeller, the partial element of ocean machinery, for more effective operation. Especially, the cathodic protection (impressed current method & Al-sacrificial anode method) was applied to sea water, and Cu-alloy material mixed Zn & Al was used as a control method of cavitation erosion-corrosion. In this study, used the piezoelectric vibrator with 20KHz, 24.mu.m to cavity generation apparatus, and investigated the weight loss, weight loss rate, electrode potential & current density etc. under this condition. According to test result, thos describes how to indentify an influence of the cathodic protection and Al & Zn addition in material development for the control of cavitation erosion-corrosion, and those will serve as fundamental data on the cavitation erosion-corrosion control of oceanic centrifugal pump.
A Study on the Robust Control of Systems Dominantly Subkected to Modeling Errors and Uncertainties
Journal of the Korean Society of Marine Engineering, volume 19, issue 2, 1995, Pages 67~80
In order to control systems which are dominantly subjected to modeling errors and uncertainties, control strategies must deal with the effect of modeling errors and uncertainties. Since most of control methods based on system mathematical model, such as LQG/LTR method, have been developed mainly focused on stability robustness, they can not smartly improve the transient response disturbed by modeling errors and/or uncertainties. In this research, a fuzzy PID control method is suggested, which can stably improve the transient responses of systems disturbed by modeling errors as well as systems not entirely using mathematical models. So as to assure the effectiveness of suggested control method, computer simulations are accomplished for some example systems, through the comparison of transient responses.
A Study on Development of Miniature Size Surface Charge Electrostatic Induction Motor
Journal of the Korean Society of Marine Engineering, volume 19, issue 2, 1995, Pages 81~91
A miniature size electrostatic induction motor has been fabricated and studied with emphasis on the role of the surface resistivity, the relative dielectric constant of the rotor surface materials and the rotor liner materials, which control the charge induction and relaxation on the rotor surface and the field intensity between the rotor and the stator. It is found that the higher resitivity and/or the higher relative dielectric constant, concurrently the longer relaxation time constant of the rotor surface materials make the motor speed get higher speed. In case of discrete coated rotor surface it is found that the motor speed was increased logarithmically as narrow as width of the discrete coated Ti. And the degree of width of discrete coated Ti to the axial direction of the rotor was
, the motor has got a 125% higher than that at the degree of