• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 봄 학술발표회논문집
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• pp.111-118
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• 2000

Concrete cracking due to the temperature gradient across the wall, caused by the difference in temperature between cryogenic liquid natural gas stored and surrounding environment of in-ground LNG storage tank, is investigated in this study. Crack propagation of concrete LNG tank is effectively simulated by using a layered degenerated shell element. In addition, material nonlinearity is taken into consideration on the basis of the nonlinear elastic-orthotropic model. Finally, numerical analysis for a real LNG storage tank is conducted with the objective to verify the efficiency of the introduced model.

• 한국초전도ㆍ저온공학회논문지
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• 제22권3호
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• pp.25-30
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• 2020

The diminishing of heat leak into cryogenic vessels can prolong the storage time of cryogenic liquid. With the storage of cryogenic liquid reducing, the heat leak decreases, while the actual storage time increases. Regarding to the theoretical analysis, the obtained results seems to be constructive for the cryogenic insulation system applications. This study presents a predictive assessment of heat leak occurring in non-vacuum tanks with a single layer of insulation. A Radial steady-state heat transfer, based on heat conduction equation, is taken into consideration. Graphical results show the thermal performance of the insulation used, they also allow us to choose the appropriate insulation thickness according to the shape and diameter of the storage tank.

• 대한설비공학회지:설비저널
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• 제14권2호
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• pp.98-107
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• 1985

In this thesis, the Sol-Air temperature distribution for the side-wall of a cylindrical cryogenic storage tank made of nonhomogenious composite layer was studied, in order to calculate the thermal load by Newton's cooling law, when the solar radiation was applied upon the side wall. In the analysis, the atmospheric slab was assumed to be horizontal and infinitely large, and the Sol -Air temperature, which was found by the Net- Radiation method considering the longwave radiation wi th surroundings, was used for boundary condition. Energy equation and boundary conditions were normalized by the defined reference- temperature, and solved. The solutions were developed by the Fourier cosine series. Then, the Sol-Air temperature distribution for the side-wall of LNG storage tank was calculated.

• Journal of Advanced Marine Engineering and Technology
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• 제35권4호
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• pp.451-459
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• 2011

초저온 구조 재료로 극저온에서 기계적 특성이 우수한 300계열의 오스테나이트계 스테인리스강이 널리 사용되어진다. 이 중에서도 오스테나이트의 안전성 향상을 위해 몰리브덴을 첨가한 316강이나 용접 중에 입계 석출을 줄이기 위해 탄소의 함유율을 감소시킨 316L강, 그리고 질소를 첨가시켜 강도와 오스테나이트를 동시에 향상시킨 316LN강이 대표적으로 많이 사용된다. 하지만 초저온 재료들의 용접조건 및 온도변화에 대한 기계적 특성 연구가 미진한 상태이다. 본 논문에서는 초저온 구조물에서 많이 사용되어지는 304강의 용접조건 및 온도변화에 대한 기계적 특성을 연구하였다.

• 한국가스학회지
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• 제5권4호
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• pp.49-55
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• 2001

본 연구에서는 $9\%$ 니켈강재로 제작된 완전 방호식 내부탱크 구조물의 설계 안전성 문제를 유한요소법으로 해석하고자 한다. 내부탱크 구조물에 대한 수치적 해석결과에 의하면 내부탱크에 부착된 톱가더와 스티프너는 내부탱크의 변형율과 응력을 제어하는 중요한 역할을 하고 있다. 내부탱크에 작용하는 여러 하중에서 초저온 액체에 의한 유체정압은 $-162^{\circ}C$의 초저온 온도하중보다 더 큰 영향을 미치고 있음을 알 수 있다. 그러나, 내부탱크에 작용하는 자중량 좌굴하중에 의한 영향은 내부탱크 구조물이 충분한 강도로 이미 설계되어 있으므로 대단히 자게 나타났지만, 특히 톱가더나 스티프너의 역할은 미미한 것으로 나타났다.

• 한국항공우주학회지
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• 제35권7호
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• pp.592-600
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• 2007

최근에 발사체의 경량화를 위해 추진제 탱크의 재료를 복합재료로 대체하기 위한 연구가 많이 진행되고 있다. 본 연구에서는 극저온용으로 개발된 복합재와 알루미늄 라이너로 구성된 타입 3 추진제 탱크를 제작하고 실제 극저온 상태의 운용환경을 고려한 실험을 수행하였다. 이를 위해 액체 질소를 제작된 타입 3 탱크에 주입하고 기체 질소를 이용하여 가압하였다. 실험수행과정에서 헬리컬 층과 후프 층 사이에서 층간 분리 현상이 관찰되었으며, 이에 대한 원인을 분석하기 위해 해석적 방법과 실험적 방법이 사용되었다. 해석적 방법에서는 점진적 파손 해석을 고려한 열탄성 해석으로부터 파손 지수를 평가하였으며 실험적 방법에서는 타입 3 탱크를 쉽게 모사할 수 있는 복합재/알루미늄 링 시편의 액체질소 담금 시험을 통해 헬리컬 층과 후프 층 사이의 계면을 관찰하였다.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2001년도 학술대회 논문집
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• pp.48-49
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• 2001

Cryogenic technology is one of the key technologies for fusion reactor equipped with superconducting coil for plasma confinement. The KSTAR(Korea Superconducting Tokamak Advanced Research)Project is in progress since 1996. Major parameters of the KSTAR tokamak are : major radius 1.8m, minor radius 0.5m, toroidal field 3.5 Tesla and plasma current 2MA with a strongly shaped plasma cross-section and double -null diverter. Considering practical engineering constraints, the KSTAR device is designed for a pulse length of 300 sec in up-graded operation mode but in the initial configuration would provide a pulse length of 20 sec provided by the poloidal coil system in base-line operation mode. The cryogenic system is composed as follows : cold box, helium compressor system, distribution box, helium gas buffer tank, helium gas purifying system, gas recovery system, liquid helium storage dewar, current lead box, current bus line and liquid nitrogen storage tank.

• 한국가스학회:학술대회논문집
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• 한국가스학회 1998년도 추계학술발표회 논문집
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• pp.115-119
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• 1998

• 한국수소및신에너지학회논문집
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• 제27권6호
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• pp.642-650
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• 2016

One of the most feasible solution for reducing the excessive energy consumption and carbon dioxide emission is usage of more efficient fuel such as hydrogen. As is well known, there are three viable technologies for storing hydrogen fuel: compressed gas, metal hydride absorption, and cryogenic liquid. In these technologies, the storage for liquid hydrogen has better energy density by weight than other storage methods. However, the cryogenic liquid storage has a significant disadvantage of boiling losses. That is, high performance of thermal insulation systems must be studied for reducing the boiling losses. This paper presents an experimental study on the effective thermal conductivities of the composite layered insulation with aerogel blankets($Cryogel^{(R)}$ Z and $Pyrogel^{(R)}$ XT-E) and Multi-layer insulation(MLI). The aerogel blankets are known as high porous materials and the good insulators within a soft vacuum range($10^{-3}{\sim}1$ Torr). Also, MLI is known as the best insulator within a high vacuum range(<$10^{-6}{\sim}10^{-3}$ Torr). A vertical axial cryogenic experimental apparatus was designed to investigate the thermal performance of the composite layered insulators under cryogenic conditions as well as consist of a cold mass tank, a heat absorber, annular vacuum space, and an insulators space. The composite insulators were laminated in the insulator space that height was 50 mm. In this study, the effective thermal conductivities of the materials were evaluated by measuring boil-off rate of liquid nitrogen and liquid argon in the cold mass tank.

• 한국산업융합학회 논문집
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• 제24권6_2호
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• pp.787-793
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• 2021

The global demand for Liquefied Natural Gas(LNG) continues to increase and is facing a big cycle. To keep pace with the increase in international demand for LNG, the demand for LNG fueled ships is also increasing. Since LNG fuel tanks are operated in a cryogenic environment, insulation technology is very important, and although there are various types of insulation applied to Type C tanks, multi-layer insulation and vacuum insulation are typically applied. Powder insulation materials are widely used for storage and transportation of cryogenic liquids in tanks with such a complex insulation structure. In this study, compression tests at room and cryogenic temperature were performed on closed perlite, glass bubble, and fumed silica, which are representative powder insulation material candidates. Finally, the applicability to the Type C fuel tank was reviewed by analyzing the experimental results of this study.