• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1438-1439
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• 2015

수질정화를 위하여 여러 가지 방법이 연구되고 있다. 지금까지의 연구결과는 분수대고정 콘크리트 시공에 따른 유동적인 효과의 미흡과 1.2m이상의 높은곳에 위치함으로써 효율저하가 있었으나 본연구는 효율저하를 막고 수중펌프 흡입구와 분수노줄막힘을 방지하기 위하여 0.7m의 높이에 수질정화장치를 설치하고 임펠러 회전체를 개방함으로써 보다 높은 성능을 가진 수질 정화장치용 분수를 만들어 안전도를 증가 시켰다.

• Journal of Energy Engineering
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• v.14 no.2 s.42
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• pp.73-81
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• 2005

An Experimental study was conducted to investigate the effective way for fuel consumption improvement in radiant tube burner heating system used in steel manufacturing process. To find effectiveness of increase of temperature and oxygen fraction of intake air on fuel consumption, the model radiant tube burner heating system with recuperator was designed to be able to adjust temperature and oxygen fraction of intake air, and was operated under various conditions with oxygen concentration in exhaust gas changed. The results show that burner chamber temperature was increased about $10\%$ of intake air temperature increase. so it was difficult to expect fuel consumption improvement. But only 1 or $2\%$ increase of oxygen fraction in intake air made a significant improvement in fuel consumption even though it made much NOx emissions also. Therefore, if NOx emissions is controlled under regulation with burner modification, it is expected that increase of oxygen fraction in Intake air is effective way to improve fuel consumption.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.590-593
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• 2009

To identify the detailed 3D flow characteristics of a model scramjet engine, a unified 3D numerical analysis was performed. The numerical domain of concern includes the entire flow path of the model scramjet engine extending from the intake to the nozzle exhaust. Turbulent models($k-{\omega}$ SST and low Reynolds number k-e with Sarkar model) were applied with comparison of experiment result. Intake side wall's effect on flow characteristics was analyzed in view points of flow quality at inlet duct and near the flame holder as well. The code is paralleled with multi-block feature using MPI(Massage Passing Interface) library to speed up the 3D calculation.

• Aerospace Engineering and Technology
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• v.3 no.2
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• pp.197-207
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• 2004

The developing Smart UAV in KARI supposes high speed flight as like a conventional plane, as well as vertical takeoff and landing as like a helicopter. Therefore, the air intake system should be designed to provide the sufficient air flow to the engine and the maximum possible total pressure recovery at the engine intake screen over a wide range of flight conditions. For this purpose, we designed the intake system using a pitor type intake model and plenum chamber. In this paper, we designed the intake model and analyzed the performance of designed intake system using the general-purpose commercial CFD code, CFD-ACE+. The analysis results of the total pressure variation and the velocity distribution were illustrated in this paper. The pressure recovery and distortion coefficient at a plane coincident with the compressor inlet were calculated and streamline variation through the intake system was investigated at the worst flight condition as well as the standard flight condition.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.3
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• pp.89-95
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• 2015

Performance test was conducted for an oxidizer pump and a fuel pump for a 7 ton class rocket engine, by using water. The pumps were driven by an electric motor. The hydrodynamic performance and the suction performance were measured at flow ratio of the design and off-design conditions. Head-flow curve, efficiency-flow curve, and head-cavitation number curve were obtained. It is confirmed that the pumps can satisfy the design requirements of hydrodynamic performance in terms of the head and the efficiency. The pumps also satisfied the design requirements of suction performance.

• The KSFM Journal of Fluid Machinery
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• v.4 no.4 s.13
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• pp.7-15
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• 2001

Flow analysis was carried out for a double-suction centrifugal pump. Impeller-only models and a full pump model were used to simulate the velocity field and the pressure field of the pump. Heads and efficiencies were calculated with flow rates in order to obtain general performance of the pump. The calculation results were compared to the experimental data, and satisfactory results were obtained. Thus, it may be said that the CFD serves as a useful tool for pump designs.

• Journal of Chest Surgery
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• v.37 no.10
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• pp.884-887
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• 2004

We applied our technique of selective bronchial suctioning (SBS) for the treatment of atelectasis after resection surgery of lung in four patients with refractory atelectasis who were treated successfully. We considered that SBS using hydro-catheter insertion under local anesthesia above fourth tracheal ring is the effective technique for the treatment of refractory atelectasis when conventional respiratory therapy is not effective and a bronchoscopist is not available.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.11
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• pp.909-915
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• 2009

In this paper, a study of performance improvement for a centrifugal vertical pump having specific speed of 330 is introduced. The existing model has high efficiency but needs better NPSH required performance. Such that new pump model is designed to obtain larger suction specific speed. 6 design parameters considered to affect pump performance are selected for impeller design. Key design parameters are investigated using by design of experiments and CFD, and impeller inlet diameter is increased to get better suction performance. The amount of inlet diameter increase is determined by using cavitation analysis. The results show that new design model has higher efficiency and better NPSH required performance than the existing model.

• Journal of the KSME
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• v.23 no.6
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• pp.427-433
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• 1983

내연기관의 성능은 실린더에서 연료의 화학에너지가 열에너지로 얼마만큼 빠르고 완전하게 변화하느냐에 좌우된다. 이를 위해서는 실린더 내에서 뜨거운 압축공기와 연료의 혼합 및 증기화가 요구된다. 엔진의 출력은 매 사이클당 흡입.압축할 수 있는 공기량에 좌우되므로 연소의 해석을 위해서는 실린더 내의 공기유동, 연료의 분무 및 연소과정을 이해 해야한다. 배기와 엔진효율의 요구성때문에 희박 혼합기 또는 EGR (exhaust gas recirculation)이 필요하게 된다. 그러나 희석이 크면 낮은 연소온도, 낮은 층류흐름속도와 화염전면의 낮은 난류강도 때문에 연소기간이 증대하게 된다. 실제로 희박의 증가는 실화 또는 긴 연소 지연기간, 사이클 마다의 연소맥동현상, HC배기의 증가등을 초래하게 된다. 이러한 저온연소의 단점들은 연소상태를 안정시키고 연소량을 증대시키는 공기의 유동을 이용해서 해결 될 수 있다. 최근에는 선회류와 난류의 강도를 증가시켜서 빠른연소(fast burning)를 이루고 있다. 선회류와 난류의 강도를 증대시키는 가장 중요한 2가지 방법은 흡입포트(port), 매니홀드(manifold)설계이다.

• Journal of the korean Society of Automotive Engineers
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• v.15 no.3
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• pp.1-9
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• 1993

디젤 엔진의 연소 과정에서 흡입공기와 분사된 연료의 최적 혼합기 형성이 배기성분, 연료효율 등 엔진의 성능을 향상시키는데 있어 매우 중요한 과제중의 하나이다. 이를 위하여 연료분무 현상에 대한 연구와 더불어 연소실내 공기유동 현상에 대한 연구가 주요 관심대상이 되어왔다. LDV를 이용한 3-D 유속측정 및 각종 CFD Code를 이용한 유동해석등의 방법으로 엔진 실린더 내부의 유동현상을 이해하는데 많은 도움이 되고 있으나 아직도 엔진연소실설계 등 엔진 개발에 있어서는 종래의 방법에 의한 실린더내 와류 강도의 비교평가에 크게 의존하고 있으므로 여기서는 디젤 엔진의 와류를 측정 평가하는 방법으로 Paddle Wheel회전을 이용한 Paddle Wheel식 Swirl Meter방식과 실린더내 흡입공기의 각 운동량을 측정하는 Impulse식 Swirl Meter 방식에 대해 고찰하고자 한다.