• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.145-148
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• 2008

Korea Aeronautics Research Institute (KARI) is developing a turbo pump that has 1-stage impulse turbine and relatively high tip clearance for safety. The objective of this research is to investigate the effect of reaction on tip clearance loss in axial turbines. Both cascades were tested in a subsonic wind tunnel. In each cascade, total pressure was measured for tip clearance ranging from 1% to 20% of chord. In results, increasing tip clearance, total pressure loss in reaction turbines is continually increased but impulse turbines keep almost same level of mass averaged total pressure loss. When tip clearance becomes more than 10% of chord, mass-averaged total pressure loss in impulse turbines is less than in reaction. This means that when tip clearance is more than 10% of chord, impulse turbines have better efficiency than reaction turbines.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.33 no.3
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• pp.234-240
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• 1997

터보 챠저의 반동도와 터빈 노즐유량의 변화를 행하여 엔진의 성능을 향상시킬 수 있었다. 터빈의 에너지 손실과 그 영향을 미치는 반동도 및 터빈 입구의 유로의 변화, 그리고 블레이드에서 역 유동에 대한 개선 조건도 제시하였다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.12
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• pp.1391-1398
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• 2011

Design and performance analysis of a steam turbine for variations of degree of reaction were performed by computer simulation. Design parameters such as blade angles, exit areas, and heights of the nozzle and moving blade were represented as functions of the degree of reaction. The main performance factors such as turbine power, diagram efficiency, and axial thrust were also expressed in terms of the degree of reaction. For further information about the design and performance, the blade angles and main performance factors were investigated as functions of the flow coefficient. The turbine power and diagram efficiency reached a maximum value for a given degree of reaction and flow coefficient, and the symmetric shape of the moving blade showed distortion as the degree of reaction was increased.

• Journal of the Korean Society of Propulsion Engineers
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• v.5 no.2
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• pp.24-31
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• 2001

An axial-type turbine design technology is developed. In order to design one-stage turbine, the preliminary design method is applied, and then design parameters are chosen after analyzing gas properties within the turbine passage using the streamline curvature method. Stator blade is designed using C4 profile, and rotor blade is designed using shape parameters. Stator is manufactured as an integral type and rotor is manufactured to be disassembled from the disc for changing blade incidence angle. The output power from the rotor is measured with various RPM and input power. Experimental results show that the maximum efficiency of turbine rotor is obtained on the design point, and the output power is proportionally decreased with the negative incidence angle even the test turbine is a reaction turbine. The efficiency of turbine rotor is decreased to 5% by $7.5^{\cire}$ negative incidence angle from the designed value.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.4
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• pp.99-105
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• 2002

The performance test of an axial-type turbine is carried out with various axial gap distances between the stator and rotor. The turbine is operated at the low pressure and speed, and the degree of reaction is 0.373 at the mean radius. The axial-type turbine consists of ons-stage and 3-dimensional blades. The chord length of rotor is 28.2mm and mean diameter of turbine is 257.56mm. The power of turbo-blower for input power is 30kW and mass flow rate is $340m^3$/min at 290mmAq static-pressure. The RPM and output power are controlled by a dynamometer connected directly to the turbine shaft. The axial gap distances are changed from a quarter to three times of stator axial chord length, and performance curves are obtained with 9 different axial gaps. The efficiency varies about 8% of its peak value due to the variation of axial gap on the same non-dimensional mass flow rate and RPM, and experimental results show that the optimum axial gap is 1.6-1.9Cx.

• Aerospace Engineering and Technology
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• v.1 no.1
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• pp.163-172
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• 2002

The turbine system composed of a nozzle and a rotor is used to drive turbopumps while gas passes through the nozzle, potential energy is converted to kinematic energy, which forces the rotor blades to spin. In this study, an aerodynamic design of a turbine system is investigated using compressible fluid dynamic theories with some pre-determined design requirements (i.e.,pressure ratio, rotational speed, required power etc.) obtained from a liquid rocket engine (L.R.E.) system design. For simplicity of a turbine system, impulse-type rotor blades for open type L.R.E. have been chosen. Usually, the open-type turbine system requires low mass flow rate compared to the close-type system. In this study, a partial admission nozzle is adopted to maximize the efficiency of the close-type turbine system. A design methodology of the a turbine system has been introduced. Especially, a partial admission nozzle has been designed by means of simple empirical correlations between efficiency and configuration of the nozzle. Finally, a turbine system design for a 10 ton thrust level of L.R.E is presented.

• The KSFM Journal of Fluid Machinery
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• v.15 no.1
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• pp.64-69
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• 2012

Currently axial flow compressor is used primarily in a large power generation gas turbine. In this paper,the main factors to be considered when designing a axial flow compressor were compared to those of a small power generation gas turbine(DGT-5). The main design parameters was examined in the aspect ratio, solidity, as well as reaction, diffusion factor, incidence angle, etc. The results in case of a small compressor are showed a regular pattern but there were not found any specific design patterns for a large class compressor.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.8
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• pp.107-114
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• 2003

The effect of uncertainties caused by measured parameters, which are propagated to the uncertainty of total-to-total efficiency, are analyzed from a turbine performance test. The degree of reaction is 0.373 at the mean radius on a tested 3-D axial type turbine, and the performance test is conducted at the low pressure and cold temperature status. The uncertainty of turbine inlet and exit total pressure shows the strong propagation effect to the uncertainty of total-to-total efficiency. This means that a high precision pressure measuring system is required to reduce the uncertainty propagated by the pressure. In the uncertainty portion of each measured parameters to the uncertainty of total- to-total efficiency, the uncertainty by torque is the highest and the uncertainty by RPM is the lowest. In case of the total pressure, the effect of the uncertainty by torque is increased with the increasing RPM. The uncertainty of total pressure at the turbine exit is more important than that at the turbine exit.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.05a
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• pp.123-126
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• 2003

The uncertainties generated by measurement parameters are propagated to the uncertainty of total-to-total efficiency on an experiment. The effect of uncertainties’ propagation are analyzed through a turbine performance test. A tested 3-D axial type turbine has a 0.373 degree of reaction at the mean radius and the performance test is conducted at the low pressure and cold temperature status. The uncertainty of turbine inlet and exit total pressure shows the strong propagation effect to the uncertainty of total-to-total efficiency. This means that a high precision pressure measuring system is required to reduce the uncertainty propagated by the pressure. In the uncertainty portion of each measurement parameters to the uncertainty of total-to-total efficiency, the uncertainty by torque is the highest and the uncertainty by RPM is the lowest. In case of the total pressure, the effect of the uncertainty by torque is increased with the increasing RPM. The uncertainty of total pressure at the turbine exit shows more influence to the results than that at the turbine.