• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.5
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• pp.52-61
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• 2015

This paper performed a numerical study to analyse the transient performance behavior of a turbofan engine with variable inlet guide vane (IGV) and bleed air schedules. The low bypass ratio mixed flow turbofan engine was considered in this study. For modeling the compressor performance with IGV, the performance maps were generated by using a one-dimensional meanline analysis and feed to the engine simulation program. The IGV and bleed air according to the rotating speed were scheduled to satisfy 10% of surge margin at steady-state condition. The transient engine performance analysis was conducted with the schedules. The engine with IGV schedule showed a higher surge margin and lower turbine inlet temperature than the engine with bleed air schedule during the transient period.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.4
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• pp.1-8
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• 2012

In this study, numerical method, stage stacking method based on the result of numerical method and scaled stage stacking method have been applied to predict the performance of a multi-stage axial compressor with inlet guide vane. The results obtained through three different methods for off-design conditions were compared with performance test data. And the effect the angle of variable inlet guide vane was also investigated. The three-dimensional numerical simulation has been performed by using flow analysis program, $FLUENT^{TM}$ 6.3 and the performance prediction based on the stage stacking method has been performed with compressor analysis code from NASA.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.4
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• pp.23-32
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• 2012

The present study is aimed to develop an integrated performance analysis approach for the application of a compressor with variable inlet guide vane (VIGV) and vairable stator vane (VSV) in a small turbofan engine. For the integrated analysis approach, an engine performance analysis program, NPSS and a computer program used for predicting of axial flow compressor performance based on stage stacking method, STGSTK were linked with an optimisation package, Isight. This enables off-design performance analysis for the turbofan engine with VIGV and VSV hence provides the capability to predict stable operation condition of the engine with acceptable surge margin.

• The KSFM Journal of Fluid Machinery
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• v.5 no.3 s.16
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• pp.46-53
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• 2002

This paper reports an experimental investigation on a centrifugal compressor with the adjustable inlet guide vane. The compression system is composed of a radial impeller, a vaneless diffuser, and an IGV. The results have shown that surge line on the performance map is affected by the amount of prewhirl and the prewhirl has an effect on transient region between rotating stall and surge. The surge lines have been shifted toward the lower flow region with the increased positive prewhirl and the higher flow region with the increased negative prewhirl. During the unsteady performance test, it was also found that the transient region was reduced with the increased negative prewhirl, and weak signals of rotating stall were detected just before surge as the positive prewhirl was increased.

• The KSFM Journal of Fluid Machinery
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• v.7 no.3 s.24
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• pp.23-31
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• 2004

An experimental study on the performance and instability development characteristics of a centrifugal compressor equipped with an adjustable inlet guide vane has been performed with varying guide vane angles. The test was conducted at the design speed of 20,800 rpm for 6 guide vane angles : $-30^{\circ},\;-20^{\circ},\;10^{\circ},\;0^{\circ},\;10^{\circ},\;20^{\circ},\;30^{\circ}$. Unsteady pressures were measured using high-frequency pressure transducers at the inducer to investigate the instability phenomena such as rotating stall and surge inside the compressor. From the unsteady measurements, it is found that the transient process from rotating stall to surge was mainly affected by inlet guide vane angles. The results of the present study can be applied to the instability control of the centrifugal compressors using a adjustable inlet guide vane.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.8
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• pp.580-588
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• 2009

This paper summarizes the experimentally-measured performance of small-scale, vertical-axis wind turbine for the purpose of improving the aerodynamic efficiency and its controllability. The turbine is designed to have a Savonius-Type rotor with an inlet guide-vane and an side guide-vane so that it achieves a higher efficiency than any lift- or drag-based turbines. The main design factors for this high-efficient, vertical wind turbine are the number of blades (Z), and the aspect ratio of Height/Diameter (H/D) among many. The basic model has the diameter of 580mm, the height of 464mm, and the blade number of 10. The maximum power coefficient of 0.50 was experimentally measured for the above-mentioned specifications. The inlet-guide vane ensures the maximum efficiency when the angle of attack to the rotor blade lies between $15^{\circ}$ and $20^{\circ}$. This experimental results for the vertical-axis wind turbine can be applied to the preliminary design of turbine output curve based on the wind characteristics at the proposed site by controlling its aerodynamic performance given as a priori.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.3
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• pp.237-242
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• 2014

Surge phenomenon can be occurred in a compressor when the performance of turbofan engine for an aircraft is changed considerably such as take-off phase. This study is aimed to avoid surge phenomenon. This paper propose the PID and Fuzzy control System for the turbofan engine with control inputs, the VIGV(Variable Inlet Guide Vane) in closed loop, and the fuel mass flow in open loop. We design the Dynamic modeling, NPSS S-function, which is connection block of simulink between NPSS(Engine analysis program) and Simulink. Finally, we certify the performance to prevent a serge phenomenon in the VIGV control system using the both methods, PID and fuzzy.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.7
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• pp.539-546
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• 2013

Surge phenomenon can be occurred in a compressor when compressor performance of turbofan engine for an aircraft is changed considerably in a short time on the cases like take-off phase and changing of RPM from idle to maximum, because performance of aircraft engine is changed suddenly. This study is aimed to avoid surge in a compressor. Dynamic simulation in a compressor is modeled by simulink in specific condition. Fuel flow is control input, rpm and air mass flow are expressed in terms of transfer function. Surge margin is obtained by using compressor performance map from NPSS. VIGV(Variable Inlet Guide Vane) is controlled by PD controller with difference between surge margin and reference. Finally this paper verifies IGV can prevent surge phenomenon in a compressor.

• The KSFM Journal of Fluid Machinery
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• v.10 no.3 s.42
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• pp.17-24
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• 2007

This paper presents the design procedure of a vertical wind turbine named jet-wheel-turbo turbine and the numerical and experimental verifications. The design parameters such as the rotor inlet angle, the diameter-to-hub ratio, the inlet guide outlet angle and the solidity were optimized to maximize the energy transfer, and to further increase the turbine efficiency by applying the side guide vane and the side opening to the rotor. The maximum power coefficient of 0.59, which is much higher than the ever-designed three-bladed horizontal turbines, was experimentally obtained when the optimal inlet- and side-guide vanes were installed and both sides of the rotor were 80% opened. The maximum power coefficients occur at the tip speed ratio ranging between 0.6 and 0.7. This vertical-axis turbine model can be applied to the large-scale power generation system with the speed and torque control algorithm for the specified wind characteristics.