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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society of Marine Engineering
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Journal DOI :
Korean Society of Marine Engineers
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Volume & Issues
Volume 33, Issue 8 - Nov 2009
Volume 33, Issue 7 - Nov 2009
Volume 33, Issue 6 - Sep 2009
Volume 33, Issue 5 - Jul 2009
Volume 33, Issue 4 - May 2009
Volume 33, Issue 3 - May 2009
Volume 33, Issue 2 - Mar 2009
Volume 33, Issue 1 - Jan 2009
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Numerical Investigation of Thermo-Fluid Flow for Improvement of Micro-Dilution Chamber on Particulate Deposition
Kim, Sung-Hoon ; Lee, Dong-Ryul ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 5, 2009, Pages 637~645
DOI : 10.5916/jkosme.2009.33.5.637
The main purpose of this study lies on the improvement of micro dilution tunnel based on the typical porous tube type chamber. The characteristics of flow and temperature fields for steady state has been obtained by numerical analysis using FLUENT. Three different geometrical variations of the porous tube; a) increase of thickness at center, b) step increase of thickness at center and downstream, c) tapered increase of thickness, have been proposed. Accordingly results are obtained and compared in terms of penetration velocity and velocity ratio to therrmophoretic velocity for improvement against particulate deposition inside the tube. The penetration velocity and velocity ratio distributions in the upstream portion and portion of impinging of dilution air are apparently shown to be improved for the case of the step and tapered change of porous tube. The tapered change of tube thickness addition are shown to be the most effective among three geometrical changes. In addition, the considerable improvement against deposition are shown that its thickness should be at least 2mm.
System Performance for Length and Diameter of Capillary Tube using R-1270
Lee, Ho-Saeng ; Kim, Hyun-Woo ; Choi, Won-Jae ; Yoon, Jung-In ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 5, 2009, Pages 646~652
DOI : 10.5916/jkosme.2009.33.5.646
Experimental results for performance characteristics of HCs refrigerant R-1270 and HCFC refrigerant R-22 during refrigeration system using capillary tube are presented. The system consists of compressor, condenser, capillary tube, evaporator and peripheral devices. Length and diameter of capillary tube are varied for this investigation. The refrigerant mass flow increased as the diameter of capillary tube increased and the length of capillary tube decreased. A refrigeration capacity and compressor work of R-1270 in same length and diameter of capillary tube showed the higher values than those of R-22. A coefficient of performance showed the highest value when the length and diameter of capillary tube are 105 cm and 1.8 mm in this experimental conditions.
A Study on the Acoustic Transmission Characteristics of Polygon Accumulator
Seo, Won-Sik ; Kong, Byung-O ; Kim, Young-Ho ; Nam, Kyeong-Hun ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 5, 2009, Pages 653~661
DOI : 10.5916/jkosme.2009.33.5.653
In order to reduce the noise and oscillation, it is consider a matter in all aspects about the noise stem from accumulator and the characteristic of transmission, Transformation of outside shape has change of noise occurrence at transmission process. Therefore, performed sound numerical analysis and conducted an experiment to examine the birthplace of accumulator's external shape change. In a sound numerical analysis, we can fond out transmission loss between inlet and outlet's sound pressure. In an experiment, we can make out transmission loss by sound wave separation theory through drawing sound pressure inlet and outlet.
Development of an In-Pipe Inspection and Cleaning Robot
Choi, Hyeung-Sik ; Na, Won-Hyun ; Kang, Dong-Wan ; Kang, Hyung-Suk ; Jeon, Ji-Gwang ; Kim, Hyun-Sik ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 5, 2009, Pages 662~671
DOI : 10.5916/jkosme.2009.33.5.662
In this paper, a robot was developed for in-pipe cleaning and inspecting a large number of circular in-pipes of sea plants, ships, and buildings. A pressure generation mechanism was devised to inspect circular in-pipes with different diameters and to move up and down slant or perpendicular slopes in-pipes. For inspection of the dark inner side of the pipe, a light system using LED which dissipats small electricity was developed. Also, a design method was analyzed to decide the capacity of driving motor for the robot when the mass and maximum velocity of the robot are identified. The robot developed based on the design specification, was tested to verify the performance of the pressure generation mechanism. In addition, a control system was developed for the test.
Low Speed Rolling Bearing Fault Detection Using AE Signal Analyzed By Envelop Analysis Added DWT
Kim, Byeong-Su ; Kim, Won-Cheol ; Gu, Dong-Sik ; Kim, Jae-Gu ; Choi, Byeong-Keun ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 5, 2009, Pages 672~678
DOI : 10.5916/jkosme.2009.33.5.672
Acoustic Emission (AE) technique is a non-destructive testing method and widely used for the early detection of faults in rotating machines in these days, because the sensitivity of AE transducers is higher than normal accelerometers. So it can detect low energy vibration signals. The faults in the rotating machines are generally occurred at bearings and gearboxes which are the principal parts of the machines. It was studied to detect the bearing faults by envelop analysis in several decade years. And the researches showed that AE had a possibility of the application in condition monitoring system(CMS) using the envelope analysis for the rolling bearing. And peak ratio (PR) was developed for expression of the bearing condition in condition monitoring system using AE. Noise level is needed to reduce to take exact PR value because the PR is calculated from total root mean square (RMS) and the harmonics peak levels of the defect frequencies of the bearing. Therefore, in this paper, the discrete wavelet transform (DWT) was added in the envelope analysis to reduce the noise level in the AE signals. And then, the PR was calculated and compared with general envelope analysis result and the result of envelope analysis added the DWT. In the experiment result about inner fault of bearing, defect frequency was difficult to find about only envelop analysis. But it's easy to find defect frequency after wavelet transform. Therefore, Envelop analysis added wavelet transform was useful method for early detection of default in signal process.
Flow Field Analysis of Smoke in a Rectangular Tunnel
Lee, Yong-Ho ; Park, Sang-Kyoo ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 5, 2009, Pages 679~685
DOI : 10.5916/jkosme.2009.33.5.679
In order to simulate a smoke or poisonous gas emergency in a rectangular tunnel and to investigate a better way to exhaust the smoke, the characteristics of smoke flow have been analyzed using flow field data acquired by Particle Image Velocimetry(PIV). Olive oil has been used as tracer particles with the kinematic viscosity of air,
. The investigation has done in the range of Reynolds number of 1600 to 5333 due to the inlet velocities of 0.3 m/s to 1 m/s respectively. The average velocity vector and instantaneous kinematic energy fields with respect to the three different Reynolds numbers are comparatively discussed by the Flow Manager. In general, the smoke flow becomes more disorderly and turbulent with the increase of Reynolds number. Kinematic energy in the measured region increases with the increase of Reynolds number while decreasing at the leeward direction about the outlet region.
Flow Analysis in the Tip Clearance of Axial Flow Rotor Using Finite-Element Large-Eddy Simulation Method
Lee, Myeong-Ho ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 5, 2009, Pages 686~695
DOI : 10.5916/jkosme.2009.33.5.686
Flow characteristics in linear axial cascade have been studied using large eddy simulation(LES) based on finite element method(FEM) to investigate details of the leakage flow in the tip clearance of axial flow rotor. STAR-CD(FVM) and PAT-Flow(FEM) have been adopted to solve the Navier-Stokes equations for the simulation of the unsteady turbulent flow. Numerical results from the present study have been compared with the existing experimental results to investigate a tip clearance effect on velocity profile and static pressure distribution on blade surface at various spanwise positions. Both simulation results agree well with the experimental data. However, it has been shown that the results of finite-element large-eddy simulation agree better with experimental data than
turbulent model based on finite volume method regarding the tip vortex geometry and static pressure distribution at the center of the tip vortex core. As a result of this study, it is shown that finite-element large-eddy simulation method can predict more exactly on the tip leakage vortex flow and behind flow field.
A Numerical Study on the Flow Characteristics through an Industrial Safety Relief Valve
Kang, Sang-Mo ; Lee, Bong-Hee ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 5, 2009, Pages 696~704
DOI : 10.5916/jkosme.2009.33.5.696
In this paper, the flow characteristics through an industrial safety relief valve used to protect the crankcase room in a large-sized marine engine have been numerically investigated using the moving-mesh strategy. With the room pressure higher than the cracking one, the spring-loaded disc becomes open and then the air in the room blows off into the atmosphere, resulting in the reduction of the room pressure and then the shutoff of the disc. Numerical simulations are performed on the compressible air flow through the relief valve (
) with the initial room pressure (0.11 bar or 0.12bar) higher than the cracking one (0.1 bar). The numerical method has been validated by comparing the results with the empirical ones. Results show that the disc motion and flow characteristics can be successfully simulated using the moving-mesh strategy and depend strongly on the spring stiffness and the flow passage shape. With increasing spring stiffness, the maximum disc displacement decreases and thus the total disc-opening time also decreases. In addition, the flow passage shape makes a significant effect on the velocity and direction of the flow.
Development of a Floating Buoy for Monitoring Ocean Environments
Yu, Yung-Ho ; Gang, Yong-Soo ; Lee, Won-Boo ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 5, 2009, Pages 705~712
DOI : 10.5916/jkosme.2009.33.5.705
The state changes of ocean covered over 70% of earth surface are one of the greatest factor of weather catastrophe. Recently weather extraordinary events are followed by steep increase of sea water temperature and scientists in various fields are studying and warning the weather changes. In this paper, floating buoy is developed to monitor ocean environments via Orbcomm satellite and a method is proposed to increase measurement accuracy of sea water temperature with common low price temperature sensor. Experimental results are presented to illustrate the usability and effectiveness of the developed system. A web-based real time monitoring system is built to monitor ocean environmental information such as sea and air temperature, salinity according to the position of buoy through the internet for user convenience.
Precision Control of Belt Drives using Feed Forward Compensator under Acceleration and Velocity Constraints
Kwon, Sei-Hyun ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 5, 2009, Pages 713~720
DOI : 10.5916/jkosme.2009.33.5.713
Numerous applications of position controlling devices using servoing technique and transmission of energy through belt drives are practiced in the industry. Belt drive is a simple, lightweight, low cost power transmission system. Belt drives provide freedom to position the motor relative to the load and this phenomenon enables reduction of the robot arm inertia. It also facilitates quick response when employed in robotics. In this paper, precision positioning of a belt driven mechanism using a feed-forward compensator under maximum acceleration and velocity constraints is proposed. The proposed method plans the desired trajectory and modifies it to compensate delay dynamics and vibration. Being an offline method, the proposed method could be easily and effectively adopted to the existing systems without any modification of the hardware setup. The effectiveness of the proposed method is demonstrated through computer simulation and experimental results.
PID Control of Unstable Processes with Time Delay
Lee, Soo-Lyong ; Lee, Yun-Hyung ; Ahn, Jong-Kap ; Son, Jung-Ki ; Ryu, Ki-Tak ; So, Myung-Ok ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 5, 2009, Pages 721~728
DOI : 10.5916/jkosme.2009.33.5.721
PID control is widely used to control stable processes, however, PID control for unstable processes is less common. In this paper, systematic tuning methods are derived to tune the PID controller for unstable FOPTD(Forst Order Plus Time Delay) processes. The proposed PID controllers for set-point tracking and disturbance rejection problem are tuned based on minimizing the performance indexes (IAE, ISE, ITAE) using a real-coded genetic algorithm. Simulation example is given to illustrate the set-point tracking and disturbance rejection performance of the proposed method.
Experiment Based Dynamic Analysis for High Accuracy Control of Feed System
Kim, Shung-Hyun ; Jeong, Jae-Hyun ; Kim, Jae-Hyun ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 5, 2009, Pages 729~737
DOI : 10.5916/jkosme.2009.33.5.729
This paper introduces the machine tools feed system, which can be optimized the control's performance through simulation and the adjustment of the mechanical components. One method simulates the frequency response of the speed-loop with the design value using the MATLAB application, so that all of the interpolation axis can be equal to the response bandwidth, resulting in a high accuracy rate. The other method sees the mechanical component being adjusted by analyzing the results of various experiments. Lastly, this client's program is able to change the parameters that are related to the FFD, as well as the parameters in the friction compensation of the OPEN-CNC.
The Study about Channel code to Overcome Multipath of Underwater Channel
Kim, Nam-Soo ; Kim, Min-Hyuk ; Park, Tae-Doo ; Kim, Chul-Seung ; Jung, Ji-Won ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 5, 2009, Pages 738~745
DOI : 10.5916/jkosme.2009.33.5.738
Underwater acoustic communication has multipath error because of reflection by sea-level and sea-bottom. The multipath of underwater channel causes receive signal to make error floor. In this paper, we propose the underwater communication system using various channel coding schemes such as RS coding, convolutional code, turbo code and concatenated code for overcoming the multipath effect in underwater channel. As shown in simulation results, characteristic of multipath error is similar to that of random error. So interleaver has not effect on error correcting. For correcting of error floor by multipath, it is necessary to use strong channel codes like turbo code. Turbo code is one of the iterative codes. And the performance of concatenated codes including RS code has better performance than using singular channel codes.
Development of Embedded Vessel Monitoring System Using NMEA2000
Lee, Chang-Ui ; Kim, Dal-Yong ; Yu, Yung-Ho ; Shin, Ok-Keun ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 5, 2009, Pages 746~755
DOI : 10.5916/jkosme.2009.33.5.746
Recently, NMEA2000 became the de facto standard of the communication protocol for the instrument level network in vessels, and it is anticipated that most of the vessels will be equipped with the sensors and actuators based on this protocol. The conventional serial communication specifications such as RS-232, RS-485, or even NMEA0183 are single-talker/multiple-listener and interconnection among multiple sensors and/or actuators usually results in a bundle of wires. On the other hand, NMEA2000 is a true bus type(multiple-talker/multiple-listener) protocol and theoretically up to 256 instruments can be hot-plugged. With the advent of the protocol, it is necessary to consider a new type of monitoring system for the instruments in vessels: In most traditional serial communication environments, a dedicated monitor or user interface was necessary for each sensor or actuator as it was simply not easy to collect data in a single place. With NMEA2000, the collection of various types of information is simple. An embedded system can be employed to combine, to arrange and to display informations from various types of devices. Assuming that the actuators and sensors on a vessel are interconnected by NMEA2000 standard, we devise a tentative interactive vessel monitoring system in which the following 4 kinds of informations are collected and delivered: the navigation, engine, weather and tanks informations.
X-band Voltage Controlled Oscillator using Varactor Diode
Park, Dong-Kook ; Yun, Na-Ra ; Choi, Yean-Ji ; Kim, Yea-Ji ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 5, 2009, Pages 756~761
DOI : 10.5916/jkosme.2009.33.5.756
In this paper, a X band voltage controlled oscillator is proposed. The oscillator uses a transistor as an oscillating element and its oscillating frequencies are controlled by the tuning voltage of varactor diode. Using the circuit simulation tools, the matching circuits between the transistor and varactor diode, its input and output matching circuits, and a feedback circuits are designed. The measured results of the fabricated oscillator show that its oscillation frequencies are from 10.50GHz to 10.88GHz according to the turning voltages of 1V to 18V, its output power levels are about 4.3dBm, and its phase noise is around -43.5dBc/Hz at 100kHz offset frequency of 10.5GHz.
A Study on the Development of Ship Building for the Wooden Canoe by Piling-up Laminated Wooden Plates Kit  - A Design for canoe hull and laminating wooden plates for piling-up kit -
Kim, Heui-Jung ; Kim, Shung-Hyun ; Jeong, Jae-Hyun ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 5, 2009, Pages 762~769
DOI : 10.5916/jkosme.2009.33.5.762
A canoe is one of the most popular boats in leisure on the water. Generally canoe has been built by good wooden strips. And canoe built by FRP is used for business recently. But by the users' demands for good quality and the restriction to environmental pollution the wooden canoes are required for personal and canoe building business. The modern wooden canoes were built by the strip construction method are used typically. However it is not suitable for the mass productivity requires effective resource operations and managements of men, materials, times, and price. On this paper the new construction method, called the piling-up laminated construction method, is studied to building a canoe using the piling-up with the laminated wooden plates gives more productivity than the others. First a canoe with various curved surfaces is designed from 3D design system. And the hull of canoe model is divided horizontally to generating the laminated plates that will be converting real wooden plates available from the market and will be routed by the manufacturing machine. After the simulating and analyzing of piling-up with the laminated plates, the canoe is building with less times, less men, less resources, and lower price than other method, avoid of the requirements of additional building tools. On the next paper the constructing of a real canoe using the manufactured wooden plates will be studied.
An Experimental Study on the Performance of PEMFC Stack Depending on Operating Conditions
Lee, Ji-Hong ; Lee, Myeong-Yong ; Lee, Sang-Seok ; Nam, Il-Sang ; Lee, Do-Hyung ;
Journal of the Korean Society of Marine Engineering, volume 33, issue 5, 2009, Pages 770~777
DOI : 10.5916/jkosme.2009.33.5.770
The energy depletion and the environmental pollution like global warming are worldwide issues. For correcting these problems there are many studies on new-renewable energy in Korea. A kind of new-renewable energy, PEMFC(Proton Exchange Membrane Fuel Cell) is a low temperature fuell cell and there are some cases of small craft or submarine adopted PEMFC system in maritime. PEMFC's performance is affected the operating conditions. Finding optimum operating conditions must be performed before adopting PEMFC to system. So in this study, we experiment about various operating conditions to apply 150W PEMFC stack for a model boat. And through the results, we find optimum operating conditions and study an effect of operating conditions to PEMFC.