• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제30회 춘계학술대회논문집
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• pp.5-8
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• 2008

본 연구는 지난 연구에 이어서 핸드피스 터빈 형상에 따른 유동특성 및 성능을 수치해석을 이용하여 연구하였다. 정상상태 방법 중 하나인 프로즌 로터 방식을 이용하여 노즐 중심선과 터빈 로터사이의 여러 각도에 따라 계산하였다. 평평한 모양, 오목한 형상, 갈매기 모양 등 3가지 터빈 로터 형상의 특성을 분석하였다. 추가적으로, 가장 성능이 좋은 로터 모양에 있어서 다른 반사각으로 계산을 하였다.

• 한국해양공학회지
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• 제14권3호
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• pp.84-89
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• 2000

The purpose of this study is to investigate the combustion emission characteristics by the effect of secondary air injection and variation of the excess air ratio in combustion field of model gas turbine combustor. For this purpose, mean temperature, CO, $CO_2$, $O_2$ and HC concentrations were measured by changing excess air ratio and secondary air injection. As a result of this study, mean temperature was decreased and CO, HC emission increased by increasing the excess air ratio of secondary air. Therefore, this results showed the secondary air injection effected strongly on the flame structure and combustion emission characteristics.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 춘계학술대회 논문집
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• pp.171-176
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• 2000

This purpose of this study is to investigate the combustion emission characteristics on the effect of secondary air injection in combustion field of model gas turbine combustor changing excess air ratio. For this purpose, meantemperature, CO, CO2, O2 and HC concentration were measured by changing excess air ratio and secondary air injection. As a result of this study, meantemperature, CO2 emission was decreased and CO emission increased by increasing the excess air ratio of secondary air. therefore, This paper showed the effect of Secondary air injection on flame structure, combustion emission characteristics.

• Journal of Chest Surgery
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• 제24권12호
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• pp.1225-1227
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• 1991

Pneumomediastinum and subcutaneous emphysema produced by air turbine dental drills, although widely reported in dental publications, are rarely reported in the thoracic journals. We report a case of 38-year-old man with pneumomediastinum and subcutaneous emphysema after use of a air turbine dental drill for dental extraction.

• 한국유체기계학회 논문집
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• 제18권4호
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• pp.49-55
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• 2015

The pumped storage plant operates with quick change of the discharge as well as quick changes between pump mode and turbine mode. This study focuses on the cavitation analysis of a pump-turbine model because in turbo-machinery, cavitation can reduce the performance and shorten service life. The pump-turbine model system consists of 7 blades, 20 stay vanes (including tongue) and 20 guide vanes. This study adopts the Rayleigh-Plesset model as a cavitation model, which illustrates cavitation by using the air volume fraction method. The pump mode and turbine mode at the operating condition of partial loading, normal and excessive loading are analyzed to investigate the cavitation performance of the pump-turbine. It was observed that this pump-turbine design showed very good cavitation characteristics with no cavitation bubbles in all operating conditions. Overall value of air volume fraction of both mode at different operating condition are lower than 1, which confirms low possibility of cavitation occurrence at current situation.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 1998년도 유체기계 연구개발 발표회 논문집
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• pp.209-214
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• 1998

A thermodynamic simulation method is developed for the process design and the performance evaluation of the gas turbine in IGCC power plant. The present study adopts four clean coal gases derived from four different coal gasification and gas clean-up processes as IGCC gas turbine fuel, and considers the integration design condition of the gas turbine with ASU(Air Separation Unit). In addition, the present simulation method includes compressor performance map and expander choking models for considering the off-design effects due to coal gas firing and ASU integration. The present prediction results show that the efficiency and the net power of the IGCC gas turbines are seperior to those of the natural gas fired one but they are decreased with the air extraction from gas turbine to ASU. The operation point of the IGCC gas turbine compressor is shifted to the higher pressure ratio condition far from the design point by reducing the air extraction ratio. The exhaust gas of the IGCC gas turbine has more abundant wast heat for the heat recovery steam generator than that of the natural gas fired gas turbine.

• 한국추진공학회지
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• 제5권2호
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• pp.65-72
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• 2001

본 연구에서 MAT(Moisture Air Turbine) 사이클은 압축기 입구에 미세한 액적을 분무함에 따라, 가스터빈 엔진의 성능을 향상시킬 수 있음을 제시하였다. 혼합물이 상변화하는 동안의 압축기 일은 이론적으로 등 엔트로피 압축 일로 고려하였다. 상변화 과정에서 증발잠열의 영향으로 압축기 일은 감소함을 알 수 있다. 성능해석 프로그램을 이용해서 1000, 1210, 1350 rps 조건에서, 압축기 유입공 기에 대한 1.0%의 물을 분무했을 경우, 각각 16.2%, 14.9%, 12.6%의 출력이 증가함을 확인하였다. 또한 압축기 일의 감소에 의해 열 효율도 증가함을 확인하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2001년도 제16회 학술발표회 논문초록집
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• pp.54-58
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• 2001

본 연구에서는 MAT(Moisture Air Turbine) 사이클이 압축기 입구에 미세한 물방울을 분무함에 따라, 가스터빈 엔진의 성능을 향상시킬 수 있음을 제시하였다. 혼합물이 상변화하는 동안의 압축기 일은 이론적으로 등 엔트로피 압축 일로 고려하였다. 여기서 습증발의 영향을 고려함에 따라 압축기 일이 감소함을 알 수 있었다. 성능해석 프로그램을 이용해서 1000, 1210, 1350 rps 조건에서, 압축기 유입공기에 대한 1.5% 의 물 분무시 사이클 모델 계산을 이용해서 각각 21.7%, 20.2%, 18.4%의 출력이 증가함을 확인하였다. 또한 효율도 압축기 일의 감소에 의해 개선되어짐을 확인하였다.

• 한국정밀공학회지
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• 제28권1호
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• pp.80-88
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• 2011

The dental high-speed air turbine handpiece is one of the most popular devices that have been widely used as the main means of cutting tooth structure and restorative material in dentistry. In consideration of usage and marketability of the dental handpiece, it is obviously worthy of investigating it. The goal of this paper is to establish the relationship between the air turbine speed and the supply route inside the handpiece. To do this, the Computational Fluid Dynamics(CFD) tool, Fine$^{TM}$/Turbo is used and the optimal supply route position is suggested from the simulation results. In addition, as an attempt for domestic product, the reverse engineering process of a high speed dental handpiece by 3D X-Ray CT equipment and wire cutting is presented for the Mark II model in NSK. In doing so, the 3D modeling of the handpiece parts is carried out with CATIA V5, and the interference between parts is examined. Finally, the result of performance test for the prototype produced in this research is presented.

• 소음진동
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• 제8권6호
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• pp.1062-1068
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• 1998

This paper describes the vibration characteristics of a high head pump-turbine runner. with nine blades and an outer diameter of 4.410 mm. of the pumped storage power plant. Mode shapes and natural frequencies were obtained by means of both the finite element analysis and modal testing. both in air and in water. The natural frequencies in air were calculated using the finite element method by ANSYS software. In order to confirm calculation results. the natural frequencies and mode shapes of the runner were measured using a hydraulic exciter both in air and in water. Natural frequencies of the pump-turbine runner were found at 174. 310 Hz in air, and at 107. 184 Hz in water. The first mode shape is flat plate mode with two nodal diameter and the second one is also flat plate mode with three nodal diameter. It can be shown that the natural frequencies of the pump-turbine runner in water is reduced approximately 40 ％ due to additional mass effect. Natural frequencies in air predicted by ANSYS software are in good agreement with test results.