• Title/Summary/Keyword: 흡입 유체

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A Parametric Study for the Design of Flush inlet (Flush 흡입관 설계를 위한 매개변수 연구)

  • Lee J. G.;Jung S. Y.;Ahn C. S.
    • 한국전산유체공학회:학술대회논문집
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    • 2004.03a
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    • pp.132-138
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    • 2004
  • Flush inlet, which has been chosen for modem air vehicles to take advantage of structure compactness and small RCS, gives rise to some aerodynamic problems such as flow separation and distortion due to vortices which deteriorate the performance of both inlet and engine. In this study, pressure recoveries at inlet exit plane were evaluated through numerical analyses of 3D turbulent flow for various inlet shapes and flight conditions. Inlet shape was controlled by changing ramp angle and width of throat, and effects of mass flow rate and angle of attack were investigated.

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Numerical Simulation of Suction Performance of a Forward-Sweep Inducer for Turbopumps (터보펌프용 전진익형 인듀서 흡입성능 유동해석)

  • Choi, Chang-Ho;Noh, Jun-Gu;Kim, Jinhan
    • The KSFM Journal of Fluid Machinery
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    • v.17 no.3
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    • pp.13-18
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    • 2014
  • Computational and experimental studies on a forward-sweep inducer for turbopumps were performed to see the effect of the blade sweep on the suction performance of the inducer. Computational results show that backflows at the inlet decrease in the case of the forward-sweep inducer by inhibiting pre-rotation of the inflow and the low pressure region near the tip also diminishes, which is presumed to improve the suction performance of the inducer. The predicted suction performance of the inducer is compared with the experimental result. The result shows that the computation overestimates the suction performance of the inducer compared to the value from the experiment.

Drag reduction in channel flow using stationary distributed blowing and suction (고정된 분포 분사/흡입을 통한 채널 유동의 저항 감소)

  • Kim, Joo-Hyun;Choi, Hae-Cheon
    • 유체기계공업학회:학술대회논문집
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    • 2006.08a
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    • pp.195-198
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    • 2006
  • The possibility of skin friction reduction in laminar channel flow is investigated when the flow is subjected to stationary distributed surface blowing and suction. Blowing and suction provided at the channel walls is steady in time but varies as a sine function along the streamwise direction. The skin friction changes depending on the wavelength and amplitude of the actuation. Especially, the skin friction is reduced below that of fully developed laminar flow as the wavelength decreases and amplitude increases. The optimal wavelength of producing minimum skin friction is $\pi/2{\delta}$, where $\delta$ is the channel half-height It is observed that the distributed blowing and suction induces strong negative Reynolds shear stress in the near-wall region at the end of the suction part.

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A Study on the Leading/Unloading Time Prediction of the Ballast Tank (밸러스트 탱크의 급수/배수 시간 예측에 관한 연구)

  • Kim H. I.;Kim M. U.;Choi D. H.
    • 한국전산유체공학회:학술대회논문집
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    • 2004.10a
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    • pp.33-36
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    • 2004
  • The ballast tank of a ship is a system that realizes the required shipping condition and controls the draft of a ship. The loading/unloading of the ballast tank is frequently operated during navigation and the accurate prediction of the loading/unloading time is very important. A numerical algorithm that predicts the loading/unloading time of the ballast tank has been developed and applied to the prediction of the loading/unloading time of the ballast tank with various piping systems. This algorithm can be useful in optimizing the ballast tank system in early design stage.

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Numerical Analysis of Flow Characteristics around 3D Supersonic Inlet at Various Angle of Attack (받음각이 있는 3차원 초음속 흡입구 주위의 유동진동 해석)

  • Kim, J.;Hong, W.;Kim, C.
    • 한국전산유체공학회:학술대회논문집
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    • 2011.05a
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    • pp.218-224
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    • 2011
  • A supersonic inlet at angle of attack has anti-symmetric pressure distribution, and it can make flow instability and structural problem. In this study, numerical analysis of three-dimensional inviscid flow was conducted under various throttle ratio and angle of attack conditions. Throttle ratio was defined as the ratio of the exit area to the smallest cross section area at inlet, and the ratio is controlled from 0 to 2.42. At various angle of attack, the characteristics of steady and unsteady flow around supersonic inlet is observed under different throttling ratios. From these results, pressure recovery curves and pressure history curves were plotted by post processing. Using pressure history data, FFT analysis is also carried out. Through these processes, it shows the tendency of pressure distribution anti-symmetricity and changing dominant frequency as increasing angle of attack.

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Effects of Inducer Tip Clearance on the Suction Performance of a Pump for Turbopumps (인듀서 익단간극이 터보펌프용 펌프의 흡입성능에 미치는 영향)

  • Choi, Chang-Ho;Kim, Dae-Jin;Kim, Jin-Han
    • The KSFM Journal of Fluid Machinery
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    • v.15 no.1
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    • pp.41-45
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    • 2012
  • The effects of inducer tip clearance on the suction performance of a pump for turbopumps are investigated. Experiments for the pump with inducer tip clearances of 1.8% and 1.4% of blade height were performed. The experimental results showed that the suction performance of the pump increased as the tip clearance decreased. It seems that the suction performance of the pump becomes better with smaller tip clearances because the strength of the inducer backflow becomes weak with the decreased tip clearance.

Put Effect of the inducer scale on the suction performance similarity of a turbopump (인듀서의 크기가 터보펌프의 흡입성능 상사에 미치는 영향에 관한 연구)

  • Kang, Byung Yun;Kang, Shin-Hyoung
    • The KSFM Journal of Fluid Machinery
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    • v.17 no.4
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    • pp.47-52
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    • 2014
  • An inducer is forward-attached to an impeller to improve the suction performance. This paper described the experimental and numerical investigations on the concept of NPSH similarity about the inducer scale. As Reynolds number decreased for the same scale inducer, the hydraulic performance is slightly reduced because of the viscosity. The suction performance similarity is in good agreement. For different scale inducers, the NPSH similarity did not follow the conventional rule which is proportional to the square of the inducer diameter. A cavity of two times scale inducer grows faster under cavitation inception, and the head is more drop as the fluid passes blades. Because of the simplified cavitation model and vapor pressure, the NPSH similarity dose not have an accuracy. This study suggested an empirical formula for the NPSH similarity.

Fluid-Structure Interaction Analysis of Pressure Pulsation in a Suction Pipe of Compressor (압축기 흡입배관 압력 맥동의 유체-구조 연성 해석)

  • Oh, Han-eum;Jeong, Weui-Bong;Ahn, Se-Jin;Kim, Min-sung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.779-780
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    • 2014
  • This paper dealt with numerical estimation of pressure pulsation of the refrigerant in a suction pipe of the compressor. To evaluate the effect of reduction of pressure pulsation, a pipe system with tube was simulated using F.S.I.(Fluid-structure interaction) analysis. A commercial program was used for calculating behavior of pressure. The numerical simulation for pressure ratio of before and after going though internal structure were carried out. As a result, it was verified that the pressure after passing structure is less than the pressure before passing internal structure depending on the longitudinal frequency of structure.

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Numerical Flow Analysis of a Partial Admission Turbine Using a Frozen Rotor Method (프로즌 로터 기법을 이용한 부분흡입형 터빈 수치해석)

  • Noh, Jun-Gu;Jeong, Eun-Hwan;Lee, Eui-Seok;Kim, Jin-Han
    • 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.

Flow Analysis of the Rotating Sludge Suction Collector by Numerical Simulation (수치시뮬레이션을 이용한 흡입식 슬러지 수집기의 유동해석)

  • Suh, Sang-Ho;Roh, Hyung-Woon;Byun, Jong-Youn
    • The KSFM Journal of Fluid Machinery
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    • v.9 no.5 s.38
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    • pp.22-27
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    • 2006
  • Sedimentation phenomenon of suspended solids occurs by the gravitational force. Pollution particles are separated from slowly flowing waste water in clarifier. Recently, the sludge suction collector is Preferred rather than the scraper type sludge collector due to the enhancement of the clarifier efficiency. The sludge suction collector is usually operated by the user's experiences without any scientific and/or technical consideration. To evaluate the performance of sludge suction collector, the three dimensional numerical simulation was conducted by the finite volume method. To analyze the performance, the velocity vectors and the suction flow rates of the orifices were investigated. The result showed that each suction flow rate through out the collector was equivalent in the sludge suction collector and the efficiency of suction collector was good to remove high concentrated sludge in clarifier.