• Clean Technology
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• v.29 no.1
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• pp.1-9
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• 2023

Waste explosives such as useless ammunition discharged from the military and coproduced useless explosives during the manufacturers production process have been continuously produced. These are difficult to dispose with normal waste treatment facilities due to the dangers of fire and explosion. An open burning or an open detonation at military designated disposal facilities is a classical treatment method for the dangerous explosives. The classical method raises various environmental problems by the emission of hazardous materials. An air pollution by the emission of hazardous gases such as SO_x and NO_x, soil and water contaminations by the accumulation of non-biodegradable heavy metals, are representative pollution examples. To overcome these problems, various processes for eco-friendly waste treatment methods have been developed, and some processes have already been operated in some countries. In the current report, various eco-friendly disposal processes for waste explosives or harmful materials, and their advantages and disadvantages are documented to suggest future development directions for reducing the hazardous substances by the treatment processes.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.72-75
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• 2007

레이저를 steel 표면에 조사하면, steel은 레이저의 복사 에너지를 홉수하여 급격히 가열되어 온도가 증가한다. 이때 steel에서는 phase explosion이 발생하고 shock wave와 플라즈마가 생성된다. 본 연구에서는 이 steel의 후면에 고폭화약을 접해 놓고 레이저 가열에 의한 화약의 점화 현상을 살펴보았다. 이를 위해 heat diffusion equation과 chemical heat release를 사용하였고, 고에너지 물질의 열분해 반응을 위해 3 step global kinetics를 사용하였다. 또한, 계산된 결과는 실험 결과와의 비교를 통해 검증 되었다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.482-488
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• 2017

Recently, weapon system has been highly regarding IM ability. Explosive is positively necessary in weapon system and it is principle component that must be improved for IM as the most hazardous material. RDX is one of energetic materials used the most at present since 1930s. It is being applied a lot to most of explosive in warhead and artillery and rocket propellants in these latter days due to its low cost and high energetic characteristics. However, it has a disadvantage which is more sensitive than some insensitive explosive like NTO, DADNE recently developed. To overcome this, researches have been continued about insensitive RDX and we are performing the study as well. In this study, we developed to apply reduced sensitivity RDX to pilot scale and mass production and we could confirm a result by shock sensitivity test.

• Analytical Science and Technology
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• v.28 no.6
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• pp.430-435
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• 2015

Two-dimensional analysis between the explosive performance and the impact sensitivity for methylnitroimidazole derivatives was performed to understand where these new energetic molecules could be utilized. The explosive performance was analyzed with the Cheetah program, while the impact sensitivity was predicted using neural network analysis. Successive nitration of methylimidazole made the molecule more sensitive, but methyltrinitroimidzole appeared to have a relatively good safety characteristic. We recently developed a novel method to analyze the potential usage of new energetic molecules using a two-dimensional chart, where the explosive performance and the impact sensitivity were located on the X-axis and Y-axis, respectively. An analysis of a two-dimensional plot between the performance and the sensitivity indicated that methyldinitroimidazole would be useful for insensitive explosive formulations, while methyltrinitroimidazole was forecasted for use as an ingredient for high explosive formulations.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.4
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• pp.32-42
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• 2013

We study the gap effect on detonating high explosives using numerical simulation. The characteristic acoustic impedance theory is applied to understand the reflection and transmission phenomena associated with gap test of high explosives and solid propellants. A block of charge with embedded multiple gaps is detonated at one end to understand the ensuing detonation propagation through pores and non uniformity of the tested material. A high-order multimaterial simulation provides a meaningful insight into how material interface dynamics affect the ignition response of energetic materials under a shock loading.

• Explosives and Blasting
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• v.41 no.3
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• pp.1-12
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• 2023

A basic assessment of techniques to mitigate the risk of blast shock waves from proximity explosions was conducted. Common existing techniques include using mitigant materials to form barriers around the explosive or in the direction of propagation of the shock wave. Various explosive energy dissipation mechanisms have been proposed, and research on blast shock wave mitigation utilizing impedance differences has drawn considerable interest. In this study, shear thickening fluid (STF) was applied as a blast mitigation material to evaluate the effectiveness of STF mitigation material on explosion shock wave mitigation through explosion experiments and numerical analysis. As a result, the effectiveness of the STF mitigant material in reducing the explosion shock pressure was verified.

• Explosives and Blasting
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• v.34 no.4
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• pp.10-18
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• 2016

Explosive blasting utilizes the energy produced from the explosion of explosive materials. Since the black powder, the first type of explosive, was invented, various types of explosives have been developed until a recent emulsion explosive which is powerful as well as safe in use. The detonators continue to be developed from safety fuse to the recent electronic detonators which allow extremely accurate and flexible control of delay time. However, the good explosives and detonators do not always lead to the good blast results. It entirely depends on the blast engineer. It is necessary to develop the empirical or theoretical models based on the field experience and sound theoretical algorithm. Such models would be very useful for blast design and, furthermore, provide the idea of further technical development. This paper introduces some models used in explosive blasting and attention to be paid for field application.

• Clean Technology
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• v.15 no.4
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• pp.233-238
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• 2009

Supercritical fluid processes have gained great attention as a new and environmentally-benign method of preparing the microparticles of energetic materials like explosives and propellants. In this work, RDX (cyclotrimethylenetrinitramine) was selected as a target explosive. The microparticle formation of RDX using supercritical anti-solvent (SAS) recrystallization process was performed and the effect of operating variables on the size and morphology of prepared particles was observed. N,N-Dimethylformamide was used as organic solvent for dissolving the RDX. The size of the RDX particles decreased remarkably up to less than $10\;{\mu}m$ by SAS recrystallization. In the range of operating conditions of the SAS process studied in this work, the finest RDX particles were obtained at 313.15K, 150 bar, and 15wt% RDX concentration in feed solution.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.342-349
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• 2012

We study the gap effect on detonating high explosives using the characteristic acoustic impedance theory and numerical simulation. A block of charge embedded with multiple gap inserts is detonated at one end to understand the ensuing flame propagation through multiple gap materials. The present high-order multimaterial simulation provides meaningful validation of complex interface tracking algorithm as it is implemented in the SNU-Hydropack code.

• Explosives and Blasting
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• v.33 no.2
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• pp.1-14
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• 2015

This study was performed to investigate the manufacturing process of the Yeomcho(potassium nitrate), a necessary raw material for making gunpowder using soils and ashes by our ancestor. 10 types of soils including underfloor soil and 6 kinds of ashes including mugwort ash were collected, referencing the historical record. The ionic components extracted from the soils and ashes were analyzed by ICP(inductively coupled plasma atomic emission spectrometer) and IC(ion chromatograph). Nitrate ions and potassium ions were dominantly contained in soils and ashes, respectively. In particular, nitrate ions were found in the highest lebels in underfloor soil which often has much exposure to human living environments and accumulated fine organic matter. Potassium ions contained in ash was affected significantly by the type of plant and the growth environments and the measured levels were the highest in mugwort ashes. Yeomcho of 68% purity was obtained from the soil and ash mixture of 1:1 and thid purity was improved by about 14% by fractional crystallization method.