• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.1
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• pp.9-14
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• 2019

Hydroxy-terminated polybutadiene (HTPB) propellants of solid rocket motors age differently under different storage temperatures. The shelf life of a solid rocket motor depends on the aging ratio of the HTPB propellant; it can be estimated through the viscoelastic properties by an aging test. This study analyzed the initial and natural aging properties during long-term storage. The initial properties were obtained from characterization and accelerated test results. The test results were obtained by analyzing the strain on cylindrical grains when a thermal load was applied.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.239-242
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• 2008

Combustion Characteristic with initial port-diameter of fuel was studied in hybrid propulsion system using cylindrical single port-grain. In order to understand a variation of combustion characteristic with initial port-diameter, experimental studies were performed with the GOX and $GN_2O$ as oxidizer, and PE as fuel. As results, burning rate decreased with increase of initial port-diameter of fuel. And the variation of burning rate with using $GN_2O$ is smaller than using GOX.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.6
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• pp.45-52
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• 2020

In this paper, a subminiature solid rocket motor(SSRM) was designed to develop a miniature smart-bullet and the designed propellant grain was made of thermoplastic propellant for production convenience of inner shape. The internal ballistics analysis and ground test were performed to investigate the performance of SSRM. And a numerical simulation was carried out to obtain basic data on the design of safety distance between the nozzle outlet and a gunner, the temperature distribution of exhaust gas was analyzed by comparing a numerical simulation and the results of IR camera.

• 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.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.9
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• pp.130-135
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• 2004

This paper describes the development of the dual-thrust rocket motor, which gets a significant change in thrust level by varying the burning area of the propellant grain. Reduced smoke propellant of low burning rate was formulated and the finocyl type grain was designed to get the boosting- and sustaining-phase of the thrust level. And the motor firing data were analyzed in detail. Developed motor was applied to the missile system to implement the successful flight test and this development helped to upgrade the performance of the missile system. The results will be usefully applied to the development of the similar rocket motors.

• 한국항공운항학회:학술대회논문집
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• 2016.05a
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• pp.14-18
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• 2016

본 연구에서는 하이브리드로켓 모터와 고체로켓 모터를 이용하여 목표 고도 1km인 2단 로켓 설계를 수행하였다. 비행 시나리오는 총 비행시간 51.59초, 1단부 로켓 연소시간은 3초이며 연소 종료 후 3초 뒤 단 분리를 수행하여 2단부 로켓 점화가 이루어져 총 3초간 연소가 진행된다. 1단부 모터는 하이브리드로켓으로써 5port의 HDPE를 연료 그레인으로 사용하였고 $LN_2O$를 산화제로 사용하였다. 2단부 모터는 고체로켓으로 KNSB(Sorbitol/$KNO_3$)추진제를 사용하였다. 단 분리는 영전자석을 이용하여 분리하며 2단부 모터의 점화는 광학 센서와 니크롬선 점화방식을 이용하여 점화하도록 설계하였다. 비행하는 동안 AVR를 이용해 압력, 가속도, GPS 등의 자료를 수집할 수 있도록 설계하였다.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.3
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• pp.61-67
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• 2017

In this study, Burning Area Analysis Program (BAAP) was developed by using VOF method to estimate the burning area of 3D shaped grain. The parametric study of mesh size, burning rate and time interval for numerical calculation was conducted. The result of BAAP is compared with the one from commercial 3D modeling software. Also the internal ballistic analysis was performed using the result of BAAP. In order to estimate the burning area and internal pressure with time, Chemical Equilibrium Analysis (CEA) was conducted with a composition of reduced smoke propellant. As a result, the web-averaged pressure was 5.34 MPa which is similar to the published research result.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.247-250
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• 2008

An experimental investigation was conducted to clarify the combustion characteristics and merge characteristics of PMMA-GOX and PE-GOX hybrid motor using multi-port fuel grain configuration. The regression rate of multi-port fuel grain is higher than the regression rate of single-port fuel grain by thermal conduction and chamber pressure. The merge of multi-port has an effect on hybrid rocket performance by change of a combustion area.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.2
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• pp.79-85
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• 2007

An internal ballistic model to predict the performance of a Polyethylene-GOX (PE-GOX) hybrid motor was proposed and evaluated. A theoretical treatment of the model was followed by detail discussion of each of the factors affecting the overall performance. The present model consists of the governing equations by considering the unsteady burn-back rate of the fuel grain and on-off response characteristics of a oxygen-supply valve. The numerical results using the 4th order Runge-Kutta scheme with temporal physicochemical properties showed good agreements with test results and the global effects of the performance parameters, such as the burning area of the fuel grain, O/F ratio, and etc., on the performance of the motor were analyzed.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.3
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• pp.70-77
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• 2014

In this paper, the development of unique model of the 2.75 inch rocket propulsion system is described. Recently developed korean 2.75 inch rocket propulsion system shows the improvement of a flame stability resulted from a change in the configuration of propellant grain, and of an incidental ignition protection function using the EMI(electromagnetic interference) filter on ignition system. Moreover it is shown that a directional flight stability is improved by increasing the number of fins and changing the nozzle configuration. Static firing test and thermal shock test were conducted for the validation before flight, and flight test of 210 rounds of rockets was conducted to verify the trajectory uniformity. In addition, intellectual property issues can be overcome with the unique korean 2.75 inch rocket motor as well as the performance improvement.