• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 하계학술발표대회
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• pp.223-223
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• 2005

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 추계학술대회
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• pp.536-538
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• 2015

전기 에너지가 우리 생활에 유용하게 사용되는 부분이 정말 많다. 최근에는 자전거 열풍이 불면서 덩달아 전동 자전거 업계에도 호황이 일고 있는데, 21C 기후 변화와 환경오염, 교통체증 등의 문제해결을 위한 저탄소 녹색성장의 인식 전환으로 전동 자전거 이용이 늘어나고 있다. 이는 전동 자전거도 전기 에너지가 사용되고 있다 점이다. 하지만 이런 장점을 가지고 있는 전동 자전거를 많은 사람들이 구입하지 못하는 이유가 있다. 대부분의 이유가 '집에 자전거 1대씩 가지고 있는데, 굳이 비싼 돈을 주고 전동 자전거를 구입해야하나?' 라는 생각을 가지게 된다. 또 다른 이유로는 기존의 전동 자전거가 탈 부착 형식이 아닌 일체형으로 나오기 때문에 다른 신제품의 전동 자전거가 나온다면 기존의 전동 자전거의 부품을 사용하지 못 하고 새로운 자전거를 사야 한다는 단점 때문이다. 따라서 본 논문에서는 탈 부착이 가능한 전기 자전거 시스템을 구현하고자 한다.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 1999년도 유체기계 연구개발 발표회 논문집
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• pp.134-140
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• 1999

A three-dimensional CSCM upwind flux difference splitting Navier-stokes code with two-equation turbulence models was developed to predict the transonic flows in centrifugal compressor diffuser. The k-$\epsilon$ model of Abe et al. performed well in predicting the pressure distribution in the shock wave/turbulent boundary-layer interaction. Three turbulence models predicted the similar distribution of static pressure through the diffuser and showed a good agreement with the experimental results. The secondary flows in the corner were predicted well by these turbulence models. The pressure increase before the throat of the diffuser vane is important for the overall pressure recovery. As the mass flow rate increased the blockage decreased at the throat. The pressure coefficient distribution through the diffuser depended on the throat blockage not on the rotational speed of the impeller.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.649-654
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• 2001

This paper describes aerodynamic preliminary design performance prediction and flow analysis for centrifugal compressor of the marine middle engine turbocharger. The performance characteristics of turbocharger compressor are investigated at various operating conditions using mass flow rate and revolution speed, and computational flow analysis for impeller and diffuser at design point are performed. Preliminary design results correspond to actual compressor geometric values comparatively by applying modified slip factor. Performance prediction and flow analysis results show good agreement with experiments. Therefore, this will provide the performance prediction in preliminary design, and help to increase the design capability for optimized impeller.

• 한국유체기계학회 논문집
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• 제18권4호
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• pp.22-29
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• 2015

In this study, an in-house program to predict steady state operation of micro gas turbines is constructed using MATLAB. The program consists of two parts: design and off-design simulations. The program is fully modular in its structure, and performance of each component (compressor, combustor, turbine, recuperative heat exchanger and pipe elements) is calculated in a separate calculation module using mass and energy balances as well as models for off-design characteristics. The off-design modules of compressor and turbine use performance maps, which are program inputs. The off-design operation of a micro gas turbine under development was predicted by the program. The prediction results were compared with those by commercial software, and the validity of the in-house program was confirmed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1092-1097
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• 2004

The heat (mass) transfer characteristics on the endwall surface of a first-stage linear turbine rotor cascade at off-design conditions has been investigated by employing the naphthalene sublimation technique. The experiments are carried out at the Reynolds number of $2.78{\times}10^{5}$ for two incidence angles of -5% and +5%. The positive incidence angle results in intensification of the pressure-side leg of a leading-edge horseshoe vortex, which delivers higher heat transfer along its trace. On the other hand, the negative incidence angle show an opposite tendency.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.658-663
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• 2001

In this study, the axial-compressor design and performance/flow analysis program is developed. A mean-line analysis was used to determine optimum arrangement of overall geometry and its off-design performance is predicted by stage-stacking method. Three dimensional blade shape is generated using radial equilibrium equation and vortex methods. Various blade shape is generated and their performance is compared. Finally the quasi-three dimensional flow analysis is applied to investigate the detailed flow phenomena.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.670-675
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• 2001

This paper describes aerodynamic preliminary design performance prediction and flow analysis for turbine of the marine middle engine turbocharger. The performance characteristics of turbocharger turbine are investigated at various operating conditions using mass flow rate and computational flow analysis for rotor and nozzle at design point are performed. Preliminary design results are performed by applying mean line and radial equilibrium theory. Performance prediction and flow analysis results show good agreement with experiments. From 3 dimensional flow analysis result, efficiency is 0.6% greater than design point. Therefore, this design approach is useful for preliminary design, and helps to increase the design capability for optimized rotor blade.

• 대한기계학회논문집
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• 제17권7호
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• pp.1851-1863
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• 1993

A procedure for the prediction of the off-design performance of a gas turbine engine is proposed. The system performance at off-design speed is predicted by coupling the thermodynamic models of a compressor and a turbine. The off-design performance of a compressor is obtained using the stage-stackimg method, while the Ainlay-Mathieson method is used for a turbine. The procedure is applied to a single-shaft gas turbine and its predictability is found satisfactory. The results also show that the net work output increases with the increase of the turbine inlet temperature, while the thermal efficiency is marginal. The maximum thermal efficiency at design point is obtained between the highest pressure ratio and design pressure ratio.

• 대한기계학회논문집B
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• 제24권8호
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• pp.1077-1084
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• 2000

In this work, a modified stage-stacking method for the performance prediction of multi-stage axial flow compressors is proposed. The method is based on a simultaneous calculation of all interstage variables (temperature, pressure, flow velocity) instead of the conventional sequential stage-by-stage scheme. The method is also very useful in simulating the effect of changing angles of the inlet guide vane and stator vanes on the compressor operating characteristics. Generalized stage performance curves are used in presenting the performance characteristics of each stage. General assumptions enable determination of flow path data and stage design performance. Performance of various real compressors is predicted and comparison between prediction and field data validates the usefulness of the present method.