• 한국화재소방학회논문지
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• 제23권5호
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• pp.50-56
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• 2009

폭발한계와 최소자연발화온도는 가연성 물질의 화재 및 폭발 위험성을 결정하는데 중요한 특성으로 이용된다. 에틸렌의 안전한 취급을 위해 에틸렌의 폭발한계와 최소자연발화온도를 고찰하였다. 에틸렌의 폭발하한계와 상한계는 공기 중에서 각 각 2.6vol%와 36vol%를 추천하며, 최소자연발화온도는 전면 가열인 경우는 $420^{\circ}C$, 국소 고온표면인 경우는 약 $800^{\circ}C$를 추천한다. 또한 에틸렌의 폭발한계의 온도 및 압력의 존성에 대한 새로운 예측식을 제시하였으며, 제시된 식에 의한 예측값은 문헌값과 일치하였다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 추계 학술발표회논문집
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• pp.13-19
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• 2003

Discriminant method using seismic signal was studied for discrimination of surface explosion. By means of the seismic spectral characteristics, multi-variate discriminant analysis was performed. Four single discriminant techniques - Pg/Lg, Lg1/Lg2, Pg1/Pg2, and Rg/Lg - based on seismic source theory were applied to explosion and earthquake training data sets. The Pg/Lg discriminant technique was most effective among the four techniques. Nevertheless, it could not perfectly discriminate the samples of the training data sets. In this study, a compound linear discriminant analysis was defined by using common characteristics of the training data sets for the single discriminants. The compound linear discriminant analysis was used for the single discriminant as an independent variable. From this analysis, all the samples of the training data sets were correctly discriminated, and the probability of misclassification was lowered to 0.7％.

• 한국안전학회지
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• 제17권4호
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• pp.126-132
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• 2002

By using the reference data, the empirical equations which describe the interrelationships of explosion properties and physical properties of n-chlorinated hydrocarbons have been derived. The properties which have been correlated are the lower and upper explosive limits, the stoichiometric coefficients, the heats of combustion, the carbon numbers. Also, the new equations using the mathematical and statistical methods for predicting the temperature dependence of lower explosive limits(LEL) of chlorinated hydrocarbons on the basis of the literature data are proposed. The fire and explosion properties calculated by the proposed equations in this research were a good agrement with literature data within a few A.A.P.E.(Average Absolute Percent Error) and A.A.D.(Average Absolute Deviation.) From a given explosive properties, by using the proposed equations, it is possible to predict to the fire and explosion characteristics for the other chlorinated hydrocarbons.

• 한국자동차공학회논문집
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• 제15권1호
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• pp.49-55
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• 2007

The characteristics of auto-ignition and combustion process of a single droplet of emulsified fuel suspended in a high-temperature air chamber have been investigated experimentally with various droplet sizes, surrounding temperatures, and water contents. The used fuels was n-Decane and it was emulsified with varied water contents whose maximum is 30%. The high-speed camera has been adopted to measure the ignition delay and flame life time. It was also applied to observe micro-explosion behaviors. The increase of droplet size and chamber temperature cause the decrease of the ignition delay time and flame life-time. As the water contents increases, the ignition delay time increases and the micro-explosion behaviors are strengthened. The starting timings of micro-explosion and fuel puffing are compared for different droplet sizes and the amount of water contents.

• 화약ㆍ발파
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• 제41권3호
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• pp.73-92
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• 2023

가스 폭발의 위험성의 증대와 함께 가스 폭발의 규모와 영향을 예측하는데 필요한 폭발 인자들을 간접적으로 추정하는 방법들이 사용되고 있다. 본 연구에서는 주로 사용되고 있는 TNT 등가량 산정법, TNO 다중에너지 방법, BST 방법의 특성과 폭발 인자를 결정하는 과정을 비교하였다. TNT 등가량 산정법의 경우, 증기운 폭발의 형태와 폭발 물질 등 다양한 조건에 따라 적합한 efficiency factor를 선택하는 것이 필요하였다. TNO 다중에너지 방법은 클래스 번호를 결정하기 위한 객관적 기준이 부족하였으며 음의 과압을 추정하지는 못하였다. 기 보고된 인자값에 오기재로 보이는 부분을 확인하였으며 수정된 인자값을 제시하였다. BST 방법은 음의 과압을 포함한 보다 상세한 폭발 인자 추정이 가능하지만 사용하는 그래프가 가시적이지 않은 문제점이 있었다. 이를 보완하기 위해 그래프를 재작성하였으며 향후 그래프의 수식화를 통한 편리한 폭발 인자 추정이 가능할 것으로 기대된다.

• Korean Chemical Engineering Research
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• 제61권1호
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• pp.80-88
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• 2023

저밀도 폴리에틸렌(Low-density polyethylene, LDPE)은 분진폭발 관련 특성치에 대한 기준이 제시되고 있지 않아 제조 및 취급설비의 안전한 설계가 어렵다. 이 연구에서는 LDPE 제조공정 중 Bag Filter에서 채취한 분진(LDPE 1)과 Silo 등의 설비 외부에 누설된 퇴적 분진(LDPE 2)에서 채취한 2개 시료에 대하여 분진폭발 시험을 수행하였고 그 중 LDPE 2 분진에 대하여 요약하였다. 입도분석 결과, 체적기준 평균입경은 95.04 ㎛, 수밀도는 0~1 ㎛로 나타났다. 최대폭발압력(P_max)은 6.6 bar, 최대폭발압력상승속도는 1500 g/m³에서 366 [bar/s]로 분진폭발지수(K_st)는 99.4 bar·m/s로 ST-1 등급임을 확인하였다. 또한, 최소점화에너지는 10 mJ이며 최소점화온도는 450 ℃로 나타났다. 현재, 제조 및 취급 설계는 고밀도 폴리에틸렌(HDPE)의 특성값을 기초로 한다. 그러나, 시험 결과 LDPE 2 분진이 HDPE(입자지름 61.6 ㎛)보다 위험성이 높은 것으로 나타나 LDPE 제조공정에서 HDPE 설계기준을 적용할 때는 주의가 필요하다.

• Korean Chemical Engineering Research
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• 제62권1호
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• pp.27-35
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• 2024

메탄, 프로판 등을 주성분으로 하는 연료가스는 폭발위험장소에서 사용될 수 있으며, 누출로 인한 공정조건의 영향으로 불균일한 혼합기를 형성할 수 있다. 균일한 혼합기를 대상으로 측정된 문헌 데이터를 이용한 화재 폭발 위험성 평가, 손상 예측은 가스 누출에 의한 실제 폭발 사고와 다른 결과를 얻을 수 있다. 본 연구에서는 가스 누출시 나타날 수 있는 농도 변화에 있어서 불균일성 혼합기의 폭발압력, 화염속도 등의 폭발특성을 조사하였다. 길이 0.82 m의 스테인리스 재질의 밀폐 배관에서 수행하였으며 컬러 초고속 카메라 및 압력 센서를 사용하여 관찰하였다. 또한 배관 내의 시간에 따른 농도차이 변화에 대해 회귀분석 모델을 사용하여 불균일 혼합물의 정량화 방법을 제안하였다. 본 연구의 농도 불균일성 조건에 있어서 메탄 폭발 시 전파화염은 불균일성 농도가 높아짐에 따라 화염 면적의 증가가 관찰되었고 이는 난류 화염의 주름진 화염 구조와 유사하였다. 메탄의 최대압력까지 걸리는 소요시간은 불균일성이 클수록 감소하였고, 폭발압력은 불균일성이 클수록 증가하였다. 농도가 불균일한 메탄의 K_G(폭연지수)의 범위는 1.30~1.58 [MPa·m/s]으로서 메탄의 농도가 균일성에서 불균일성로 변화하면서 17.7% 증가하였다.

• 한국안전학회지
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• 제32권5호
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• pp.25-31
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• 2017

The flash point, explosion limits, autoignition temperature(AIT) are important combustible properties which need special concern in the chemical safety process that handle hazardous substances. For the evaluation of the flammable properties of n-butylacetate, this study was investigated the explosion limits of n-butylacetate in the reference data. The flash points, fire points and AIT by the ignition delay time of n-butylacetate were experimented. The lower flash points of n-butylacetate by using the Setaflash and Pensky-Martens closed-cup testers were $24^{\circ}C$ and $26^{\circ}C$, respectively. The flash points of n-butylacetate using the Tag and Cleveland open cup testers are measured $31^{\circ}C$ and $40^{\circ}C$, respectively. And the fire points of n-butylacetate by the Tag and Cleveland open cup testers were measured $32^{\circ}C$ and $41^{\circ}C$. The AIT of n-butylacetate measured by the ASTM 659E tester was measured as $411^{\circ}C$. The lower explosion limit of lower flash point $24^{\circ}C$, which was measured by the Setaflash tester, was calculated to be 1.40 vol%. Also, the upper explosion limit of upper flash point $67^{\circ}C$ the Setaflash tester was calculated to be 12.5 vol%.

• 대한조선학회논문집
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• 제57권6호
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• pp.322-330
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• 2020

This study deals with underwater explosion (UNDEX) characteristics of various non-explosive underwater shock sources for the development of non-explosive underwater shock testing devices. UNDEX can neutralize ships' structure and the equipment onboard causing serious damage to combat and survivability. The shock proof performance of naval ships has been for a long time studied through simulations, but full-scale Live Fire Test and Evaluation (LFT&E) using real explosives have been limited due to the high risk and cost. For this reason, many researches have been tried to develop full scale ship shock tests without using actual explosives. In this study, experiments were conducted to find the characteristics of the underwater shock waves from actual explosive and non-explosive shock sources such as the airbag inflators and Vaporizing Foil Actuator (VFA). In order to derive the empirical equation for the maximum pressure value of the underwater shock wave generated by the non-explosive impact source, repeated experiments were conducted according to the number and distance. In addition, a Shock Response Spectrum (SRS) technique, which is a frequency-based function, was used to compare the response of floating bodies generated by underwater shock waves from each explosion source. In order to compare the magnitude of the underwater shock waves generated by each explosion source, Keel Shock Factor (KSF), which is a measure for estimating the amount of shock experienced by a naval ship from an underwater explosionan, was used.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권4호
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• pp.346-352
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• 2005

The chemical characteristics, enzymatic saccharification, and ethanol fermentation of autohydrolyzed lignocellulosic material that was exposed to steam explosion were investigated using bagasse as the sample. The effects of the steam explosion on the change in pH, organic acids production, degrees of polymerization and crystallinity of the cellulose component, and the amount of extractive components in the autohydrolyzated bagasse were examined. The steam explosion decreased the degree of polymerzation up to about 700 but increased the degree of crystallinity and the micelle width of the cellulose component in the bagasse. The steam explosion, at a pressure of 2.55 MPa for 3 mins, was the most effective for the delignification of bagasse. 40 g/L of glucose and 20 g/L of xylose were produced from 100 g/L of the autohydrolyzed bagasse by the enzymatic saccharification using mixed cellulases, acucelase and meicelase. The maximum ethanol concentration, 20 g/L, was obtained from the enzymatic hydrolyzate of 100 g/L of the autohydrolyzed bagasse by the ethanol fermentation using Pichia stipitis CBS 5773; the ethanol yield from sugars was 0.33 g/g sugars.