• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.253-257
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• 2011

Vortex generation mechanism by inhibitor in a solid rocket motor have been investigated by 3D Large Eddy Simulation turbulent model. Most of the result of the present study are in good agreement with experimental data and previous numerical calculation. Vortex generation and breakdown behind inhibitor are periodically observed between inhibitor and nozzle head by flow-acoustic coupling mechanism. Vortex generation frequency is the same as the second-mode frequency in the motor. The roll shape vortex generation behind inhibitor induces non-uniform flow field at the nozzle entrance and its throat.

• Journal of the Korean Society of Safety
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• v.13 no.4
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• pp.137-141
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• 1998

The combustion instability of a rocket motor can be predicted by the linear stability analysis. The most important input data in this analysis is the combustion response function of the solid propellant. In many cases, it is very difficult to measure the function. But, in that case, the combustion response function can be theoretically evaluated by properties of the propellant. In this study, the theoretical values were compared with measured values by T-burner. Data are relatively so well agreed that theoretical values are enough to be used in linear stability analysis of the rocket motor using a newly developed propellant.

• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.4
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• pp.114-122
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• 2000

Bullet impact tests for solid rocket motor were performed and its results wert described. Two motors were made of composite and steel for case material, respectively and their reactions to the bullet impact were compared. Throughout the tests it had been tried to setup the procedure of bullet impact test and criteria of the judgment for the reactions.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.460-463
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• 2011

Different kinds of solid rocket motors manufactured for various aim have their own shelf life. So they must be done away if not used. In general, ammonium perchlorate(AP) has used in the process of solid rocket motors, which is environmental pollutant. Out-burning and out-detonation were usual in the past, but they polluted the surrounding environment and raised safety issues. As an alternative to resolve these, water-washout process to separate the propellant from rocket motors and an eco-friendly way for recovering AP are studied in this paper.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.1
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• pp.9-15
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• 2012

An unsteady internal ballistic performance model was proposed to take account for the variance of local regression rate along the grain port of a hybrid rocket combustor. The characteristic parameters of hybrid rocket motor was investigated. The performance model of concern in the study was fairly comparable with the test result. The combustion coefficients and local burning characteristics of a hybrid rocket motor were evaluated. The local variation of the oxidizer mass flow rate results in the changes of local regression rate, pressure, temperature, and gas velocity to flow direction, which was analyzed quantitatively.

• Journal of Korean Society for Quality Management
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• v.51 no.4
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• pp.735-749
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• 2023

Purpose: The purpose of this study is to derive solutions and prevent similar cases from occurring by analyzing the causes of cracks found in temperature cycling tests of rocket motor. Methods: By combining the results of the current state confirmation test, non-destructive test, domestic and foreign rocket motor comparison test, cutting test, and adhesion test according to the number of times to apply mold release agent, a Cause and Effect Diagram analysis was performed to derive the cause of cracks. Results: Through this study, 26 factors that could cause cracking in rocket motors during temperature cycling tests were identified. Through various additional test results, a total of five causes were identified, including chemical and structural design of the joint between the propellant and stress relief insert, omission of procedure in the manufacturing procedures, natural aging due to temperature, and load accumulation due to temperature changes. The fundamental cause was confirmed to be insufficient consideration of the release properties of the propellant and stress relief insert. Conclusion: During the design process, it was confirmed that this could be solved by structurally or chemically designing the insert so that it does not combine with the propellant, or by applying a mold release agent during the manufacturing process.

• Aerospace Engineering and Technology
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• v.13 no.1
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• pp.129-141
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• 2014

Since 2006, an annual rocket competition for university students in America has been held by management of NASA to support the Space Launch System. This paper describes the significance and operational aspects of NASA Student Launch, a rocket competition for university students organized by NASA Marshall Center's Academic Affairs Office, to inspire students to pursue education and careers in science, technology, engineering, or mathematics (STEM) fields, which is Furthermore, It describes briefly activities of Korean national rocket competition for university students.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.475-478
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• 2005

Ducted rocket produces thrust by 2 steps, primary incomplete combustion in the gas generator, and secondary complete combustion reaction in combustion chamber mixed by air taken through duct. the range of a rocket is determined by the weight of propellant, especially the weight of fuel. So ducted rocket has more efficiency and high terminal speed compared to traditional solid rocket motor. This propulsion system expected to be applied to various kinds of missile for anti-aircraft, anti-ship

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.237-240
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• 2006

Hybrid propulsion systems provide many advantages in terms of stable operation and safety. However, classical hybrid rocket motors have lower fuel regression rate and combustion efficiency compared to solid propellant rocket motor. Accordingly, the recent research efforts are focused on the improvement of engine efficiency and regressionrate in the hybrid rocket engine. The present study has numerically investigated the combustion processes and the flame structure in the hybrid rocket engine. The turbulent combustion is represented by the flamelet model and Low Reynolds number $k-{\varepsilon}$turbulent model is employed to reduce the uncertainties for convective heat transfer near solid fuel surface having strong blowing effect. Numerical results suggest that the present approach is capable of realistically simulating the combustion characteristics of the hybrid rocket engines.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.245-248
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• 2006

Hybrid propulsion systems provide many advantages in terms of stable operation and safety. However, classical hybrid rocket motors have lower fuel regression rate and combustion efficiency compared to solid propellant rocket motor. Accordingly, the recent research efforts are focused on the improvement of engine efficiency and regression rate in the hybrid rocket engine. The present study has numerically investigated the combustion processes in the hybrid rocket engine. The turbulent combustion is represented by the flamelet model and Low Reynolds number $k-{\varepsilon}$ turbulent model is employed to reduce the uncertainties for convective heat transfer near solid fuel surface having strong blowing effect. Based on numerical results, the detailed discussions have been made for the effects of oxygen injection methods and oxygen injection flow rate on flame structure and regression rate in the vortex hybrid rocket engines