• Journal of the korean Society of Automotive Engineers
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• v.6 no.4
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• pp.18-28
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• 1984

디이젤 엔진은 피스톤이 실린더 내를 왕복 운동하면서 압축행정에서 연료의 연소에 의해 발생된 고열을 받아 고온에서 작동되기 때문에 피스톤 헤드에서 받은 열은 속히 아래부분으로 전달시 키고 동시에 실린더 벽으로 전달되게 하여야 한다. 여기서 열이 문제가 되는 요소를 생각해 보면, (1) 고압 : 연소 최고폭발압력이 높기 때문에 압력상승률도 커져 격렬한 연소상태가 된다. (2) 고온 : 격심한 가스 유동과 실린더 직경이 크기 때문에 피스톤 헤드부의 온도가 높아진다. (3) 연소생성물 중에 엔진 및 윤활유에 악 영향을 주는 성분이 많다. (4) 경량, 저가격 구조 때문에 열적 및 역학적 변형이 일어나기 쉽다. (5) 사용조건이 가혹해 연료가 이상 현상을 가져온다. 위의 요소들을 가지고 온도의 분포, 열의 전달과정, 피스톤 냉각 등에 대해서 알아본다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.608-611
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• 2011

Laser-induced combustions and explosions generated by high laser irradiances were explored by Laser-Induced Breakdown Spectroscopy (LIBS) in rich, and stoichiometric conditions. The laser used for target ablation is a Q-switched Nd:YAG laser with 7 ns pulse duration at wavelength of 1064 nm laser energies from 40 mJ to 2500 mJ ($6.88{\times}10^{10}-6.53{\times}10^{11}\;W/cm^2$). The plasma light source from aluminum detected by the echelle grating spectrometer and coupled to the gated ICCD(a resolution (${\lambda}/{\Delta}{\lambda}$) of 5000). This spectroscopic study has been investigated for obtaining both the atomic signals of aluminum (fuel) - oxygen (oxidizer) and the calculated ambient condition (plasma temperature and electron density). The essence of the paper is observing specific electron density ratio which can support the processes of combustion and explosion between ablated aluminum plume and oxygen from air by inducing high power laser.

• Journal of the Korean Institute of Gas
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• v.16 no.4
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• pp.32-37
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• 2012

The aim of this study is to evaluate the characteristics of explosion and flame velocity that can be utilized to factories where Mg-Al alloy metal powders are handled in the form of raw materials, products or by-product for similar dust explosion prevention and mitigation. Because the strength of the blast pressure is the result due to flame propagation, flame velocity in dust explosion can be utilized as a valuable information for damage prediction. An experimental investigation was carried out on the influences of content ratio of Mg-Al alloy (mean particle size distribution of 151 to 161 ${\mu}m$). And a model of flame propagation velocity based on the time to peak pressure and flame arrival time in dust explosion pressure, assuming the constant burning velocity, leads to a representation of flame velocity during dust explosion. As the results, the maximum flame velocity of Mg-Al(60:40 wt%), Mg-Al(50:50 wt%) and Mg-Al(40:60 wt%) was estimated 15.5, 18 and 15.2 m/s respectively, and also tend to change with content ratio of Mg-Al.

• Journal of the Korean Institute of Gas
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• v.20 no.1
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• pp.29-39
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• 2016

Electrical apparatuses for use in the presence of explosive gas atmospheres have to be special 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 Maximum Experimental Safe Gap(MESG) 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 propane and acetylene by the test method and procedure of IEC 60079-20-1:2010.When the minimum MESG is measured, the concentration of propane, acetylene in the air is higher than the stoichiometric point and their explosion pressure is the highest value.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.10
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• pp.1081-1089
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• 2005

In order to examine the application feasibility of Orimulsion fuel in a commercial boiler using heavy fuel oil, a numerical and experimental research efforts have been made especially to figure out the fundamental combustion characteristics of this fuel in a small-scale boiler. One of the notable combustion features of Orimulsion fuel is the delayed appearance of flame location with the flame shape of rather broad distribution, which is found experimentally and confirmed by numerical calculation. This kind of flame characteristics is considered due to the high moisture content included inherently in the process of Orimulsion manufacture together with micro-explosion by the existence of fine water droplets. In order to investigate the effect on the combustion characteristics of Orimulsion, a series of parametric investigation have been made in terms of important design and operational variables such as injected amount of fuel, types of atomization fluid, and phonemenological radiation model employed in the calculation, etc. The delayed feature of peak flame can be alleviated by the adjustment of the flow rate of injected fuel and the generating features of CO, $SO_2$ and NO gases are also evaluated in the boiler. When the steam injection as atomizing fluid is used, the combustion process is stabilized with the reduced region of high flame temperature. In general, the calculation results are physically acceptable and consistent but some refinements of phenomenological models are necessary for the better resolution of pollutant formation. From the results of this small-scale Orimulsion boiler, it is believed that a number of useful information are obtained with the working computer program for the near future application of Orimulsion fuel to a conventional boiler.

• Fire Science and Engineering
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• v.13 no.2
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• pp.26-32
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• 1999

We had investigated combustion pro야$\pi$ies of rice bran dusts. Decomposition of rice bran d dusts with temperature were investigated using DSC and the weight loss according to t temperature using TGA in order to find the thermal hazard of rice bran dusts, and the p properties of dust explosion in variation of their dust with the same particle size. Using H Hartman's dust explosion apparatus which estimate dust explosion by electric ignition after m making dust disperse by compressed air, dust explosion experiments have been conducted by v varying concen$\sigma$ation and size of rice br뻐 dust. According to the results for thermodynamic stability of rice bran dust, there are little change of initiation temperature of heat generation 때d heating value for used particle size. But i initiation temperature of heat generation decreased with high heating rate whereas d decomposition heat increased with particle size. Also, the explosion pressure was increased as t the ignition energy increased and average maximum explosion pressure was 13.5 kgv'cnt for 5 BJ/60 mesh and 1.5 뼈Ie미 dust concentration.

• Journal of the Korean Institute of Gas
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• v.9 no.2 s.27
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• pp.1-7
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• 2005

The thermochemical parameters for safe handling, storage, transport, operation and process design of flammable substances are explosive limit, flash point, autoignition temperature, minimum oxygen concentration, heat of combustion etc.. Explosive limit and autoignition temperature are the major physical properties used to determine the fire and explosion hazards of the flammable substances. Explosive limit and autoignition temperature of methane fur LNG process safety were investigated. By using the literatures data, the lower and upper explosive limits of methane recommended 4.8 vol$\%$ and 16 vol$\%$, respectively. Also autoignition temperatures of methane with ignition sources recommended $540^{\circ}C$ at the electrically heated cruicible furnace (the whole surface heating) and recommended about $1000^{\circ}C$ in the local hot surface. The new equations for predicting the temperature dependence and the pressure dependence of the lower explosive limits for methane are proposed. The values calculated by the proposed equations were a good agreement with the literature data.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.340-343
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• 2011

Explosive bolts are reliable and efficient mechanical fastening devices having the special feature of a built-in release. The disadvantage of explosive bolt lies in that it is based on the high explosive effect of a pyrotechnic charge. The aim of the present work is to propose a pyrotechnically releasable mechanical linking device for two mechanical elements that does not suffer from such drawbacks. The pyro-lock using the pressure cartridge has the release characteristic without fragmentation and minimum pyro-shock. The present work is focused on the design, the interpretation of structure, the separation mechanism, separation force, and the results of various tests.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.274-278
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• 2011

We present an innovative method of multi-physics application involving energetic materials. We use an Eulerian methodology to address these problems. We have devised a new level set based tracking framework that can elegantly handle large gradients typically found in energetic response of high explosive and metals. Proper constitutive relations are employed to model the transient phases of gas, lliquid, and solid in the high strain rate regime. We use the confined and unconfined rate stick results to validate against the experimental data.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.10a
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• pp.205-207
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• 2015

LNG/LPG는 폭발가능성이 크기 때문에 매우 위험한 물질이다. LNG/LPG는 gas상태의 연료를 극 초저온에 고 압력 상태로 고농축한 액체 연료이다. 온도나 압력에 따라 물질의 상태가 변하기 때문에 폭발이나 화재가 일어날 수 있다. 하지만 무조건 사고가 일어나는 것은 아니며 현재까지도 화재나 폭발이 일어난 경우가 드물다. LNG/LPG선박은 충돌이나 파손 등 사고위기가 클수록 위험하다. 사고위기가 일어나는 요소로는 복잡한 항로, 많은 선박 수, 해마다 증가하는 LNG/LPG의 수요량 등이 있다. 본 연구에서는 LNG/LPG관련 해양사고 시나리오를 만들기 위해 사고 연계 고리(Accident chain)를 만들어 분석하였다. 해양사고의 연계 고리를 만들기 위해서는 story가 필요하다는 것을 알게 되었고, Risk를 통해 Peril과 Hazard를 분석 할 수 있었다. LNG/LPG의 위험성은 고압에 기인하는 위험, 화재위험, 동상위험, 화학반응의 위험, 질식 위험 등으로 분류 할 수 있었다. 아직까지는 LNG/LPG선박의 화재 및 폭발사고는 거의 일어나지 않았으나 매년 그 수요량이 증가하고 있고, 매우 위험한 물질임을 본 연구를 통해 알 수 있었다.