• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.177-180
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• 2009

A Possibility of combustion instability on longitudinal mode has a high level at large scale of L/D. Solid propellant has a metal particle and a grain of control to pressure oscillation. Solid rocket motor in slotted-tube grain controls pressure oscillation of longitudinal mode. If slot length is shot, pressure oscillation of longitudinal mode is amplified by cylinder part after middle phase of total burn time. A study has analyzed pressure oscillation of longitudinal mode at spectrum and acoustic modal analysis at pressure of result on static firing test.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.1
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• pp.28-36
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• 2016

Theoretical model of a variable thrust solid rocket motor with a pintle nozzle was derived. For the chamber pressure control, classical model linearization and proportional-intergral controller was used. And then two types of gain scheduling controller were suggested to imporve controller performance for the non-linear propulsion model. Considering characteristics of systems, control gains were scheduled by chamber pressure or free volume. Step responses of each controllers were compared. As a result, the proper control algorithm about characteristics of variable thrust rocket motor was suggested.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.1
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• pp.55-62
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• 2011

In this study, we tried to improve the thrust control performance through the thrust control combustion experiment of the hybrid rocket. We constructed the system which controls the oxidizer flow by combining a needle valve with a stepping motor and controlling the stepping motor drive according to the thrust control command order. Gas oxygen was used as the oxidizer for two different propellants, PE(Polyethylene), PC(Polycarbonate), respectively. To improve the slow response time and the oscillation phenomenon in the beginning stage of the thrust control combustion experiment, we measured and analyzed the change of the flow speed of the propellant pipe. The revised thrust control combustion experiment showed that the thrust was stably controlled with the margin or error from the thrust command within ${\pm}1$ N.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.1
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• pp.31-35
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• 2010

This paper presents the development of automatic defect detection program using 3D computed tomography image of small solid rocker motor. We applied the neighbor pixel comparison algorithm with beam hardening correction for the recognition of defect. We made the artificial defect specimen in order to decide a standard CT value of defect. The program was tested with 150 small solid rocket motors and it could detect the disbond, crack, foreign material and void. The program showed more reliable and faster results than human inspector's interpretation.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.6
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• pp.85-91
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• 2012

This paper describes the results of study on reaction of insensitive igniter in which a pyrosensor is automatically sensing the rate of risk of fire or explosion of solid rocket motor exposed to an unexpected fire and makes the rocket motor burn itself safely. The Slow Cook Off(SCO) test following the regulation of MIL-STD-2105D was carried out with a rocket motor loaded with HTPB propellant, in which a thermal pyrosensor igniter was installed. The auto-ignition temperature measured was approximately $140^{\circ}C$ and it corresponded to Type V(Burning) reaction in SCO test, while the temperature by Kissinger equation was calculated to be $165.5^{\circ}C$.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.1
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• pp.93-99
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• 2015

The dual pulse rocket motor(DPRM) distributes the propellant energy effectively via pulse separation device(PSD) to improve the range and terminal velocity of the missile. There are two types of PSD such as bulk head type and thermal barrier type. A subscale thermal barrier type DPRM was designed, manufactured, and tested. The results showed good understanding of the characteristics of the PSD and will be applied to the design of the full scale DPRM.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.261-264
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• 2010

Dual Pulse Rocket Motor is a solid rocket motor with two grains separated by a bulkhead and rupture disc. The elasto-plastic explicit dynamic analysis of rupture disc was conducted by the finite element method. The effect of the slit geometry of rupture disc with radial slit was parametrically analyzed in terms of rupture time and shape. The results can be used to control the rupture pressure by changing the slit geometry of rupture disc.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.101-104
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• 2010

A bulkhead-type pulse separation device has been developed for the multi-pulse rocket motor. The design parameters of the pulse separation device were the shape of the rupture disc slit, welding conditions, and the implementation of the seal disc. The pneumatic tests of the fabricated pulse separation devices showed that the rupture pressure increased as the quantity of the rupture disc slit and welding strength increased and the seal disc was implemented.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.105-112
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• 2010

Dual Pulse Rocket Motor is a solid rocket motor with two grains separated by a bulkhead and rupture disc. The elasto-plastic explicit dynamic analysis of rupture disc was conducted by finite element method. The effect of the slit geometry of a rupture disc was analyzed for rupture time and shape by the parametric study. The results can be used to control the rupture pressure by the change the slit geometry of a rupture disc.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.781-786
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• 2017

This study aims to acquire a basic clustering technology of hybrid rocket motor for lunar lander, including the oxidizer flow distribution characteristic and the simultaneous ignition characteristic. The experimental setups were established to conduct a series of ground firing test of a clustered motor. The gaseous oxygen (GOX) and the HDPE (High Density PolyEthylene) were used as the oxidizer and the solid fuel, respectively. Experimental results which are the simultaneous pyrotechnic ignition characteristic, the oxidizer distribution characteristic and the pressure traces of each combustion chamber imply that the hybrid rocket clustered motor works successfully.