• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.220-223
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• 2008

A test facility to measure the performance of a KM(Kick Motor) is constructed, and prediction of blast wave propagation over the facility is performed to check if the safety of test personnel in MCC(Main Control Center) can be guaranteed even for the most severe explosion. Assuming that the initial explosion energy is contained in a sphere under the pressure of 500, 1000, 1500 psi, respectively, the radius of the sphere is determined for each pressure to set the mass of contained explosion gas to 35 kg. The material properties of explosion gas are set to be the ones of KM propellant combustion gas under normal condition. To reduce the effort and time required for a complex three-dimensional modeling, the flowfield is approximated to axismmetry. Calculations are performed for all three initial pressure conditions, and the analysis of the result is given for 1500 psi which is expected to be the worst case. The maximum pressure is 3.5 psig while the minimum pressure is -1.2 psig on the outer wall of MCC, and the maximum pressure difference between the inner and outer walls of protection wall amounts to 3.0 psi.

• Nuclear Engineering and Technology
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• v.48 no.1
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• pp.72-86
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• 2016

A steam explosion may occur during a severe accident, when the molten core comes into contact with water. The pressurized water reactor and boiling water reactor ex-vessel steam explosion study, which was carried out with the multicomponent three-dimensional Eulerian fuel-coolant interaction code under the conditions of the Organisation for Economic Co-operation and Development (OECD) Steam Explosion Resolution for Nuclear Applications project reactor exercise, is presented and discussed. In reactor calculations, the largest uncertainties in the prediction of the steam explosion strength are expected to be caused by the large uncertainties related to the jet breakup. To obtain some insight into these uncertainties, premixing simulations were performed with both available jet breakup models, i.e., the global and the local models. The simulations revealed that weaker explosions are predicted by the local model, compared to the global model, due to the predicted smaller melt droplet size, resulting in increased melt solidification and increased void buildup, both reducing the explosion strength. Despite the lower active melt mass predicted for the pressurized water reactor case, pressure loads at the cavity walls are typically higher than that for the boiling water reactor case. This is because of the significantly larger boiling water reactor cavity, where the explosion pressure wave originating from the premixture in the center of the cavity has already been significantly weakened on reaching the distant cavity wall.

• Korean Chemical Engineering Research
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• v.58 no.4
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• pp.610-617
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• 2020

In process installations, chemicals operate at high temperature and high pressure. Propylene is used as a basic raw material for manufacturing synthetic materials in the petrochemical industry; However, it is a flammable substance and explosive in the gaseous state. Thus, caution is needed when handling propylene. To prevent explosions, an inert gas, carbon dioxide, was used and the changes in the extent of explosion due to changes in pressure and oxygen concentration at 25 ℃, 100 ℃, and 200 ℃ were measured. At constant temperature, the increase in explosive pressure and the rates of the explosive pressure were observed to rise as the pressure was augmented. Moreover, as the oxygen concentration decreased, the maximum explosive pressure decreased. At 25 ℃ and oxygen concentration of 21%, as the pressure increased from 1.0 barg to 2.5 bar, the gas deflagration index (K_g) increased significantly from 4.71 barg·m/s to 18.83 barg·m/s.

• Journal of the Korean Society of Safety
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• v.7 no.3
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• pp.35-42
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• 1992

Ignition energy effects of concentration of mixed gas In closed cylindrical vessel(1, 832㎤) are studied. The ignition energy ranged from 25 Joule to 110 Joule, and hidrogen and methane gases were used for flammable gas at stoichiometric condition with oxygen gas and nitrogen gas (N2) was for inert gas, which concentration was maximum 60% . The explosion pressure, temperature, concentration of product gases were calculated. It is found that - The explosion pressure and explosion velocity increase with ignition energy. - The gradience of explosion velocity with ignition energy is steeper than explosion pressure. - The results of calculation are similiar with results of experiment. - NOx is not serious product gas for methane and hydrogen gas, but CO is serious at certain concentration for methane in asphyxiation.

• Journal of the Korean Society of Safety
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• v.19 no.4 s.68
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• pp.14-19
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• 2004

Boiler is a hazardous equipment to have potential explosion ail the time. And not only it has malfunction at explosion. it lead to people death but also secondary accident such as explosion and fire. Therefore, this equipment should not be broken for keeping its own function. And also, high level of safety should be kept in the process of the use not to be malfunctioned. A large scale of accident due to boiler explosion can be preventive in advance. Boiler fracture is occurred by instant expansion (approximately 1700 time) from quick evaporation of rater in boiler, due to pressure decrease in boiler Emitting energy from it is tremendous and it is so dangerous because of its high temperature. Secondary explosion such as fire is also a main hazard occurring at fuel supply place. If any devices with high pressure is broken, then not only boiler vessel but also components of it are spread with high speed, causing secondary accident. This study is to analyze integrally accident cause of fire and flue tube boiler to have occurred pressure fracture actually, to show countermeasures to prevent accident loss from the fire and flue tube boiler.

• Geomechanics and Engineering
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• v.28 no.3
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• pp.209-224
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• 2022

In this study, the numerical analysis model of π-beam explosion is established to compare and analyze the failure modes of the π-beam under the action of explosive loads, thus verifying the accuracy of the numerical model. Then, based on the numerical analysis of different protection forms of π beams under explosive loads, the peak pressure of π beam under different protection conditions, the law of structural energy consumption, the damage pattern of the π beam after protection, and the protection efficiency of different protective layers was studied. The testing results indicate that the pressure peak of π beam is relatively small under the combined protection of steel plate and aluminum foam, and the peak value of pressure decays quickly along the beam longitudinal. Besides, as the longitudinal distance increases, the pressure peak attenuates most heavily on the roof's explosion-facing surface. Meanwhile, the combined protective layer has a strong energy consumption capacity, the energy consumed accounts for 90% of the three parts of the π beam (concrete, steel, and protective layer). The damaged area of π beam is relatively small under the combined protection of steel plate and aluminum foam. We also calculate the protection efficiency of π beams under different protection conditions using the maximum spalling area of concrete. The results show that the protective efficiency of the combined protective layer is 45%, demonstrating a relatively good protective ability.

• Proceedings of the Safety Management and Science Conference
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• 2001.05a
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• pp.301-310
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• 2001

A study for the dangerous properties measurment of dust explosion was attended by the various dust concentration on Anthraquinone, Sodiumbenzoic acid, Corn starch, soy sauce powder, and cheese powder. As the result, maximum explosion pressure, the maximum rate of pressure rise, autoigntion temperature, and the water content of dust on lower limit explosion concentration was obtained as follows 1. The lower limit explosion concentration on soy sauce powder with the humidity of 65 to 90% increased by increasing the con tent of moisture, and the effect of dry air and moisture air decreased better in make of dry air. 2. The effect of a various dust concentration on autoigntion temperatures is investigated, If the vessel of dust explosion is small size and the easiness of autoignition was controled by air within the vessel, because it was better decreased air with increasing of dust concentration 3. The maximum explosion pressures of Anthraguinone, sodiumbenzoic acid, com starch, soy sauce powder, and cheese powder were 1.0g/$\ell$, 1.0g/$\ell$, 1.5g/$\ell$, 1.5g/$\ell$, and 1.5g/$\ell$, respectively, and the maximum rate of pressure rise were 0.5g/$\ell$, 0.5g/$\ell$, 1.0g/$\ell$, 1.0g/$\ell$, and 1.0g/$\ell$, respectively.

• Journal of the Korea Safety Management & Science
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• v.16 no.4
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• pp.185-191
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• 2014

In this study safety distance was investigated for small-scale LNG storage facilities in order to provide basic data for safety. The results are as follows; (1) For explosion pressure criteria, current criteria are reasonable, but water spray system should be recommended to LNG storage tank to ensure safety. (2) For criteria based on the results of the quantitative risk assessment, criteria applied to people are $5kW/m^2$ for radiation, LFL for dispersion, and 7kPa for explosion pressure. And criteria applied to facility are $37.5kW/m^2$ for radiation and 20 kPa for explosion pressure.

• Korean Chemical Engineering Research
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• v.58 no.3
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• pp.356-361
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• 2020

Propylene is widely used in petrochemical manufacturing at over 200 ℃. However, since propylene is a flammable gas with fire and explosion risks, inert nitrogen is injected to prevent them. In this study, experiments were conducted using propylene-nitrogen-oxygen upon pressure changes at 200 ℃. At 21% oxygen, as pressure increased from 0.10 MPa to 0.25 MPa, lower explosion limit (LEL) decreased from 2.2% to 1.9% while upper explosion limit (UEL) increased from 14.8% to 17.6%. In addition, minimum oxygen concentration (MOC) decreased from 10.3% to 10.0%, indicating higher risks with the expanded explosive range as pressure increased. With increase of pressure from 0.10 MPa to 0.25 MPa, explosion pressure increased from 1.84 MPa to 6.04 MPa, and the rate of rise of maximum explosion pressure increased drastically from 90 MPa/s to 298 MPa/s. It is hoped that these results can be used as basic data to prevent accidents in factories using propylene.

• Journal of the Korean Institute of Gas
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• v.3 no.3 s.8
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• pp.23-28
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• 1999

Variation of explosion characteristics by the blocks in closed vessel was investigated to analyse the effect of the block volume(volume blockage) and the surface area of the blocks(ratio of block surface area to vessel volume). Volume and surface area of blocks in explosion vessel were changed by the combination of blocks. The volume of explosion vessels was 270 liter, and the LPG-air or NG-air mixtures were ignited by the electric spark. Explosion pressure was measured with the strain type pressure transducer. From the experimental results, explosion pressure was decreased by the increase of the volume blockage and the block surface area. And the decrease of explosion pressure was more affected by the volume blockage than the surface area.