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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
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Volume & Issues
Volume 22, Issue 6 - Nov 1998
Volume 22, Issue 5 - Sep 1998
Volume 22, Issue 4 - Jul 1998
Volume 22, Issue 3 - May 1998
Volume 22, Issue 2 - Mar 1998
Volume 22, Issue 1 - Feb 1998
Selecting the target year
System Intelligence and Electronic High Speed On-Off Valves
Journal of the Korean Society of Marine Engineering, volume 22, issue 3, 1998, Pages 267~274
A Study on the Development of Computer Software for the Design of Fire Protection System
Journal of the Korean Society of Marine Engineering, volume 22, issue 3, 1998, Pages 275~284
Standard on the carbon dioxide extinguishing system was prepared by the committed of the national fire protection assocition(NFPA)in USA on 1980. And this code is also applied to the design of a marine fire extinguishing system The most important problem in design is the uniform discharge of
through each nozzle from the high pressure
storage facility. The purpose of this paper is to develop the computer software to design the marine fire protection piping system. By solving the continuity equation energy equation and Bernoulli's equation simulataneously the flowrate in branch pipelines and discharge nozzles can be calculated.
Condensing Heat Transfer Charactristics of R-22 Alternative Refrigerants on Water Sources Heat Pump
Journal of the Korean Society of Marine Engineering, volume 22, issue 3, 1998, Pages 285~293
This paper presents an experimental study on condensing heat transfer characteristics of R-22 alternative refrigerants, R-290 and R-410a on water sources heat pump. The apparatus mainly consisted of vapor pump condenser used to the test section evaporator manual expansion valve and measuring device. Test section constructed a smoothed tube of 10.07 mm ID and 12.7mm OD with a total length 6,300 mm was horizontal double pipe counterflow condenser. The refrigerants R-22, R-290 and R-410a were cooled by a coolant circulated in a surrounding annulus. Experimental range of mass velocities was changed from about 100 to 300 kg/(
.s) and inlet quality 1.0 The credibility of experimental apparatus was 6 percent between heating capacity and cooling capacity added to compressor shaft power. The condensing heat transfer coefficients were increased with increasing mass velocity. However in case of R-290 they were more increasing than those of R-410a and R-22 Comparing the heat transfer coefficient between the experimental data and other's data the Cavallini-Zecchin's data was revealed to more similar prediction of author's experimental results on the average heat transfer coefficients.
A Numerical Study on the Convective Mass Transfer in Horizontal Rectangular Enclosures
Journal of the Korean Society of Marine Engineering, volume 22, issue 3, 1998, Pages 294~302
The charateristics of the convective mass transfer in horizontal rectangular enclosure with horizontal concentration gradients are analyzed. The effect of Grashof number(Gr) and aspect ratio(L/H) is investigated numerically using the control-volume method. Numerical results are obtained for Grashof numbers between
aspect ratios from 1 to 100 and results are compared with existing andlytical results. It is found that there exists a well defined aspect ratio for which the mean Sherwood number is maximum and the core flow changes from parallel to non-parallel at
and in the Ralongrightarrow0 regime the numerical results agreed very well with correlation derived from analytical results.
Prediction of Asymmetric Turbulent Fluid Flow and Heat Transfer in the Parallel Plates
Journal of the Korean Society of Marine Engineering, volume 22, issue 3, 1998, Pages 303~310
We report on the analytical results of examination of fully developed asymmetric flow and heat transfer between parallel plane plates. The asymmetry was introduced by roughening one of the plane while the other was left smooth. The integral method together with a turbulence model based on modified Prandtl's mixing length theory for the rough was used to determine the velocity distribution and friction. The temperature distrtibution is then predicted and heat transfer coefficients are calculated. The present paper shows that the heat transfer increases more than the friction factor for a given roughness structure. Generally the results show the strong effect of asymmetry on engineering parameters. Furthermore it is the roughness structure which influences the nature of asymmetry and heat transfer.
A Study on the Speed Control of a Sensorless DC Motor by using a Fuzzy Controller
Journal of the Korean Society of Marine Engineering, volume 22, issue 3, 1998, Pages 311~319
DC Motors have been widely used in industry as driving power motors for electrical vehicles cranes and winches due to their strong starting torques and as servo-motors for position and speed control systems due to their convenience of speed control etc. Generally in the speed control systems of motors speed sensors are required and this fact results in he increased price and operating cost and in the limitted applications. This paper presents a new speed control method for sensorless DC motors. In this scheme the speed signal is estimatd by the measurement values of the armature voltage and current. A Fuzzy feedback controller instead of the conventional PID controller. Through simulations the effectiveness and usefullness of the proposed method are illustrated.
An intelligent Speed Control System for Marine Diesel Engine
Journal of the Korean Society of Marine Engineering, volume 22, issue 3, 1998, Pages 320~327
The purpose of this study is to design the intelligent speed control system for marine diesel engine by combining the Model Matching Method and the Nominal Model Tracking Method. Recently for the speed control of a diesel engine some methods using the advanced control techniques such as LQ control Fuzzy control or H
control etc. have been reported. However most of speed controllers of a marine diesel engine developed are still using the PID control algorithm But the performance of a marine diesel engine depends highly on the parameter setting of the PID controllers. The authors proposed already a new method to tune efficiently the PID parameters by the Model Mathcing Method typically taking a marine diesel engine as a non-oscillatory second-order system. It was confirmed that the previously proposed method is superior to Ziegler & Nichols's method through simulations under the assumption that the parameters of a diesel engine are exactly known. But actually it is very difficult to find out the exact model of the diesel engine. Therefore when the model and the actual diesel engine are unmatched as an alternative to enhance the speed control characteristics this paper proposes a Model Refernce Adaptive Speed Control system of a diesel engine in which PID control system for the model of a diesel engine is adopted as the nominal model and a Fuzzy controller is adopted as the adaptive controller, And in the nominal model parameters of a diesel engine are adjusted using the Model Matching Method. it is confirmed that the proposed method gives better performance than the case of using only Model Matching Method through the analysis of the characteristics of indicial responses.
A Study on the Forced Torsional Vibration of Engines Shafting Systems with Non-linear Elastic Couplings
Journal of the Korean Society of Marine Engineering, volume 22, issue 3, 1998, Pages 328~336
Marine reduction gears are usually used to increase the propulsion efficiency of propellers for ships powered by medium and small sized high speed diesel engines. Most of shaft systems adopt flexible couplings to absorb the transmitted vibratory torque from the engines to the reduction gears and to prevent the chattering phenomenon of reduction gears. However some elastic couplings show non-linear characteristics due to the variable torque transmitted from the main engines and the change of ambient temperature. In this study dynamic characteristics of flexible couplings sare investigated and their effects upon various vibratory conditions of propulsion systems are clarified. A calculation program of torsional vibration for the propulsion systems are clarified. A calculation program of Results of the program developed are compared with ones of the existing linear method and propulsion systems with the elastic couplings the transfer matrix method is adopted which is found to give satisfied results.
Comparison of the Performance of Pivoted Pad Thrust Bearings
Journal of the Korean Society of Marine Engineering, volume 22, issue 3, 1998, Pages 337~342
In this paper the lubrication performances of line pivoted pad thrust bearing and point pivoted pad thrust bearing are studied by a numerical analysis. The running characteristic parameters such as nondimensional load carrying capacity nondimensional friciton power loss nondimensional flow rate and film thickness ratios are calculated for various circumferential pivot positions. The results provide a usdful data for the selection of pivot position in a pivoted and thrust bearing.
A Study on the Design of the Class E Resonant Rectifier with a Series Capacitor
Journal of the Korean Society of Marine Engineering, volume 22, issue 3, 1998, Pages 343~352
Higher frequency of energy transfer or at least energy conversion has to be used in order to reduce the size of inductors and capacitors required in the power supplies. Conventional PWM switching-mode power supplies have a limitation of operating frequency due to switching losses in the switching transistors and rectifier diodes. Means of reducing switching losses have been developed for high-frequency resonant amplifiers or more exactly dc/ac inverters. Because of smooth current and voltage waveforms resonant convertesrs havelower device switching losses and stresses lower electromagnetic interference(EMI) and lower noise than PWM converters. Therefore in this paper design equations of Classs E resonant low dv/dt rectifier with a series resonant capacitor drived using Fourier series techniques. The theory is compared with simulation results obtained for the rectifier operating at 10[MHz] ac input and 5[V] coutput.
Free Vibration Analysis of Annular Sector Plates Using Time Average Holographic Interferometer
Journal of the Korean Society of Marine Engineering, volume 22, issue 3, 1998, Pages 353~361
The study on the vibration characteristics of annular sector plates is important for structural engineers. In this study the vibration modes and their natural frequencies of annular sector plates clamped along the inner circumferential edge are obtained by the time average holographic interferometer according to the varying sector angle. The experimental results agree well with those obtained by the numerical analysis. The vibration characteristics of annular sector plates shows great dependence on the sector angle. The radial nodal lines converge to the center of annular sector plate.
Enhancement of Heat and Mass Transfer for a Vertical Type Absorber
Journal of the Korean Society of Marine Engineering, volume 22, issue 3, 1998, Pages 362~370
Absorption systems require a heat source for working but they have a great merit in that relatively low-temperature and low-quality types of thermal energy such as solar heat and exhaust heat can be effectively utilized as heat source. However details research related to absorbers which have a great effect on performances has been rarely done and thus there has been a strong hope for positive developments to improve their efficiencies. This paper describes absorption experiments made with different inside tube diameters and shapes. The purpose of this study is to acquire basic knowledge about heat and mass transfer in a falling film type absorber with vertical inner tubes. Heat and mass transfer were measured for water vapor absorption into a water/LiBr solution flowing down an absorber of vertical inner tubes. As a result absorption acceleration tube compares bare tube and heat transfer improved by order of insert spring tube corrugated tube grooved tube. And the acceleration that is good provided in inserting spring tube for both sides of heat and mass transfer.
Flowfield Calculation for Ship's Propulsion Mechanism of Two-Stage Weis-Fogy Type
Journal of the Korean Society of Marine Engineering, volume 22, issue 3, 1998, Pages 371~380
The flow patterns and dynamic properties of ship's propulsion mechanism of two-stage Weis-Fogh type are studied by the discrete vortex method. In order to study the effects of the interaction of the two wings two cases of the phase differences of the wing's motion are considered the same phase and the reverse phase. The flow patterns by simulations correspond to the photographs obtained by flow visualization and flowfield of the propulsion mechanism which is unsteady and complex is clearly visualized by numerical simulations. The time histories of the thrust an the drag coefficients on the wings are also calculated and the effects of the interaction of the two wings are numerically clarified.
Decision Method of Optimal Engine System for High-Speed Ship by Analytical Hierarchy Process
H.B. Ro ;
Journal of the Korean Society of Marine Engineering, volume 22, issue 3, 1998, Pages 381~395
The purpose of this study is to determine the optimal gas turbine system for special purpose ships. First we generate critical evaluation criteria an construct their hierarchical structure. The criteria consist of qualitative ones as well as the economic factor. Then AHP is applied to solve the decision making problem AHP gibes good results different from those only by the economic evaluation methods. And during the analysis, the procedure produces many useful informations to the decision making. The results shows that AHP is an appropriate method for these kinds of problems such as the system selection.
Numerical Analysis on Transient Response of Turbine Blandes by Partial Admission
Journal of the Korean Society of Marine Engineering, volume 22, issue 3, 1998, Pages 396~404
A numerical analysis is presented for the transient behavior of a rotating turbines blades. The response due to partial admission during start-up and resonance pass is considered, Modal analysis and numerical integation method are used for solving the problems A theory for determining the material and aerodynamic damping values of turbine blades is presented. The damping values of the various modeling of blaes-uniform beam and tapered twisted beam-are calculated and the influence on blades response is investigated. The effect of angular velocity on transient response are also shown.
A Study on the Method for Calculating the Reliability of Diesel Engines in Operation
Journal of the Korean Society of Marine Engineering, volume 22, issue 3, 1998, Pages 405~410