• 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 of Propulsion Engineers
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• v.21 no.4
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• pp.12-20
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• 2017

The ablation characteristics of graphite nozzle throat insert was analyzed for the use in solid rocket propulsion system. The propulsion system was composed of three types of conventional nozzles, such as De-Laval type, blast tube type, and submerged type. Various kinds of propellants were used in ten kinds of propulsion system that had different shapes with each other. Total forty eight tests were performed. From the results of the analysis, it was found that the ablation rate was increased for the higher average chamber pressure and the higher oxidizer mole fraction. A useful correlation for nozzle throat ablation rate was developed in terms of the chamber pressure, oxidizer mole fraction, and throat size. The calculated ablation rates from the correlation showed agreement within ${\pm}0.10mm/s$ with the experimentally determined values.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.162-166
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• 2005

A thermal resistance estimation of carbon/carbon composites used as the nozzle throat insert of solid rocket motor was performed using TPEM motor. Three types of TPEM motor and two types of propellant were employed. The ablation rate is higher for the higher chamber pressure and also higher for the higher concentration of oxidizing species in combustion gas, but it is lower for the higher material density.

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.1
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• pp.30-37
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• 2006

A thermal resistance estimation of carbon/carbon composites used as the nozzle throat insert of solid rocket motor was performed using TPEM motor. Three types of TPEM motor and two types of propellant were employed. The ablation rate is higher for the higher chamber pressure and also higher for the higher concentration of oxidizing species in combustion gas, but it is lower for the higher material density.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.11a
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• pp.165-168
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• 2000

로켓엔진에서 노즐은 추력을 발생하고, 단위 면적당 열 전달이 최대가 되는 곳으로 구조적으로 가장 취약한 부분이다. 이런 가혹한 조건에서 사용되어질 수 있는 4D 탄소/탄소 복합재를 제조하였으며. 초밀도화시, 탄화압력은 100bar 와 900bar 에서 각각 시행되었다. 만들어진 시편의 밀도는 1.5~l.9g/$cm^3$ 이었다. 실제 로켓을 모사할 수 있는 지상연소시험을 통해 밀도에 따른 삭마율을 계산한 결과, 밀도가 높을수록 삭마율은 감소하였다. 또한 3-point bending test를 통해 굽힘강도(flexural strength)를 측정하였으며, 굽힘강도를 개선시켜주었다.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.04a
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• pp.215-217
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• 2000

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.2
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• pp.200-205
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• 2010

Heat-resistance of W/$Y_2O_3$ as throat insert material was evaluated to develop rocket motor keeping thrust uniformly under condition of high-temperature, high-pressure and long-burn time. Test was conducted with varying burn time, and test results were compared with CIT. Test showed that ablation rate was decreased according as burn time was increased, and that ablation rate of W/$Y_2O_3$ was about 55 % of CIT. Macro/micro structures of throat insert did not show a peculiar phenomenon by increased burn time. In addition, the vacuum heat treatment is effective for the prevention of crack in throat insert.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.10a
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• pp.31-31
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• 1998

제트베인을 이용한 추력방향 제어장치를 개발하여 평균추력 2950 lbf, 평균 압력 714 psig, 연소시간 4.8초, 노즐 출구직경 약 100mm인 추진기관에 장착하고 이를 시험하고 분석하였다. 재질에 따른 제트베인의 삭마성을 알아보기 위하여 텅스텐과 구리(W/Cu), 지르코늄산화물과 텅스텐(ZrO$_2$/W), 지르코늄 산화물과 몰리브덴(ZrO$_2$/Mo)의 3가지 재질의 베인을 사용하였다 시험된 제트베인 재질 중 지르코늄 산화물과 몰리브덴(ZrO$_2$/Mo)의 합금을 사용한 베인이 내열성 및 삭마성에서 가장 우수하였으며(삭마량 27.65% 삭마율 5.7mm/sec), 지르코늄 산화물과 텅스텐(ZrO$_2$/W), 텅스텐과 구리(W/Cu)의 순서이었다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.10a
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• pp.30-30
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• 1998

Solid rocket motor case의 internal insulator로 미가류 형태의 내열재에 적당하게 tacky성과 삭막 특성을 고려한 조성을 개발하여 시스템에 성공적으로 적용하였다. 개발된 내열재의 주요 조성으로는 base polymer로 EPDM과 CR을 80/20으로 blend하여 적용했으며, 삭막 특성 향상을 위해 아라미드 섬유인 Kevlar 29를 5 phrs, Hydrated silica인 Zeosil 155를 30phrs 적용하였다. 이와 같은 조성으로 제작된 내열재는 삭마시험, 인장시험, 열특성시험 등 각종 특성시험을 수행하여 시스템에 적용하기 위한 성능을 확인하고 공정에 적용하였다. ST-8 표준 모타에 적용하여 삭막시험한 결과 삭마율 0.21mm/sec를 얻었고, 추진기관 사용 온도인 -4$0^{\circ}C$-6$0^{\circ}C$ 온도 범위에서 기계적성질 값을 측정하여 성능 저하가 없는 안정된 값을 얻었으며, DSC로 Tg point 측정 결과 -55$^{\circ}C$로 나타나 저온특성이 우수한 EPDM 내열재 특성을 확인할 수 있었다.

• Journal of the Korean Society of Propulsion Engineers
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• v.7 no.4
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• pp.39-45
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• 2003

Of the various means for active trajectory correction, a thrust vector control system represents the only principle independent of missile external forces so that this method is operative. The purpose of this study is to analyze the characteristic of jet vane TVC(Thrust vector control) system among mechanical jet deflection. To ensure high performance leading edge shape, aspect ratio and ablated condition is optimized. Supersonic flow system, jet vanes and nozzle with Mach number 2.88 and under expansion ratio 2 were designed to study aerodynamic characteristics of leading edge shape, aspect ratio and ablated conditions.