• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제29회 추계학술대회논문집
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• pp.389-392
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• 2007

별도의 가압장치가 없이 산화제탱크 내에 저장된 $N_2O$액체산화제가 공급될 때 액체에서 기체로의 상변화를 고려하여 $N_2O$액체 산화제의 유량공급특성을 예측하였다. 보다 정확한 산화제 공급특성을 계산하기 위해 산화제의 압력과 온도에 따른 $N_2O$의 물성치 변화를 고려하였으며 오리피스 형상과 토출계수 관계식을 이용하여 산화제 유량을 계산하였다. 그리고 산화제 공급에 따른 산화제탱크 내의 압력변화를 측정하고 해석결과와 비교하였다.

• Earthquakes and Structures
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• 제26권5호
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• pp.337-348
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• 2024

This paper presents a new seismic isolation design for liquid storage tank (LST). The seismic isolation system includes: LST, flexible membrane, sand mat and rolling seismic isolation devices. Based on the mechanical equilibrium theory, the symmetric concave rolling restoring force model of the isolation device is derived. Based on the elasticity theory and restoring force model of the seismic isolation, a simplified mechanical model of LST with the new seismic isolation is established. The rationality of the seismic isolation design of LST is explored. Meanwhile, the seismic response of the new seismic isolation LST is investigated by numerical simulation. The results show that the new seismic isolation tank can effectively reduce the seismic response, especially the control of base shear and overturning moment, which greatly reduces the risk of seismic damage. The seismic reduction rate of the new seismic isolation storage tanks in Class I, II, and III sites is better than that in Class IV sites. Moreover, the seismic isolation device can effectively control the ground vibration response of storage tanks with different liquid heights. The new seismic isolation LST design provides better isolation for slender LSTs than for broad LSTs.

• International Journal of Naval Architecture and Ocean Engineering
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• 제9권1호
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• pp.114-125
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• 2017

This paper addresses a study of inner-tank sloshing effect on motion responses of a Floating Liquefied Natural Gas (FLNG) system, through experimental analysis and numerical modeling. To investigate hydrodynamic characteristics of FLNG under the conditions of with and without LNG-tank sloshing, a series of numerical simulations were carried out using potential flow solver SESAM. To validate the numerical simulations, model tests on the FLNG system was conducted in both liquid and solid ballast conditions with 75% tank filling level in height. Good correlations were observed between the measured and predicted results, proving the feasibility of the numerical modeling technique. On the verified numerical model, Response Amplitude Operators (RAOs) of the FLNG with 25% and 50% tank filling levels were calculated in six degrees of freedom. The influence of tank sloshing with varying tank filling levels on the RAOs has been presented and analyzed. The results showed that LNG-tank sloshing has a noticeable impact on the roll motion response of the FLNG and a moderate tank filling level is less helpful in reducing the roll motion response.

• 한국해양공학회지
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• 제26권4호
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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.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.597-602
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• 2006

Many researches have been studied several vibration control device such as TMD and TLD to reduce the influence of wind or seismic waves for high-rise buildings. TLD provides some advantages such as easy installation and low maintenance cost. However, because of the difficulties in evaluating the characteristics of TLD, the dynamic characteristics of TLD must be investigated by experiment or analysis. In this study, the dynamic response analysis of structure with TLD was carried out to verify the vibration control ability of the proposed TLD for high-rise building with about 60 stories. A real seismic wave was used, and the parameter of interest was chosen by the height of water level in the same shape of water tank. From the numerical results, the responses of structure with water tank were confirmed to be safer than those of structure without water tank.

• International Journal of Naval Architecture and Ocean Engineering
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• 제7권4호
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• pp.670-690
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• 2015

In this paper, numerical investigations for tank sloshing, based on commercial CFD package FLUENT, are performed to study effects of boundary layer grid, liquid viscosity and compressible air on sloshing pressure, wave height and rising time of impact pressure. Also, sloshing experiments for liquids of different viscosity are carried out to validate the numerical results. Through comparison of numerical and experimental results, a computational model including boundary layer grid can predict the sloshing pressure more accurately. Energy dissipation due to viscous friction leads to reduction of sloshing pressure and wave elevation. Sloshing pressure is also reduced because of cushion effect of compressible air. Due to high viscosity damping effect and compressible air effect, the rising time of impact pressure becomes longer. It is also found that liquid viscosity and compressible air influence distribution of dynamic pressure along the vertical tank wall.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2009년 춘계학술대회논문집
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• pp.215-222
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• 2009

In the present study, a numerical analysis on the sloshing in a tank with the harmonic motion was investigated. A VOF method was used for two-phase flows inside the sloshing tank and a source term of the momentum equation was applied for the harmonic motion. This numerical method was verified by comparing its results with the available experimental data. The sloshing in a tank causes the instability of the fluid flows and the fluctuation of the impact pressure on the tank. By these phenomena of the tank sloshing, the sloshing problems such as the failure and the noise of system can be generated. For the reduction of these sloshing problems, the various baffles such as the horizontal/vertical plate baffles and the porous baffles inside the tank are installed. With the installations of these baffles, the characteristics of the liquid behavior in the sloshing tank, the impact pressure on the wall, the amplitude of the free surface near the wall and the sloshing noise were numerically analyzed.

• Journal of Mechanical Science and Technology
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• 제18권5호
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• pp.820-829
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• 2004

The In-Containment Refueling Water Storage Tank (IRWST), one of the design improvements applied to the APR -1400, has a function to condense the high enthalpy fluid discharged from the Reactor Coolant System (RCS). The condensation of discharged fluid by the tank water drives the tank temperature high and causes oscillatory condensation. Also if the tank cooling water temperature approaches the saturated state, the steam bubble may escape from the water uncondensed. These oscillatory condensation and bubble escape would burden the undue load to the tank structure, pressurize the tank, and degrade its intended function. For these reasons simple analytical modeling and experimental works were performed in order to predict exact tank temperature distribution and to find the effective cooling method to keep the tank temperature below the bubble escape limit (93.3$^{\circ}C$), which was experimentally proven by other researchers. Both the analytical model and experimental results show that the temperature distributions are horizontally stratified. Particularly, the hot liquid produced by the condensation around the sparger holes goes up straight like a thermal plume. Also, the momentum of the discharged fluid is not so strong to interrupt this horizontal thermal stratification significantly. Therefore the layout and shape of sparger is not so important as long as the location of the sparger hole is sufficiently close to the bottom of the tank. Finally, for the effective tank cooling it is recommended that the locations of the discharge and intake lines of the cooling system be cautiously selected considering the temperature distribution, the water level change, and the cooling effectiveness.

• 한국화재소방학회논문지
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• 제34권2호
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• pp.86-93
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• 2020

본 연구는 옥외저장탱크에서 발생한 화재·폭발사고의 근본적인 사례분석을 통해 저장탱크의 안전을 유지할 목적으로 수행되었다. 이 사고는 저장탱크 야드에 사업장 외에서 날아온 풍등이 저장탱크 주변 잔디에 떨어지며 발생한 잔재 화재가 서서히 확산되어 탱크 내부의 유증기와 만나 폭발·화재로 이어진 사고였다. 사고의 원인을 밝혀내기 위하여 CCTV영상분석을 통한 대기확산 조건 도출, 전산유체역학을 이용한 풍향 분석, 플러팅 루프가 최저 위치일 때의 탱크 내부 유증기 발생량, 최고 위치일 때의 탱크 내부 유증기 거동을 통하여 저장탱크의 폭발이 일어난 원인을 밝혀내어 저장탱크의 레벨을 내부부상형 지붕 이하로 유지했을 경우 위험물이 충전되면서 그 공간에 있던 유증기가 내부 부상지붕위에 정체될 가능성이 있으므로 저장탱크의 Low liquid level이 폰튠 서포트 밑에 위치하지 않도록 운전절차를 개선하고, 오픈 벤트에는 화염방지기를 설치하여 화염이 저장탱크로 유입하지 못하도록 하는 대책을 제시하고자 한다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제28회 춘계학술대회논문집
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• pp.34-37
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• 2007

액체산소를 작동유체로 하여 추진제 공급배관에 대한 충진 및 대기 시험을 수행하였다. 추진제 공급 시스템은 추진제 탱크의 출구에 필터가 장착된 형상이다. 추진제의 충진이 완료된 후 대기 과정동안 액체산소의 증발과 이것이 시스템의 재순환 성능에 미치는 영향을 살펴보았다. 추진제의 충진 속도와 탱크 얼리지의 압력이 배관 내 액체산소의 상태에 영향을 미치는 것을 확인하였다. 필터의 장착 위치로 인해 대기 과정동안 배관 내부에서 geysering 현상은 발생하지 않았다.