• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.10
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• pp.858-869
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• 2014

Most of the aerospace propulsion is based on the Brayton cycle, in which the combustion is held through the constant pressure process, but further improvement of performance by increasing compression ratio is challenged by mechanical limits. Detonation propulsions, regarded promising for high-speed propulsion for a lase decade, is more rigorously studied in these days as a game-changer for the improvement of thermodynamic efficiency of propulsion and power generation systems. Since, the additional compression by the strong shock of the detonation wave is considered increasing thermodynamics efficiency that is hardly achievable by the conventional compression systems. Present paper will give an introduction the latest technical trends on the Pulse Detonation Engines(PDEs) and the activities on the Pressure Gain Combustion (PGC) based on Constant Volume Combustion (CVC).

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.5
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• pp.60-69
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• 2016

This paper presents a numerical investigation on kerosene-air mixture detonation and behaviors of thermal elasto-plstic thin metal tube under detonation loading based on multi-material analysis. The detonation loading is modeled by the kerosene-air mixture detonation which is compared with Chapman-Jouguet (C-J) condition and experimental cell size. To conform the elasto-plastic model, plastic and elastic behaviors are verified by Taylor impact and plate bending motion, respectively. The numerical results are compared with the theory on burst pressure of tube. The critical deformable thickness with the thermal softening considered is good agreement with the theoretical value.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.2
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• pp.197-204
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• 2012

We explore the evolution of metal plasma generated by high laser irradiances and its effect on the surrounding air by using shadowgraph images after laser pulse termination and X-ray diffraction (XRD) of aluminum plasma ablated by a high-power laser pulse (>1000 mJ/pulse) and oxygen from air. Hence, the formation of laser-supported detonation and combustion processes has been investigated. The essence of this paper is in observing the initiation of chemical reaction between the ablated aluminum plasma and oxygen from air by the high-power laser pulse (>1000 mJ/pulse) and in conducting a quantitative comparison of the chemically reactive laser-initiated waves with the classical detonation of an exploding aluminum (dust) cloud in air. The findings in this work may lead to a new method of initiating detonation from a metal sample in its bulk form without any need to mix nanoparticles with oxygen for initiation.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.04a
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• pp.131-134
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• 2008

In this study, the lower detonation limits(LDL) and the upper detonation limits(UDL) of the flammable substances predicted with the appropriate use of the heat of combustion and the stoichiometric coefficient. The values calculated by the proposed equations were a good agreement with literature data within a few percent. From a given results, It is to be hoped that this methodology will contribute to the estimation of the detonation limits of for other flammable substances.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.278-281
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• 2012

Numerical studies were performed to investigate the three-dimensional front structure and dynamics features of detonation wave propagating in a circular tube such as Pulse Detonation Engine (PDE). By carrying out a series of parametric study using one step irreversible Arrhenius kinetics model, mechanisms of the three-dimensional front structure were investigated for two-, three-, four and six-cell mode detonations. A comparison with two-dimensional results, the effects of slapping transverse waves in radial direction were confirmed. In the all muti-cell modes, the detonation front structures and smoked-records on the wall are formed by the propagation of transverse waves along the wall in clockwise and counter-clockwise while the slapping move in radial direction. And the strength of reflected waves on the curved wall is changed by the multi-dimensional confinement effect.

• Explosives and Blasting
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• v.40 no.3
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• pp.33-43
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• 2022

In order to minimize the impact on the structure during an internal explosion, the explosives storage must be kept at a distance from the inner wall to prevent the sympathetic detonation of the others explosives in an unexpected explosion. For safe explosives storage, a gap test was conducted by simulating the split arrangement of explosives inside the storage. In this study, the separation distance and arrangement between the emulsion explosives were applied differently to be sympathetic detonation at 2D of diameter and non-detonated at 2.5D. Considering the coefficient of detonation transmission and the size of the explosives storage, the explosive amount of 3kg was set, and most of the gap tests according to various arrangement changes were non-detonated, and safety was confirmed when applying the batch.

• Journal of the Korean Chemical Society
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• v.30 no.4
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• pp.394-402
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• 1986

Detonation reaction in L.P.G./$O_2$ mixture gas has been investigated over the L.P.G. concentration range of 3∼45 volume%. The variation of detonation velocity with mixture ratio is very interesting as it shows and inflection point near at the stoichiometric ratio. This might be ascribed to the fact that the detonation reactions at fuel-rich condition and fuel-lean condition proceed via different mechanisms. The maximum detonation velocity of 2.65km/sec occurs not at stoichiometric ratio(${\phi}$=1) but at fuel-rich condition (${\phi}$=1.57). Assuming that a stable detonation wave must propagates with the constant velocity, The upper and lower limit of detonation were determined and found to be 40.0 and 3.40 L.P.G. volume% respectively. The shock-heating technique was also utilized for the measurement of self-ignition temperature onsetting a stable detonation wave at varous mixture ratios. The self-ignition temperature at stoichiometric ratio is $742{\pm}3{\circ}K$ and the self-ignition temperature increases as the mixture ratio deviates from the stoichiometric condition.

• 한국전산유체공학회:학술대회논문집
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• 2006.05a
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• pp.341-345
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• 2006

• Korean Chemical Engineering Research
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• v.52 no.6
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• pp.706-712
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• 2014

Explosives are reactive material that contain a great amount of high potential energy. They produce detonation if released suddenly, accompanied by the production of strong light, high heat, great noise and high pressure. Damage at surrounding detonation point is affected by high pressure and blast wave for explosives detonation. Consequently, analysis of pressure and blast wave is very important. This study focuses on the analysis of maximum overpressure and blast wave of explosives for safety assurance. First of all, four cases of the amount of HMX were selected. Secondly, maximum pressure and blast wave were calculated through detonation simulation along with a set of TNT and HMX quantities. The peripheral effect of detonation point was analyzed by calculating overpressure and absolute velocity and considering detonation occurred in the center of geometry by HMX. Also, maximum overpressure and blast wave of HMX were compared to equivalent amount of TNT, which was taken as a base case and verified through theoretical HMX graph. This study contributes to the base case for overpressure and blast wave of complex gunpowder containing HMX.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2007.03a
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• pp.351-357
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• 2007

We have compared a special character(pressure of explosion, gas volume, energy of explosion, temperature of explosion, strength) of different three emulsion explosives which is different velocity by Nitrodyn program that is calculated explosion reaction. We have analyzed the character of the vibration from a vibration data which is a result from test blasting in different velocity of detonation for three emulsion explosives of the same size(17mm) in the same rock. As a result, the vibration is decreased when the velocity of detonation is decreased within 40m from origin of explosion but it is familiar character over 40m, so there isn't much affect the velocity of detonation in decreased vibration over 40m.