• Title/Summary/Keyword: Overpressure

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Probabilistic Assesment of the Effects of Vapor Cloud Explosion on a Human Body (증기운 폭발이 인체에 미치는 영향에 대한 확률론적 평가)

  • Yoon, Yong-Kyun;Ju, Eun-Hye
    • Tunnel and Underground Space
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    • v.31 no.1
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    • pp.52-65
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    • 2021
  • In this study, authors analyzed the vapor cloud explosion induced by propane leak at the PEMIX Terminal, which is the propane storage facility outside of Mexico City. TNT equivalence mass for the leaked 4750 kg propane was estimated to be 9398 kg. Blast parameters such as peak overpressure, positive phase duration, and impact at 40-400 (m) away from the center of the explosion were calculated by applying TNT Equivalency Method and Multi-Energy Method. The probability of damage due to lung damage, eardrum rupture, head impact, and whole-body displacement impact by applying the probit function obtained using blast parameters was evaluated. The peak overpressure obtained using Multi-Energy Method was found to be greater than the peak overpressure obtained by applying the TNT Equivalency Method at all distances considered, but it was evaluated that there was no significant difference from the points above 200 m. The peak overpressure obtained by Multi-Energy Method was computed to assess the extent of damage to the structure, and it was shown that structures within 100 m of the explosion center would collapse completely, and that the glasses of the structures 400 m away would be almost broken. The probability of death due to lung damage was shown to vary depending on a human body's position located in the propagating direction of shock wave, and if there is a reflecting surface in the immediate surroundings of a human body, the probability of death was estimated to be the greatest. The impact of shock wave on lung damage, eardrum rupture, head impact, and whole-body displacement impact was evaluated and found to affect whole-body impact < lung damage < eardrum rupture

Damage Evaluation of Adjacent Structures for Detonation of Hydrogen Storage Facilities (수소저장시설의 폭발에 대한 인접 구조물의 손상도 평가)

  • Jinwon Shin
    • Journal of Korean Society of Disaster and Security
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    • v.16 no.1
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    • pp.61-70
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    • 2023
  • This study presents an analytical study of investigating the effect of shock waves generated by the hydrogen detonation and damage to structures for the safety evaluation of hydrogen storage facilities against detonation. Blast scenarios were established considering the volume of the hydrogen storage facility of 10 L to 50,000 L, states of charge (SOC) of 50% and 100%, and initial pressures of 50 MPa and 100 MPa. The equivalent TNT weight for hydrgen detonation was determined considering the mechanical and chemical energies of hydrogen. A hydrogen detonation model for the converted equivalent TNT weight was made using design equations that improved the Kingery-Bulmash design chart of UFC 3-340-02. The hydrogen detonation model was validated for overpressure and impulse in comparison to the past experimental results associated with the detonation of hydrogen tank. A parametric study based on the blast scenarios was performed using the validated hydrogen detonation model, and design charts for overpressure and impulse according to the standoff distance from the center of charge was provided. Further, design charts of the three-stage structural damage and standoff distance of adjacent structures according to the level of overpressure and impact were proposed using the overpressure and impulse charts and pressure-impulse diagrams.

Impact Range Analysis of Small LPG Storage Tank Explosions at Highway Rest Areas (고속도로 휴게소 소형 LPG 저장탱크 폭발에 따른 영향범위 분석)

  • Seung duk Jeon;Soon Beom Lee;Jai Young Lee
    • The Journal of the Convergence on Culture Technology
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    • v.9 no.6
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    • pp.319-327
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    • 2023
  • This study analyzes the risks of explosions of small LPG storage tanks installed at highway rest areas. For this purpose, the ranges of the effect of thermal radiation and overpressure caused by the BLEVE(Boiling Liquid Expansion Vapor Explosion)and VCE(Vapor Cloud Explosion) of a 2900-kg small LPG storage tank installed at highway rest areas were quantitatively evaluated by applying the Areal Location of Hazardous Atmospheres program. The ranges of influence of the derived explosion overpressure and thermal radiation were found to have a maximum radii of 336 m and 423 m, respectively. The study determined that those within 269 m could be severely injured by an explosion overpressure of 3.5 psi, and fatalities from thermal radiation of 10 kw/m2 could occur within 192 m of the exploded storage tank. The safety management plan for the LPG storage tank was discussed while considering the auxiliary facilities of highway rest areas and the extent of the damage impact. These research results will help improve safety accident prevention regulations considering the environment and facilities of the rest areas as well as the safety management of small LPG storage tanks installed at highway rest areas.

Study on the Empirical Equations for Pressure Curve by Air Blast (폭발파에 의한 폭발압력곡선 경험식에 관한 연구)

  • Kwon, Sangki
    • Explosives and Blasting
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    • v.35 no.1
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    • pp.1-17
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    • 2017
  • The understanding of the pressure associated with air blast, which travels through air, and its effect on surface and underground structures is highly important. It is necessary to determine the pressure change with time and distance for a computer simulation of the explosion impact on a structure. From the previous studies, many empirical equations for estimating the parameters related to the pressure change. In this study, the empirical equations for predicting peak overpressure, duration of positive phase, impulse, minimum negative pressure, duration of negative pressure, arrival time, and decay constant were reviewed and analyzed. Also, the pressure changes predicted from the Kingery equation, which is the most commonly used, and from the other empirical equations were compared.

A Study on the Overpressure Estimation of BLEVE (BLEVE로 인한 과압 예측에 관한 연구)

  • Kim In-Tae;Kim In-Won;Song Hee-Oeul
    • Journal of the Korean Institute of Gas
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    • v.4 no.1 s.9
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    • pp.69-76
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    • 2000
  • Explosion Quantities and flashing mass resulting from the variation of temperature are calculated by a computer program, BLEVE ESTIMATOR, to carry out the risk assessment of BLEVE. The damages caused by the BLEVE are estimated under the explosion of the simulation condition similar to the Puchun LP gas station accident, and the results are compared with the commercial program SAFER of Dupont CO. Explosion quantities and flashing mass increase exponentially with the increase of explosion temperature. These values for propane are relatively higher than those for n-butane. In conditions of higher vessel temperature, vessel pressure, and liquid ratio of containment, higher overpressures are calculated.

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Computational and Analytical Studies on the Impulse Wave Discharged from the Exit of a Pipe (관출구로부터 방출하는 펄스파에 대한 수치계산과 해석적 연구)

  • Lee, D.H.;Kim, H.S.;Kim, H.D.
    • Proceedings of the KSME Conference
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    • 2001.11b
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    • pp.432-437
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    • 2001
  • A computational work of the impulse wave which is discharged from the open end of a pipe is compared to the Lighthill's aeroacoustics theory. The second-order total variation diminishing(TVD) scheme is employed to solve the axisymmetric, compressible, unsteady Euler equations. The relationship between the initial compressure wave form and the resulting impulse wave is characterized in terms of the peak pressure. The overpressure, pressure gradient and wavelength of the initial compression wave are changed to investigate the influence of the initial compressure wave form on the peak pressure of impulse wave. The results obtained show that for the initial compression wave of a large wavelength and small pressure gradient the peak pressure of the impulse wave depends upon the wavelength and pressure gradient of compression wave, but for the initial compression wave of a short wavelength and large pressure gradient the peak pressure of the impulse wave is almost constant regardless of the wavelength and pressure gradient of compression wave. The peak pressure of the impulse wave is increased with an increase in the overpressure of the initial compression wave. The results from the numerical analysis are well compared to the results from the aeroacoutics theory with a good agreement.

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A Study on the Characteristics of the Impulse Wave Discharged from the Exit of a Pipe (관출구로부터 방출하는 펄스파 특성에 관한 연구)

  • 이동훈;김희동;이명호;박종호
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.12 no.1
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    • pp.48-56
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    • 2002
  • A computational work of the impulse wave which is discharged from the open end of a pipe is compared to the Lighthill\`s aeroacoustics theory. The second-order total variation diminishing(TVD) scheme is employed to solve the axisymmetric, compressible, unsteady Euler equations. The relationship between the initial compressure wave form and the resulting impulse wave is characterized in terms of the peak pressure. The overpressure, pressure gradient and wavelength of the initial compression wave are changed to investigate the influence of the initial compressure wave form on the peak pressure of impulse wave. The results obtained show that for the initial compression wave of a large wavelength and small pressure gradient the peak pressure of the impulse wave depends upon the wavelength and pressure gradient of compression wave, but for the initial compression wave of a short wavelength and large pressure gradient the peak pressure of the impulse wave is almost constant regardless of the wavelength and pressure gradient of compression wave. The peak pressure of the impulse wave is increased with an increase in the overpressure of the initial compression wave. The results from the numerical ana1ysis are well compared to the results from the aeroacoutics theory with a food agreement.

Reduction of Thermal Radiation from Flare Stack by Flare Gas Recovery Unit (폐가스 회수장치를 이용한 플레어스택의 복사열 감소)

  • Lee, Heon-Seok;Lee, Dong-Heuk;Yoo, Jin-Hwan;Park, Chul-Hwan;Ko, Jae-Wook
    • Journal of the Korean Institute of Gas
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    • v.15 no.1
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    • pp.40-45
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    • 2011
  • During process operations, overpressure can be caused by operator's error or malfunction of the device. To prevent this overpressure, gas was released through blowdown system. Because most of released gases are the hydrocarbon mixture and have flammable and toxic properties, the gas is released after burning in flare stack. The increase of scale and complexity of plant requires higher or additional flare stacks. This study tried to solve this problem through flare gas recovery system.

Experience for Development and Capacity Certification of Safety Relief Valves (안전방출밸브 개발과 용량인증 사례)

  • Kim, Chil-Sung;Roh, Hee-Seon;Kim, Kang-Tae;Kim, Ji-Heon;Kim, Jong-Su
    • The KSFM Journal of Fluid Machinery
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    • v.8 no.3 s.30
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    • pp.16-25
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    • 2005
  • The purpose of this study is localization of safety relief valves for Nuclear Service. The safety relief valve is the important equipment used to protect the pressure vessel, the steam generator and the other pressure facility from overpressure by discharging the operating medium when the pressure of system is reaching the design pressure of the system. We developed design technology used FEM ' CFM about safety relief valve for Nuclear Service according to ASME (or KEPIC) Code and KHNP's Technical Specification. To prove validity of a design technology, actually, we manufactured and inspected and tested the sample products designed according to a developed technology. The capacity qualification test was achieved according to requirement of ASME(or KEPIC) Code by NBBI and the functional qualification test was achieved according to ASME QME-1 for operating condition in technical specification of KHNP by NLI. Therefore we have to achieve the development of safety relief valves for Nuclear Service with our own technologies.

Study on the Quantitative Rod Internal Pressure Design Criterion (정량적인 핵연료봉 내압 설계기준에 관한 연구)

  • Kim, Kyu-Tae;Kim, Oh-Hwan;Han, Hee-Tak
    • Nuclear Engineering and Technology
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    • v.23 no.4
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    • pp.363-373
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    • 1991
  • The current rod internal pressure criterion permits fuel rods to operate with internal pressures in excess of system pressure only if internal overpressure does not cause the diametral gap enlargement. In this study, the generic allowable internal gas pressure not violating this criterion is estimated as a function of rod power. The results show that the generic allowable internal gas pressure decreases linearly with the increase of rod power. Application of the generic allowable internal gas pressure for the rod internal pressure design criterion will result in the simplication of the current design procedure for checking the diametral gap enlargement caused by internal overpressure because according to the current design procedure the cladding creepout rate should be compared with the fuel swelling rate at each axial node at each time step whenever internal pressure exceeds the system pressure.

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