• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.217-220
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• 2010

This paper presents an achieving method of reducing maximum acceleration for the missile by decrease of burst pressure in a nozzle closure. The relation of notch shape and burst pressure for a nozzle closure is examined by experiment. In the point of maximum acceleration reduction for a missile, an improved nozzle closure effects well compared with that of a reference closure by ground burning test of a gas generator.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.4
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• pp.443-448
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• 2010

In this paper, the changes in performance parameters, e.g., the combustor pressure, turbine power, engine mixture ratio, temperature of gas generator, and product gas, of a liquid rocket engine employing gas generator cycle with the variations in propellant-supply pressure have been described. Engine performance is numerically calculated using the 13 major system-level variables of the rocket engine. The combustor pressure and turbine power increase with an increase in the oxidizer-supply pressure and decrease with an increase in fuel-supply pressure. The lower mixture ratio of gas generator for increased fuel mass flow rate decreases the gas generator gas temperature and deteriorates the gas material properties as the turbine working fluid. The turbine power decreases with an increase in fuel-supply pressure; this results in a decrease in the main-combustor pressure, which is directly proportional to engine thrust.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.6
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• pp.45-52
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• 2010

This paper presents a mathematical-physical model to predict the performance of a gas pusher used as a separation system powered by a gas generator. A quasi-steady model is used in order to aid ballistic analysis for a propellant actuated device(PAD). The empirical coefficients of heat loss and friction were determined from experiments. The analytical approach of combustion, flow and movement of a piston inside the chamber of the PAD, consisted of a gas generator and a gas pusher, was simulated by numerical method based on the grain configuration design of the gas generator. The prediction method developed can be usefully applied to the design of separation mechanism systems.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.125-128
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• 2010

A pyrotechnic igniter with a relatively simple configuration was developed to secure the stable and reliable ignition of the gas generator in space launch vehicles. It was designed not only to provide a sufficient heat flux for the propellant ignition but also to ensure a structural safety under the conditions of very high temperatures and pressures. The burning tests of the igniters have been performed to decide several design parameters, and consequently the performance tests have proved that the pyrotechnic igniter developed in this study meets the design requirements.

• Aerospace Engineering and Technology
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• v.6 no.1
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• pp.128-135
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• 2007

Combustion characteristics of full-scale gas generators were studied experimentally by changing the injector number installed at the injector head. Three full-scale gas generators were utilized; they have same total mass flow rate but mass flow rates per injector are different. Thirteen, nineteen and thirty seven injectors, which have internal-mixing and double-swirl characteristics, are distributed in injector heads, respectively. The results showed that pressure fluctuations in the gas generators with 13 and 19 injectors didn't occur around longitudinal resonant frequency, however longitudinal-mode pressure fluctuation appeared slightly in the gas generator with 37 injectors. As the number of injectors increased, deviations of temperature distribution in the combustion chamber decreased gradually, but the damage of injector LOx posts became a little severe.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.309-315
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• 2006

Effects of injector or design on combustion characteristics of full-scale gas generators were studied. Three full-scale gas generators, which have same total mass flow rate but mass flow rate per injector is different depending on their designs, were manufactured. Thirteen, nineteen and thirty seven injectors, which have internal-mixing and double-swirl characteristics, are distributed in injector heads, respectively. The results showed that special pressure fluctuations in the gas generators with 13 and 19 injectors didn't appear around longitudinal resonant frequency, but small longitudinal-mode instability appeared in the gas generator with 37 injectors. As the number of injectors installed in injector heads increased, temperature distribution in combustion chambers showed small deviations, but the damage of LOx posts increased.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.366-370
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• 2008

Mode analysis is very important for the development of liquid rocket engine in various applications. We developed a mode analysis program for the gas-generator cycle liquid rocket engine by proposing 13 independent equations with 13 independent variables which can be solved by Newton method. As an example we calculated the change of engine operating mode according to the control valve's loss coefficient change located in the gas-generator oxidizer supply line. And we concluded that this program can give basic idea for the mode analysis of gas-generator cycle liquid rocket engine.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.107-110
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• 2008

The test range for turbopump and gas generator coupled test was determined considering the engine system test area which cover the qualification and development. Based on the test range, we determined the required loss coefficient for the throttle valves and lines.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.110-113
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• 2007

LES code was developed and verified to investigate the turbulence evolution in the gas generator equipped with turbulence ring. We compared mixing enhancement of various turbulence rings having different shape and size. To qualify the mixedness, we used two perturbation values of energy and enstrophy.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.196-200
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• 2006

This paper describes the current development status of the major subsystems, turbopump and gas generator, for a turbopump-fed liquid oxygen-kerosene rocket engine system. As a secondary stage of the liquid rocket engine development test, turbopump-gas generator powerpack tests are planned. The schematics of the test hardware and the test facility for the TP+GG coupled test are presented. The results of a preliminary analysis for operating regimes of the TP+GG coupled test are also presented.