• 한국유체기계학회 논문집
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• 제11권1호
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• pp.33-39
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• 2008

Hybrid power generation systems combining a solid oxide fuel cell and a gas turbine is promising due to their high efficiency. In the pressurized hybrid system, the operating condition of the gas turbine may play a critical role in designing the hybrid system. In particular, prevention of surge of the compressor can be a critical issue. The existence of fuel cell between the compressor and the turbine may cause an additional pressure loss and thus compressor operating points tend to approach the surge if the original turbine inlet temperature is pursued. In this study, bypassing some of the turbine inlet gas directly to the turbine exit side is simulated. Its effects on suppressing the surge problem and change in performance characteristics are discussed.

• International Journal of Fluid Machinery and Systems
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• 제6권4호
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• pp.189-199
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• 2013

A practical method of surge simulation in a system of a high-pressure-ratio multistage axial flow compressor and ducts, named SRGTRAN, is described about the principal procedures and the details. The code is constructed on the basis of one-dimensional stage-by-stage modeling and application of fundamental equations of mass, momentum, and energy. An example of analytical result on surge behaviors is included as an experimental verification. It will enable to examine the transient flow phenomena caused by possible compressor surges and their influences on the system components in plant systems including high-pressure-ratio axial compressors or gas turbines.

• 한국소음진동공학회논문집
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• 제20권5호
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• pp.502-509
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• 2010

A test facility which can simultaneously measure turbocharger operating condition variables and vibro-acoustic emission in the situations that are quite similar to real internal combustion engine operating conditions has been introduced. Using this facility, a new method sweeping from full open throttle to deep surge region along constant speed curves can be utilized instead of the stationary method that has been traditionally used to obtain turbocharger compressor maps. Data covering an extensive range of the compressor performance map have been collected and analyzed. An experimental study is performed to define a noise diagram that correlates vibro-acoustic measurements to aerothermodynamic operating conditions. An instrumentation set in the facility allows the automatic definition of the operating point on the turbine and compressor map of the turbocharger. Also, radiated sound pressure and casing vibration data corresponding to the point are obtained by a microphone in the vicinity of the compressor casing and an accelerometer on the casing. The major source(s) of noise at specific operating point on the map can be easily identified with these maps. Also, acoustic characteristics of a given turbocharger at the vicinity of the surge as well as in the surge are also defined. Finally, the possibility to define mild surge region of a turbocharger using vibro-acoustic measurements is studied.

• 대한기계학회논문집B
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• 제40권5호
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• pp.297-304
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• 2016

통상 제어기 설계용으로 개발되는 차량용 수퍼 차져의 동적 거동 모델은 경험식에 의존한 압축기 맵을 활용하고 있어, 실제 서지 현상의 발생에 따른 시스템의 영향과 거동특성을 모사하는데 한계가 있다. 본 연구에서는 수퍼 차져의 운전 동특성을 모사할 수 있는 해석기반 압축기 모델을 개발하고 운전 변동성에 따른 압축기의 운전 추이를 모사하고자 한다. 모델 개발은 SIMULINK$^{(R)}$ 환경에서 진행하고, 기준 동특성 모델은 Greitzer의 압축기 모델을 적용하였다. 해석 결과는 실험 결과와 비교 검증을 통해 모델의 타당성을 확인하였으며 운전 특성 변화에 따른 압축기 성능 및 서지 발생 가능성에 대해 확인 하였다.

• 한국유체기계학회 논문집
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• 제15권2호
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• pp.12-19
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• 2012

This study presents unsteady and unstable characteristics of three stage transonic axial compressor, developed by Korea Aerospace Research Institute. As approaching to the unstable operating region at the 103% design speed of the compressor, a modal type stall precursor appears in front of highly loaded 3rd rotor row at first, and it propagates to the upstream. On the contrary, actual stall cell initiates from the stall precursor in front of the 1st rotor row, and it propagates to the downstream of the compressor. After the stall region reached the 3rd stage and stall cell rotates circumferentially about 360 deg, it develops to one dimensional compressor surge mode. It shows a mild surge behaviour with 3~4 Hz frequency. From the test data, it can be suggested that there is a priority to give an optimum blade loading distributions to construct a multi stage transonic axial compressor stages either to secure more stable compressor operating ranges, or to maximize the compressor efficiency.

• 한국유체기계학회 논문집
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• 제5권3호
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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.

• Journal of Advanced Marine Engineering and Technology
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• 제35권4호
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• pp.443-450
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• 2011

연료가스 압축 시스템은 중급의 FPSO에 설치되며, 이 시스템에서 서지를 방지하기 위하여 안티 서지 밸브가 사용되어진다. 만약 서지가 발생하게 되면 시스템의 파괴를 초래할 수 있으므로 안티서지 밸브는 반드시 구조강도와 구조안전성 평가가 수반되어야한다. 특히, 비상시에도 밸브는 구조안전성과 그 성능을 보장해야 된다. 이 연구에서는 안티서지 밸브의 구조강도와 구조안정성 평가를 수치해석을 통하여 수행하였다. 형상모델은 유니그래픽스 NX4.0을 사용하였으며 시뮬레이션은 ANSYS Workbench 12.1 버전을 이용하였다. 밸브의 허용 강도와 안전계수는 ASME Boiler & Pressure Vessel Code를 참조하였다.

• International Journal of Fluid Machinery and Systems
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• 제2권4호
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• pp.409-417
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• 2009

An investigation of surge inception in a centrifugal compressor was done with measurements of steady and unsteady static pressure. Vaneless diffuser and vaned diffuser were tested. Analyses of the static pressure and the pressure fluctuation showed that stall at the impeller leading edge occurred at first, and then it extended to downstream. In case of the vaneless diffuser, deterioration of the pressure rise in the impeller triggered instability. For the vande diffuser, instability that was generated in the impeller propagated into the vaned diffuser, however the pressure recovery by the vaned diffuser made the operation of the compressor stable at low flow rate.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.181.2-181.2
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• 2005

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.1291-1292
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• 2011