• 한국연소학회:학술대회논문집
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• 2012.11a
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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.

• Journal of Mechanical Science and Technology
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• v.15 no.12
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• pp.1822-1828
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• 2001

The experiment for the sympathetic detonation (Sudo et al., 1951) (Fukuyama et al., 1958) in water was conducted. Composition B (RDX: 64%, TNT: 36%, Detonation velocity: 7900m/s) was used for both donor (the thickness was 50mm, and the diameter was 31mm) and receptor charges. The distance between the donor and the receptor, and the thickness (5, 7.5, 10mm) of the receptor were varied in the experiments. In order to investigate the basic characteristics of the underwater sympathetic detonation of high explosive, the sympathetic detonation phenomena were visualized by a high-speed camera (HADLAND PHOTONICS, IMACON790) in forms of streak and framing photographs. The 200ns/mm streak velocity was 2㎲. Manganin gauges (KYOWA Electronic INSTRUMENTS CO. SKF-21725) were used for the pressure measurements. The gauges were set under the receptor. The pressures during the complete and incomplete explosions were measured.

• 한국연소학회:학술대회논문집
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• 2003.12a
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• pp.153-157
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• 2003

Supersonic and hypersonic aircrafts must pass wide range of speed to reach high speed region. But for existing engines the most efficient operating speed ranges are decided according to their flying speed, so an engine which mixes several engines like TRJ (Turbo Ramjet) and ARJ (Air Turbo Ramjet) has been planed. This mixed type engine has inefficiency that more than two engines must be installed simultaneously, but the pulse detonation engine (PDE) that uses detonation wave has a strong point that it can operate in all speed range with single engine. This paper deals with the simulation of the pulse detonation engine which uses hydrogen peroxide $(H_2O_2)$ mono propellant. Hydrogen peroxide is low-cost propellant, and it is reacted without oxidizer. Comparison between $H_2-O_2$ mixture with $H_2O_2$ mono propellant about thrust, pressure, temperature and velocity shows that $H_2O_2$ is a very useful propellant.

• Explosives and Blasting
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• v.42 no.1
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• pp.12-22
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• 2024

In this study, the vibration characteristics according to the detonation pattern between rows in the blasting site were investigated by analyzing the vibration waveform, vibration velocity, and dominant frequency. As a result, it was found that the vibration waveform was changed according to the detonation pattern between rows in the blasting zone, and both the vibration velocity and dominant frequency was showed different condition.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.8
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• pp.1989-1998
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• 1995

Characteristics of the flame propagation for normal and abnormal combustion in hydrogen premixture in a cylindrical constant-volume combustion chamber are studied numerically. A detailed hydrogen oxidation kinetic mechanism, mixture transport properties and a model describing spark ignition process are used. The calculated pressure-time history of the stable deflagration wave propagation agrees well with the experiment. The ignition of the premixture in the unburned gas, initiated by the hot spot, causes a transition from deflagration to detonation under some initial temperature and pressure. Under the initial conditions with high temperature and pressure, excessive ignition energy initiates a strong blast wave and a detonation wave that follows. The chemical reaction in the detonation wave is much more vigorous than that in the deflagration wave and the peak pressure in the detonation wave is much higher than the equilibrium value.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.1
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• pp.19-28
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• 2021

In rotating detonation engine(RDE), only the detonation wave is moving around the outer wall of the combustor. Neither a mechanical part nor flow is rotating in RDE. Thus, the RDE cross section is not necessary to be circular, but arbitrary closed section is possible. A RDE of tri-arc cross section is designed and As an example of an arbitrary cross sectioned RDE, a RDE of tri-arc cross section is designed in this study, and operational and performance characteristics were examined experimentally. The rotation of the detonation wave is confirmed by dynamic pressure sensor and high-speed camera, while the characteristics of the detonation wave were investigated at the concave and convex surfaces. In the present study, the thrust level of 17.0 N to 96.0 N was obtained depending on the mass flow rate.

• 한국연소학회:학술대회논문집
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• 2003.05a
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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.

• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.2
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• pp.82-91
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• 1999

Projectile shapes of the superdetonative ram accelerator have great effects on shock structures, detonation wave formation, and ram acceleration characteristics. In this study, cone-cylinder-cone, a baseline projectile configuration of the superdetonative combustion mode, double-cone configurations and power-law shape, have been numerically investigated to analyze the effect of the front/rear configuration changes, on the flow field around the projectile, detonation wave formation process, and projectile acceleration characteristics. Hence, a ram projectile configuration with conspicuously improved acceleration characteristics has been proposed by adjusting the double cone angle and height. The results provide useful information for the ram accelerator design optimization study.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.4
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• pp.383-391
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• 2009

The detonation wave characteristics of JP-7 and oxygen mixture is investigated by one-step induction parameter model (IPM) obtained from a detailed chemistry mechanism. A general procedure of obtaining reliable one-step kinetics IPM for hydrocarbon mixture from the fully detailed chemistry is described in this study. The IPM is obtained by the reconstruction of the induction time database obtained from a detailed kinetics library. The IPM was confirmed by the comparison of the induction time calculations with that from detailed kinetics. The IPM is later implemented to a fluid dynamics code and applied for the numerical simulation of detonation wave propagation. The numerical results show the detailed characteristics of the detonation wave propagation in JP-7 and oxygen mixture at affordable computing time, which is not be possible by the direct application of the detailed chemical kinetics mechanism of hydrocarbon fuel combustion.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.3
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• pp.81-89
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• 2018

In this study, the operating characteristics of a small-scale pulse detonation engine (PDE) were investigated experimentally for application as a small thruster and an igniter. The PDE was constructed using commercial gas tubes with an inner diameter of 4.22 mm. The operating and detonation propagation characteristics of the PDE were investigated over the ranges of equivalence ratios and operating frequencies. Measured detonation speed was close to 10% of the theoretical CJ values at 1 Hz and 5 Hz conditions. However, unstable propagation characteristics were shown at 20 Hz and lean conditions, where the velocity deficit was increased by 20~62%.