• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1088-1092
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• 2017

In this study, a comparison of dynamic pressure data measured in hot-firing tests of liquid rocket engine gas generators with different types of dynamic pressure sensors is presented. The dynamic pressure sensors of different types and manufacturers have exhibited different dynamic pressure due to the influence of thermal shock. However, for the characteristic frequencies and RMS(root mean square) values which are important factors for the analysis of combustion instability, the differences between sensors have been found to be negligible.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.5
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• pp.91-96
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• 2004

An optimal design of the gas generator for Liquid Rocket Engine (LRE) was conducted. A fuel-rich gas generator in open cycle turbopump system was designed for 10ton in thrust with RP-1/LOx propellant. The optimal design was done for maximizing specific impulse of thrust chamber with constraints of combustion temperature and for matching the power requirement of turbopump system. Design variables are total mass flow rate to gas generator, O/F ratio in gas generator, turbine injection angle, partial admission ratio, and turbine rotational speed. Results of optimal design provide length, diameter, and contraction ratio of gas generator. And the operational condition predicted by design code with resulting configuration was found to maximize the objective function and to meet the design constraints. The results of optimal design will be tested and verified with combustion experiments.

• Journal of environmental and Sanitary engineering
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• v.15 no.4
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• pp.4-13
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• 2000

산업공정에서 배출되는 대기오염물질 및 유독성가스를 제거하기 위한 방법에는 여러 가지가 적용되고 있으나, 본 연구에서는 충전탑을 이용한 흡수원리로써 오염물질을 처리하는데 후력학적 특성에 대해서 연구하였다. 즉 환경보호와 화학공업에서 에너지 절약 측면에 충전탑의 사용이 증가되고 있으며, 충전물의 재료로는 플라스틱, 금속 및 세라믹 등으로 제작되며 종류로는 VSP-ring, Hiflow-ring, Hackette, Top-packing, Envi-pac 등이 있고 사용범위는 정류와 증류, 흡수 및 탈착과 액체와 액체의 추출공정 등에 효율적으로 사용되고 있다. 산업현장에서는 과거에 주로 사용되어온 Intalox-saddle, Rasching-ring, Pall-ring 등의 재래적 충전물은 압력손실과 물질전달, 에너지 절약 및 효율성이 좋은 격자형 충전물의 개발로 인하여 점점 사용이 감소되고 있는 추세이며, 최근에는 합성수지로 제조된 충전물 NSW-ring, Hiflow-ring, Envi-pac 등은 실험 결과에 의해서 재래적인 충전물 Raschig-ring과 Pall-ring보다 높은 상대적인 공간체적과 충전높이에 따른 낮은 압력손실과 함께 높은 부하 한계치에 대하여 효율적이고 가벼운 분리작용에 의한 수력학적 특성이 증명되어졌다. 격자형 충전물이 산업에 적용되기 위해서는 압력손실과 액체함량, 부하 한계치 가스상 또는 액상 물질전달의 특성을 규명하는 것이 중요하다. 따라서 본 연구에서는 가수와 액체의 역류흐름에 의한 수력학적 특성과 물질전달 실험결과를 나타내었다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.05a
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• pp.211-217
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• 2003

A liquid rocket engine(LRE) Using LO$_2$/LNG(Liquefied Natural Gas) propellants was experimentally evaluated. The purpose of this study was to investigate the performance of the LO$_2$/LNG rocket combustor that is composed of three sect ions(igniter spacer, cylinder and nozzle section), especially focused on the influence of regenerative cool ing effect in association with the phase of regenerative coolant Series of tests were conducted under the conditions of water cool ing and regenerative cool ing with LNG in the cylinder section and independent cool ing with water in the igniter spacer and nozzle sections. Parametric studies on the variation of a chamber pressure and mixture ratio were undertaken. In addition, effect of propellant(LNG) composition and its enthalpy on the performance is examined.

• 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.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.10
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• pp.56-60
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• 2006

It is essential to predict thermodynamic properties of combustion gas with respect to a propellant mixture ratio for the development of a gas generator for a liquid rocket engine. The present study shows the temperature measurement of exit combustion gas as a function of a mixture ratio through the series of combustion tests of a fuel-rich gas generator with liquid oxygen and Jet A-1. The measurements of dynamic and static pressures, and combustion gas temperatures allowed the estimation of thermodynamic properties like a specific heat ratio, a gas constant, and a constant pressure specific heat of the combustion gas. The comparison of the experimental results with predictions made by interpolation parameters obtained from the modification of the chemical equilibrium code indicates that the interpolation method calibrated using the temperature measurements can be utilized as an effective tool for the initial design of a fuel-rich gas generator.

• Journal of the Korean Institute of Gas
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• v.2 no.3
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• pp.37-48
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• 1998

A cryogenic liquid stored in the closed cryogenic tank has been studied at various liquid levels. The change of pressure, temperature, and liquid-vapor ratio in the tank depended on the liquid levels. The various phenomena were shown at different liquid levels as follows: (1) liquid level was increased with condensation of vapor: (2) liquid was vaporized in spite of liquid level going up for a certain initial period and then condensation of vapor occurred at higher pressure; (3) liquid was vaporized without liquid level change; (4) liquid was vaporized with liquid level decreasing. If the tank is full with cryogenic liquid, it is extremely dangerous because of soaring the pressure. Therefore the tank must be filled with $90\%$ liquid according to the safety rules. If the tank was filled with $0\%$ ullage, the pressure increment as high as 80bar during first 5 days. With $90\%$ liquid level, however, the pressure was increased as low as 1.5bar in the same period. No matter what the liquid level is, it is very dangerous if the tank is locked-up with filled cryogenic liquid for a long time.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.8
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• pp.805-811
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• 2009

An oxidizer pump of a turbopump for a 30-ton class gas generator cycle engine was tested in the medium of liquid oxygen. The turbine was driven by cold hydrogen gas in the test. The oxidizer pump was operated stably at both design and off-design conditions, satisfying the performance requirements. The pump head coefficient from the liquid oxygen test was 2~3% lower than that from the water test. The power required to run the oxidizer pump was well balanced with the power produced by the turbine.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.20-23
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• 2011

The spray and atomization characteristics of swirl coaxial injectors which use gas methane and LOx as propellants are investigated experimentally with a recess length variation. Mass distribution and spray angle are measured by a patternator and droplet size to find atomization characteristics are measured by GSV(Global Size and Velocity) system. As a result, when the liquid sprayed, the spray angle decreased and the atomization characteristic was improved with the recess length increase. When the gas and liquid injected simultaneously, the spray angle was decreased and the atomization characteristic was improved comparing to only the liquid injection.

• Korean Chemical Engineering Research
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• v.51 no.4
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• pp.500-505
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• 2013

In this study, we investigated the kinetics of gas hydrate formation in the presence of ionic liquid (IL). Hydroxyethyl-methyl-morpholinium chloride (HEMM-Cl) was chosen as a material for the promotion effect test. Phase equilibrium curve for $CH_4$ hydrate with aqueous IL solution was obtained and its induction time and consumed amount of $CH_4$ gas were also measured. Aqueous solutions containing 20~20,000 ppm of HEMM-Cl was prepared and studied at 70 bar and 274.15 K. To compare the measured results to those of the conventional promoter, sodium dodecyl sulfate was also tested at the same condition. Result showed that the hydrate equilibrium curve was shifted toward higher pressure and lower temperature region. In addition, the induction time on $CH_4$ hydrate formation in the presence of IL was not shown. The amount of consumed $CH_4$ was increased with the whole range of tested concentration of IL and the highest consumption of $CH_4$ happened at 1,000 ppm of HEMM-Cl. HEMM-Cl induced and enhanced the $CH_4$ hydrate formation with a small amount of addition. Obtained result is expected to be applied for the development of technologies such as gas storage and transport using gas hydrates.