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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 27, Issue 7 - Nov 2003
Volume 27, Issue 6 - Sep 2003
Volume 27, Issue 5 - Jul 2003
Volume 27, Issue 4 - Jul 2003
Volume 27, Issue 3 - May 2003
Volume 27, Issue 2 - Mar 2003
Volume 27, Issue 1 - Jan 2003
Selecting the target year
Technical Trend of Geothermal Heat Pump
Journal of the Korean Society of Marine Engineering, volume 27, issue 7, 2003, Pages 811~816
A Design and Implementation of a Windows Visual System for the Monitoring of Red Tide on the Internet
Journal of the Korean Society of Marine Engineering, volume 27, issue 7, 2003, Pages 817~825
The amount of damage suffered from the red tide occurring at the near shore is increasing rapidly. The Windows visual system discussed in this paper is developed in order to help minimize the damage. The system is focused on the monitoring the coastal environment. and forecasting the red tide occurrence. Although several similar systems are now existing. most of them are based on the web application. which cause the large response time. limited presentation ability of data. and inability of data storing at client side. The Windows visual system described in this paper operates on the Internet to get the ubiquitous access. One of three components of the Windows visual system. client system is developed as a Windows application in order to overcome the weak points of the previous systems. The gathering. analysis, and monitoring of data can be done at real time using the Windows visual system.
A Study on Surface Tension Measurement for the Water through Electro-Magnetic Field
Journal of the Korean Society of Marine Engineering, volume 27, issue 7, 2003, Pages 826~831
The purpose of this study was to measure the surface tension of hard water through electro-magnetic field for investigating the effect of electro-magnetic water treatment. The maximum reduction of surface tension was 8% comparing to the no treatment case. When the flow velocity through the permanent magnetic device (PMD) was 6.3 m/s, sample of hard water had the minimum surface tension.
Investigation of NOx Reduction Ratio on SCR System for a Marine Diesel Engine
Journal of the Korean Society of Marine Engineering, volume 27, issue 7, 2003, Pages 832~838
IMO NOx levels are generally possible to meet by means of primary on-engine measures. Nevertheless further significant follow-on reductions are likely to require a secondary after-treatment technique. SCR system is currently the only available technology proven at full scale to meet the 90% NOx reduction levels. Accordingly, maybe the use of an SCR system on board ship provides the solution to minimize this primary pollutant without increasing fuel consumption. In order to develop a practical SCR system for marine application on board ship, a primary SCR system using urea was made. The SCR system was set up on the ship. employed a two-stroke diesel engine as a main propulsion. which is a training ship in KMU (Korea Maritime Univ.). The purpose of this paper is to report the results about the basic effects of the above system parameters which is investigated from practical application through its trial use. The degree of NOx removal depends on some parameters. such as the amount of urea solution added, space velocity. reaction gas temperature and activity of catalyst. The preliminary results from trial run are presented.
Thermal Analysis of Double-tube Triple-flow LNG Vaporization System
Journal of the Korean Society of Marine Engineering, volume 27, issue 7, 2003, Pages 839~844
As sea water is being used as only heat source of LNG open rack vaporizer, serious problem has been risen in LNG terminal by the lack of heating energy source for LNG vaporization due to the temperature drop of sea water in winter. In this paper the new double-tube triple-flow(TRIDEX) vaporizer was suggested to solve the problem and the system was thermally analysed. LPG(liquefied petroleum gas) and sea water were introduced as the heat sources for LNG TRIDEX vaporizer. The flow patterns of TRIDEX vaporizer are as follows: LNG flow in the annular space, PG(petroleum gas) flow in the inner tube, and sea water flow in the outside of the double pipe. The overall LNG vaporization system was consisted of TRIDEX vaporizer, LPG vaporizer and PG heater. LPG in TRIDEX was directly dispersed in the sea water desalination unit, so that LPG turns to be gas phase for the reuse in TRIDEX vaporizer. New TRIDEX vaporizer system for LNG evaporation was analysed as much more effective than the present single tube one in the case of colder temperature of sea water in winter.
A Study on the Pollutants Reduction of Venturi Type After-burner by oxygen enrichment and Induced Air
Journal of the Korean Society of Marine Engineering, volume 27, issue 7, 2003, Pages 845~851
The purpose of this experimental study is to investigate the quantitative pollutants reduction by oxygen enrichment and induced air effect in venturi type after-burner. For this purpose, CO,
. and HC concentrations were measured before and after the after-burner by changing the Oxygen flow rate and area ratio which is defined as the ratio of air inducing area divided by total area. As results of this study, when the area ratio were increased, the emission reduction effect was increased even less oxygen flow rate. In that case when oxygen was injected too little, the pollutants were increased.
A Study on the Performance Improvement of a Nonlinear Fuzzy PID Controller
Journal of the Korean Society of Marine Engineering, volume 27, issue 7, 2003, Pages 852~861
In this paper, in order to improve the disadvantages of the fixed design-parameter fuzzy PID controller. a new fuzzy PID controller named a variable design-parameter fuzzy PID controller is suggested. The main characteristic of the suggested controller is to adjust design-parameters of the controller by comparing magnitudes between fuzzy controller inputs at each sampling time when controller inputs are measured. As a result. all fuzzy input partitioned spaces converge within a time-varying normalization scale. and the resultant PID control action can always be applied precisely regardless of operating input magnitudes. In order to verify the effectiveness of the suggested controller. several a computer simulations for a nonlinear system are executed and the control parameters of the variable design-parameter fuzzy PID controller are throughly analyzed.
A Study on the modeling for the control of magnetic levitation stage
Journal of the Korean Society of Marine Engineering, volume 27, issue 7, 2003, Pages 862~871
In this paper, we addressed a modeling for the magnetic levitation stage. This planar magnetic levitator employs four permanent magnet liner motors. Each motor generates vertical force for suspension against gravity, as well as horizontal force for propulsion. Therefore. this stage can generate six degrees of freedom motion by the combination of forces. We derived a mechanical dynamics equation using Lagrangian method and electromechanical dynamics equation by using Co-energy method. Based on the derived dynamics, we can analyze the stage motion that is subject to the input currents and forces.
A Study on the IR Drop in Crevice of AISI 304 Stainless Steel by Temperature Variation
Journal of the Korean Society of Marine Engineering, volume 27, issue 7, 2003, Pages 872~878
As the results of recent industrial development, many industrial plants and marine structures are exposed to severe corrosion environment than before. Especially, under the wet environment, crevice corrosion damage problems necessarily occur and encourage many interests to prevent them. In this study, the electrochemical polarization test was carried out to study characteristics of crevice corrosion for AISI 304 stainless steel in various solution temperatures. The results are as follows ; 1) as the solution temperature increased in IN
, the passive current density and critical current density were increased, whereas corrosion potential and break down potential were nearly constant, 2) as the solution temperature increased. the induced time for initiation of crevice corrosion was shortened. 3) The potential range in the crevice was -220mV/SCE to -380mV/SCE according to the distance from the crevice opening, which is lower than that of external surface of -200mV/SCE.
An Experimental Investigation of Swirl Angle in a Horizontal Round Tube by Flow Visualization Method
Tae-Hyun Chang ;
Journal of the Korean Society of Marine Engineering, volume 27, issue 7, 2003, Pages 879~888
Swirling air flow in a horizontal round tube was experimentally studied for its visualization. The present investigation deals with swirl angle, flow visualization studies and accompanying vortex core behavior by using oil smoke and a hot wire anemometer for Re = 40,000 and 50000 at X/D = 41, 59 and 71. In the swirl air flow, a vortex core was formed at high swirl intensity along the test tube. The swirl angle and the vortex core depended on the swirl intensity along the test tube. The results of swirl angles measured by flow visualization and hot wire reasonably agree with those of previous studies.
A Study on the Effect of Turbulent Combustion upon Soot Formation in Premixed Constant-Volume Propane Flames
Journal of the Korean Society of Marine Engineering, volume 27, issue 7, 2003, Pages 889~898
The soot yield is studied by a premixed propane-oxygen-inert gas combustion in a specially designed disk-type constant-volume combustion chamber to investigate the effect of turbulence on soot formation. Premixtures are simultaneously ignited by eight spark plugs located on the circumference of chamber at 45 degree intervals in order to observe the soot formation under high pressures and high temperatures. The eight flames converged compress the end gases to a high pressure. The laser schlieren and direct flame photographs for observation field with 10 mm in diameter are taken to examine into the behaviors of flame front and gas flow in laminar and turbulent combustion. The soot volume fraction in the chamber center during the final stage of combustion at the highest pressure is measured by the in situ laser extinction technique and simultaneously the corresponding burnt gas temperature by the two-color pyrometry method. It is found that the soot yield of turbulent combustion decreases in comparison with that of laminar combustion because the burnt gas temperature increases with the drop of heat loss.
A Study on the Flow Characteristics of Mixer by Impeller Types
Journal of the Korean Society of Marine Engineering, volume 27, issue 7, 2003, Pages 899~905
Mixers are used in several industrial applications where it is necessary to strongly mix reactants in a short period of time (eg. reaction injection molding, ceramics manufacturing, crystallization). However, despite their widespread use, mixing flow characteristics in these systems have not been rigorously investigated. Influence of blade shapes on the mixing time and the power consumption per unit volume in two kinds of impeller including the mixing effects are studied by PIV experiment. A series of the experiments were carried out to achieve a better mixing effect in simple baffle arrangement and tall vessel with modified impellers(two kinds of blades : pitched blade turbine and rushton turbine). Results show that periodic vortex from the mixing layer is predominant and related unsteady flow characteristics prevail over the entire region.
A Study on Flow Analysis and an Estimate of performance for HAWT by CFD
Journal of the Korean Society of Marine Engineering, volume 27, issue 7, 2003, Pages 906~913
The purpose of this 3-D numerical simulation is to evaluate the application of a commercial CFD code to predict 3-D flow and power characteristics of wind turbines. The experimental approach, which has been main method of investigation, appears to be its limits, the cost increasing with the size of the wind turbines, hence mostly limited to observing the phenomena on rotor blades. Therefore. the use of Computational Fluid Dynamics (CFD) techniques and Navier-Stokes solvers are considered a very serious contender. The flow solver CFX-TASCflow is employed in all computations in this paper. The 3-D flow separation and the wake distribution of 2 and 3 bladed Horizontal Axis Wind Turbines (HAWTs) are compared to Heuristic model and smoke-visualized experimental result by NREL(National Renewable Energy Laboratory). Simulated 3-D flow separation structure on the rotor blade is very similar to Heuristic model and the wake structure of the wind turbine is good consistent with smoke-visualized result. The calculated power of the 3 bladed rotor by CFD is compared with BEM results by TU-Delft. The CFD results of which is somewhat consist with BEM results. under an error less than 10%.
Drift Compensation Algorithm of Acceleration Sensor for Galloping Measurement System
Journal of the Korean Society of Marine Engineering, volume 27, issue 7, 2003, Pages 914~920
In this paper, we deal with two drift compensation algorithms of acceleration sensor for measuring the galloping on power transmission line. Firstly, the block diagram of galloping measurement system is given and a galloping model is presented. Secondly, two compensation algorithms, a simple compensation and a period compensation, are proposed. A simple compensation algorithm uses the drifts of velocity and distance at fixed periods, so it is useful for constant drift case. Next, a period compensation algorithm can compensate a periodic drift. This algorithm uses the previous measured data and compensated data for constant period, where the period is obtained by FFT method. Lastly, the effectiveness of proposed algorithms is verified by comparing between two algorithms in simulation, and its characteristics and the drift error bound are shown, respectively.
An Experimental Study on Temperature and Velocity Fields of the Turbulent Flows Horizontal Cylindrical Tube by Using Thermo-sensitive Liquid Crystal
Journal of the Korean Society of Marine Engineering, volume 27, issue 7, 2003, Pages 921~929
An experimental investigation was performed to study the characteristics of turbulent water flow in a horizontal circular tube by using liquid crystal. To determine some characteristics of the turbulent flow, 2D PIV technique is employed for velocity measurement and liquid crystal is used for heat transfer experiments in water. Temperature visualization was made quantitatively by calibrating the color of the liquid crystal versus temperature using various approaches (TLC technique: Thermochromic Liquid Crystal), and a neural-network algorithm was applied to the color-to-temperature calibration. This study shoud the temperature and time-mean velocity distribution for Re = 2,436, 2,500 and 2,724 along longitudinal sections and the results appear to be physically reasonable.
Sensorless Speed Control of Direct Current Motor using Current Error Compensation
Journal of the Korean Society of Marine Engineering, volume 27, issue 7, 2003, Pages 930~936
A new method of direct current motor drive, which requires neither shaft encoder nor speed estimator, is presented. The proposed scheme is based on decreasing current gap between a numerical model and an actual motor. By supplying the identical instantaneous voltage to both model and motor in the direction of reducing the current difference, the rotor approaches to the model speed, that is, reference value. The performance of direct current motor drives without speed sensor is generally poor at very low speed. However, in this system, it is possible to obtain good speed performance in the low speed range.