• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.12
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• pp.933-938
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• 2009

Hot test of a full-scale turbopump for a 30-ton-thrust liquid rocket engine was carried out. The turbopump is composed of an oxidizer pump, a fuel pump, and a turbine on a single shaft. Model fluid was used in the test, that is, hot air for the turbine and water for the pumps. The turbopump was operated stably at full speed for 120 seconds. In terms of performance characteristics of pumps and turbine, the results from the turbopump assembly test are compared with those from the turbopump component tests which were performed at about half of the design rotational speed.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.1
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• pp.19-28
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• 2011

As a preview study, present research analysed the performance characteristics of a velocity compound supersonic impulse turbine with the rotor overlaps before adapting the overlap has the best turbine performance. This research was conducted for the turbine with square cross-section nozzles instead of axisymmetric nozzles and wrap around nozzles. Through 3-dimensional flow analysis for the turbine by a commercial flow analysis package, tip overlap case was more effective to improve the turbine performance than case hub overlap, and overlap case applied the hub and tip of the rotor had the largest improvement for the turbine performance in the cases. In case of overlap for the 2nd stage rotor, improvement of the turbine performance was not visibly large. Because, generated power in the 2nd stage is 22~23% of whole generated turbine power.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.4
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• pp.26-35
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• 2004

As part of thrust control technology research on turbopump-fed type liquid-propellant rocket engine system, the low frequency dynamic characteristics of turbopump was investigated. It can be described that a turbopump system has a 1st-order lag element. When the value, which was resulted by subtraction of the variation of turbine moment with respect to the variation of revolution number from the variation of pump moment with respect to the variation of revolution number, was positive, the time constant of the 1st-order lag element was positive which stood for a stable system. Increasing the above-mentioned valve within positive range leaded to the increase of response and to the decrease of controllability.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.5
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• pp.109-115
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• 2004

A 1-D system design program has been developed for the preliminary design of the turbopump system in liquid rocket engines, which use LOx and kerosene as propellants. Gasgenerator cycle and staged combustion cycle were considered as turbopump type liquid rocket engine systems. In the system analysis, mass flow balance, thrust, specific impulse, mixture ratios, turbopump power, and turbine expansion ratio of engine system were analyzed. Results show that most of the parameters agree well with real engine parameters except gasgenerator. Therefore, the l-D system design program developed in this study can be used to derive the preliminary design parameters of a turbopump with any thrust level liquid rocket engine.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.4
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• pp.41-47
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• 2011

Turbopump, which is a part of 75 ton open cycle liquid rocket engine has a super sonic impulse turbine. This paper investigated the leading edge thickness effect on the turbine performance experimently. Two rotors were tested with the different leading edge thickness. The ratios (rotor thickness to Pitch) are 1.9 and 1.4 times to 30 ton turbine rotor. As a result, a rotor with 1.4 times ratio had a 1.5% higher efficiency gain than a rotor with 1.9 times ratio. The pressure ratio with the maximum efficiency on the same rotational speed was increased to the full expansion ratio of nozzle.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.33-36
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• 2010

Lots of studies about turbine loss have been done especially about tip leakage loss. But these studies deals with small tip clearances which is less than 5 percent chord. Now, like turbopumps, small turbines have larger tip clearance and it is hardly found related papers in open literature. On this study, with varying tip clearance 1% to 20% chord, loss is measured under inlet velocity at 30m/s and Reynolds number based on chord at 210000. It is found that maximum loss coefficient is 0.113 at 10% clearance, and when tip clearance is larger than 10%, loss is not linearly increased anymore.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.117-122
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• 2012

A blisk with rotor shroud is usually adopted in LRE turbine to maximize its performance. However it experiences severe thermal load and resulting damage during engine stating and stop. Shroud splitting is devised to relieve 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.25 no.5
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• pp.1-9
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• 2021

As part of the commercialization research of small gas turbine engines, starting and normal operation control logic research of small gas turbine engine was conducted. It was investigated how the igniter, starting motor and fuel pump/valve are controlled during the ignition and normal operation process and it was applied to the prototype engine control unit(ECU) of the small gas turbine engine for commercialization research. Based on the ground test results, an ECU for flight test is being developed, and after completion of the development, an altitude test will be performed through an altitude test facility of Korea Aerospace Research Institute.

• Journal of KSNVE
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• v.4 no.3
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• pp.273-277
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• 1994

1990년 7월 이후 #2 베어링에서 발생한 오일 휩 현상을 감지하고서도 그 주원인을 일반적으로 흔히 발생하는 사항에서만 해결방안을 찾으려 노력한 결과 3년 반의 시간이 경과되었고, 뜻하지 않게도 저널 직경의 불균일에 의한 오일 휩 현상임 을 뒤늦게 알게 되었다. 철저한 점검의 필요성을 강조하지 않을 수 없다. 증기터빈 의 Overhaul 작업완료 후 Oil Flusning 절차가 있는데 이 Oil Flusning 방법에 문제 가 있다. 보통은 작업완료후 로터를 정지한 상태에서 베어링 앞에 Oil Strainer(Fine Mesh)를 설치하고 오일 펌프를 기동하여 Flushing을 하는데 이때 Strainer를 통과한 작은 이물질이 베어링내에 축적되었다가 터빈 기동시 이 이물질과 로터가 접촉되어 저널이 손상되게 된다. 인천화력3호기 #2 베어링의 오일 휩을 일으키게 한 저널의 편마모 현상도 이와같은 경우임에 틀림없다. 왜냐하면 '90, O/H시 #2 베어링 저널의 직경은 원통형이었기 때문이다. 따라서 Oil Flusning은 터빈 구조상 불가능한 경우 도 있겠지만 베어링 by-pass Oil Flushing 시스템으로 개조 운영되어야 저널 및 베어링 마멸현상을 제거할 수 있고 이로인한 오일 휩 현상도 예방할 수 있을 것으로 판단된다.

• The KSFM Journal of Fluid Machinery
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• v.14 no.1
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• pp.55-60
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• 2011

Numerical analyses of a turbine redesigned to achieving the weight reduction by equipping square nozzles and the original turbine have been conducted and the results have been compared. The results show that the turbine with square section nozzles has more even flow distribution at the first row rotor inlet and less inactive areas but the loss induced by wake is increased. Despite the wake loss, the newly designed turbine shows better performance than the original one. It has also been found that the turbine performance can be improved by reshaping its stator and second row rotor.