• 한국유체기계학회 논문집
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• 제18권3호
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• pp.20-25
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• 2015

In this study, there are 6 mixers that are installed in a 600,000 barrel tank. We identified internal flow characteristics of floating roof tank with varying the number of operation from 4 to 6 because mixer is a variable that influence flow characteristics of the tank. And while varying an angle from Right $60^{\circ}$, Right $30^{\circ}$, Left $30^{\circ}$ to Left $60^{\circ}$, we identified internal flow characteristics of the tank. As a result, maximum velocity of flow was 0.02m/s stationarily when we changed the number of operation from 4 to 6. Maximum velocity of flow by change of an angle was from 0.42m/s to 0.47m/s. Therefore, we identified that these factors don't have a great influence on internal flow characteristics of a tank by investigating results with varying the number of operation and an angle.

• 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.

• 한국안전학회지
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• 제34권4호
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• pp.41-48
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• 2019

In October 2018, a large fire occurred after an explosion in an internal floating roof tank (IFRT) that stores gasoline by wind lantern in Goyang city, Gyeonggi-do. Although there was no casualty damage, the fire inside the tank lasted for 17 hours, and caused a great wave socially, and it was a chance to review the safety of the atmospheric storage tank. In this study, the necessity of installing a flame arrester at peripheral vents was examined through the calculation of the size of ventilation pipe and ventilation rate of internal floating roof tanks in terms of the function of the peripheral vent. Next, the necessity of the emergency shut-off valve linked with the high-level alarm to prevent the overflow of the atmospheric storage tank was confirmed by LOPA. Finally, safety measures to prevent overpressure, flame propagation and overflow which cause major accidents in atmospheric storage tank are suggested.

• Earthquakes and Structures
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• 제15권4호
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• pp.411-417
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• 2018

To solve the seismic response problem of a vertical floating roof tank with base isolation, the floating roof is assumed to experience homogeneous rigid circular plate vibration, where the wave height of the vibration is linearly distributed along the radius, starting from the theory of fluid velocity potential; the potential function of the liquid movement and the corresponding theoretical expression of the base shear, overturning the moment, are then established. According to the equivalent principle of the shear and moment, a simplified mechanical model of a base isolation tank with a swinging effect is established, along with a motion equation of a vertical storage tank isolation system that considers the swinging effect based on the energy principle. At the same time, taking a 150,000 m 3 large-scale storage tank as an example, a numerical analysis of the dampening effect was conducted using a vibration mode decomposition response spectrum method, and a comparative analysis with a simplified mechanical model with no swinging effect was applied.

• 한국화재소방학회논문지
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• 제33권1호
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• pp.45-49
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• 2019

본 연구는 옥외저장탱크에서 발생한 화재의 근본적인 원인분석을 통해 저장탱크의 안전을 유지할 목적으로 수행되었다. 옥외저장탱크는 위험물을 장기간 저장하기 위한 고정장치로 탱크본체 및 부속장치로 구성되며, 부속장치는 벤트 시스템, 브레더 밸브, 화염방지기 등으로 구성된다. 화염방지기는 옥외저장탱크의 화재 폭발을 방지하기 위해 필요한 안전장치이다. 하지만 최근 발생한 옥외저장탱크 화재를 계기로 기존에 설치되어 운용중인 옥외저장탱크에 안전성 확보 차원에서 화염방지기를 의무적으로 설치해야 하는지 국내 외 기준을 비교 분석하여 화염방지기 설치가 필요함을 제시하였고, 화염방지기의 성능을 검증할 수 있는 국내기준이 부족하므로 외국 기준을 참고하여 보완할 필요성이 있다.

• 방재기술
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• 통권2호
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• pp.71-73
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• 1988

• Wind and Structures
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• 제31권6호
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• pp.483-493
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• 2020

Large cylindrical floating-roof tanks, constructed as oil containers, are usually distributed regularly in open area and easily exposed to severe wind loads. However, wind pressures around these grouped squat tanks appear to have not been clearly given in design codes or thoroughly studied in existing researches. This paper conducts a detailed investigation on wind loads on the external wall of a four-tank group in square arrangement. To achieve that, wind tunnel tests are carried out on both empty and full tank groups, considering various wind angles and spacing. Results show that 3 regions in elevation can be identified on the tank shell according to the circumferential wind pressure distribution. The upper 2 regions cover a relatively small portion of the shell where excessive negative pressures are spotted, setting an alarm to the design of the top angle and stiffening rings. By comparing results on grouped tanks to those on an isolated tank, grouping effects concerning wind angle, tank position in group and spacing are discussed. Deviations on pressure distributions that will compromise structural safety are outlined, including the increase of negative pressures, the shift of maximum pressure locations as well as the change of positive pressure range. And, several potentially unfavourable wind pressure distributions are selected for further analyses.

• Coupled systems mechanics
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• 제2권4호
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• pp.389-410
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• 2013

Three-dimensional Lagrangian fluid finite element is applied to seismic response analysis of an oil storage tank with a floating roof. The fluid element utilized in the present analysis is formulated based on the displacement finite element method considering only volumetric elasticity and its element stiffness matrix is derived by using one-point integration method in order to avoid volumetric locking. The method usually adds a rotational penalty stiffness to satisfy the irrotational condition for fluid motion and modifies element mass matrices through the projected mass method to suppress spurious hourglass-mode appeared in compensation for one-point integration. In the fluid element utilized in the present paper, a small hourglass stiffness is employed. The fluid and structure domains for the objective oil storage tank are modeled by eight-node solid elements and four-node shell elements, respectively, and the transient response of the floating roof structure or the free surface are evaluated by implicit direct time integration method. The results of seismic response analyses are compared with those by other method and the validation of the present analysis using three-dimensional Lagrangian fluid finite elements is shown.

• Wind and Structures
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• 제31권6호
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• pp.495-508
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• 2020

To investigate the structural behaviour of grouped tanks under wind loads, 2 problems need to be figured out, wind pressures on tank shells and critical loads of the shell under these pressure distribution patterns. Following the wind tunnel tests described in the companion paper, this paper firstly seeks to obtain wind loads on the external wall in a squarely-arranged cylindrical tank group by numerical simulation, considering various layouts. The outcomes demonstrate that the numerical method can provide similar results on wind pressures and better insights on grouping effects through extracted streamlines. Then, geometrically nonlinear analyses are performed using several selected potentially unfavourable wind pressure distributions. It is found that the critical load is controlled by limit point buckling when the tank is empty while excessive deformations when the tank is full. In particular, significant reductions of wind resistance are found on grouped full tanks compared to the isolated tank, considering both serviceability and ultimate limit state, which should receive special attention if the tank is expected to resist severe wind loads with the increase of liquid level.