• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.88-91
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• 2005

The combustion characteristics of high burning HTPB/AP solid propellants have been investigated by means of a closed bomb method of interval volume of 200 co and 700 cc at pressures from 1000 to 30,000 psi. The burning rate data measured by closed bomb are in good agreement with strand burner test results at pressure from 1000 to 5000 psi using disc sample of 1 mm thickness. The burning rate dat by using 200 cc closed bomb are in general agreement with that of 700 cc closed bomb. At pressure between $5,000\sim7,000$ psi, a market increase in pressure dependence of the linear burning rate occurs for HTPB/AP propellant.

• Journal of Aerospace System Engineering
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• v.11 no.5
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• pp.42-49
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• 2017

The solid rocket motor(SRM) consists of a motor case, igniter, propellants, nozzle, insulation, controller, and driving device. The liquid rocket propulsion systems(LRPSs) cools the nozzle by the fuel and oxidizer but SRM does not cool the nozzle. The nozzle of SRM is high temperature condition and high velocity condition so occurs the erosion by combustion gas. This erosion occurs the change of nozzle throat and reduces thrust performance of rocket. The material of Rocket nozzle is minimization of erosion and insulation effect and endure the shear force, high temperature and high pressure. The purpose of this study is to investigate the erosion characteristics of solid rocket nozzles by each combustion time. Through the structure inspection of Graphite and C-C composite, identify the characteristics of the microstructure before and after erosion.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.5
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• pp.62-69
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• 2014

Infrared signature of rocket plume plays an important role for detection, recognition, tracking and minimzing for low observability. Infrared signatures of rocket plume with reduced smoke propellant and smokeless propellant are measured. In order to estimate the infrared signature of rocket plume, CFD analysis for flow structure of plume is performed, and layered integration method for estimating of infrared signature is used. Numerical and experimental results were in good agreement. Both propellants had similar infrared signature. Strong peak at $4.3{\mu}m$ region in the experimental results is appeared due to experimental error arising from the calibration procedure.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.1
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• pp.8-15
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• 2014

The ablation characteristics of graphite nozzle throat insert is analyzed for the use in solid rocket propulsion system. The propulsion system is composed of three types of conventional nozzles, such as De-Laval type, blast tube type, and submerged type. Various kinds of propellants are used in the thirteen kinds of propulsion system that has different shapes of each other. Total thirty seven tests are performed. From the results of the analysis, it is found that the ablation rate is higher for the higher average chamber pressure and the higher concentration of oxidizing species in combustion gas.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.1
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• pp.82-88
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• 2009

The structure of steady wave system is considered which is admitted by the continuum equations for materials that undergo phase transformations with exothermic chemical reaction. With its theoretical basis in one-dimensional continuum shock structure analysis, the present approach estimates the micro-width of waves associated with phase transformation phenomena, n-heptane is selected as the hydrocarbon fuel for evaporation and condensation analysis while HMX is used for melting and freezing analysis of solid rocket propellant. The estimated thickness of evaporation - condensation front of n-heptane is on the order of $10^{-2}$ micron while the HMX melting - freezing front thickness is estimated at 1 micron.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.307-310
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• 2005

This Study was performed for the Insensitive Munition Technology Program contract between Roxel and ADD. Two Slow Coo-off(SCO) tests and One fast Cook-off(FCO) test have been made based on MIL-STD-2105C. SCO and FCO tests were made in order to evaluate the behaviour of the hybrid rocker motor with insensitive igniter and two types of propellants of which burning rates were 9.8 mm/s and 21.2 mm/s @ 7 MPa each other. The Reaction level of the two rocker motors to SCO test was classified as type IV and that of FCO test was classified as type V.

• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.3
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• pp.77-87
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• 2006

Micro- or nano-size particles are required to improve the combustion efficiency and stability in the case of solid explosives and propellants. The micro-structural properties of an energetic material strongly influence the combustion and explosion behavior. However, the traditional size reduction techniques, including milling, are not suitable for production of ultra-fine size particles. As an alternative to the traditional techniques, various re-crystallization processes based on supercritical fluids have recently been proposed. Supercritical fluids are fluids at temperatures and pressures above their critical point. In principle, they do not give problems of solvent contamination as they are completely released from the solute when the decompression occurs. Rapid Expansion Supercritical Solutions(RESS) and Supercritical Anti-Solvent Process(GAS/SAS) are representatives of a nano-size particle formation process of energetic materials using supercritical fluids. In this work, various fine particle formation processes using supercritical fluids are discussed and the results are presented.

• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.1
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• pp.48-54
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• 1999

A method was disclosed for making phase stabilized ammonium nitrate(PSAN), where the process involves precipitation of ammonium nitrate(AN) with potassium dinitramide(KDN) from the aqueous solutions of their salts using a salting out technique. The organic solvent used as a precipitant was acetonitrile. The DSC results showed that the precipitates are PSAN, and AN is stable over the temperature range from $0^{\cire}C$ to $80^{\cire}C$ if the KDN concentration in the precipitated solids is greater than about 6 wt.%. The particles prepared are expected to be useful as an oxidizer for the solid rocket propellants and explosives.

• Journal of Mechanical Science and Technology
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• v.15 no.8
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• pp.1181-1187
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• 2001

The radiation driven response function (R$\_$q/) for AP and HMX propellant was obtained and compared with experimental results by using a simple $\alpha$$\beta$γ flame model rather than with detailed chemistry. For an AP propellant, the profile of heat release was assumed by the experimental data. The calculated R$\_$q/ shows a frequency shift of the peak amplitude to the higher frequency and a decrease in the maximum amplitude as radiation increases. In addition, it was found the increase in the total flux could enhance the mean burning rate γ$\_$b/ while the phase differences between the radiation and resulting conduction could consequently reduce the fluctuating amplitude Δγ$\_$b/. Fortunately, this is the qualitative duplication of the behavior recently observed in the experiments of RDX propellants. For HMX, the response function R$\_$q/ has been calculated and showed a quite good agreement with the experimental data. Even though the fairly good agreement of R$\_$q/ with experimental ones, the unsteady behavior of HMX was not reproduced as the radiation input increased. This is due to lack of the material properties of HMX or the physical understanding of HMX burning at high pressure.

• Journal of the Korea Institute of Military Science and Technology
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• v.12 no.5
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• pp.660-666
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• 2009

Thermoplastic polyurethane elastomer(PU-TPE) and energetic thermoplastic polyurethane Elastomer(E-PU-TPE) were prepared from Hexamethylene diisocyanate(HDI), 1,4-BD/AA ester polyol and glycidyl azide polymer(GAP-2400) as an energetic material by the addition polymerization. The PU-TPE and E-PU-TPE were characterized by FT-IR and GPC. Viscometer, DSC and UTM were used to investigate the viscose behavior with a various solvent, thermal properties and mechanical properties of PU-TPE and E-PU-TPE, which are of potential interest for the development of high performance binder of energetic solid propellants. It was found that $M_w$ of PU-TPE and E-PU-TPEs are over 100,000 and decreased with increase of GAP-2400 contents. $T_m$ and ${\Delta}H$ as thermal properties decreased and also tensile strength and elongation at break as mechanical properties decreased with increase of GAP-2400 contents.