• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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• pp.89-91
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• 2012

The numerical simulation for detonation failure of ammonium nitrate (AN) based non-ideal explosives is carried out with an accurate and state-of-the-art Eulerian method. Detonation failure is readily observed in the rate stick experiments utilizing the AN mixture explosives and the inert confinements of varying thicknesses. The composition of non-ideal explosives and thickness of the confinements influence the characteristics of detonation failure. Calculated results are compared against the experimental data of both unconfined and confined rate stick problems and provide a reliable guideline to establish a fine-tuned chemical kinetic model for detonation failure.

• Advances in aircraft and spacecraft science
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• 제5권5호
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• pp.533-550
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• 2018

Detonation transmission between propane/oxygen (donor) and propane/air (acceptor) with an abrupt area change is experimentally studied. In the donor, there are two types of incident detonation waves: A self-sustained Chapman-Jouguet (CJ) detonation wave and an overdriven detonation wave that is a result of the difference in the initial donor pressure ratios. The piston work is used to characterize the strength of the incident detonation wave. For an incident CJ detonation wave, the re-initiation of a detonation wave in the acceptor depends on the initial pressure in the donor and the expansion ratio. The axisymmetric and non-axisymmetric soot patterns respectively correspond to direct detonation and detonation re-initiation. For an incident overdriven detonation wave, the re-initiation of a detonation wave in the acceptor strongly depends on the degree of overdrive.

• 한국터널지하공간학회 논문집
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• 제10권2호
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• pp.185-191
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• 2008

본 연구에서는 정밀한 초시설정이 가능한 전자뇌관을 이용하여 터널에서의 다단 시차 분할발파(OBM)를 실시하며 대형 대단면 지하 공간 창출 요구에 발맞추어 기존뇌관(비전기뇌관)과의 비교를 통해 진동 소음 저감효과와 시공성, 효율성을 비교 검토하자 하였다. 본 연구를 통해 전자뇌관 적용 시 진동 소음 제어 및 비산거리, 여굴량, 파쇄입도가 비전기뇌관가 비교하여 양호한 결과를 나타냄을 확인할 수 있었다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2005년도 제31회 KOSCO SYMPOSIUM 논문집
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• pp.28-31
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• 2005

The numerical simulation is conducted for analysis flame structure of superdetonative ram accelerator experiment by ISL(French-German Research Institute in Saint Louis). Fully coupled chemically non-equilibrium Navier-Stokes equation is used. Shockwave structure of superdetonative ram accelerator and behavior of detonation wave is studied. Maintaining of detonation wave is very important to accelerate projectile, Because detonation wave make high pressure gases and this high pressure accelerate projectile.

• 화약ㆍ발파
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• 제40권3호
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• pp.33-43
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• 2022

화약류 저장소는 내부 폭발 시 구조물에 가해지는 영향을 최소화하기 위해 내벽과 일정 거리 이격하여 화약류를 저장하고, 예기치 못한 폭발에 나머지 폭약의 순폭을 방지해야 한다. 따라서 안전한 화약류 저장을 위해 저장소 내부에 폭약의 분할 배치를 모사하여 순폭 실험을 진행하였다. 본 연구에서는 에멀젼 폭약 사이의 이격거리, 배치를 달리 적용하여 직경의 2배(2D)에서 순폭되고, 2.5배(2.5D)에서 불폭됨을 확인하였다. 순폭도와 화약류 저장소 크기를 감안하여 폭약량 3kg을 설정하였고 다양한 배치 변화에 따른 순폭실험 결과 대부분 불폭되어 해당 배치 적용 시 안전성을 확인하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.45-52
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• 2008

In order to investigate the initiation and propagation processes of a spherical detonation wave induced by direct initiation, numerical simulations were carried out using two-dimensional compressible Euler equations with an axisymmetric assumption and a one-step reaction model based on Arrhenius kinetics with various levels of ignition energy. By varying the amount of ignition energy, three typical initiation behaviors, which were subcritical, supercritical and critical regimes, were observed. Then, the ignition energy of more than $137.5{\times}10^6$ in non-dimensional value was required for initiating a spherical detonation wave, and the minimum ignition energy(i.e., critical energy) was less than that of the one-dimensional simulation reported by a previous numerical work. When the ignition energy was less than the critical energy, the blast wave generated from an ignition source continued to attenuate due to the separation of the blast wave and a reaction front. Therefore, detonation was not initiated in the subcrtical regime. When the ignition energy was more than the minimum initiation energy, the blast wave developed into a multiheaded detonation wave propagating spherically at CJ velocity, and then a cellular pattern radiated regularly out from the ignition center in the supercritical regime. The influence on ignition energy was observed in the cell width near the ignition center, but the cell width on the fully developed detonation remained constant during the expanding of detonation wave due to the consecutive formation of new triple points, regardless of ignition energy. When the ignition energy was equal to the critical energy, the decoupling of the blast wave and a reaction front appeared, as occurred in the subcrtical regime. After that, the detonation bubble induced by the local explosion behind the blast wave expanded and developed into the multiheaded detonation wave in the critical regime. Although few triple points were observed in the vicinity of the ignition core, the regularly located cellular pattern was generated after the onset of the multiheaded detonation. Then, the average cell width on the fully developed detonation was almost to that in the supercritical regime. These numerical results qualitatively agreed with previous experimental works regarding the initiation and propagation processes.

• 한국연소학회:학술대회논문집
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• 한국연소학회 제26회 KOSCO SYMPOSIUM 논문집
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• pp.57-62
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• 2003

A general procedure of obtaining reliable one-step kinetics model for hydrocarbon mixture from the fully detailed chemistry is described iin this study. One-step theoretical formulation of the induction parameter model IPM uses a theoretical reconstruction of the induction time database obtained from a detailed kinetics library. Non-dimensional induction time calculations is compared with that of detailed kinetics. The IPM was latter implemented to fluid dynamics code and applied for the numerical simulation of detonation wave propagation. The numerical results including the numerical smoked-foil record show the all the details of the detonation wave propagation characteristics at the cost around 1/100 of the detailed kinetics calculation.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.671-686
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• 2004

The shock-induced combustion ramjet (shcramjet) is a hypersonic airbreathing propulsion concept which over-comes the drawbacks of the long, massive combustors present in the scramjet by using a standing oblique detonation wave (a coupled shock-combustion front) as a means of nearly instantaneous heat addition. A novel shcramjet combustor design that makes use of wedge-shaped flameholders to avoid detonation wave-wall interactions is proposed and analyzed with computational fluid dynamics (CFD) simulations in this study. The laminar, two-dimensional Navier-Stokes equations coupled with a non-equilibrium hydrogen-air combustion model based on chemical kinetics are used to represent the physical system. The equations are solved with the WARP (window-allocatable resolver for propulsion) CFD code (see: Parent, B. and Sislian, J. P., “The Use of Domain Decomposition in Accelerating the Convergence of Quasihyperbolic Systems”, J. of Comp. Physics, Vol. 179, No. 1,2002, pages 140-169). The solver was validated with experimental results found in the literature. A series of steady-state numerical simulations was conducted using WARP and it was deter-mined by means of thrust potential calculations that this combustor design is a viable one for shcramjet propulsion: assuming a shcramjet flight Mach number of twelve at an altitude of 36,000 m, the geometrical dimensions used for the combustor give rise to an operational range for combustor inlet Mach numbers between six and eight. Different shcramjet flight Mach numbers would require different combustor dimensions and hence a variable geometry system in or-der to be viable.

• 한국추진공학회지
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• 제20권5호
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• pp.19-30
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• 2016

파이로테크닉 착화기의 충격파 전달에 의한 폭굉 반응을 해석하기 위하여 고폭약의 폭압 발달 및 비반응 물질의 압력 감쇠 현상을 연동하여 모사할 수 있는 하이드로다이나믹 솔버를 구성하였다. 본 연구에서는 소량의 시약으로 기폭 판단이 가능한 SSGT의 시험 및 전산모사를 수행하여 97.5% RDX로 구성된 수폭약의 충격에 대한 점화 민감도를 정량화하였다. 파이로테크닉 착화기를 형상화 한 여폭약(HNS+HMX) - 격벽(STS) - 수폭약(RDX)으로 구성된 TBI 화약 트레인을 고려하여 충격파 전달을 해석함으로써 반응 및 비반응 물질 간 상호작용에 의한 임계 격벽 두께 및 기폭 압력 간의 관계를 규명하고, 소형 파이로 착화기의 작동특성을 검증하였다.

• 한국추진공학회지
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• 제21권5호
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• pp.10-18
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• 2017

알루미늄 입자들이 함유된 고폭약의 비정상 데토네이션 전파속도에 대하여 수치 해석을 수행하였다. 알루미늄 입자의 점화와 연소는 고폭약에 비해 상대적으로 긴 시간이 요구되기 때문에, 알루미늄 입자연소에 의한 에너지 발산은 고폭약의 데토네이션 후방에서 이루어진다. 이러한 비정상 데토네이션에 대한 수치해석은 기체상과 균일하게 분포된 고체 입자와의 질량, 운동량, 에너지 교환을 다루는 이종매질 이론을 이용한다. 알루미늄 입자가 함유된 고폭약의 데토네이션 전파에 대한 수치 해석은 폭약 HMX에 대하여 수행되었으며, 5~25%의 알루미늄 함량과 0.5, 7, $15{\mu}m$의 알루미늄 입자크기에 대한 수치 해석 결과와 실험 결과를 비교하여 검증하였다.