• Title/Summary/Keyword: mixing blade

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Simulation of Steady Flow Through Turbine System with Partial Admission Nozzle (부분흡입노즐방식의 터빈시스템에 대한 3차원 유동해석)

  • Hong Chang-Oug;Namkoung Hyuck-Joon;Woo Yoo-Cheol
    • Proceedings of the KSME Conference
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    • 2002.08a
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    • pp.601-602
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    • 2002
  • Numerical simulation using well-known commercial software Fine/Turbo is applied to the analysis of the aerodynamic performance for the supersonic turbine system with partial admission nozzle. Calculation was performed for coupled system of nozzle and blades using mixing plane method. In addition, calculations were also performed for the blades alone to investigate the effect of the performance variation with blade profile. These computational results are compared with the experiments. The agreement between the prediction and the experiment was found to be satisfactory..

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Flow Characteristics about Industrial Agitators Impeller Shape by CFD (전산유체역학을 이용한 산업용교반기의 Impeller형상에 따른 유동특성)

  • Kim, D.K.;Bae, S.T.;Lee, C.J.;Park, J.H.;Kim, O.K.
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2006.06a
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    • pp.321-322
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    • 2006
  • Industrial agitators are used in various industrial fields where they are necessary to intimately mix two reactants in a short period of time. However, despite their widespread use, complex unsteady flow characteristics of industrial agitators are not systematically investigated. The present study alms for clarify unsteady flow characteristics induced by various impellers in a tank. Impellers are pitched blade turbine(PBT) types, Screw type and Rushton turbine type. In this study flow characteristics of the impeller using CFD. The rotating speed of impellers fixed about 100RPM. These three types of Impeller show that typical flow characteristics of axial turbine and suitable for mixing powder

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Numerical Simulation of MIT Flapping Foil Experiment (MIT 요동 익형의 수치해석)

  • Kang, Dong-Jin;Bae, Sang-Soo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.6
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    • pp.777-784
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    • 2000
  • A Navier-Stokes code based on an unstructured finite volume method is used to simulate the MIT flapping foil experiment. A low Reynolds number ${\kappa}-{\varepsilon}$ turbulence model is used to close the Reynolds averaged Navier-Stokes equations. Computations are carried out for the whole experimental domain involving two flapping foils and a downstream hydrofoil. The computational domain is meshed with unstructured quadrilateral elements, partly structured. Numerical solutions show good agreement with experiment. The first harmonics of the velocity in the boundary layer shows local peak value inside the boundary layer and also local minimum near the edge of boundary layer. It is intensified as it develops along the blade surface. This is shown to be caused as the unsteadiness inside the boundary layer is being convected at a speed less than the free stream value. It is also shown that there is negligible mixing of the unsteadiness between the boundary layer and the free stream.

A Numerical Study of Unsteady Wake Flow Characteristics in a Torque Converter (토크 컨버터 내부의 비정상 후류 유동특성에 대한 수치해석 연구)

  • Won, Chan-Shik;Hur, Nahmkeon
    • 유체기계공업학회:학술대회논문집
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    • 2004.12a
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    • pp.705-710
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    • 2004
  • In the present study, a transient incompressible viscous turbulent flow is simulated for the automotive torque converter with moving mesh technique. For the analysis, entire torque converter flow passages are modeled. Computed torque ratio, capacity factor and efficiency show a good agreement with the experiment data. The flow instabilities characterized by back-flow and wake etc. appeared in some cascade passages are shown to be Propagating along tangential direction. These flow patterns are mainly influenced by the pump and turbine blade passing and can't be predicted through conventional steady simulation with a mixing plane approach. The understanding of the unsteady flow characteristics in a torque converter achieved in the present study may lead to the optimal design of a torque converter.

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A Numerical Study of Unsteady Wake Flow Characteristics in a Torque Converter (토크 컨버터 내부의 비정상 후류 유동특성에 대한 수치해석 연구)

  • Won, Chan-Shik;Hur, Nahm-Keon
    • The KSFM Journal of Fluid Machinery
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    • v.9 no.5 s.38
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    • pp.36-41
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    • 2006
  • In the present study, a transient incompressible viscous turbulent flow is simulated for the automotive torque converter with moving mesh technique. For the analysis, entire torque converter flow passages are modeled. Computed torque ratio, capacity factor and efficiency show a good agreement with the experiment data. The flow instabilities characterized by back-flow and wake etc. appeared in some cascade passages are shown to be propagating along tangential direction. These flow patterns are mainly influenced by the pump and turbine blade passing and can't be predicted through conventional steady simulation with a mixing plane approach. The understanding of the unsteady flow characteristics in a torque converter achieved in the present study may lead to the optimal design of a torque converter.

The effect of sintering condition and composition on the mechanical properties of bond materials for micro-blades (Micro Blade용 Bond재료의 소결조건과 조성이 기계적 특성에 미치는 영향)

  • Kim, Song-Hee;Moon, Jong-Chul
    • Journal of Industrial Technology
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    • v.27 no.B
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    • pp.137-144
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    • 2007
  • Sintering condition and various chemical composition of bond materials for micro-blades were studied. The methods mixing of pure powders and using pre-alloyed powders for compaction and sintering were compared and optimized in terms of the evaluation of bending strength and fractographic study. The effect of the amount of graphite as a lubricant and diamond abrasive on the strength of sintered bond materials and fracture toughness was investigated. The strength decreased with increasing the amount of graphite and diamond abrasive.

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Study on the Industrial Agitator's Impeller Shape Analysis Using CFD and Reverse Engineering (CFD와 역설계를 이용한 교반기 Impeller 형상 해석에 관한 연구)

  • Kim, D.K.;Bae, S.T.;Park, J.H.
    • Korean Journal of Computational Design and Engineering
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    • v.11 no.5
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    • pp.359-364
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    • 2006
  • Industrial Agitators are used in various industrial fields where they are necessary to intimately mix two reactants in a short period of time. However, despite their widespread use, complex unsteady flow characteristics of industrial mixers are not systematically investigated. The present study aims for clarify unsteady flow characteristics induced by various impellers in agitator's tank. Impellers are Pitched blade turbine(PBT) types, Screw type and Rushton turbine type(RUT). In this study is numerical analysis of the Industrial agitator's Impeller types. The rotating speed of impellers fixed about 100RPM. Numerical analysis results show that differential flow characteristics of each type Impeller and Rushton turbine type(RUT) is suitable for mixing powder.

Oxygen Transfer in Animal Cell Culture by Using a Silicone Tube as an Oxygenator (실리콘 튜브를 이용한 동물세포 배양장치의 산소전달)

  • 정흥채;김정회
    • Microbiology and Biotechnology Letters
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    • v.20 no.4
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    • pp.445-450
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    • 1992
  • An enhancement of the oxygen transfer rate in a 1$\ell$ bioreactor for mammalian cell culture by using a silicone rubber tubing as an oxygenator was investigated. When the silicone membrane was used to supply oxygen to the culture broth, the oxygen transfer coefficients ($k_{\iota}a$) measured in deionized-distilled water were markedly increased. Effect of surface aeration without the tubing aeration was very low under $1.0hr^{-1}$ of $k_{\iota}a$. The enhancing effects of agitation rates on $k_{\iota}a$ were much more effective than those of aeration rates. The increase of $k_{\iota}a$ with increasing tube length was observed as a result of the large surface area for oxygen supply. However, 2 m of the tube length was adequate for a 1$\ell$ vessel. The larger blade type of impeller was effective to enhance the kLa values because of its high mixing intensity. In culture medium supplemented with 5% serum, kLa values were reduced to approximately 40% probably due to the viscosity. We also obtained the normal cell concentration of $5{\times}10^6$ cells/m$\ell$ of HepG2 on microcarriers, which could be achieved in a typical bioreactor for animal cell culture.

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Performance Prediction of Centrifugal Compressors (원심 압축기의 성능 예측)

  • 오형우;정명균
    • Transactions of the Korean Society of Automotive Engineers
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    • v.5 no.2
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    • pp.136-148
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    • 1997
  • The present study has been carried out to develop a computational procedure for the analysis of the off-design performance in centrifugal compressors with vaneless diffusers by integrating empirical loss models and analytical equations. Losses in centrifugal compressors stem from a number of sources and their exact calculation is not yet possible. This study investigates several modeling schemes and shows that a fairly good prediction can be achieved by a proper selection of the most important flow parameters resulting form a meanline one-dimensional analysis. The performance maps for compressors are calculated and compared with measured performance maps. The off-design performance characteristics in terms of the pressure ratio vs. mass flow produced have generally correct forms. However, no universal means have been found to predict accurately the onset of surge. The prediction method developed through this study can serve as a tool to ensure good matching between parts and it can assist the understanding of the operational characteristics of general purpose centrifugal compressors.

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Manufacture of ZPP Granule Using the LabRAM Mixer (LabRAM Mixer를 이용한 ZPP 입자 제조)

  • Jeong, Hyeheun;Kim, Junhyung;Ko, Seungwon;Ryu, Byungtae
    • Journal of the Korean Society of Propulsion Engineers
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    • v.21 no.4
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    • pp.63-70
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    • 2017
  • ZPP (Zirconium-Potassium Perchlorate) is type of primary charge initiators for PMD (Pyrotechnic Mechanical Device) system. The binder component dissolved in the solvent is precipitated to suspended particles in the granules. The LabRAM Mixer uses resonance phenomenon to transfer energy, unlike blade equipment that utilizes mechanical contact. In this study, the properties of the particles prepared by the LabRAM Mixer were evaluated with the changes of the conditions.