• The KSFM Journal of Fluid Machinery
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• v.7 no.4 s.25
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• pp.16-23
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• 2004

Hydraulic performance and cavitation characteristics of fuel pump in turbopump were studied experimentally. This fuel pump has a centrifugal impeller with a separate inducer. In this paper, static pressure distribution of inducer was examined in non-cavitation and cavitation conditions. As cavitation came, the rising curve of static pressure in front of inducer was lightened because blade lodging did. In result, this offered the mechanism that recirculation zone could be small in case that recirculation was generated in low flow rate.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.445-451
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• 2004

Four design candidates for a 1.4MW class partial admission turbine have been chosen from a Preliminary design process. Their performance were estimated through the 3-D numerical analyses using a frozen rotor method. In order to select the optimum design, each flow analysis result was compared with others. Flow characteristics in the passages and some types of losses induced by shocks and wakes were found from calculation results. Based on these calculations, a new rotor blade was redesigned and compared with previous one through flow analysis.

• The KSFM Journal of Fluid Machinery
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• v.7 no.6 s.27
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• pp.15-20
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• 2004

Numerical analysis of the partial admission turbine in the KARI turbopump has been performed. Flow field of the partial admission turbine is intrinsically unsteady and three dimensional. To avoid heavy computational efforts, the frozen rotor method is adopted in computation and compared with the mixing plane approach. The frozen rotor method can represent the variation of a flow field along the circumferential direction of rotor blades, which have the different relative positions to the nozzle with one another. It also illustrates the wake loss mechanism starting from the lip of a nozzle, which is not captured in the mixing plane method. The frozen rotor method has proven to be an efficient tool for the design of a partial admission turbine.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.43-48
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• 2004

A screw-type centrifugal pump was manufactured to carry solids primarily and its impeller has a wide flow passage. However, the effect of flow passage shape on delay of the choke due to entrained air has not been clarified yet. Moreover, because its impeller has a particular shape, only few studies have tried to clarify the pump performance and details of internal flow pattern of that pump. For that reason, we carried out the pump performance experiment under air-water two-phase flow condition with different impeller tip clearances, pump rotational speeds and void fractions by using a small screw-type centrifugal pump designed to acquire basic data. In a general centrifugal pump, it was reported that loss of pump head from single-phase flow to the choke due to air entrainment new the best efficiency point was large. However, the loss near the best efficient point in a screw-type centrifugal pump became less than that in a general centrifugal pump.

• Journal of the KSME
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• v.30 no.6
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• pp.542-547
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• 1990

가스터빈은 브레이턴사이클을 이용한 것으로서 피스톤 왕복엔진과 함께 동력기관으로써 지금까지 사용되고 있으며 특히 경량, 고출력의 장점으로 인해 항공기 엔진의 추진기로서 많이 사용되고 있다. 1905년 프랑스에서 압축비 4.8회전수 4250rpm으로 40HP의 출력을 내는 현재와 같은 형 태의 가스 터빈을 개발한 이후 많은 발달과 함께 2차 대전 후에는 항공용 뿐만 아니라 발전용, 동력용 등 산업용 엔진에도 응용되었다. 세계적으로는 유럽이 가스 터빈에 관한 연구를 미국보 다 앞서 활발히 진행하였으며 1957년 General Electric사의 F-4팬텀에 사용된 J-79터보 제트 엔진을 개발함으로써 가스터빈 엔진분야에 미국이 주도권을 잡게 되었고 많은 전문회사가 가스 터빈 엔진설계 제작에 참여하고 있다. 이와 같이 가스 터빈에 대한 개발연구가 계속 이루어진 것은 가스 터빈이 다른 동력기관 보다 단위 중량당 많은 출력을 낼 수 있고, 각 요소들이 회전 운동을 함으로써 고속운전을 할 수 있고, 부하 변동에 빨리 적응하며, 마찰부분이 적어 윤활유 소비가 적은 장점들이 있기 때문이다. 본 글에서는 이와 같은 가스 터빈 연구개발의 국내외 현황 및 그 전망에 대해서 기술하고자 한다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.3
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• pp.664-675
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• 1990

In this study, the performance test and heat transfer experiment for a 4 cylinder and 4-cycle turbocharged gasoline engine were carried out in order to measure the heat transfer coefficient at the inner wall of the combustion chamber. From the result of heat transfer experiment, the energy balance of the fuel energy and the overall efficiency of the turbocharger were calculated, The variation of them was investigated as well with the engine operation conditions.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.2
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• pp.26-31
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• 2011

This article provides the systematic design methodology for a tilting pad journal bearing. First the dynamic factors for the bearing are selected with the critical speed analysis. The pad bearing is then designed to have its best mechanical efficiency by simulations with changing of the number of pad and the lubricant flow rate with meeting the design specifications such as metal temperature, clearance and so on. And the simulation results are reviewed to compare with an experimental test. Finally the stability of rotor with the designed bearing is investigated. This methodology is successfully applied to the rotor for 1.2MW turbo-blower.

• The KSFM Journal of Fluid Machinery
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• v.7 no.5 s.26
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• pp.43-49
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• 2004

A turbo blower, driven by a high-speed blushless DC motor, was designed as a efficient substitute of a ring blower or a roots blower. Computational analysis and performance tests have been performed to investigate performance characteristics of the blower. Experimental measurements showed that the blower has a good stability margin. This paper gives an outline of design, computational flow analysis and performance test for aerodynamic evaluation of the variable speed turboblower.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.469-475
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• 2003

The performance of a centrifugal compressor composed of an impeller, tandem diffuser rows and axial guide vanes has been predicted numerically and compared with available experimental results on its design rotational speed. The pitchwise-averaged mixing plane method was employed for the boundaries between rotor and stator to obtain steady state solutions. The overall characteristics showed differently according to the relative positions of tandem diffuser rows while the characteristics of impeller showed almost identical. The numerical results agree with the measured data in respect of their tendency. It turned out that 0% of relative positions is the worst case in terms of static pressure recovery and efficiency. According to the experimental results, some pressure fluctuations and malfunction of the compressor were observed for 75% case. However, this numerical calculation using mixing plane method did not capture any of those phenomena. Thus, unsteady flow calculation should be performed to investigate the stability of the compressor caused by different diffuser configuration.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.4
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• pp.739-752
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• 1989

The temperature distribution and heat flux of the inner wall of the cylinder of turbocharged gasoline engine were calculated by the 3-dimensional heat conduction analysis employing boundary element method. Overall mean effective heat transfer coefficient and thermal resistance ratio and equivalent thickness of the cylinder wall were calculated. the numerical results were discussed with respect to the engine speed, equivalence ratio, spark and boost pressure.