• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.4
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• pp.25-31
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• 2013

A blisk with rotor shroud is usually adopted in LRE turbine to maximize its performance. However it experiences the severe thermal load and resulting damage during engine stating and stop. Shroud splitting is devised to relieve the thermal stress on the turbine rotor. Structural analysis confirmed the reduction of plastic strain at the blade hub and tip. However, split gap at the rotor shroud entails additional tip leakage and results performance degradation. In order to assess the effect of shroud split on the turbine performance, tests have been performed for various settings of shroud split. For the maximum number of shroud splitting, measured efficiency reduction ratio was 2.65% to the value of original shape rotor.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.4
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• pp.85-90
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• 2018

The objective of this paper is to observe effects of ignition position and time on ignition transition. A gaseous oxygen and liquid kerosene mixture is used as propellant with a shear-coaxial injector. In order to study the ignition delay time and combustion instability intensity, the pressure transducer was used. Sequences, excepting igniter operation time, were fixed to compare the ignition time only. Initial pressure peak and ignition delay time increased as the ignition time was delayed. Additionally, an unstable flame development zone was detected when the igniter was away from the injector.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.4
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• pp.55-65
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• 2020

In this paper, development and acceptance test results of 75-tonf class liquid rocket engine gas generators are described. Up to now, more than 330 times and cumulative time of 7,000 seconds gas generator autonomous tests have been carried out with 44 gas generator models. Through the tests it was verified that 75 tonf gas generator shows very reliable and reproducible characteristics in terms of chamber pressure, combustion efficiency, pressure loss, combustion stability, burnt gas temperature, and etc. 5 gas generators which are the last series of 75 tonf gas generator for the Korea Space Launch Vehicle II, will be manufactured until end of 2019 and their acceptance tests will be executed at the first half of 2020.

• Journal of the Korean Institute of Gas
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• v.27 no.3
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• pp.108-115
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• 2023

Although hydrazine is an excellent liquid propellant, caution is required during storage and handling due to its high toxicity and reactivity. Safety guidelines should be established in consideration of the chemical reactivity by unintended leakage. In this study, the status of hydrazine facilities at launch site and safety standards for storing and handling were investigated and then, the reactivity between chemicals and hydrazine was analyzed. As a result of the analysis, hydrazine has reactivity with the exception of fuel oil. This paper emphasizes the imperative nature of constructing a dedicated hydrazine storage facility. Ensuring compatibility between hydrazine and the materials used in storage containers and handling equipment is crucial to prevent undesired reactions that could compromise safety. It was intended to be used as basic data to secure the range safety when handling hydrazine.

• Aerospace Engineering and Technology
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• v.13 no.2
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• pp.160-166
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• 2014

The shutoff valve of a Liquid Rocket Engines (LRE) controls the flow of propellant between turbo-pump and combustion devices of LRE using pilot pressure and spring force. The shutoff valve is closed when the pilot pressure is removed from the diaphragm type actuator. During designing process of life cycle is when should be analyzed according to the characteristics of forces with respect to the opening and closing of diaphragm actuator. A valve has been designed to adjust the control pressure which is required to open a poppet and to determine the working fluid pressure at which a valve starts to close. During flow capacity test under room temperature as a part of life cycle tests, the leakage in diaphragm was occurred due to the leakage of sheet welding sections. The operating cycle of the diaphragm type actuator is about 61 times with 22 MPa of pilot pressure.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.8
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• pp.1024-1029
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• 2012

As DME (Dimethyl ether) is the one of the future possible massive energy sources synthesized from natural gas, KOGAS has been doing to obtain overseas resources to meet the domestic needs. and tried to build new DME FPSO ship. This paper presents that it can help for the DME storage tank designers and storage management engineers doing proper work by understood the evaporation phenomena and pressure change of DME by thermal intake in storage tank. The experimental result shows that the evaporation rate and pressure are increased with higher liquid filling level. The proper DME liquid filling level in tank is obtained as lower than full 98% volume of tank in case of storing longer than a day, because the pressure is increased rapidly with full 98% filled level of storage tank.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.12
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• pp.41-47
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• 2006

A liquid rocket thrust chamber should have a high confidence in its combustion performance and combustion stability. Expecially, the injector of which function is spraying and mixing propellants plays an important role in getting the confidence. This study was carried out to evaluate combustion stability of a double swirl coaxial injector by using the model similarity method. Besides, in case of a baffle which was used to improve combustion stability, the length and gap effects of the baffle were investigated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.8
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• pp.99-106
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• 2003

Geometrical design variables are numerically investigated to improve aerodynamic performance of the supersonic impulse turbine of a turbopump in a liquid rocket engine. Aerodynamic redesign was performed for maximization of the blade power. Four design variables considered are blade angle, blade thickness and radii of upper and lower arc blade with appropriate constraints. A fast Navier-Stokes solver was developed and Chien's k-$\varepsilon$ turbulence modelling was used for turbulence closure. In initial shape, a flow separation was found in the middle of blade chord. However, it disappeared in final shape via its geometrical design variable change. About 3.2 percent of blade power was increased from this research.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.255-258
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• 2002

Liquid rocket engines using liquefied natural gas (LNG) or methane as a fuel is known to have several good characteristics, such as high specific impulse compared to other hydrocarbon fuels, environment-friendly exhaust gas, low production cost, and re-usability with low soot generation in the cooling channel. In this study, experimental combustion chambers capable of using LNC and $CH_{4}$ are being researched through experimental firing tests, and within easy range of eyes' inspection, there are the periodical existence of soot or discoloration in the chamber wall surface. This result means that mixture ratio of oxidizer and fuel fluctuates periodically between outer-row injectors in the mixing head in the circumferential direction. Therefore, based on this phenomenon, the variation of mixture ratio near the chamber wall caused by the spill pattern of a shear coaxial injector was analyzed quantitatively and the thermal heat flux Into the cooling channel is modified. Then, the calculated and modified results are compared with the measured ones.

• Aerospace Engineering and Technology
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• v.11 no.1
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• pp.78-83
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• 2012

Generally, the first stage of a launch vehicle requires high thrust to achieve a mission. We can use one high thrust level engine or a clustered engine system which made of several small thrust level engines to make high thrust. The first stage propulsion system of KSLV-II has 300tf thrust to satisfy the mission. But it is impractical to make high thrust by one engine at this moment in time. So we should cluster four 75tf class engines which can be applied to make a required thrust for the first stage propulsion system. This article deals with the concept of the first stage clustered engine arrangement of KSLV-II.