• 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.19 no.5
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• pp.37-45
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• 2015

Prediction of combustion instability within a solid-propellant rocket motor has been conducted with the classical acoustic analysis. The effect of particle size distribution on the instability has been analyzed by comparing the log-normal distribution to the fixed mono-sized particle followed by a survey of motor length scale effect between the baseline model and small scale model. Particle damping effect was more efficient for the small scale motor which has a relatively high unstable mode frequencies. It was also revealed that the prediction results by considering the particle size distribution show an overall attenuation of fluctuating pressure amplitude with respect to the mono-sized case.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.1
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• pp.77-83
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• 2021

In the current study, the numerical method was established to predict the performance of a solid rocket motor with two kinds of propellants. On the basis of a numerical study, an internal ballistics analysis code was developed. To verify the internal ballistics analysis code two solid rocket motors were manufactured and tested. The accuracy and applicability of the internal ballistics code for dual-propellant solid rocket motor were verified by comparing the experimental results with the numerical calculation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2002.04a
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• pp.72-72
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• 2002

건국대학교 연소추진 실험실에서 수행할 하이브리드 로켓 모터 연소특성 연구를 위한 실험장치를 설계하고 구성하였다. 실험장치를 제작하기 전에 기본적인 설계요구사항을 바탕으로 모터의 제작을 위한 수치코드를 작성하였다. 연소실 압력과 그레인의 형상, 산화제와 고체연료의 종류를 바탕으로 작성한 수치코드를 사용하여 로켓 모터를 설계하였다. 모터 설계코드를 통하여 세부적인 로켓모터와 노즐의 크기, 특성속도. 연소시간과 공급산화제의 유량 등을 계산하였고, 설계 전에 문헌연구와 이론을 바탕으로 일반적으로 실험실에서 사용되는 하이브리드 로켓 모터에 근접하게 설계를 진행하여 시행착오를 최소화하였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.6
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• pp.631-638
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• 2015

In this study, semiquantitative failure mode, effects, and criticality analysis (FMECA) for the reliability analysis of a solid rocket propulsion system is performed. The semiquantitative FMECA is composed of failure mode and effects analysis (FMEA) and criticality analysis (CA). To perform FMECA, the structure of the solid rocket propulsion system is divided into 43 parts down to the component level, and FMEA is conducted at the design stage considering 137 potential failure modes. CA is then conducted for each failure mode, during which the criticality number is estimated using the failure rate databases. The results demonstrate the relationship between potential failure modes, causes, and effects, and their risk priorities are evaluated qualitatively. Additionally, several failure modes with higher criticality and severity values are selected for high-priority improvement.

• The Journal of the Acoustical Society of Korea
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• v.39 no.4
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• pp.371-377
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• 2020

Combustion instability occurred in the combustion test of solid rocket motor with large aspect ration Length/Diameter (L/D) and cylinder-slot grain. As a result of spectral analysis of the pressure perturbation, it was confirmed that the central axis longitudinal frequency was dominant, so that the length of the cylinder part was increased to eliminate the coincidence with acoustic node. In addition, acoustic modal analysis and flow analysis were performed to analyze the cause of instability by unsteady flow structure in solid rocket motors. It was confirmed that the combustion instability is reduced by quantitative comparison of the amplitude and frequencies of the pressure inside the combustion chamber using the grain shape before and after the design change. Finally, a combustion test was performed to verify that the combustion instability was resolved as in the flow analysis.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2002.04a
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• pp.60-60
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• 2002

비행탄의 종말속도증대를 위하여 고체램제트를 이용하는 개념은 현재 세계적으로 여러나라에서 연구 중에 있다. Solid Fuel Ramjet Propulsion(고체연료 렘제트 추진)은 로켓추진에 비하여 월등히 높은 비추력을 가지며 구조적으로 매우 간단하여 탄의 사거리 및 평균속도를 증대시키는 좋은 수단으로 사용되고 있다. 그러나 간단한 구조에도 불구하고 고체렘제트의 작동은 매우 다양한 물리적 현상이 연관되므로 필요한 성능을 얻기 위해서는 이들의 상호 작용을 고려하여 설계의 최적화 및 성능 예측이 필요하다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2000.04a
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• pp.25-25
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• 2000

가스발생기와 같이 로켓모터에서 추력이 아닌 기체압 형태의 에너지를 일정한 시간동안 얻고자 하는 경우, 로켓모터의 크기 및 추진제 충전율을 고려하여 그레인 형태를 단면 연소형으로 선택할 수 있다. 단면 연소형 그레인을 가진 로켓모터는 그레인의 연소시, 일찍 연소된 부분의 라이너가 추진제 연소 화염에 노출되면서 표면부터 서서히 분해가 진행되며, 분해물질의 일부는 추진제에 포함된 산화제 성분에 의해 산화되어 기체화 될 수 있다. 산화제 성분이 충분치 않은 경우에는 고체 입자 형태로 추진제 연소 기체와 함께 배출되며, 이는 일차연기(primary smoke)의 일종으로 볼 수 있다. 가스 발생기에서 얻고자 하는 기체는 고체 입자가 포함되지 않은 깨끗한 기체형태인 경우가 대부분이며, 따라서, 무연 라이너 및 내열재의 연구가 필요하다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.79-82
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• 2005

The hybrid rocket has been known for over 50 years. It is safe and cheap but wasn't widely used for the deficit of low regression rate. However, the hybrid rocket propulsion system will replace a lot of fields of missiles, rockets and propulsion systems of launch vehicles with new development of paraffin based solid fuel composition

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.1
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• pp.30-38
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• 2002

Bullet impact tests for two solid rocket motors were performed and its results were compared and analyzed. One was loaded with the existing propellant with decreased weight content of burning rate catalyst and added high density additives to improve mechanical properties and the other was loaded with the existing propellant with decreased weight content of burning rate catalyst to improve its insensitivity as well as to maintain the ballistic performance. The composite cases were used for both motors.