• Proceedings of the KSME Conference
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• 2001.06e
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• pp.813-818
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• 2001

The flow characteristics of the vaned diffuser were complicated with geometric shapes. We have studied the effects of various vaned diffuser configurations, such as divergence angles and rectangular and conical cross-section shapes. Numerical analyses are carried out for the diffuser and casing. The pressure recovery coefficient was calculated to estimate the performance of the diffuser, and then compared with the measure data. Results show that the shapes and the divergence angles of the diffuser strongly influence on the performance of the small-size turbo-compressor.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.548-551
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• 2010

A 150 lbf-thrust class micro turbojet engine has been developed. The engine could be applied to power plant for small aviation vehicle such as UAV, decoy and anti-radar missile and was designed with concepts that has small size, low-cost and high performance. A prototype was manufactured and performed the ground static test and high altitude test. This paper outlines the features and layout of 150 lbf turbojet engine and also describes the design characteristics and test results of the engine and components.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.807-812
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• 2001

The effects of casing shapes on the interaction of the impeller and volute in a small-size turbo-compressor are investigated. Numerical analysis is conducted for the compressor with circular and single volute casings from inlet to discharge nozzle. In order to predict the flow pattern inside the entire impeller, vaneless diffuser, and casing, calculations with a multiple frame of reference method between the rotating and stationery parts of the domain are carried out. For incompressible turbulent flow fields, the continuity and three-dimensional time-averaged Navier-Stokes equations are employed. To predict the performance of two types of casings, the static pressure and loss coefficients are obtained with various flow rates. Also, static pressure distributions around casings are studied for different casing shapes, which are very important to predict the distribution of radial load.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.711-717
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• 2017

Measurements of the moment of inertia of a small turbocharger rotor were studied. A measuring device was manufactured using the trifilar method and the moment of inertia of the calibration rotor was measured to verify the device. The coefficient of variation was 0.43% and the error was 0.75%. The results showed that the device is suitable for measuring the moment of inertia of a turbocharger rotor. Next, the moment of inertia for two turbine rotors and compressor wheels was measured. Those for the turbine rotors showed precise and accurate results in that the coefficients were under 1.0% and the errors were under 3.0%. On the other hand, those for the compressor wheel were precise but inaccurate in that the coefficients were under 1.0% and the errors were over 24.4%. Therefore an indirect method for the compressor wheel was suggested. The results showed that the coefficients were under 1.2% and the errors were under 7.88%.

• Journal of Advanced Navigation Technology
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• v.20 no.3
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• pp.190-195
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• 2016

In this paper, Propose to prevent compressor surge and improve the transient response of the fuel flow control system of turbojet engine. Turbojet engine controller is designed by applying Fuzzy-PID control algorithm. To prevent any surge or a flame out event during the engine acceleration or deceleration, the Fuzzy-PID controller effectively controls the fuel flow input of the control system. Fuzzy-PID results are used as the fuel flow control inputs to prevent compressor surge and flame-out for turbo-jet engine and the controller is designed to converge to the desired speed quickly and safely. Using LabVIEW to perform computer simulations verified the performance of the proposed controller. Response characteristics pursuant to the gain were analyzed by simulation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1997.11a
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• pp.23-23
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• 1997

다목적으로 활용할 수 있는 분리축 방식의 터보축 엔진 개발을 위한 정상상태 해석 프로그램의 개발과 함께 동일 형식의 가스터빈엔진 시험장치를 이용한 실험을 통해 프로그램의 해석결과와 비교, 그 타당성을 입증하였다. 실험에 이용된 시험장치는 1단 원심형 압축기, Can형 연소기, 1단 Radial형 압축기 터빈 및 동력터빈으로 구성되어 있으며 출력은 3상 교류발전기를 통해 획득된다. 해석에 사용된 주요 구성품의 성능곡선은 시험장치 제작자로부터 획득된 자료를 이용하였으며, 경우에 따라 시험장치를 이용한 실험을 통하여 보정하였다. 시험장치를 이용한 실험결과를 프로그램 해석결과와 비교한 결과, 시험장치의 운용제한에 의해 실제 자동영역이 제한되기는 했으나, 압력비, 출력 등 주요 변수들에서 10% 미만의 오차를 보였다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.12
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• pp.1031-1038
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• 2002

The effects of casing shape on the performance and interaction between the impeller and casing in a small-size turbo-compressor are investigated. Numerical analysis is conducted for the compressor with circular and single volute casings from inlet to discharge nozzle. In order to predict the flow pattern inside the entire impeller, vaneless diffuer and casing, calculations with multiple frames of reference method between the rotating and stationery parts of the domain are carried out. For compressible turbulent flow fields, the continuity and three-dimensional time-averaged Wavier-Stokes equations are employed. To evaluate the performance of two types of casings, the static pressure and loss coefficients are obtained with various flow rates. Also, static pressure distributions around casings are studied for different casing shapes, which are very important to predict the distribution of radial load. To prove the accuracy of numerical results, measurements of static pressure around casing and pressure difference between the inlet and outlet of the compressor are peformed for the circular casing. Comparisons of these results between the experimental and numerical analyses are conducted, and reasonable agreement is obtained.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.04a
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• pp.11-11
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• 1998

다목적으로 활용할 수 있는 터보축 엔진의 개발을 위한 정상상태 및 동적모사 프로그램을 개발하였다. 개발비, 개발시간, 개발위험도의 절감을 위해 가스발생기 부분은 성능이 잘 알려진 기존의 터보제트 엔진을 활용하였으며 약 3000hr 이상의 수명을 확보하기 위해 터빈재질을 교체하고, Larson-Miller 곡선을 이용하여 최대회전속도와 최대 터빈 입구온도를 각각 35000 RPM과 1140 K의 결정하였다 추가되는 동력터빈의 구성품 성능선도는 압축기 터빈 성능선도를 축척하여 사용하였다. 정상상태 성능해석에는 유량 및 일평형 방정식을 이용하였으며, 동력터빈이 각각 73%, 80%, 90%, 100% RPM일 때 가스발생기를 75%(24500 RPM)에서 100%(35000 RPM)까지 5% 간격으로 나누어 계산을 수행하였다.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.777-782
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• 2000

The flow fields in the volute casing of a small-size turbo-compressor at different flowrate (design point ${\pm}20%$) are studied by numerical analysis. The governing equations for three-dimensional steady viscous flow are solved using SIMPLE algorithm with commercial code of STAR-CD. Numerical results show that the three-dimensional flow pattern inside the volute casing of a small-size turbo-compressor is strongly influenced by secondary flows that are typically created by the curvature or the casing passages. The flow pattern in the casing also affects the performance of the turbo-compressor. In order to elucidate the loss mechanism through the volute, we prepared the secondary flow, velocity magnitude, and static pressure distribution at the four cross-sectional planes of the casing.

• Journal of Advanced Navigation Technology
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• v.18 no.2
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• pp.107-113
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• 2014

In this paper, controller Propose to prevent compressor surge and improve the transient response of the fuel flow control system of turbojet engine. Turbojet engine controller is designed by applying Artificial Neural Network PID control algorithm and make an inference by applying Artificial Neural Network Error Back Propagation Algorithm. To prevent any surge or a flame out event during the engine acceleration or deceleration, the ANN PID controller effectively controls the fuel flow input of the control system. ANN PID results are used as the fuel flow control inputs to prevent compressor surge and flame-out for turbo-jet engine and the controller is designed to converge to the desired speed quickly and safely. Using MATLAB to perform computer simulations verified the performance of the proposed controller. Response characteristics pursuant to the gain were analyzed by simulation.