• 열병합발전
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• s.59
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• pp.4-8
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• 2007

• KEPCO Journal on Electric Power and Energy
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• v.4 no.1
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• pp.19-24
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• 2018

The long-term research and development for the production of domestic blades has been consistently performed. As the direct and indirect results of its nationwide technologies in precision casting have been improved as well as maintenance costs for turbine machinery has been reduced. Whereas, there are still not a few concerns about the reliability of newly manufactured blades in spite of the quality certificate in metallurgical and mechanical properties. A spin tester is a machine that gives centrifugal loading to a rotating part, and its practical application is the overspeed test that is usually used to check the quality of products. A new spin rig has been constructed in KEPCO Research Institute for the purpose of evaluating the reliability of blades. In this paper, the test methodology for low cycle fatigue damage mechanism as well as the overspeed test for newly developed blades is described, and their reliability is evaluated too.

• 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.

• Journal of the Korean Society for Nondestructive Testing
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• v.14 no.3
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• pp.172-176
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• 1994

Interpreted is the geometric signal in the angle beam ultrasonic testing for the pin-finger type of turbine blade roots. The geometry of the blade roots is described and the reflection conditions for appearance of the geometric signal are proposed. The general equation for its beam path is derived and verified. As the results, it is found that the geometric signal is the back reflection front the ligament edge, and its position and amplitude can be determined from the dimension of blade root and the beam directivity of transducer.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.4
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• pp.10-18
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• 2007

A tested micro axial-type turbine consists of two stages and its mean radius of rotor flow passage is 8.4 mm. This turbine could be applied to a driver of micro power system, and its rotational speed in the unloaded state reaches to 100,000 RPM. The performance of this system is sensitive depending on the blade angles of the rotor and stator because it is operated in a low partial admission rate, so a performance test is conducted through measuring the specific output power and the net specific output torque with various blade angles on the nozzle, stator and rotor. The experimental results show that the net specific output torque is varied by 15% by changing the rotor blade angle, and the optimal incidence angle is about $10.3^{\circ}$.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.297-301
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• 2007

The blades of supersonic turbines with low aspect ratio are usually designed to have the same cross sectional shape in radial direction. The profile diameter definition of turbines may lead to produce unintended flow passage area variations resulting performance degradation. In this paper, the effects of profile diameter definition on the supersonic impulse turbine performance have been investigated. Computational results of three different profile diameters are compared. It has been found that flow passage area variation can be achieved according to designer's intention when blade profile is defined at rotor tip diameter. Furthermore, the turbine blade profile defined at rotor tip showed better performance than the others.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.43-48
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• 2010

Present study was conducted numerical analysis for velocity compound supersonic impulse turbine with the rotor overlaps, and the performance characteristics were analyzed through the numerical results. Tip overlap was more effective than hub overlap through the analysis. a case, overlap applied the hub and tip of the rotor, has the largest improvement for the turbine performance in parametric study cases. In case of overlap for the 2nd stage rotor, however, improvement of the turbine performance was not visibly large. Because, power generated in the 2nd stage was 22~23% of whole generated turbine power.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.397-400
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• 2011

MDO Optimization for a low pressure axial compressor rotor has been carried out to improve aerodynamic performance and structural stability. Global optimized solution was obtained from an artificial neural network model with genetic algorithm. Optimized rotor model has a high blade loading near hub and near zero incidence flow angle near tip region to reduce the incidence loss and flow separation at trailing edge region. Also the rotor shape is converged to a trapezoid shape to reduce the maximum stress occurred at the root of the blade. Numerical simulation results show that rotor has 87.6% rotor efficiency and safety factor over than 3.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1995.10a
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• pp.715-719
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• 1995

• Proceedings of the Korea Association of Information Systems Conference
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• 2001.05a
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• pp.299-317
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• 2001