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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 32, Issue 8 - Nov 2008
Volume 32, Issue 7 - Nov 2008
Volume 32, Issue 6 - Sep 2008
Volume 32, Issue 5 - Jul 2008
Volume 32, Issue 4 - May 2008
Volume 32, Issue 3 - May 2008
Volume 32, Issue 2 - Mar 2008
Volume 32, Issue 1 - Jan 2008
Selecting the target year
A Numerical Study on Heat Transfer and Friction in Rectangular Channel with Inclined Perforated Baffles
Putra, Ary Bachtiar Krishna ; Ahn, Soo-Whan ; Kang, Ho-Keun ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 7, 2008, Pages 1003~1012
DOI : 10.5916/jkosme.2008.32.7.1003
A three dimensional numerical study has been applied to predict the turbulent fluid flow and heat transfer characteristics for the rectangular channel with different types of baffles. Four different types of the baffles are used. The inclined baffles have the width of 19.8 cm, the square diamond type hole having one side length of 2.55 cm, and the inclination angle of
. Reynolds number is varied between 23,000 and 57,000. The SST k-
turbulence model is used in the present numerical study. The validity of the numerical results is examined with the experimental data. The numerical results of the flow field depict that the flow patterns around the different baffle type are entirely different and it significantly affects the local heat transfer characteristics. The heat transfer and friction factor depend significantly on the number of baffle holes. It is found that the heat transfer enhancement of baffle type II (3 hole baffle) has the best values.
The Effect of Fuel Injection Timing on the Combustion and Emission Characteristics of a Natural Gas Fueled Engine at Part Loads
Cho, Haeng-Muk ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 7, 2008, Pages 1013~1018
DOI : 10.5916/jkosme.2008.32.7.1013
For a sequential port fuel injection natural gas engine, its combustion and emission characteristics at low loads are crucial to meet light duty vehicle emission regulations. Fuel injection timing is an important parameter related to the mixture formation in the cylinder. Its effect on the combustion and emission characteristics of a natural gas engine were investigated at 0.2 MPa brake mean effective pressure (BMEP)/2000 rpm and 0.26 MPa BMEP/1500 rpm. The results show that early fuel injection timing is beneficial to the reduction of the coefficient of variation (COV) of indicated mean effective pressure (IMEP) under lean burn conditions and to extending the lean burn limits at the given loads. When relative air/fuel ratio is over 1.3, fuel injection timing has a relatively large effect on engine.out emissions. The levels of NOx emissions are more sensitive to the fuel injection timing at 0.26 MPa BMEP/1500 rpm. An early fuel injection timing under lean burn conditions can be used to control engine out NOx emissions.
Visualization of Diesel and GTL Spray Combustion and Soot Formation in a Rapid Charging Combustion Vessel with Shadowgraph Method
Kim, Ki-Seong ; Azimov, Ulugbek ; Lee, Yong-Ho ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 7, 2008, Pages 1019~1029
DOI : 10.5916/jkosme.2008.32.7.1019
In this study, visual investigation of sprays and flames has been performed and soot formation in Diesel and GTL fuels has been compared in a specially designed Rapid Charging Combustion Vessel (RCCV) under various ambient gas
concentrations and two injection pressures. It has been concluded that soot in the mixing-controlled combustion of Diesel and GTL fuels has similar tendency to be formed in the leading portion of the jet boundaries. Auto-ignition delay for GTL fuel is shorter than that for diesel fuel. The temporal and special variation of soot concentration in the diesel flame jets at various
concentrations was correlated with the heat release rate. Soot concentration appears in the regions when diffusion combustion starts, and its concentration reaches maximum at the peak of heat release curve and then decreases due to oxidation. Visualization by shadowgraph method showed that soot decreases with lower
concentration, and higher injection pressure.
Emissions of Marine Heavy Fuel Oil in the Spray Flame
An, Suk-Heon ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 7, 2008, Pages 1030~1035
DOI : 10.5916/jkosme.2008.32.7.1030
Recently, the International Maritime Organization makes an effort for an effective solution against the emissions from shipping in the international maritime industry. The objective of the study was to quantify the exhaust emissions of marine heavy fuel oil in the combustion process of the spray flame. An experiment was performed to measure CO,
, DS, SOF and the other components with the flame temperature. The sampling probe was directly set up in the flame fields at each position of 103, 324, 545, 766 and 987mm vertically apart from the fuel-injected nozzle in the burner furnace. From the results of the study, it was estimated that approximately 270ppm of oxides of nitrogen (NOx),
of sulfur dioxide (
), 8ppm of nitrous oxide (
of particulate matter (PM) divided with dry soot (DS) and soluble organic fraction (SOF) and
of sulfuric acid. With respect to further development of this work, the emission quantification could also be applied to assessing emission reduction from the international shipping.
The Visualization of the Flow Field through Ship's Propulsion Mechanism of Weis-Fogh Type using the PIV
Ro, Ki-Deok ; Kim, Kwang-Seok ; Kim, Si-Young ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 7, 2008, Pages 1036~1043
DOI : 10.5916/jkosme.2008.32.7.1036
The Flow fields of a ship's propulsion mechanism of Weis-Fogh type were investigated by the PIV. Velocity vectors and velocity profiles around the operating and stationary wings were observed at opening angles of
, velocity ratios of V/U=
and Reynolds number of Re=
. As the results the fluid between wing and wall was inhaled in the opening stage and was jet in the closing stage. The wing in the translating stage accelerated the fluid in the channel. And the flow fields of this propulsion mechanism were unsteady and complex, but those were clarified by flow visualization using the PIV.
Internal Flow Analysis of a Tubular-type Small Hydroturbine by Runner Vane Angle
Nam, Sang-Hyun ; Kim, You-Taek ; Choi, Young-Do ; Lee, Young-Ho ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 7, 2008, Pages 1044~1050
DOI : 10.5916/jkosme.2008.32.7.1044
Most of developed countries, the consumption of fossil fuels has been serious problems that cause serious environment pollution like acid rain, global warming. Also, we have faced that limitation fossil fuels will be exhausted. Currently, small hydropower attracts attention because of its small, clean, renewable, and abundant energy resources to develop. By using a small hydropower generator of which main concept is based on using the different water pressure levels in pipe lines, energy which was initially wasted by use of a reducing valve at the end of the pipeline, is collected by turbine in the hydropower generator. A propeller shaped hydroturbine has been used in order to use this renewable pressure energy. In this study, in order to acquire basic design data of tubular type hydraulic turbine, output power, head, efficiency characteristics due to the flow coefficient are examined in detail. Tubular-turbine among small hydraulic power generation can be used at low-head. The purpose of this study is to research turbine's efficiency due to runner vane angle using CFD analysis.
A Study on the Correlation Analysis of the Present Status of Turbo Pumps Installed in Ships
Lee, Sang-Il ; Kim, You-Taek ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 7, 2008, Pages 1051~1060
DOI : 10.5916/jkosme.2008.32.7.1051
Now days, various types of ships are operated to transport both cargo and passengers all around the world. Most of the important auxiliary machinery installed in those ships is fluid machinery such as pumps, compressors, and fans. A large percentage of fluid machinery is pumps which are classified as turbo and positive displacement pumps. This paper analyzes only turbo pumps out of the two types. This thesis has two aims: (a) to analyze the present status of pumps installed in merchant and training ships and (b) to find the correlation among sea going pump kW, port pump kW, GE kW, ME MCR, number of pumps, ME kgf, pump kgf. Based on the ship's type, my paper seeks to find special characteristics as a result of analyzing head, flow rate, and kW. Moreover this paper analyzes and compares number of pumps, rpm of pumps, pump kW/ME MCR and pump kW/GE kW under the conditions of seagoing and berthing according to the ship's type. In conclusion, (1) For the exact comparison, information on the head, kW, flow rate, number of pumps by ship's type, the pump installation status of the Merchant Ships and Training Ships were tabulated and compared in this paper. (2) In order to qualify one ship as the delegate ship, several methods were used. The result of the examination indicates that the chosen ships could be justified as a suitable representation of ships of their own type. (3) The correlation of several values(total pump kW, port pump kW, GE kW, seagoing pump kW, pump weight, ME weight, ME MCR, number of pumps and ME kW) could be obtained.
A New Direct Torque Control Method of Induction Motor for Torque Ripple Reduction
Kim, Deok-Ki ; Kim, Jong-Su ; Kim, Sung-Hwan ; Kim, Hyun-Soo ; Kim, Won-Ouk ; Yoon, Kyoung-Kuk ; Oh, Sae-Gin ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 7, 2008, Pages 1061~1067
DOI : 10.5916/jkosme.2008.32.7.1061
Direct Torque Control[DTC] and Vector Control are the two schemes developed for high performance induction motor drives. DTC based induction motors are being increasingly used in various industrial applications. DTC offers fast torque response and better speed control with lesser hardware and processing costs as compared to vector controlled drives. However, conventional DTC suffers from high torque ripple, current harmonics and low performance during torque transients. In this paper a new Direct Torque Control[DTC] method of induction motor is presented. In comparison with the conventional DTC method, the PWM technique is applied to proposed control method. In this method, decoupling mechanism is not required and the torque, the flux magnitude are under control using PI controllers and generating the voltage command for inverter control. Therefore torque and speed ripple could be reduced in comparison with the conventional switching table DTC.
A Tilt and Heading Estimation System for ROVs using Kalman Filters
Ha, Yun-Su ; Ngo, Thanh-Hoan ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 7, 2008, Pages 1068~1079
DOI : 10.5916/jkosme.2008.32.7.1068
Tilt and heading angles information of a remotely operated vehicle (ROV) are very important in underwater navigation. This paper presents a low.cost tilt and heading estimation system. Three single.axis rate gyros, a tri-axis accelerometer, and a tri-axis magnetometer are used. Output signals coming from these sensors are fused by two Kalman filters. The first Kalman filter is used to estimate roll and pitch angles and the other is for heading angle estimation. By using this method, we have obtained tilt (roll and pitch angles) and heading information which are reliable over long period of time. Results from experiments have shown the performance of the presented system.
A Study on Diesel Engine NOx and Soot Emission Characteristics using Different Fuel Oils
Nam, Jeong-Gil ; Kang, Dae-Sun ;
Journal of the Korean Society of Marine Engineering, volume 32, issue 7, 2008, Pages 1080~1088
DOI : 10.5916/jkosme.2008.32.7.1080
This paper addresses some concerns faced by the shipping industry nowadays. Initially, the environmental issues were resolved and stricter regulations are now being implemented with regards to the exhaust gas, specifically nitrogen oxides (NOx) and sulfur oxides (SOx), emitted from ships. Secondly, with the increasing and unstable cost of fuel oils in the world market, it has become almost a necessity to explore on a new alternative fuel. Hence, this study was conducted. An experiment was carried-out on a fishing survey vessel with the main engine (M/E) and generator engine (G/E) operated on expensive marine gas oil (MGO). During the experiment, two pre-refinery systems were installed and different fuel oil samples were employed for the M/E and the G/E. Furthermore, the NOx emission and soot concentration were monitored and verified. The results confirmed the compatibility of some fuel oil types to the engines and meeting the emission standards. MDO, MF15 and Bunker A can be used in place of MGO for the engines(M/E, G/E).