• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2003.05a
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• pp.185-190
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• 2003

산업체 등에서 사용되고 있는 가스들중에서 일반적인 가스들과는 달리 위험한 가스(heavy gas)들은 누출사고시에 이들 고유한 확산과 계층화(stratification)방식에 의해 높은 위험성을 유발시키고 있다. 이러한 가스의 누출확산사고들과 일반적인 가스누출사고들의 비교는 그 사실들을 증명해주고 있다. 이런 사실에 의해 위험한 가스확산에 대한 실험과 고유특성을 고려한 확산모델의 개발이 여러 관점에서 진행되고 있으며, 이들의 중요성은 이미 세계적으로 의미를 부여하고 있다.(중략)

• Journal of the Korean Institute of Gas
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• v.3 no.2 s.7
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• pp.43-52
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• 1999

An experimental chamber was fabricated to observe the gas diffusion behavior of leak gas from underground city-gas pipeline. It was made of acryl so that feeding of gas and the measuring points of the gas could be varied in each experiment. The MOS sensors were used to measure the concentrations of leak gas. The soil media such as the Jumunjin standard sand and the granite weathered soil were used to measure the gas diffusion and the change of leak gas concentrations was measured with time for various gas flow rate. As the distance between the leak point of gas and the measuring point of MOS sensor decreases, or the leak rate increases, the detection time of gas at a measuring points decreases and the gas concentration increases quickly and the concentration of the gas at steady state also increases. As the density of granite weathered soil is higher than that of Jumunjin standard sand for compaction, the detection time of leak gas in the granite weathered soil was longer than that in the Jumunjin standard soil. The leak gas concentrations in the granite weathered soil were lower than those in the Jumunjin standard sand at the beginning of gas leaking from a pipe, but inverse phenomenon was occured at steady state.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.1074-1077
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• 2011

국내외 대규모 산업시설은 유해물질과 직 간접적으로 밀접하게 관련되어 유해물질 누출사고는 막대한 물적, 인적 피해를 발생시키며 누출물질, 저장시설, 대기 상태에 따라 유해물질 확산 속도 및 범위가 다르기 때문에 이를 예측하는 대기확산 시스템이 필요하다. 또한 기존의 대기확산 시스템은 산업시설 구조물 설계 단계에서 안전성을 확인하는 시뮬레이션용으로 사용되었기 때문에 누출사고 발생 시 즉각적인 처리와 대응이 어려우며 전문적 지식수준의 사용자 입력을 요구한다. 본 논문은 에너지 플랜트 환경의 특수성과 효율성을 고려하여 운영 중인 시설에 적용 가능한 대기확산 시스템 연구를 목적으로 한다. 이를 위하여 신속하고 효율적인 대기확산 모델을 선정 정의하고 융통성 있는 대기확산 시스템의 구성요소를 컴포넌트화하여 구현하였으며 사고 발생 시 빠르게 피해범위를 예측할 수 있는 실시간 대기확산 시스템 설계 방안을 제시하였다.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2000.06a
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• pp.180-185
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• 2000

연료로 사용하는 가연성 가스의 양이 증가함에 따라 가스 사고 건수도 증가하고 있으며 가스사고 중 약 35% 정도가 가스의 누설사고였다. 이러한 가스의 누설사고는 일정시간 경과 후 적절하게 배출되지 못할 경우 화재나 폭발사고로 이어질 위험성이 매우 크다. 즉 가스의 누출은 폭발이나 연소의 3요소 중에서 가연물이 제공되는 과정으로 가스폭발사고나 화재를 예방하기 위해서는 근본적으로 가스의 누출을 방지해야 한다. (중략)

• Journal of the Korean Institute of Gas
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• v.16 no.1
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• pp.15-21
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• 2012

An analysis was completed of the hazards distance of hydrogen accidents such as jet release, jet fire, and vapor cloud explosion(VCE) of hydrogen gas, and simplified equations have been proposed to predict the hazard distances to set up safety distance by the gas dispersion, fire, and explosion following hydrogen gas release. For a small release rate of hydrogen gas, such as from a pine-hole, the hazard distance from jet dispersion is longer than that from jet fire. The hazard distance is directly proportional to the pressure raised to a half power and to the diameter of hole and up to several tens meters. For a large release rate, such as from full bore rupture of a pipeline or a large hole of storage vessel, the hazard distance from a large jet fire is longer than that from unconfined vapor cloud explosion. The hazard distance from the fire may be up to several hundred meters. Hydrogen filling station in urban area is difficult to compliance with the safety distance criterion, if the accident scenario of large hydrogen gas release is basis for setting up the safety distance, which is minimum separation distance between the station and building. Therefore, the accident of large hydrogen gas release must be prevented by using safety devices and the safety distance may be set based on the small release rate of hydrogen gas. But if there are any possibility of large release, populated building, such as school, hospital etc, should be separated several hundred meters.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.118-124
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• 2017

In this study, a numerical simulation was performed using commercial code Fluent(v.17.1). The underground Combined Cycle Power Plant (CCPP) was simplified to analyze the methane gas leakage with the crack size and position. In addition, extensive numerical simulations were carried out for different crack sizes from 10 mm to 20 mm. The crack position is the gas leakage, which is assumed to be near the pipe elbow and the gas turbine. A total of 4 cases were compared and analyzed. To analyze the gas leakage, the concept of the Lower Flammable Limit (LFL) was applied. The leakage distance was defined in the longitudinal direction, and the transverse direction was estimated and quantitatively analyzed. As a result, the leakage distance in the longitudinal direction varies by 52.3 % depending on the crack size at the same crack position. Moreover, the maximum difference was 34.8 % according to the crack position when the crack sizes are identical. As jet flow impacts on the obstacle and changes its direction, the recirculation flows are formed. These results are expected to provide useful data to optimize the location and number of gas detections in confined spaces, such as underground CCPP.

• Journal of the Korean Institute of Gas
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• v.2 no.2
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• pp.61-69
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• 1998

The risk assessments for gas leak in underground pipeline are conducted about the explosion accident of AHYUN-DONG underground service-base on December, 1994(Gaussian gas, LNG) and the accident of TAEGU subway on April 1995(Heavy gas LPG). We have calculated the total mass of gas release and have respected the efficient of explosions with report of the spot. The dispersion zones of LNG were calculated as large as fifteen times to those of LPG by ALOHA. The effects of thermal radiation from LNG explosion were assumed less than that from LPG by PHAST.

• Journal of the Korean Institute of Gas
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• v.16 no.4
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• pp.44-51
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• 2012

It is more important to realize safety management, medium-large accident prevention and risk prediction as accident of industry facilities can generate enormous physical and human damage because most energy plant might handle toxic substance. Especially, atmospheric dispersion system, which is able to simulate situation, have been used for release accident of toxic substance since the accident can show different of dispersion range and velocity according to release material, storage facility and atmospheric status. However those systems have been used generally in design step of industry facility and are difficult to deal with release accident quickly. Although some researches and cases have been studied for using real-time atmospheric information, there are insufficient system for processing quickly release accident. This paper aims to develop real-time smart atmospheric dispersion system that can deal with release accident quickly by enhancing distinct characteristics and efficiency of energy plant, and select release time and area using intelligent algorithm as accident prevention type.

• Journal of the Korean Institute of Gas
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• v.16 no.5
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• pp.58-65
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• 2012

Various models are currently applied to predict the dispersion of leaked combustible gas and overpressure from a vapor cloud explosion(VCE). However, those models use simple approaches where topography and barriers of anti-leakage facilities and the effects of buildings were not sufficiently taken into considerations. For this reason, this study has proposed the dispersion process of leaked gas, distribution patterns, and flames and overpressure generated from gas explosions in 2D and 3D virtual spaces by reviewing more accurately analyzable computational fluid dynamics (CFD) model by considering various variables including combustion types of leaked substances, geometry of facility, warm currents, barriers, the influence of wind, and others. The CFD analysis results are anticipated to be usefully applied for the risk analysis of explosion and for the risk-based design.

• Journal of the Korean Institute of Gas
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• v.17 no.2
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• pp.44-49
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• 2013

Due to rapid rise of consuming rate for natural gas, installation and operation of high pressure natural gas pipeline is inevitable for high rate of gas transportation. Accordingly incidents on the underground high pressure natural gas pipeline come from various reasons will lead to massive release of natural gas and gas dispersion in the air. Further, fire and explosion from ignition of released gas may cause large damage. This study is for release rate, dispersion and flash fire of natural gas to establish a safety management system, setting emergency plan and safety distance.