• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.71-74
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• 2010

Using the technology demonstration model of 75-tonf-class combustor which is expected to be used to the rocket engine of a korean space launch vehicle, 2 times of firing tests were carried out. Firing tests were done at 50% of the nominal flow rate because of incapability of the test facility and limit of the test bed strength. Through the low pressure firing tests of 75-tonf-class channel cooling thrust chamber, reliability and stability at the ignition and combustion phases were confirmed. Additionally it was foreseen that the 75-tonf-class thrust chamber would satisfy the performance requirements.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.4
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• pp.71-80
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• 2010

The KSLV-II(Korea Space Launch Vehicle-II) which being a successor of the KSLV-I is a space launch vehicle capable of delivering 1.5 ton-class satellite into a low earth orbit. The development of a 75 tonf-class liquid rocket engine(LRE) is planned on the basis of the technologies mastered through the preceded research of a 30 tonf-class LRE. The thrust chamber of the LRE is required to have higher combustion stability, structural integrity and thermal durability. This paper deals with the design requirements of the 75-tonf thrust chamber and a variety of technical considerations which have been conducted analytically in the course of the design for the realization of the requirements.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.265-268
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• 2005

A series of ignition tests had been conducted for a thrust chamber propelled by Jet A-1 and liquid oxygen with a chamber pressure of 52.5 bara and a thrust of 30 tonf. The chamber ignited by a hypergolic fluid, TEAL, keeps its first constant pressure low at $63\%$ of the design value by $61\%$ of a liquid oxygen mass flow rate and $67\%$ of fuel for 0.25 sec. The operating O/F ratio of the chamber was kept at lower values than that of the design operating condition throughout the whole ignition procedure. Surge of the chamber pressure is below $6\%$ of the design value.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.5-9
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• 2010

In the paper, the dynamic characteristics obtained from hot-firing tests of 1/2.5-scale thrust chamber for 75 tonf-class liquid rocket engine were described. To investigate the dynamic characteristics by engine start transient period and chamber pressure variation, hot-firing tests were performed in the chamber pressures of 30 bar and 60 bar. According to these variations, combustion stability in the combustion chamber was examined.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.12
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• pp.109-116
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• 2005

Elastic-plastic structural analysis for regenerative cooling chamber of liquid rocket thrust chamber is performed. Uniaxial tension test is also conducted for the copper alloy in order to get material data necessary for the structure analysis. The results of uniaxial tension test reveal that copper alloy become ductile after brazing process and flow stress becomes lower as temperature becomes higher. As a result of structural analysis using the material data, the deformation of cooling channel is more increased by thermal load than by internal pressure of cooling fluid. Therefore, the results of analysis show that structural stability and cooling performance of combustion thrust chamber which is designed to endure mechanical load and minimized a channel thickness are improved by decreased thermal load as possible.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.6
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• pp.26-37
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• 2011

A 75-tonf-class LRE(liquid rocket engine) thrust chamber with ablative material for technology demonstration was manufactured on the basis of development technologies of 30-tonf-class LRE. Hydraulic characteristics of the thrust chamber were examined through cold flow test and ignition test of low flow condition. Test result showed that hydraulic function was good. Side ignition method with igniter ring also showed a fine function of ignition in operating ways of static condition. But a close review is required to understand the phenomena of generation and extinction of specific frequencies showed in dynamic characteristics ways. To achieve these, a large combustion test facility which is capable of performing combustion test at design condition of the 75-tonf-class thrust chamber should be constructed as soon as possible.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.3
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• pp.237-243
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• 2010

In this study, the effect of the shape of a pintle(obstacle) on thrust-modulation performance and drag in a pintle rocket was investigated by a cold flow test and by computational fluid dynamics. Pintle movement caused a monotonic increase in the chamber pressure. Thrust generated by the pressure distribution on the pintle body was linearly changed to the chamber pressure, and this thrust was greater than that generated by the nozzle-wall pressure distribution. Because the shock pattern in the nozzle changes with the shape of the pintle body and pressure ratio, the thrust generated by the nozzle-wall pressure is not directly affected by chamber pressure. The drag due to the pintle(obstacle) can be minimized for a fully linear pintle shape, regardless of chamber pressure.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.294-298
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• 2001

Satellite propulsion system is employed for orbit transfer, orbit correction, and attitude control. The monopropellant feeding system in the low-earth-orbit satellite blowdowns fuel to the thrust chamber. The thrust produced by the thruster depends on fuel amount flowed into the combustion chamber. If the thruster valve be given on-off signal from on-board commander in the satellite, valve will be opened or closed. When the thrusters fire fuel flows through opened thruster valve. Instantaneous stoppage of flow in according to valve actuation produces transient pressure due to pressure wave. This paper describes transient pressure predictions of the KOMPSAT2 propulsion system resulting from latching valve and thrust control valve operations. The time-dependent set of the fluid mass and momentum equations are calculated by Method of Characteristics (MOC).

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.167-174
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• 2011

Solid propulsion systems have simple structures compared to other propulsion systems and are suitable to long-term storage. However the systems generally have limits on control of thrust levels. In this paper we suggest control algorithms for combustion chamber pressure of variable thrust solid propulsion systems using special nozzles such as pintle valve. For this we use a simple pressure change model by considering only mass conservation within the combustion chamber, design a classical algorithm and also a nonlinear controller using feedback linearization technique. Derived thrust equation and designe a thrust control model. We design the proportion-integral controller for linearizing about operating point. We also demonstrate the performance of controller model through numerical simulations.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.4
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• pp.18-25
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• 2011

Solid propulsion systems have simple structures compared to other propulsion systems and are suitable for long-term storage. However the systems generally have limits on control of thrust levels. In this paper we suggest control algorithms for combustion chamber pressure of variable thrust solid propulsion systems using special nozzles such as pintle valve. For the pressure control within the chamber, we use a simple pressure change model by considering only mass conservation within the combustion chamber, design a classical algorithm and also a nonlinear controller using the feedback linearization technique. Also we derive the equation of the thrust for an under-expanded one-dimensional nozzle and then design a proportional-intergral controller after linearizing the thrust model for an operating point. Finally, we demonstrate the performance of the controller through a numerical simulation.