• Journal of Advanced Marine Engineering and Technology
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• v.36 no.8
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• pp.1010-1015
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• 2012

DME(Dimethyl ether) is the one of the massive energy sources synthesized from natural gas. KOGAS has already developed the commercial-scale production plant of DME and has been doing to obtain overseas resources to meet the domestic needs. This paper presents the DME storage tank design criteria by stress and strain analysis, and the experimental study on the evaporation phenomena of DME by thermal intake and physical rolling movement of DME FPSO or cargo vessel, because the various moving motions along with heat intake cause the evaporation of low temperature liquid. The experimental result shows that the evaporation rate was increased with larger rolling degree and higher liquid level. The rolling motion leads to evaporate about 20% increase with 15 degree rolling based on the evaporation quantity without rolling.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.1
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• pp.125-134
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• 2003

The present paper is concerned to the thermal analysis during the cool-down period of 138,000 m$^3$class GTT MARK-III membrane type LNG carrier servicing with LNG from the Middle East to Korea. It is the cool-down period that cools the insulation wall and the gas in LNG tank to avoid the thermal shock as the start of loading of -162$^{\circ}C$ LNG. For six hours of the standard cool-down period, the temperature of NG falls down from -4$0^{\circ}C$ to -13$0^{\circ}C$ and especially the mean temperature of the 1st barrier in the top side insulation wall falls down from -38.38$^{\circ}C$ to -122.42$^{\circ}C$ in case of IMO design condition. By the 3-D numerical calculation about the cargo tank and the cofferdam, the temperature variation in hulls and insulations is precisely predicted in this paper. And the mean temperature variation of gas is calculated as the function of the spraying rate by the heat balance model during the cool-down period.

• Journal of Sensor Science and Technology
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• v.21 no.4
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• pp.276-282
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• 2012

Vessels receive stress during their navigations as well as during their cargo operations. This stress may cause damages to the hull and may result in accidents. So the hull stress monitoring system(HSMS) is recommended in order to prevent these accidents. In this paper, we manufactured fiber Bragg grating(FBG) sensor and the model ship for towing tank experiments. The strain characteristics of the model ship on the water wave were measured through the towing tank experiment. The FBG sensors and electric strain gauges were attached on the connection jig, and then the characteristics of the FBG sensor were compared with those of the electric strain gauge. The strain of model ship was increased according to the increment of the amplitude of water wave. In particular, the largest strain was measured in the center of the model ship. As the wave period increased, the strain of model ship was decreased.

• Journal of Ocean Engineering and Technology
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• v.24 no.5
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• pp.31-38
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• 2010

The Floating storage and re-gasification unit (FSRU), which has large cargo storage tanks, is a floating liquefied natural gas (LNG) import terminal. The sloshing motion in tanks that are partially filled with LNG can cause impact pressure on the containment system and affect the global motion of the FSRU. Therefore, the accurate prediction of sloshing motion has been a significant issue in the offshore gas production industry. In this paper, a particle method based on the moving particle semi-implicit (MPS) method proposed by Koshizuka and Oka (1996) has been modified to predict sloshing motion accurately in a rectangular tank with the filling ratio of water. The simulation results, including the violent sloshing of the fluid, were validated by comparison with the original MPS method.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.3
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• pp.446-450
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• 2012

I.G.G is abbreviation for inert gas generator high temperature in cargo tank it desulfurize, exhaust and froze the gas that combined brimstone element and soot, then supply inert gas by blower and mack tank inside incombustible range this is equipment that nip in the bud the explosion. The blower for suppling inactivated gas has big impeller with heavy weight to achieve the high pressure, it causes a delay for first operation time and too much load is delivered to motor, total destruction by fire of motor is happen frequently. On this research, we will reduce the size and weight of impeller and install it with several stage, it makes an effect for reducing the first operation time. We also intend to contribute to efficient I.G.G. blower design by research a flow rate and pressure specialty from the diameter of impeller number of blades and size of casing.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.1309-1314
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• 2008

I.G.G is abbreviation for Inert Gas Generator, High temperature in Cargo Tank it desulfurize, exhausted and froze the gas that combined brimstone element and soot, then supply Inert gas by blower, and mack tank inside incombustible range this is equipment that nip in the bud the explosion. The blower for suppling inactivated gas has big impeller with heavy weight to achieve the high pressure, it causes a delay for first operation time and too much load is delivered to motor, total destruction by fire of motor is happening frequently. On this research, we will reduce the size & weight of impeller and install it with several stage, it makes an effect for reducing the first operation time. We also intend to contribute to efficient IGG blower design by research a flowing & pressure specialty from the diameter of impeller, number of blade, and size of casing.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.10a
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• pp.33-34
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• 2015

The voyage and cargo volume passing through the Arctic route (NSR) have been gradually increased. The ship-ice collision is one of the most biggest factors threatening the safety navigation of ice-going ships. A lot of researchers are trying to reveal the ship-ice collision mechanism. In this study, some tests that a model ship is forced to collide with disk-shaped synthetic ice are carried out in a towing tank. Then, ice floe's motion (velocity and trajectory) is measured by machine vision inspection.

• Journal of Ocean Engineering and Technology
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• v.23 no.4
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• pp.12-18
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• 2009

The present study focused on the compressibility of partially filled fluids in a sloshing tank. Filling ratios ranging from 18% to 26% were used to find compressible impact on a vertical wall. The model test was for 1/25 scale of a 138 K LNGC cargo tank. To investigate the two dimensional phenomenon of sloshing, a longitudinal slice model was tested. A high speed camera was used to capture the flow field, as well as the air pocket deformation. The pressure time history synchronized with the video images revealed the entire compressible process. Three typical impact phenomena were observed: hydraulic jump, flip through, and plunging breaker. In particular, the pressure time history and flow pattern details for flip through and plunging breaker are presented.

• Journal of Advanced Research in Ocean Engineering
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• v.4 no.4
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• pp.185-194
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• 2018

In this study, the extreme sloshing pressure was predicted using various statistical models: three-parameter Weibull distribution, generalized Pareto distribution, generalized extreme value distribution, and three-parameter log-logistic distribution. The estimation of sloshing impact pressure is important in design of liquid cargo tank in severe sea state. In order to get the extreme values of local impact pressures, a lot of model tests have been carried out and statistical analysis has been performed. Three-parameter Weibull distribution and generalized Pareto distribution are widely used as the statistical analysis method in sloshing phenomenon, but generalized extreme value distribution and three-parameter log-logistic distribution are added in this study. Additionally, statistical distributions are fitted to peak pressure data using three different parameter estimation methods. The data were obtained from a three-dimensional sloshing model text conducted at Seoul National University. The loading conditions were 20%, 50%, and 95% of tank height, and the analysis was performed based on the measured impact pressure on four significant panels with large sloshing impacts. These fittings were compared by observing probability of exceedance diagrams and probability plot correlation coefficient test for goodness-of-fit.

• Journal of Ocean Engineering and Technology
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• v.26 no.4
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• pp.50-56
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• 2012

When a liquid cargo tank is partially filled with fluid, internal impact loads can be occurred from the vessel's motions. In this study, liquid sloshing problems with a thin top layer of particles with a lighter density than water and the coupling effects of the liquid-sloshing/vessel-motion were investigated in order to reduce the sloshing-induced impact loads. The PNU-MPS (Pusan-National-University-modified Moving Particle Simulation) method for solving the liquid motion inside a tank and the CHARM3D BEM (Boundary Element Method) based time-domain ship motion analysis program for vessel-motion simulation were coupled. From the simulation results, we could see that the floaters seemed to be quite effective at reducing the sloshing impact loads in the case of tank-only sloshing problems, but not as much for the coupling problem with vessel motion.