• 한국기계가공학회지
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• 제17권1호
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• pp.153-160
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• 2018

A pressure vessel consists of an inner tank and the outer tank; the material of the inner tank is austenite stainless steel, and the outer tank is general carbon steel. As the storage amount increase, the size of the inner tank for LNG also increases, which eventually increases the weight of the LNG storage tank. The Cold Stretch method can transport and store the LNG in a larger amount than the conventional pressure container, and the weight of the pressure vessel can also be reduced at 50 70% due to the reduction of the thickness, which is excellent from an economic and energy consumption perspective. Although the Cold Stretch method has these advantages, the domestic situation has not developed any related legislation. In this study, the actual production of pressure vessels using the Cold Stretch method will be processed and the volume expansion after the Cold Stretch will be checked and compared with the mechanical properties.

• Ocean Systems Engineering
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• 제8권1호
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• pp.57-77
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• 2018

The present paper deals with the finite element analysis of water tanks with rigid baffle. Fluid is discretized by two dimensional eight-node isoparametric elements and the governing equation is simulated by pressure based formulation to reduce the degrees of freedom in the domain. Both free vibration and force vibration analysis are carried out for different sizes and positions of block at tank bottom. The fundamental frequency depends on block height and it reduces with the increase of block height. The variation of hydrodynamic pressure on tank walls not only depends of the exciting frequency but also on the size and position of rigid block at tank bottom. The hydrodynamic pressure has higher value when the exciting frequency is equal and lower than the fundamental frequency of the water in the tank. Similarly, the hydrodynamic pressure increases with the increase of width of the block for all exciting frequencies when the block is at the centre of tank. The left and right walls of tank have experienced different hydrodynamic pressure when the block is placed at off-centre. However, the increase in hydrodynamic pressure on nearest tank wall becomes insignificant after a certain value of the distance between the wall and the rigid block.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1218-1231
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• 2008

Recently the energy dependence of LNG resource is being increased. So the enlargement of LNG storage is constructed in the coastal area. Most of LNG tanks are constructed below the ground level, and thus the hydraulic uplift pressure could be a problem against the weight of tank structure. Specifically, the settlement of foundation soil in the LNG tank is also important in the aspect of safety. The low temperature around LNG tank is induced the ground freezing and hence increasing the soil volume and earth pressure. The additional lateral earth pressure due to ground freezing could be applied to the LNG tank. In this study, the stability of LNG storage tank was evaluated with consideration of freezing earth pressure by using computer program TEMP-W.

• 한국항해항만학회지
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• 제27권5호
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• pp.459-464
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• 2003

강제 횡동요 실험을 통하여 동요하는 탱크의 내부압력을 폭정하고, 탱크의 내부압력을 추정하는 간단한 이론식을 제시하였다. 청수로 채워진 사각 탱크를 동요실험에 사용하였으며, 탱크의 안쪽 벽과 바닥에 압력게이지를 설치하여 내부압력의 시간변화량을 측정하였다. 측정된 탱크의 내부압력의 실험값과 이론식을 이용한 계산값을 비교하였다. 횡동요 하는 탱크내부의 압력을 구하기 위해 압력중심을 고려하여 추정하는 방법을 연구하였다.

• 한국전산구조공학회논문집
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• 제26권5호
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• pp.327-333
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• 2013

이 연구의 목적은 축소된 탱크 모델에서 측정되어진 슬로싱 압력을 이용하여 실제 크기의 탱크 모델에서의 압력을 예측하는 것이며, 또한 예측된 압력으로 LNG 코너 블럭의 슬로싱 하중에 의한 구조 강도를 평가하는 것이다. 이 목적을 위하여, Ansys CFX 프로그램을 이용하여 138K급 LNG 화물창 시스템의 크기 비율에 따른 슬로싱 해석을 수행 하였으며, 크기 비율에 따른 슬로싱 평균 압력 및 최대 피크 압력을 측정하였다. 또한, 측정된 압력은 프루드 법칙에 의해 실제 138K 크기의 압력으로 변환하여 실선 크기의 KC-1 코너블럭에 대한 구조강도 평가를 수행하였다.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2000년도 KIASC Conference 2000 / 2000년도 학술대회 논문집
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• pp.48-51
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• 2000

The behavior of cryogenic liquid stored in a closed cryogenic tank has been studied at various liquid levels, as a function of pressure and temperature on time, assuming heat leak(NER) is 0.7%/day. The pressure depends, as expected, on the liquid-vapor ratio in a tank. The calculation shows that if liquid level is as high as 90%,much higher than the critical volume ration, in a closed tank of designed pressure 11 bar, it takes 5.4 to 15days for the entire volume of the tank to be filled with liquid and 11 to 22 days for the tank to be exploded. If a closed tank is full of liquid, it is extremely dangerous because of abrupt pressure increase so that the safety devices are necessary to vent out pressurized gas. These phenomena can be explained with the liquid heat capacity, latent heat and compressibility.

• 한국가시화정보학회지
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• 제21권1호
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• pp.31-39
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• 2023

Sloshing of the fluid having a free surface produces an impact force on a tank wall subjected to external excitation. This paper investigates the effect of cylindrical structures in a rectangular sloshing tank under translational harmonic excitations. By varying the number of installed cylinders in the tank, the characteristics of the free-surface deformation is experimentally observed, and the peak pressure on the tank wall is extracted by threshold values. To predict the peak pressure, the numerical simulation is also conducted using smoothed particle hydrodynamics (SPH), and the peak values are compared with the experimental results. Furthermore, pressure and velocity fields in the tank and free-surface shape are analyzed at the moment of impact.

• International Journal of Aeronautical and Space Sciences
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• 제18권4호
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• pp.807-815
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• 2017

For liquid rocket engine(LRE)-based space launch vehicles, longitudinal instability, often referred to as the pogo phenomenon in the literature is predicted. In the building block of system-level task, accurate dynamic modeling of a fluid-filled tank is an essential. This paper attempts to apply the virtual mass method that accounts for the interaction of the vehicle structure and the enclosed liquid oxygen to LOX-filled tanks. The virtual mass method is applied in a modal analysis considering the hydroelastic effect of the launch vehicle tank. This method involves an analysis of the fluid in the tank in the form of mass matrix. To verify the accuracy of this method, the experimental modal data of a small hemispherical tank is used. Finally, the virtual mass method is applied to a 1/8-scale space shuttle external tank. In addition, the LOX tank bottom pressure in the external tank model is estimated. The LOX tank bottom pressure is the factor required for the coupling of the LOX tank with the propulsion system. The small hemispherical tank analysis provides relatively accurate results, and the 1/8-scale space shuttle external tank provides reasonable results. The LOX tank bottom pressure is also similar to that in the numerical results of a previous analysis.

• 한국가스학회지
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• 제17권6호
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• pp.1-7
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• 2013

이 논문에서는 특례기준에 따라 국내에서 최초로 제작하고 검사한 LNG 탱크 컨테이너를 이용하여 육상 및 해상 운송 시연사업을 하고, 탱크 컨테이너를 운송할 때 탱크 컨테이너 내부에 충전된 LNG의 압력변화와 탱크 컨테이너의 실제 압력유지기간을 측정하였다. 탱크 컨테이너 내부의 압력은 충전 직후에는 급속하게 상승하고, 탱크 컨테이너를 이동할 때 급속히 하강하나, 일정시간이 경과한 후에는 기액평형상태 그래프의 온도-압력 변화와 일치함을 확인하였다. 또한, 탱크 컨테이너의 실제 압력유지기간은 특례기준에서 규정한 20일 이상을 만족함을 확인하였다.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2005년도 연구개발 발표회 논문집
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• pp.566-572
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• 2005

The most crucial factor in membrane LNG ships to ensure sage operations, is how to effectively control tank pressure at the time of excessive generation of boil off gas (BOG). When the ships carry out tank cool down with her retaining heel prior to arrival at loading port, the vessel encounters the critical situation of excessive BOG and high tank pressure that can lead to high degree of risk. This is to provide one of the best ways to secure safe and effective LNG ship operations focusing on the detailed methods of tank cool down to achieve ATR(Arrival Temperature requirement) without building up high tank pressure and excessive BOG and calculating the appropriate heel quantity to be unutilized for tank cool down and fuel during ballast voyage.