• Journal of the Society of Naval Architects of Korea
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• v.49 no.6
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• pp.478-483
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• 2012

The speed performances of ice sea trial on the Arctic(2010 & 2011) area were shown different results depend on the ice floe size. Penetration phenomena of level ice was not happened on medium ice floe and tore up by the impact force because the mass of medium ice floe is similar to the mass of Araon which is Korean ice breaking research vessel and did not shut up by the ice ridge or iceberg. The sea trial on the Amundsen sea was performed at the big floe which is classified by WMO(World Meteorological Organization). Three measurements of ice properties and five results of speed trial were obtained with different ice thicknesses and engine powers. To evaluate speed of level ice trial and model test results at the same ice thickness and engine power, the correction method of HSVA(Hamburg Ship Model Basin) was used. The thickness, snow effect, flexural strength and friction coefficient were corrected to compare the speed of sea trial. The analyzed speed at 1.03m thickness of big floe was 5.85 knots at 10MW power and it's 6.10 knots at 1.0m ice thickness and the same power. It's bigger than the results of level ice because big floe was also slightly tore up by the impact force of vessel based on the observation of recorded video.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.5
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• pp.525-530
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• 2013

In this study, the generator engine of training ship M/S "HAE RIM" of Kunsan National University which is being operated for 20 years was used in the experiment. The experiment was carried out under the engine speed of 1200rpm, then the load was varied 30 kW intervals from 0 to 90 kW and the injection timing was varied $2^{\circ}$CA intervals from BTDC $19^{\circ}$ to $23^{\circ}$CA. In the case of advancing fuel injection timing from BTDC $21^{\circ}$CA to $23^{\circ}$CA, specific fuel consumption is decreased by 1.37%, NOx is increased by 11.59 %, soot is decreased by 23.5 % and $SO_2$ is decreased by 2.8 %. Accoring to the analysis of effects of fuel injection timing on combustion & exhaust emissions characteristics on an old marine diesel engine, it is proved that the optimum fuel injection timing is BTDC $23^{\circ}$ which is $2^{\circ}$ faster than that of original injection timing.

• Journal of the Korea Institute of Military Science and Technology
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• v.12 no.5
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• pp.590-600
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• 2009

In the simulation of underwater vehicles such as a submarine or a torpedo, various type of simulations like an engineering level simulation for predicting the performance precisely and an engagement level simulation for examining the effectiveness of a certain tactic is required. For this reason, a tactics manager which can change the behavior of a simulation model according to external tactics is needed. In this study the tactics manager supporting a script language and engine which can represent various tactics and can help users define external input tactics for the tactic manager easily is suggested. Python and Lua which are representative among script languages have been compared and analyzed from the viewpoint of a tactic manage, and the tactic manger using the script engines of those script languages was implemented. To demonstrate the effectiveness of the tactic manager, a target motion analysis simulation of the warfare between a submarine and a surface ship.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.1044-1053
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• 2022

Time domain reflectometry (TDR) is a diagnostic technique to evaluate the physical integrity of cable and finds application in leak detection and localization of piping system. In this study, a cable-shaped leak detection sensor was proposed using the TDR technique for monitoring leakage detection of ship's engine room seawater piping system. The cable sensor was developed using a twisted pair arrangement and wound by an absorbent material. The availability and performance of the sensor for leak detection and localization were evaluated on a lab-scale pipeline set up. The developed sensor was installed onto the pipes and flanges of the lab-scale set up and various TDR waveforms were acquired and analyzed according to the dif erent variables including the number of twists and sheath thickness. The result indicated that the twisted cable sensor was able to produce clear and smooth signal as compared to the TDR sensor with a parallel arrangement. The optimal number of twist was determined to be above 10 per the unit length. The optimal diameter of sheath thickness that results in the desired sensitivity was determined to be ranging from 80% up to 120% of the diameter of the conductor. The linear regression analysis for estimation of leak localization was carried out to estimate the location of the leakage, and the result was a determination coefficient of 0.9998, indicating a positive relationship with the actual leakage point. The proposed TDR based leak detection method appears to be an effective method for monitoring leakage of ship's seawater piping system.

• Journal of Power System Engineering
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• v.18 no.6
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• pp.180-185
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• 2014

Due to the larger and high-speed vessels recently constructed, output and speed of the engines for propulsion or power generation is increasing. These high-power and high-speed engine of the ship is becoming as a major contributor causing excessive noise and vibration. Other fittings as well as equipment installed on board, it makes equipment failure or other defect by resonance. This causes a lot of M/H(Man Hour) for repairs and the reliability of the company is invading even be negative because the clients give much comment. Thus, it's being studied for any fittings installed on board to maintain the safe operation and to prevent any problem during the performance in any operating conditions. In this study, it was investigated to solve these problems for the supports of the various fittings for easy installation-related support that each type of intensity and shape and manufacturing method using structural analysis program(DNV Nauticus Hull 3D Beam). Namely, it would be applied to the very large crude carriers in consideration of mechanics of materials of the support equipment by providing the fact that dynamics analysis of the structural characteristics of the equipment and the support of the production installation is easy and productivity can be high standards for geometry and thereby to simplify the analysis task to design changes at the same time and to minimize the reinforcement for the supports.