• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.1
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• pp.1-8
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• 2021

Vapor cloud explosions show different characteristics from that caused by ordinary TNT explosives and their loading effect is similar to pressure waves. Typical methods used for blast pressure calculations are the TNT-equivalent method and multi-energy method. The TNT-equivalent method is based on shock waves, similar to a detonation phenomenon, and multi-energy method is based on pressure waves, similar to a deflagration phenomenon. This study was conducted to derive an appropriate blast pressure by applying various plant explosion cases. SDOF analysis and nonlinear dynamic analysis were performed to compare the degree of deformation and damage of the selected structural members for the explosion cases. The results indicated that the multi-energy method was more exact than the TNT-equivalent method in predicting the blast pressure of vapor cloud explosions. The blast pressure of vapor cloud explosion in plants can be more accurately calculated by assuming the charge strength of multi-energy method as 7 or 8.

• Journal of the Korean Institute of Gas
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• v.20 no.3
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• pp.30-37
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• 2016

Electrical apparatuses for use in the presence of flammable gas atmospheres have to be specially designed to prevent them from igniting the explosive gas. Flameproof design implies that electrical components producing electrical sparks are contained in enclosures and withstand the maximum pressure of internal gas or vapours. In addition, any gaps in the enclosure wall have to designed in such a way that they will not transmit a gas explosion inside the enclosure to an explosive gas or vapours atmosphere outside it. In this study, we explained some of the most important physical mechanism of MESG(Maximum Experimental Safe Gap) that the jet of combustion products ejected through the flame gap to the external surroundings do not have an energy and temperature large enough to initiate an ignition of external gas or vapours. We measured the MESG and maximum explosion pressure of ternary gas mixtures(propane-acetylene-air) by the test method and procedure of IEC 60079-20-1:2010. As a result, the composition of propane gas that has lower explosive power than acetylene gas in the ternary gas mixtures makes greater effects on MESG and explosion pressure.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.208-211
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• 2007

Separation Devices have two functions. These two functions are to bond and to separate two bodies. This paper is about separation devices which use explosives to separate their bodies. Explosive bolt is separated with two bodies when the explosives in the body detonated. The good things of explosive bolt are that it has simple operational system and it is made of few parts. But it has side effects; fragment and pyre-shock. To avoid these side effects gas expansion separation(GES) bolt and pressure cartridge actuation separation(PAS) devices are invented. These use pressure to separate their bodies. The pressure is generated when explosives are burned. But the sizes of PAS devices are bigger than explosive bolts. And GES bolt has a mechanically lower bonding ability than that of explosive bolt. When you design separation devices, it is recommended to know operational system and characteristics of separation devices, to design best one.

• Journal of the Korean Institute of Gas
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• v.10 no.3 s.32
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• pp.60-64
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• 2006

Explosion range and explosion characteristics of by product gas from carbon black manufacturing process were studied. About 75% of the by product gas were composed with water vapour and nitrogen. And the combustible component in the gas were hydrogen, methane, acetylene and carbon mono-oxide. Because of the combustible components in the by product gas there are explosion hazards in the gas handling process. Explosion range of the gas by experiment was from 17.1% to 70.7% and the value has considerable difference with the calculated value from Lechatelier law. Explosion pressure of the gas was $5.4kg/cm^2$ and the average explosion pressure rise rate was $39.2kg/cm^2/s$. Based on the experimental result we can expect that a explosion or fire accident during the handling the gas can make a severe loss, therefore there should be a explosion prevention or protection measures in the gas handling process.

• Korean Chemical Engineering Research
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• v.54 no.3
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• pp.367-373
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• 2016

Many of plastic powders handled in industry are combustible and have the hazard of dust fire and explosion accidents. However poor information about the safe handling has been presented in the production works. The aim of this research is investigated experimentally on explosive characteristics of various plastic powders used in industry and to provide additional data with safety informations. The explosibility parameters investigated using standard dust explosibility test equipment of Siwek 20-L explosion chamber. As the results, the dust explosion index ($K_{st}$) of ABS ($209.8{\mu}m$), PE ($81.8{\mu}m$), PBT ($21.3{\mu}m$), MBS ($26.7{\mu}m$) and PMMA ($14.3{\mu}m$) are 62.4, 59.4, 70.3, 303 and 203.6[$bar{\cdot}m/s$], respectively. And flame propagation velocity during plastic dust explosions for prediction of explosive damage was estimated using a flame propagation model based on the time to peak pressure and flame arrival time in dust explosion pressure assuming the constant burning velocity.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.2
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• pp.187-195
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• 2015

The gas explosions in offshore installations are known to be very severe according to its geometry and environmental conditions such as leak locations and wind directions, and a dynamic response of structures due to blast loads depends on the load profile. Therefore, a parametric study has to be conducted to investigate the effects of the dynamic response of structural members subjected to various types of load shapes. To do so, a series of CFD analyses was performed using a full-scale FPSO topside model including detail parts of pipes and equipments, and the time history data of the blast loads at monitor points and panels were obtained by the analyses. In this paper, we focus on a structural dynamic response subjected to blast loads changing the magnitude of positive/negative phase pressure and time duration. From the results of linear/nonlinear transient analyses using single degree of freedom(SDOF) and multi-degree-of freedom(MDOF) systems, it was observed that dynamic responses of structures were significantly influenced by the magnitude of positive and negative phase pressures and negative time duration.

• Korean Chemical Engineering Research
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• v.62 no.1
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• pp.27-35
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• 2024

Fuel gases such as methane and propane are used in explosion hazardous area of domestic plants and can form non-uniform mixtures with the influence of process conditions due to leakage. The fire-explosion risk assessment using literature data measured under uniform mixtures, damage prediction can be obtained the different results from actual explosion accidents by gas leaks. An explosion characteristics such as explosion pressure and flame velocity of non-uniform gas mixtures with concentration change similar to that of facility leak were examined. The experiments were conducted in a closed 0.82 m long stainless steel duct with observation recorded by color high speed camera and piezo pressure sensor. Also we proposed the quantification method of non-uniform mixtures from a regression analysis model on the change of concentration difference with time in explosion duct. For the non-uniform condition of this study, the area of flame surface enlarged with increasing the concentration non-uniform in the flame propagation of methane and was similar to the wrinkled flame structure existing in a turbulent flame. The time to peak pressure of methane decreased as the non-uniform increased and the explosion pressure increased with increasing the non-uniform. The ranges of K_G (Deflagration index) of methane with the concentration non-uniform were 1.30 to 1.58 [MPa·m/s] and the increase rate of K_G was 17.7% in methane with changing from uniform to non-uniform.

• Bulletin of the Korean Institute for Industrial Safety
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• v.1 no.1
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• pp.11-16
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• 2001

과학과 산업의 발전에 따라 공정안전기술도 새롭게 발전되어 가고 있음에도 불구하고 공정산업에서의 폭발사고가 자주 발생하고 있으며, 사고가 발생할 경우 대규모의 인명 덴 재산 손실을 초래하여 왔다. 우리나라의 경우 화학장치 산업이 1960년대 시작되어 많은 부분들이 교체되어야 할 주기를 지났거나 교체해야 할 상태에 있고, 이에 따라 신설 또는 증설공사 등으로 폭발위험성이 높은 것으로 보고되고 있다. 화학공정에는 가연성 위험물이나 폭발성 물질들이 대량으로 취급되고 있기 때문에 비록 적은 공정이라도 화재나 폭발이 발생하면 대규모의 피해를 초래한다. 특히 화학공정산업에서 사고로 발생하는 손실의 2/3 이상이 폭발사고에 의한 것으로 보고되고 있다. 즉 총 손실의 약 75%가 폭발사고에 의한 것이며 약 20%가 화재이고 나머지는 독성과 관련된 것으로 나타나 있다. 화학공정에서의 폭발 사고에 의한 피해 관련정보는 많은 자료에 의해 보고되고 있다. 실제로 막대한 파괴와 인명손실을 가져오는 과압은 일반적으로 폭발에서 발생되는 최대 압력인 6-8kg/$\textrm{cm}^2$ 보다도 훨씬 낮다.(중략)

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.404-407
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• 2010

본 논문에서는 비선형 동적 해석 프로그램인 AUTODYN을 이용해 기둥의 단면 형상의 변화에 따른 폭발 하중의 영향을 분석하였다. 먼저 폭발하중 산정의 타당성을 확인하기 위해 AUTODYN을 이용한 예제해석을 수행하였으며, 폭발하중에 의한 영향을 가장 효율적으로 확인할 수 있는 인자인 압력을 비교하였다. 이를 토대로 기둥 형상에 따른 폭발 저항 성능을 평가하기 위해 같은 단면적과 높이를 갖는 정사각형과 원형 기둥을 모델링 한 후 TNT의 양에 따른 폭발전후의 부피를 비교하였다. 해석결과를 비교해보면 정사각형기둥이 원형기둥보다 폭발에 대한 손상정도는 더 크지만 기둥이 절단되지 않도록 하는 저항성능이 더 우수한 것을 확인할 수 있었다. 비록 철근의 영향을 고려하지 않았지만, 이와 같은 결과를 통해 TNT의 양에 따른 기본적인 폭발거동과 대테러 설계를 위한 기둥 단면 선택시 기초적인 자료로 활용가능 할 것으로 사료된다.

• Journal of the Korean Institute of Gas
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• v.27 no.4
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• pp.56-61
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• 2023

The plant is an important facility as a infrastructure, and ensuring safety against possible accidents such as gas leaks and explosions must be considered in the design. However, there is little study on explosion pressure in plants for reasons such as economic feasibility, and overpressure data on this field is insufficient. In this study, an experimental design plan considering the explosion scenario that may occur in the plant was presented, and the explosion pressure was confirmed through an explosion experiment. Hydrogen-methane mixed gas was used as a combustible material, and the effect of confinement and congestion on overpressure was studied. The effect of overlapping pressure waves during deflagration and the turbulence effect by congested pipes are discussed. The results of this study can be used as input data in various safety designs.