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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Ocean Engineering and Technology
Journal Basic Information
Journal DOI :
Korean Society of Ocean Engineers
Editor in Chief :
Volume & Issues
Volume 13, Issue 4 - Nov 1999
Volume 13, Issue 3 - Aug 1999
Volume 13, Issue 3B - Aug 1999
Volume 13, Issue 2 - May 1999
Volume 13, Issue 1 - Feb 1999
Volume 13, Issue 4 - 00 1999
Selecting the target year
Today and Future of Our Ocean Resources Development Equipments(II)-Prospective Developments
Oh, Sae-Kyoo ;
Journal of Ocean Engineering and Technology, volume 13, issue 3B, 1999, Pages 1~2
Diffusion Analysis of the High Temperature and Salinity Water by the 3-D Baroclinic Flow Model
Kim, Jong-In ; Kim, Hyeon-Ju ;
Journal of Ocean Engineering and Technology, volume 13, issue 3B, 1999, Pages 3~13
The diffusion characteristics of the high temperature and salinity water discharged in Chinhae Bay under BMP(Barge-Mounted Plants) desalination processes were simulated to access environmental impact. The 3-D baroclinic flow model is formulated by integrating the basic equations with respect to each control volume and by transforming them into a finite difference form using the space-staggered grid system. With a 3-D baroclinic flow model, the tide-induced and density-induced current was computed and confirmed by comparing with observed data. From the results of numerical experiment, it is expected that the maximum diffusion lengths of the high temperature and salinity which increase
and 0.2 after discharging are 1 km and 3.5km, respectively. It may be expected that the discharge has an effect on surrounding area of discharge, but not an effect on whole area of Chinhae Bay.
A Study on Lifting Characteristics of Air-Lift Pump
Kim, Dong-Kyun ; Lee, Cheol-Jae ; Bae, Suk-Tae ; Cho, Dae-Hwan ;
Journal of Ocean Engineering and Technology, volume 13, issue 3B, 1999, Pages 14~21
As an effective means to convey crushed materials from seabed to onboard ship and to raise hazardous or abrasive liquids, air-lift pump provides a reliable mechanism due to its simple configuration and easy-to-operate principle. The present study is focused on investigation of related performance by the analysis program based on the gas-liquid two-phase flow in circular pipes. The program covers pump operating in isothermal and vertical two-phase flow with Newtonian liquids. It is summarized as important result that an optimum air mass flow rate exists for the maximum lifted liquid mass flow rate in terms of a given submergence rates. The comparison between riser performance of the conveyed liquid flow rate calculated by the computer program and measured data with large scale air lift pump system constructed in 200 meter depth vertical tank reveals similar distribution.
A Study on the NOx Emission of the Turbulent Diffusion Flame Formed behind the After Burner
Lee, U-Seop ; Kim, Gyu-Seong ; Kim, Tae-Han ; Lee, Do-Hyeong ;
Journal of Ocean Engineering and Technology, volume 13, issue 3B, 1999, Pages 22~28
The purpose of this study is to investigate the NOx emission of turbulent diffusion flame formed in the after burner, which is located on the waste gas coming out from the test furnace. Three types of flame was tested and each of which was changed by adequate equivalence ratio. It is necessary to study more about NOx reduction effect in the after burner system.
Characteristices of Temperature Distribution in a Closed Space with Heat Source and Porous Horizontal Partition
Park, Chan-Su ; Cho, Dae-Hwan ; Jeon, Cheol-Kyun ;
Journal of Ocean Engineering and Technology, volume 13, issue 3B, 1999, Pages 29~37
Ventilation of the marine engine room is very important for the health of the workers as well as the normal operation of machines. To find proper ventilation conditions of this engine room, numerical simulation with standard k-
model was carried out. In the present study, the marine engine room is separated to two floors with porus horizontal partition and considered as a closed space with a heat source and forced ventilation ducts. The porosity of horizontal partition is found to be important. For the engine room with 2 supply ports & 2 exhaust ports, the increasing of the porosity of horizontal partition is effective to reduce the recirculation flow zone in the second floor. When the engine room is ventilated with three supply air ports & one exhaust port, the increasing of the porosity of horizontal partition is effective to reduce the recirculating flow zone in the exhaust air area, but there is a possibility of local extreme heating at the lower side of engine near bottom.
A Study on Application of the Photo Detector for Electromagnetic Fuel Injection System of DI Diesel Engine
Ra, Jin-Hong ; Ahn, Soo-Kil ;
Journal of Ocean Engineering and Technology, volume 13, issue 3B, 1999, Pages 38~46
Increasing stringent emissions legislation and requirement of more effective energy used for diesel engine demand the fine control of the fuel injection system. Recently, the electromagnetic fuel injection control system for diesel engine is tried to realize the optimum diesel combustion by the feel back sensing as optical signal of combustion flame. The photo detectors were made for the feed back signal of electromagnetic fuel injection control for small DI diesel engine. Their abilities to detect defining combustion events were examined. By evaluating test results, it was shown that the wider acceptable optical range design of optical probe window face, and selection of installation position and installation method of detector were important point for improving sensing ability. The detector was shown to detect start and end of diffused combustion and maximum point of flame intensity impossible for pressure sensor, and also shown that the maximum point of flame intensity was 75% of accumulated heat release point within the experimental conditions.
The Effect of Combustion Chamber Shape on the Performance of Swirl Chamber in Diesel Engine(II)
Ra, Jin-Hong ;
Journal of Ocean Engineering and Technology, volume 13, issue 3B, 1999, Pages 47~55
A study on swirl chamber for diesel engine is to realize lower fuel consumption and exhaust emission than the current marketing engines. Author formerly reported the performance characteristics of small IDI diesel engine with swirl chamber by changing the jet passage area and its angle, and the depth and shape of the piston top cavity. Following after the first report, in this paper, the characteristics of fuel consumption, soot emission, and exhaust gas temperature were examined and analyzed after dimension of jet passage area expanded to
The results were that the optimum values of the jet passage area depending on the depth of the piston top cavity were different at each engine speeds and loads, and in accordance with application of engine running conditions they were able to be selected as optimum dimensions of each design parameters.
An Experimental Study on Shear Strengthening of the R/C Deep Beams Using Carbon and Aramid Fibers
Jo, Byung-Wan ; Kim, Young-Jin ;
Journal of Ocean Engineering and Technology, volume 13, issue 3B, 1999, Pages 56~64
An experimental study was carried out to examine the structural behavior of reinforced concrete deep beams strengthened with aramid fiber sheets, carbon fiber sheets and plates, and to propose the reasonable strengthening method for the deteriorated R.C. deep beams. Results show that the most significant differences in behavior of reinforced concrete deep beams strengthened with fiber sheet and plate were mainly due to various fiber orientations and anchorage. Deep beams diagonally strengthened with carbon fibers show better performance compared with those of vertically, horizontally strengthened specimens and produce the increase in the shear resistance through the redistribution of internal forces after the initial cracks occur. However, strengthened deep beams without anchorages might show unreasonable, brittle peeling-off failure of fiber reinforcements.
Response Analysis of Deep Ocean Risers to Vortex-Shedding by Numerical Analysis
Park, Han-Il ; Cho, Hyo-Je ; Jung, Dong-Ho ;
Journal of Ocean Engineering and Technology, volume 13, issue 3B, 1999, Pages 65~72
A deep-ocean mining riser pipe is subjected to floating vessel motion as well as environmental forces arising from currents and waves. The dynamic analysis is carried out for a deep-ocean mining riser pipe by using a finite element method. The vortex shedding which excites risers in a direction perpendicular to the flow and induces transverse response is considered. It is demonstrated that transverse displacements due to vortex shedding is greatly increased in lock-in regions. The result of this study is compared with other results having good agreements.
Experimental Study on the On-line Monitoring of Offshore Structures Using Acoustic Emission Technology
Won, Soon-Ho ; Cho, Kyung-Shik ;
Journal of Ocean Engineering and Technology, volume 13, issue 3B, 1999, Pages 73~82
In this research, an experimental study is presented to check the possibilities of offshore structures monitoring using AE techniques. The underwater transducer and preamplifier are fabricated. And, it is proved that this unit can be used for the detection of AE in offshore structures. Wave propagation studies have shown that supplementary attenuations due to seawater are significantly reducing the detection range of the sensors. It excludes the possibility of offshore structures monitoring with a small number of sensors. We conclude that AE waves would be correctly detected for a path of about 3m. Tubular joints have been tested in air and underwater using simulated elastic wave. Ability of AE techniques to detect and locate cracks early in their evolution has been demonstrated. Several parameters of AE generation have been set in evidence. It has also been shown that crack development goes with an increase of AE parameter. Conclusively, it is shown that AE techniques can provide practical alternatives to present methods being used for inspection of deep-water offshore structures undergoing structural degradation due to fatigue crack growth.
Active Control of Very Long and Flexible Offshore Structural Systems
Nam, Dong-Ho ;
Journal of Ocean Engineering and Technology, volume 13, issue 3B, 1999, Pages 83~90
A Study on Robustness of a Servosystem with Nonlinear Type Uncertainty (I) - A Synthesis of 2DOF Servosystem
Kim, Young-Bok ;
Journal of Ocean Engineering and Technology, volume 13, issue 3B, 1999, Pages 91~98
In order to reject the steady-state tracking error, it is common to introduce integral compensators in servosystems for constant reference signals. However, if the mathematical model of the plant is exact and no disturbance input exists, the integral compensation is not necessary. From this point of view, a two-degree-of-freedom(2DOF) servosystem has been proposed, in which the integral compensation is effective only when there is a modeling error or a disturbance input. The present paper considers a synthesis problems of this 32DOF servosystem with direct transfer term in the system representation. And, a method how we may obtain a gain such that desirable transient response is achieved, is proposed in the presence of the modelling error and disturbance input.
A Study on Robustness of a Two-Degree-of-Freedom Servosystem with Nonlinear Type Uncertainty(II) - Rubust Stability Condition
Kim, Young-Bok ;
Journal of Ocean Engineering and Technology, volume 13, issue 3B, 1999, Pages 99~105
In order to reject the steady-state tracking error, it is common to introduce integral compensators in servosystems for constant reference signals. However, if the mathematical model of the plant is exact and no disturbance input exists, the integral compensation is not necessary. From this point of view, a two-degree-of-freedom(2DOF) servosystem has been proposed, in which the integral compensation is effective only when there is a modeling error or a disturbance input. The present paper considers a robust stability of this 2DOF servosystem with nonlinear type uncertainty in the system, and a robust stability condition for the servosystem is introduced. This result guarantees that if the plant uncertainty is in the permissible set defined by the condition, gain tuning can be carried out to suppress the influence of the plant uncertainties and disturbance inputs.
Design for Sequential Control System Using Petri Nets with Hierarchical Expression(I) - Division of Petri Nets Based on SFC
Jeong, Seok-Kwon ; Yang, Joo-Ho ;
Journal of Ocean Engineering and Technology, volume 13, issue 3B, 1999, Pages 106~115
Modeling a discrete event system such as a sequential control system is difficult compared with a continuous system. Petri nets have been introduced as an analyzing and design tool for the discrete systems. One of the problems in its applications is that the model can not be analyzed easily in the case of large scale or complicated systems because of increase of the number of components of the system. To overcome this problem, some methods for dividing or reducing Petri nets have been suggested. In this paper, an approach for a hierarchical expression of Petri nets based on Sequential Function Chart(SFC) is proposed. A measuring tank system will be described as a typical kind of discrete systems. The system is modeled by sub Petri nets based on SFC in order to analyze and visualize efficiently about the dynamic behaviors of the system. Some numerical simulations using state equations are performed to prove the validity of the proposed method.
A Feasibility Study on the Economic Aspect of Sea Transportation System between Inchon and Youngjong Island
Chun, Jae-Woo ; Lee, Seung-Hee ;
Journal of Ocean Engineering and Technology, volume 13, issue 3B, 1999, Pages 116~126
The purpose of this study is to analyze the economic aspect of sea transportation system between Inchon and Youngjong island in which Inchon international airport is being constructed. Total demand of sea transportation arising from in the airport and Yongyu Muwi leisure complex was estimated. To select optimum transportation route, environmental conditions in and around Inchon harbour and Youngjong island including the change of water depth by tide current, fog, rain, wind adn typhoon, ets., were investigated. The preliminary consideration on ships (size, velocity, transport capacity, price), routes, operational modes, terminals and berthing facilities were carried out. The transportation cost per passenger by sea transportation system was estimated to compare with that of land transportation system. It was found that sea transportation system proposed is competitive to the transportation system.